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ISSN 2469-0228
Recibido: 21 de agosto 2023 - Aceptado: 24 de febrero 2024 - Publicado: 27 de marzo 2024
Para citar este artículo: Leonardo Sebastián Filippi, Flavio Bellardini, José Luis Carballido, Agustín Pérez-Moreno,
& Alberto Carlos Garrido (2024). Sauropod diversity (Dinosauria: Sauropoda) of Cerro Overo – La Invernada (Bajo de
la Carpa Formation, Santonian), northeastern Neuquén Basin, and paleoecological implications for Upper Cretaceous
sauropod faunas. Publicación Electrónica de la Asociación Paleontológica Argentina 24(1): 71–96.
Link a este artículo: http://dx.doi.org/10.5710/PEAPA/24.02.2024.484
1. Museo Municipal Argentino Urquiza. Chos Malal 1277, Q8319BFA Rincón de los Sauces, Neuquén, Argentina.
2. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Godoy Cruz 2290, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina.
3. Instituto de Investigación en Paleobiología y Geología (IIPG), Universidad Nacional del Rio Negro. Av. Roca 1242, R8332EXZ General Roca, Río Negro,
Argentina.
4. Museo Paleontológico Egidio Feruglio. Av. Fontana 140, U9100GYO Trelew, Chubut, Argentina.
5. División Paleontología de Vertebrados, Facultad de Ciencias Naturales y Museo (Anexo Laboratorios). Avenida 122 y 60, B1900WA La Plata, Buenos
Aires, Argentina.
6. Museo Provincial de Ciencias Naturales ‘Prof. Dr. Juan A. Olsacher’, Dirección Provincial de Minería. Etcheluz y Ejército Argentino, Q8340AUB Zapala,
Neuquén, Argentina.
7. Centro de Investigación en Geociencias de la Patagonia (CIGPat), Departamento de Geología y Petróleo, Facultad de Ingeniería, Universidad Nacional
del Comahue. Buenos Aires 1400, Q8300IBX Neuquén, Neuquén, Argentina.
Asociación Paleontológica Argentina
Maipú 645 1º piso, C1006ACG, Buenos Aires
República Argentina
Tel/Fax (54-11) 4326-7563
Web: www.apaleontologica.org.ar
www.peapaleontologica.org.ar
Sauropod diversity (Dinosauria: Sauropoda) of
Cerro Overo – La Invernada (Bajo de la Carpa
Formation, Santonian), northeastern Neuquén
Basin, and paleoecological implications for Upper
Cretaceous sauropod faunas
LEONARDO SEBASTIÁN FILIPPI1,2
FLAVIO BELLARDINI2,3
JOSÉ LUIS CARBALLIDO2,4
AGUSTÍN PÉREZ-MORENO2,5
ALBERTO CARLOS GARRIDO6,7
©2024 Filippi, Bellardini, Carballido, Pérez-Moreno, & Garrido
71
SAUROPOD DIVERSITY (DINOSAURIA: SAUROPODA) OF CERRO
OVERO – LA INVERNADA (BAJO DE LA CARPA FORMATION,
SANTONIAN), NORTHEASTERN NEUQUÉN BASIN, AND
PALEOECOLOGICAL IMPLICATIONS FOR UPPER CRETACEOUS
SAUROPOD FAUNAS
LEONARDO SEBASTIÁN FILIPPI1,2, FLAVIO BELLARDINI2 ,3 , JOSÉ LUIS CARBALLIDO2 ,4 , AGUSTÍN PÉREZ-MORENO2 ,5 , A ND
ALBERTO CARLOS GARRIDO6, 7
1Museo Municipal Argentino Urquiza. Chos Malal 1277, Q8319 BFA Rincón de los Sauces, Neuquén, Argentina. lsfilippi@gmail.com
2Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Godoy Cruz 2290, C1033AAJ Ciudad Autónoma de Buenos Aires, Argentina.
3Instituto de Investigac ión en Paleobiología y Geología (IIPG), Unive rsidad Nacional del Rio Negro. Av. Roca 1242, R8332EXZ General Roca, Río Negro, Argentina.
flaviobellardini@gmail.com
4Museo Paleontológico Egidio Feruglio. Av. Fontana 140, U9100GYO Trel ew, Chubut, Argentina. jcarballido@mef.org.ar
5División Paleontología de Vertebrados, Facultad de Ciencias Naturales y Museo (Anexo Laboratorios). Avenida 122 y 60, B1900WA La Plata, Buenos Aires, Argentina.
aperezmoreno7@gmail.com
6Museo Provincial de Ciencias Naturales ‘Prof. Dr. Juan A. Olsacher’, Dirección Provincial de Minería. Etcheluz y Ejército Argentino, Q8340AUB Zapala, Neuquén,
Argentina. albertocarlosgarrido@gmail.com
7Centro de Investigación en Geociencias de la Patagonia (CI GPat), Departamento de Geología y Petróleo, Facultad de In geniería, Universidad N acional del Comahue.
Buenos Aires 1400, Q830 0IBX Neuquén, Neuquén, Argentina.
LSF: https://o rcid.org/0000-0003-0743-8294; FB: https://orcid.org/0000-0 003-1616-8548; JLC: https://orcid.org/0000-0003-3227-8034;
APM: https://o rcid.org/0000-0003-0674-2585; ACG: https://orci d.org/0000-0002-9882-9567
Abstract. The Upper Cretaceous fossil vertebrate fauna of the Bajo de la Carpa Formation (Santonian), derived from several different locations
in the Neuquén Basin, is relatively abundant and diverse, comprising mainly small to medium-sized reptiles, birds and fishes. The Cerro Overo
– La Invernada locality (CO – LI), in the north of the basin, records a similar faunal component for that age, but stands out for its relatively
greater abundance and diversity of titanosaur sauropods. The study of the materials presented here allows us to establish the presence of
specimens of sauropods other than Overosaurus, the only titanosaur recorded so far in the area, the coexistence of small–medium sized forms
with larger forms, which in turn represent some forms with more basal characteristics and others with more derived features. The abundance
of the record of sauropods in CO – LI shows both morphological and evolutionary variations, so the discovery of more complete specimens will
allow paleofaunistic, paleobiological, and paleoecological studies to be carried out. This will provide a better understanding of the role of
titanosaurian sauropods in Late Cretaceous ecosystems.
Key words. Sauropoda. Titanosauria. Diversity. Upper Cretaceous. Neuquén Basin.
Resumen. DIVERSIDAD DE SAURÓPODOS (DINOSAURIA: SAUROPODA) DE CERRO OVERO – LA INVERNADA (FORMACIÓN BAJO DE LA CARPA,
SANTONIANO), NOROESTE DE LA CUENCA NEUQUINA E IMPLICACIONES PALEOBIOLÓGICAS DE LA FAUNA DE SAURÓPODOS DEL CRETÁCICO
SUPERIOR. La fauna de vertebrados fósiles del Cretácico Superior proveniente de la Formación Bajo de la Carpa (Santoniano) de diferentes
localidades de la Cuenca Neuquina, es relativamente abundante y diversa; está compuesta principalmente por formas de reptiles, aves y peces
de pequeño y mediano tamaño. La localidad de Cerro Overo – La Invernada (CO – LI), en el norte de la cuenca, registra para dicha edad, un
componente faunístico similar, pero destacándose por una abundancia y diversidad relativamente mayor de saurópodos titanosaurios. El
estudio de los materiales presentados aquí permite establecer la presencia de especímenes de saurópodos diferentes a Overosaurus, el único
titanosaurio registrado hasta el momento en el área, y la coexistencia de formas de pequeño-mediano tamaño con formas más grandes, que
representan a su vez algunas formas con características más basales y otras con rasgos más derivados. La abundancia del registro de
saurópodos en CO – LI muestra variaciones tanto morfológicas como evolutivas, por lo que el hallazgo de ejemplares más completos permitirá
llevar adelante estudios paleofaunísticos, paleobiológicos y paleoecológicos. Esto brindará una mejor comprensión del papel de los saurópodos
titanosaurios en los ecosistemas del Cretácico Superior.
Palabras clave. Sauropoda. Titanosauria. Diversidad. Cretácico Superior. Cuenca Neuquina.
©2024 Filippi, Bellardini, Carballido, Pérez-Moreno, & Garrido | CC BY-NC 4.0 | Acceso Abierto - Open Access
Año 2024 - 24(1): 71–96
ARTÍCULO
Publicación Electrónica - 2024 - Volumen 24(1): 71–96
72
CERRO OVERO – LA INVERNADA is a large area near Rincón de los
Sauces city (Neuquén Province, Argentina) (Fig. 1), where
the continental sediments of the Bajo de la Carpa Formation
with a Santonian age (Upper Cretaceous) are exposed. The
outcrops of this formation are exposed in different areas of
northern Argentinean Patagonia and have shown to have
one of the greatest diversity of Cretaceous vertebrates
registered in Argentina (Bonaparte, 1991; Calvo & González
Riga, 2003; Apesteguía, 2004; Turner & Calvo, 2005; Fiorelli
& Calvo, 2007; Ezcurra & Méndez, 2009; Gianechini et al.,
2011; Juárez Valieri & Calvo, 2011; Martinelli et al., 2012;
Filippi et al., 2015; Porfiri et al., 2018; Lío et al., 2018; Coria
et al., 2019). The faunal component of the different localities
of the Neuquén Basin where the Bajo de la Carpa Formation
crops out and fossil vertebrates have been recorded,
corresponds to small-bodied forms such as the theropod
dinosaurs Alvarezsaurus calvoi (Bonaparte, 1991) and
Velocisaurus unicus (Bonaparte, 1991), Achillesaurus
manazzonei (Martinelli & Vera, 2007), enantiornithine birds
such as Neuquenornis volans (Bonaparte, 1991) and
Patagopterix deferrariisi (Alvarenga & Bonaparte, 1992),
crocodyliforms such as Notosuchus terrestris (Smith-
Woodward, 1896), Cynodontosuchus rothi (Smith-Woodward,
1896), Comahuesuchus brachybuccalis (Bonaparte, 1991),
Peirosaurus tormini (Gasparini et al., 1991), Neuquensuchus
universitas (Fiorelli & Calvo, 2007), Wargosuchus australis
(Martinelli & Pais, 2008), and Barrosasuchus neuquenianus
(Coria et al., 2019), snakes such as Dinilysia patagonica (Smith-
Woodward, 1901), chelid turtles such as Lomalatachelys
neuquina (Lapparent de Broin & de la Fuente, 2001) and
dipnoan fish such as Ceratodus kaopen (Apesteguía et al.,
2007), and to a lesser extent by medium-sized forms such
as the sauropod dinosaurs Bonitasaura salgadoi (Apesteguía,
2004) and Rinconsaurus caudamirus (Calvo & González Riga,
2003), theropod such as Tratayenia rosalesi (Porfiri et al.,
2018), and crocodyliforms such as Pehuenchesuchus enderi
Figure 1. Map showing the location of Cerro Overo – La Invernada (CO – LI) fossil area. Scale bar= 100 km.
FILIPPI ET AL.: TITANOSAUR DIVERSITY FROM CERRO OVERO–LA INVERNADA (SANTONIAN)
73
(Turner & Calvo, 2005). The CO – LI locality yielded a great
diversity of vertebrates including medium-sized theropods
(Viavenator exxoni Filippi et al., 2016; Llukalkan aliocranianus
Gianechini et al., 2021), ornithopod (Mahuidacursor lipanglef
Cruzado-Caballero et al., 2019), and sauropod (Overosaurus
paradasorum Coria et al., 2013), crocodiles (Kinesuchus overoi
Filippi et al., 2018), small-sized forms such as dipnoan fishes
(Rinconodus salvadori Panzeri et al., 2022) and chelidae
turtles (under study). Presently, all known sauropod
dinosaurs from the Bajo de la Carpa Formation are members
of Colossosauria, a clade recently redefined by Carballido et
al. (2022) as a stem lineage formed by titanosaurs closely
related to Patagotitan mayorum (Carballido et al., 2017) than
to Saltasaurus loricatus (Bonaparte & Powell, 1980), most
probably representing two lineages of this clade. Bonitasaura
(Apesteguía, 2004) and Traukutitan (Juárez-Valieri & Calvo,
2011) are considered members of Lognkosauria (although
the latter has never been included in a phylogenetic
analysis), whereas Overosaurus (Coria et al., 2013) is
considered as an aeolosaurian, a derived lineage of
Rinconsauria (Coria et al., 2013; Filippi et al., 2019; Silva
Junior et al., 2019; Hechenleitner et al., 2020; Gallina et al.,
2021). Despite the diverse vertebrate record from the CO – LI
locality, and despite the fact that in most continental
Cretaceous outcrops from Patagonia are dominated by
sauropods, to this point only the aeolosaurine Overosaurus
has been reported from this unit. Explorations and fieldwork
carried out over the space of more than a decade, enabled
the recovery of numerous titanosaur sauropod remains
from this locality.
The materials described here, although isolated, show
the great diversity of titanosaur forms that probably co-
existed in the area during the Santonian Stage. Thus, the
described materials contribute to improving the knowledge
of the evolution of the Cretaceous ecosystems, at least in
this area of Patagonia.
GEOLOGICAL SETTING
The materials described come from the CO – LI area, lo-
cated 50 km southwest of Rincón de los Sauces (Fig. 1),
Neuquén Province, Patagonia, Argentina. The outcrops are
assigned to the Bajo de la Carpa Formation, Río Neuquén
Subgroup, Upper Cretaceous (Santonian). At its base, this
formation conformably overlies the Plottier Formation of
the older Río Neuquén Subgroup, and it is in turn overlain
by the Anacleto Formation, the youngest and uppermost
formation of the Neuquén Group. The aforementioned for-
mation is composed by thick beds of medium to fine grained
size sandstones and interbedded red massive mudstones,
interpreted as anastomosed fluvial system deposits
(Méndez et al., 2015; Cruzado-Caballero et al., 2018).
