New Osteological and Phylogenetic Review of the Triassic Loricatan Prestosuchus chiniquensis from Brazil

Roberto-Da-Silva, L., Müller , R. T., Gallo de França, M. A., Cabreira, S. F., and Dias-Da-Silva, S. 2018. An impressive skeleton of the giant top predator Prestosuchus chiniquensis (Pseudosuchia: Loricata) from the Triassic of Southern Brazil, with phylogenetic remarks. Historical Biology (Early Online).

Abstract - In the present contribution, we aim to present the osteology of ‘ULBRA-PVT-281’, which comprises the best-preserved skeleton of Prestosuchus chiniquensis ever found. ULBRA-PVT-281 combines the morphology of two classic specimens referred to P. chiniquensis, UFRGS-PV-0156-T and UFRGSPV- 0152-T, reunited in a single operational taxonomic unit (OTU) in previous phylogenetic studies. Therefore, the new specimen reinforces the combination of both specimens. We performed a phylogenetic analysis, combining the information of these three specimens plus braincase data from a fourth specimen, UFRGS-PV-0629-T, into a new P. chiniquensis terminal taxon. Moreover, our analysis also included some new taxa potentially related to P. chiniquensis. As a result, we found a topology slightly distinct from previous studies, where Ticinosuchus ferox is the basalmost member of Loricata, which also includes the new combined P. chiniquensis. Our results place P. chiniquensis, Luperosuchus fractus, and Saurosuchus galilei distributed in a pectinate paraphyletic pattern towards Crocodylomorpha. On the other hand, a constrained analysis forcing the monophyly of these taxa demands just a single extra step. Therefore, both scenarios are plausible and agree with the placement of P. chiniquensis within Loricata, whereas T. ferox nests in Loricata only in the unconstrained analysis.

Fuyuanichthys wangi A New Ginklymodian Fish from the Middle Triassic of China

Xu, G., Ma, X., and Y. Ren. 2018. Fuyuanichthys wangi gen. et sp. nov. from the Middle Triassic (Ladinian) of China highlights the early diversification of ginglymodian fishes. PeerJ 6:e6054 https://doi.org/10.7717/peerj.6054

Abstract - A series of well-preserved fossil assemblages from the Middle Triassic marine rock succession in Southwest China provide unique evidences for studying the early evolution of holostean fishes, including Halecomorphi (e.g., bownfin) and Ginglymodi (e.g., gars). Ginglymodi have the earliest record in the early Middle Triassic (Anisian, ∼244 Ma) of China, represented by Kyphosichthys and Sangiorgioichthys sui from Yunnan and S. yangjuanensis from Guizhou. Here, we report the discovery of a new ginglymodian, Fuyuanichthys wangi gen. et sp. nov., based on 22 well-preserved specimens from the lower part of the Zhuganpo member of the Falang Formation in eastern Yunnan and western Guizhou, which documents the first discovery of convincing ginglymodians from the late Middle Triassic (Ladinian, ∼240 Ma) Xingyi biota in China. Fuyuanichthys possesses a unique combination of features that easily distinguishes it from other ginglymodians, such as presence of a median gular and short and edentulous maxillae, and absence of a supramaxilla and supraorbitals. As one of the smallest known ginglymodians with a maximum standard length of ∼75 mm, the new finding further supports that the Middle Triassic Ginglymodi have a relatively small range of body sizes compared with the Halecomorphi from the same ecosystems in China. Results of a phylogenetic analysis recover Fuyuanichthys as a sister taxon to Kyphosichthys at the ginglymodian stem, and provide new insights into the early evolution of this clade.

Systematics of Putative Euparkeriids from the Triassic of China

Sookias, R. B., Sullivan, C., Liu, J., and R. J. Butler. 2014. Systematics of putative euparkeriids (Diapsida: Archosauriformes) from the Triassic of China. PeerJ 2:e658 doi:http://dx.doi.org/10.7717/peerj.658

