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A possible oviraptorosaurid theropod from the Santana Formation (Lower Cretaceous, ?Albian) of Brazil
... However, in recent years a more diverse Late Cretaceous theropod assemblage has been described in other geological units of the country, but still known from mostly fragmentary specimens, including abelisaurids (e.g., Pycnomemosaurus nevesi; Kellner and Campos, 2002;Delcourt, 2017;Delcourt and Grillo, 2017), spinosaurids (e.g., Oxalaia quilombensis; Kellner et al., 2011), probable carcharodontosaurids (Vilas Bôas et al., 1999;Candeiro et al., 2004Candeiro et al., , 2006, megaraptorans (M endez et al., 2012;Martinelli et al., 2013;Sales et al., 2017), and possibly noasaurids (Lindoso et al., 2012) and maniraptorans (Elias et al., 2004;Bittencourt and Langer, 2011). As part of the Early Cretaceous theropod record, Frey and Martill (1995) described a partial sacrum articulated to two caudal vertebrae and a partial right ilium (SMNS 58023) from the Albian beds of the Santana Formation. This specimen was interpreted tentatively as an indeterminate oviraptorosaur on the basis of the presence of pleurocoels in the sacral vertebral centra (Frey and Martill, 1995). ...
... As part of the Early Cretaceous theropod record, Frey and Martill (1995) described a partial sacrum articulated to two caudal vertebrae and a partial right ilium (SMNS 58023) from the Albian beds of the Santana Formation. This specimen was interpreted tentatively as an indeterminate oviraptorosaur on the basis of the presence of pleurocoels in the sacral vertebral centra (Frey and Martill, 1995). Subsequently, considered that the taxonomic assignment of SMNS 58023 should be considered with caution. ...
... SMNS 58023 lacks field data because it was recovered by nonprofessional collectors. However, Frey and Martill (1995) considered the matrix surrounding the specimen as typical of early diagenetic carbonate concretions of the Araripe Basin. Many of these concretions are fossiliferous and often preserve threedimensional fossils (e.g., Martill, 1988;Maisey, 1991;Fara et al., 2005); some of them even preserve soft tissues (e.g., Martill, 1988;Martill et al., 2000). ...
A specimen composed of a partial sacrum articulated to two anterior caudal vertebrae and an ilium (SMNS 58023) from the Lower Cretaceous (Albian) Santana Formation of Brazil was originally described as an oviraptorosaur, but it is here re-interpreted as the oldest megaraptoran of South America. The phylogenetic relationships of SMNS 58023 were tested quantitatively for the first time including it in the two most comprehensive phylogenetic data sets focused on non-maniraptoran theropods –including megaraptorans. The Brazilian specimen was consistently found as a megaraptoran in both analyses because of the presence of sacral centra longer than tall, absence of a median transverse constriction of sacral centra, and the morphology and position of sacral pleurocoels. SMNS 58023 sheds light on a region of the body that is poorly known in megaraptorans and pulls back the temporal range of the clade in South America. This re-interpretation reinforces the absence of oviraptorosaurs in Gondwana.
... Dinosauria. Several theropod dinosaur species have been recognised in the Araripe Basin (Campos and Kellner, 1991;Frey and Martill, 1995;Kellner, 1996aKellner, ,b, 1999Kellner and Campos, 1996;Martill et al., 1996Sues et al., 2002); all come from the concretions of the Romualdo Member. Irritator challengeri Martill et al., 1996, and its probable junior synonym Angaturama limai Kellner, 1996b, represent spinosaurids, a distinctive group of theropods typified by Spinosaurus from North Africa (Stromer, 1934). ...
... The Santana Formation Mirischia probably represents the youngest compsognathid dinosaur yet reported. Frey and Martill (1995) tentatively referred a series of dinosaurian sacral vertebrae from the Santana Formation to the Oviraptorosauria. Although this group is well known from the upper Upper Cretaceous (SantonianeMaastrichtian) of Asia and North America (Barsbold et al., 1990), there have been a few reports of oviraptorosaurians, or their sister group the Therizinosauroidea, in Lower Cretaceous strata (e.g. ...
... Although no substantial remains of oviraptorosaurs and therizinosaurs have been recorded from South America, Frankfurt and Chiappe (1999) tentatively assigned a cervical vertebra from the Upper Cretaceous of Argentina to Oviraptorosauria. Despite this, Naish et al. (2004) found no grounds for referring the Santana Formation vertebrae described by Frey and Martill (1995) to the oviraptorosauria. Thus, this group of dinosaurs currently has no relevance to the age debate of the Santana Formation. ...
This paper is concerned with the famous fossil-bearing carbonate concretions of the Romualdo Member of the Santana Formation Konservat Lagerstätten of north-east Brazil. This palaeontologically important horizon was first dated as Cretaceous by the French palaeoichthyologist Louis Agassiz on the basis of fish fossils obtained by Bavarian explorers Spix and Martius between 1817 and 1820 and Scottish botanist and explorer George Gardner between 1836 and 1841. Gardner equated the concretion level with the English Albian ‘Upper Greensands’ on the basis of an imagined similarity of stratigraphic sequence with that of the Isle of Wight, southern England. Since then high precision dating of this remarkable deposit has proved elusive and the concretion-bearing part of the Santana Formation has been variously dated as early Late Cretaceous or late Early Cretaceous. Attempts at greater precision over the last 30 years have cited its age variously as Aptian, Albian or possibly Cenomanian, but few reliable data have been presented to support these dates.
... It has yielded a diverse and exceptionally well preserved assemblage (Martill and Unwin, 1989;Kellner and Tomida, 2000). It is less well known that this deposit also produces rare dinosaur remains (Campos and Kellner, 1991;Frey and Martill, 1995;Kellner, 1996a). Crocodyliforms and turtles also occur (Gaffney and Meylan, 1991;Martill, 1993;Hirayama, 1998), but these are rare. ...
... Beginning in the mid-1990s, several theropods were reported and described. Among the first of these was the partial sacrum of a coelurosaur, described by Frey and Martill (1995). They suggested, on the basis of its pleurocoelous centra, that it had affinities with Oviraptorosauria. ...