MATERIALS AND METHODS
Materials studied. The materials used in this research are
as follows: Three isolated teeth (MAU-Pv-LI-645, MAU-Pv-
LI-646 and MAU-Pv-CO-650), a partial ?anterior cervical
vertebra (MAU-Pv-LI-602), a partial middle-to-posterior
dorsal vertebra (MAU-Pv-CO-671), a complete first caudal
vertebra (MAU-Pv-LI-670), a partial anterior caudal verte-
bra (MAU-Pv-CO-407), a partial anterior caudal vertebra
with proximal hemal fragments (MAU-Pv-LI-601), a partial
distal-most anterior caudal centrum (MAU-Pv-LI-669), a
sequence of six articulated middle caudal vertebrae and
three hemal arches (MAU-Pv-LI-600) and a partial posterior
caudal centrum (MAU-Pv-CO-668).
Anatomical terminology. Anatomical terminology used here
follows traditional or ‘Romerian’ directional terms (e.g.,
posterior, anterior) for skeletal structures (Wilson, 2006).
The nomenclature for vertebral laminae follows Wilson
(1999) and the nomenclature for vertebral fossae follows
Wilson et al. (2011).
Numerical indices. Three numerical indices have been used;
the aEI, the CI, and the SI. The average elongation index
(aEI; sensu Chure et al., 2010), calculated as the centrum an-
teroposterior length (excluding articular ball) divided by the
mean average value of the posterior articular surface medi-
olateral width and dorsoventral height, is considered here
instead the elongation index, since this can be influenced by
the compaction of the remains. Compression Index (CI,
sensu Díez Díaz et al., 2013b), is calculated as the maximum
labiolingual width divided by the maximum mesiodistal
width of the crown. Slenderness Index (SI, sensu Díez Díaz
et al., 2013b), calculated as the length of the tooth crown
divided by its maximum mesiodistal width, as defined by
Upchurch (1998).
Institutional abbreviations. MAU-Pv-CO, Colección Paleon-
tología de Vertebrados Cerro Overo, Museo Municipal Ar-
gentino Urquiza, Rincón de los Sauces, Neuquén, Argentina;
MAU-Pv-CRS, Colección Paleontología de Vertebrados
Cañadón Río Seco, Museo Municipal Argentino Urquiza,
Rincón de los Sauces, Neuquén, Argentina; MAU-Pv-LI,
Colección Paleontología de Vertebrados Loma del Lindero,
Museo Municipal Argentino Urquiza, Rincón de los Sauces,
Neuquén, Argentina; MLP, Museo de La Plata, La Plata,
Buenos Aires, Argentina; MPCA, Museo Provincial Carlos
Ameghino, Cipolletti, Río Negro, Argentina.
Anatomical abbreviations. ACDL, anterior centrodiapophy-
seal lamina; ACPL, anterior centroparapophyseal lamina;
CPAF, centroparapophyseal fossa; CPOF, centropostzy-
gapophyseal fossa; CPOL, centropostzygapophyseal lam-
ina; cr, cervical rib; CPRF, centroprezygapophyseal fossa;
LCPOL, lateral centropostzygapophyseal lamina; PACDF,
parapophyseal centrodiapophyseal fossa; PCDL, posterior
centrodiapophyseal lamina; PCPL, posterior centropara-
pophyseal lamina; POCDF, postzygocentrodiapophyseal
fossa; PODL, postzygodiapophyseal lamina; POSL, post-
spinal lamina; PRDL, prezygodiapophyseal lamina; PRSL,
prespinal lamina; SDF, spinodiapophyseal fossa; SPDL,
spinodiapophyseal lamina; SPOF, spinopostzygapophyseal
fossa; SPOL, spinopostzygapophyseal lamina; SPRF,
spinoprezygapophyseal fossa; SPRL, spinoprezygapophy-
seal lamina; STPOL, single intrapostzygapophyseal lamina;
TPOL, intrapostzygapophyseal lamina; TPRL, intraprezy-
gapophyseal lamina.
SYSTEMATIC PALEONTOLOGY
DINOSAURIA Owen, 1842
SAURISCHIA Seeley, 1888
SAUROPODA Marsh, 1878
TITANOSAURIFORMES Salgado et al., 1997
SOMPHOSPONDYLI Wilson & Sereno, 1998
Somphospondyli indet.
Figure 2.1–2.4
Material. Isolated tooth MAU-Pv-LI-645 (Fig. 2.1–4).
Description. The material is represented by the tooth
MAU-Pv-LI-645 (Morphotype 1) which is robust, with a
lingually beveled crown in its distal third, showing a sub-
cylindrical shape in cross-section. In the crown, the lingual
surface is slightly flat, whereas the labial surface is convex.
This tooth is similar in shape to the teeth of some basal
somphospondylians (e.g., Ligabuesaurus leanzai Bonaparte
et al., 2006) and basal titanosaurs, especially members
of Colossosauria (e.g., Patagotitan Carballido et al., 2017,
Bonitasaura Apesteguía, 2004), and differing from the fully
circular teeth of the Morphotype 2 (MAU-Pv-LI-646 and
MAU-Pv-CO-650) and most members of Saltasauroidea
(e.g., Tapuiasaurus macedoi, Nemegtosaurus mongoliensis,
Rapetosaurus krausei,Lirainosaurus astibiae; Nowinski, 1971;
Sanz et al., 1999; Curry Rogers & Forster, 2001; Zaher et al.,
2011). The tooth has longitudinal mesiodistal carinae that
delimit the labial face from the lingual one that extend to
the apex of the tooth, as in Antarctosaurus sp. (Huene, 1929),
Rinconsaurus (Calvo & González Riga, 2003), Bonitasaura,
and Alamosaurus sanjuanensis (Gilmore, 1922). Pitekunsaurus
macayai (Filippi & Garrido, 2008) has longitudinal carinae
similar to MAU-Pv-LI-645, but they are less marked. In
mesiodistal view, the carinae are centered on the tooth in
MAU-Pv-LI-645, as in Bonitasaura, differing from the lin-
gually displaced carinae observed in Rinconsaurus and
Pitekunsaurus (Filippi & Garrido, 2008). The enamel is well
preserved, showing several longitudinal ridges that form
rough ornamentation on both labial and lingual surfaces. A
single lingual wear facet is present in the tooth MAU-Pv-LI-
645, which is clearly recognized given the curvature of its
crown.
TITANOSAURIA Bonaparte & Coria, 1993
EUTITANOSAURIA Sanz et al., 1999
Eutitanosauria indet.
Figure 2.5–2.12
Material. Isolated teeth MAU-Pv-LI-646 and MAU-Pv-CO-
650 (Fig. 2.5–12).
Description.The material is represented by the teeth MAU-
Pv-LI-646 and MAU-Pv-CO-650 (Morphotype 2), which are
slightly smaller than MAU-Pv-LI-645, with straight, slender
crowns, circular in cross-section, and without carinae on
their mesial and distal edges. Although the enamel is not
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FILIPPI ET AL.: TITANOSAUR DIVERSITY FROM CERRO OVERO–LA INVERNADA (SANTONIAN)
75
well preserved, it has smooth surfaces without ornamenta-
tion. The absence of wrinkled patterns could reflect a high
degree of wear in these teeth. The SI of morphotype 2 teeth
is slightly higher than 4, but was probably higher given the
degree of wear, while the CI is 1. Following García & Cerda
(2010) single and planar wear facets are present in both
teeth. MAU-Pv-CO-650 presents two wear facets, the
smaller one is here tentatively considered as being on the
lingual surface, whereas the larger one is labially located. By
contrast MAU-Pv-LI-646 has a single wear facet located on
the lingual side.
Comments. According to the general morphology, two mor-
photypes are recognized amongst the preserved teeth
(Morphotype 1, represented by MAU-Pv-LI-645, and Mor-
photype 2, represented by MAU-Pv-LI-646 and MAU-Pv-
CO-650), being the three teeth interpreted as functional
teeth due to the presence of apical wear facets on them.
We consider MAU-Pv-LI-645, MAU-Pv-LI-646, and MAU-
Pv-CO-650 as narrow crowned (Barrett & Upchurch, 2005)
and pencil chisel-like teeth (sensu Calvo, 1994), a common
shape among diplodocoids (e.g., Diplodocus Marsh, 1878;
Dicraeosaurus sp. Janensch, 1914, Nigersaurus taqueti Sereno
et al., 1999, Lavocatisaurus agrioensis Canudo et al., 2018) and
derived titanosaur sauropods (e.g., Bonitasaura,Rinconsaurus,
Pitekunsaurus,Nemegtosaurus,Rapetosaurus,Antarctosaurus
sp.). Amongst titanosaurs, basal forms such as Sarmientosaurus
musacchioi (Martínez et al., 2016) and Diamantinasaurus
matildae (Hocknull et al., 2009; Poropat et al., 2022, 2023),
present broad-crowned and compressed cone-chisel-like
teeth (sensu Calvo, 1994), with sub-cylindrical teeth with
relatively low SI (around 3). Our morphotype 1 has a sub-
cylindrical shape with a SI higher than 4 and a CI of 0.44,
which are more derived characters among titanosaurs. Simi-
lar shaped and slender teeth are common amongst relatively
basal titanosaurs and members of Colossosauria (e.g.,
Patagotitan [SI= 3.4; CI= 0.8], Quetecsaurus rusconii González
Figure 2. Sauropod teeth MAU-Pv-LI-645, MAU-Pv-LI-646 and MAU-Pv-CO-650 in 1, 5, 9, lingual; 2, 6, 10, labial; 3, 7, 11, lateral; and 4, 8,
12, transversal views. Scale bar= 1 cm. Anatomical abbreviations: ca, carena; lawf, labial wear facet; liwf, lingual wear facet.
Riga & Ortiz, 2014 [SI= 4.3; CI= 0.9]). Additionally, MAU-Pv-
LI-645 shares the presence of mesiodistal carinae with
some titanosaurs such as Antarctosaurus sp. and Rincon-
saurus but differs from the more derived saltasauroid ti-
tanosaurs (Apesteguía, 2004). On the contrary, morphotype
2, with its cylindrical crowns and absence of carena, shares
these characters with derived members of Saltasauroidea
and differs from more basal titanosaurs (e.g., Rapetosaurus
[SI= 7.8, CI= 1], Lirainosaurus [SI= 3.78, CI= 0.91]). Therefore,
although both teeth are assigned to Titanosauria indet,
morphotype 2 presents some characteristics that allow a
more precise assignment to more derived members of
Saltasauroidea.
TITANOSAURIFORMES Salgado et al., 1997
SOMPHOSPONDYLI Wilson & Sereno, 1998
Somphospondyli indet.
Figure 3
Material. Partial ?anterior cervical vertebra MAU-Pv-LI- 602
(Fig. 3).
Description. This cervical vertebra is almost complete, lacking
part of the anterior articular surface, right postzygapophysis,
and both prezygapophysis. The vertebra is slightly longer
than tall, interpreting it as an anterior cervical vertebra on
the basis of the ventral position of the parapophysis, the
height of the neural spine, the aEI larger than 4, and the
marked CPOF. Such elongated centrum is widespread
amongst titanosaurs, with few exceptions having propor-
tionally shorter centra (e.g., Neuquensaurus australis,
Isisaurus colberti; Lydekker, 1893; Jain & Bandyopadhyay,
1997). The vertebral centrum is rectangular in lateral and
ventral views, with opisthocoelous articulation. In anterior
and posterior views, the articular surfaces are subcircular,
being almost as tall as they are wide, slightly dorsoventrally
compressed (see Tab. S2, Supplementary Information).
Amongst titanosaurs, circular articular surfaces are wide-
spread amongst Colosossauria, but probably more common
within the Aeolosaurini (e.g., Overosaurus). The lateral sur-
faces are nearly flat, with shallow depressions on the ante-
rior half, without true pneumatic foramina, such us in other
titanosaurs. The ventral surface is transversely concave
between the parapophyses and slightly convex posteriorly.
In lateral view, the posterior articular surface of the centrum
is inclined dorsoanteriorly, with the dorsal edge more ad-
vanced than the ventral edge as in Brasilotitan nemophagus
(Machado et al., 2013). Posteriorly to the diapophysis, there
is a longitudinal PCDL, which extends almost until the dorso-
lateral margin of the posterior articular surface. The para-
pophyses are projected lateroventrally at an angle of about
20° with respect to the horizontal plane, causing the cervi-
cal ribs to lie below the level of the ventral border of the ver-
tebral centrum, a character found in several titanosaurs
(e.g., Rapetosaurus, Overosaurus, Kaijutitan maui; Filippi et al.,
2019) and differing with other with an even more ventrally
projected parapophysis (e.g., Patagotitan). Although the
prezygapophysis has not been preserved, the PRDL is
present and has a conspicuous longitudinal edge similar to
that observed in Overosaurus, with a small epipophysis-like
prominence distally (Fig. 3.2). Of the zygapophyses, only the
left postzygapophysis has been preserved, showing a
subcircular articular surface inclined 30° with respect to the
ventral surface of the centrum. The postzygapophyses do
not extend beyond the posterior articular surface, as in
Saltasaurus. Dorsally to the postzygapophyses, a latero-
posterior prominence is observed that would correspond to
the presence of an epipophysis as in the anterior cervical
vertebra of Kaijutitan. Moreover, a robust SPOL is present.
Laterally, the neural arch presents a small POCDF delimited
ventrally by the PCDL and anterodorsally by the PODL.