Abstract - The South African species Euparkeria capensis is of great importance for understanding the early radiation of archosauromorphs (including archosaurs) following the Permo–Triassic mass extinction, as most phylogenetic analyses place it as the sister taxon to crown group Archosauria within the clade Archosauriformes. Although a number of species from Lower–Middle Triassic deposits worldwide have been referred to the putative clade Euparkeriidae, the monophyly of Euparkeriidae is controversial and has yet to be demonstrated by quantitative phylogenetic analysis. Three Chinese taxa have been recently suggested to be euparkeriids: Halazhaisuchus qiaoensis, ‘Turfanosuchus shageduensis’, and Wangisuchus tzeyii, all three of which were collected from the Middle Triassic Ermaying Formation of northern China. Here, we reassess the taxonomy and systematics of these taxa. We regard Wangisuchus tzeyii as a nomen dubium, because the holotype is undiagnostic and there is no convincing evidence that the previously referred additional specimens represent the same taxon as the holotype. We also regard ‘Turfanosuchus shageduensis’ as a nomen dubium as we are unable to identify any diagnostic features. We refer the holotype to Archosauriformes, and more tentatively to Euparkeriidae. Halazhaisuchus qiaoensis and the holotype of 'Turfanosuchus shageduensis’ are resolved as sister taxa in a phylogenetic analysis, and are in turn the sister taxon to Euparkeria capensis, forming a monophyletic Euparkeriidae that is the sister to Archosauria+Phytosauria. This is the first quantitative phylogenetic analysis to recover a non-monospecific, monophyletic Euparkeriidae, but euparkeriid monophyly is only weakly supported and will require additional examination. Given their similar sizes, stratigraphic positions and phylogenetic placement, the holotype of ‘Turfanosuchus shageduensis’ may represent a second individual of Halazhaisuchus qiaoensis, but no apomorphies or unique character combination can be
identified to unambiguously unite the two. Our results have important implications for understanding the species richness and palaeobiogeographical distribution of early archosauriforms.

Nundasuchus songeaensis, a New Archosauriform from the Middle Triassic of Tanzania and its Implications for the Phylogeny of the Archosauria

Nesbitt, S. J., Sidor, C. A., Angielczyk, K. D., Smith, R. M. H., and L. A. Tsuji. 2014. A new archosaur from the Manda beds (Anisian, Middle Triassic) of southern Tanzania and its implications for character state optimizations at Archosauria and Pseudosuchia. Journal of Vertebrate Paleontology 34:1357-1382 DOI:10.1080/02724634.2014.859622

Abstract - The presence of early pseudosuchians and avemetatarsalians in Anisian beds of Africa demonstrates that the archosaur radiation was well underway by the beginning of the Middle Triassic. The rapid radiation produced a variety of forms, but many of the unique, well-diagnosed
Late Triassic clades (e.g., Aetosauria, Ornithosuchidae) lack diagnosable members from the Middle Triassic. Here, we introduce a new Middle Triassic archosaur, Nundasuchus songeaensis, gen. et sp. nov., with an unusual mix of apomorphic character states found within Pseudosuchia and just outside Archosauria. The holotype consists of partial skeleton, including representative postcranial elements and parts of the skull. We added Nundasuchus songeaensis, gen. et sp. nov., into the two most comprehensive early archosaur phylogenetic data sets available, and in both analyses the new taxon falls within Pseudosuchia. However, a number of plesiomorphic archosaurian character states (e.g., posterolaterally directed tuber of the calcaneum) optimize as local autapomorphies of the new taxon within Pseudosuchia in our analyses. Therefore, we tested alternative hypotheses of relationships for the new taxon by utilizing constraint trees. The analyses resulted in little change in the relationships and structure of other Triassic archosaur clades, but changed optimizations of certain character states and character support at the base of Pseudosuchia and Archosauria. Our analyses suggest that the
complex evolution of character-state changes at the base of Archosauria is inhibiting our understanding of the relationships of early Pseudosuchia and, in turn, Archosauria.

Antarctosuchus polyodon, a new Temnospondyl from the Middle Triassic of Antarctica and Evidence for the Provincialization of the Temnospondyl Assemblages of Gondwana

I've always been interested in the Triassic rocks of Antarctica since as a work-study student at the Museum of Northern Arizona in the 1990s, I was tasked with returning a loan back to the American Museum of Natural History. Turns out it was Edwin Colbert's collection of material from Antarctica.  I was spellbound handling and packing away leaves of Glossopteris and specimens of Thrinaxodon and Dicynodon. These were specimens I had read about when I was younger that helped nail down the theory of plate tectonics, and here I was handling them and packing them for shipment (I hope they made it OK). In graduate school in the late 1990s we were tasked with writing a mock NSF proposal.  Mine dealt with collecting fossils in the Transantarctic Mountains and I'm happy to say it was the only one 'funded' by the professor, but of course I did not really get to go. As a result I'm always envious when  I read about Antarctic work.