... The referral of a theropod sacrum from the Santana Formation to Oviraptorosauria by Frey and Martill (1995) is also biogeographically significant, if this assignment proves to be correct. Thus far, there are only two other reports of members of Oviraptorosauria from Gondwana: a surangular and a dorsal vertebra from the Early Cretaceous of Australia (Currie et al., 1996), and an isolated cervical vertebra from the Late Cretaceous of Argentina (Frankfurt and Chiappe, 1999). ...
Associated well-preserved, uncrushed skeletal remains, comprising the pelvic girdle, partial sacrum, both femora, and parts of the right tibia and fibula, from the Romualdo Member of the Lower Cretaceous Santana Formation of northeastern Brazil record the presence of a previously unknown coelurosaurian theropod dinosaur in that formation. The pelvic girdle is noteworthy for the bilaterally asymmetrical development of various bony features. The specimen also preserves a segment of lithified intestinal tract. While still in the matrix, the fossil preserved a vacuity behind the pubic apron that may indicate the existence of a postpubic air sac.
... It has yielded a diverse and exceptionally well preserved assemblage (Martill and Unwin, 1989;Kellner and Tomida, 2000). It is less well known that this deposit also produces rare dinosaur remains (Campos and Kellner, 1991;Frey and Martill, 1995;Kellner, 1996a). Crocodyliforms and turtles also occur (Gaffney and Meylan, 1991;Martill, 1993;Hirayama, 1998), but these are rare. ...
... Beginning in the mid-1990s, several theropods were reported and described. Among the first of these was the partial sacrum of a coelurosaur, described by Frey and Martill (1995). They suggested, on the basis of its pleurocoelous centra, that it had affinities with Oviraptorosauria. ...
... The referral of a theropod sacrum from the Santana Formation to Oviraptorosauria by Frey and Martill (1995) is also biogeographically significant, if this assignment proves to be correct. Thus far, there are only two other reports of members of Oviraptorosauria from Gondwana: a surangular and a dorsal vertebra from the Early Cretaceous of Australia (Currie et al., 1996), and an isolated cervical vertebra from the Late Cretaceous of Argentina (Frankfurt and Chiappe, 1999). ...
Although rare, dinosaurs are well preserved in calcareous nodules of the Santana Formation (Early Cretaceous, ?Albian) of the Araripe Basin, in northeastern Brazil. So far, including only a spinosauroid and three coelurosaurs, the dinosaur fauna appears depauperate. High theropod diversity in assemblages where other dinosaurs are rare or absent is not unique to the Santana Formation. It is seen also in several other assemblages, including Solnhofen and the Maevarano Formation of Madagascar. We consider several factors, including the occurrence of intraguild predation, the possibility that small theropods could subsist in marginal environments, and reliance on coastal resources, that may have been responsible for this apparent ecological imbalance. A new coelurosaur from the Santana Formation, here formally named Mirischia asymmetrica, is shown to be distinct from Santanaraptor placidus [Kellner, A.W.A. (199930.
Kellner , AWA . 1999. Short note on a new dinosaur (Theropoda, Coelurosauria) from the Santana Formation (Romualdo Member, Albian) northeastern Brazil. Boletim do Museu Nacional, Nova Serie, Rio de Janeiro, Brasil, 49: 1–8. View all references) “Short note on a new dinosaur (Theropoda, Coelurosauria) from the Santana Formation (Romualdo Member, Albian) northeastern Brazil”, Boletim do Museu Nacional, Nova Serie, Rio de Janeiro, Brasil 49, 1–8]. Other theropods from the Santana Formation are briefly reviewed. Mirischia is a compsognathid, more similar to the European Compsognathus than to the Asian Sinosauropteryx.
... The only evidence of Aves from that geologic time in the country are feathers, all from the Early Cretaceous Crato Member (Aptian) of the Santana Formation, Araripe Basin (Figs 17-19). Several kinds (most undescribed) have been recovered, among which one flight feather (Martins Neto & Kellner 1988, semiplumes (Martill & Figueira 1994), down feathers , and some contour feathers, a few showing the color pattern (Martill & Frey 1995, Kellner et al. 1999b. All have been regarded as avian, but the recent discoveries of feathered dinosaurs cast some doubts about those identifications. ...
... Down feather (Kellner et al. 1994, Fig. 17). Contour feathers with color pattern (Martill & Frey 1995, Kellner et al. 1999b). ...
... Theropoda, Spinosauridae Irritator challengeri Martill et al. 1996 (see also Kellner 1996b) Angaturama limai Kellner and Campos 1996 Theropoda, Coelurosauria Santanaraptor placidus Kellner 1999 Dinosauria indet. One fragmentary bone (Leonardi & Borgomanero 1981, Kellner 1996b Incomplete sacrum (Frey & Martill 1995, Kellner 1996b 8. Vieira locality in Sobradinho, Municipality of Porteiras (Campos 1985) Theropoda indet. Incomplete vertebrae (Campos 1985) Pelvis and other remains (Campos & Kellner 1991) Unfortunately, no detailed data is available for the exact dinosaur sites of the Romualdo Member (Santana Formation), which outcrops in several areas in the states of Ceará, Pernambuco, and Piauí. ...
Dinosaur research is developing at very high rates around the world resulting in several new discoveries that are improving our understanding of this terrestrial reptilian clade. Except for the last couple years, the studies of Brazilian dinosaurs have not followed this expansive trend, despite the high potential of several dinosaur localities. So far there are only eight described taxa, four in the last year, representing theropod, sauropod, and one possible prosauropod taxa. Except for footprints, there are no records of ornithischian dinosaurs in the country what is at least partially explainable by the lack of continuous vertebrate fossil collecting program in the country. More funding is necessary to improve the research activities in this field.
