Pectodens

Pectodens; Temporal range: Anisian, 244 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Holotype fossil
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	† Dinocephalosauridae
Genus:	† Pectodens ; Li et al., 2017
Type species
	Pectodens zhenyuensis; Li et al., 2017

Last updated December 03, 2023

Pectodens (meaning "comb tooth") is an extinct genus of archosauromorph reptile which lived during the Middle Triassic in China. The type and only species of the genus is P. zhenyuensis, named by Chun Li and colleagues in 2017. It was a member of the Archosauromorpha, specifically part of the unnatural grouping Protorosauria. However, an unusual combination of traits similar (such as the long neck) and dissimilar (such as the absence of a hook on the fifth metatarsal bone) to other protorosaurs initially led to confusion over its evolutionary relationships. In 2021, it was placed in a newly-established group, Dinocephalosauridae, along with its closest relative Dinocephalosaurus .

A small, slender animal measuring 38 centimetres (15 in) long, Pectodens was named after the peculiar comb-like arrangement of long, conical teeth present in its mouth. Unlike Dinocephalosaurus and the other reptiles that it was preserved with, well-developed joints and claw-like digits indicate that Pectodens was entirely terrestrial. However, its presence in marine deposits suggests that lived relatively close to the coastline. Its skeleton was also poorly ossified, which is typically a trait of aquatic animals, but this may have been due to the young age of the only known specimen instead.

Discovery and naming

Pectodens is known from one specimen, consisting of a well-preserved and almost complete skeleton. The fossil is preserved on two separate blocks that broke cleanly, but details of the pelvis were lost in the process. Additionally, the left femur is missing, as is part of one cervical. The specimen is catalogued as IVPP V18578, being stored in the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China. It was described by Chun Li, Nicholas Fraser, Olivier Rieppel, Li-Jun Zhao, and Li-Ting Wang in a 2017 research paper published in the Journal of Paleontology.^[1]

The specimen itself was found in Luoping County in Yunnan, China. It is part of the "Panxian-Luoping fauna", a faunal assemblage which is part of Member II of the Anisian (Middle Triassic) Guanling Formation. Conodont biostratigraphy (based on the presence of Nicoraella kockeli )^[2] and radiometric dating ^[3] have dated the assemblage in Luoping to 244 million years old. Predominant deposits in Member II of the Guanling Formation consist of grey layers of marly limestone and limestone.^[1]^[4]

In their 2017 description of IVPP V18578, Li and colleagues named the new genus Pectodens, from Latin pecto- ("comb") and dens ("tooth"), in reference to the animal's characteristic comb-like arrangement of elongated teeth. They also named the type species Pectodens zhenyuensis after Zhenyu Li, who had assisted with the collection of the specimen.^[1]

Description

Pectodens was a small animal with a slender build, measuring roughly 38 centimetres (15 in) long. Overall, its skeleton was poorly ossified, although this may have been a consequence of the young age of the specimen.^[5] The skull measured 25.7 mm (1.01 in) long, while the lower jaw was probably 25–26 mm (0.98–1.02 in) long when complete. Uniquely, numerous conical teeth in the jaws of Pectodens formed a comb-like structure. These teeth had weakly-developed broad enamel ridges. There were 10 teeth in each premaxilla at the front of the jaw, and at least 24 more on the maxilla further back. There were also teeth on the palate, with at least 15 being present on the pterygoid bone. Additionally, the eye socket was very large, measuring 10.5 mm (0.41 in) long, although this again may have been due to the animal's immaturity. Meanwhile, the rear (temporal) region of the skull was quite short.^[1] Similar to Dinocephalosaurus , the bony nostrils of Pectodens were retracted from the tip of the snout by the width of the premaxilla, and both lacked the backward-pointing process of the jugal bone seen in other archosauromorph reptiles.^[5]

The neck and tail of Pectodens were long, with the former being the same length as the torso. In life, it had 66 to 68 vertebrae, with 11-12 neck vertebrae, 11-13 back vertebrae, 2 hip vertebrae, and 41 tail vertebrae. The neck vertebrae had low neural spines, like Tanystropheus . The neck ribs were generally also long, having short forward processes and long rear processes that bridged two to three vertebral joints each. Similar to Dinocephalosaurus, Czatkowiella , Sclerostropheus , and Tanytrachelos , the forward processes were free of the vertebral bodies and extended to the preceding vertebrae.^[5] Meanwhile, the transverse processes of the back vertebrae were uniquely long and pronounced, ending in sub-circular facet joints that connected with the rounded heads of the ribs. Also like Tanystropheus, the transverse processes of the tail became gradually reduced alongside the forward processes of the chevrons, disappearing by the 35th tail vertebra.^[1]