This is a paper in the new issue of the Journal of Vertebrate Paleontology describing a new temnospondyl from the Middle Triassic of Antarctica.  This new taxon, Antarctosuchus polyodon, is based on a well preserved skull and a reconstruction is provided below courtesy of Christian Sidor.

This new taxon and its phylogenetic relationships suggests that the Gonwanan temnospondyl faunal assemblages were more provincial than the synapsid assemblages.

Sidor, C. A., Steyer, J. S., and W. R. Hammer. 2014. A new capitosaurid temnospondyl from the Middle Triassic Upper Fremouw Formation of Antarctica. Journal of Vertebrate Paleontology 34(3):539-548. DOI:10.1080/02724634.2013.808205

Abstract - We describe a new capitosauroid temnospondyl, Antarctosuchus polyodon, gen. et sp. nov., on the basis of a large and relatively complete skull from the upper Fremouw Formation of Antarctica. The new species is characterized by its possession of numerous, extremely small maxillary, palatine, and ectopterygoid teeth, a dental pattern that suggests specialization on small prey items, possibly invertebrates. The taxon is also characterized by a parachoanal tooth row that extends far posterior to the choana and occipital condyles set close to the midline. A combination of features, including a flat skull and low occiput together with well-developed sensory canals, suggests an aquatic lifestyle. We address the phylogenetic relationships of Antarctosuchus by adding it to a recent cladistic analysis of Capitosauria. The revised data set includes 27 taxa and 53 characters. The results of this analysis place Antarctosuchus within a clade of derived Triassic stereospondyls as the sister taxon to Paracyclotosaurus crookshanki from the Triassic Denwai Formation of India. To date, the upper Fremouw Formation has yielded two endemic temnospondyl species (viz., Kryostega collinsoni and Antarctosuchus polyodon), although indeterminate remains referred to benthosuchids and a cranial fragment assigned to Parotosuchus sp. have also been noted. In contrast to the broadly distributed therapsid taxa recognized from the Middle Triassic of Antarctica (e.g., Cynognathus, Diademodon), the temnospondyl fauna suggests more limited interchange with other coeval southern Pangean basins (e.g., Karoo, Luangwa, Ruhuhu, Waterberg).

A New Specimen of the Middle Triassic Archosauriform Shansisuchus shansisuchus from China

Wang, R., Xu, S., , Wu, X., Li, C., and S. Wang. 2013. A New Specimen of Shansisuchus shansisuchus Young, 1964 (Diapsida: Archosauriformes) from the Triassic of Shanxi, China. Acta Geologica Sinica (English Edition) 87:1185-1197 DOI: 10.1111/1755-6724.12145

Abstract - Shansisuchus shansisuchus Young, 1964 was restudied on the basis of a new specimen. Some anatomical features that were either briefly or not described at all in the original study were detailed. The new specimen not only provides further information on the skull anatomy and the vertebral column but also expands the range of the geographical distribution of the taxon. With new information, the diagnosis of S. shansisuchus was emended and its phylogenetic relationships were further analyzed. S. shansisuchus differs from other archosauriforms primarily in the presence of a large subnarial fenestra anterior to the antorbital fenestra, tongue- n-groove articulations between the ascending process of the premaxilla and nasal and between the premaxilla and maxilla, a tall and posterodorsally directed ascending process of the maxilla, a knee-shaped process of the postorbital projecting into the orbit, a broad descending process of squamosal distally well forked and a large, deeply bow-shaped intercentrum tightly anchoring/capping the sharp ventral edges of two neighboring centra together in cervical and at least first eight dorsal vertebrae. With additional information derived from the new specimen, the phylogenetic relationships of S. shansisuchus were reanalyzed; it is closely related to Erythrosuchus-Vjushkovia clade.