The PODL is a single lamina, different from the two PODL
segments (diapophyseal and zygapophyseal) present in
Bonitasaura and Uberabatitan ribeiroi (Salgado & de Souza
Carvalho, 2008). Dorsally to this fossa, a well-developed
SDF is present, delimited posteroventrally by the PODL and
anterodorsally by the SPRL. The SPRL is wide and joins the
prezygapophysis with the anterolateral border of the neural
spine. In anterior view, delimited ventrally by the TPRL and
laterally by the SPRL, a SPRF with a subelliptic contour is
observed. Posterior to the location of the prezygapophyses,
the SPRL presents marked dorsoventrally extended de-
pressions. The neural spine is dorsally incomplete, relatively
low in lateral view, and bulbous in anterior view, differing
from the triangular and laterally compressed spine in
Malawisaurus dixeyi (Gomani, 2005), Futalognkosaurus dukei
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Figure 3. Incomplete anterior cervical vertebra MAU-Pv-LI- 602. 1, anterior; 2, posterior; 3, lateral; 4, dorsal; and 5, ventral views. Scale bar=
5 cm. Additional anatomical abbreviations: cr, cervical rib; dp, diapophysis; ep, epipophysis; ICPOL, lateral centropostzigapophyseal lamina;
mdCPOL, median division of the centropostzigapophyseal lamina; nc, neural canal; ns, neural spine; pnf, pneumatic foramen; poz,
postzygapophysis; pp, parapophysis.
(Calvo et al., 2007b, 2007c), and Uberabatitan. Overosaurus
presents in posterior cervicals a similar bulbous neural
spine, although more anterior cervical vertebrae of this
taxon were not preserved. In the posterior view, positioned
posterior to the neural spine and delimited laterally by
SPOL, a deep SPOF is observed. Laterally to the SPOF, on
both sides, there are two asymmetric, dorsoventrally
elongated fossae with a subelliptic contour. In posterior
view, over the neural canal, a small CPOF can be observed,
delimited laterally by the LCPOL, medially by the medial di-
vision of the CPOL, and dorsally by the TPOL. The posterior
cervical vertebrae of Overosaurus (Coria et al., 2013, fig.
2D), Rinconsaurus (Pérez Moreno et al., 2022, fig. 3.4) and
Bonitasaura (Gallina & Apesteguía, 2015, fig. 4B) have a
similar CPOF, but with a different configuration of the
laminae that delimit it, probably due to the posterior posi-
tion of these vertebrae.
Comments. The record of the anterior cervical vertebrae of
titanosaurs is scarce, therefore, the possibilities of making
good comparisons are limited. Unfortunately, the only ti-
tanosaur sauropod known from the study area, Overosaurus,
has not preserved middle cervical vertebrae. However,
some general features present in MAU-Pv-LI-602 (e.g.,
cervical ribs located below the level of the ventral border of
the centrum, presence of a longitudinal border over the
PRDL, bulbous neural spine) are shared with the posterior
cervical vertebrae of Overosaurus. However, the articular
surfaces of cervical vertebrae are wider than high in
Overosaurus, differing from that subcircular one of MAU-Pv-
LI-602. Nevertheless, similarly subcircular articular surfaces
are widespread amongst titanosaurs related to Aeolosaurini
(e.g., Rinconsaurus,Muyelensaurus,Patagotitan). On the other
hand, the presence of two pneumatic fossae on both lateral
sides of the SPOF, is a character not observed in the anterior
cervical vertebrae of other titanosaurs. Therefore, the cervical
element, although seems to be related to Colossosauria
and probably Aeolosaurini, presents a number of differences
with Overosaurus that can be interpreted as, at least,
species-level differences.
TITANOSAURIA Bonaparte & Coria, 1993.
EUTITANOSAURIA Sanz et al., 1999
Eutitanosauria indet.
Figure 4
Material. Partial middle-to-posterior dorsal vertebra MAU-
Pv-CO-671 (Fig. 4).
Description. This element, probably the fourth or fifth
dorsal vertebra, is incomplete, lacking part of the dorsal
portion of the anterior articular surface, dorsodistal part of
transverse processes, the zygapophyses, except part of the
right prezygapophysis, and the distal portion of the neural
spine. The vertebral centrum is strongly opisthocoelous as
in most Sauropoda, slightly wider than tall in posterior view.
The lateral surfaces of the centrum are anteroposteriorly
concave and have deep and eye-shaped pleurocoels close
to the dorsal margin of the centrum, as in several ti-
tanosaurs. The ventral surface is slightly anteroposteriorly
concave and transversely convex. In anterior view, the para-
pophysis is dorsolaterally directed and located above the
dorsal edge of the neural canal, almost at the level of the
prezygapophysis. Although the articular facets of the para-
pophyses are eroded, a subelliptic morphology is inferred by
the long axis dorsoventrally extended and posterodorsally
directed. The parapophyses are connected ventrally to the
centrum by a robust ACPL and an inclined PCPL. This lamina,
together with the ACPL, delimited an elliptical CPAF. Pos-
terodorsally to that, opens a wider, deep, and triangular
PACDF, which is delimited posteriorly by the PCDL, dorsally
by the diapophysis, and ventrally by the PCPL (Fig. 4.3).
The articular surface of the part of the preserved prezy-
gapophysis is elliptic, with its major axis lateromedially
directed, and inclined approximately 30º with respect to the
horizontal in anterior view. The PRSL is weathered but
seems to have been more prominent towards the base of
the spine, as in Baurutitan britoi (Kellner et al., 2005),
Mendozasaurus neguyelap (González-Riga, 2003), and
Overosaurus, than apically, where it is narrow and thin, as in
other titanosaurs. The SPRL is absent, a condition that MAU-
Pv-CO-671 shares with Isisaurus, Overosaurus, Rinconsaurus,
and Saltasauridae (e.g., Saltasaurus, Opisthocoelicaudia
skarzynskii; Borsuk-Bialynicka, 1977). The postzygapophy-
ses show an elliptic morphology with the major axis located
dorsoventrally similar to the prezygapophyses, but with a
slightly greater angle of inclination. The postzygapophyses
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Figure 4. Incomplete middle-to-posterior dorsal vertebra MAU-Pv-CO-671 in 1, anterior; 2, posterior; and 3, lateral views. Scale bar= 10 cm.
Additional anatomical abbreviations: ACPL, anterior centroparapophyseal lamina; nc, neural canal; pl, pleurocoel; poz, postzygapophysis; prz,
prezigapophysis; STPRL, single intraprezygapophyseal lamina.
are connected to the centrum by robust and prominent
CPOL that projects from the middle of the ventral margin of
the articular surface, as in Pitekunsaurus, running distally to
the lateroposterior margin of the PCDL. This condition differs
from other titanosaurs (e.g., Neuquensaurus, Overosaurus,
Bonitasaura,Baurutitan) where the CPOL is projected from
the medioventral border of the articular surface of postzy-
gapophysis. Between the postzygapophysis, the TPOL is
prominent and V-shaped in posterior view, extending ven-
trally to form a TPOL as seen in Bonitasaura (Gallina &
Apesteguía, 2015, fig. 5H). In Pitekunsaurus, the V-shaped
TPOL is similar but less prominent (Filippi & Garrido, 2008,
fig. 6.5). The POSL is prominent proximally and weathered
apically, where it seems to be slightly wider. On both sides
of this POSL, the SPOF is subdivided by small accessory
laminae that unite the postzygapophyses with the POSL,
forming small subfossae of irregular contour not seen in other
titanosaur. The neural spine has not been preserved but is
tilted posteriorly about 40º from the horizontal in lateral view.
Comments. The new dorsal element MAU-Pv-CO-671 from
CO – LI shows a centrum with an opisthocoelous articula-
tion and wide, deep and eye-shaped lateral pneumatic
foramen, like in the 7th and 8th dorsal vertebrae of Overosaurus.
Moreover, they have an anteroposteriorly concave ventral
surface in lateral view, and however MAU-Pv-CO-671 lacks
the prominent ventral keel seen in Overosaurus. In MAU-Pv-
CO-671 the parapophysis is oval and connected to the
centrum via ACPL and PCPL, which frame a triangular CPAF,
as in Overosaurus. Moreover, both MAU-Pv-CO-671 and
Overosaurus lacks SPRL, as in some titanosaurians. On the
other hand, they differ in the position of CPOL, which in
Overosaurus it connects with the centrum from the lateroven-
tral margin of postzygapophysis, whereas in MAU-Pv-CO-
671 it starts more medioventrally. Finally, the new material
shows POSL, whereas it is absent in Overosaurus. The ab-
sence of the POSL in the dorsal vertebrae of Overosaurus is
considered as an autapomorphic feature by Coria et al.
(2013); however, Vila et al. (2022) suggest a more spread dis-
persion of this character within Sauropoda, being shared by
Muyelensaurus, Isisaurus, and Abditosaurus (Vila et al., 2022).
TITANOSAURIFORMES Salgado et al., 1997
SOMPHOSPONDYLI Wilson & Sereno, 1998
Somphospondyli indet.
Figure 5
Material. First caudal vertebra MAU-Pv-LI-670 (Fig. 5).
Description.An incomplete vertebra is here interpreted as
the first caudal vertebra, based on the asymmetric articular
surfaces of the centrum, being the condyle well-prominent
and the cotyle shallowly depressed, and the dorsoventrally
tall and anteroposteriorly compressed transverse process.
Despite that one more anterior position in the axial series
cannot be completely ruled out (as the last sacral), the ab-
sence of a marked ventral constriction of the centrum and
the lateroventral direction of the transverse process pre-
served (instead of transversally directed) is more concor-
dant with the caudal morphology than the sacral one. The
cotyle is smaller than the condyle, suggesting a morpho-
logical transition between the last sacral and the following
caudal vertebrae. A marked difference is also observed in
the first caudal element of Overosaurus. As in other ti-
tanosaurs, the centrum is procoelic, with a subcircular an-
terior articular surface and a posterior articular surface
wider than high. Amongst titanosaurs, the procoelous first
caudal centrum of this specimen differs from the biconvex
first caudal vertebra Saltasauroidea, such as Baurutitan,
Alamosaurus, and Neuquensaurus (MLP Ly 1 and 7; D’Emic &
Wilson, 2011). On the midline of the dorsal margin of the
condyle, there is an elliptic and deep notch. The centrum has
lateral and ventral surfaces slightly concave anteroposteriorly.
The ventral surface is transversely convex and lacks a ven-
tral keel and lateral ridges, it is relatively wider, differenti-
ating from the transversely compressed ventral surface of
sacral vertebrae (e.g., Overosaurus or Neuquensaurus) and
being more similar to the ventral surface of the anterior-
most caudal vertebra without articulation for the haemal
arches. In the left lateral portion of the centrum, below the
transverse process, there is a shallow depression where two
small foramina are observed (Fig. 5.3), as in Alamosaurus,
Neuquensaurus,Rinconsaurus, and Overosaurus; however, in
the latter, they are shallower, asymmetric, and located
on both lateral faces of the centrum. Although the trans-
verse processes are incomplete, they seem to be projected
lateroventrally, with a slight posterior inclination in lateral
view. The transverse process is proximally robust and
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Figure 5. First caudal vertebra MAU-Pv-LI-670 in 1, anterior; 2, posterior; 3, lateral; and 4, ventral views. Scale bar= 10 cm. Anatomical
abbreviations: nc, neural canal; pnf, pneumatic foramen; sr, sacral rib.
occupies, except for the condyle, the entire anteroposterior
length of the center. The transverse process would be
connected to the neural spine by a robust SPDL directed
anterolaterally in the dorsal view. The neural arch is located
on the anterior border of the vertebral centrum. None of the
zygapophyses and neural spine have been preserved.
Comments. MAU-Pv-LI-670, interpreted as the first caudal
vertebra, differs from Overosaurus for the transversely con-
vex ventral surface of the center, which is broad and slightly
transversely concave in Overosaurus. Moreover, the first
caudal vertebra of Overosaurus is quadrangular in posterior
view, whereas MAU-Pv-LI-670 is almost subtriangular.
SOMPHOSPONDYLI Wilson & Sereno, 1998
TITANOSAURIA Bonaparte & Coria, 1993
Titanosauria indet.
Figure 6
Material. Partial anterior caudal vertebra MAU-Pv-CO-407
(Fig. 6).
Description. This specimen is incomplete, preserving most
of the centrum and part of the neural arch, without the right
transverse process, both prezigapophyses, and the neural
spine (which solely preserves its ventral section). As in most
titanosaurs, the caudal vertebra has a strongly procoelic
center, with a centered and prominent condyle. The ante-
rior articular surface is subcircular with slight transversally
compression, whereas the posterior articular surface is
heart-shaped, with the dorsal surface of the centrum wider
than the ventral one. The lateral surfaces of the centrum are
deeply excavated and concave anteroposteriorly, whereas
the ventral surface is anteroposteriorly concave in lateral
view and transversely flat, with two low lateroventral crests
connecting articular surfaces for the hemal arches, which
are more prominent on the posterior margin of the ventral
surface. On the lateral and ventral surfaces, there are small
and oval vascular foramina, as in several diplodocoids and
titanosaurs (Bellardini et al., 2021). The neural arch is lo-
cated on the anterior border of the vertebral centrum, as in
most titanosauriformes, and has laterally projected and
dorsoventrally compressed transverse processes, as in
Aeolosaurini and Lognkosauria (Moreno et al., 2021). The
transverse process is lateroposteriorly directed in dorsal
view, proximally broad, and distally compressed; moreover,
it presents a sharp anteroventral border. The postzy-
gapophyses are dorsoventrally concave (Fig. 6.2), similar to
Adamantinasaurus mezzalirai (Santucci & Bertini, 2006b) and
Arrudatitan maximus (Santucci & Arruda-Campos, 2011;
Silva Junior et al., 2021), acquiring an ear-shaped mor-
phology in the posterior view. Between the postzy-
gapophyses, a small but deep SPOF is observed. Despite
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Figure 6. Incomplete anterior caudal vertebra MAU-Pv-CO-407 in 1, anterior; 2, posterior; 3, lateral; and 4, ventral views. Scale bar= 10 cm.
