On the presence of plesiosaurs in the Blesa Formation (Barremian) in Teruel (Spain)

Abstract

We describe the first plesiosaurian remains of Barremian age from the Iberian Peninsula. The fossils come from several sites in the Blesa Formation in Teruel (Spain). The recovered material consists of two teeth and nine vertebrae (four cervical, one pectoral, one dorsal, one sacral and two caudal), collected from levels associated with oyster packstone, related to coastal environments. These fossils show the presence of at least one plesiosaurian taxon in the Barremian Iberian coasts. They are the oldest remains described for the Cretaceous of the Iberian Peninsula. Early Cretaceous plesiosaurs are scarce worldwide. Therefore this discovery is of great interest in establishing the Blesa Formation as one of the few sites where Barremian plesiosaur fossils have been found.

Full text

On the presence of plesiosaurs in the Blesa Formation (Barremian) in
Teruel (Spain)
Jara Parrilla-Bel and José Ignacio Canudo
With 6 figures and 2 tables
Abstract: We describe the first plesiosaurian remains of Barremian age from the Iberian Peninsula.
The fossils come from several sites in the Blesa Formation in Teruel (Spain). The recovered material
consists of two teeth and nine vertebrae (four cervical, one pectoral, one dorsal, one sacral and two
caudal), collected from levels associated with oyster packstone, related to coastal environments. These
fossils show the presence of at least one plesiosaurian taxon in the Barremian Iberian coasts. They are
the oldest remains described for the Cretaceous of the Iberian Peninsula. Early Cretaceous plesiosaurs
are scarce worldwide. Therefore this discovery is of great interest in establishing the Blesa Formation
as one of the few sites where Barremian plesiosaur fossils have been found.
Key words: Blesa Formation, Barremian, Plesiosauria, Teruel, Spain, vertebra.
1. Introduction
Plesiosaurs are a clade of aquatic reptiles that appeared
in the Late Triassic and survived until the end of the
Cretaceous (B
akker
1993; G
asparini
et al. 2003; s
enni
-
kov
& a
rkhanGelsky
2010; v
incent
et al. 2011), achie-
ving a global distribution during this period of time
(e.g., B
enson
et al. 2010; B
ardet
et al. 2014). They are a
group of Mesozoic, secondarily aquatic reptiles, totally
adapted to life in water. They possess a streamlined
body outline, all four limbs modified to form large hy-
drofoil-like flippers, and a short tail, in some species
with a small caudal fin (e.g., ketchum & smith 2010;
smith 2013). The size of the head and the length of the
neck vary greatly within the group, with large-headed,
short-necked forms (“pliosauromorphs”); small-hea-
ded, long-necked forms (“plesiosauromorphs”); and
intermediate morphologies between the two extreme
forms (o’keefe 2002). The body size and the feeding
preferences (inferred from skull, tooth morphology and
fossilized gut contents) are also variable within Plesio-
sauria (e.g., massare 198 7; Bardet et al. 2003). Plesi-
osauria is considered to be one of the most successful
groups of aquatic vertebrates and it shows great taxo-
nomic diversity (ketchum & Benson 2010).
The Jurassic-Cretaceous boundary has commonly
been proposed as an extinction interval (B
akker
1993;
Benson et al. 2010) that could have significantly in-
fluenced the evolution of Mesozoic marine reptiles. It
seems that this extinction event did not affect plesio-
saurs as they remained taxonomically and ecologically
diverse and geographically widespread up to their final
extinction at the end of the Cretaceous (vincent et al.
2011, 2013b; Bardet et al. 2014). Although no single,
abrupt episode of near-simultaneous lineage extinction
can be identified at this boundary, however, there is a
substantial turnover of marine reptile faunas over an
extended interval (Benson & druckenmiller 2 014).
While Jurassic plesiosaurians were especially abundant
in Europe, “middle” and Late Cretaceous plesiosauri-
©2015 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany www.schweizerbart.de
DOI: 10.1127/njgpa/2015/0526 0077-7749/2015/0526 $ 3.75
N. Jb. Geol. Paläont. Abh. 278/2 (2015), 213–227 Article
Stuttgart, November 2015
E
eschweizerbart_xxx

214 J. Parrilla-Bel and J.I. Canudo
ans appear in America primarily, but also in Africa,
Australia and New Zealand (e.g., lazo & cichowolski
20 03; Gasparini et al. 2007). Only a few plesiosaurian
lineages crossed the Jurassic-Cretaceous boundary and
diversified from the Early Cretaceous until the Late
Cretaceous. The number of plesiosaurians known from
the Early Cretaceous remains low worldwide (Benson
et al. 2010). These scarce remains come from the Uni-
ted Kingdom, Germany, Russia, South Africa, Austra-
lia, Colombia, the United States and Canada (Table 1;
Bardet et al. 2014, and references therein).
Early Cretaceous plesiosaurians from the Iberian
Peninsula are described only in Spain, specifically in
the Barremian and the Albian outcrops of Teruel and
Castellón provinces (B
ardet
et al. 2008). This period of
time, particularly the Barremian of the Iberian Range
in Teruel, is a singularly rich period in terms of verte-
brate remains (r
uiz
-o
meñaca
et al. 2004; c
anudo
et al.
2010), but marine reptiles from this age are practically
unknown. yaGüe et al. (2003) describe some vertebrae
assigned to Plesiosauria indet. and Elasmosauridae in-
det., and two plesiosaurian teeth from the Aptian of
Morella (Castellón province), one of them belonging
to Elasmosauridae indet. and the other assigned to
Polyptychodon and later identified as belonging to a
baryonychine theropod dinosaur (canudo et al. 2008).
santos-cuBedo et al. (2007) cited a sacral vertebra
from the Aptian of Todolella (Castellón), subsequently
Table 1. List of Early Cretaceous plesiosaurians. Modified from Bardet et al. (2014).
Taxon Stage Location References
Eromangasaurus Albian Australia (Queensland) kear (2005a)
Wapuskanectes Albian Canada (Alberta) druckenmiller & russell (2006)
Nichollssaura Albian Canada (Alberta) druckenmiller & russell (2 0 0 8b)
Edgarosaurus Albian USA (Montana) druckenmiller (20 02)
Kronosaurus Albian Australia (Queensland) kear (2 0 05b)
Umoonasaurus Aptian Australia (Northern South) kear et al. (2006)
Kronosaurus Aptian Australia (New South Wales); Colombia lonGman (1924); hampe (1992)
Callawayasaurus Aptian Boyaca, Colombia welles (1962)
Vectocleidus Barremian United Kingdom Benson et al. (2012)
Brachauchenius Barremian Boyaca, Colombia hampe (2 005)
Leptocleidus Barremian United Kingdom andrews (1922)
Abyssosaurus Hauterivian Russia (Chuvashia) Berezin (2011)
Leptocleidus Hauterivian Western Australia cruickshank & lonG (1997)
Hastanectes Valanginian Germany; United Kingdom ketchum (2011); lydekker (18 89)
Leptocleidus Valanginian South Africa andrews (1911)
Brancasaurus Berriasian Germany weGner (1914)
Table 2. List of Lower Cretaceous plesiosaurian remains from the Iberian Peninsula.
Taxon Referred material Stage Location References
Plesiosauria indet.
Elasmosauridae
indet.
Vertebrae (CMP3/110;
CMP3/635; CMP3/636)
Vertebra (CMX/109095);
Tooth (CMP3/1132)
Aptian Morella (Castellón) yaGüe et al. (2003)
Plesiosauria indet. Sacral vertebra
(MR-To-2003-1) Aptian Todolella (Castellón) santos-cuBedo et al. (2007);
Jorquera Grau et al. (20 09)
Pliosauridae indet. Cervical vertebra
(C P T-3 298)
Albian-
Cenomanian Jabaloyas (Teruel) royo-torres & coBos (2008)
Plesiosauria indet. Indeterminate remains Barremian Galve, Castellote, Las Parras
de Castellote (Teruel) ruiz-omeñaca (20 06)
eschweizerbart_xxx

