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A new prolacertiform diapsid from the Triassic of North Africa and the interrelationships of the Prolacertiformes

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Journal of Verterbrate Paleontology
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Nour-Eddine Jalil
Nour-Eddine Jalil
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Abstract

A new diapsid reptile, Jesairosaurus lehmani, gen. et sp. nov., is described on the basis of cranial and postcranial remains from the base of the Zarzaitine Series (Triassic) of Algeria. Jesairosaurus is a small prolacertiform with a low skull and an elongated neck; the snout is narrow and elongated and the post-orbital region short and narrow; the quadratojugal is lost; the posterior process of the jugal is reduced and spur-shaped; the hind-limb is large in comparison with the forelimb and the rest of the postcranial skeleton. The relationships of basal archosauromorphs and the interrelationships of the prolacertiforms are examined. The analysis of 71 binary characters leads to the identification of Jesairosaurus lehmani as a prolacertiform and suggests that Prolacertiformes forms a monophyletic group within the Archosauromorpha. The analysis indicates that the Rhynchosauria is the sister group of a clade comprising Trilophosaurus, Prolacertiformes, and Proterosuchus. The Choristodera is the most plesiomorphic taxon within the archosauromorphs. Jesairosaurus is most closely related to Malerisaurus langstoni while Boreopricea is closely related to the (Cosesaurus(Tanystropheus longobardicus, Tany trachelos)) clade, and Langobardisaurus and Macrocnemus are the successive out-groups of this clade. Protorosaurus is the most plesiomorphic of the best known Prolacertiformes. The relationships of the poorly known prolacertiforms Kadimakara, Prolacertoides, Malutinisuchus, and probably Trachelosaurus remain unresolved.
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A New Prolacertiform Diapsid from the Triassic of North Africa and the Interrelationships
of the Prolacertiformes
Author(s): Nour-Eddine Jalil
Source:
Journal of Vertebrate Paleontology,
Vol. 17, No. 3 (Sep. 4, 1997), pp. 506-525
Published by: The Society of Vertebrate Paleontology
Stable URL: http://www.jstor.org/stable/4523832
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... 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. ...
... One study included 11 "protorosaurs" (excluding the poorly known Prolacertoides) and three outgroups and 48 morphological characters (Benton & Allen, 1997). 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. ...
... 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. ...
A new phylogenetic hypothesis of Tanystropheidae (Diapsida, Archosauromorpha) and other “protorosaurs”, and its implications for the early evolution of stem archosaurs
Article
Full-text available
  • May 2021
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.
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... Since Huene (1944), the material attributed to Trachelosaurus fischeri has not been studied in detail. Although it was incorporated in some early cladistic analyses and recovered among traditional "protorosaurs", it was found as highly unstable and omitted from most of the final results (Benton & Allen, 1997;Evans, 1988;Jalil, 1997;Rieppel et al., 2003). Due to a lack of information on this taxon, it was omitted from more recent phylogenetic studies (e.g., Ezcurra, 2016;Pritchard et al., 2015;Spiekman et al., 2021b), and its exact morphology, mode of life, and phylogenetic affinities remained unclear. ...
