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A review of coelophysoids (Dinosauria: Theropoda) from the Early Jurassic of Europe, with comments on the late history of the Coelophysoidea
Abstract
We review the available materials of Early Jurassic European theropods and confirm several as belonging to the clade Coelophysoidea. These include the holotypic partial skeleton of Liliensternus airelensis (France), fragmentary remains referred to as Sarcosaurus woodi and Sarcosaurus andrewsi (England), and a distal tibia (Scotland). Although incomplete, these specimens indicate that a wide size range of coelophysoids existed in Europe throughout the Early Jurassic, much as in North America. The record of coelophysoids from other continents is also reviewed, with particular attention to the later history of the clade. Coelophysoids apparently remained common worldwide into the Early Jurassic. They appear to have gone extinct by the end of the Early Jurassic, although the poor Middle Jurassic record may yet reveal late survivors of the group.
... This specimen was sporadically mentioned in the literature in subsequent years. Carrano and Sampson (2004) briefly reassessed NMS G.1994.10.1 and concluded that the specimen is a left tibia originally interpreted upside down. For example, the structure originally interpreted as the cnemial crest is the facet for reception of the ascending process of the astragalus. ...
... For example, the structure originally interpreted as the cnemial crest is the facet for reception of the ascending process of the astragalus. Carrano and Sampson (2004) did not provide a redescription and noted similarities to Coelophysis, 'Syntarsus' and Liliensternus, identifying it as an indeterminate member of Coelophysoidea (a group that at that time included several averostran-line neotheropods; e.g. Dilophosaurus wetherilli, Sarcosaurus woodi). ...
... We agree with Carrano and Sampson (2004) in the reinterpretation of NMS G.1994.10.1 as a left tibia lacking its proximal region (contra Benton et al. 1995). Thus, the cnemial crest, posterior hemicondyles of the proximal end and the fibular crest are not preserved. ...
The broadest diversification of early predatory dinosaurs is represented by the ‘coelophysoid-grade’ neotheropods, but their Hettangian–Sinemurian (ca. 191–201 Ma) record is scarce worldwide. More information is needed to shed light on the evolution of this dinosaur group after the end-Triassic mass extinction (ca. 201 Ma). Here we revisit the anatomy and phylogeny of one of these earliest Jurassic neotheropod specimens, an isolated partial tibia from the lower Sinemurian of the Isle of Skye (Scotland) that was previously identified as probably closely related to Liliensternus liliensterni and coelophysids. However, we found that the Skye specimen is positioned in the branch leading to Averostra (Ceratosauria + Tetanurae), in a polytomy with Sarcosaurus woodi from the late Hettangian–lower Sinemurian of central England and a clade composed of Tachiraptor admirabilis and Averostra. The morphology of the Skye specimen is congruent with that of referred specimens of Sarcosaurus woodi , but because it probably represents a skeletally immature specimen, we assign it to cf. Sarcosaurus woodi . The Skye specimen increases the number of averostran-line neotheropod specimens recorded in the Lower Jurassic of Europe and current evidence indicates that these forms, and not coelophysoids, were relatively common in this part of the world at that time.
Thematic collection: This article is part of the Palaeontology of Scotland collection available at: https://www.lyellcollection.org/topic/collections/palaeontology-of-scotland
Supplementary material: https://doi.org/10.6084/m9.figshare.c.6863016
... The Lower Jurassic rocks of central England have yielded three neotheropod specimens that, although rather incomplete, were the best records of the group from this time interval in the UK (von Huene, 1932;Carrano & Sampson, 2004), prior to the recent discovery of Dracoraptor hanigani Martill et al., 2016. Andrews (1921 described a fragmentary theropod specimen collected from the lower part of the Lias Group (bucklandi zone, lower Sinemurian) of Barrow upon Soar in Leicestershire (Fig. 1). ...