On the presence of plesiosaurs in the Blesa Formation (Barremian) in Teruel (Spain) 215
described by Jorquera Grau et al. (2009) and assigned
to Plesiosauria indet., and r
oyo
-t
orres
& c
oBos
(2008)
described a pliosaurid cervical vertebra from the Albi-
an-Cenomanian of Jabaloyas (Teruel). Barremian ple-
siosaurian fossils have only previously been cited by
Bardet et al. (2008) and ruiz-omeñaca (2006), who
mentioned indeterminate remains from Galve, Castel-
lote and Las Parras de Castellote (Teruel, Spain). How-
ever, this material has never been figured or described
(Table 2). In the present paper we describe for the first
time some plesiosaur vertebrae and teeth from several
sites from the Blesa Formation (Barremian).
2. Geographical and geological setting
The plesiosaurian fossils studied in this paper have
been found in several fossiliferous sites from Obón
and Josa (Teruel province, Spain). These villages are
located in the northeast of the Iberian Peninsula (Ibe-
rian Range) (Fig. 1A).
The Iberian basin of northeast Spain is an intracra-
tonic basin that developed during the Mesozoic exten-
sion (salas et al. 2001). During the Early Cretaceous,
major extensional tectonic activity took place, which
resulted several areas of subsidence across the Iberian
Fig. 1. Geographical and geological location of the main sites with plesiosaurian remains in the Blesa Formation (Barremian).
a) Geological map of the Iberian Peninsula. b) Location of the palaeogeographic subbasins (Ol: Oliete, Pa: Las Parras, Ga:
Galve, Mo: Morella; Pe: Perelló; Sa: Salzedella, Pg: Peñagolosa) within the Maestrazgo Basin (modified from canudo et al.
2010). c) Location of the main sites within the Blesa Formation where plesiosaurian fossils have been found: 1- Cortes de
Aragón; 2- La Fontanilla 2 and 3; 3- Camino Cabra; 4- La Cantalera 4; 5- Cabra Paridera; 6- Los Quiñones.
eschweizerbart_xxx

216 J. Parrilla-Bel and J.I. Canudo
basin, including the Oliete subbasin within the large
Cretaceous Maestrazgo basin (soria de miGuel 1997;
s
alas
et al. 2001) (Fig. 1B). In the Maestrazgo basin,
the Late Jurassic-Early Cretaceous syn-rift depositio-
nal system was characterized by a predominance of
shallow marine carbonates that gave way only during
the earliest Aptian and Albian to deltaic clastics. The
onset of rifting coincided with a significant rise in sea
level (salas et al. 2001).
The Blesa Formation (Barremian) has a complex
sedimentary evolution (s
oria
de
m
iGuel
1997; a
urell
et al. 2004). The lower part is formed by continental se-
diments from alluvial and lake systems with abundant
continental vertebrate remains (canudo et al. 2010).
The upper part was deposited in coastal and transitio-
nal environments (lagoons, marshlands) (aurell et al.
2004). The plesiosaurian fossils have been collected
from the lower part of the Upper Blesa Formation in
different localities (Fig. 1C). Possibly all the remains
come from the Miembro Calizas de Morenillo (s
or
-
ia de miGuel 1997). This author described the great
diversity of facies typical of eulittoral lacustrine and
coastal systems, usually with low energy. The plesi-
osaurian fossils occur in tabular-bedded oyster pack-
stones with irregular bases. In these oyster-rich levels,
isolated vertebrate remains are abundant, especially
Osteichthyes teeth. Chelonian plates and postcranial
elements from crocodylomorphs and dinosaurs are also
found, although more scarcely. Recently, the presence
of an ornithocheirid pterosaur (u
lloa
-r
ivas
& c
anudo
2014) and a possible metriorhynchid crocodilomorph
(parrilla-Bel et al. 2012) has been cited.
3. Material and methods
The remains reported here are isolated and fragmentary
fossils which come from several sites of the lower Barremian
in the Iberian Range (Fig. 1c): Cortes de Aragón (MPZ
2013/396), La Fontanilla 2 (MPZ 2013/398, MPZ 2013/399),
La Fontanilla 3 (MPZ 2013/407), Camino Cabra (MPZ
2013/400), La Cantalera 4 (MPZ 2013/401, MPZ 2013/402),
Cabra Paridera (MPZ 2013/403), Los Quiñones (MPZ
2013/404, MPZ 2013/405) and Blesa (MPZ 2013/406). The
fossils are housed at the Museo de Ciencias Naturales de la
Universidad de Zaragoza, Zaragoza, Spain.
The material described in this paper consists of: nine
vertebral centra identified as cervical (MPZ 2013/398, MPZ
2013/402, MPZ 2013/400, MPZ 2013/406), pectoral (MPZ
2013/401), dorsal (MPZ 2013/403), sacral (MPZ 2013/405)
and caudal (MPZ 2013/399 and MPZ 2013/396), and two
teeth (MPZ 2013/407 and MPZ 2013/404). We have clas-
sified the vertebrae as cervical, pectoral, dorsal, sacral and
caudal following the work of seeley (1877). The systematic
terminology used in the comparison and discussion follows
Benson & druckenmiller (2014).
4. Systematic palaeontology
Superorder Sauropterygia owen, 1860
Order Plesiosauria de Blainville, 1835
Plesiosauria indet.
Figs. 2-4
Cervical vertebrae (Fig. 2A-D). Cervical vertebra bear un-
divided rib facets located wholly on the centrum. We can
distinguish two different morphologies of cervical centra.
The first kind includes MPZ 2013/400 and MPZ 2013/406
(Fig. 2A-B). These centra have the rib facets located on
the ventrolateral surface. They are “crater-like”, with rai-
sed rims (as observed in e.g., Alzadasaurus, welles 1962;
Rhomaleosaurus smith & Benson 2014). The outline of the
rib facets is concave ventrally and subtriangular dorsally.
The margins of the articular faces are well-ossified and de-
fined (as in Muraenosaurus, a
ndrews
1910). MPZ 2013/400
(Fig. 2A) is a small and well-preserved vertebral centrum
(although the neural arch and spine have been broken off).
The rib facets are anteroposteriorly long, occupying most
of the anteroposterior length of the centrum. It has slightly
concave oval articular faces (i.e. amphicoelous centra) with
a shallow notochordal pit, as in other plesiosaurians (e.g.,
Leptocleidus superstes, kear & Barret 2011; Gronausaurus
wegneri, hampe 2013). The centrum is wider than high and
approximately as long as high (35 mm wide, 30 mm high and
28 mm long). The base of the neural canal is concave and it
is expressed on the articular faces as a small dorsomedian
concavity. There is a pair of foramina on the dorsal surfa-
ce, located at mid-length immediately medial to the neural
arch facets, a character shared among plesiosaurians (Ben-
son & druckenmiller 2014). The lateral surface above the
singular rib facets is slightly concave and it lacks the lateral
keel common in long-necked plesiosaurians (welles 1962).
The neural arch is not totally fused to the centrum, and the
neurocentral suture is clearly visible. The ventral surface is
concave anteroposteriorly. On the ventral surface there is a
midline ridge (i.e. a ventral keel) separating a pair of closely
set nutritive foramina, as in several specimens of rhomaleo-
saurids (e.g., Meyerasaurus victor, smith & vincent 2 010),
pliosaurids (e.g., Pliosaurus brachydeirus, owen 1842) and
plesiosauroids (e.g., Edgarosaurus muddy, druckenm iller
2002; Muraenosaurus, andrews 1910). The median ventral
ridge in MPZ 2013/400 is very weak and the foramina are
very close together. The anterior and posterior borders of the
centrum are raised into fine rugosities, as in Muraenosau-
rus (andrews 1910), Pantosaurus (o’keefe & wahl 2003)
and Cryonectes (vincent et al. 2013a). MPZ 2013/406 (Fig.
2B) is a ventrolateral fragment of a vertebral centrum. On
the ventral surface there is a sharp longitudinal ridge that
separates the nutritive foramina, which are located in a de-
pressed area.
The second morphology is shared by MPZ 2013/398 and
MPZ 2013/402 (Fig. 2C-D). These vertebrae have slightly
eschweizerbart_xxx

On the presence of plesiosaurs in the Blesa Formation (Barremian) in Teruel (Spain) 217
concave articular faces (i.e. amphicoelous centra), oval in
outline (wider than high), and surrounded by a border, poorly
preserved due to erosion. These centra are shorter anteropo-
steriorly than high dorsoventrally. The width of the articular
faces is at least 1.2 times the height, and the height is appro-
ximately 1.3 times the length (W>H>L). The ventral surface
Fig. 2. Plesiosaurian remains from the Blesa Formation. A-D, cervical vertebrae: A, MPZ 2013/400 in articular (1), lateral
(2) and ventral view (3); B, MPZ 2013/406 in articular (1), lateral (2) and ventral view (3); C, MPZ 2013/398 in articular (1),
lateral (2) and ventral view (3); D, MPZ 2013/402 in articular (1) and ventral view (2). E, pectoral vertebra, MPZ 2013/401
in articular (1) and lateral view (2). F, dorsal vertebra, MPZ 2013/403 in lateral view. G, sacral vertebra, MPZ 2013/405 in
articular (1) and lateral view (2). H-I, caudal vertebrae: H, MPZ 2013/396 in posterior (1) and right lateral view (2); I, MPZ
2013/399 in posterior (1), right lateral (2) and ventral view (3). Scale bar 5 cm.
eschweizerbart_xxx