Like Tanystropheus and Macrocnemus , the scapula was low-slung^[6] with a half-moon shape unique among archosauromorphs. Like Tanystropheus, Macrocnemus, Amotosaurus , Langobardisaurus and Planocephalosaurus , there was a notch in the bottom of the ischium that demarcated a rear projection.^[5] The long bones of the forelimbs had expanded and robust top ends; the deltopectoral crest on the humerus was also rather prominent. The humerus was longer than the ulna and radius, while the tibia and fibula were conversely slightly longer than the femur. An empty gap in the wrist of an otherwise articulated hand suggests that not all of the wrist bones were ossified due to immaturity.^[5] Likewise, the distal tarsals also appear to have been missing from the ankle, but the remaining bones articulated directly with the foot. Unusually, there was no "hook" on the fifth metatarsal bone, unlike Tanystropheus. The hands and feet each had five digits, with the five digits respectively having 2, 3, 4, 5, and 4 phalanges (although there may have only been 3 in the fifth digits of the hands).^[1]

Classification

Protorosauria was a diverse group of archosauromorph reptiles that lived during the Permian and Triassic periods. The classification of Pectodens was complicated by the presence of both characteristics similar to the Protorosauria as well as characteristics which would be expected in a more basal (less specialised) archosauromorph. Like Tanystropheus, Macrocnemus, and other protorosaurs, the neck vertebrae were long with low neural spines, and bore cervical ribs that bridged multiple joints.^[7]^[8]^[9] These same characteristics previously allowed Li, Fraser, and Rieppel to assign Dinocephalosaurus to the Protorosauria.^[10] Yet, in Pectodens, the puboischiadic plate in the hip (formed from the pubis and ischium) did not appear to bear a perforation known as the thyroid fenestra, the astragalus and calcaneum of the ankle were simple and rounded, and the fifth metatarsal was not hooked.^[1]

Poor preservation in some regions also hampered the classification of Pectodens. The blocks containing the type specimen had split through the puboischiadic plate, for instance; the neural spines of the back vertebrar were also not visible, which means that they could not be compared with those of the Tanystropheidae (which were tall and elongated). Also, the uncertainty in the number of phalanges in the fifth digit of the hand had an impact; most protorosaurs had three, while Pectodens may have had three or four depending on whether a breakage is interpreted as obscuring one single phalanx or two overlapping phalanges. Considering all of this uncertainty, Li and colleagues thus only tentatively considered Pectodens a protorosaur.^[1]

Nevertheless, a number of subsequent phylogenetic analyses included Pectodens. Starting in the 2000s, the Protorosauria was increasingly being considered as not forming a natural monophyletic grouping, with the defining genus of Protorosaurus considered as having been more basal (less specialised) than other traditional members of the group.^[11]^[12] The opposite was also true of Prolacerta , which was used to define the alternate grouping Prolacertiformes.^[13]^[14] In 2018, a phylogenetic analysis by Martín Ezcurra and Richard J. Butler found Pectodens in a large polytomy with other members of the Tanystropheidae, with Dinocephalosaurus and Trachelosaurus being the sister groups of Tanystropheidae.^[15] In 2021, Stephan Spiekman and colleagues performed multiple analyses using new datasets that incorporated different species and anatomical characteristics. They consistently found a group formed by Pectodens and Dinocephalosaurus, which they named Dinocephalosauridae after the latter. Some variants of their analysis found either Sclerostropheus or "Tanystropheus" antiquus as members of the Dinocephalosauridae, and either Fuyuansaurus or Jesairosaurus as their closest relative. Other analyses found these, with the exception of Jesairosaurus, to be tanystropheids. The phylogenetic tree recovered by one of their analyses is shown below.^[5]

Dinocephalosauridae

	Pectodens

	Dinocephalosaurus

Tanystropheidae

	Macrocnemus bassanii

	Macrocnemus fuyuanensis

Macrocnemus obristi

Ozimek

	Sclerostropheus

	Raibliania

	AMNH FARB 7206 (referred to Tanytrachelos)

	Tanytrachelos

	Tanystropheus hydroides

	GMPKU P 1527 (referred to T. hydroides)