A New Protorosaur from the Middle Triassic of China

Fraser, N. C., Rieppel, O., and L. Chun. 2013. A long-snouted protorosaur from the Middle Triassic of southern China. Journal of Vertebrate Paleontology 33:1120-1126 DOI:10.1080/02724634.2013.764310

Abstract - A new protorosaur is described on the basis of a single specimen from the Ladinian of southern China. Although it has been greatly crushed, it still preserves clear details of the skull and axial skeleton. It possesses a neck that is longer than the trunk and is similar to tanystropheids in having 12 or 13 cervicals. Unusual among protorosaurs, the new form has an elongate snout. It also lacks a clear thyroid fenestra, although there is a slight separation of the pubis and ischium close to the pubic symphysis. The new form adds to the growing diversity and disparity of protorosaur taxa from the Middle Triassic of southern China.

A New Silesaurid from the Middle Triassic of Zambia and Evidence for Rapid Diversification of Silesauridae

Peecook, B. R., Sidor, C. A., Nesbitt, S. J., Smith, R. M. H., Steyer, J. S., and K. D. Angielczyk. 2013. A new silesaurid from the upper Ntawere Formation of Zambia (Middle Triassic) demonstrates the rapid diversification of Silesauridae (Avemetatarsalia, Dinosauriformes) Journal of Vertebrate Paleontology 33:1127-1137 DOI:10.1080/02724634.2013.755991 


Abstract - Recent discoveries have shown that non-dinosaurian dinosauromorphs were morphologically diverse, globally distributed, and have a stratigraphic range extending into the Upper Triassic. Silesauridae, the sister group to Dinosauria, contains at least seven species. Here we describe Lutungutali sitwensis, gen. et sp. nov., the first silesaurid from the upper portion of the Ntawere Formation of the Luangwa Basin, Zambia. The upper Ntawere Formation has been correlated with subzone C of the Cynognathus Assemblage Zone of the Karoo Basin in South Africa and the Lifua Member of the Manda beds in the Ruhuhu Basin in Tanzania, both of which are considered Anisian in age and the latter has yielded the silesaurid Asilisaurus kongwe. The results of our phylogenetic analysis, including a new pelvic character, allies Lutungutali with Upper Triassic silesaurids such as Silesaurus, Sacisaurus, and Eucoelophysis rather than with the possibly coeval Asilisaurus. The Zambian silesaurid shares a laterally oriented brevis fossa on the ilium and a transversely thin ischium in cross-section with Upper Triassic forms. Silesaurids were more diverse during their early evolution in the Anisian than previously suspected. Lutungutali and Asilisaurus are the two oldest known members of the bird-line archosaurs represented by body fossils. Together they show that a subclade of bird-line archosaurs was diversifying soon after its origin, building further support for the rapid diversification of Archosauria in the wake of the Permo-Triassic extinction.

Redescription of the Middle Triassic Diapsid Megachirella wachtleri, an Early Branching Lepidosauromorph

Renesto, S.,  and M. Bernardi. 2013. Redescription and phylogenetic relationships of Megachirella wachtleri Renesto et Posenato, 2003 (Reptilia, Diapsida). Paläontologische Zeitschrift. DOI: 10.1007/s12542-013-0194-0
Abstract - Megachirella wachtleri Renesto et Posenato, 2003, a well preserved partial reptile skeleton from the Middle Triassic of the Dolomites (N. Italy), was originally considered a lepidosauromorph, but no phylogenetic analysis was carried out. Consequently, the taxon was overlooked in later phylogenetic analyses of the Diapsida. Here, the holotype and only known specimen of M. wachtleri is redescribed, allowing an investigation of its phylogenetic relationships. Phylogenetic analyses confirm that Megachirella is a lepidosauromorph close to the crown group lepidosaurs (Squamata + Rhynchocephalia). Megachirella enhances our knowledge of the series of morphological modifications that led to the origin of the Lepidosauria, the most diverse clade of extant reptiles.

Two New Early Archosaur Papers

These are the last two articles from the forthcoming volume titled "Anatomy, Phylogeny and Palaeobiology of Early Archosaurs and their Kin". The book should be available for purchase soon from the Geological Society of London.