218 J. Parrilla-Bel and J.I. Canudo
is rounded, convex mediolaterally, and bears at least one pair
of nutritive foramina (foramina subcentralia). These forami-
na are located ventrolaterally (i.e. not close together). The
centra lack a ventral keel separating the foramina. They have
prominent facets for the ribs, located on the lateral surface,
around mid-height of the vertebral centra. The rib facets are
undivided, and subcircular in outline. They are large, but
do not reach the rim of the articular faces. The vertebral
centra also lack a lateral keel. MPZ 2013/398 (Fig. 2C) is
55 mm wide, 46 mm high and 35 mm long. On the rounded
ventral surface there are two pairs of foramina. On the dorsal
surface of the centrum there is another nutritive foramen,
immediately medial to the neural arch facets. MPZ 2013/402
(Fig. 2D) is a small, eroded centrum. It is approximately 35
mm wide, 25 mm high and 20 mm long.
Pectoral vertebra. The pectoral vertebrae are transitional
between cervical and dorsal vertebrae (sensu seeley 1874).
MPZ 2013/401 (Fig. 2E) is broken, and only half of the cen-
trum is preserved. The vertebral centrum is higher than long,
with a length of 35 mm. The articular faces are concave. It
has an oval rib facet with the long axis vertically oriented.
The rib facet is located dorsolaterally on the centrum, in
contact with the neural arch, which is broken. The ventral
surface is rounded, convex mediolaterally, and has a pair
of ventrolateral nutritive foramina. A ventral keel has been
described for some plesiosaurians, such as Gronausaurus
wegneri (h
ampe
2013) and Raptocleidus (e
vans
2012), i n
contrast to MPZ 2013/401, which lacks a longitudinal weakly
developed vent ra l keel.
Dorsal vertebra. MPZ 2013/403 (Fig. 2F) is a poorly pre-
served centrum. It lacks rib facets, which would be located
on the neural arch. There is a pair of foramina on the ventral
surface rather than on the lateral surface. The ventral surface
is concave anteroposteriorly, and rounded mediolaterally.
Sacral vertebra. MPZ 2013/405 (Fig. 2G) is broken, and
only half of the centrum is preserved. It is 35 mm long and
39 mm high. The articular faces are concave; one of them
has a small convexity in the center. The articular rib facet
is subcircular and enlarged, occupying most of the lateral
surface, and it joins the neural arch dorsally.
Caudal vertebrae. The caudal vertebrae have rib facets
located laterally on the vertebral centrum and facets for the
haemal arches on the ventral surface. The vertebrae found in
the Blesa Formation have two different morphologies. MPZ
2013/399 (Fig. 2I) is a markedly amphicoelous centrum, with
roughly octagonal articular faces bordered by the base of the
neural canal, the flat ventral surface and the chevron facets.
Some plesiosaurians such as Gronausaurus have articular
faces for the caudal vertebral centra that are very slightly
concave or nearly flat (hampe 2013). The vertebral centrum
of MPZ 2013/399 is wider than high and higher than long
(37, 32 and 24 mm respectively). The rib facets are promi-
nent, oval and “crater-like”, located around mid-height of the
vertebral centrum. The ventral surface is flat. There are two
longitudinal ventrolateral ridges and a median foramen bet-
ween the ridges, observed also in some other plesiosaurians
from Europe (e.g., Hastanectes, Leptocleidus superstes B
en
-
son & druckenmiller, 2014; Colymbosaurus andreassen,
2004, or the northern Argentinian Patagonia elasmosaurid,
Gasparini & salGado 2000). There are also on this surface
some small pits, but they don’t seem to be real foramina. The
posterior facets for the haemal arches are very developed and
they truncate the ventrolateral ridges obliquely. The lateral
surface between the rib facet and the chevron facet is deeply
concave. MPZ 2013/396 is broken, and only the right half of
the centrum and the base of the neural arch are preserved
(Fig. 2H). The articular faces are concave, and a sharply
defined border surrounds them. The vertebral centrum is
higher than long (40 mm long and approximately 45 mm
Fig. 4. A, MPZ 2013/404 in lingual view. B, MPZ 2013/407.
Scale bar 2 cm.
Fig. 3. MPZ 2013/906 in posteroventrolateral view. Scale
bar 3 cm. Abbreviations: cf, chevron facet; fo, foramen; vlr,
ventrolateral ridge; rf, rib facet.
eschweizerbart_xxx

On the presence of plesiosaurs in the Blesa Formation (Barremian) in Teruel (Spain) 219
high). It has an enlarged subcircular rib facet, located late-
rally on the centrum. The facet for the chevron is on the po-
steroventral surface, located laterally (Fig. 3). MPZ 2013/396
has a small ventrolateral ridge (partially broken) that goes
longitudinally from the chevron facet to the mid-length of
the centrum. There is a ventrolateral foramen between the rib
facet and the chevron facet, and a ventral foramen, medially
to the chevron facet (Fig. 3) also described for example in
an Early Cretaceous elasmosaurid from Neuquén Basin in
Argentina (lazo & cichowolski 20 03).
Teeth (MPZ 2013/404 and MPZ 2013/407) (Fig. 4). Both
teeth are slender and weakly curved. The cross-section is
oval, slightly labiolingually compressed. The apices taper
to a rounded point and show no evidence of faceting by
wear. These characters are shared in many plesiosaurians
(ketchum 2011), such as for example Eromangasaurus ca-
rinognathus (kear 2005) and Leptocleidus superstes (kear
& B
arret
2011), but differ from both pliosaurids and rho-
maleosaurids, which have robust teeth with large roots and
wear (kea r & Barret 2011). MPZ 2013/407 (Fig. 4B) is 52
mm long. The crown is 30 mm long, and part of the root is
broken off. It is ornamented with fine apicobasally oriented
ridges. The ornamentation is on the whole crown, but it is
more conspicuous on the lingual face. MPZ 2013/404 (Fig.
4A) is a small tooth, and only the crown has been preserved
(the crown-root limit is marked by a color change, loss of
ornamentation, and the beginning of the pulp cavity). It is
12 mm long, with a maximum diameter of 5 mm at the base
of the crown, and ornamented by fine apicobasally oriented
ridges on the lingual surface.
5. Discussion
The Blesa Formation has yielded numerous continental
vertebrate fossils although marine reptiles are scarce
and fragmentary restricted to the basal part of Calizas
de Morenillo member. The vertebrae described have
nutritive foramina on the ventral surface of the cen-
tra, a plesiosaurian character (k
etchum
2011; s
torrs
1991). Paired lateral subcentral foramina is a pisto-
saurian synapomorphy, which includes plesiosaurians
and the closer ancestors (s
ander
et al. 1997; r
ieppel
et al. 2002). Considering the general morphology and
the age and geological context we assign the vertebral
remains to Plesiosauria. Also the morphology and or-
namentation of the teeth allow us to relate them with
plesiosaurians (Brown 1981). They may be assigned
to the “piercing guild” described by massare (1987).
For now it is difficult to discern whether the plesiosaur
fossils include a single taxon or more.
5.1. Ontogeny
As occurs in other reptile groups, the joint of the neu-
ral arches and ribs to the vertebral centra may be an
ontogenetic character (Brown 1981). This may reflect
osteological maturity (an adult or subadult specimen)
for MPZ 2013/396, MPZ2013/399, MPZ 2013/401 and
MPZ 2013/405. MPZ 2013/400 is a small centrum with
the neural arch not totally fused to the centrum and the
neurocentral suture clearly visible, and MPZ 2013/398
lacks the neural arch, suggesting that it was not fused
with the vertebral centra. MPZ 2013/400 and 398 re-
present immature individuals.
5.2. Early Cretaceous plesiosaurians
B
ardet
et al. (2014) mapped the distribution of marine
reptiles onto Mesozoic palaeogeographical maps at se-
lected key periods. Many of the late Early Cretaceous
plesiosaurians come from the Aptian and Albian out
-
crops of Australia, but also from the Aptian of Colom-
bia and the Albian of Canada and the United States of
America. On the other hand, most “early” Early Creta-
ceous plesiosaurians come from Europe: the Berriasian
of Germany and the Valanginian and Barremian of the
United Kingdom, as well as from the Hauterivian of
Russia, the Hauterivian-Barremian of Australia, and
the Valanginian of South Africa (Table 1).
As pointed out by B
enson
& d
ruckenmiller
(2014),
there was a substantial turnover of marine reptiles over
an extended interval at the Jurassic-Cretaceous boun-
dary, and Cretaceous plesiosaurians are only repre-
sented by three lineages: Xenopsaria, Cryptoclididae
(Plesiosauroidea) and Brachaucheninae (Pliosauridae)
(Fig. 5). Pliosaurids are only represented in the Early
Cretaceous by Kronosaurus, and Cretaceous cryptocli-
dids are also very rare, only represented by the Russi-
an taxon Abyssosaurus nataliae. The clade Xenopsaria
comprises the clades Elasmosauridae and Leptocleidia.
Within Xenopsaria, the better-represented lineage, wi-
dely distributed in the Early Cretaceous, is Leptoclei-
dia. Elasmosauridae has some Early Cretaceous taxa,
and reached great diversity in the Late Cretaceous.
Most plesiosaur genera appear to have been rather
endemic, their known occurrences being restricted to
a few basins. In the Lower Cretaceous, only the genus
Leptocleidus had a cross-oceanic distribution (Bardet
et al. 2014).
5.3. Comparative anatomy
Many species of plesiosaurians are based on a few
vertebrae, or even a single vertebra (welles 1962).
However, there is a high degree of variability in the
vertebral centra due to ontogenetic allometry, intraco-
eschweizerbart_xxx