... Although these structures may appear to be of biological origin (superficially resembling coccoid microbial bodies or autolithified bacteria (Wuttke, 1983;Frey and Martill, 1995;Briggs, 2003) Bacteria by Frey and Martill, 1995 re-interpreted as melanin bodies by Vinther et al. (2008)), they may better be interpreted as preservational fabrics produced during the fossilization process, on account of their external similarity to oxidised pyrite framboids and pseudoframboids (Berner, 1970(Berner, , 1984Ohfuji and Rickard, 2005). However, these structures differ in two key aspects that separate them from framboids and pseudoframboids: the lack of discrete euhedral crystals, and the lack of an ordered (in the case of true framboids), disordered or massive (in the case of pseudoframboids) internal texture (Berner, 1970(Berner, , 1984Ohfuji and Rickard, 2005). ...
... Although these structures may appear to be of biological origin (superficially resembling coccoid microbial bodies or autolithified bacteria (Wuttke, 1983;Frey and Martill, 1995;Briggs, 2003) Bacteria by Frey and Martill, 1995 re-interpreted as melanin bodies by Vinther et al. (2008)), they may better be interpreted as preservational fabrics produced during the fossilization process, on account of their external similarity to oxidised pyrite framboids and pseudoframboids (Berner, 1970(Berner, , 1984Ohfuji and Rickard, 2005). However, these structures differ in two key aspects that separate them from framboids and pseudoframboids: the lack of discrete euhedral crystals, and the lack of an ordered (in the case of true framboids), disordered or massive (in the case of pseudoframboids) internal texture (Berner, 1970(Berner, , 1984Ohfuji and Rickard, 2005). ...
... Although these structures may appear to be of biological origin (superficially resembling coccoid microbial bodies or autolithified bacteria (Wuttke, 1983;Frey and Martill, 1995;Briggs, 2003) Bacteria by Frey and Martill, 1995 re-interpreted as melanin bodies by Vinther et al. (2008)), they may better be interpreted as preservational fabrics produced during the fossilization process, on account of their external similarity to oxidised pyrite framboids and pseudoframboids (Berner, 1970(Berner, , 1984Ohfuji and Rickard, 2005). However, these structures differ in two key aspects that separate them from framboids and pseudoframboids: the lack of discrete euhedral crystals, and the lack of an ordered (in the case of true framboids), disordered or massive (in the case of pseudoframboids) internal texture (Berner, 1970(Berner, , 1984Ohfuji and Rickard, 2005). ...
... Although these structures may appear to be of biological origin (superficially resembling coccoid microbial bodies or autolithified bacteria (Wuttke, 1983;Frey and Martill, 1995;Briggs, 2003) Bacteria by Frey and Martill, 1995 re-interpreted as melanin bodies by Vinther et al. (2008)), they may better be interpreted as preservational fabrics produced during the fossilization process, on account of their external similarity to oxidised pyrite framboids and pseudoframboids (Berner, 1970(Berner, , 1984Ohfuji and Rickard, 2005). However, these structures differ in two key aspects that separate them from framboids and pseudoframboids: the lack of discrete euhedral crystals, and the lack of an ordered (in the case of true framboids), disordered or massive (in the case of pseudoframboids) internal texture (Berner, 1970(Berner, , 1984Ohfuji and Rickard, 2005). ...
Fossil insects from the Lower Cretaceous (Aptian) Crato Formation of north-east Brazil are preserved as goethite replacements in laminated limestones of lacustro-lagoonal origin. They display remarkable degrees of morphological detail down to the macromolecular level in some examples. We document the fidelity of preservation and reveal an astonishing variety of morphological detail comparable in some instances with that found in amber inclusions.
[This paper was in press in 2014, but published in 2015. Please see my profile for a PDF of the published version]
... So far, more than 30 genera of Oviraptoridae have been described, forming a monophyletic group that is geographically constrained in East Asia (Fig. 1). Although there were three supposed oviraptorosaurs reported from Argentina (Frankfurt and Chiappe 1999), Australia and Brazil (Frey and Martill 1995), all of them were re-examined and reinterpreted as pertaining to other theropod dinosaur taxa. A recent study by Funston et al. (2018) reviewed the discoveries of oviraptorid dinosaurs from the Nemegt Basin. ...
Among all of the dinosaurs, the Late Cretaceous oviraptorosaurs, in addition to troodontid dinosaurs, boast the best fossil records ranging from numerous eggs and embryos, seven clutch–adult associations, highly organized egg clutches, two gravid adults and possible colonial nesting grounds, to plenty of species described from skeletons from East Asia. These well-preserved fossils provided insights into the reproductive biology, ecology, behaviour and developmental biology of oviraptorid dinosaurs, contributing to several groundbreaking palaeontological discoveries in the last decade. Some of them received further support, while the others remain controversial, indicating that a comprehensive, rigorous re-examination using all available evidence is required. In a recent review, oviraptorosaurs were considered as an intermediate stage in moving towards the modern avian reproduction, whose reproductive biology can be inferred based on the avian model. With the new insights generated from the shell histology of several embryo-containing eggs and evidence from previous studies, this study offers a synthetic view of the reproductive biology of the Late Cretaceous oviraptorosaurs, illuminating the peculiar reproductive biology of oviraptorosaurs. In conclusion, oviraptorosaurs had an essentially unique reproductive biology lacking modern analogies. Thus, simply applying either avian or reptilian models to infer the biology of extinct animals appears inappropriate in the case of oviraptorosaurs.
... The first studies in Brazil that attributed vertebrate fossil remains to dinosaurs were published in the nineteenth and midtwentieth centuries (Marsh, 1869;Derby, 1890;Mawson and Woodward, 1907;Price, 1960Price, , 1961. Since that time, dinosaur fossils have been recorded from three principal localities and ages in Brazil: the Triassic of the Santa Maria and Caturrita formations (Langer et al., 2007a), the mid-Cretaceous of the Araripe, Triufo and São Luís-Grajaú basins (Frey and Martill, 1995;Kellner, 1996aKellner, , b, 1999Medeiros et al., 2007;Carvalho et al., 2017), and the Upper Cretaceous of the Bauru and Parecis groups (Franco-Rosas et al., 2004;Kellner et al., 2004;Brusatte et al., 2017). ...