	Tanystropheus longobardicus

Crocopoda

Allokotosauria

Rhynchosauria

	Teyujagua

	Archosauriformes

"Protorosauria"

Paleobiology

Judging by the slender limbs with robust joints and claw-tipped elongate digits, Pectodens was most likely an entirely terrestrial animal. It exhibits no adaptations for an aquatic lifestyle, unlike other archosauromorphs in the Panxian-Luoping biota (the amphibious Qianosuchus , for instance, or the marine Dinocephalosaurus ).^[1]

Paleoecology

Pectodens on the land surrounding a shallow sea that covered much of southern China during the Middle Triassic. Four major landmasses were present in this region, which had been formed by a mountain-building event known as the Indosinian orogeny: Khamdian to the west, Jiangnan occupying a central position, Yunkai to the south, and Cathaysia to the east. The Lagerstätten of Panxian and Luoping were laid down as fossil-bearing sediments on the western edge of an oceanic basin located between Khamdian and Jiangnan, known as the Nanpanjiang Basin.^[4]^[16]^[17]^[18] All of these geological features are part of the South China Block, a tectonic plate presently composed of the Yangtze Craton and the South China Fold Belt.^[16]^[19]

Although Pectodens was fully terrestrial, it was preserved alongside the other fauna of Luoping within a small oceanic intraplatform basin, in which preservation was facilitated by the presence of anoxic sediments. Reptiles constitute a minority of fossils, at 0.07% of 19,759 specimens found at Luoping.^[20] They include Pectodens and Dinocephalosaurus along with the mixosaurian ichthyosaurs Mixosaurus cf. panxianensis and Phalarodon atavus ; the pachypleurosaurs Dianmeisaurus gracilis and Dianopachysaurus dingi ; the saurosphargids Largocephalosaurus polycarpon and Sinosaurosphargis yunguiensis ; the nothosaurs Nothosaurus zhangi and a species of Lariosaurus ; other sauropterygians Atopodentatus unicus , Dawazisaurus brevis , and Diandongosaurus acutidentatus ; and an archosaur related to Qianosuchus .^[4]^[21] By comparison, 93.7% of Luoping's fossils are arthropods, including decapods, isopods, cycloids, mysidaceans, clam shrimp, ostracods, millipedes, and horseshoe crabs. Fish consist of 25 taxa in 9 families and form 3.66% of fossil specimens, including saurichthyids, palaeoniscids, birgeriids, perleidids, eugnathids, semionotids, pholidopleurids, peltopleurids, and coelacanths. Molluscs, including bivalves and gastropods account for 1.69% alongside ammonoids and belemnoids. Echinoderms such as crinoids, starfish, and sea urchins, as well as branchiopods, are rare, and probably did not originate from local waters. Branches and leaves from conifers have also been found, representing coastal forests located less than 10 km (6.2 mi) away from the intraplatform basin.^[20] The proximity of the shoreline to this basin is supported by the occurrence of Pectodens.^[1]

Related Research Articles

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

Dinocephalosaurus is a genus of long necked, aquatic protorosaur that inhabited the Triassic seas of China. The genus contains the type and only known species, D. orientalis, which was named by Li in 2003. Unlike other long-necked protorosaurs, Dinocephalosaurus convergently evolved a long neck not through elongation of individual neck vertebrae, but through the addition of neck vertebrae that each had a moderate length. As indicated by phylogenetic analyses, it belonged in a separate lineage that also included at least its closest relative Pectodens, which was named the Dinocephalosauridae in 2021. Like tanystropheids, however, Dinocephalosaurus probably used its long neck to hunt, utilizing the fang-like teeth of its jaws to ensnare prey; proposals that it employed suction feeding have not been universally accepted. It was probably a marine animal by necessity, as suggested by the poorly-ossified and paddle-like limbs which would have prevented it from going ashore.

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

Archosauromorpha is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs rather than lepidosaurs. Archosauromorphs first appeared during the late Middle Permian or Late Permian, though they became much more common and diverse during the Triassic period.

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".

Protorosaurus is an extinct genus of reptile. Members of the genus lived during the late Permian period in what is now Germany and Great Britain. Once believed to have been an ancestor to lizards, Protorosaurus is now known to be one of the oldest and most primitive members of Archosauromorpha, the group that would eventually lead to archosaurs such as crocodilians and dinosaurs.

