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Most parsimonious tree with stratigraphic ranges of Permian and Triassic diapsids included in this study. Black bars represent known temporal ranges and bars with cross hatching are missing portions of lineages derived from minimum time of divergence of clades.
Source publication
Restudy of the unique diapsid reptile Mesosuchus browni Watson, from the Cynognathus Assemblage Zone (late Early Triassic to early Middle Triassic) of the Burgersdorp Formation (Tarkastad Subgroup; Beaufort Group) of South Africa, confirms that it is the most plesiomorphic known member of the Rhynchosauria. A new phylogenetic analysis of basal taxa...
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Citations
... Archosaurs and their closest relatives such as Proterosuchidae and Euparkeriidae are grouped together as Archosauriformes. In addition, various other, mainly Triassic diapsid reptiles that are more closely related to archosauriforms than to lepidosauromorphs have been united with Archosauriformes as Archosauromorpha (Benton, 1985;Dilkes, 1998;Ezcurra, 2016;Sues, 2019). Following the end-Permian extinction event, archosauromorph reptiles rapidly diversified and dispersed across Pangea during the Early and early Middle Triassic (Ezcurra, 2016;Ezcurra & Butler, 2018;Foth et al., 2016). ...
... Most archosauriforms (besides Proterosuchus) have a second sacral rib that is not bifurcated (Nesbitt, 2011). In most early-diverging archosauromorphs, the posterior processes of the sacral ribs exhibit a sharply pointed morphology (Dilkes, 1998;Pritchard et al., 2015). ...
... 0), different from the low neural spines of tanystropheids, P. broomi, among other archosauromorphs; posterior process of sacral rib sharply pointed (374 ! 1), a feature also present in some tanystropheids (Macrocnemus bassanii and Langobardisaurus pandolfii) and Rhynchosaurus articeps (Dilkes, 1998;Ezcurra, 2014;Gower et al., 2014;Pritchard et al., 2015). It is also important to mention, however, that some recent work indicates that rhynchosaurs and allokotosaurs may be more closely related to Archosauriformes than P. broomi. ...
Teyujagua paradoxa is a remarkable early archosauromorph from the Lower Triassic Sanga do Cabral Formation, Brazil. The species was originally described from an almost complete skull and a few associated cervical vertebrae, and no further postcranial elements were known at that time. Additional fieldwork in the Sanga do Cabral Formation, however, was successful in recovering a fairly complete postcranial skeleton attributable to the holotype. Here, we describe this new postcranial material, which is composed of cervical, dorsal, sacral and caudal vertebrae, limbs, pectoral and pelvic girdles, ribs, and gastralia. The description of its postcranial skeleton makes T . paradoxa one of the best‐known early‐diverging archosauromorphs. The cladistic analysis performed after the scoring of postcranial data recovered T . paradoxa in the same position initially described, close to the node that defines the Archosauriformes. Teyujagua paradoxa shares morphological features with representatives of early‐diverging archosauromorphs and archosauriforms, with certain traits demonstrating a mosaic of plesiomorphic and apomorphic character states. We also performed partitioned morphospace and disparity analysis to elucidate the morphological disparity and evolutionary patterns among archosauromorphs. Teyujagua paradoxa occupies a notable position, suggesting an intermediate morphology between early archosauromorphs and proterosuchids. Disparity estimates highlighted Pseudosuchia and Avemetatarsalia as having the highest median disparity, reflecting their diverse cranial and postcranial morphologies, respectively. These findings offer valuable insights into archosauromorph macroevolution and adaptation.
... Curtis et al., 2011;Evans, 2003;Evans & Jones, 2010;Jones, 2008;Moazen et al., 2009). Moreover, revisions of several Permo-Triassic taxa over the last few decades suggest that the last common ancestor of Archosauromorpha and Lepidosauromorpha also lacked a lower temporal bar (Curtis et al., 2011;Dilkes, 1998;Moazen et al., 2009;M€ uller, 2003). Under that hypothesis, a complete lower bar arose independently in several lineages (rhynchosaurs, archosauriforms, rhynchocephalians). ...
... Archosauromorpha von Huene, 1946 [81] sensu Dilkes, 1998 [82] Rhynchosauridae Cope, 1871 [83] sensu Dilkes, 1998 [82] Hyperodapedontinae (Chatterjee, 1969 [64] nom. trans. ...
... Archosauromorpha von Huene, 1946 [81] sensu Dilkes, 1998 [82] Rhynchosauridae Cope, 1871 [83] sensu Dilkes, 1998 [82] Hyperodapedontinae (Chatterjee, 1969 [64] nom. trans. ...