... Andrews (1921) made this specimen the type species of a new genus and species, Sarcosaurus woodi Andrews, 1921. The taxon has received little subsequent attention, but was reviewed and redescribed by Carrano & Sampson (2004), who referred it to Coelophysoidea. They argued that Sarcosaurus woodi was likely to be distinct from all other known taxa based on its provenance, but considered it as a nomen dubium because they were unable to diagnose the species based on either autapomorphies or a distinct combination of character states. ...
... Woodward (1908) described NHMUK PV R3542, a right tibia, from the late Hettangian angulata zone. von Huene (1932) subsequently made this specimen the type of the new species, Sarcosaurus andrewsi Huene, 1932, which was also considered a nomen dubium by Carrano & Sampson (2004). von Huene (1932) also described a fragmentary partial skeleton, WARMS G667-690 (Fig. 2), which he referred to Sarcosaurus woodi. ...
Neotheropoda represents the main evolutionary radiation of predatory dinosaurs and its oldest records come from Upper Triassic rocks (c. 219 Mya). The Early Jurassic record of Neotheropoda is taxonomically richer and geographically more widespread than that of the Late Triassic. The Lower Jurassic (upper Hettangian–lower Sinemurian) rocks of central England have yielded three neotheropod specimens that have been assigned to two species within the genus Sarcosaurus, S. woodi (type species) and S. andrewsi. These species have received little attention in discussions of the early evolution of Neotheropoda and recently have been considered as nomina dubia. Here, we provide a detailed redescription of one of these specimens (WARMS G667–690) and reassess the taxonomy and phylogenetic relationships of the genus Sarcosaurus. We propose that the three neotheropod specimens from the Early Jurassic of central England represent a single valid species, S. woodi. The second species of the genus, ‘S. andrewsi’, is a subjective junior synonym of the former. A quantitative phylogenetic analysis of early theropods recovered S. woodi as one of the closest sister-taxa to Averostra and provides new information on the sequence of character state transformations in the lead up to the phylogenetic split between Ceratosauria and Tetanurae.
... Subsequent studies reassessed the affinities of the specimens and concluded instead that these specimens represented a theropod or several theropods, and not an early-branching ornithischian as originally thought (e.g., Newman, 1968). Carrano and Sampson (2004), who evaluated several early theropods in their study, concluded idented that articulated knee joint at least probably belonged to a basal, indeterminate tetanurine theropod. Naish and Martill (2007) similarly referred all the specimens to Tetanurae in their comprehensive study of British non-avian dinosaur taxa. ...
... Skeletal remains of Early Jurassic theropods being extremely sparse in Europe (Larsonneur and Lapparent, 1966;Carrano and Sampson, 2004;Delsate and Ezcurra, 2014;Dal Sasso et al., 2018) and throughout the world (Weishampel et al., 2004;Smith et al., 2007;Xing et al., 2013), tracksites are important tools to reconstruct dinosaurs from this time period and their palaeoecosystems. Since many Hettangian-Sinemurian archosaur trackways were discovered in the Causses Basin (southern France), the tracksites from this area became capital for the study of Early Jurassic ichnofaunas (Ellenberger, 1988;Demathieu, 1990;Sciau, 1992, 1999;Sciau, 1998Sciau, , 2003Sciau, , 2019Demathieu et al., 2002;Gand et al., 2007;Moreau, 2011;Moreau et al., 2012aMoreau et al., , 2014Moreau et al., , 2019aMoreau et al., , 2021a. ...
During the 20th century, the first dinosaur tracks of the Causses Basin were identified at Saint-Laurent-de-Trèves, in the Parc National des Cévennes (southern France). A recent excavation reveals a new theropod tracksite in the Hettangian deposits from Le Mazel, 2 km from the historical tracksite at Saint-Laurent-de-Trèves. The tracks are here described combining a biometric approach and 3D imaging photogrammetry. The main track-bearing surface bears 64 in situ tridactyl footprints preserved as concave epireliefs. Two morphotypes were identified, a “Grallatorid” morphotype and a “Kayentapus” morphotype. Footprints belonging to the first morphotype are closely similar to Grallator lescurei, Grallator minusculus, and Grallator sauclierensis. This study shows the difficulty to distinguish quite similar tridactyl tracks from an ichnotaxonomic point of view and highlights the importance of detailed biometric comparisons. Tracks are preserved in a brown to yellowish dolomudstone showing abundant cryptalgal laminites and mud cracks. These deposits were accrued in shallow environments such as intertidal and supratidal zones of a tidal flat.
