Prolacertoides

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Prolacertoides
Temporal range: Early Triassic, Induan
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Prolacertoides skull.png
The holotype skull of Prolacertoides
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauromorpha
Family: incertae sedis
Genus: Prolacertoides
Yang, 1973
Type species
Prolacertoides jimusarensis
Yang, 1973

Prolacertoides is an extinct genus of archosauromorph reptile from the Early Triassic of China, the type species being Prolacertoides jimusarensis. [1] Prolacertoides means 'like Prolacerta ', in reference to Prolacerta, another genus of archosauromorph which Prolacertoides was once believed to have been closely related to. Prolacertoides is known from a single partial skull, IVPP V3233, which was discovered in Xinjiang in northwestern China. The locality of its discovery belongs to the Cangfanggou Group of the Jiucaiyuan Formation, which is dated to the Induan age of the very early Triassic. [2]

Description

A reconstruction of the skull of Prolacertoides Prolacertoides skull reconstruction.png
A reconstruction of the skull of Prolacertoides

IVPP V3233 is a partially flattened and incomplete skull, with some bones being well preserved and others being badly damaged. The snout is tapering and lacks antorbital fenestrae. The anterodorsal edge of each maxilla is convex, in contrast to the concave edge of other basal archosauromorphs. The ascending process of each maxilla is tall and anteroposteriorly broad, reaching the edge of the skull roof. The anterior process of each jugal is long and thin, forming the lower edge of the orbit, unlike in basal saurians. A moderate number of maxillary teeth (approximately 19) are present, but the tooth row does not reach as far back as the orbits. The teeth themselves are straight, conical, and lack serrations, with only the rear teeth being slightly compressed. The nares are long and situated on the edge of the snout. Each nasal widens towards the rear of the skull, forming an anterolaterally-oriented suture with the prefrontal. Each lacrimal is wide and slit-like while the prefrontals are well exposed, traits similar to those of Prolacerta. Each prefrontal is dorsally smooth and convex, possessing a large lateral pit as well as a triangular medial projection which restricts the nasal-frontal suture. This restriction is also found in Trilophosaurus and Gephyrosaurus . Unlike in Prolacerta and basal archosauriforms, there is extensive contact between the pterygoids. The pterygoids and palatines were seemingly toothless, although this observance may be due to poor preservation. The tip of each ectopterygoid expands into a fan-shaped structure, and the suborbital fenestra is very short. [2]

Classification

Prolacertoides was named in 1973 and classified in the family Prolacertidae. The first phylogenetic analyses to include Prolacertoides (published in 1988 and 1997) found it to be more closely related to the Late Triassic archosauromorph Trilophosaurus rather than prolacertids. [3] Another analysis published in 1997 included Prolacertoides but its relationships with other archosauromorphs could not be resolved because few distinctive anatomical characteristics are known. [4] The exact relationships of Prolacertoides were still considered unknown in 2007. [5]

Prolacertoides was redescribed in a 2016 study of archosauromorph and archosauriform systematics. The study also included a set of phylogenetic analyses in an effort to clarify the classification of certain archosauromorphs. However, the large amount of missing data for Prolacertoides forced it to be excluded from most of the analyses, which focused on more complete taxa. The phylogenetic analyses which did include Prolacertoides found that it was an archosauromorph forming a polytomy with Allokotosauria, Tanystropheidae, and Jesairosaurus . In more precise analyses which exclude incomplete or problematic taxa such as Prolacertoides, this polytomy was resolved, with Allokotosauria forming a clade with more advanced archosauromorphs (such as rhynchosaurs and archosauriforms), and Tanystropheidae forming a more basal clade with Jesairosaurus. Due to its omission from these more specific analyses, it is unclear whether Prolacertoides is closer to Allokotosauria or the Tanystropheidae-Jesairosaurus clade. Nevertheless, Prolacertoides was not found in any analysis to be a particularly close relative of its namesake Prolacerta. [2]

Related Research Articles

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<span class="mw-page-title-main">Archosauromorpha</span> Infraclass of reptiles

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<i>Tanystropheus</i> Extinct genus of reptiles

Tanystropheus is an extinct genus of archosauromorph reptile which lived during the Triassic Period in Europe, Asia, and North America. It is recognisable by its extremely elongated neck, longer than the torso and tail combined. The neck was composed of 13 vertebrae strengthened by extensive cervical ribs. Tanystropheus is one of the most well-described non-archosauriform archosauromorphs, known from numerous fossils, including nearly complete skeletons. Some species within the genus may have reached a total length of 6 meters (20 ft), making Tanystropheus the longest non-archosauriform archosauromorph as well. Tanystropheus is the namesake of the family Tanystropheidae, a clade collecting many long-necked Triassic archosauromorphs previously described as "protorosaurs" or "prolacertiforms".