The theropod record from the Cretaceous of northeastern Brazil are rare and consist mostly of isolated and incomplete remains, with only four species described. Here we describe, identify and evaluate the diversity of theropod materials from the Albian-Cenomanian Açu Formation, Potiguar Basin. The material consists of seven isolated theropod vertebrae and a tooth. We identify the material as belonging to four theropod groups: Spinosauroidea, Carcharodontosauria, Megaraptora, and Maniraptora. One of the significant results is the occurrence of Megaraptora in the Potiguar Basin; based on the general morphology, some of the bones we describe are very similar to those of Aerosteon and Megaraptor. Another unexpected result is the identification and presence of a maniraptoran caudal vertebrae; these dinosaurs are very rare in Brazil, with few fossils previously described. Furthermore, we identify other groups that have already been found in isochronous basins of the Northeast region of Brazil and Africa, including Carcharodontosauria and Spinosauroidea. The presence of these theropod groups in the Açu Formation reveals a dinosaur richness in in the Potiguar Basin similar to isochronous basins in Northern Africa and increases knowledge about the diversity of South American dinosaurs.
... The only other theropod clade in which pneumatic mid-caudal vertebrae have been reported, Oviraptorosauria, is unlikely to be a candidate for the affinities of this centrum as the group is likely to have been entirely absent from Gondwana. Restudy of previous material referred to Oviraptorosauria from South America [97,98] has concluded that they are representative of noasaurids and megaraptorans respectively [99,100]. ...
... The only other theropod clade in which pneumatic mid-caudal vertebrae have been reported, Oviraptorosauria, is unlikely to be a candidate for the affinities of this centrum as the group is likely to have been entirely absent from Gondwana. Restudy of previous material referred to Oviraptorosauria from South America [107,108] has concluded that they are representative of noasaurids and megaraptorans, respectively [109,110]. ...
The limited fossil record of Australian Cretaceous theropods is dominated by megaraptorids, reported from associated and isolated material from the Early Cretaceous of Victoria and the ‘Mid’-Cretaceous of central-north New South Wales and central Queensland. Here, we report on new postcranial theropod material from the early Late Cretaceous Griman Creek Formation at Lightning Ridge. Among this new material is an associated set consisting of two anterior caudal vertebrae and a pubic peduncle of the ilium, to which a morphologically similar partial vertebral centra from a separate locality is tentatively referred. These elements display a combination of characteristics that are present in megaraptorid and carcharodontosaurid theropods, including camellate internal organization of the vertebral centra, ventrally keeled anterior caudal centra and a pubic peduncle of the ilium with a ventral surface approximately twice as long anteroposteriorly as mediolaterally wide. Unfortunately, a lack of unambiguous synapomorphies precludes accurate taxonomic placement; however, avetheropodan affinities are inferred. This new material represents the second instance of a medium-sized theropod from this interval, and only the third known example of associated preservation in an Australian theropod. Additional isolated theropod material is also described, including an avetheropodan femoral head that shows similarities to Allosaurus and Australovenator, and a mid-caudal vertebral centrum bearing pneumatic foraminae and extensive camellae that is referrable to Megaraptora and represents the first axial skeletal element of a megaraptorid described from Lightning Ridge.
... II, fig. 8) and an unnamed megaraptoran from the Lower Cretaceous of Brazil (SMNS 58023; Frey and Martill, 1995;Aranciaga Rolando et al., 2018). Nevertheless, the apparent distinctions of Tratayenia from these three forms may be due, at least in part, to the differing positions of the centra preserved in their respective sacral series. ...
We describe Tratayenia rosalesi gen. et sp. nov., a new megaraptoran theropod dinosaur from the Upper Cretaceous of Patagonia, Argentina. The holotype consists of a well-preserved, mostly articulated series of dorsal and sacral vertebrae, two partial dorsal ribs, much of the right ilium, and pubis and ischium fragments. It was found in a horizon of the Upper Cretaceous (Santonian) Bajo de la Carpa Formation of the Neuquén Group in the Neuquén Basin exposed near the town of Añelo in Neuquén Province of northwestern Patagonia. Phylogenetic analysis recovers Tratayenia within the Gondwanan megaraptoran subclade Megaraptoridae. The new taxon exhibits similarities to other megaraptorids such as Aerosteon riocoloradensis, Megaraptor namunhuaiquii, and Murusraptor barrosaensis, but also presents differences in the architecture of the dorsal and sacral vertebrae and the morphology of the ilium. Tratayenia is the first megaraptoran that unequivocally preserves the complete sequence of sacral vertebrae, thereby increasing knowledge of the osteology of the clade. Moreover, depending on the chronostratigraphic ages of the stratigraphically controversial megaraptorids Aerosteon and Orkoraptor burkei, as well as the phylogenetic affinities of several fragmentary specimens, the new theropod may be the geologically youngest megaraptorid or megaraptoran yet discovered. Tratayenia is also the largest-bodied carnivorous tetrapod named from the Bajo de la Carpa Formation, reinforcing the hypothesis that megaraptorids were apex predators in southern South America from the Turonian through the Santonian or early Campanian, following the extinction of carcharodontosaurids.
... Oviraptorosauria is a well-supported clade of small to large (1-8m long) theropods easily recognized by their short skulls with parrot-like beaks, forelimbs with elongated manual fingers, and short tails Osmólska et al. 2004;Balanoff et al. 2009;Longrich et al. 2010;Balanoff & Norell 2012;Lamanna et al. 2014; Figure 13C). Oviraptorosaurs are restricted to the Cretaceous of Asia, North America and possibly South America (Frey & Martill 1995;Frankfurt & Chiappe 1999; for a different opinion, see Agnolín & Martinelli 2007), and most taxa come from Campanian-Maastrichtian deposits. Members of this clade were partially to strictly herbivorous coelurosaurs who adopted an avian-like brooding posture on their nests Varricchio et al. 2008;Zanno & Makovicky 2011). ...