Macrocnemus is an extinct genus of archosauromorph reptile known from the Middle Triassic of Europe and China. Macrocnemus is a member of the Tanystropheidae family and includes three species. Macrocnemus bassanii, the first species to be named and described, is known from the Besano Formation and adjacent paleontological sites in the Italian and Swiss Alps. Macrocnemus fuyuanensis, on the other hand, is known from the Zhuganpo Formation in southern China. A third species, Macrocnemus obristi, is known from the Prosanto Formation of Switzerland and is characterized by gracile limbs. The name Macrocnemus is Greek for "long tibia".

Langobardisaurus is an extinct genus of tanystropheid archosauromorph reptile, with one known species, L. pandolfii. Its fossils have been found in Italy and Austria, and it lived during the Late Triassic period, roughly 228 to 201 million years ago. The Langobardisaurus was first discovered by Italian paleontologist Silvio Renesto in 1994 from the Calcare di Zorzino Formation in Northern Italy.

The Guanling Formation is a Middle Triassic geologic formation in southwestern China.

Sinosaurosphargis is an extinct genus of basal marine saurosphargid reptile known from the Middle Triassic Guanling Formation of Yunnan and Guizhou Provinces, southwestern China. It contains a single species, Sinosaurosphargis yunguiensis.

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.

Protorosauria is an extinct, likely paraphyletic group of basal archosauromorph reptiles from the latest Middle Permian to the end of the Late Triassic of Asia, Europe and North America. It was named by the English anatomist and paleontologist Thomas Henry Huxley in 1871 as an order, originally to solely contain Protorosaurus. Other names which were once considered equivalent to Protorosauria include Prolacertiformes and Prolacertilia.

Pamelaria is an extinct genus of allokotosaurian archosauromorph reptile known from a single species, Pamelaria dolichotrachela, from the Middle Triassic of India. Pamelaria has sprawling legs, a long neck, and a pointed skull with nostrils positioned at the very tip of the snout. Among early archosauromorphs, Pamelaria is most similar to Prolacerta from the Early Triassic of South Africa and Antarctica. Both have been placed in the family Prolacertidae. Pamelaria, Prolacerta, and various other Permo-Triassic reptiles such as Protorosaurus and Tanystropheus have often been placed in a group of archosauromorphs called Protorosauria, which was regarded as one of the most basal group of archosauromorphs. However, more recent phylogenetic analyses indicate that Pamelaria and Prolacerta are more closely related to Archosauriformes than are Protorosaurus, Tanystropheus, and other protorosaurs, making Protorosauria a polyphyletic grouping.

Tanystropheidae is an extinct family of mostly marine archosauromorph reptiles that lived throughout the Triassic Period. They are characterized by their long, stiff necks formed from elongated cervical vertebrae with very long cervical ribs. Some tanystropheids such as Tanystropheus had necks that were several meters long, longer than the rest of their bodies.

Fuyuansaurus is an extinct genus of "protorosaur" reptiles known from the Middle Triassic Zhuganpo Formation of southern China. Fuyuansaurus was first named by Nicholas C. Fraser, Olivier Rieppel and Li Chun in 2013 and the type species is Fuyuansaurus acutirostris.

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

Eorasaurus is an extinct genus of archosauromorph reptile known from the middle Late Permian of Tatarstan, European Russia. It contains a single species, Eorasaurus olsoni. When originally described by Sennikov (1997), Eorasaurus was identified as an early archosauromorph and assigned to the family Protorosauridae, Ezcurra et al. (2014) and Ezcurra (2016) later reclassified Eorasaurus and placed it within the group Archosauriformes. Eorasaurus is based solely on scant fossil material from the neck region, and is thus considered an unstable taxon in phylogenetic analyses. If Eorasaurus is an archosauriform, it would be the oldest known member of the group and would pre-date the previous record holder.

Saurosphargidae is an extinct family of marine reptiles known from the Early Triassic and early Middle Triassic of Europe and China.

Ozimek is a genus of sharovipterygid archosauromorph reptile, known from Late Triassic deposits in Poland and closely related to the Kyrgyzstani Sharovipteryx. It contains one species, O. volans, named in 2016 by Jerzy Dzik and Tomasz Sulej. Like Sharovipteryx, Ozimek had long, slender limbs with the hindlimbs longer than the forelimbs; the hindlimbs likely supported gliding membranes as fossilized in Sharovipteryx. Another unusual characteristic was the shoulder girdle, where the massive coracoids formed a shield-like structure covering the bottom of the shoulder region that would have limited mobility. In other respects, such as its long neck, it was a typical member of the non-natural grouping Protorosauria. Phylogenetic analysis has indicated that it, possibly along with Sharovipteryx, may have been an unusual member of the protorosaur group Tanystropheidae, although further study of its anatomy is needed to resolve its precise relationships.