<i>Tasmaniosaurus</i> Extinct genus of reptiles

Tasmaniosaurus is an extinct genus of archosauromorph reptile known from the Knocklofty Formation of West Hobart, Tasmania, Australia. The type species is T. triassicus. This genus is notable not only due to being one of the most complete Australian Triassic reptiles known, but also due to being a very close relative of Archosauriformes. Once believed to be a proterosuchid, this taxon is now believed to have been intermediate between advanced non-archosauriform archosauromorphs such as Prolacerta, and basal archosauriforms such as Proterosuchus. Features traditionally used to define Archosauria and later Archosauriformes, such as the presence of an antorbital fenestra and serrated teeth, are now known to have evolved prior to those groups due to their presence in Tasmaniosaurus.

<i>Kalisuchus</i> Extinct genus of reptiles

Kalisuchus was a genus of basal archosauriform known from remains unearthed from the Arcadia Formation of the Early Triassic of the Crater, Southwest of Rolleston, south central Queensland, Australia. It was named after Kali, the Hindu goddess of destruction, a reference to the very fragmentary nature of its remains. The type species of Kalisuchus is K. rewanensis, which refers to the Rewan Group. The Arcadia formation is dated to the Induan age at the very beginning of the Triassic, making Kalisuchus one of the oldest archosauromorphs known in Australia.

<i>Turfanosuchus</i> Extinct genus of reptiles

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<i>Daemonosaurus</i> Genus of reptiles (fossil)

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<i>Cosesaurus</i> Extinct genus of reptiles

Cosesaurus is a genus of archosauromorph reptiles likely belonging to the family Tanystropheidae. It is known from fossil imprints of a single small skeleton, MGB V1, which was found in Muschelkalk outcrops near the municipalities of Mont-ral and Alcover in Spain. These outcrops are dated to the Ladinian age of the middle Triassic about 242 to 237 million years ago. The specimen is stored at the Museu Martorell, which is now part of the Museu de Ciències Naturals de Barcelona. The poor preservation and likely juvenile nature of the specimen has led to the anatomy of Cosesaurus being misidentified by several different sources. For example, Paul Ellenberger claimed that it was an ancestor to birds in the 1970s, while David Peters claimed that it was a pterosaur ancestor in 2000. Both of these claims contrast with mainstream scientific theories on the origins of either group, and other paleontologists who study the specimen are unable to find the features which Ellenberger or Peters reported to be present. The Ellenberger and Peters hypotheses are thus considered fringe theories with questionable scientific soundness due to their low reproducibility. Mainstream hypotheses for the relations of Cosesaurus generally agree that it is a "protorosaur", specifically a tanystropheid closely related to long-necked reptiles such as Macrocnemus, Tanytrachelos, Tanystropheus, or Langobardisaurus.

<span class="mw-page-title-main">Proterochampsia</span> Extinct clade of reptiles

Proterochampsia is a clade of early archosauriform reptiles from the Triassic period. It includes the Proterochampsidae and probably also the Doswelliidae. Nesbitt (2011) defines Proterochampsia as a stem-based taxon that includes Proterochampsa and all forms more closely related to it than Euparkeria, Erythrosuchus, Passer domesticus, or Crocodylus niloticus. Therefore, the inclusion of Doswelliidae in it is dependent upon whether Doswellia and Proterochampsa form a monophyletic group to the exclusion of Archosauria and other related groups.

<i>Jesairosaurus</i> Extinct genus of reptiles

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<span class="mw-page-title-main">Protorosauria</span> Extinct order of reptiles

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<i>Prolacerta</i> Extinct genus of reptile from the lower Triassic

Prolacerta is a genus of archosauromorph from the lower Triassic of South Africa and Antarctica. The only known species is Prolacerta broomi. The generic name Prolacerta is derived from Latin meaning “before lizard” and its species name broomi is in commemoration of the famous paleontologist Robert Broom, who discovered and studied many of the fossils found in rocks of the Karoo Supergroup. When first discovered, Prolacerta was considered to be ancestral to modern lizards, scientifically known as lacertilians. However, a study by Gow (1975) instead found that it shared more similarities with the lineage that would lead to archosaurs such as crocodilians and dinosaurs. Prolacerta is considered by modern paleontologists to be among the closest relatives of the Archosauriformes.