220 J. Parrilla-Bel and J.I. Canudo
lumn variation and taxonomic variation, which is very
relevant for assigning centra to different taxa (a
ndrews
1910; B
rown
1981; B
ardet
et al. 2003; o’k
eefe
& h
il
-
ler 2006; knutsen 2012; Benson et al. 2011; sachs &
k
ear
2014). some plesiosaur taxa have tremendously
elongate necks composed of a great number of indivi-
dual vertebrae, which can create a problem in scoring
cervical characters that are variable within the series
as a whole (druckenmiller & russell 2008a). The
location of the vertebral centrum in the column must
be known to make a taxonomically meaningful com-
parison.
The proportions of the cervical centra have com-
monly been related with the length of the neck (e.g.,
ketchum & Benson 2010; Brown 1981). All the cer-
vical centra described herein are to a greater or les-
ser extent wider than high (W>H), a feature present
in many plesiosaurians (B
rown
1981). Proportionally
elongated vertebrae (L>H, typical of the anterior cer-
vical centra in adults) is a character of “long-necked
Fig. 5. Stratigraphically calibrated consensus cladogram (modified from Benson & druckenmiller 2 014).
eschweizerbart_xxx

On the presence of plesiosaurs in the Blesa Formation (Barremian) in Teruel (Spain) 221
plesiosaurs” (i.e. plesiosauromorphs) (e.g., Gasparini
& s
alGado
2000; B
rown
1981, 1993). Elasmosaurids
from the Lower Cretaceous, such as Eromangasaurus
carinognathus (k
ear
20 05), Callawayasaurus colom-
biensis (welles 1962) or the Speeton Clay plesiosau-
rian (B
enson
& d
ruckenmiller
2014), have cervical
centra that are substantially longer than high. All the
cervical centra collected in the Blesa Formation are
shorter than high (H>L) or are of subequal height and
length, but in no case does the length exceed the height.
MPZ 2013/398 and MPZ 2013/402 are substantially
shorter than high. Short cervical centra is a character
of Pliosauroidea (sensu Brown 1981). andrews (1913)
and k
etchum
(2007) stated that pliosaurids cervical
centra are approximately half as long as they are high
or wide. According to these authors, MPZ 2013/398 and
402 could have a pliosauroid non pliosaurid proportions
(vincent 2011). By contrast, MPZ 2013/400 is appro-
ximately as long as high, a character shared among
leptocleidids such as Umoonasaurus demoscyllus,
Nichollssaura borealis, Leptocleidus capensis, Lepto-
cleidus clemai, Hastanectes valdensis, Vectocleidus
pastorum (slightly shorter) Plesiopleurodonor Bran-
casaurus brancai (slightly longer), and also present in
the cryptoclidid Abyssosaurus nataliae (cruickshank
& l
onG
1997; B
enson
& d
ruckenmiller
2014) (Fig. 5).
However, comparisons of their dimensions with those
of other plesiosaurians are not diagnostic, because the
centrum proportions vary according to ontogeny and
the position in the vertebral column (Brown 1981).
The anterior cervical vertebrae of many derived
elasmosaurids have binocular-shaped articular surfa-
ces, with a ventral medial notch, and the lateral sides
of the vertebral centra are concave with a prominent
longitudinal ridge (Brown 1993; sachs & kear 2014),
but these characters are not found in all taxa. Some
Late Cretaceous elasmosaurids lack the lateral ridge
on the cervical centra (e.g., Futabasaurus and Mo-
roccan specimens of elasmosaurids, sato et al. 2006;
v
incent
et al. 2013a), and in the basal elasmosaurids
(e.g., Callawayasaurus, welles 1962; druckenmiller
& r
ussell
2008a; B
enson
& d
ruckenmiller
2014) and
some Maastrichtian specimens the ventral notch is ab-
sent (vincent et al. 2013b). Both characters are absent
in the Blesa Formation cervical vertebrae. However, an
additional problem in classifying the material is that
the lateral longitudinal ridge may also vary along the
series, being lost on posterior cervical vertebrae (e.g.,
druckenmiller & russell 2008a). The articular faces
of MPZ 2013/398 and MPZ 2013/402 are oval (i.e. not
binocular-shaped). In MPZ 2013/400 the articular faces
are also oval, but slightly “trapezoidal”, wider than long
and as long as high, as in the anterior cervical vertebrae
of the Cretaceous cryptoclidid Abyssossaurus nataliae
(Berezin 2011) (Fig. 5).
All the cervical vertebrae from the Blesa Formation
have undivided rib facets. Undivided cervical rib facets
are a character convergent among derived Cretaceous
plesiosaurians (carpenter 1996; o’keefe 2001). MPZ
2013/398 and MPZ 2013/402 have cervical rib facets
located around mid-height of the centrum. This is a
synapomorphy of the pliosaurid clade Brachaucheninae
(B
enson
& d
ruckenmiller
2014), however the position
of the rib facets varies in many taxa, including the rib
facets at mid-centrum the posterior-most cervicals of
almost all plesiosaurians, as they migrate onto the neu-
ral arch in the pectoral series. They also resemble the
posterior cervical vertebrae of Abyssosaurus (Berezin
2011) (Fig. 6).
MPZ 2013/406 has a marked ventral keel, and MPZ
2013/400 a weak rounded median keel. By contrast,
MPZ 2013/398 and MPZ 2013/402 have a convex ven-
tral surface. The ventral keel in cervical vertebrae has
been described in several taxa, but this character also
varies throughout the vertebral series (tarlo 1960;
druckenmiller & russell 2008a; vincent 2011). Wi-
thin Lower Cretaceous plesiosaurians, the presence of
a sharp ventral keel dividing the ventral surface into
two depressions is found in Edgarosaurus and Plesio-
pleurodon (Benson & druckenmiller 2014). A roun-
ded keel has been described in Leptocleidus superstes
and Leptocleidus clemai for the mid-posterior cervical
vertebrae (kear & Barret 2 011; kear 2005) (Fig. 6),
and a sharper and more blade-like keel in L. capensis
and Nichollssaura borealis (d
ruckenmiller
& r
ussell
2008b). The cervical centra of Gronausaurus exhibit a
longitudinal ridge dividing a pair of nutritive foramina,
and the ventral ridge becomes weaker and weaker until
it nearly disappears at the posteriormost preserved cen-
trum (h
ampe
2013), and the same occurs in other plesi-
osaurians (druckenmiller & russell 2008a; vincent
2011). Hastanectes valdensis has a transversely narrow
ventral midline ridge on the cervical centra (Benson et
al. 2012). For Callawayasaurus (w
elles
1962; c
ar
-
penter 1999) the ventral keel is smoothly rounded and
poorly developed on the anterior cervicals and changes
first to sharper and then to broader posteriorly on the
column. B
erezin
(2011) describes a medial eminence
between two longitudinal fossae with large foramina on
the ventral surface of Abyssosaurus cervical vertebrae.
Brown (1981) stated that the presence or absence of
a ventral keel could vary ontogenetically, while other
eschweizerbart_xxx

222 J. Parrilla-Bel and J.I. Canudo
Fig. 6. Comparative plate of plesiosaurian vertebrae. Scale bar 5 cm. A, cervical vertebra MPZ 2013/398 in articular (1),
lateral (2) and ventral view (3). B, cervical vertebra MPZ 2013/400 in articular (1), lateral (2) and ventral view (3). C, cer-
vical vertebra of Pantosaurus striatus, YPM 543 (redrawn from O’keefe & wahl 2003) in articular (1), lateral (2) and
ventral view (3). D, cervical vertebrae of Leptocleidus clemai WAM 92.8.1-29 (redrawn from cruickshank & lonG 1997)
in anterior (1), lateral (2) and ventral view (3). E, cervical vertebrae of elasmosaurid (redrawn from sachs & kear 2015 ),
eschweizerbart_xxx