Additional anatomical abbreviations: nc, neural canal; poz, postzigapophysis; prz, prezigapophysis; tp, transverse process.
lacking the neural spine, there are short and prominent
SPOL. Dorsally to the SPOF, a proximal portion of the POSL
is present, with lateral edges distally divergent. Anteriorly
to the postzygapophyses, a small POCDF is observed, as in
Bonitasaura, Malawisaurus, Alamosaurus (Gilmore, 1946),
Bonatitan reigi (Martinelli & Forasiepi, 2004), Mendozasaurus,
Petrobrasaurus puestohernandezi (Filippi et al., 2011a) and
Narambuenatita palomoi (Filippi et al., 2011b). Although the
prezygapophyses have not been preserved, remnants of
these appearances indicate that they would project an-
terodorsally in lateral view.
Comments. Concave postzygapophyses articular facets on
anterior caudal vertebrae are considered by Santucci &
Bertini (2006) as an autapomorphy of Adamantinasaurus;
however, this condition is shared with MAU-Pv-CO-407,
where the concavity is more marked in posterior view.
MAU-Pv-CO-407 is an anterior caudal vertebra belonging
to a large-sized sauropod specimen (Tab. S2, Supplemen-
tary Information); however, the suture on the proximal
transverse process suggests an unossified structure, a
condition referred to as an immature ontogenetic stage
(Brochu, 1996). In this sense, MAU-Pv-CO-407 results in a
sauropod specimen larger than Overosaurus (Coria et al.,
2013), which could be considered an adult specimen due to
several osteological conditions of type materials (e.g., fused
sacral vertebrae, absence of neural sutures).
TITANOSAURIA Bonaparte & Coria, 1993
Titanosauria indet.
Figure 7
Material. Partial anterior caudal vertebra with proximal
hemal fragments MAU-Pv-LI-601 (Fig. 7).
Description. This vertebra preserves an almost complete
centrum and part of the neural arch, lacking the distal
portion of the right transverse process, the right prezy-
gapophysis and the distal part of the left one, both postzy-
gapophysis, and the neural spine. The vertebral centrum is
strongly procoelic, with the condyle positioned dorsally
in lateral view, as in Narambuenatitan, Mendozasaurus
(González Riga, 2005), Baurutitan, Adamantinasaurus, and
Aeolosaurus sp. (MPCA 27100). The cotyle is wider and taller
than the condyle, as in Rinconsaurus, differing from the
uniform anterior caudal centrum of Overosaurus. Indeed, in
MAU-Pv-LI-601 the anterior articular surface is subcircu-
lar, slightly dorsoventrally compressed, whereas the poste-
rior articular surface is wider than tall. The posterior half of
the centrum shows anteroposteriorly concave lateral sur-
faces. The ventral face is not clearly observable due to the
fusion of the hemapophyses of the haemal arch of the pre-
ceding vertebra (Fig. 7.1–3), although it would be narrower
than the dorsal surface. The transverse processes are short
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Figure 7. Incomplete anterior caudal vertebrae MAU-Pv-LI-601 in 1, anterior; 2, posterior; 3, lateral; and 4, dorsal views. Scale bar= 10 cm.
Additional anatomical abbreviations: ha, haemal arch; prz, prezigapophysis; tp, transverse process.
and tapering, dorsoventrally compressed, lateroposteriorly
projected in dorsal view, and laterodorsally curved in ante-
rior view, similar to Overosaurus. The neural arch is low and
is located in the anterior part of the vertebral centrum. A
preserved portion of the left prezygapophysis suggests
that it was projected anterodorsal. Between the preserved
portions of both prezygapophyses, a deep SPRF is ob-
served, as in different titanosaurians (e.g., Bonitasaura,
Pitekunsaurus, and Gondwanatitan faustoi; Kellner &
Azevedo, 1999).
Comments. The anterior caudal vertebra MAU-Pv-LI-601
presents a centrum that is wider dorsally than ventrally,
different from the transversely wide and ventrally flat an-
terior caudal centrum of Overosaurus. In Overosaurus, the
lateral surfaces of the centra are slightly anteroposteriorly
concave, whereas in Rinconsaurus and MAU-Pv-CO-407
they are deeper. In MAU-Pv-LI-601 an unusual condition is
observed, the anterior half of the lateral face of the centrum
is slightly convex, and the posterior half is concave. Fur-
thermore, MAU-Pv-LI-601 shows evidence of sutures in the
neural arch, around the transverse processes, which could
be indicating a subadult ontogenetic stage of the specimen.
On the other hand, the fusion of the proximal fragments of
the haemal arch could correspond to a probable pathologi-
cal specimen, which is under study.
TITANOSAURIFORMES Salgado et al., 1997
SOMPHOSPONDYLI Wilson & Sereno, 1998
Somphospondyli indet.
Figure 8
Material. Partial distal-most anterior caudal centrum MAU-
Pv-LI-669 (Fig. 8)
Description. This specimen is incomplete, preserving most
of the centrum and the basal portion of the left transverse
process. The centrum is as wide as tall, with amphicoelous
articulation; however, the anterior and posterior articular
surfaces are unusual, differing from traditional articulation
recorded within Sauropoda (e.g., procoelous, opisthocoelous,
amphiplatyan, etc.). Indeed, the anterior articular surface is
dorsally concave and ventrally almost straight, with a gentle
ventromedial prominence; in turn, the posterior articular
surface is ventrally slightly concave, whereas dorsally there
are two lateral bulbous prominences. Despite the unusual
condition of MAU-Pv-LI-669, we consider that the
alternative vertebral articulation proposed by Tidwell et al.
(2001) as procoelic-dystoplatyan better reflects the type of
its joint. Similar articular conditions are observed in other
titanosaurians, such as in the distal-most anterior caudal
vertebrae of Traukutitan, and the middle caudal vertebrae of
Rukwatitan bisepultus (Gorsak et al., 2014), Malawisaurus,
and Mendozasaurus. However, in Malawisaurus and
Mendozasaurus the anterior articular surface is slightly
concave and the posterior one shows a single dorsal
prominence, which is more reduced in Mendozasaurus than
Malawisaurus. On the other hand, in Traukutitan the distal-
most anterior caudal vertebrae, originally described as
middle caudal vertebrae (Juárez Valieri & Calvo, 2011), still
preserve part of the transverse process and are here
interpreted as distal-most anterior caudal vertebrae, which
shows a procoelic-dystoplatyan articulation. In MAU-Pv-LI-
669, the anterior articular surface in the center presents a
subcircular contour, while the posterior surface presents a
hexagonal contour in the posterior view. The lateral and
ventral surfaces of the centrum are anteroposteriorly
concave, whereas the ventral surface is transversely
straight and compressed, presenting prominent articular
surfaces for the hemaphophyses, especially posteriorly.
Moreover, there are several small vascular foramina on
the ventrolateral and ventral surfaces, as in several neo-
sauropods. In lateral view, the anterodorsal and posterodorsal
borders of the articular surfaces are anteriorly inclined, a
similar condition is seen in Traukutitan. The neural arch is
located in the anterior portion of the center. The postero-
dorsal surface of the vertebral centrum is slightly
anteroposteriorly concave, with a slight expansion close to
the dorsal margin of the posterior articular border as in
Traukutitan and Malawisaurus. The preserved transverse
process is laterally prominent, which allows us to infer that
it is a distal-most anterior caudal vertebra.
Comments. The distal-most anterior caudal MAU-Pv-LI-
669 differs from the procoelic anterior caudal vertebrae of
most titanosaurians; moreover, the anterodorsal and pos-
terodorsal margin of the center are straight in both taxa
and not anteriorly inclined as in MAU-Pv-LI-669. On the
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Figure 8. Incomplete distal-most anterior caudal centrum MAU-Pv-LI-669 in 1, anterior; 2, posterior; 3, lateral; and 4, ventral views. Scale
bar= 10 cm. Anatomical abbreviations: tp, transverse process.
other hand, Traukutitan shows an anteriorly inclined ante-
rior articular surface in lateral view, differing from the
straight anterior surface of MAU-Pv-LI-669, and a straight
posterior articular surface in anterior view, without the pos-
terodorsal bevelling seen in MAU-Pv-LI-669. Moreover, the
center of Traukutitan is anteriorly and ventrally wider than
MAU-Pv-LI-669, showing a general morphology more
similar to Overosaurus (e.g., ninth and tenth anterior cau-
dal vertebrae) than MAU-Pv-LI-669. However, the pos-
terodorsal margin of the distal-most anterior caudal
vertebrae of Traukutitan is dorsally prominent, as in MAU-
Pv-LI-669.
TITANOSAURIFORMES Salgado et al., 1997
SOMPHOSPONDYLI Wilson & Sereno, 1998
Somphospondyli indet.
Figure 9
Material. Sequence of six articulated middle caudal verte-
brae and three hemal arches MAU-Pv-LI-600 (Fig. 9).
Description. The articulated sequence is composed of five
almost complete middle caudal vertebrae and the anterior
articular surface and prezygapophyses remains of a sixth
one, two almost complete haemal arches, and a small
fragment of a third. The caudal vertebrae are procoelous,
quadrangular in appearance, higher than wide, with slightly
anteroposteriorly concave lateral and ventral surfaces. The
ventral aspect of the centrum is slightly narrower than the
dorsal aspect. On the lateral surface, at the base of the
neural arch, lateral prominences corresponding to vestiges
of the transverse processes are observed. The neural arch is
located in the anterior half of the vertebral centrum, with
the prezygapophysis surpassing the centrum, being a length
around half the length of the vertebral centrum. They are
mainly anterodorsally projected. In the first two elements
of MAU-Pv-LI-600, the posterior neural arch pedicels are
anteriorly inclined, as in Aeolosaurus rionegrinus (Powell,
1987) and Rapetosaurus, and particularly tall in lateral view,
being almost as tall as the centrum height. The articular
facets of the prezygapophyses project mediodorsally,
acquiring a pipe-like morphology in lateral view, especially in
the first three elements. The neural spine is transversely
compressed and widens posteriorly in dorsal view. The
vertebrae present an incipient SPRL, which delimits
between the prezygapophyses and the base of the neural
spine, a deep SPRF. The neural spine presents an acute,
practically straight anterior edge, which differs from the
SPRL (clearly observed in the 4th caudal of the sequence),
which could be interpreted as a PRSL. The dorsal edge of
the spine is convex and distally expanded in lateral view,
whereas the posterior edge is straight and more robust than
the anterior, which slopes posteriorly, conferring a posterior
inclination to the neural spine in lateral view. The postzy-
gapophyses are attached to the posterior part of the spine
by a short and robust SPOL. This short and robust SPOL was
named “bony processs” by Calvo et al. (2003) and is one of
the main synapomorphies of the Rinconsauria clade, as is a
character shared between Rinconsaurus and Muyelensaurus
(amongst other members of the clade). There is a SPOF
framed between the SPOL.
The caudal sequence MAU-Pv-LI-600 preserves also
three haemal arches, which are open Y-shaped type (Otero
et al., 2011) and articulated to the fourth and fifth caudal
vertebrae, the latter the best preserved and most complete
of the series. The distal process is half the length of the
dorsal rami, being laterally compressed and posteriorly
curved in lateral view.
Comments. The postzygapophyseal process, considered by
Calvo & González Riga (2003) as an autapomorphic feature
of Rinconsaurus, is a condition with a wider distribution
within Sauropoda (e.g., Overosaurus, Pitekunsaurus) and,
although it was recently retained as part of the unique
combination of characters in the emended diagnosis of
Rinconsaurus by Pérez-Moreno et al. (2022), it shows to have
a more widespread distribution amongst Rinconsauria. In
MAU-Pv-LI-600 the postzygapophyseal process is present,
but with less development than Rinconsaurus, as seen in
Overosaurus and Pitekunsaurus. Furthermore, in MAU-Pv-
LI-600 the ventral surface is transversely compressed,
narrower than in Overosaurus, and the prezygapophyses are
pipe-like and not rounded in lateral view as in Overosaurus.
MAU-Pv-LI-600 differs from Overosaurus also in presenting
tall, straight, and anteriorly inclined posterior neural pedicles,
which are slightly lower and convex in lateral view.
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TITANOSAURIA Bonaparte & Coria, 1993
Titanosauria indet.
Figure 10
Material. Partial posterior caudal centrum MAU-Pv-CO-668
(Fig. 10).
Description. This element is composed of the posterior
portion of the centrum and the base of the neural arch. The
FILIPPI ET AL.: TITANOSAUR DIVERSITY FROM CERRO OVERO–LA INVERNADA (SANTONIAN)
87
Figure 9. Sequence of six articulated middle caudal vertebrae and three haemal arches MAU-Pv-LI-600 in 1, lateral; and 2, dorsal views. Scale
bar= 10 cm. Anatomical abbreviations: ha, haemal arch; ns, neural spine; poz, postzigapophysis; prz, prezigapophysis; tp, transverse process.
centrum has a posterior convex condyle, while the anterior
cotyle has not been preserved, which makes it impossible
to establish if the centrum is procoelous, as in Overosaurus,
or if the centrum is biconvex as in the posterior caudal of
Rinconsaurus and Pitekunsaurus. The vertebral centrum is
characterized by being dorsoventrally compressed in pos-
terior view, causing it to be wider than high. The dorsal and
ventral surface of the centrum is practically flat, the ventral
being slightly concave anteroposteriorly in lateral view. The
lateral surfaces of the centrum are dorsoventrally convex
and anteroposteriorly concave. According to the preserved
portion of the base of the neural arch, it would be located
in the anterior half of the vertebral centrum, as seen in
most titanosauriformes (e.g., Rinconsaurus,Muyelensaurus,
Overosaurus,Aeolosaurus,Arrudatitan,Punatitan coughlini;
Hechenleitner et al., 2020).