Liparini, A., and C. L. Schultz. 2013. A reconstruction of the thigh musculature of the extinct pseudosuchian Prestosuchus chiniquensis from the Dinodontosaurus Assemblage Zone (Middle Triassic Epoch), Santa Maria 1 Sequence, southern Brazil. From Nesbitt, S. J., Desojo, J. B. & Irmis, R. B. (eds) Anatomy, Phylogeny and Palaeobiology of Early Archosaurs and their Kin. Geological Society, London, Special Publications, 379. http://sp.lyellcollection.org/content/early/2013/06/13/SP379.20.abstract 

Abstract - Prestosuchus chiniquensis is an extinct species of terrestrial archosaur from the Middle Triassic Epoch restricted to southern Brazil. In this paper the thigh musculature of P. chiniquensis is reconstructed based on a well-preserved specimen and on myological descriptions of extant birds and crocodylians. Among the 16 analysed muscular groups, 13 were recognized as present and homologous to both extant groups of archosaurs, and two only to the crocodylian line of archosaurs, so that 15 muscular groups were reconstructed in the fossil specimen. Morphological particularities of the pelvic girdle and the hindlimbs of P. chiniquensis gave a distinct arrangement for the muscular origin and insertion sites, leading to different lines of action and functions when compared with extant archosaurs. The comparison between extinct and extant archosaurs showed a basal condition sustained in some aspects, such as the morphology of the femur and the flexion of the knee, although other aspects were considered as derived, such as the morphology of the pubis and ischium, and their associated muscle origin locations.

Raugust, T., Lacerda, M., and C. L. Schultz. 2013. The first occurrence of Chanaresuchus bonapartei Romer 1971 (Archosauriformes, Proterochampsia) of the Middle Triassic of Brazil from the Santacruzodon Assemblage Zone, Santa Maria Formation (Paraná Basin). From Nesbitt, S. J., Desojo, J. B. & Irmis, R. B. (eds) Anatomy, Phylogeny and Palaeobiology of Early Archosaurs and their Kin. Geological Society, London, Special Publications, 379.
http://sp.lyellcollection.org/content/early/2013/06/13/SP379.22.abstract

Abstract - Proterochampsians are basal archosauriforms whose record is restricted to the Middle and Upper Triassic in Argentina and Brazil. They are quadruped forms that present characteristics consistent with a semi-aquatic lifestyle, such as an anteroposteriorly elongated skull that is flattened dorsoventrally with dorsally located orbits. In 2003, specimen UFRGS-PV-0877-T was discovered at the Schoenstadt site, in the city of Santa Cruz do Sul (Santacruzodon Assemblage Zone, Santa Maria Formation). This specimen, consisting of disarticulated cranial elements (such as nasals, frontals, parietals, postorbitals, a left squamosal, a left pterygoid and a fragment of a right mandibular ramus that bears teeth) and postcranial elements (such as femora, the left tibia, one vertebral centrum and two rib fragments), is assigned to the ‘proterochampsian’ Chanaresuchus bonapartei Romer (1971). This assignment is based on the shared V-shaped frontal-parietal suture of the new specimen and Chanaresuchus bonapartei, which differs from the transversely aligned and zigzagged pattern of C. ischigualastensis.

First record of Colognathus (?Amniota) from the Middle Triassic of Europe

This is a short note redescribing material from the Middle Triassic of Germany that is referable to the enigmatic vertebrate taxon Colognathus, which has been considered everything from a 'fish' to and archosauromorph reptile. Unfortunately the new material does not clarify the systematic position of Colognathus, but does represent a temporal and geographic extension.

Sues, H. -D.,  and R. R. Schoch. 2013. First record of Colognathus (?Amniota) from the Middle Triassic of Europe, Journal of Vertebrate Paleontology, 33:4, 998-1002. http://dx.doi.org/10.1080/02724634.2013.732977

Chirotherium Trackways from the Middle Triassic of China

Xing, L., Klein, H., Lockley, M. G., Li, J., Zhang, J., Matsukawa, M., and J. Xiao. 2013. Chirotherium trackways from the Middle Triassic of Guizhou, China. Ichnos 20: 99-107. DOI:10.1080/10420940.2013.788505