On the presence of plesiosaurs in the Blesa Formation (Barremian) in Teruel (Spain) 223
authors have considered it not to be an ontogenetic cha-
racter (e.g., Thalassiodracon, vincent et al. 2013a).
Cervical vertebrae are the most informative verte-
brae in the vertebral column. MPZ 2013/398 and MPZ
2013/402 are short centra, with the facets for the ribs
at mid-height of the centrum and the ventral surface
lacking a midline keel. These features are shared with
Kronosaurus queenslandicus (Brachaucheninae, Plio-
sauridae) and also with the posterior cervical vertebrae
of Abyssosaurus (Fig. 6). However, the cervical centra
of Kronosaurus are higher dorsoventrally than wide
mediolaterally (r
omer
& l
ewis
1959), and they are gre-
atly enlarged compared to the vertebrae described here.
On the other hand, MPZ 2013/400 shares some fea-
tures with the Jurassic cryptoclidids Pantosaurus and
Muraenosaurus (o’keefe & wahl 2003): well-ossified
articular faces, the size and proportions of the centra,
the position and shape of the rib facets or the ornamen-
tation (fine rugosities on the borders of the centrum)
(Fig. 6), but Blesa Formation material is not stratigra-
phically consistent with these taxa. This morphology is
also very similar to the Pliensbachian pliosaurid Cry-
onectes neustriacus (vincent et al. 2013a, figs. 8-10),
or to the Early Cretaceous cryptoclidid Abyssosaurus
nataliae. However, it also shares characters with lepto-
cleidids, as well as some with polycotylids and elasmo-
saurids (Cryptoclidia).
van Beneden (1882) pointed out that the distance
between the subcentral foramina is a useful character
for determining the position of a particular centrum
in the column; the foramina are closer together on the
anterior vertebrae, while on the posterior ones they are
further apart. The small distance between the subcen-
tral foramina of MPZ 2013/400 and MPZ 2013/406
could indicate that these vertebrae are in a more anteri-
or position in the column than MPZ 2013/398 and MPZ
2013/402. However, the isolated material collected is
too fragmentary to discern whether the differences ob-
served are due to the position of each vertebra in the
vertebral column, to a different taxonomic assignation,
or even a combination of both possibilities.
The dorsal centra in plesiosaurians may bear more
than one pair of foramina, and at least one pair will
usually visible in lateral view (ketchum 2011), as it
occurs for example in Vectocleidus pastorum (Benson
et al. 2012), with two lateral foramina on their lateral
surfaces, or Thililua longicollis (B
ardet
et al. 2003),
with highly located nutritive foramina on the lateral
surface). MPZ 2013/403 has a pair of nutritive forami-
na on the ventral surface. Styxosaurus has also ventral
nutritive foramina in the middle of the centrum, but
they are separated by a broad, shallow anteroposteri-
orly running ridge (sachs 2004). MPZ 2013/403 lacks
a ventral ridge.
The caudal vertebra MPZ 2013/399 is wider than
high. This character is present in Jurassic taxa (e.g.,
Plesiosaurus dolichodeirus, vincent & taquet 2010)
and also shared with the anterior caudal centra of some
Lower Cretaceous plesiosaurians such as Brancasaurus
or Leptocleidus superstes (kear & Barret 2011; Ben-
son
& d
ruckenmiller
2014). Both the caudal centra de-
scribed here have their rib facets located at mid-height
of the centrum. This also occurs in Abyssosaurus, some
basal elasmosaurids and Kronosaurus (B
enson
& d
ru
-
ckenmiller 2014). The presence of only a single, me-
dian subcentral foramen on the ventral surface of each
caudal vertebra (MPZ 2013/399) is a character present
in some xenopsarians such as Hastanectes, Leptocle-
idus superstes or the Speeton Clay plesiosaurian (see
Benson & druckenmiller 2014 for discussion). Both
the Blesa Formation caudal vertebrae have the facets
for the haemal arches mainly on the posterior edge, as
in Brancasaurus brancai, the Speeton Clay plesiosau-
rian and GWWU A3.B2 (B
enson
& d
ruckenmiller
2014). Umoonasaurus, Leptocleidus superstes, Ha-
stanectes valdensis and Kronosaurus have the che-
vron facet located equally on the anterior and posterior
edges of the centrum. However, this character can also
vary along the caudal row, e.g. in the caudals anterior
to number 17 there are only two chevron facets situated
on the posterior end of the centrum in Colymbosau-
rus, and there are four facets in the rest of the caudals
Aristonectes parvidens in articular view (1) and Libonectes morgani in lateral view (2) (scale unknown). F, cervical verte-
brae (C24–C26) of Abyssosaurus nataliae MChEIO, no. PM/1 (redrawn from Berezin 2011) in articular (1), lateral (2) and
ventral view (3). G, posterior cervical vertebrae (E1 and E2 are the 51 and E3 is the 37) of Abyssosaurus nataliae MCh E IO,
no. PM/1 (redrawn from Berezin 2011) in articular (1), lateral (2) and ventral view (3). H, cervical vertebra of Pliosaurus
brachyspondylus, CAMSM J.29564 (redrawn from knutsen 2012) in articular (1), lateral (2) and ventral view (3). I, caudal
vertebra of Colymbosaurus svalbardensis; I1-2, 13 caudal vertebra (PMO A 27745) (redrawn from a
ndreassen
2004) in
anterior (1) and lateral view (2); I3, caudal vertebra PMO 216.838 (redrawn from knutsen et al. 2012: figs. 4 A, D) in ventral
view. Abbreviations: cf, chevron facet; fo, foramen; lk, lateral keel; nc, neural canal; np, notochordal pit; ns, neurocentral
suture; vn, ventral notch; vr, ventral ridge; r, rib; rf, rib facet.
eschweizerbart_xxx