Comments. The caudal centrum MAU-Pv-CO-668 is
dorsoventrally compressed, a characteristic present in pos-
terior caudal vertebrae of Rinconsaurus (MAU-Pv-CRS-29,
30) and Saltasaurinae (e.g., Neuquensaurus), different from
the proportional (wide as tall) posterior caudal vertebrae of
other titanosaurians (e.g., Malawisaurus, Uberabatitan,
Overosaurus,Pitekunsaurus, and Bonitasaura). One of the
characteristics that define Rinconsauria (Calvo et al., 2007a),
a clade that included Rinconsaurus and Muyelensaurus, is the
presence of posterior caudal vertebrae with posteriorly
compressed centra. Nevertheless, this character cannot be
evaluated, because the anterior portion of the centrum
MAU-Pv-CO-668 is incomplete, although it is inferred that
the centrum would have been compressed dorsoventrally.
Comparisons with other sauropods from Bajo de la Carpa
Formation. With the aim to test the hypothesis of a more
diversified sauropod fauna in the northeastern Neuquén
Basin during the Santonian, we compared the new fossil
evidence from CO – LI locality with the sauropod taxa from
the Bajo de la Carpa Formation. The sauropod fossil record
from Bajo de la Carpa Formation is composed of
Overosaurus and Rinconsaurus, from the northeastern
Neuquén Basin, and Bonitasaura, from the southeastern.
Below, we synthesize the main morphological differences
between the compared specimens, being more detailed in
the similarities in the description section.
Overosaurus was formalized on the basis of an articu-
lated specimen from CO – LI locality (Coria et al., 2013), and
originally described as coming from the Anacleto Formation
but reconsidered as belonging to Bajo de la Carpa Formation
by Filippi et al. (2015). The type material of Overosaurus
(MAU-Pv-CO-439) is composed of 40 articulated vertebrae,
including the last four cervical vertebrae, ten dorsal verte-
brae, six sacral vertebrae, and 20 caudal vertebrae, cervical
and dorsal ribs, complete right ilium and part of the left
one. Thus, considering the overlapping material, we carry
out the morphological comparisons with Overosaurus of the
following new elements: middle-posterior dorsal vertebra
MAU-Pv-CO-671; anterior caudal vertebrae MAU-Pv-LI-
601, 669, 670, and MAU-Pv-CO-407; and middle caudal
vertebrae MAU-Pv-LI-600. As mentioned before, the new
dorsal element MAU-Pv-CO-671 differs from Overosaurus
in lacking the ventral keel of the vertebral centrum, showing
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Figure 10. Incomplete posterior caudal center MAU-Pv-CO-668 in 1,
dorsal; 2, lateral; 3, ventral; and 4, posterior views. Scale bar= 10 cm.
the POSL, presence of a single PCDL without a fossae be-
tween the PCDL and ACDL, and for the medioventral posi-
tion of the CPOL (Fig. 11.1–6). Taking into account the new
anterior caudal vertebrae, MAU-Pv-LI-670 differs from
Overosaurus in the convex ventral surface and the subtrian-
gular posterior surface of the centrum. MAU-Pv-LI-601
shows the dorsal half of the centrum wider than the ventral
one and sinusoidal lateral surfaces of the centrum, unlike in
Overosaurus, where the centrum is quadrangular and the
lateral surface is slightly anteroposteriorly concave. MAU-
Pv-LI-669 has a procoelous-opisthoplatyan centrum and
the dorsal margins of the anterior and posterior articular
surfaces are inclined similar to Traukutitan (Fig. 11.7–8),
whereas Overosaurus caudal vertebra is procoelous and
shows straight anterodorsal and posterodorsal margins
of the centrum. Finally, MAU-Pv-CO-407 differs from
Overosaurus for the concave articular surfaces of the
postzygapophysis.
Other sauropod taxon from the Bajo de la Carpa Forma-
tion is represented by Rinconsaurus, which was originally
described by Calvo & González Riga (2003) as coming from the
Río Neuquén Subgroup (Turonian-Coniancian), but recently
lithostratigraphically reassessed by Filippi et al. (2015). The
Rinconsaurus type material is composed of several cranial
and postcranial elements coming from the proximities of
Rincón de los Sauces city and was partially redescribed by
Moreno et al. (2021, 2022). The morphological comparisons
with Rinconsaurus focused on the following new elements:
teeth (MAU-Pv-LI-645, 646, and MAU-Pv-CO-650); mid-
dle-to-posterior dorsal vertebra MAU-Pv-CO-671; and the
caudal vertebrae MAU-Pv-LI-600, 601, 669, 670, and MAU-
Pv-CO-407, 668, 671. The tooth MAU-Pv-LI-645 differs
from Rinconsaurus teeth for the straight carinae, whereas
MAU-Pv-LI-646 and MAU-Pv-CO-650 lack carinae. The
middle-to-posterior dorsal vertebra MAU-Pv-CO-671
differs from Rinconsaurus due to its distinct configuration of
the lateral laminae and fossae of the centrum and the
presence of prominent TPOL and a ventrally directed single
STPOL. The most anterior new caudal vertebra MAU-Pv-LI-
670 differs from Rinconsaurus in the laterally directed trans-
verse process and for lacking the wide pneumatic lateral
fossa and the slightly convex ventral surface of the centrum.
The anterior caudal vertebra MAU-Pv-CO-407 differs from
Rinconsaurus for the vascular foramina on the lateroventral
surface of the centrum, the presence of the POCDF, for
lacking the hour-glasses morphology of the centrum in
ventral view, and the TPOL ventrally to the postzygapophy-
ses. The caudal vertebra MAU-Pv-LI-601 differs from
Rinconsaurus for lacking the TPRL, as well the hour-glass
morphology of the centrum in ventral view. The new anterior
caudal vertebra MAU-Pv-LI-669 differs from Rinconsaurus
for the procoelous-opithoplatyan articulation of the cen-
trum, the presence of vascular foramina on the lateroventral
surfaces of the centrum, the inclined dorsal margin of the
anterior and posterior articular surfaces of the centrum, and
for lacking the hour-glass morphology of the centrum in
ventral view. Despite some differences (absence of TPRL,
TPOL, and convex dorsal surface of neural spine), the main
morphology of the new middle caudal vertebrae MAU-Pv-
LI-600 resembles the middle caudals of Rinconsaurus and
similar to Overosaurus (Fig. 11.10–12). Indeed, MAU-Pv-LI-
600 have quadrangular centra with strongly procoelous ar-
ticulation and anteroposteriorly concave lateral surfaces
without pneumatic fossae or foramina; moreover, in the
neural arch, there are narrow SPRF and SPOF, framed for
SPRL and SPOL in both specimens. Convergently, the
articulated new caudal elements MAU-Pv-LI-600 show
postzygapophyseal processes, as in other rinconsaurian
(e.g., Rinconsaurus, Pitekunsaurus). Finally, the posterior new
caudal elements MAU-Pv-LI-668 are broadly fragmented
and the comparisons with Rinconsaurus are limited to the
general morphology of the centrum, which seems to be
dorsoventrally compressed in both specimens (Fig. 11.13–14).
The Santonian outcrops of the southeastern Neuquén
Basin (Río Negro Province) yielded the third sauropod taxon
from the Bajo de la Carpa Formation Bonitasaura. It was
described on the basis of cranial and postcranial elements
belonging to a subadult individual, including different bones
of the skull, isolated tooth, axis, three cervical, five dorsal,
and 25 caudal vertebrae, several cervical and dorsal ribs,
five chevrons, a fragment of sternal plate, incomplete
humerus, two metacarpals, pubis, ischium, femur, tibia,
fragmentary fibula, both astragali, and several metatarsals
and phalanges. Considering the overlapping elements, we
compare Bonitasaura type materials with all new specimens.
The new isolated tooth MAU-Pv-LI-645 differs from
FILIPPI ET AL.: TITANOSAUR DIVERSITY FROM CERRO OVERO–LA INVERNADA (SANTONIAN)
89
Bonitasaura in being narrower and cone chisel-like, whereas
the teeth MAU-Pv-LI-646 and MAU-Pv-CO-650 lack of
carinae and hexagonal cross-section of the crown, two mor-
phological conditions seen in Bonitasaura. The new anterior
cervical vertebra MAU-Pv-LI-602 differs from Bonitasaura
for showing a CPOF, a divided CPOL, and for lacking the
constriction of the neural canal. The new middle-to-posterior
dorsal vertebra MAU-Pv-CO-671 differs from Bonitasaura
for the ventrolateral position of the CPOL, the presence of a
single SPOL, and for lacking a wide CPRF and the TPRL. The
most anterior new caudal vertebra MAU-Pv-LI-670 differs
from Bonitasaura for showing pneumatic foramina in the
dorsolateral surface of the centrum and for lacking the
trapezoidal anterior articular surface of the centrum. The
anterior caudal MAU-Pv-CO-407 differs from Bonitasaura
for showing vascular foramina in the lateroventral surfaces
of the centrum, dorsoventrally compressed transverse
process, slightly concave postzygapophysis articular sur-
face, and deep SPOF. The new anterior caudal MAU-Pv-LI-
601 differs from Bonitasaura for the morphology of the
centrum, where the dorsal portion is wider than the ventral
one, and the anterolateral surface is convex. The new ante-
rior caudal MAU-Pv-LI-669 differs from Bonitasaura for the
procoelous-opisthoplatyan articulation of the centrum,
showing vascular foramina on the lateroventral surfaces of
the centrum, and for the inclined dorsal margin of the ante-
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90
Figure 11. Comparative images of axial elements from CO – LI. 1–2, Middle-posterior dorsal vertebra MAU-Pv-CO-671 in 1, lateral; and 2,
posterior views. Middle-posterior dorsal vertebra from Overo saur us in 3, lateral; and 4, posterior views. Posterior dorsal vertebra from
Bonitasaura in 5, lateral; and 6, posterior views. 7–9, Distalmost anterior caudal vertebrae in left lateral view 7, MAU-Pv-LI-669; 8, Traukutitan ;
and 9, Mendozasaurus. 10–12, Middle caudal vertebrae in dorsal view, 10, MAU-Pv-LI-600; 11, Ri nconsauru s; and 12, O verosaur us. 13–16,
Posterior caudal vertebra, 13, MAU-Pv-CO-668, in left lateral and posterior views; 14, R incosau rus, in left lateral and posterior views; 15,
Bonitasaur a in left lateral view; and 16, Ove rosaurus, in lateral view. For anatomical abbreviations, see previous figures. Scale bar= 10 cm.
rior and posterior articular surfaces of the centrum. MAU-
Pv-LI-600 differs from Bonitasaura for showing an incipient
PRSL and the postzygapophyseal process. Finally, the new
posterior caudal vertebrae MAU-Pv-LI-668 differs from
Bonitasaura for the dorsoventrally compressed posterior
half of the centrum (Fig. 11.15).
The resulting comparisons revealed morphological
differences between the new findings and the known
sauropod taxa from Bajo de la Carpa Formation which would
exclude new occurrences of Overosaurus, Rinconsaurus, and
Bonitasaurua from the CO–LI locality. Moreover, none of the
new elements share diagnostic features with the
aforementioned sauropods, which would allow referring
them to any other kind of formalized sauropod taxa.
Indeed, only the new middle caudal vertebrae MAU-Pv-LI-
600 strongly resembles Rinconsaurus, sharing different
morphological features of both centrum and neural arch;
however, among these, the most peculiar is the presence
of the postzygapophyseal process that is considered as a
synapomorphic condition of Rinconsauria and not diag-
nostic of Rinconsaurus. Pending a new, more complete, and
better-preserved specimen, we consider the morphological
differences here recorded as evidence of a more diversified
sauropod fauna in the northeastern Neuquén Basin, at least
during the Santonian.
DISCUSSION
The sauropod dinosaur fauna of the Bajo de la Carpa
Formation has been relatively scarce in the different locali-
ties where it has been founded (Neuquén City, “Cañadón Río
Seco”, Rincón de los Sauces, Sierra Barrosa, and the northern
coast of Los Barreales Lake in Neuquén Province; “La Bonita”
and Cerro Policía in Río Negro Province; Garrido, 2010).
However, the CO – LI area records a remarkable abundance
and diversity of somphospondylans sauropod remains (in
addition to Overosaurus), which include not only different
body sizes but also morphological differences that indicate
the presence of different taxa. Although it is not possible to
establish the ontogenetic stage of the specimens to which
the materials presented here correspond, they show the
presence of small to medium-sized forms (e.g., teeth MAU-
Pv-LI-646 and MAU-Pv-CO-650; anterior cervical vertebrae
MAU-Pv-LI-602) as well as large forms (e.g., tooth MAU-Pv-
LI-645; anterior caudal vertebra MAU-Pv-CO-407). Fur-
thermore, this evidence would allow us to infer that, at least
in this region of Gondwana, a lineage of basal titanosaurs
could have survived even until the end of the Cretaceous, in
contrast to the interpretations made by Leanza et al. (2004)
and Salgado & Bonaparte (2007), where they established
the extinction of the basal titanosaurs before the Santonian.