Theropods form a taxonomically and morphologically diverse group of dinosaurs that include extant birds. Inferred relationships between theropod clades are complex and have changed dramatically over the past thirty years with the emergence of cladistic techniques. Here, we present a brief historical perspective of theropod discoveries and classification, as well as an overview on the current systematics of non-avian theropods. The first scientifically recorded theropod remains dating back to the 17th and 18th centuries come from the Middle Jurassic of Oxfordshire and most likely belong to the megalosaurid Megalosaurus. The latter was the first theropod genus to be named in 1824, and subsequent theropod material found before 1850 can all be referred to megalosauroids. In the fifty years from 1856 to 1906, theropod remains were reported from all continents but Antarctica. The clade Theropoda was erected by Othniel Charles Marsh in 1881, and in its current usage corresponds to an intricate ladder-like organization of textquoteleftfamilytextquoteright to textquoteleftsuperfamilytextquoteright level clades. The earliest definitive theropods come from the Carnian of Argentina, and coelophysoids form the first significant theropod radiation from the Late Triassic to their extinction in the Early Jurassic. Most subsequent theropod clades such as ceratosaurs, allosauroids, tyrannosauroids, ornithomimosaurs, therizinosaurs, oviraptorosaurs, dromaeosaurids, and troodontids persisted until the end of the Cretaceous, though the megalosauroid clade did not extend into the Maastrichtian. Current debates are focused on the monophyly of deinonychosaurs, the position of dilophosaurids within coelophysoids, and megaraptorans among neovenatorids. Some recent analyses have suggested a placement of dilophosaurids outside Coelophysoidea, Megaraptora within Tyrannosauroidea, and a paraphyletic Deinonychosauria with troodontids placed more closely to avialans than dromaeosaurids.
... Oviraptorosauria is a clade comprising small− to medium− sized Cretaceous theropod dinosaurs generally characterized by a highly modified and extensively pneumatized skull, toothless jaws, and a rather standard theropod postcranium ). Oviraptorosaurs are known from Laurasia, although a few supposedly oviraptorosaur fossils have also been reported from Gondwana (Frey and Martil 1995;Currie et al. 1996;Frankfurt and Chiappe 1999). In the adequately known advanced oviraptorosaurs, assigned to the family Oviraptoridae, the preorbital part of the skull is strongly shortened and deep, and sometimes there is a me− dian crest along the skull roof. ...
Oviraptorosauria is a clade of Cretaceous theropod dinosaurs of uncertain affinities within Maniraptoriformes. All previous phylogenetic analyses placed oviraptorosaurs outside a close relationship to birds (Avialae), recognizing Dromaeosauridae or Troodontidae, or a clade containing these two taxa (Deinonychosauria), as sister taxon to birds. Here we present the results of a phylogenetic analysis using 195 characters scored for four outgroup and 13 maniraptoriform (ingroup) terminal taxa, including new data on oviraptorids. This analysis places Oviraptorosauria within Avialae, in a sister-group relationship with Confuciusornis. Archaeopteryx, Therizinosauria, Dromaeosauridae, and Ornithomimosauria are successively more distant outgroups to the Confuciusornis–oviraptorosaur clade. Avimimus and Caudipteryx are successively more closely related to Oviraptoroidea, which contains the sister taxa Caenagnathidae and Oviraptoridae. Within Oviraptoridae, “Oviraptor” mongoliensis and Oviraptor philoceratops are successively more closely related to the Conchoraptor–Ingenia clade. Oviraptorosaurs are hypothesized to be secondarily flightless. Emended phylogenetic definitions are provided for Oviraptoridae, Caenagnathidae, Oviraptoroidea, Oviraptorosauria, Avialae, Eumaniraptora, Maniraptora, and Maniraptoriformes.
... However, we note that no troodontids, ornithomimids, or indeed members of the Arctometatasalia have previously been reported from South America. Frey & Martill (1995) have reported on a dinosaurian synsacrum from the Santana Formation with pleurocoels, and suggested it may have affinities with the Oviraptosauridae. Holtz (1994) notes that pleurocoels are present in the dorsal vertebrae of the Bullatosauria. ...
The skull of a new, and highly unusual crested dinosaur with an elongate rostrum is the first dinosaur to be named from the Santana Formation of NE Brazil. Irritator challengeri gen. et sp. nov was most likely a maniraptoran dinosaur, but its affinities to other maniraptorans remain to be established. Unique features for Irritator include the pattern of tooth replacement, a highly reduced supratemporal fenestra, extreme lateral compression of the rostrum and a saggital crest comprised of the frontal and parietal bones. Irritator was most probably a piscivore. A land link between South America and the dinosaurian faunal province of North America and Asia is indicated, probably via Africa.
... Early Cretaceous dinosaurs have been reported from the Hauterivian-Barremian of the La Amarga Formation of Neuquén, from which the dicraeosaurid sauropod Amargasaurus, the small, probable abelisaurian theropod Ligabueno, and an undetermined stegosaur have been described (Salgado & Bonaparte, 1991;Bonaparte, 1996). Several theropods have recently been reported from the Santana Formation (Aptian) of Brazil, including spinosaurids (Kellner & Campos, 1996;Martill et al., 1996) and coelurosaurs (Frey & Martill, 1995;Kellner, 1999;Martill et al., 2000). Some theropod material of Aptian age, including two partial skeletons of an undescribed carcharodontosaurid, have also been reported from the Chubut Group of Argentina (Rich et al., 2000). ...
Some fragmentary dinosaur remains from the uppermost Hauterivian–Barremian La Paloma Member of the Cerro Barcino Formation of northern Chubut, Argentina are described. Together with the fauna from the La Amarga Formation of Neuquén, Argentina, this material represent the oldest known Cretaceous dinosaur fauna from South America. It includes remains of a probable titanosaurian sauropod and an abelisaurian, probable abelisaurid, theropod. This is the oldest record of titanosaurs from South America and the oldest record of abelisaurids globally. The presence of both small-bodied noasaurids in the La Amarga Formation and medium-sized–large abelisaurids in the Cerro Barcino Formation, in the middle Lower Cretaceous of Argentina, indicates that abelisaurian diversification began well before the final fragmentation of Gondwana. Whereas this explains the wide distribution of abelisaurs in the Late Cretaceous, reasons other than vicariance must be invoked for their apparent absence in the 'middle' Cretaceous of Africa.