224 J. Parrilla-Bel and J.I. Canudo
(andreassen 2004) (Fig. 6).
Neural spines and zygapophyses can bear some im-
portant characters (druckenmiller & russell 2008a;
Benson & druckenmiller 2014), but unfortunately no
neural arch or neural spine has been preserved and the
centra exhibit few diagnostic characters among plesio-
saurians, making comparisons with other taxa difficult.
The teeth lack carinae, like Leptocleidus superstes
(but unlike Leptocleidus capensis, which has mesio-
distal carinae, c
ruickshank
1997). MPZ 2013/404 is
a very small tooth compared with MPZ 2013/407, in-
deed smaller than most plesiosaurian teeth. However,
some Lower Cretaceous taxa, such as Callawayasaurus
(welles 1962), Brancasaurus and Leptocleidus capen-
sis (Benson et al. 2012; cruickshank 1997), have two
tiny central premaxillary teeth between the large lo
-
wer teeth at the front of each dentary, followed by the
large premaxillary and maxillary teeth. This is also
the case an Early Jurassic plesiosauroids (Brown et al.
2013). Moreover, Cretaceous taxa such as Kaiwhekea
have only small teeth (cruickshank & fordyce 2 0 02).
Tooth size also varies within the maxillary dentition
of each specimen, as the teeth become progressively
smaller caudally (druckenmiller & russell 2008a).
6. Conclusions
The size of the vertebrae, the proportions of height,
length and width, the concavity and shape of the arti-
cular faces, the position of the rib facets and nutritive
foramina are, among others, characters that may vary
along the vertebral column or during ontogeny in many
plesiosaurian taxa. This variability and the scarce dia-
gnostic characters in the vertebral centra, together with
the limited availability of Early Cretaceous specimens
for comparison make it difficult to identify the materi-
al from the Blesa Formation. We therefore assign this
material to Plesiosauria indet. These are the first plesio-
saurian fossils described from the Barremian of the Ibe-
rian Peninsula, a period of time where plesiosaurs are
scarcely represented worldwide: the Early Cretaceous
plesiosaurian specimens are Brancasaurus, Hastanectes
and Vectocleidus from Europe; Abyssosaurus from Rus-
sia; Eromangasaurus, Kronosaurus and Umoonasau-
rus from Australia; Wapuskanectes, Nichollsia and
Edgarosaurus from North America; Callawayasaurus
and Brachachenius from South America and Leptoclei-
dus from Europe, Australia and South Africa); and the
only known Barremian representatives are Vectocleidus,
Leptocleidus and Brachauchenius.
Moreover, these isolated finds, though fragmentary
and undiagnostic, suggest an unrecognized palaeogeo
-
graphical distribution in Early Cretaceous plesiosaurs.
A detailed study of this formation and the acquisition
of new material would be of great interest to document
a poorly known episode in the history of plesiosau-
rians and improve our understanding of plesiosaurian
evolution.
Acknowledgements
This paper is subsidized by the Spanish Ministerio de Eco-
nomía y Competitividad, the European Regional Develop-
ment Fund (CGL2014-53548-P), and the Government of
Aragón (“Grupos Consolidados” and “Dirección General
de Patrimonio Cultural”). JPB is supported by a predoctoral
research grant (B105/10) from the Government of Aragón.
We thank Jesús sender palomar, fernando Gracia and
José mar ía aBad, who provided some of the material de-
scribed. We thank r
upert
G
lasGow
, who revised the English
grammar. We would also like to thank B.A. schumacher
and P. v
incent
, whose comments improved the quality of
this paper.
References
a
ndreassen
, B.h. (2004): Plesiosaurs from Svalbard. Un-
published Master Thesis. – 109 pp.; Oslo (University of
Oslo).
andrews, C.W. (1910): A descriptive catalogue of the marine
reptiles of the Oxford Clay, Part I. – XXIII + 205 pp.;
London (British Museum, Natural History).
a
ndrews
, C.W. (1913): A descriptive catalogue of the Marine
Reptiles of the Oxford Clay, Part II. – 205 pp.; British
Museum (Natural History), London.
a
ndrews
, C.W. (1922): Description of a new plesiosaur from
the Weald Clay of Berwick (Sussex). – Quarterly Journal
of the Geological Society of London, 78: 285-298.
aurell, M., Bádenas, B., canudo, J.I. & ruiz-omeñaca,
J.I. (2004): Evolución tectosedimentaria de la Fm. Blesa
(Cretácico Inferior) en el entorno del yacimiento de ver-
tebrados de La Cantalera (Josa, Teruel). – Geogaceta,
35: 11-13.
Bakker, R.T. (1993): Plesiosaur extinction cycles- Events
that mark the beginning, middle and end of the Cretace-
ous. – In: caldwell, w.G.e. & kaufman, e.G. (E ds.):
Evolution of the Western Interior Basin. – Geological
Association of Canada, Special Paper, 39: 641-664.
B
ardet
, N., f
alconnet
, J., f
ischer
, V., h
oussayec
, A., J
ouve
,
S., pereda suBerBiola, X., pérez-García, A., raGe, J.C.
& v
incent
, P. (2014): Mesozoic marine reptile palaeo-
biogeography in response to drifting plates. – Gondwa-
na Research, 26 (3): 869-887. http://dx.doi.org/10.1016/j.
gr.2014.05.005
Bardet, N., pereda suBerBiola, X. & Jalil, N.E. (2003):
A new polycotylid plesiosaur from the Late Cretaceous
eschweizerbart_xxx

On the presence of plesiosaurs in the Blesa Formation (Barremian) in Teruel (Spain) 225
(Turonian) of Morocco. – Comptes rendus Palevol, 2:
307-315.
Bardet, N., pereda suBerBiola, X. & ruiz-omeñaca, J. I.
(2008): Mesozoic marine reptiles from the Iberian Penin-
sula. – Geo-Temas, 10: 12 45-1248.
Benson, R.B. & druckenmiller, P.S. (2014): Faunal turno-
ver of marine tetrapods during the Jurassic-Cretaceous
transition. – Biological Reviews, 89 (1): 1-23.
Benson, R.B., Butler, R.J., lindGren, J. & smith, A. S.
(2010): Mesozoic marine tetrapod diversity: mass extinc-
tions and temporal heterogeneity in geological megabi-
ases affecting vertebrates. – Proceedings of the Royal
Society, (B), 277: 829-834.
Benson, R.B., ketchum, H.F., naish, D. & turner, L.E.
(2013): A new leptocleidid (Sauropterygia, Plesiosauria)
from the Vectis Formation (early Barremian-early Ap-
tian; Early Cretaceous) of the Isle of Wight and the evo-
lution of Leptocleididae, a controversial clade. – Journal
of Systematic Palaeontology, 11 (2): 233-250. doi:10.108
0/14772019.2011.634444
Benson, r.B., ketchum, h.f., noe, l.f. & Gómez-pérez, m.
(2011): New information on Hauffiosaurus (Reptilia, Ple-
siosauria) based on a new species from the Alum Shale
Member (lower Toarcian: Lower Jurassic) of Yorkshire,
UK. – Palaeontology, 54 (3): 547-571.
Berezin, A.Y. (2011): A new plesiosaur of the family ari-
stonectidae from the early cretaceous of the center of
the Russian platform. – Paleontological Journal, 45 (6):
648-660.
B
lainville
, H.D.
de
(1835): Description de quelques espèces
de reptiles de la Californie, precede de l’analyse d’un
système general d’Erpetologie et d’Amphibiologie. –
Nouvelles Annales du Museum National d’Histoire Na-
turelle, Paris, 4: 233-296.
Brown, D.S. (1981): The English Upper Jurassic Plesiosau-
roidea (Reptilia) and a review of the phylogeny and clas-
sification of the Plesiosauria. – Bulletin of the British
Museum (Natural History), Geology Series, 35: 253 -347.
B
rown
, D.S. (1993): A taxonomic reappraisal of the families
Elasmosauridae and Cryptoclididae (Reptilia: Plesiosau
-
roidea). – Revue de Paléobiologie, 7: 9-16.
Brown, d., vincent, p. & Bardet, N. (2013): Osteological
redescription of the skull of Microcleidus homalospon-
dylus (Sauropterygia, Plesiosauria) from the Lower
Jurassic of England. – Journal of Paleontology 87 (4):
537-5 49.
canudo, J.I., Gasca, J.M., aurell, M., Badiola, A., Blain,
H.-A., cruzado-caBallero, P., Gómez-fernández, D.,
moreno-azanza, M., parrilla, J., raBal-Garcés, R. &
ruiz-omeñaca, J.I. (2010): La Cantalera: an exceptional
window onto the vertebrate biodiversity of the Haute-
rivian-Barremian transition in the Iberian Peninsula. –
Journal of Iberian Geology, 36 (2): 29-324.
c
anudo
, J.I., G
asulla
, J.M., G
ómez
-f
ernández
, D., o
rteGa
,
F., sanz, J.L. & yaGüe, P. (2008): Primera evidencia de
dientes aislados atribuidos a Spinosauridae (Theropoda)
en el Aptiano inferior (Cretácico Inferior) de Europa:
Formación Arcillas de Morella (España). – Ameghini-
ana, 45 (4): 6 49 - 652.
carpenter, K. (1996): A review of short-necked plesiosaurs
from the Cretaceous of the Western Interior, North Ame-
rica. – Neues Jahrbuch für Geologie und Paläontologie,
Abhandlungen, 201: 2 5 9 -2 8 7.
carpent er, K. (1999): Revision of North American elas-
mosaurs from the Cretaceous of the Western Interior.
– Paludicola, 2 (2):148-173.
c
ruickshank
, A.R.I. (1997): A Lower Cretaceous pliosau-
roid from South Africa. – Annals of the South African
Museum, 105: 2 07-226.
cruickshank, a.r. & fordyce, r.e. (2002): A new marine
reptile (Sauropterygia) from New Zealand: further evi-
dence for a Late Cretaceous austral radiation of crypto-
clidid plesiosaurs. – Palaeontology, 45 (3): 557-575.
cruickshank, A.R.I. & lonG, J.A. (1997): A new species of
pliosaurid reptile from the Early Cretaceous Birdrong
Sandstone of Western Australia. – Records of the We-
stern Australian Museum, 18: 263-276.
druckenmiller, P.S. (2002): Osteology of a new plesiosaur
from the Lower Cretaceous (Albian) Thermopolis Shale
of Montana. – Journal of Vertebrate Paleontology, 22
(1): 29- 42 .
d
ruckenmiller
, P.S. & r
ussell
, A.P. (2006): A new elas-
mosaurid plesiosaur (Reptilia: Sauropterygia) from the
Lower Cretaceous Clearwater Formation, northeastern
Alberta, Canada. – Paludicola, 5 (4): 184-199.
druckenmiller, P.S. & russell, A.P. (2008a): A phylogeny
of Plesiosauria (Sauropterygia) and its bearing on the
systematic status of Leptocleidus andrews , 1922. –
Zootaxa, 1863: 1-12 0.
druckenmiller, P.S. & russell, A.P. (2008b): Skeletal ana-
tomy of an exceptionally complete specimen of a new
genus of plesiosaur from the Early Cretaceous (early
Albian) of northeastern Alberta, Canada. – Palaeonto-
gr aphic a, (A), 283: 1-33.
evans, M. (2012): A new genus of plesiosaur (Reptilia: Sau-
ropterygia) from the Pliensbachian (Early Jurassic) of
England, and a phylogeny of the Plesiosauria (Doctoral
dissertation, University of Leicester). – 397 pp.; Leicester
(University of Leicester).
Gasparini, Z. & salGado, L. (2000): Elasmosáuridos (Pie-
siosauria) del Cretácico Tardío del norte de Patagonia.
– Revista Española de Paleontología, 15 (1): 13-21.
Gaspa rini, z., salGado, l. & casado, S. (20 03a): Maa strich-
tian plesiosaurs from northern Patagonia. – Cretaceous
Research, 24: 157-170.
Gasparini, Z., salGado, L. & parr as, A. (2007): Late creta-
ceous plesiosaurs from northern Patagonia, Argentina.
– Geological Journal, 42 (2): 185-202.
hampe, O. (1992): Ein großwüchsiger Pliosauride (Reptilia:
Plesiosauria) aus der Unterkreide (oberes Aptium) von
Kolumbien. – Courier Forschungsinstitut Senckenberg,
145: 1-32.
Hampe, O. (2005): Considerations on a Brachauchenius
skeleton (Pliosauroidea) from the lower Paja Formation
(late Barremian) of Villa de Leyva area (Colombia). –
Fossil Record, 8: 37-51.
h
ampe
, O. (2013): The forgotten remains of a leptocleidid
plesiosaur (Sauropterygia: Plesiosauroidea) from the Ear-
ly Cretaceous of Gronau (Münsterland, Westphalia, Ger-
many). – Paläontologische Zeitschrift, 87 (4): 473 - 491.
Jorquera Grau, a., santos-cuBedo, a., san tisteBan Bové,
c. & G
aloBart
l
orente
, a. (2009): Plesiosaurs (Rep-
eschweizerbart_xxx