The Zhuganpo Formation is a Triassic geologic unit found in southern China. It has historically been known as the Zhuganpo Member of the Falang Formation. A diverse fossil assemblage known as the Xingyi biota or Xingyi Fauna can be found in the upper part of the Zhuganpo Formation. Fossils of the Xingyi biota include articulated skeletons of marine reptiles, abundant fish, and a plentiful assortment of invertebrates indicating a Ladinian to Carnian age for the sediments of the formation.

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

Dinocephalosauridae is an extinct clade of marine and terrestrial archosauromorph reptiles that lived throughout the Triassic period. Like tanystropheids, they are characterized by their long necks, lengthened by either addition of cervical vertebrae or elongation of the individual bones.

Gracilicollum is an extinct genus of likely tanystropheid archosauromorph from the Middle Triassic (Anisian) Guanling Formation of China. The genus contains a single species, G. latens, known from a skull and partial neck.

Austronaga is an extinct genus of dinocephalosaurid archosauromorph reptile from the Middle Triassic (Anisian) Guanling Formation of China. The genus contains a single species, A. minuta, known from a partial skull, as well as vertebrae from the tail and neck. Austronaga was significantly smaller than the coeval Dinocephalosaurus.

References

1 2 3 4 5 6 7 8 9 10 Li, C.; Fraser, N.C.; Rieppel, O.; Zhao, L.-J.; Wang, L.-T. (2017). "A new diapsid from the Middle Triassic of southern China". Journal of Paleontology. 91 (6): 1306–1312. doi: 10.1017/jpa.2017.12 .
↑ Zhang, Q.-Y.; Zhou, C.-Y.; Lu, T.; Xie, T.; Lou, X.-Y.; Liu, W.; Sun, Y.-Y.; Huang, J.-Y.; Zhao, L.-S. (2009). "A conodont-based Middle Triassic age assignment for the Luoping Biota of Yunnan, China". Science in China Series D: Earth Sciences. 52 (10): 1673–1678. Bibcode:2009ScChD..52.1673Z. doi:10.1007/s11430-009-0114-z. S2CID 129857181.
↑ Liu, J.; Organ, C.L.; Benton, M.J.; Brandley, M.C.; Aitchison, J.C. (2017). "Live birth in an archosauromorph reptile". Nature Communications. 8: 14445. Bibcode:2017NatCo...814445L. doi:10.1038/ncomms14445. ISSN 2041-1723. PMC 5316873 . PMID 28195584.
1 2 3 Benton, M.J.; Zhang, Q.; Hu, S.; Chen, Z.-Q.; Wen, W.; Liu, J.; Zhou, C.; Xie, T.; Tong, J.; Choo, B. (2013). "Exceptional vertebrate biotas from the Triassic of China, and the expansion of marine ecosystems after the Permo-Triassic mass extinction". Earth-Science Reviews. 123: 199–243. Bibcode:2013ESRv..125..199B. doi:10.1016/j.earscirev.2013.05.014.
1 2 3 4 5 6 Spiekman, S.N.F.; Fraser, N.C.; Scheyer, T.M. (2021). "A new phylogenetic hypothesis of Tanystropheidae (Diapsida, Archosauromorpha) and other "protorosaurs", and its implications for the early evolution of stem archosaurs". PeerJ. 9: e11143. doi: 10.7717/peerj.11143 . PMC 8101476 . PMID 33986981.
↑ Nosotti, S. (2007). "Tanystropheus longobardicus (Reptilia, Protorosauria): re-interpretations of the anatomy based on new specimens from the Middle Triassic of Besano (Lombardy, northern Italy)". Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano. 35 (3): 1–88.
↑ 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. doi:10.1080/02724634.1997.10010998.
↑ Benton, M.J.; Allen, J.L. (1997). "Boreopricea from the Lower Triassic of Russia, and the relationships of the prolacertiform reptiles". Palaeontology. 40: 931–953.
↑ Evans, S.E. (1988). "The early history and relationships of the Diapsida". In Benton, M.J. (ed.). The Phylogeny and Classification of the Tetrapods. Vol. 1. Oxford: Clarendon Press. pp. 221–253.