... The Lockatong Formation is of late Carnian age (Late Triassic), and is approximately contemporaneous to the Cow Branch Formation from which the better known Tanytrachelos ahynis is known (Colbert & Olsen, 2001). The only known specimen was originally described by Bock (1945) and considered to be closely related to Podokesaurus holyokensis, a poorly known early theropod dinosaur (Carrano & Sampson, 2004). The holotype and only known specimen represents a disarticulated skeleton preserving several vertebrae, ribs, parts of the pectoral girdle, and limb elements. ...
The historical clade “Protorosauria” represents an important group of archosauromorph reptiles that had a wide geographic distribution between the Late Permian and Late Triassic. “Protorosaurs” are characterized by their long necks, which are epitomized in the genus Tanystropheus and in Dinocephalosaurus orientalis . Recent phylogenetic analyses have indicated that “Protorosauria” is a polyphyletic clade, but the exact relationships of the various “protorosaur” taxa within the archosauromorph lineage is currently uncertain. Several taxa, although represented by relatively complete material, have previously not been assessed phylogenetically. We present a new phylogenetic hypothesis that comprises a wide range of archosauromorphs, including the most exhaustive sample of “protorosaurs” to date and several “protorosaur” taxa from the eastern Tethys margin that have not been included in any previous analysis. The polyphyly of “Protorosauria” is confirmed and therefore we suggest the usage of this term should be abandoned. Tanystropheidae is recovered as a monophyletic group and the Chinese taxa Dinocephalosaurus orientalis and Pectodens zhenyuensis form a new archosauromorph clade, Dinocephalosauridae, which is closely related to Tanystropheidae. The well-known crocopod and former “protorosaur” Prolacerta broomi is considerably less closely related to Archosauriformes than was previously considered.
... Body fossils of earliest Jurassic theropod were ascribed to Coelophysidea and Ceratosausoria and reported in Antarctica, China, South Africa and USA ( Weishampel et al. 2004;Smith et al. 2007;Xing et al. 2013). In Europe, rare theropod body fossils were reported in Hettangian deposits of England, France and Luxembourg (Larsonneur & Lapparent 1966;Carrano & Sampson 2004;Delsate & Ezcurra 2014). In France, there is a unique occurrence of theropod bones in the Moon-Airel Formation (Normandie; Larsonneur & Lapparent 1966). ...
A new vertebrate ichnological assemblage is described from the Hettangian Dolomitic Formation of the Causses Basin, at Le Serre (Lozère, southern France). We report tracks that complement the poor fossil record of lowermost Jurassic crocodylomorphs in Europe. Tetradactyl pes and pentadactyl manus imprints form a unique trackway. Traces are ascribed to Batrachopus isp. and they represent the third occurrence of this ichnogenus in European Hettangian geological formations. This is the first report of Batrachopus in Hettangian deposits of the Causses Basin. The tracks share some similarities with Batrachopus deweyi previously described from the Sinemurian of the Causses Basin. Crocodylomorph tracks co-occur with tridactyl dinosaur traces assigned to Dilophosauripus williamsi and Grallator isp. The sedimentology and palaeoichnology of the tracksite indicate that the depositional environment was a tidal to supratidal flat marsh that was emerged periodically. The ichnological assemblage from Le Serre and a synthesis of ichnotaxa co-occurring with Batrachopus in the European lowermost Jurassic tracksites confirm that crocodylomorphs living in marginal-littoral palaeoenvironments were part of theropod-dominated faunas, together with ornithopods but apparently without sauropods.