Abstract - Triassic tetrapod footprints from China are less well known than those from the Jurassic and Cretaceous. Archosaurian trackways of the ichnogenus Chirotherium were found in the Middle Triassic Guanling Formation in Zhenfeng County (Guizhou Province) at the southwestern edge of the Yangtze plate in the early 1960s but were not correctly identified and adequately described until 40 years later. Here we give a detailed re-description and review of the trackways, which are known from two localities near the villages of Niuchang and Longchang. They occur on the bedding surface of a mud-cracked argillaceous dolostone deposited in a near-shore, shallow-water environment. Their morphology and general trackway pattern indicate that they pertain to the ichnospecies Chirotherium barthii, well known from Middle Triassic
track surfaces of Europe, North and South America, and northern Africa. A peculiarity of the trackways from China are the low pace angulation and stride length, reflecting slow-moving trackmakers, which were basal crown-group archosaurs, possibly early
representatives of the dinosaur-bird line or, alternatively, stem-group crocodylians. These tracks constitute the only chirotheriid record known from Asia thus far and indicate a Pangea-wide distribution for this ichnotaxon. Biostratigraphically, assemblages with C. barthii are characteristic of the early Anisian, an age assignment already supported for the Guanling Formation based on conodont and bivalve biostratigraphy. In contrast, however, radiometric data from an interlayered ash bed indicate a Ladinian age.

A new interpretation of material of an armored archosauriform from the Middle Triassic of Germany that solves the mystery of the purported Middle Triassic aetosaur.  Instead this specimen is from a taxon more closely to Doswellia kaltenbachi. This new taxon supports the growing realization that doswelliids had a broader range geographically and temporally.

Schoch, R. R., and H.-D. Sues. 2013. A new archosauriform reptile from the Middle Triassic (Ladinian) of Germany. Journal of Systematic Palaeontology (advance online publication) DOI:10.1080/14772019.2013.781066

Abstract- Numerous well-preserved skeletal remains of a distinctive armoured archosauriform reptile from the Lower Keuper (Erfurt Formation; Middle Triassic: Ladinian: Longobardian) of Baden-Württemberg (Germany) represent a new taxon, Jaxtasuchus salomoni gen. et sp. nov. The dermal armour of Jaxtasuchus comprises transverse rows of four rectangular osteoderms each in the cervical, dorsal and caudal regions, with the individual plates closely resembling those of Doswellia kaltenbachi from Carnian strata in North America. The long and low maxilla of Jaxtasuchus held at least 15 teeth. The labial and lingual surfaces of the tall, only slightly recurved crowns of the maxillary teeth bear distinct vertical ridges and smooth mesial and distal carinae. The cervical region of the vertebral column is long. Phylogenetic analysis places Jaxtasuchus as the sister taxon to
Doswellia in Doswelliidae sensu Desojo et al. (2011). Doswelliidae is diagnosed by the coarsely reticulate, incised ornamentation of osteoderms composed of central regular pits of subequal size and contour, and a mostly smooth anterior articular lamina on each osteoderm. The discovery of Jaxtasuchus confirms that Doswelliidae had a wide palaeogeographical distribution during the latter half of the Triassic.

Rediscovered Specimen Draws Dinosaur Origins Down Into the Middle Triassic

I've been peripherally involved in the recent renaissance regarding dinosaur origins since my discovery of the skeleton of Revueltosaurus callenderi in 2004 and the subsequent recognition that it was not a dinosaur. With my good friends and colleagues Sterling Nesbitt and Randall Irmis, I proceeded to reexamine much of the Late Triassic dinosaur record using an apomorphy-based approach emphasized by UT Austin professor Chris Bell and his colleagues for Neogene vertebrates. Our findings were that Triassic dinosaurs were actually rarer than previously believed, especially in North America. In addition, extensive fieldwork by Sterling and Randy led to the discoveries of Dromomeron romeri, Tawa hallae, and Asilisaurus kongwe, filling in some key gaps in our understanding of the early diversification of the Ornithodira.  Nonetheless it has become readily apparent that many important specimens crucial to this issue were not weathering out of outcrops in the field, but rather were sitting un- or misidentified in museum collections around the globe. Our new understanding of character states and polarities for early diverging dinosauriforms provided us with specific search criteria leading to the discoveries and/or reinterpretations of taxa such as Eucoelophysis baldwini, Dromomeron gregorii, Technosaurus smalli, Daemonosaurus chauliodus, and of course Effigia okeeffae, all from previously collected material including fossils collected for Edward Cope in the 1800s. Furthermore, Randy's work found that the rise of dinosaurs was diachronous, although the timing is still poorly understood.

The discovery of the silesaurid Asilisaurus kongwe (published in 2010) pulled the split between Silesauridae and Dinosauria into the Middle Triassic creating a significant ghost lineage for Dinosauria as the earliest known bona fide dinosaurs do not appear until the end of the Carnian stage of the Late Triassic. Amazingly it appears that we did not need to wait very long for this ghost lineage to be filled.