↑ Rieppel, O.; Li, C.; Fraser, N.C (2008). "The Skeletal Anatomy of the Triassic Protorosaur Dinocephalosaurus orientalis Li, from the Middle Triassic of Guizhou Province, Southern China". Journal of Vertebrate Paleontology. 28 (1): 95–110. doi:10.1671/0272-4634(2008)28[95:TSAOTT]2.0.CO;2. JSTOR 30126337. S2CID 86026836.
↑ Pritchard, A.C; Turner, A.H.; Nesbitt, S.J.; Irmis, R.B.; Smith, N.D. (2015). "Late Triassic tanystropheids (Reptilia, Archosauromorpha) from northern New Mexico (Petrified Forest Member, Chinle Formation) and the biogeography, functional morphology, and evolution of Tanystropheidae". Journal of Vertebrate Paleontology. 35 (2): e911186. doi:10.1080/02724634.2014.911186. S2CID 130089407.
↑ Ezcurra, M.D. (2016). "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.
↑ Modesto, S.P.; Sues, H.D. (2004). "The skull of the Early Triassic archosauromorph reptile Prolacerta broomi and its phylogenetic significance". Zoological Journal of the Linnean Society. 140 (3): 335–351. doi: 10.1111/j.1096-3642.2003.00102.x .
↑ Gottmann-Quesada, A.; Sander, P.M. (2009). "A redescription of the early archosauromorph Protorosaurus speneri Meyer, 1832, and its phylogenetic relationships". Palaeontographica Abteilung A. 287 (4–6): 123–200. doi:10.1127/pala/287/2009/123.
↑ Ezcurra, M.D.; Butler, R.J. (2018). "The rise of the ruling reptiles and ecosystem recovery from the Permo-Triassic mass extinction". Proceedings of the Royal Society B. 285 (1880): 20180361. doi:10.1098/rspb.2018.0361. PMC 6015845 . PMID 29899066.
1 2 Lehrmann, D.J.; Minzoni, M.; Enos, P.; Yu, Y.-Y.; Wei, J.-Y.; Li, R.-X. (2009). "Triassic depositional history of the Yangtze platform and Great Bank of Guizhou in the Nanpanjiang basin of South China". Journal of Earth Sciences and Environment. 31 (4): 344–367.
↑ Lehrmann, D.J.; Payne, J.L.; Felix, S.V.; Dillett, P.M.; Wang, H.; Yu, Y.; Wei, J. (2003). "Permian–Triassic Boundary Sections from Shallow-Marine Carbonate Platforms of the Nanpanjiang Basin, South China: Implications for Oceanic Conditions Associated with the End-Permian Extinction and Its Aftermath". PALAIOS. 18 (2): 138–152. Bibcode:2003Palai..18..138L. CiteSeerX 10.1.1.486.1486 . doi:10.1669/0883-1351(2003)18<138:PBSFSC>2.0.CO;2. S2CID 130715861.
↑ Lehrmann, D.J.; Payne, J.L.; Pei, D.; Enos, P.; Druke, D.; Steffen, K.; Zhang, J.; Wei, J.; Orchard, M.J.; Ellwood, B. (2007). "Record of the end-Permian extinction and Triassic biotic recovery in the Chongzuo-Pingguo platform, southern Nanpanjiang basin, Guangxi, South China". Palaeogeography, Palaeoclimatology, Palaeoecology. 252 (1): 200–217. Bibcode:2007PPP...252..200L. doi:10.1016/j.palaeo.2006.11.044.
↑ Lehrmann, D.J.; Enos, P.; Payne, J.L.; Montgomery, P.; Wei, J.; Yu, Y.; Xiao, J.; Orchard, M.J. (2005). "Permian and Triassic depositional history of the Yangtze platform and Great Bank of Guizhou in the Nanpanjiang basin of Guizhou and Guangxi, South China" (PDF). Albertiana. 33: 149–168.
1 2 Hu, S.-X.; Zhang, Q.-Y.; Chen, Z.-Q.; Zhou, C.-Y.; Lü, T.; Xie, T.; Wen, W.; Huang, J.-Y.; Benton, M.J. (2011). "The Luoping biota: exceptional preservation, and new evidence on the Triassic recovery from end-Permian mass extinction". Proceedings of the Royal Society B. 278 (1716): 2274–2282. doi:10.1098/rspb.2010.2235. PMC 3119007 . PMID 21183583.
↑ Liu, Q.; Yang, T.; Cheng, L.; Benton, M.J.; Moon, B.C.; Yan, C.; An, Z.; Tian, L. (2021). "An injured pachypleurosaur (Diapsida: Sauropterygia) from the Middle Triassic Luoping Biota indicating predation pressure in the Mesozoic". Scientific Reports. 11 (1): 21818. Bibcode:2021NatSR..1121818L. doi:10.1038/s41598-021-01309-z. PMC 8575933 . PMID 34750442.