Taxonomic status of materials from CO – LI
MAU-Pv-LI-645, MAU-Pv-LI-646, and MAU-Pv-CO-
650. These teeth display distinct features indicative of a ti-
tanosaurian phylogenetic signal. Notably, these teeth exhibit
dental crowns with a cross-sectional shape resembling
half-cylindrical crowns, indicating a rounded or semi-circu-
lar profile. The SI values for these dental crowns fall within
the range of 3–5, further confirming their alignment with
titanosaurian dental characteristics. Moreover, the presence
of slightly developed marginal wear facets on these teeth
supports their affinity with titanosaurians. Collectively, these
features strongly suggest the presence of titanosaurian
traits in these teeth, emphasizing their significance within
the broader context of titanosaurian dinosaur paleontology.
MAU-Pv-LI-602. These cervical vertebrae showcase
distinctive characteristics that signify a phylogenetic signal
associated with the Eutitanosauria clade. These traits com-
prise moderately developed parapophyses, which are ven-
trally oriented and result in the displacement of cervical ribs.
Furthermore, there is an absence of pleurocoels in the cer-
vical centra, except in the posteriormost vertebrae. Notably,
a deep lateral fossa with pneumatopores communicating
with internal pneumatic cavities is present. Additionally, the
neural arch lamination is rudimentary, with either absent or
slightly marked diapophyseal laminae. These features
collectively point to the classification of MAU-Pv-LI-602
within the Eutitanosauria clade.
MAU-Pv-CO-671. This dorsal vertebra displays distinct
characteristics that place it within the Eutitanosauria clade.
Notably, key features include the absence of the SPRL in
both anterior and middle dorsal neural spines, as well as the
projection of the anterior edge of the neural spine posteriorly
to the diapophysis in middle dorsal neural arches. Additionally,
there is a slight inclination of both middle and posterior
dorsal neural spines at an angle of approximately 70°. These
FILIPPI ET AL.: TITANOSAUR DIVERSITY FROM CERRO OVERO–LA INVERNADA (SANTONIAN)
91
traits collectively provide a robust phylogenetic signal, firmly
associating MAU-Pv-CO-671 with the Eutitanosauria clade.
MAU-Pv-LI-670. This caudal centrum is characterized
by a markedly convex posterior articular surface and the
absence of ventral protrusions on the transverse process.
Another distinguishing feature of MAU-Pv-LI-670 is the
presence of a lateral pneumatic foramen on the anterior
caudal vertebra. In addition, the shape of the articular face
of the caudal centrum is procoelous. These unique features
contribute to a global understanding of the taxonomic
placement of MAU-Pv-LI-670 within the Somphospondyli
clade.
MAU-Pv-CO-407. This anterior caudal centrum exhibits
a procoelous articular face shape. Furthermore, the shape
of the anterior caudal transverse processes is distinctive,
characterized by a dorsomedially oriented high lateral mar-
gin instead of a vertical tapering distal end. In this anterior
caudal vertebra, there is a noticeable inclination of the an-
terior face strongly forward. The neural arch in this vertebra
displays poorly developed SPOL, resulting in the articular
facet of the postzygapophysis projecting slightly from the
midline. These distinctive traits contribute to the classifica-
tion of MAU-Pv-CO-407 within the Aeolosaurini group and
provide valuable insights into its pylogenetic signal.
MAU-Pv-LI-601. This procoelous anterior caudal cen-
trum has a well-developed SPRL that extends into the an-
terolateral edge of the neural spine. Furthermore, the shape
of the anterior caudal transverse processes is notable, with
a dorsomedially oriented high lateral margin instead of a
distally tapering and vertically oriented one. These dis-
tinctive anatomical traits are indicative of MAU-Pv-LI-601’s
affiliation with Eutitanosauria.
MAU-Pv-LI-669. This anterior caudal centrum exhibits
a procelous-distoplatyan articulation. Additionally, its ven-
tral surface displays a concave transverse configuration.
These features align with the distinctive traits associated
with Somphospondyli.
MAU-Pv-LI-600. These caudal vertebrae stand out due
to its unique anatomical characteristics, including a cylin-
drical mid-caudal centrum and distinctive articular facets of
the prezygapophyses characterized by broad expansions,
both dorsal and ventral. Another noteworthy feature dis-
tinguishing MAU-Pv-LI-600 is the presence of postzy-
gapophyses located in the anterior half of the centrum in
both anterior and middle caudal vertebrae. Particularly in
the middle caudal vertebrae, the SPOL development in the
neural arch is slightly underdeveloped, causing the articular
facet of the postzygapophyses to protrude from the mid-
line. These specific anatomical traits play a crucial role in
classifying MAU-Pv-LI-600 within the Aeolosaurini.
MAU-Pv-LI-668. This posterior caudal vertebra exhibits
distinctive features, including neural arches situated on the
anterior half of the centrum and a dorsoventrally flattened
centrum with a width at least double its height. Moreover,
the apex of the convexity in the posterior joint is concentric,
a defining characteristic that places MAU-Pv-LI-668 within
the Rinconsauria.
CONCLUSIONS
The CO – LI area records the presence of a remarkable
diversity of titanosauriforms sauropod that probably lived
together in the same environment, which can be correlated
with the diversity of the record of abelisaurid theropods
(Filippi et al., 2016; Méndez et al., 2018, 2021; Gianechini et
al., 2021) and chelid turtles (Maniel & De la Fuente, 2017)
that have been found in the same area. This great faunal
diversity is related to a particular paleoenvironmental de-
velopment, for which studies about this (e.g., palynology,
sedimentary) will be necessary in the future, in order to
evaluate the conditions that generated this scenario.
The materials presented here show morphological and
evolutionary variations, which highlight the potentiality of
the area. The discovery of new and more complete speci-
mens to carry paleofaunistic, paleobiological, and paleoeco-
logical studies, will allow a better understanding of the role
of somphospondyli sauropods in the Upper Cretaceous
ecosystems.
ACKNOWLEDGMENTS
We thank the Municipalidad of Rincón de los Sauces, for the
logistical support provided during the fieldwork and the
technicians of the Museo Municipal “Argentino Urquiza” for
preparing the fossil materials. We would like to thank the
editors P. Cruzado-Caballero, B. Cariglino and L.E. Cruz, and
the reviewers V. Díez Díaz and S. Poropat for the corrections
and useful comments that improved the quality of this
contribution. Financial support was provided by the Fondo
para la Investigación Científica y Tecnológica (Foncyt), PICT-
2012-I-INVI-00513 (LSF).
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92
REFERENCES
Alvarenga H. M. F. & Bonaparte, J. F. (1992). A new flightless landbird
from the Cretaceous of Patagonia. Los Angeles County Museum of
Natural History,Science – Series, 36, 51–64.
Apesteguía, S. (2004). Bonitasaura salgadoi gen. et sp. nov.: A break
sauropod from the Late Cretaceous of Patagonia.
Naturwissenchaften,91, 493–497.
Apesteguía, S., Agnolín, F. L., & Claeson, K. (2007). Review of
Cretaceous dipnoans from Argentina (Sarcopterygii, Dipnoi) with
description of new species. Revista del Museo Argentino de
Ciencias Naturales,Nueva Serie,9(1), 27–40.
Barrett, P. M. & Upchurch, P. (2005). Sauropodomorph Diversity
through Time. In K. A. Curry Rogers & J. A. Wilson (Eds.), The
Sauropods: Evolution and Paleobiology(pp. 125–156). University of
California Press.
https://doi.org/10.1525/california/9780520246232.003.0005
Bellardini, F., Windholz, G. J., Baiano, M. A., Garrido, A. C., & Filippi, L.
S. (2021). New titanosaur remains from the Portezuelo
Formation (Turonian–Coniancian) and their implications for the
sauropod faunal diversity of the southern Neuquén Basin,
Patagonia, Argentina. Journal of South American Earth Sciences,
111, 103457.
Bonaparte, J. F. (1991). Los vertebrados fósiles de la Formación Río
Colorado, de la ciudad de Neuquén y cercanías, Cretácico Superior,
Argentina. Revista del Museo Argentino de Ciencias Naturales
Bernardino Rivadavia, 5, 16–124.
Bonaparte, J. F. & Powell, J. E. (1980). A continental assemblage of
tetrapods from the upper cretaceous beds of El Brete, North-
western Argentina (Sauropoda-Coelurosauria-Carnosauria-Aves).
Mémoires de le Société Géologique de France, N. S.,59, 18–28.
Bonaparte, J. F., Riga, B. J. G., & Apesteguía, S. (2006). Ligabuesaurus
leanzai gen. et sp. nov. (Dinosauria, Sauropoda), a new titanosaur
from the Lohan Cura Formation (Aptian, lower Cretaceous) of
Neuquén, Patagonia, Argentina. Cretaceous Research,27(3), 364–
376.
Borsuk-Bialynicka, M. (1977). A new camarasaurid sauropod
Opisthocoelicaudia gen. n. sp. n. from the Upper Cretaceous of
Mongolia. Paleontologia Polonica, 37, 5–64.
Brochu, C. A. (1996). Closure of neurocentral sutures during
crocodilian ontogeny: implications for maturity assessment in
fossil archosaurs. Journal of Vertebrate Paleontology,16, 49–62.
Calvo, J. O. (1994). Feeding mechanism in some sauropod dinosaurs
[Unpublished Master Thesis]. University of Illinois.
Calvo, J. O. & González Riga, B. (2003). Rinconsaurus caudamirus gen.
et sp. nov., a new titanosaurid (Dinosauria, Saurópoda) from the
late Cretaceous of Patagonia, Argentina. Revista Geológica de
Chile, 30(2), 333–353.
Calvo, J. O., González Riga, B. J., & Porfiri, J. (2007a). A new titanosaur
sauropod from Late Cretaceous of Neuquén, Patagonia,
Argentina. Arquivos do Museu Nacional, Rio do Janeiro, 65, 485–
504.
Calvo, J. O., Porfiri, J., González Riga, B. J., & Kellner, A. W. A. (2007b).
A new Cretaceous terrestrial ecosystem from Gondwana with
the description of a new sauropod dinosaur. Anais da Academia
Brasileira de Ciências, 79, 529–541.
Calvo, J. O., Porfiri, J. D., González Riga, B. J., & Kellner, A. W. A. (2007c).
Anatomy of Futalognkosaurus dukei Calvo, Porfiri, González Riga
& Kellner, 2007 (Dinosauria, Titanosauridae) from the Neuquén
Group (Late Cretaceous), Patagonia, Argentina. Arquivos do
Museu Nacional, 65, 511–526.
Campos, D. A., Kellner, A. W. A., Bertini, R. J., & Santucci, R. M. (2005).
On a Titanosaurid (Dinosauria, Sauropoda) vertebral column from
the Bauru group, Late Cretaceous of Brazil. Arquivos do Museu
Nacional, Rio de Janeiro, 63(3), 565–593.
Canudo, J. I., Carballido, J. L., Garrido, A., & Salgado, L. (2018). A new
rebbachisaurid sauropod from the Aptian–Albian, Lower
Cretaceous Rayoso Formation, Neuquén, Argentina. Acta
Palaeontologica Polonica, 63(4), 679–691.
Canudo, J. I., Filippi, L. S., Salgado, L., Garrido, A., Cerda, I., García, R.,
& Otero, A. (2007). Nuevos datos sobre los titanosaurios
(Dinosauria, Sauropoda) de la Formación Plottier (Conaciense–
Santoniense) en Rincón de los Sauces (Neuquén, Patagonia,
Argentina). Cuadernos del Museo Geominero,8, 81–84.
Carballido, J. L., Pol, D., Otero, A., Cerda, I. A., Salgado, L., Garrido, A. C.,
Ramezzani, J., Cúneo, N. R., & Krause, M. J. (2017). A new giant
titanosaur sheds light on body mass evolution among sauropod
dinosaurs. Proceedings of the Royal Society B, 284, 20171219.
http://dx.doi.org/10.1098/rspb.2017.1219
Carballido, J. L., Otero, A., Mannion, P. D., Salgado, L., & Pérez-
Moreno, A. (2022). Titanosauria: A Critical Reappraisal of Its
Systematics and the Relevance of the South American Record. In
A. Otero, J. L. Carballido, & D. Pol (Eds.), South American
Sauropodomorph Dinosaurs (pp. 341–392). Springer Earth System
Sciences. https://doi.org/10.1007/978-3-030-95959-3_8
Chure, D., Britt, B. B., Whitlock, J. A., & Wilson, J. A. (2010). First
com plete sauropod dinosaur skull from the Cretaceous of
the Americas and the evolution of sauropod dentition.
Naturwissenschaften, 97, 379–391.
Coria, R. A., Chiappe, L. M., & Dingus, L. (2002). A new close relative
of Carnotaurus sastrei Bonaparte 1985 (Theropoda:
Abelisauridae) from the Late Cretaceous of Patagonia. Journal of
Vertebrate Paleontology,22, 460–465.
Coria, R. A., Filippi, L. S., Chiappe, L. M., García, R. A., & Arcucci, A. B.
(2013). Overosaurus paradasorum gen. et sp. nov., a new
sauropod dinosaur (Titanosauria: Lithostrotia) from the Late
Cretaceous of Neuquén, Patagonia, Argentina. Zootaxa,3683,
357–376.
Coria, R. A., Ortega, F., Arcucci, A. B., & Currie, P. J. (2019). A new and
complete peirosaurid (Crocodyliformes, Notosuchia) from Sierra
Barrosa (Santonian, Upper Cretaceous) of the Neuquén Basin,
Argentina. Cretaceous Research, 95, 89–105.
Cruzado-Caballero, P., Filippi, L. S, Méndez, A. H., Garrido, A. C., &
Días-Martínez, I. (2018). First ornithopod remains from Bajo de
la Carpa Formation (Santonian, Upper Cretaceous), northern
Patagonia, Argentina. A new view about the biodiversity of Late
Cretaceous South American ornithopods. Cretaceous Research,
83, 182–193.