Today's issue of Biology Letters has a paper by Sterling Nesbitt, Paul Barrett, Sarah Werning, Christian Sidor, and the late Alan Charig on a probable new dinosaur from the Middle Triassic of Tanzania. Even more amazing is that this is not a new specimen, but was actually collected in the 1930s, and never described, except in Charig's 1950s dissertation, until today. Charig named the new specimen Nyasasaurus parringtoni and until now this name has been a nomen nudum.

Known from a partial humerus and several vertebrate (three cervical, five presacral and three sacral), reanalysis places Nyasasaurus as either a dinosaur or as the sister taxon to Dinosauria. The humerus bears a ventrally elongated deltopectoral crest with a deflected apex, both synapomorphies of Dinosauria. The cervical vertebrae are elongate and possess deep lateral fossae, consistent with character states found in dinosaurs. The presence of three sacral vertebrae, although not restricted to Dinosauria, also supports this placement. This interpretation is supported not only by a phylogenetic analysis but also by bone histology, which shows high, continuous growth rates similar to that of early diverging dinosaurs. 

This material suggests that dinosaurs probably appeared in the fossil record 10 to 15 million years earlier than we expected. Furthermore, Nesbitt et al. argue that this strongly supports the hypothesis that dinosaurs were not a dominant group during their early history. Finally, Nyasasaurus also provides more support for a Gondwanan origin of dinosaurs.

One thing that is now definitely clear is that workers interested in dinosaur origins will need to spend more time in Middle Triassic terrestrial units. Back in 2004 I don't think any of us fathomed what discoveries and interpretations the next decade would bring. As I often state, it is not necessarily what we already know that dirves our work, but what is still out there for us to learn.

Nesbitt, S. J., Barrett, P. M., Werning, S., Sidor, C. A., and A. J. Charig. 2012. The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania. Biology Letters.
 

Abstract - The rise of dinosaurs was a major event in vertebrate history, but the timing of the origin and early diversification of the group remain poorly constrained. Here, we describe Nyasasaurus parringtoni gen. et sp. nov., which is identified as either the earliest known member of, or the sister-taxon to, Dinosauria. Nyasasaurus possesses a unique combination of dinosaur character states and an elevated growth rate similar to that of definitive early dinosaurs. It demonstrates that the initial dinosaur radiation occurred over a longer timescale than previously thought (possibly 15 My earlier), and that dinosaurs and their immediate relatives are better understood as part of a larger Middle Triassic archosauriform radiation. The African provenance of Nyasasaurus supports a southern Pangaean origin for Dinosauria.

Redescription of the Archosaur Parringtonia gracilis from the Middle Triassic Manda Beds of Tanzania

Here is another redescription of another of the enigmatic archosauriforms from the Middle Triassic Manda Formation. This study confirms the affinity of Parringtonia gracilis and Erpetosuchus granti, and reinforces the importance of redescribing these older taxa using an apomorphy-based approach and placing them in a modern phylogenetic analysis. Unfortunately the exact position of Erpetosuchidae with Archosauria was not able to be precisely determined.

Nesbitt, S. J., and R. J. Butler. 2012. Redescription of the archosaur Parringtonia gracilis from the Middle Triassic Manda beds of Tanzania, and the antiquity of Erpetosuchidae. Geological Magazine (FirstView article), 14p. doi:10.1017/S0016756812000362 

Abstract - Parringtonia gracilis Huene, 1939 is represented by both cranial and postcranial material collected from the lower Middle Triassic (Anisian) Lifua Member of the Manda beds in southwestern Tanzania. This aberrant taxon was previously proposed to have affinities with pseudosuchian archosaurs, and specifically with the enigmatic Erpetosuchus granti from the Upper Triassic of Scotland. Here, we confirm the close affinities of Parringtonia gracilis and Erpetosuchus granti based on the following unambiguous synapomorphies: mediolaterally expanded posterior portion of the maxilla, alveoli present only in the anterior half of the maxilla, and absence of tooth serrations. Furthermore, the two taxa share osteoderms with deep sculpturing, a deep fossa on the dorsal margin of the neural spines and a heavily waisted shaft of the scapula. We added both Parringtonia gracilis and Erpetosuchus granti into a comprehensive phylogenetic analysis of early archosaurs and found that these taxa are clearly referable to Archosauria but that relationships are poorly resolved at the base of this clade. However, our analysis demonstrates that Erpetosuchus granti is not closely related to Crocodylomorpha, as has been hypothesized previously. The Erpetosuchidae are a clade of small-bodied archosaurs that have a poor fossil record but have members from both northern and southern Pangaea, ranging temporally from the Middle to Late Triassic. Thus, Erpetosuchidae is part of the early archosaurian radiation.