... Early Jurassic saurischians from Gond- wana are also indicative of a global Pan- gean dinosaur fauna at that time (see also Smith et al. 2007b). In theropods, coe- lophysoids are found on all major land- masses from which theropods have been reported (Raath 1969, Rowe 1989, Carrano and Sampson 2004, Irmis 2004, Tykoski 2005, with the exception of An- tarctica. Furthermore, the recently re- cognized dilophosaur clade (Smith et al. 2007a, b) also shows a global distribu- tion, with representatives known from North America, China, South Africa, and Antarctica. ...
We report the first Hettangian theropod tracksite (~200 Ma) yielding a rich accumulation of plant remains from the Bleymard Strait (southern France). It constitutes an excellent opportunity to reconstruct lowermost Jurassic ecosystems hosting dinosaurs and which are still poorly documented in this area. Two morphotypes of tridactyl tracks are distinguished. They share similarities with Grallator and Kayentapus. Plant-bearing beds yield abundant leafy axes (Pagiophyllum peregrinum), male cones (Classostrobus sp.), wood (Brachyoxylon sp.) and pollen of conifers (Classopollis classoides). Sedimentological, petrological and mineralogical analyses demonstrated that, in the Dolomitic Formation from Bleymard, the palaeoenvironment progressively evolved from (1) a shoreface to a foreshore domain; to (2) a shallow environment that is restricted or occasionally open to the sea; then to (3) an intertidal to supratidal zone. The Hettangian theropod ecosystem of the Bleymard Strait was composed of tidal flats that were periodically emerged and bordered paralic environments inhabited by a littoral conifer-dominated forest in which Cheirolepidiaceae were the main component. The paucity of the palaeobotanical assemblage, as well as the xerophytic characteristics of Pagiophyllum, show that flora from Bleymard was adapted to withstand intense sunlight and coastal environments exposed to desiccant conditions coupled with salty sea spray, and dry conditions. These features are those of a conifer-dominated flora under a tropical to subtropical climate. The flora as well as the clay mineral analyses suggest contrasting seasons (cyclically dry then humid). This study supports that theropods were abundant and particularly adapted to this type of littoral environment bordering Cheirolepidiaceae-dominated forests.
A recent excavation yielded 118 large tridactyl footprints in the Lower Jurassic Dolomitic Formation of the Causses Basin, at Mongisty in southern France. Most of the tracks are ascribed to Eubrontes giganteus Hitchcock, 1845. They are preserved on a surface of 53 m ² and form parallel rows with a preferential orientation towards the north. Such an abundance and density of E. giganteus is observed for the first time in the Early Jurassic from the Causses Basin. Sedimentological and ichnotaphonomical analyses show that the footprints were made at different time intervals, thus excluding the passage of a large group. In contrast to all other tracksites from the Dolomitic Formation, where tracks are preserved in fine-grained sediments corresponding to low-energy depositional palaeoenvironments, the tracks from Mongisty are preserved in coarse-grained sediment which is a matrix- to clast-supported breccia. Clasts consist of angular to sub-rounded, millimetric to centimetric-scale (up to 2 cm), poorly sorted, randomly oriented, homogeneous dolostone intraclasts floating in a dolomudstone matrix. Sedimentological analysis shows that the depositional environments of Mongisty varied from subtidal to intertidal/supratidal settings in a large and protected flat marsh. The lithology of the track-bearing surfaces indicates that the mudflat of the Causses Basin was sporadically affected by large mud flows that reworked and redeposited mudstone intraclasts coming from the erosion of upstream, dry and partially lithified mud beds. Throughout the world, this type of preservation of dinosaur tracks in tidal matrix- to clast-supported breccias remains rare.