... The caudal facet is rounded and expands slightly below the ventral margin of the cranial facet ( Figure 3 Sacral foramina have not been reported in basal pseudosuchians, non-dinosaurian dinosauriforms and other basal dinosaurs, but pleurocoels were described for tetanuran theropods (Rauhut 2003;O'Connor 2006). Yet, these are much larger and less numerous (Frey and Martill 1995;Harris 1998), and the multiple foramina of UFPel 014 seem unique among early saurischians. ...
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... Additionally, oviraptorosaur remains have also been recognized in at least three different localities from Gondwana. The first mention was made by Frey and Martill (1995) based on an incomplete sacrum from the Aptian Santana Formation in the Araripe Basin (Brazil). Later on, an isolated cervical vertebra from the Maastrichtian Lecho Formation in northwestern Argentina was interpreted as belonging to an indeterminated oviraptorosaur (Frankfurt and Chiappe, 1999). ...
In this contribution a putative oviraptorosaurian cervical vertebra discovered in the Campanian-Maastrichtian El Brete Formation from Salta Province, NW Argentina is analysed. Based on the resemblances of this vertebra with those of the basal neoceratosaurian Elaphrosaurus and with the noasaurid Noasaurus, the Salta specimen is interpreted to belong to the third or fourth cervical vertebra of a Noasauridae (eventually Noasaurus). Furthermore, it is suggested that the supposed anterior cervical vertebrae of Masiakasaurus, Laevisuchus and Noasaurus possibly correspond to a more posterior position than previously considered. Contrary to abelisaurids, the morphology of the anterior cervical vertebrae of noasaurids indicates that they probably were long neck theropods resembling ornithomimid coelurosaurs. Therefore, the occurrence of oviraptorosaurs in Argentina is rejected.
Megaraptorid theropods thrived in South America and Australia during the mid-Cretaceous. Their Australian record is currently limited to the upper Barremian–lower Aptian upper Strzelecki Group and the upper Aptian–lower Albian Eumeralla Formation of Victoria, the Cenomanian Griman Creek Formation of New South Wales, and the Cenomanian–lowermost Turonian Winton Formation of Queensland. The latter has produced Australovenator wintonensis, the stratigraphically youngest and most complete Australian megaraptorid. The Eric the Red West (ETRW) site on Cape Otway, Victoria (Eumeralla Formation; lower Albian), has yielded two teeth, two manual unguals, and a right astragalus that are almost identical to the corresponding elements in Australovenator. Herein, we classify these as Megaraptoridae cf. Australovenator wintonensis. We also reappraise the ‘spinosaurid’ cervical vertebra from ETRW and suggest that it pertains to Megaraptoridae. Three other theropod elements from ETRW—a cervical rib (preserving a bite mark), a caudal vertebra, and a non-ungual manual phalanx—are also described, although it is not possible to determine their phylogenetic position more precisely than Tetanurae (non-Maniraptoriformes). All elements were found in a fluvial deposit, associated with isolated bones of other theropods, ornithopods, and turtles, amongst others; consequently, no two can be unequivocally assigned to the same theropod individual. The new specimens from ETRW demonstrate that a megaraptorid theropod morphologically similar to Australovenator lived during the late Early Cretaceous in Victoria, at a higher paleolatitude than its northern counterpart. Moreover, they attest to the success of megaraptorids in late Barremian–early Turonian faunas throughout eastern Australia.
Introduction Remains of possible birds are extremely rare in the Crato Formation and have so far only been reported from the Nova Olinda Member. The first report was of an isolated probable remex (Figure 18.1a) described by Martins-Neto and Kellner (1988), and subsequently refigured by Kellner et al. (1991) and Kellner (2002). Martill and Filgueira (1994) later described a semiplume, while Kellner et al. (1994) reported the occurrence of an isolated down feather. Several other feathers have since been reported from the Crato Formation (Kellner, 2002). Avian skeletal remains, although known from anecdotal accounts and personal observations, have yet to be reported in the literature and two examples are figured here for the first time (Plate 25d, Plate 26). Isolated feathers occur in both the weathered, buff-coloured laminated limestone as goethite pseudomorphs, and as carbonaceous replicas in the unweathered limestones. Specimens preserved as carbonaceous replicas may be represented by bacterial autolithifications (Martill and Frey, 1995), and in this respect the preservation mirrors that of the famous soft-tissue fossils of the Eocene Messel Formation of Germany (Wuttke, 1983). As in the case of the Crato Formation insects, fine details may be preserved in the feathers, despite the bacterial autolithification. In some cases colour patterns appear to have been preserved; in most instances as dark and light transverse bands (Plate 25). Although it has been possible to categorize these isolated feathers by comparison with modern feather morphotypes, it has not been possible to assign them to any particular taxon.
To date the dinosaur record in Brazil is limited to saurischians and no confirmed evidence (except probably footprints) of ornithischians is presently known. Two dinosaur taxa were described from the Triassic Santa Maria Formation: Spondylosoma absconditum and Staurikosaurus pricei. The dinosaurian affinities of Spondylosoma are questioned in the literature; Staurikosaurus is regarded by some authors as closely related to Herrerasaurus from Argentina. No Jurassic dinosaurs are known from Brazil, but there are several Cretaceous occurrences. Titanosaurid sauropods (Antarctosaurus brasiliensis, several undescribed postcranials and teeth) and theropods (teeth) are present in the Late Cretaceous strata of the Bauru Group. Spinosaurid theropods have been found in the Albian strata of northeast Brazil and are apparently closely related to some African forms. This distribution pattern may be a product of an Early Cretaceous vicariant event. Spinosaurids as regarded here are not an exclusive Gondwanan group and are also present in Europe (Baryonyx). A literal interpretation of the stratigraphic record, therefore, suggests that dinosaur faunal interchanges between Europe and Gondwana may have occurred not only from South to North as previously supposed, but in the opposite direction as well. This hypothesis is very preliminary and can be tested by new and more complete dinosaur material from Brazil and Africa.