... The cross-sectional shape of this groove becomes thinner and shallower towards its anterior termination. The presence of a longitudinal groove and of a convex occlusal surface are both synapomorphic of Rhynchosauridae [82,86]. This longitudinal groove extends well into the anterior half of the maxilla, as in most rhynchosaurids and unlike Stenaulorhynchus stockleyi and Brasinorhynchus mariantensis [12]. ...
New discoveries in the lower Popo Agie Formation (lower carbonate unit) of central Wyoming necessitated a reevaluation of USNM 494329 from the same unit, the only known hyperodapedontine rhynchosaur in western North America. Well known from Gondwanan deposits, hyperodapedontines appear to be restricted to the Carnian age (Late Triassic), with the exception of Teyumbaita in the earliest Norian age (Late Triassic) of Brazil. Initially assigned to c.f. ‘Hyperodapedon’ sanjuanensis, our phylogenetic analyses reject this hypothesis, in support of a sister relationship between USNM 494329 (Beesiiwo cooowuse, gen. et. sp. nov.) and Oryctorhynchus bairdi forming an early-diverging clade that is only distantly related to ‘H.’ sanjuanensis. Five additional specimens recovered from the lower Popo Agie are described. Three are referred to B. cooowuse, and another two are placed closer to Hyperodapedon and the remainder of Hyperodapedontinae. Our analysis demonstrates potential temporal distinction between a grade of earliest-diverging hyperodapedontines (including all Wyoming taxa) and a exclusively Late Carnian, Southern Pangaean hyperodapedontine clade (including ‘H.’ sanjuanensis). We consider the lower Popo Agie Formation to represent the first nonmarine Late Triassic unit of Western North America that can be confidently restricted to the Carnian age.
... Trilophosaurid stem-archosaurs were long known only from the Late Triassic of the United States and Great Britain. However, recent time-calibrated phylogenies of Archosauromorpha have predicted a much longer temporal range of this clade, extending back into the Permian [6,22,42]. The isolated tooth crown from the Economy Member of the Wolfville Formation in Nova Scotia, Canada provided the first evidence of a Middle Triassic trilophosaurid [33]. ...
We report the first trilophosaurid stem-archosaur from Central Europe, Rutiotomodon tytthos gen. et sp. nov., from the Middle Triassic (Ladinian) Erfurt Formation of Baden-Württemberg (Germany). It is currently known from two jaw fragments with distinctive teeth. The labiolingually wide but mesiodistally narrow maxillary and dentary teeth each have a large labial cusp from which an occlusal ridge extends lingually to a small lingual cusp. A mesial and a distal cingulum extend between the labial and lingual cusps. The mesial and distal faces of the labial cusp each bear three prominent, lingually curved apicobasal ridges (arrises). A referred partial dentary has an edentulous, expanded symphysis similar to the mandibular ‘beak' in Trilophosaurus buettneri. A review of Coelodontognathus ricovi, from the Lower Triassic (Olenekian) of southwestern Russia, supports its referral to Trilophosauridae rather than Procolophonidae. Based on this reassessment and the new material from the Middle Triassic, the temporal range of trilophosaurids now spans nearly the entire Triassic Period, from the Olenekian to the Rhaetian. Trilophosaurids present craniodental features that indicate omnivory or herbivory with limited oral food processing. They were more diverse in terms of dental structure (and presumably diet) than previously assumed.
... The ventral margin of the atlantal centrum is rounded, suggesting that it FIGURE 1. Coelurosauravus elivensis Piveteau, 1926 (Madagascar, is sub-circular in outline. The bone was not fused with the axial intercentrum, as in some early amniotes Acerosodontosaurus, Hovasaurus and most early archosauromorphs (Gow, 1972(Gow, , 1975Currie, 1980Currie, , 1981aSumida et al., 1992;Dilkes, 1998;deBraga, 2003;Campione and Reisz, 2011;Miedema et al., 2020) but unlike some allokotosaurian archosauromorphs and most lepidosauromorphs (Hoffstetter and Gasc, 1969;Nesbitt et al., 2015;O'Brien et al., 2018). ...