A redescription of Trachelosaurus fischeri from the Buntsandstein (Middle Triassic) of Bernburg, Germany: the first European Dinocephalosaurus‑like marine reptile and its systematic implications for long‑necked early archosauromorphs
Article
Full-text available
  • Mar 2024
Some of the earliest members of the archosaur-lineage (i.e., non-archosauriform archosauromorphs) are characterised by an extremely elongated neck. Recent fossil discoveries from the Guanling Formation (Middle Triassic) of southern China have revealed a dramatic increase in the known ecomorphological diversity of these extremely long-necked archosauromorphs, including the fully marine and viviparous Dinocephalosaurus orientalis. These recent discoveries merit a reinvestigation of enigmatic Triassic diapsid fossils from contemporaneous European deposits housed in historical collections. Here, we provide a redescription of Trachelosaurus fischeri, represented by a single, disarticulated specimen first described in 1918. Due to its unique morphology, which includes short, bifurcating cervical ribs, and a high presacral vertebral count, this taxon has been referred to either as a “protorosaurian” archosauromorph or a sauropterygian. Our revision clearly shows that Trachelosaurus represents the first unambiguous Dinocephalosaurus- like archosauromorph known from outside the Guanling Formation. Our finding has important systematic implications. Trachelosauridae Abel, 1919 represents the senior synonym for the recently identified Dinocephalosauridae Spiekman, Fraser and Scheyer, 2021. Based on our phylogenetic analyses, which employ two extensive datasets, we also corroborate previous findings that tanystropheids and trachelosaurids represent two families within a larger monophyletic group among non-crocopodan archosauromorphs, which is here named Tanysauria (clade nov.). Trachelosauridae is minimally composed of Trachelosaurus fischeri, Dinocephalosaurus orientalis, Pectodens zhenyuensis, and Austronaga minuta, but one of our analyses also found a probably taxonomically broader clade that may also include Gracilicollum latens and Fuyuansaurus acutirostris. Trachelosaurus fischeri considerably expands the known spatial and temporal range of Trachelosauridae to the earliest Anisian and the Central European Basin. Our findings add to the growing evidence for the presence of a diverse group of fully marine reptiles during the Middle Triassic
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... The base of the Lower Sandstone of the Zarzaitine Series in southeastern Algeria yields the amphibians Oldenwaldia and "Wellesaurus" (an indeterminate heylerosaurid according to Damiani 2001b) as well as a brachyopid?, trematosaurid and the prolacertiform Jesairosaurus (Lehman, 1957(Lehman, , 1971Jalil, 1990Jalil, , 1993Jalil, , 1994Jalil, , 1997Jalil, , 1999Welles, 1993). The record of Oldenwaldia supports a Nonesian age assignment, but there are no data from Algeria to develop a cross correlation to the SGCS. ...
Definition, Correlation and Age of the Cynognathus Assemblage Zone, Lower-Middle Triassic of Pangea
Article
  • Dec 2022
  • Paleontol J
The Cynognathus Assemblage Zone (AZ) has been recognized for more than 100 yr and is one of the most durable tetrapod biostratigraphic concepts of the Triassic. Long treated as a single biostratigraphic unit, the Cynognathus AZ is now divided into three subzones (in ascending order), A, B and C. The South African Cynognathus AZ can be correlated across Pangea to tetrapod assemblages in Algeria, and Zambia. Various index taxa found in the subzones of the Cynognathus AZ in the Karoo basin provide multiple and reinforcing correlations, and independent age constraints combined with marine records of Parotosuchus associated with ammonoids indicate that subzone A is of Olenekian age, primarily Spathian, but perhaps as old as part or all of the Smithian. The early Anisian age of subzone B lacks robust support and is largely based on its stratigraphic position in the Karoo basin between late Olenekian (subzone A) and late Anisian (subzone C) assemblages. In China a subzone B assemblage of the lower Ermay-ing Formation is overlain by a late Anisian assemblage of the upper Ermaying Formation correlative to sub-zone C. The Russian Eryosuchus fauna, which is very likely of Anisian age, is at least in part correlative with subzone B, and palynostratigraphy in Australia also indicates an Anisian age for strata (Ashfield Slate) that contain subzone B and C tetrapods. Correlation of subzone C to the later Anisian is primarily supported by a radioisotopic age from China that indicates a subzone C tetrapod assemblage is ~ 243 Ma. The beginning of Perovkan time is close to the beginning of the Anisian, so the Nonesian is the time equivalent to subzone A, and subzones B and C are of Perovkan age. Nevertheless, how close the base of subzone B of the Cynognathus AZ may be to the base of the Anisian is not clear, and a stronger basis is needed to identify the beginning of the Anisian and the beginning of the Perovkan land-vertebrate faunachron in the time interval represented by subzone B of the Cynognathus AZ.