The holotype of Microvenator celer Ostrom, 1970 (AMNH 3041) is a partial skeleton of a small maniraptoran theropod from the Lower Cre-taceous Cloverly Formation of Montana. We present a detailed redescription of this specimen, emphasizing those features that are of interest for discovering the phylogenetic relationships of Mi-crovenator. Based on several postcranial features, especially the lack of fusion of the neurocentral sutures, we consider AMNH 3041 a juvenile individual. Reexamination of the holotype revealed the presence of several autapomorphies that provide the basis for a revised diagnosis of Micro-venator celer. Diagnostic characters include posterior dorsal and caudal vertebrae 'that are wider than high, the presence of a deep depression on the proximomedial part of the pubis, and an accessory trochanteric ridge below the lesser fem-oral trochanter. Phylogenetic analysis places Mi-crovenator either among Oviraptorosauria, or as the sister group to the Oviraptorosauria. Among the characters diagnostic for the Oviraptorosauria, anteriorly concave pubes, a proximodorsal tuber-cle on the manual unguals, and possibly an eden-tulous dentary with a pronounced symphysis are present in Microvenator. M. celer is the earliest known oviraptorosaurian or oviraptorosaur-like theropod represented by diagnostic skeletal remains .
Upper Jurassic and Lower Cretaceous sedimentary layers are represented in the Brazilian Paran�a Basin by
the fluvioeaeolian Guar�a Formation and the Botucatu Formation palaeoerg, respectively, overlapped by
the volcanic Serra Geral Formation. In Uruguay, the corresponding sedimentary units are named Batoví
and Rivera Members (both from the Tacuaremb�o Formation), and the lava flows constitute the Arapey
Formation (also in Paran�a Basin). Despite the lack of body fossils in the mentioned Brazilian formations,
Guar�a/Batoví dinosaur fauna is composed of theropod, ornithopod and wideegauge sauropod tracks and
isolated footprints, as well as theropod teeth. In turn, the Botucatu/Rivera dinosaur fauna is represented
by theropod and ornithopod ichnofossils smaller than those from the underlying units. The analysis of
these dinosaur ichnological records and comparisons with other global Mesozoic ichnofauna indicates
that there is a size reduction in dinosaur fauna in the more arid Botucatu/Rivera environment, which is
dominated by aeolian dunes. The absence of sauropod trackways in the Botucatu Sandstone fits with the
increasingly arid conditions because it is difficult for heavy animals to walk on sandy dunes, as well as to
obtain the required amount of food resources. This comparison between the Upper Jurassic and Lower
Cretaceous dinosaur fauna in south Brazil and Uruguay demonstrates the influence of aridization on the
size of animals occupying each habitat.
The disappearance of nonavian dinosaurs is only a small part of a greater class of extinctions known as “mass extinctions.” Mass extinctions are global events characterized by unusually high rates of extinction. The five episodes of mass extinctions in Earth history are the Permo-Triassic extinction, the Late Ordovician extinction, the Late Devonian extinction, the Triassic-Jurassic extinction, and the Cretaceous-Tertiary (K/T) extinction. This chapter focuses on patterns of geologic and biotic changes that occurred during the Cretaceous-Tertiary (K/T) extinction. It also highlights the similarities and differences in interpretations of geologic and fossil records. It concludes with two scenarios explaining the differing views about dinosaur extinction.
Dinosaurs are one of the most dominant groups in Cretaceous reptilian faunas. A summary of their record in northern Brazil and northern Africa during the middle of the Cretaceous Period (Aptian-Cenomanian) is presented here. Dinosaurs are represented by 32 species (three ornithischians, six sauropods and 23 theropods) from Brazil, Egypt, Lybia, Morocco, Niger, Sudan and Tunisia. These dinosaur assemblages provide fundamental data about distribution and composition of sauropods and theropods in northern Gondwana during the middle of the Cretaceous Period and confirm these assemblages to be among the most important dinosaur faunas in the north Gondwana areas.
The Early Cretaceous Otway and Strzelecki Groups exposed on the southern coast of Victoria, Australia, have produced a fauna of dinosaurs that lived within the Antarctic Circle. As many as five or six species of hypsilophodontids numerically dominate the collections from there, but the rarer and more fragmentary theropod remains suggest a surprising diversity of carnivorous dinosaurs. A possible surangular and an isolated vertebra have characters considered diagnostic for Late Cretaceous oviraptorosaurs of the Northern Hemisphere. Other fossils suggest the presence of ornithomimosaurs, dromaeosaurids and neoceratopsians, and with the possible oviraptorosaur remains, challenge the widespread assumption that these animals originated on the northern continents.
The holotype of Irritator challengeri Martill et al., 1996 from the Romualdo Member of the Santana Formation (Lower Cretaceous) in northeastern Brazil represents the most complete skull of a spinosaurid known to date. The now fully prepared specimen provides much new information on the cranial structure in these enigmatic predatory dinosaurs. The skull is remarkably narrow, especially in the region of the elongated snout. The maxillae are in broad contact along the midline, forming an extensive secondary bony palate. The maxillary teeth have straight or slightly recurved, conical crowns, with thin, fluted enamel and distinct but smooth carinae. As in Baryonyx walkeri, the anterior and ventral processes of the lacrimai meet at a more acute angle than in most non-avian theropod dinosaurs. The braincase is short anteroposteriorly but deep dorsoventrally, extending ventrally far below the occipital condyle. Irritator challengeri most closely resembles Spinosaurus aegyptiacus in the structure of its teeth, but more extensive comparisons between the two taxa are currently impossible due to the limited amount of cranial material known for the latter.
A newly discovered cervical vertebra from the Upper Cretaceous Lecho Formation of northwestern Argentina (Estancia El Brete) bears pneumatic foramina and epipophyses, and is assigned to the Theropoda. Although isolated, this specimen is significant because it is different from all described theropod cervical material from South America, most likely representing a new taxon. The El Brete specimen most closely resembles the cervical vertebrae of Chirostenotes, oviraptorids, and therizinosaurids. A cladistic analysis of cervical morphology groups the new specimen with those of the Laurasian oviraptorosaurs, suggesting the presence of this group of nonavian theropods in the Cretaceous of Gondwana.