Cruzado-Caballero, P., Gasca, J. M., Filippi, L. S, Cerda, I. A., & Garrido,
A. C. (2019). A new ornithopod dinosaur from the Santonian of
Northern Patagonia (Rincón de los Sauces, Argentina). Cretaceous
Research, 98, 211–229.
Curry Rogers, K. A. (2009). The postcranial osteology of Rapetosaurus
krausei (Sauropoda: Titanosauria) from the Late Cretaceous of
Madagascar. Journal of Vertebrate Paleontology, 29, 1046–1086.
Curry Rogers, K. & Forster, C. A. (2001). The last of the dinosaur
titans: a new sauropod from Madagascar. Nature,412(6846),
530–534.
De la Fuente, M. S., Calvo, J. O., & González Riga, B. J. (2007). A new
Cretaceous chelid turtle from the northern Neuquén.
Ameghiniana,44(2), 485–492.
De la Fuente, M. S., Maniel, I. J., Janello, M., Filippi, L. S., & Cerda, I.
(2015). Long-necked chelid turtles from the Campanian of
northwestern Patagonia with comments on K/P survivorship of
FILIPPI ET AL.: TITANOSAUR DIVERSITY FROM CERRO OVERO–LA INVERNADA (SANTONIAN)
93
Yaminuechelys lineage. Comptes Rendus Palevol, 14(6–7), 563–576.
D’Emic, M. D. & Wilson, J. A. (2011). New remains attributable to the
holotype of the sauropod dinosaur Neuquensaurus australis, with
implications for saltasaurine systematics. Acta Palaeontologica
Polonica,56(1), 61–73.
Díez Díaz, V., Suberbiola, X. P., & Sanz, J. L. (2013a). The axial skeleton
of the titanosaur Lirainosaurus astibiae (Dinosauria: Sauropoda)
from the latest Cretaceous of Spain. Cretaceous Research, 43,
145–160.
Díez Díaz, V., Tortosa, T., & Le Loeuff, J. (2013b). Diversidad de
saurópodos en el Cretácico Superior del suroeste de Europa: las
lecciones de odontología. Annales de Paléontologie, 99(2), 119–129.
Ezcurra, M. D. & Méndez, A. H. (2009). First report of a derived
abelisaurid theropod from the Bajo de la Carpa Formation (Late
Cretaceous), Patagonia, Argentina. Bulletin of Geosciences,84,
547–554.
Filippi, L. S., Canudo, J. I., Salgado, L., Garrido, A., García, R., Cerda, I., &
Otero, A. (2007). Un nuevo ejemplar de Titanosauria (Saurischia,
Sauropoda) de la Formación Plottier, (Cretácico Superior), Rincón
de los Sauces, Neuquén, Argentina. Ameghiniana, 44, R18.
Filippi, L. S., Canudo, J. I., Salgado, L., Garrido, A., García, R., Cerda, I. A.,
& Otero, A. (2011a). A new sauropod titanosaur from the Plottier
Formation (Upper Cretaceous) of Patagonia (Argentina). Geologica
Acta, 9(1), 1–12.
Filippi, L. S., García, R. A., & Garrido, A. C. (2011b). A new titanosaur
sauropod dinosaur from Upper Cretaceous of North Patagonia,
Argentina. Acta Paleontologica Polonica, 56(3), 505–520.
Filippi, L. S. & Garrido, A. C. (2008). Pitekunsaurus macayai gen. et sp.
nov., nuevo titanosaurio (Saurischia, Sauropoda) del Cretácico
Superior de la Cuenca Neuquina, Argentina. Ameghiniana,45(3),
575–590.
Filippi, L. S., Martinelli, A. G., & Garrido, A. C. (2013). Registro de un
dinosaurio Aeolosaurini (Sauropoda, Titanosauria) en el Cretácico
Superior (Formación Plottier) del Norte de la Provincia de
Neuquén, Argentina, y comentarios sobre los Aeolosaurini
sudamericanos. Revista Brasilera de Paleontología, 16(1), 147–
156.
Filippi, L. S., Martinelli, A. G., & Garrido, A. C. (2015). Una nueva
asociación de dientes de vertebrados para la Formación Bajo de
la Carpa (Santoniense, Cretácico Superior) en Rincón de los
Sauces, Neuquén, Argentina. Spanish Journal of Palaeontology,
30(2), 223–238.
Filippi, L. S., Méndez, A. H., Juárez Valieri, R. D., & Garrido, A. C. (2016).
A new brachyrostran with hypertrophied axial structures reveals
an unexpected radiation of latest Cretaceous abelisaurids.
Cretaceous Research, 61, 209–219.
Filippi, L. S., Barrios, F., & Garrido, A. C. (2018). A new peirosaurid from
the Bajo de la Carpa Formation (Upper Cretaceous, Santonian) of
Cerro Overo, Neuquén, Argentina. Cretaceous Research,83, 75–83.
Filippi, L. S, Salgado, L., & Garrido, A. C. (2019). A new giant basal
titanosaur sauropod in the Upper Cretaceous (Coniacian) of the
Neuquén Basin, Argentina. Cretaceous Research, 100, 61–81.
Fiorelli, L. & Calvo, J. O. (2007). The first “Protosuchian” (Archosauria:
Crocodyliformes) from the Cretaceous (Santonian) of Gondwana.
Arquivos do Museu Nacional Rio de Janeiro, 65(4), 417–459.
Franco-Rosas, A. C., Salgado, L., Rosas, C. F., & Carvalho, I. S. (2004).
Nuevos materiales de titanosaurios (Sauropoda) en el Cretácico
Superior de Mato Grosso, Brasil. Revista Brasileira de Paleontologia,
7, 329–336.
Gallina, P. A. & Apesteguía S. (2011). Cranial anatomy and
phylogenetic position of the titanosaurian sauropod Bonitasaura
salgadoi. Acta Palaeontologica Polonica, 56(1), 45–60.
Gallina, P. A. & Apesteguía, S. (2015). Postcranial anatomy of
Bonitasaura salgadoi (Sauropoda, Titanosauria) from the Late
Cretaceous of Patagonia. Journal of Vertebrate Paleontology, 35(3),
e924957. https://doi.org/10.1080/02724634.2014.924957
Gallina, P. A. & Otero, A. (2015). Reassessment of Laplatasaurus
araukanicus (Sauropoda: Titanosauria) from the Upper Cretaceous
of Patagonia, Argentina. Ameghiniana, 52, 487–501.
Gallina, P. A., Canale, J. I., & Carballido, J. L. (2021). The earliest known
titanosaur sauropod dinosaur. Ameghiniana,58(1), 35–51.
Gallup, M. R. (1989). Functional morphology of the hindfoot of the
Texas sauropod Pleurocoelus sp. indet. Geological Society of
America, Special Paper,238, 71–74.
García, R. A. & Cerda, I. A. (2010). Dentición de titanosaurios
(Dinosauria, Sauropoda) del Cretácico Superior de la provincia de
Río Negro, Argentina: morfología, inserción y reemplazo.
Ameghiniana, 47(1), 45–60.
Garrido, A. C. (2010). Estratigrafía del Grupo Neuquén: Cretácico
superior de Cuenca Neuquina: nueva propuesta de ordenamiento
litoestratigráfico. Revista del Museo Argentino de Ciencias Naturales,
12, 121–177.
Gasparini, Z. B., Chiappe, L., & Fernández, M. (1991). A new Senonian
peirosaurid (Crocodylomorpha) from Argentina and a synopsis of
the South American Cretaceous crocodilians. Journal of Vertebrate
Paleontology, 11, 316e333.
Gianechini, F. A., Lio, G., & Apesteguía, S. (2011). Isolated
archosaurian teeth from “La Bonita” locality (Late Cretaceous,
Santonian-Campanian), Río Negro province, Argentina. Historia
Natural, 1, 5–16.
Gianechini, F. A., Méndez, A. H., Filippi, L. S., Paulina-Carabajal, A.,
Juárez-Valieri, R. D., & Garrido, A. C. (2021). A new furileusaurian
abelisaurid from La Invernada (Upper Cretaceous, Santonian,
Bajo de la Carpa Formation), northern Patagonia, Argentina.
Journal of Vertebrate Paleontology, 40(6),e1877151.
https://doi.org/10.1080/02724634.2020.1877151
Gilmore, C. W. (1922). A new sauropod dinosaur from the Ojo Alamo
Formation of New Mexico. Smithsonian Miscellaneous Collections,
72, 19.
Gilmore, C. W. (1946). Reptilian fauna from the North Horn Formation
of central Utah. United States Geological Survey Professional Paper,
210, 29–52.
Gomani, E. M. (2005). Sauropod dinosaurs from the Early Cretaceous
of Malawi, Africa. Palaeontologia Electronica, 8, 1–37.
González Riga, B. J. (2003). A new titanosaur (Dinosauria, Sauropoda)
from the Upper Cretaceous of Mendoza Province, Argentina.
Ameghiniana, 40, 155–172.
González Riga, B. J. (2005). Nuevos restos fósiles de Mendozasaurus
neguyelap (Sauropoda, Titanosauria) del Cretácico tardío de
Mendoza, Argentina. Ameghiniana,42, 535–548.
González Riga, B. J., Calvo, J. O., & Porfiri, J. (2008). An articulated
titanosaur from Patagonia (Argentina): New evidence of
neosauropod pedal evolution. Palaeoworld,17, 33–40.
González Riga, B. J., Previtera, E., & Pirrone, C. A. (2009).
Malarguesaurus florenciae gen. et sp. nov., a new titanosauriform
(Dinosauria, Sauropoda) from the Upper Cretaceous of Mendoza,
Argentina. Cretaceous Research,30(1), 135–148.
González Riga, B. J. & Ortiz, L. (2014). A new titanosaur (Dinosauria,
Sauropoda) from the Upper Cretaceous (Cerro Lisandro
Formation) of Mendoza Province, Argentina. Ameghiniana, 51(1),
3–25.
Gorscak, E., O’Connor, P. M., Stevens, N. J., & Roberts, E. M. (2014).
Publicación Electrónica - 2024 - Volumen 24(1): 71–96
94
The basal titanosaurian Rukwatitan bisepultus (Dinosauria,
Sauropoda) from the middle Cretaceous Galula Formation,
Rukwa Rift Basin, southwestern Tanzania. Journal of Vertebrate
Paleontology,34(5), 1133–1154.
Hechenleitner, E. M., Leuzinger, L., Martinelli. A. G., Rocher, S., Fiorelli,
L. E., Taborda, J. R. A., & Salgado, L. (2020). Two Late Cretaceous
sauropods reveal titanosaurian dispersal across South America.
Communications Biology,3, 622.
Hocknull, S. A., White, M. A., Tischler, T. R., Cook, A. G., Calleja, N. D.,
Sloan, T., & Elliott, D. A. (2009). New mid-Cretaceous (latest
Albian) dinosaurs from Winton, Queensland, Australia. PloS One,
4(7), e6190.
Huene, F. von. (1929). Los Saurisquios y Ornitisquios del Cretácico
Argentino. Anales del Museo de La Plata, 2° Serie,3, 1–196.
Jain, S. L. & Bandyopadhyay, S. (1997). New titanosaurid (Dinosauria:
sauropoda) from the Late Cretaceous of central India. Journal of
Vertebrate Paleontology, 17(1), 114–136.
Janensch, W. (1947). Pneumatizität bei Wirbeln von Sauropoden und
anderen Saurischiern. Palaeontographica-Supplementbände, 1–25.
Juárez Valieri, R. D. & Calvo, J. O. (2011). Revision of MUCPv 204, a
Senonian basal titanosaur from northern Patagonia. In J. O. Calvo,
J. D. Porfiri, B. J. González Riga, & D. D. Dos Santos (Eds.),
Paleontología y dinosaurios desde América Latina (pp. 143–152).
Editorial de la Universidad Nacional de Cuyo.
Kellner, A. W. & Azevedo, S. A. (1999). A new sauropod dinosaur
(Titanosauria) from the Late Cretaceous of Brazil. Proceedings of
the Second Gondwanan Dinosaur Symposium, National Science
Museum Monographs,15, 111–142.
Kellner A. W., Campos D. D. A., & Trotta M. N. F. (2005). Description
of a titanosaurid caudal series from the Bauru Group, Late
Cretaceous of Brazil. Arquivos do Museu Nacional,63(3), 529–564.
Ksepka, D. T. & Norell, M. A. (2006). Erketu ellisoni, a long-necked
sauropod from Bor Guvé (Dornogov Aimag, Mongolia). American
Museum Novitates,3508, 1–16.
Lapparent de Broin, F. D. E. & de la Fuente, M. S. (2001). Oldest world
Chelidae (Chelonii, Pleurodira), from the Cretaceous of Patagonia,
Argentina. Sciences de la Terre et des planètes,333, 463–470.
Leanza, H. A., Apesteguía, S., Novas, F. E., & De la Fuente, M. S.
(2004). Cretaceous terrestrial beds from the Neuquén basin
(Argentina) and their tetrapod assemblages. Cretaceous Research,
25(1), 1–96.
Leanza, H. A. & Hugo, C. A. (2001). Cretaceous red beds from
southern Neuquén Basin (Argentina): age, distribution and
stratigraphic discontinuities. Publicación Especial de la Asociación
Paleontológica Argentina, 7, 117–122.
Legarreta, L. & Gulisano, C. A. (1989). Análisis estratigráfico
secuencial de la Cuenca Neuquina (Triásico superior – Terciario
inferior). In G. Chebli & L. Spalletti (Eds.), Cuencas Sedimentarias
Argentinas (pp. 221–243). Facultad de Ciencias Naturales e
Instituto Miguel Lillo.