... As is visible in medial view on the left side of MNHN.F.MAP327a, the scapular blade is reinforced anteriorly by a low scapular torus (sensu Pawley and Warren, 2006), and the blade becomes gradually thinner dorsally in longitudinal direction (Fig. 11). Its anterior margin is roughly vertical in contrast to the strongly convex anterodorsal margin of the scapular blade of araeoscelidians (Vaughn, 1955;Reisz, 1981), and the concave one of drepanosauromorphs (Renesto et al., 2010;Castiello et al., 2016) and several archosauromorphs (Dilkes, 1998;Spielmann et al., 2008;Nesbitt et al., 2015). The dorsal surface of the blade forms a rugose margin suggesting the presence of a cartilaginous suprascapula. ...
The postcranial skeleton of the gliding neodiapsid reptile Coelurosauravus elivensis (Lower Sakamena Formation, ?upper Permian, southwestern Madagascar) is re-described in detail based on all previously referred specimens. The exquisite preservation of the material provides three-dimensional details of the individual bones, which are missing in the Laurasian weigeltisaurid material. A new skeletal reconstruction of C. elivensis is proposed including the first reconstruction of a weigeltisaurid reptile in lateral view. The re-examination of the material highlights interspecific differences in the postcranium of weigeltisaurids, in particular in the trunk and patagial spars. These animals have long been considered as arboreal and gliding reptiles. However, new information on the postcranium of C. elivensis reveals strong similarities with both extant and extinct quadrupeds specialized for a clinging arboreal lifestyle. Additionally, the presence of an additional phalanx in the fifth digit of the manus is now attested for all weigeltisaurids where this region is preserved. We suggest that this morphology could have allowed weigeltisaurids to grasp their patagium as observed in the extant gliding agamid Draco. Weigeltisaurids are thus the earliest known gliding vertebrates and some of the first tetrapods with an obligatory arboreal lifestyle, but also represent the only known vertebrates with a hyperphalangy aligned with a gliding apparatus.
... Our analysis employs the araeoscelid diapsid Petrolacosaurus kansensis as an outgroup, as in many prior studies of diapsid interrelationships (e.g., Dilkes, 1998;Ezcurra, 2016). We note that numerous recent phylogenetic analyses recover some non-diapsid taxa as more closely related to Neodiapsida than Araeoscelida. ...
... However, this margin is in contact with a medial process of a discrete postorbital in all of these species. The posterior margin of the postfrontal is strongly posteromedially inclined in Avicranium renestoi (AMNH FARB 30834; Pritchard & Nesbitt, 2017), Youngina capensis (BP/1 3859, SAM-PK 7578), Claudiosaurus germaini (Carroll, 1981), Mesosuchus browni (SAM-PK 6536; Dilkes, 1998), and Trilophosaurus buettneri (TMM 31025-140;Gregory, 1945). ...
... In many ways, the proportionally elongate cervical centra with relatively short pedicles in weigeltisaurids and araeoscelids (following Carroll, 1988) resemble those of many early archosauromorphs, such as Protorosaurus speneri (Gottmann-Quesada & Sander, 2009), Trilophosaurus buettneri (TMM 31025-140; Gregory, 1945), and Prolacerta broomi (BP/1 2675; Gow, 1975). Although these archosauromorph taxa with relatively long cervical vertebrae were long considered members of a grouping variously dubbed Protorosauria or Prolacertiformes (Wild, 1973;Benton, 1985;Evans, 1987Evans, , 1988, more recent analyses indicate that these reptiles represent a paraphyletic grade relative to Archosauriformes (Dilkes, 1998;Pritchard et al., 2015;Ezcurra, 2016;Pritchard & Nesbitt, 2017). ...
Background
Weigeltisauridae is a clade of small-bodied diapsids characterized by a horned cranial frill, slender trunk and limbs, and a patagium supported by elongated bony rods. Partial skeletons and fragments are definitively known only from upper Permian (Lopingian) rocks in England, Germany, Madagascar and Russia. Despite these discoveries, there have been few detailed descriptions of weigeltisaurid skeletons, and the homologies of many skeletal elements—especially the rods supporting the patagium—remain the subject of controversy.
Materials & Methods
Here, we provide a detailed description of a nearly complete skeleton of Weigeltisaurus jaekeli from the upper Permian (Lopingian: Wuchiapingian) Kupferschiefer of Lower Saxony, Germany. Briefly addressed by past authors, the skeleton preserves a nearly complete skull, postcranial axial skeleton, appendicular skeleton, and patagial supports. Through comparisons with extant and fossil diapsids, we examine the hypotheses for the homologies of the patagial rods. To examine the phylogenetic position of Weigeltisauridae and characterize the morphology of the clade, we integrate the material and other weigeltisaurids into a parsimony-based phylogenetic analysis focused on Permo-Triassic non-saurian Diapsida and early Sauria (61 taxa, 339 characters).