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[li2017-1] 1 2 3 4 5 6 7 8 9 10 Li, C.; Fraser, N.C.; Rieppel, O.; Zhao, L.-J.; Wang, L.-T. (2017). "A new diapsid from the Middle Triassic of southern China". Journal of Paleontology. 91 (6): 1306–1312. doi: 10.1017/jpa.2017.12 .

[zhang2009-2] Zhang, Q.-Y.; Zhou, C.-Y.; Lu, T.; Xie, T.; Lou, X.-Y.; Liu, W.; Sun, Y.-Y.; Huang, J.-Y.; Zhao, L.-S. (2009). "A conodont-based Middle Triassic age assignment for the Luoping Biota of Yunnan, China". Science in China Series D: Earth Sciences. 52 (10): 1673–1678. Bibcode:2009ScChD..52.1673Z. doi:10.1007/s11430-009-0114-z. S2CID 129857181.

[liu2017-3] Liu, J.; Organ, C.L.; Benton, M.J.; Brandley, M.C.; Aitchison, J.C. (2017). "Live birth in an archosauromorph reptile". Nature Communications. 8: 14445. Bibcode:2017NatCo...814445L. doi:10.1038/ncomms14445. ISSN 2041-1723. PMC 5316873 . PMID 28195584.

[benton2013-4] 1 2 3 Benton, M.J.; Zhang, Q.; Hu, S.; Chen, Z.-Q.; Wen, W.; Liu, J.; Zhou, C.; Xie, T.; Tong, J.; Choo, B. (2013). "Exceptional vertebrate biotas from the Triassic of China, and the expansion of marine ecosystems after the Permo-Triassic mass extinction". Earth-Science Reviews. 123: 199–243. Bibcode:2013ESRv..125..199B. doi:10.1016/j.earscirev.2013.05.014.

[spiekman2021-5] 1 2 3 4 5 6 Spiekman, S.N.F.; Fraser, N.C.; Scheyer, T.M. (2021). "A new phylogenetic hypothesis of Tanystropheidae (Diapsida, Archosauromorpha) and other "protorosaurs", and its implications for the early evolution of stem archosaurs". PeerJ. 9: e11143. doi: 10.7717/peerj.11143 . PMC 8101476 . PMID 33986981.

[nosotti2007-6] Nosotti, S. (2007). "Tanystropheus longobardicus (Reptilia, Protorosauria): re-interpretations of the anatomy based on new specimens from the Middle Triassic of Besano (Lombardy, northern Italy)". Memorie della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano. 35 (3): 1–88.

[jalil1997-7] 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. doi:10.1080/02724634.1997.10010998.

[benton1997-8] Benton, M.J.; Allen, J.L. (1997). "Boreopricea from the Lower Triassic of Russia, and the relationships of the prolacertiform reptiles". Palaeontology. 40: 931–953.

[evans1988-9] Evans, S.E. (1988). "The early history and relationships of the Diapsida". In Benton, M.J. (ed.). The Phylogeny and Classification of the Tetrapods. Vol. 1. Oxford: Clarendon Press. pp. 221–253.

[rieppel2008-10] Rieppel, O.; Li, C.; Fraser, N.C (2008). "The Skeletal Anatomy of the Triassic Protorosaur Dinocephalosaurus orientalis Li, from the Middle Triassic of Guizhou Province, Southern China". Journal of Vertebrate Paleontology. 28 (1): 95–110. doi:10.1671/0272-4634(2008)28[95:TSAOTT]2.0.CO;2. JSTOR 30126337. S2CID 86026836.

[pritchard2015-11] Pritchard, A.C; Turner, A.H.; Nesbitt, S.J.; Irmis, R.B.; Smith, N.D. (2015). "Late Triassic tanystropheids (Reptilia, Archosauromorpha) from northern New Mexico (Petrified Forest Member, Chinle Formation) and the biogeography, functional morphology, and evolution of Tanystropheidae". Journal of Vertebrate Paleontology. 35 (2): e911186. doi:10.1080/02724634.2014.911186. S2CID 130089407.