226 J. Parrilla-Bel and J.I. Canudo
tilia: Sauropterygia) from the Arcillas de Morella For-
mation (Aptian, Lower Cretaceous) of Castellón (Spain).
– Paleolusitana, 1: 229-235.
k
ear
, B.P. (2005a): A new elasmosaurid plesiosaur from the
Lower Cretaceous of Queensland, Australia. – Journal of
Vertebrate Paleontology, 25 (4): 792-805.
kear, B.P. (2005b): Marine reptiles from the Lower Cre-
taceous (Aptian) deposits of White Cliffs, southeastern
Australia: implications of a high latitude, cold water as-
semblage. – Cretaceous Research, 26: 769 -782.
k
ear
, B.P. & B
arret
t, P.M. (2011): Reassessment of the Lo-
wer Cretaceous (Barremian) pliosauroid Leptocleidus
superstes a
ndrews
, 1922 and other plesiosaur remains
from the nonmarine Wealden succession of southern
England. – Zoological Journal of the Linnean Society,
161 (3): 663 - 691.
kear, B.P., schroeder, N.I. & lee, M.S. (2006): An archaic
crested plesiosaur in opal from the Lower Cretaceous
high-latitude deposits of Australia. – Biology Letters, 2
(4): 615-619.
k
etchum
, H.F. (2007): The anatomy, taxonomy and systema-
tics of three British Middle Jurassic pliosaurs (Sauropte-
rygia: Plesiosauria), and the phylogeny of Plesiosauria.
Unpublished Ph.D. dissertation. – 244 pp.; Cambridge
(Christ’s College, University of Cambridge)
k
etchum
, H.F. (2011): Marine reptiles. – In: B
atten
, D. J.
(Ed.): English Wealden Fossils, 285-294; London (The
Palaeontological Association).
k
etchum
, H.F. & B
enson
, R.B. (2010): Global interrelati-
onships of Plesiosauria (Reptilia, Sauropterygia) and
the pivotal role of taxon sampling in determining the
outcome of phylogenetic analyses. – Biological Reviews,
85 (2): 361-392.
ketchum, H.F. & smith, A.S. (2010): The anatomy and
taxonomy of Macroplata tenuiceps (Sauropterygia,
Plesiosauria) from the Hettangian (Lower Jurassic) of
Warwickshire, United Kingdom. – Journal of Vertebrate
Paleontology, 30 (4): 1069-1081.
k
nutsen
, E.M. (2012): A taxonomic revision of the genus
Pliosaurus (owen, 1841a) owen, 1841b. – Norwegian
Journal of Geology, 92: 259-276.
knutsen, e.m., druckenmiller, p.s. & hurum, J.h. (2012):
Redescription and taxonomic clarification of ‘Tricleidus’
svalbardensis based on new material from the Agardhf-
jellet Formation (Middle Volgian). – Norwegian Journal
of Geology, 92: 175 -186.
l
azo
, D.G. & c
ichowolski
, M. (2003): First plesiosaur re-
mains from the Lower Cretaceous of the Neuquén basin,
Argentina. – Journal Information, 77 (4): 784 -789.
lonGman, H.A. (1924): A new gigantic marine reptile from
the Queensland Cretaceous, Kronosaurus queenslandi-
cus new genus and species. – Memoirs of the Queensland
Museum, 8: 26 -28.
lydekker, R. (1889): Catalogue of the fossil Reptilia and
Amphibia in the British Museum (Natural History). Part
II. Containing the orders Ichthyopterygia and Sauropte-
rygia. – XXI + 307 pp.; London (British Museum, Na-
tu r a l His tor y).
massare, J.A. (1987): Tooth morphology and prey preferen-
ce of Mesozoic marine reptiles. – Journal of Vertebrate
Paleontology, 7 (2): 121-137.
o’keefe, F.R. (2001): A cladistic analysis and taxonomic
revision of the Plesiosauria (Reptilia: Sauropterygia). –
Acta Zoologica Fennica, 213: 1- 63.
o’keefe, f.r. (2002): The evolution of plesiosaur and plio-
saur morphotypes in the Plesiosauria (Reptilia: Sauropte-
rygia). – Paleobiology. 28: 101-112.
o’keefe, F.R. & hiller, N. (2006): Morphologic and ontoge-
netic patterns in elasmosaur neck length, with comments
on the taxonomic utility of neck length variables. – Palu-
dicola, 5 (4): 206 -229
o’keefe, F.R. & wahl, W. Jr (2003): Preliminary report on
the osteology and relationships of a new aberrant crypto-
cleidoid plesiosaur from the Sundance Formation, Wyo-
ming. – Paludicola, 4: 48-68.
owen, R. (1842): Report on British fossil reptiles, Part II. –
Report of the British Association for the Advancement
of Science for 1841, 11: 60-20 4.
owen, R. (1860): On the orders of fossil and recent Repti-
lia, and their distribution through time. – Report of the
British Association for the Advancement of Science, 29:
153 -166.
parrilla-Bel, J., younG, M., puértolas, E., canudo, J.I.,
cruzado-caBallero, P., Gasca, J.M. & moreno-azan-
za, M. (2012): Descripción de un resto craneal de reptil
marino de la Formación Blesa (Barremiense inferior) de
la localidad de Josa (Teruel). – In: liao, J-c., Gám ez
v
intaned
, J.a., v
alenzuela
-r
íos
, J.i. & G
arcía
-f
orner
,
a. (Eds.): XXVIII Jornadas de la Sociedad Española de
Paleontología. Homenaje a Guillem Colom Casasnovas
(1900-1993), 241-243; Universitat de València.
rieppel, o., sander, p.m. & storrs, G.W. (2002): The skull
of the pistosaur Augustasaurus from the Middle Triassic
of northwestern Nevada. – Journal of Vertebrate Paleon-
tology, 22: 577-592.
r
omer
, a.s. & l
ewis
, a.D. (1959): A mounted skeleton of
the giant plesiosaur Kronosaurus. – Breviora, Museum
of Comparative Zoology, 112: 1-15.
r
oyo
-t
orres
, r. & c
oBos
, a. (2008): Vértebra cervical de
Pliosauridae indet. (Albiense-Cenomaniense) de Jaba-
loyas (Teruel). – In: r
uiz
-o
meñaca
, J.i., p
iñuela
, l. &
García-ramos, J.c. (Eds.): Libro de resúmenes. XXIV
Jornadas de la Sociedad Española de Paleontología. Mu-
seo del Jurásico de Asturias (MUJA), Colunga, 15-18 de
octubre de 2008, 187-188; Colunga (Museo del Jurásico
de Ast u r i as).
ruiz-omeñaca, J.I. (2006): Restos directos de dinosaurios
(Saurischia, Ornithischia) en el Barremiense (Cretáci-
co Inferior) de la Cordillera Ibérica en Aragón (Teruel,
España). – PhD, Universidad de Zaragoza; Zaragoza.
ruiz-omeñaca, J.I., canudo, J.I., aurell , M., Badenas, B.,
cuenca-Bescós, G. & ipas, J. (2004): Estado de las inve-
stigaciones sobre los vertebrados del Jurásico superior y
el Cretácico inferior de Galve (Teruel). – Estudios geoló-
gicos, 60: 179 -2 0 2.
s
achs
, S. (2004): Resdescription of Woolungasaurus glendo-
werensis (Plesiosauria: Elasmosauridae) from the Lower
Cretaceous of Northeast Queensland. – Memoirs of the
Queensland Museum, 49 (2): 713-732.
sachs, s. & kear, B.p. (2014/2015): Postcranium of the pa-
radigm elasmosaurid plesiosaurian Libonectes morgani
(welles, 1949). – Geological Magazine, 152 (4): 69 4 -710.
eschweizerbart_xxx