Results
We recognize a number of intriguing anatomical features in the weigeltisaurid skeleton described here, including hollow horns on the post-temporal arch, lanceolate teeth in the posterior portion of the maxilla, the absence of a bony arch connecting the postorbital and squamosal bones, elongate and slender phalanges that resemble those of extant arboreal squamates, and patagial rods that are positioned superficial to the lateral one third of the gastral basket. Our phylogenetic study recovers a monophyletic Weigeltisauridae including Coelurosauravus elivensis , Weigeltisaurus jaekeli , and Rautiania spp. The clade is recovered as the sister taxon to Drepanosauromorpha outside of Sauria (=Lepidosauria + Archosauria).
Conclusions
Our anatomical observations and phylogenetic analysis show variety of plesiomorphic diapsid characters and apomorphies of Weigeltisauridae in the specimen described here. We corroborate the hypothesis that the patagial ossifications are dermal bones unrelated to the axial skeleton. The gliding apparatus of weigeltisaurids was constructed from dermal elements unknown in other known gliding diapsids. SMNK-PAL 2882 and other weigeltisaurid specimens highlight the high morphological disparity of Paleozoic diapsids already prior to their radiation in the early Mesozoic.
... Pritchard et al. (2015). (C) Rieppel, Fraser & Nosotti (2003), which represents a compilation of the matrices of Benton & Allen (1997), Jalil (1997), and Dilkes (1998). conclude that Prolacerta, together with Macrocnemus and Tanystropheus, was not part of the lepidosaurian lineage, but instead was archosaurian in many of its features. ...
... In the same year, the description of a new "protorosaur", Jesairosaurus lehmani, was accompanied by an analysis including ten "protorosaurs" and eight outgroup taxa, employing 71 characters (Jalil, 1997; the initial analysis also included Trachelosaurus, Prolacertoides, Malutinisuchus, and Kadimakara, but these poorly known taxa were excluded from the final analysis, as the inclusion of these taxa left "protorosaurs" interrelationships unresolved). Another study addressing early archosauromorph phylogeny also included several "protorosaurs" (Dilkes, 1998. This new species was previously considered to represent the adult stage of Tanystropheus longobardicus (Wild, 1973), but long bone histology revealed that the small-sized specimens of Tanystropheus longobardicus were skeletally mature, thus representing a separate species from the newly recognized Tanystropheus hydroides. ...
... Tanystropheidae was recovered as a monophyletic clade and consisted of Macrocnemus, Amotosaurus, Tanystropheus, Langobardisaurus, Tanytrachelos, and the new Hayden Quarry material that was presented therein. The character list consisted of 200 characters, including novel characters and characters derived from many previous analyses (Benton, 1985;Benton & Allen, 1997;Conrad, 2008;DeBraga & Rieppel, 1997;Dilkes, 1998;Gauthier, 1984;Gauthier, Estes & De Queiroz, 1988;Gauthier, Kluge & Rowe, 1988;Hutchinson, Skinner & Lee, 2012;Jalil, 1997;Merck, 1997;Modesto & Sues, 2004;Müller, 2004;Nesbitt, 2011;Rieppel, 1994). Ezcurra (2016) presented a very extensive analysis of early archosauromorph interrelationships that used 600 characters to analyze 96 taxa. ...
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.
... The anterior tip and medial side of the anterior region of the dentary are damaged. The anterior end is strongly dorsally curved and tapers anteriorly, as occurs in other rhynchosaurids (Benton 1990;Dilkes 1998). The ventral margin of the anterior end possesses a distinct dorsal inflexion that would have been at level of the anterior end of the mandibular symphysis. ...
... Scale bar: 1 cm. Dilkes 1998). The dorsal surface of the bone is strongly transversely convex and there is no evidence of teeth. ...
... These roots are deeply implanted and in direct contact with the bone, indicating a dental attachment via ankylosis, as is the case in other rhynchosaurs (e.g. Benton 1984;Dilkes 1998). ...