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... The dorsal centra is dorsoventrally flat in the vast majority of non-archosauriform diapsids. In the archosauromorphs Protorosaurus speneri, Jesairosaurus lehmani Jalil, 1997, andPamelaria dolichotrachela Sen, 2003, this character state is also described as a shallow and poorly rimmed oval fossa, as what is seen in some archosauriforms (Ezcurra et al., 2010;Ezcurra, 2016). ...
Archosauriform remains from the Lower Triassic Sanga do Cabral Formation of Brazil
Article
Early Triassic archosauriform remains are often related to the Proterosuchidae and the Erythrosuchidae, common stem-archosaurs in the aftermath of the end-Permian extinction event. South American proterosuchid remains are rare, with only a few specimens from the Lower Triassic Sanga do Cabral Formation briefly mentioned in literature. The Lower Triassic Sanga do Cabral Formation has a growing fossil record, thus far composed of procolophonids, temnospondyls, and early-branching archosauromorphs. In this work, new materials referred to cf. Chasmatosuchus and cf. Proterosuchus (Archosauriformes) are described, representing the first conclusive archosauriform records from the Lower Triassic of Brazil. Proterosuchids are among the stratigraphically oldest Archosauriformes, with their earliest unambiguous occurrences coming from the uppermost Permian of Russia. This clade is widely spread among well-explored Lower Triassic formations, flourishing during the recovery phase from the end-Permian mass extinction. The presence of nonarchosaurian archosauriforms in southwestern Gondwana reinforces the rapid diversification of archosauromorphs during the Early Triassic. The Sanga do Cabral Formation fossil assemblage is becoming important for understanding how the initial adaptive radiation of archosauromorphs took place.
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... It is also present to a lesser degree in the parietals of Protorosaurus speneri, in which However, the morphology of Tanystropheus hydroides differs distinctly from that seen in the parietals of smaller early archosauromorphs (e.g. Macrocnemus bassanii, Prolacerta broomi, Jesairosaurus lehmani, and Tanystropheus longobardicus; PIMUZ T 2484; Jalil, 1997;Miedema et al., 2020;Modesto & Sues, 2004). In these taxa, the supratemporal fossae form less of a depression and are largely dorsally facing, and the posterolateral processes are much narrower. ...
The cranial morphology of Tanystropheus hydroides (Tanystropheidae, Archosauromorpha) as revealed by synchrotron microtomography
Article
Full-text available
  • Nov 2020
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.
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... Both parietals are present in PIMUZ T 2477. The parietals are unfused, as in the tanystropheid Tanytrachelos ahynis (YPM 7,482), Jesairosaurus lehmani (ZAR 07), Prolacerta broomi, and allokotosaurs among non-archosauriform archosauromorphs(Fig. 3)34,37,40,49,50 . They are well preserved and in close association with each other. ...
Cranial morphology of the tanystropheid Macrocnemus bassanii unveiled using synchrotron microtomography
Article
Full-text available
  • Jul 2020
The genus Macrocnemus is a member of the Tanystropheidae, a clade of non-archosauriform archosauromorphs well known for their very characteristic, elongated cervical vertebrae. Articulated specimens are known from the Middle Triassic of Alpine Europe and China. Although multiple articulated specimens are known, description of the cranial morphology has proven challenging due to the crushed preservation of the specimens. Here we use synchrotron micro computed tomography to analyse the cranial morphology of a specimen of the type species Macrocnemus bassanii from the Besano Formation of Monte San Giorgio, Ticino, Switzerland. The skull is virtually complete and we identify and describe the braincase and palatal elements as well the atlas-axis complex for the first time. Moreover, we add to the knowledge of the morphology of the skull roof, rostrum and hemimandible, and reconstruct the cranium of M. bassanii in 3D using the rendered models of the elements. The circumorbital bones were found to be similar in morphology to those of the archosauromorphs Prolacerta broomi and Protorosaurus speneri. In addition, we confirm the palatine, vomer and pterygoid to be tooth-bearing palatal bones, but also observed heterodonty on the pterygoid and the palatine.