[ezcurra2016-12] Ezcurra, M.D. (2016). "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.

[modesto2004-13] Modesto, S.P.; Sues, H.D. (2004). "The skull of the Early Triassic archosauromorph reptile Prolacerta broomi and its phylogenetic significance". Zoological Journal of the Linnean Society. 140 (3): 335–351. doi: 10.1111/j.1096-3642.2003.00102.x .

[gottmannquesada2009-14] Gottmann-Quesada, A.; Sander, P.M. (2009). "A redescription of the early archosauromorph Protorosaurus speneri Meyer, 1832, and its phylogenetic relationships". Palaeontographica Abteilung A. 287 (4–6): 123–200. doi:10.1127/pala/287/2009/123.

[ezcurra2018-15] Ezcurra, M.D.; Butler, R.J. (2018). "The rise of the ruling reptiles and ecosystem recovery from the Permo-Triassic mass extinction". Proceedings of the Royal Society B. 285 (1880): 20180361. doi:10.1098/rspb.2018.0361. PMC 6015845 . PMID 29899066.

[lehrmann2009-16] 1 2 Lehrmann, D.J.; Minzoni, M.; Enos, P.; Yu, Y.-Y.; Wei, J.-Y.; Li, R.-X. (2009). "Triassic depositional history of the Yangtze platform and Great Bank of Guizhou in the Nanpanjiang basin of South China". Journal of Earth Sciences and Environment. 31 (4): 344–367.

[lehrmann2003-17] Lehrmann, D.J.; Payne, J.L.; Felix, S.V.; Dillett, P.M.; Wang, H.; Yu, Y.; Wei, J. (2003). "Permian–Triassic Boundary Sections from Shallow-Marine Carbonate Platforms of the Nanpanjiang Basin, South China: Implications for Oceanic Conditions Associated with the End-Permian Extinction and Its Aftermath". PALAIOS. 18 (2): 138–152. Bibcode:2003Palai..18..138L. CiteSeerX 10.1.1.486.1486 . doi:10.1669/0883-1351(2003)18<138:PBSFSC>2.0.CO;2. S2CID 130715861.

[lehrmann2007-18] Lehrmann, D.J.; Payne, J.L.; Pei, D.; Enos, P.; Druke, D.; Steffen, K.; Zhang, J.; Wei, J.; Orchard, M.J.; Ellwood, B. (2007). "Record of the end-Permian extinction and Triassic biotic recovery in the Chongzuo-Pingguo platform, southern Nanpanjiang basin, Guangxi, South China". Palaeogeography, Palaeoclimatology, Palaeoecology. 252 (1): 200–217. Bibcode:2007PPP...252..200L. doi:10.1016/j.palaeo.2006.11.044.

[lehrmann2005-19] Lehrmann, D.J.; Enos, P.; Payne, J.L.; Montgomery, P.; Wei, J.; Yu, Y.; Xiao, J.; Orchard, M.J. (2005). "Permian and Triassic depositional history of the Yangtze platform and Great Bank of Guizhou in the Nanpanjiang basin of Guizhou and Guangxi, South China" (PDF). Albertiana. 33: 149–168.

[hu2011-20] 1 2 Hu, S.-X.; Zhang, Q.-Y.; Chen, Z.-Q.; Zhou, C.-Y.; Lü, T.; Xie, T.; Wen, W.; Huang, J.-Y.; Benton, M.J. (2011). "The Luoping biota: exceptional preservation, and new evidence on the Triassic recovery from end-Permian mass extinction". Proceedings of the Royal Society B. 278 (1716): 2274–2282. doi:10.1098/rspb.2010.2235. PMC 3119007 . PMID 21183583.

[liu2021-21] Liu, Q.; Yang, T.; Cheng, L.; Benton, M.J.; Moon, B.C.; Yan, C.; An, Z.; Tian, L. (2021). "An injured pachypleurosaur (Diapsida: Sauropterygia) from the Middle Triassic Luoping Biota indicating predation pressure in the Mesozoic". Scientific Reports. 11 (1): 21818. Bibcode:2021NatSR..1121818L. doi:10.1038/s41598-021-01309-z. PMC 8575933 . PMID 34750442.

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