Rhynchosaurs were quadrupedal, bulky herbivorous archosauromorph diapsids with a highly specialized dental apparatus. This group is restricted to the Triassic Period and became extremely abundant worldwide during the late Carnian, numerically dominating some of the first dinosaur-bearing assemblages. Despite their high abundance in upper Carnian beds of South America, rhynchosaurs are restricted to a handful of specimens in the latest Ladinian–early Carnian tetrapod assemblages of this continent. Here, we improve the record of one of the oldest rhynchosaur assemblages of South America with the detailed description of all the rhynchosaur specimens currently known from the Tarjadia Assemblage Zone (AZ) (late Ladinian–?earliest Carnian) of the Chañares Formation (Ischigualasto-Villa Unión Basin, La Rioja Province). Most of these specimens were only preliminarily reported before, and as part of this revision we name the new taxon Elorhynchus carrolli gen. et sp. nov. based on one of these specimens, which represents the first new taxon for the Chañares Formation in 22 years. Elorhynchus carrolli and three more rhynchosaur specimens from the Chañares Formation are identified as stenaulorhynchine rhynchosaurs based on the presence of a crowded field of numerous lingual teeth in the dentary and the presence of small occlusal teeth in the maxillary tooth plate. Although their morphology is congruent, we did not refer the other stenaulorhynchine specimens to Elorhynchus carrolli because they lack diagnostic overlapping character states between them. Nevertheless, there is no current evidence for the presence of more than one rhynchosaur species in the Chañares Formation. The description of Elorhynchus carrolli and the other stenaulorhynchines from the Chañares Formation reinforces biostratigraphical links with the Dinodontosaurus AZ (Santa Maria Supersequence) of southern Brazil and the Lifua Member of the Manda Beds of Tanzania.
... Instead, there is a small posterior extension on the medial end of the bone, which does not bear an articulation surface for the nasal to form an internarial bar. The prenarial process of Tanystropheus longobardicus and Macrocnemus spp. is also incipient, and has been reduced completely in rhynchosaurs, Teyujagua paradoxa, and the allokotosaurs Azendohsaurus madagaskarensis, Pamelaria dolichotrachela, and Shringasaurus indicus among early archosauromorphs (Dilkes, 1998;Flynn et al., 2010;Miedema et al., 2020;Nosotti, 2007;Pinheiro, Simão-Oliveira & Butler, 2019;Sengupta, Ezcurra & Bandyopadhyay, 2017). In contrast, the prenarial process is well-established and elongate in Protorosaurus speneri, Prolacerta broomi, Dinocephalosaurus orientalis, and Pectodens zhenyuensis (Gottmann-Quesada & Sander, 2009;Li et al., 2017;Modesto & Sues, 2004;Rieppel, Li & Fraser, 2008). ...
... No clear supratemporal fossae are present, and the main body of the parietals is relatively much wider compared to Tanystropheus hydroides. Among non-archosauriform archosauromorphs fused parietals also occur in Dinocephalosaurus orientalis (IVPP-V13767), Protorosaurus speneri (NMK S 180, Gottmann-Quesada & Sander, 2009) and rhynchosaurs Dilkes, 1995;Dilkes, 1998). The presence of a pineal foramen is variable among early archosauromorphs, and it is absent in Macrocnemus spp. ...
... The postorbital bar of Azendohsaurus madagaskarensis appears to be somewhat wider than that seen in most archosauromorphs, but less so than in the abovementioned taxa (Flynn et al., 2010). Dilkes, 1998). The exact configuration of the postorbital bar in Tanystropheus longobardicus is unclear since no well-preserved squamosal is currently known for this species , Methods S1). ...
The postcranial morphology of the extremely long-necked Tanystropheus hydroides is well-known, but observations of skull morphology were previously limited due to compression of the known specimens. Here we provide a detailed description of the skull of PIMUZ T 2790, including a partial endocast and endosseous labyrinth, based on synchrotron microtomographic data, and compare its morphology to that of other early Archosauromorpha. In many features, such as the wide and flattened snout and the configuration of the temporal and palatal regions, Tanystropheus hydroides differs strongly from other early archosauromorphs. The braincase possesses a combination of derived archosaur traits, such as the presence of a laterosphenoid and the ossification of the lateral wall of the braincase, but also differs from archosauriforms in the morphology of the ventral ramus of the opisthotic, the horizontal orientation of the parabasisphenoid, and the absence of a clearly defined crista prootica. Tanystropheus hydroides was a ram-feeder that likely caught its prey through a laterally directed snapping bite. Although the cranial morphology of other archosauromorph lineages is relatively well-represented, the skulls of most tanystropheid taxa remain poorly understood due to compressed and often fragmentary specimens. The recent descriptions of the skulls of Macrocnemus bassanii and now Tanystropheus hydroides reveal a large cranial disparity in the clade, reflecting wide ecological diversity, and highlighting the importance of non-archosauriform Archosauromorpha to both terrestrial and aquatic ecosystems during the Triassic.