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Reply to Müller et al 2023 - The origin of pterosaurs
Preprint
Full-text available
  • Oct 2023
Müller et al.1 recently described a Late Triassic partial skeleton they named Venetoraptor gassena. The authors linked their find to the origin of dinosaurs and pterosaurs while omitting three Middle and Late Triassic taxa that share more traits pterosaurs. Coseaurus, Sharovipteryx and Longisquama (Figs. 1, 2) are known from articulated fossils that preserve bones and soft tissues otherwise only reported in pterosaurs. Unfortunately, the omission of these pertinent taxa in the search for pterosaur ancestors has been an academically approved tradition documented in the following timeline of pterosaur origin studies.
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A re-assessment of the osteology and phylogenetic relationships of the enigmatic, large-headed reptile Sphodrosaurus pennsylvanicus (Late Triassic, Pennsylvania, USA) indicates archosauriform affinities
Article
Full-text available
  • May 2022
Most Triassic terrestrial diapsids belong to two clades, Lepidosauromorpha or (the more diverse) Archosauromorpha. Nevertheless, the phylogenetic relationships of some Triassic diapsids have remained uncertain for decades because of the lack of preservation of phylogenetically relevant anatomical regions or because of unusual combinations of features. One of these enigmatic forms is the small-sized Sphodrosaurus pennsylvanicus from the Upper Triassic Hammer Creek Formation of the Newark Supergroup in Pennsylvania (USA). It was first identified as a procolophonid parareptile, later as a probable rhynchosaur archosauromorph, and more recently as an indeterminate neodiapsid. Here we revise the anatomy of Sphodrosaurus pennsylvanicus in order to include it for the first time in a quantitative phylogenetic analysis, which is focused on Permo–Triassic neodiapsids. Sphodrosaurus pennsylvanicus is recovered in this analysis as a doswelliid proterochampsian within Archosauromorpha. As a result, this taxon is added to the list of doswelliids known from the Carnian–Norian of the eastern and south-western USA. Previous authors recognized that the most unusual feature of Sphodrosaurus pennsylvanicus is its proportionally very large skull. Phylogenetic generalized least squares regressions confirmed that Sphodrosaurus pennsylvanicus has a larger skull than the vast majority of Permo–Triassic diapsids. Optimization in the phylogeny of the skull width to presacral length ratio shows the most likely scenario is that the extremely broad skull of Sphodrosaurus pennsylvanicus is autapomorphic, but it is not unique among archosauromorphs, being paralleled by hyperodapedontine rhynchosaurs and the proterochampsian Proterochampsa barrionuevoi. Exploration of a morphospace of linear measurements shows that Sphodrosaurus pennsylvanicus shares strong similarities with the probably semi-aquatic Proterochampsa barrionuevoi, suggesting that the former species may have had a similar mode of life. A linear discriminant analysis of ungual functional categories found that the only preserved ungual of Sphodrosaurus pennsylvanicus was suitable for digging or some other way of substrate processing.