Lío, G., Agnolín, F. L., Martinelli, A. G., Ezcurra, M. D., & Novas, F. E.
(2018). New specimen of the enigmatic, Late Cretaceous
crocodyliform Neuquensuchus universitas sheds light on the
anatomy of the species. Cretaceous Research, 83, 62–74.
Lydekker, R. (1893). Contributions to the study of the fossil
vertebrates of Argentina. I, the dinosaurs of Patagonia. Anales
del Museo de La Plata, Paleontología, 2, 1–14.
Machado, E. B., Dos S. Avilla, L., Nava, W. R., De A. Campos, D., &
Kellner, A. W. A. (2013). A new titanosaur sauropod from the Late
Cretaceous of Brazil. Zootaxa, 3701(3), 301–321.
Maniel, I. J. & De la Fuente, M. S. (2017). Diversidad de tortugas
Pleurodiras de las formaciones Bajo de la Carpa y Anacleto en
el área de La Invernada, Provincia de Neuquén. Ameghiniana,
54(6), R8.
Marsh, O. C. (1878). Principal characters of American Jurassic
dinosaurs, Part I. American Journal of Science, 16, 411–416.
Martinelli, A. G. & Vera, E. I. (2007). Achillesaurus manazzonei, a new
alvarezsaurid theropod (Dinosauria) from the Late Cretaceous
Bajo de la Carpa Formation, Río Negro Province, Argentina.
Zootaxa,1582, 1–17.
Martinelli, A. G. & Pais, D. F. (2008). A new baurusuchid crocodyliform
(Archosauria) from the Late Cretaceous of Patagonia (Argentina).
Comptes Rendus Palevol, 7(6), 371–381.
Martinelli, A. G., Sertich, J. J. W., Garrido, A. C., & Praderio, Á. M. (2012).
A new peirosaurid from the Upper Cretaceous of Argentina:
Implications for specimens referred to Peirosaurus torminni Price
(Crocodyliformes: Peirosauridae). Cretaceous Research, 37, 191–
200.
Martínez, R. D. F., Giménez, O., Rodríguez, J., Luna, M., & Lamanna,
M. C. (2004). An articulated specimen of the basal titanosaurian
(Dinosauria: Sauropoda) Epachthosaurus sciuttoi from the Early
Late Cretaceous Bajo Barreal Formation of Chubut Province,
Argentina. Journal of Vertebrate Paleontology, 24(1), 107–120.
Martínez, R. D. F., Lamanna, M. C., Novas, F. E., Ridgely, R. C., Casal,
G. A., & Martínez, J. E. (2016). A basal Lithostrotian Titanosaur
(Dinosauria: Sauropoda) with a complete skull: Implications for
the evolution and paleobiology of Titanosauria. PloS ONE, 11(4),
e0151661.
Méndez, A. H., Filippi, L. S., & Garrido, A. C. (2015). Nuevos hallazgos
de dinosaurios terópodos provenientes del sitio La Invernada
(Formación Bajo de la Carpa), Rincón de los Sauces, Neuquén.
Ameghiniana, 52(4), R28–R29.
Méndez, A. H., Filippi, L. S, Juárez Valieri, R. D., & Gianechini, F. A.
(2018). A New Brachyrostran Remains (Theropoda,
Abelisauridae) from La Invernada fossil fite (Bajo de La Carpa
Formation, Late Cretaceous), Northern Patagonia, Argentina.
Cretaceous Research, 83, 120–126.
Méndez, A. H., Gianechini, F. A., Paulina-Carabajal, A., Filippi, L. S.,
Juárez Valieri, R. D., Cerda, I. A., & Garrido, A. C. (2021). New
furileusaurian remains from La Invernada (northern Patagonia,
Argentina): A site of unusual abelisaurids abundance. Cretaceous
Research, 129,104989.
McIntosh, J. S. (1990). Sauropoda. In D. Weishampel, P. Dodson, & H.
Osmólska (Eds.), The Dinosauria (pp. 345–401). University of
California Press.
Nowinski, A. (1971). Nemegtosaurus mongoliensis n. gen., n. sp.,
(Sauropoda) from the uppermost Cretaceous of Mongolia.
Palaeontologica Polonica, 25, 57–81.
Otero, A., Gallina, P. A., Canale, J. I., & Haluza, A. (2011). Sauropod
haemal arches: morphotypes, new classification, and phylogenetic
aspects. Historical Biology,24(3), 243–256.
Panzeri, K. M., Gouiric-Cavalli, S., Cione, A. L., & Filippi, L. S. (2022).
Description of the first Cretaceous (Santonian) articulated
skeletal lungfish remains from South America (Rinconodus
salvadori n. gen., n. sp., Dipnoi, Ceratodontidae; Argentina).
Comptes Rendus Palevol, 21(37), 815–835.
Pérez–Moreno, A., Carballido, J. L., Otero, A., Salgado, L., & Calvo, J. O.
(2022). The Axial Skeleton of Rinconsaurus caudamirus (Sauropoda:
Titanosauria) from the Late Cretaceous of Patagonia, Argentina.
Ameghiniana,59(1), 1–46.
Porfiri, J. D., Juárez Valieri, R. D., Santos, D. D. D., & Lamanna, M. C.
(2018). A new megaraptoran theropod dinosaur from the Upper
FILIPPI ET AL.: TITANOSAUR DIVERSITY FROM CERRO OVERO–LA INVERNADA (SANTONIAN)
95
Cretaceous Bajo de la Carpa Formation of northwestern
Patagonia. Cretaceous Research,89, 302–319.
Poropat, S. F., Frauenfelder, T. G., Mannion, P. D., Rigby, S. L.,
Pentland, A. H., Sloan, T., & Elliott, D. A. (2022). Sauropod
dinosaur teeth from the lower Upper Cretaceous Winton
Formation of Queensland, Australia and the global record of early
titanosauriforms. Royal Society Open Science, 9(7),220381.
Poropat, S. F., Mannion, P. D., Rigby, S. L., Duncan, R. J., Pentland, A.
H., Bevitt, J. J., & Elliott, D. A. (2023). A nearly complete skull of
the sauropod dinosaur Diamantinasaurus matildae from the
Upper Cretaceous Winton Formation of Australia and
implications for the early evolution of titanosaurs. Royal Society
Open Science,10(4),221618.
Powell, J. E. (1987). The Late Cretaceous Fauna from Los Alamitos,
Patagonia, Argentina. Part. VI. The titanosaurids. Revista Museo
Argentino Ciencias Naturales,3(3), 147–153.
Powell, J. E. (1992). Osteología de Saltasaurus loricatus (Saurópoda-
Titanosauridae) del Cretácico Superior del Noroeste argentino. In
J. L. Sanz & A. D. Buscalioni (Eds.), Los Dinosaurios y su entorno
Biótico (pp. 165–230). Instituto “Juan de Valdes”.
Salgado, L., Apesteguía, S., & Heredia, S. E. (2005). A new specimen of
Neuquensaurus australis, a Late Cretaceous Saltasaurine titanosaur
from North Patagonia. Journal of Vertebrate Paleontology,25(3),
623–634.
Salgado, L. & Bonaparte, J. F. (2007). Sauropodomorpha. In Z.
Gasparini, L. Salgado, & R. A. Coria (Eds.), Patagonian Mesozoic
Reptiles (pp. 188–288). Indiana University Press.
Salgado, L. & Coria, R. A. (1993). El género Aeolosaurus (Sauropoda-
Titanosauridae) en la Formación Allen(Campaniano – Maastrichtiano)
de la Provincia de Río Negro, Argentina. Ameghiniana, 30, 119–
128.
Salgado, L. & de Souza Carvalho, I. (2008). Uberabatitan ribeiroi, a new
titanosaur from the Marília Formation (Bauru Group, Upper
Cretaceous), Minas Gerais, Brazil. Palaeontology, 51(4), 881–901.
Santucci, R. M. & Arruda-Campos, A. D. (2011). A new sauropod
(Macronaria, Titanosauria) from the Adamantina Formation,
Bauru Group, Upper Cretaceous of Brazil and the phylogenetic
relationships of Aeolosaurini. Zootaxa,3085(1), 1–33.
Santucci, R. M. & Bertini, R. J. (2006). A new titanosaur from western
Sao Paulo State, Upper Cretaceous Bauru Group, South-East
Brazil. Palaeontology,49(1), 59–66.
Sanz, J. L., Powell, J. E., Le Loeuff, J., Martínez, R., & Pereda-
Suberbiola, X. (1999). Sauropod remains from the Upper
Cretaceous of Laño (Northcentral Spain), titanosaur phylogenetic
relationships. Estudios del Museo de Ciencias Naturales de Álava,
14(1), 235–255.
Sereno, P. C., Beck, A. L., Dutheil, D. B., Larsson, H. C. E., Lyon, G. H.,
Moussa, B., Sadlier, R. W., Sidor, C. A., Varricchio, D. J., Wilson, G.
P., & Wilson, J. A. (1999). Cretaceous sauropods from the Sahara
and the uneven rate of skeletal evolution among dinosaurs.
Science, 286, 1342–1347.
Sereno P. C., Martinez R. N., Wilson J. A., Varricchio D. J., Alcober O. A.,
& Larsson, H. C. E. (2008). Evidence for Avian Intrathoracic Air
Sacs in a New Predatory Dinosaur from Argentina. PLoS One,3(9),
1–20.
Silva Junior, J. C. G., Marinho, T. S., Martinelli, A. G., & Langer, M. C.
(2019). Osteology and systematics of Uberabatitan ribeiroi
(Dinosauria; Sauropoda): a Late Cretaceous titanosaur from
Minas Gerais, Brazil. Zootaxa,4577(3), 401–438.
Silva Junior, J. C. G., Martinelli, A. G., Iori, F. V., Marinho, T. S.,
Hechenleitner, M. E., & Langer, M. C. (2021). Reassessment of
Aeolosaurus maximus, a titanosaur dinosaur from the Late
Cretaceous of Southeastern Brazil. Historical Biology,34(3), 403–
411. https://doi.org/10.1080/08912963.2021.1920016
Smith-Woodward, A. S. (1896). On Two Mesozoic Crocodilians
Notosuchus (Genus Novum) and Cynodontosuchus (Genus Novum)
from the Red Sandstone of the Territory of Neuquen (Argentine
Republic). Anales del Museuo de la Plata,6, 1–20.
Smith-Woodward, A. S. (1901). On some extinct reptiles from
Patagonia of the genera Miolania, Dinilysia, and Genyodectes.
Proceedings of the Zoological Society of London, 1901, 169–184.
Tidwell, V., Carpenter, K., & Meyer, S. (2001). New Titanosariform
(Sauropoda) from the poison strip member of the cedar
mountain formation (Lower Cretaceous), Utah. In D. Tank & K.
Carpenter (Eds.), Mesozoic Vertebrate Life (pp. 139–165). Indiana
University Press.
Turner, A. H. & Calvo, J. O. (2005). A new sebecosuchian crocodyliform
from the Late Cretaceous of Patagonia. Journal of Vertebrate
Paleontology, 25, 87–98.
Ullmann, P. V. & Lacovara, K. J. (2016). Appendicular osteology of
Dreadnoughtus schrani, a giant titanosaurian (Sauropoda,
Titanosauria) from the Upper Cretaceous of Patagonia,
Argentina. Journal of Vertebrate Paleontology, 36(6),e1225303.
https://doi.org/10.1080/02724634.2016.1225303.
Upchurch, P. (1998). The phylogenetic relationships of sauropod
dinosaurs. Zoological Journal of the Linnean Society, 124(1), 43–
103.
Vila, B., Sellés, A., Moreno-Azanza, M., Razzolini, N. L., Gil-Delgado, A.,
Canudo, J. I., & Galobart, A. (2022). A titanosaurian sauropod with
Gondwanan affinities in the latest Cretaceous of Europe. Nature,
Ecology and Evolution, 6, 288–296.
https://doi.org/10.1038/s41559-021-01651-5.
Wilson, J. A. (1999). A nomenclature for vertebral laminae in
sauropods and other saurischian dinosaurs. Journal of Vertebrate
Paleontology, 19(4), 639–653.
Wilson, J. A. (2006). Anatomical nomenclature of fossil vertebrates:
standardized terms or ‘lingua franca’? Journal of Vertebrate
Paleontology, 26(3), 511–518.
Wilson, J. A., D’Emic, M. D., Ikejiri, T., Moacdieh, E. M., & Whitlock, J. A.
(2011). A nomenclature for vertebral fossae in sauropods and
other saurischian dinosaurs. PLoS One, 6(2),e17114.
Wilson, J. A. & Sereno, P. C. (1998). Early evolution and higher‐level
phylogeny of sauropod dinosaurs. Society of Vertebrate
Paleontology Memoir, 5, 1–68.
Wilson, J. A., Martínez, R. N., & Alcober, O. (1999). Distal tail segment of
a Titanosaur (Dinosauria: Sauropoda) from the Upper Cretaceous of
Mendoza, Argentina. Journal of Vertebrate Paleontology, 19, 591–
594.
Zaher, H., Pol, D., Carvalho, A. B., Nascimento, P. M., Riccomini, C.,
Larson, P., & de Almeida Campos, D. (2011). A complete skull of
an Early Cretaceous sauropod and the evolution of advanced
titanosaurians. PLoS One, 6(2),e16663.
doi: 10.5710/PEAPA/24.02.2024.484
Recibido: 21 de agosto 2023
Aceptado: 24 de febrero 2024
Publicado: 27 de marzo 2024
Publicación Electrónica - 2024 - Volumen 24(1): 71–96
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