Terrestrial reptile remains are rare in Early Jurassic deposits from the UK but include important records of early dinosaurs and pterosaurs. Here we report an isolated limb bone from the Charmouth Mudstone Formation (upper Sinemurian) of Charmouth, Dorset that was previously misidentified as a referred specimen of the pterosaur Dimorphodon macronyx. Comparisons with other Early Jurassic tetrapods indicate that this element is the fibula of a neotheropod dinosaur, representing one of only a handful of theropod remains from the Lias Group. Although the material is limited the fibula is distinct from other penecontemporaneous European theropods and might represent a new – though currently undiagnosable – taxon. This, alongside other isolated discoveries, indicates that there might have been a higher diversity of theropod taxa in the Early Jurassic of Europe than is generally appreciated.
Femoral osteology and soft tissues evolved in a stepwise pattern in archosauromorph reptiles on the line to crown group birds. Crocodylia retains most ancestral archosaurian traits, whereas Dinosauromorpha (including birds) acquired many more derived traits. The complex sequence of changes included major shifts of several thigh muscle insertions. Medial rotation of the proximal femur (e.g. the femoral head) in archosaurs moved the greater trochanter laterally, bringing along the insertion of M. pubo-ischio-femoralis externus. Within Dinosauromorpha, the lesser trochanter moved proximally away from the trochanteric shelf. Presumably the lesser trochanter indicates the insertion of M. iliotrochantericus caudalis whereas the trochanteric shelf indicates the insertion of M. iliofemoralis externus. An accessory trochanter at the base of the lesser trochanter marks the insertion of M. pubo-ischio-femoralis internus 2 in tetanuran theropods. I propose hypotheses for the homologies of several intermuscular lines and other features on the femoral shaft. On the line to Neornithes, most changes of femoral morphology predated Aves and the origin of flight; few femoral features are unique to birds. Overall, the pattern of morphological evolution is consistent with stepwise functional evolution of the hindlimb within Dinosauromorpha on the line to Neornithes. The clade Ornithurae evolved the last few hindlimb apomorphies that characterize extant birds, in conjunction with more flexed hip and knee joints.
Synopsis
A partial right tibia of a carnivorous dinosaur is reported from the Lower Jurassic Broadford Beds Formation of southern Strath, Skye. The bone consists of the proximal end and shaft of a tibia, and this shows characteristic features of the ceratosaur theropods, a group of medium-sized predatory dinosaurs that were widespread during the Early Jurassic. This tibia, and a partial sauropod tibia from the Middle Jurassic of Skye, represent the first clear records of dinosaur body fossils from Scotland.
We describe the osteology of the new small theropod dinosaur Masiakasaurus knopfleri, from the Late Cretaceous Maevarano Formation of northwestern Madagascar. Approximately 40% of the skeleton is known, including parts of the jaws, axial column, forelimb, pelvic girdle, and hind limb. The jaws of Masiakasaurus are remarkably derived, bearing a heterodont, procumbent dentition that is unknown elsewhere among dinosaurs. The vertebrae are similar to those of abelisauroids in the reduction of the neural spine, lack of pleurocoelous fossae on the centrum, and extensively pneumatized neural arch. The limb skeleton is relatively gracile and bears numerous abelisauroid synapo-morphies, including a rounded humeral head, peg-and-socket iliac-pubic articulation, prominent femoral medial epi-condyle, expanded tibial cnemial crest, and double-grooved pedal unguals. The femora and tibiae show evidence of dimorphism. More specific features shared between Masiakasaurus, the Argentine Noasaurus, and the Indian Laevi-suchus suggest that these taxa form a clade (Noasauridae) within Abelisauroidea. This is supported by a cladistic phylogenetic analysis of 158 characters and 23 theropod taxa. Additionally, Ceratosauria is rendered paraphyletic in favor of a sister-taxon relationship between Neoceratosauria and Tetanurae that is exclusive of Coelophysoidea. The unique dental and jaw specializations of Masiakasaurus suggest deviation from the typical theropod diet. Finally, the distribution of noasaurids further supports a shared biogeographic history between South America, Madagascar, and India into the Late Cretaceous.
Coelophysis length measurements for humerus, femur, tibia, MTIII