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Eifelosaurus triadicus Jaekel, 1904, a “forgotten” reptile from the Upper Buntsandstein (Triassic: Anisian) of the Eifel region, Germany
Article
  • Dec 2021
We provide a detailed description of the poorly known reptile Eifelosaurus triadicus Jaekel, 1904 from the Upper Buntsandstein (Triassic: early Anisian) of Oberbettingen in the southwestern Eifel region of Rhineland-Palatinate, Germany. The holotype and only known specimen is a partial postcranial skeleton exposed in ventral view. Since its original description Eifelosaurus triadicus has been almost completely ignored in the literature. Our phylogenetic analysis recovered this taxon within Rhynchosauria and Rhynchosauridae, as the sister taxon to the clade comprising Stenaulorhynchinae and hyperodapedontine-line rhynchosaurids. A unique combination of character states allows distinguishing Eifelosaurus triadicus from other rhynchosaur species with preserved matching postcranial bones. Thus, we tentatively consider this taxon valid until more information about the postcrania of other Early to Middle Triassic rhynchosaurs becomes available. Eifelosaurus triadicus represents a paleobiogeographically important record, showing that rhynchosaurs had already attained a broad paleolatitudinal distribution by the early Middle Triassic.
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The origin of Pterosaurs
Article
  • Aug 2021
  • EARTH-SCI REV
Our understanding of the pterosaurs' place within the reptilian lineage has had a long and complex history. The unusual morphology of pterosaurs, which is inextricably linked to their habit of powered flight, has generated numerous proposals over the years regarding their exact origin and systematic position. Though it was concluded early on in pterosaur research history that these animals represented a group of derived flying reptiles, their exact origination remained mysterious for a long time and is still somewhat controversial. A rough consensus has now been reached that pterosaurs are derived archosaurs and are likely close relatives of the dinosaurs, united with them in the clade Ornithodira, though some still challenge this view. The anatomical evidence in support of this position close to Dinosauria is also admittedly fairly limited at present, largely owing to a lack of any clear-cut transitional ‘proto-pterosaur’ taxa (albeit that some fragmentary specimens have been suggested to represent exactly this). Differing hypotheses have also recently been put forward as to the exact interrelationships between the pterosaurs and other non-dinosaurian and dinosaurian ornithodirans. Here the previous hypotheses of where pterosaurs fit into the reptilian lineage and the anatomical evidence in support of the current hypotheses are reviewed. Results of new analyses are included that looked to test the origin and systematic position of the Pterosauria using an expanded version of a large anatomical dataset of archosaurs, within which several previously unconsidered early pterosaur taxa and a suit of new anatomical characters were considered. The analyses in this study support the close affinities between pterosaurs and dinosauriforms within Ornithodira; Pterosauria is recovered as the sister-taxon to Lagerpetidae. Such a result suggests that the clade Pterosauria belongs with Lagerpetidae as part of a broader Pterosauromorpha that then, with Dinosauriformes, falls within Ornithodira. The anatomical evidence in support of this position within Ornithodira is also discussed in detail.
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On two small saurian skulls (Amniota, Diapsida) from the Middle Triassic of Algeria
Article
  • Jan 1990
Two skulls referred to small saurians from the Middle Triassic Zarzaitine Series (Algeria) are described and their attribution to either the Archosauromorpha or Lepidosauromorpha is discussed. There is an abridged English version. -English summary
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On the occurrence of the Brachyopoidea (Vertebrata, Tetrapoda, Temnospondyli) from the Zarzaitine Series, Triassic, Algeria
Article
  • Jan 1994
Two fragments of the dermal skull-roof and isolated teeth of a Brachyopoidea are described from the Zarzaitine Series (Middle Triassic, Algeria), and their stratigraphical significance is discussed. -English summary
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Morphological study and phylogenetic significance of the braincase of an archosauriform (Diapsida, Archosauromorpha) of the Zarzaitine series, Algeria
Article
  • Jan 1995
Abundant, but fragmentary material collected from the Triassic of the Zarzaitine series (Triassic, Algeria), includes the archosauriform braincase described here. This braincase is attributed to a clade Archosauria + Proterochampsidae on the basis of four character-states. Its well developed crista prootica, the extensive participation of the para-basisphenoid in the well ossified lateral wall, the occurrence of a metotic fenestra divided into two openings, and the foramen for the internal carotid artery which enters the body of the basisphenoid laterally to the basipterygoid process constitute those characters. -from English summary
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