<i>Pamelaria</i> Extinct genus of reptiles

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<i>Asperoris</i> Extinct genus of reptiles

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<i>Pectodens</i> Extinct genus of reptiles

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<i>Kadimakara australiensis</i> Extinct species of reptile

Kadimakara is an extinct genus of early archosauromorph reptile from the Arcadia Formation of Queensland, Australia. It was seemingly a very close relative of Prolacerta, a carnivorous reptile which possessed a moderately long neck. The generic name Kadimakara references prehistoric creatures from Aboriginal myths which may have been inspired by ice-age megafauna. The specific name K. australiensis relates to the fact that it was found in Australia. Prolacerta and Kadimakara were closely related to the Archosauriformes, a successful group which includes archosaurs such as crocodilians, pterosaurs, and dinosaurs.

Boreopricea is an extinct genus of archosauromorph reptile from the Early Triassic of arctic Russia. It is known from a fairly complete skeleton discovered in a borehole on Kolguyev Island, though damage to the specimen and loss of certain bones has complicated study of the genus. Boreopricea shared many similarities with various other archosauromorphs, making its classification controversial. Various studies have considered it a close relative of Prolacerta, tanystropheids, both, or neither. Boreopricea is unique among early archosauromorphs due to possessing contact between the jugal and squamosal bones at the rear half of the skull.

<i>Rugarhynchos</i> Extinct genus of reptiles

Rugarhynchos is an extinct genus of doswelliid archosauriform from the Late Triassic of New Mexico. The only known species is Rugarhynchos sixmilensis. It was originally described as a species of Doswellia in 2012, before receiving its own genus in 2020. Rugarhynchos was a close relative of Doswellia and shared several features with it, such as the absence of an infratemporal fenestra and heavily textured skull bones. However, it could also be distinguished by many unique characteristics, such as a thick diagonal ridge on the side of the snout, blunt spikes on its osteoderms, and a complex suture between the quadratojugal, squamosal, and jugal. Non-metric multidimensional scaling and tooth morphology suggest that Rugarhynchos had a general skull anatomy convergent with some crocodyliforms, spinosaurids, and phytosaurs. However, its snout was somewhat less elongated than those other reptiles.

<i>Puercosuchus</i> Extinct genus of reptile

Puercosuchus is an extinct genus of archosauromorph reptile from the Late Triassic (Norian) of what is now Arizona, North America. It includes only the type species P. traverorum, and was described and named in 2022. Puercosuchus is known mainly from two bonebeds in the Blue Mesa Member of the Chinle Formation, preserving the mixed remains of multiple individuals in each one representing almost the entire skeleton. It is a member of the Azendohsauridae, a clade of Triassic reptiles that was initially recognised by adaptations for herbivory. However, Puercosuchus and its close relatives in the subclade Malerisaurinae retained the carnivorous diet and body form ancestral to archosauromorphs. Unlike non-malerisaurine azendohsaurids, Puercosuchus had a long and shallow snout with sharp, blade-like teeth similar to those of carnivorous dinosaurs. Despite its seemingly ancestral morphology and ecology, Puercosuchus is the youngest known genus of azendohsaurid in the world. The discovery of Puercosuchus allowed palaeontologists to recognise similar bones and teeth that had been collected from Late Triassic southwestern North America in the past as belonging to it or similar animals, acting as a sort of "rosetta stone" for malerisaurine azendohsaurid anatomy.

References

  1. Young, C.-C. (1973). "The discovery of prolacertilian skull from Jimusar, Xinjiang". Vertebrata PalAsiatica. 11 (1): 46–48.
  2. 1 2 3 Ezcurra, Martín D. (2016-04-28). "The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms". PeerJ. 4: e1778. doi: 10.7717/peerj.1778 . PMC   4860341 . PMID   27162705.
  3. Benton, M.J.; Allen, J.L. (1997). "Boreopricea from the Lower Triassic of Russia, and the relationships of the prolacertiform reptiles". Palaeontology. 40 (4): 931–953.
  4. Jalil, N. E. (1997). "A new prolacertiform diapsid from the Triassic of North Africa and the interrelationships of the Prolacertiformes". Journal of Vertebrate Paleontology. 17 (3): 506–525. Bibcode:1997JVPal..17..506J. doi:10.1080/02724634.1997.10010998.
  5. Li, C.; Zhao, L.; Wang, L. (2007). "A new species of Macrocnemus (Reptilia: Protorosauria) from the Middle Triassic of southwestern China and its palaeogeographical implication". Science in China Series D: Earth Sciences. 50 (11): 1601–1605. Bibcode:2007ScChD..50.1601L. doi:10.1007/s11430-007-0118-5. S2CID   131694121.