On the presence of plesiosaurs in the Blesa Formation (Barremian) in Teruel (Spain) 227
Published online 2014. DOI: http://dx.doi.org/10.1017/
S0016756814000636
sachs, s. & kear, B.p. (2015): Fossil Focus: Elasmosaurs. –
Palaeontology Online, 5 (2): 1-8.
salas, R., Guimera, J., mas, R., martin-closas, C., melén-
dez, A. & alonso, A. (2001): Evolution of the Mesozoic
central Iberian Rift System and its Cainozoic inversion
(Iberian chain). – Mémoires du Museum national dʼHi-
stoire naturelle, 186: 145-186.
sander, p.m., rieppel, o. & Bucher, H. (1997): A new pisto-
saurid (Reptilia: Sauropterygia) from the Middle Triassic
of Nevada and its implications for the origin of plesio-
saurs. – Journal of Vertebrate Paleontology, 17: 526 -533.
s
antos
-c
uBedo
, a., G
aloBart
, a. & s
antisteBan
, c. (2007):
Where are the Early Cretaceous plesiosaurs? The first
sacral vertebra of Plesiosauria (Reptilia: Sauropterygia)
found in the Arcillas de Morella Formation (Aptian, Ear-
ly Cretaceous) of Eastern Spain. – In: l
iston
, J. (Ed.): 55
Symposium of Vertebrate Palaeontology and Compara-
tive Anatomy and the 16 Symposium of Palaeontological
preparation and conservation, held at The University of
Glasgow, 43.
sato, t., haseGawa, y. & manaBe, m. (2006): A new elas-
mosaurid plesiosaur from the Upper Cretaceous of Fu-
kushima, Japan. – Palaeontology, 49: 467-484.
seeley, H.G. (1877): On Mauisaurus gardneri (seeley ), an
elasmosaurian from the base of the Gault at Folkestone.
– Quarterly Journal of the Geological Society, 33 (1-4):
541-547.
sennikov, a.G. & arkhanGelsky, M.S. (2010): On a typical
Jurassic sauropterygian from the Upper Triassic of Wilc-
zek Land (Franz Josef Land, Arctic Russia). – Paleonto-
logical Journal, 44: 567-572.
s
mith
, A.S. (2013): Morphology of the caudal vertebrae in
Rhomaleosaurus zetlandicus and a review of the evi-
dence for a tail fin in Plesiosauria. – Paludicola, 9 (3):
144-158.
smith, a.s. & Benson, r.B.J. (2014): Osteology of Rhomaleo-
saurus thorntoni (Sauropterygia, Rhomaleosauridae)
from the Lower Jurassic (Toarcian) of Northamptonshire,
England. – Monographs of the Palaeontographical
Society, 168 (642): 1- 40.
s
mith
, A.S. & v
incent
, P. (2010): A new genus of pliosaur
(Reptilia: Sauropterygia) from the Lower Jurassic of
Holzmaden, Germany. – Palaeontology, 53 (5): 1049-
1063.
soria de miGuel, A.R. (1997): La sedimentación en las cuen-
cas marginales del Surco Ibérico durante el Cretácico
Inferior y su control estructural. PhD, Universidad de
Zaragoza (Servicio de Publicaciones de la Universidad
de Zaragoza).
s
torrs
, G.W. (1991): Anatomy and relationships of Corosau-
rus alcovensis (Diapsida: Sauropterygia) and the Triassic
Alcova Limestone of Wyoming. – Peabody Museum of
Natural History Bulletin, 44: 1-151.
t
arlo
, L.B. (1960): A review of Upper Jurassic pliosaurs.
– Bulletin of the British Museum (Natural History),
Geology, 14: 145 -189.
ulloa-rivas, J.A. & canudo, J.I. (2014): New cranial re-
mains of Ornithocheiroidea (Pterosauria) from the Barre-
mian (Lower Cretaceous) of the Iberian Peninsula. – In:
arreGuín-rodriGuez, G., colmenar, J., díaz-Beren-
Guer, E., Galán, J., leGarda-lisarri, A., parrilla-Bel,
J., p
uértolas
-p
ascual
, E. & s
ilva
-c
asal
, R. (Eds.): New
insights on ancient life. – Actas del XII EJIP, 116-119;
Boltaña.
van Beneden, P.J. (1882): Deux plésiosaures du Lias inféri-
eur du Luxembourg. – Mémoires de lʼAcadémie Royale
des Sciences, des Lettres et des Beaux-Arts de Belgique,
1-45.
vincent, P. (2011): A re-examination of Hauffiosaurus zan-
oni, a pliosauroid from the Toarcian (Early Jurassic) of
Germany. – Journal of Vertebrate Paleontology, 31 (2):
34 0 -351.
vincent, p., Bardet, n., houssaye, a., pereda suBerBiola,
X., amaGhzaz, m. & meslouh, s. (2013b): New plesio-
saur specimens from the Maastrichtian Phosphates of
Morocco: implications for niche partitioning in the latest
Cretaceous marine top-predators. – Gondwana Research,
24 (2): 796-805.
vincent, P., Bardet, N. & mattioli, E. (2013a): A new plio-
saurid from the Pliensbachian, Early Jurassic of Norman-
dy, Northern France. – Acta Palaeontologica Polonica,
58 (3): 471-485.
vincent, p., Bardet, n., pereda suBerBiola, X., Bouya, B.,
a
maGhzaz
, m. & m
eslouh
, M.S. (2011): Z arafasaura
oceanis, a new elasmosaurid (Reptilia: Sauropterygia)
from the Maastrichtian Phosphates of Morocco and the
palaeobiogeography of latest Cretaceous plesiosaurs. –
Gondwana Research, 19: 1062 -1073.
v
incent
, p. & t
aquet
, P. (2010): A plesiosaur specimen from
the Lias of Lyme Regis: the second ever discovered plesio-
saur by Mary Anning. – Geodiversitas, 32 (3): 377-390.
w
eGner
, T. (1914): Brancasaurus brancai n. g. n. sp., ein
Elasmosauride aus dem Wealden Westfalens. – In: s
cho
-
endorf, F. (Ed.): Branca-Festschrift, 235-305; Berlin
(Borntraeger).
welles, S.P. (1962): A new species of elasmosaur from the
Aptian of Colombia and a review of the Cretaceous ple-
siosaurs. – University of California Publications in Geo-
logical Sciences, 44: 1-96.
yaGü e, P., orteGa, F., noè, L., Gasulla, J.M. & Ga rcía,
M.D. (2003): Reptiles marinos (Plesiosauria) del Aptien-
se inferior de Morella (Castellón). – Ciencias de la Tierra,
26: 399-404.
Manuscript received: April 13th, 2015.
Revised version accepted by the Stuttgart editor: August 3rd,
2015.
Addresses of the authors:
J
ara
p
arrilla
B
el
, Grupo Aragosaurus-IUCA, Departamen-
to de Ciencias de la Tierra, Facultad de Ciencias, Universidad
de Zaragoza. C/ Pedro Cerbuna 12, 50009 Zaragoza, Spain;
e-mail: jarapb@unizar.es
José iGnacio canudo, Museo de Ciencias Naturales de la
Universidad de Zaragoza. C/ Pedro Cerbuna 12, 50009 Za-
ragoza, Spain & Grupo Aragosaurus-IUCA, Departamento
de Ciencias de la Tierra, Facultad de Ciencias, Universidad
de Zaragoza. C/ Pedro Cerbuna 12, 50009 Zaragoza, Spain;
e-mail: jicanudo@unizar.es
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