The Tendaguru Formation of south-eastern Tan-zania has yielded the only diverse theropod fauna known from the Late Jurassic of Gondwana. Theropod remains have been recovered mainly from two members of the formation, the Middle and Upper Dinosaur members, which span from the Kimmeridgian to the latest Tithonian or earliest Creta-ceous. Here, four of the described taxa and additional isolated remains from this formation are reviewed and evaluated. Labrosaurus(?) stechowi Janensch, and Megalosaurus(?) ingens Janensch, are based on isolated teeth that do not show any unique derived characters, so these taxa are regarded as nomina dubia. Nevertheless, the teeth show character combi-nations indicative of ceratosaurid and carcharodontosaurid relationships, respectively. Ceratosaurus? roechlingi Janensch was based on associated fragmentary remains, which probably represent more than a single taxon. None of the type material shows diagnostic characters, so the species is a nomen dubium, and a middle caudal vertebra with possibly ceratosaurid affin-ities is designated as the lectotype. Allosaurus(?) tendgurensis Janensch is based on an isolated, poorly preserved basal tetanuran tibia, which cannot be diagnosed, so the species is also a nomen dubium. A new taxon, Veterupristisaurus milneri gen. et sp. nov., is based on diagnostic caudal vertebrae from the Middle Dinosaur Member. These elements show carchar-odontosaurid synapomorphies and, within this clade, share a unique derived character with the genus Acrocanthosaurus. In total, theropod material from the Tendaguru Formation indi-cates the presence of at least seven different species of thero-pods, including the ceratosaurian Elaphrosaurus bambergi Janensch, a probable ceratosaurid, a small abelisauroid, a probable abelisaurid, a small, noncoelurosaurian tetanuran, a possible megalosauroid and a carcharodontosaurid. Theropod faunas from the Middle and Upper Dinosaur members might differ slightly, but are similar in general taxonomic composi-tion. In broad systematic terms, the theropod fauna from Tendaguru shows greater similarities to Cretaceous Gondwa-nan theropod faunas than with contemporaneous fauna from the North American Morrison Formation, indicating that the complex evolutionary and biogeographical history of Creta-ceous Gondwanan theropod faunas can only be understood in the light of their Jurassic origins.
The first edition of this book was widely praised for its coverage and approach in describing and illustrating 14 well known fossil sites from around the world. The authors have now updated the text and added 6 new chapters with many new colour illustrations. Following a general introduction to fossil Lagerstätten, each chapter deals with a single fossil site and follows the same format: its evolutionary position and significance; its background sedimentology, stratigraphy and palaoenvironment; a description of the biota and palaeoecology, and a comparison with other similar Lagerstätten; and a list of relevant museums and suggestions for visiting the sites. This study of exceptionally well-preserved fossil sites from different periods in geological time provides a picture of the evolution of ecosystems down the ages. The book is beautifully illustrated throughout by over 450 colour photographs and diagrams, and is extensively referenced.Evolution of Fossil Ecosystems is of value to a wide range of students and professionals in palaeontology and related sciences, and to amateur enthusiasts.
We report the well preserved skeleton of a small theropod dinosaur, Nqwebasaurus thwazi, gen. et sp. nov., from the Lower Cretaceous Kirkwood Formation of South Africa. Nqwebasaurus has an elongate three-digit manus with a partially opposable first digit, a long and slender pes with a highly reduced metatarsal IV, and preserves gastroliths (stomach stones) in its abdominal region. As a basal coelurosaurian, Nqwebasaurus pushes back the Gondwanan record of this derived group of tetanuran theropods approximately 50 million years. This confirms that coelurosaurians were present on the Gondwana supercontinent well before its main phase of fragmentation and supports the hypothesis that this clade could have achieved a global distribution early in their evolution. Nqwebasaurus is one of the most complete and best preserved Cretaceous theropods described thus far from Africa.
Gondwanan dinosaurs, though less well-known than their Laurasian counterparts, are being discovered and described at an ever accelerating pace. Dinosaurs are known from every major Gondwanan landmass, including South America, Africa, Antarctica, Australia, India, Madagascar and New Zealand. Much of the Gondwana dinosaur literature includes speculation on vicariant and dispersal events relating to the fragmentation of Gondwana during the Jurassic and Cretaceous. These prolific biogeographic hypotheses are often inconclusive, speculative in nature, and untestable with the data at hand. To formulate well-supported biogeographic hypotheses, resolved dinosaur phylogenies and sound hypotheses of Earth history are necessary. Other factors, such as taphonomy, depositional setting, and missing taxonomic, temporal and geographic data, also contribute to understanding dinosaur faunal compositions. Additional phylogenetic information, a continuation of the current exploration and discovery, and knowledge of recent advances in tectonic plate reconstructions are paramount to developing a well-supported view of Gondwanan dinosaur biogeography.
The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footprints known in Brazil. In fact, most Brazilian specimens related to dinosaurs are composed of isolated teeth and vertebrae. Despite the increase of fieldwork during the last decade, there are still no dinosaur body-fossils of Jurassic age and the evidence of ornithischians in Brazil is very limited. Dinosaur faunas from this country are generally correlated with those from other parts of Gondwana throughout the Mesozoic. During the Late Triassic, there is a close correspondence to Argentina and other south-Pangaea areas. Mid-Cretaceous faunas of northeastern Brazil resemble those of coeval deposits of North Africa and Argentina. Southern hemisphere spinosaurids are restricted to Africa and Brazil, whereas abelisaurids are still unknown in the Early Cretaceous of the latter. Late Cretaceous dinosaur assemblages of south-central Brazil are endemic only to genus or, more conspicuously, to species level, sharing closely related taxa with Argentina, Madagascar, Indo-Pakistan and, to a lesser degree, continental Africa.
Dinosaur research is developing at very high rates around the world resulting in several new discoveries that are improving our understanding of this terrestrial reptilian clade. Except for the last couple years, the studies of Brazilian dinosaurs have not followed this expansive trend, despite the high potential of several dinosaur localities. So far there are only eight described taxa, four in the last year, representing theropod, sauropod, and one possible prosauropod taxa. Except for footprints, there are no records of ornithischian dinosaurs in the country what is at least partially explainable by the lack of continuous vertebrate fossil collecting program in the country. More funding is necessary to improve the research activities in this field.
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