Diandongos​uchus, A New Archosaur from Triassic of China

There are lots of incredible specimens coming out of the Middle Triassic in recent years (SVP attendees will see another in a talk this year by Sterling Nesbitt and colleagues), and this amazing fossil from the Ladinian of China does not disappoint. It consists of most of a partially articulated/associated skeleton found in marine sediments not far from where the early diverging poposauroid  Qianosuchus mixtus was  recovered some time ago.

The authors have provided color figures that allow the reader to see many of the details of the skeleton; however, the semi-articulated nature of the specimen seems to prelude dismantling of the specimen to see three dimensional views of the specimen. Furthermore, because it is in a marine shale, some crushing of the specimen has occurred. This is unfortunate because it does not allow clear study of the ilia or of the ends of the femora, which would provide key characters for the taxonomic placement of the specimen. Li et al. do code the specimen into Sterling Nesbitt's recent (2011) phylogenetic matrix of Archosauriformes and it is recovered, with much support, as the earliest diverging poposauroid. This is of interest of course because it suggests that the plesiomorphic conditions for poposauroids are quadrupedal, toothed, long-snouted forms that lack an expanded dorsal sail, possess osteoderms, and are possibly semi-aquatic. Compare this to other members of the clade such as Effigia okeeffae. The amount of morphological variation in this group is incredible.

I'll admit that I'm not entirely convinced of the phylogenetic placement of this specimen, but unfortunately I cannot get into the details of why at this time. Let's just say that this is an extremely interesting taxon that should be the subject of debate for a while to come. I do really wish the ilia were better preserved or more visible, but it is really hard to complain about such a beautiful fossil.

Li, C., Wu, X.-C., Zhao, L.-J., Sato, T. and L.-T. Wang. 2012. A new archosaur (Diapsida, Archosauriformes) from the marine Triassic of China. Journal of Vertebrate Paleontology 32(5): 1064-1081. DOI:10.1080/02724634.2012.694383http://www.tandfonline.com/doi/abs/10.1080/02724634.2012.694383

Abstract - A new Middle Triassic archosaur, Diandongosuchus fuyuanensis, gen. et
sp. nov., is described on the basis of a skeleton from the Zhuganpo Member (Ladinian) of the Falang Formation, eastern Yunnan Province, China. It is primarily characterized by the nasal process of the premaxilla extending posteriorly well beyond the external naris, the super-sized coracoid foramen laterally bordered by the scapula, the ischium with a strongly expanded medial portion anteroposteriorly longer than the proximodistal height of the bone, and anteriorly notched cervical osteoderms. D. fuyuanensis is a pseudosuchian on the basis of the crocodile-normal tarsal joint and other features, such as the distal end of the ulna in posterolateral view squared off, osteoderms with a distinct anterior process, the presacral vertebrae dorsally covered by more than one osteoderm, dorsal osteoderm alignment dorsal to presacrals 10–24 staggered, the pubis-ischium contact reduced to a thin proximal contact, and the medial contact of the ischia extensive but the dorsal margins separate. It is from a marine deposit but shows few morphological adaptations of the postcranial skeleton for a semiaquatic way of life when compared with Qianosuchus from the Anisian limestone of the same area. A phylogenetic analysis derived from an existing data matrix suggests that the new archosaur occupies the basal-most position in Poposauroidea and further confirms the poposauroid status of Qianosuchus. On the basis of current information, the discovery of Diandongosuchus does not firmly underscore the affinity of the semiterrestrial vertebrate faunas between the eastern and western regions along the northern coastline of the Tethys.

New Ladinian Biostratigraphic Correlation Between South America and South Africa

Nice biostratigraphic correlation between the Santa Maria Formation of Brazil and the Karoo of South Africa. Partially fills the 'Ladinian Gap' in the Karoo.

Abdala, F., Marsicano, C. A., Smith, R. M. H., and R. Swart. 2012. Strengthening western Gondwanan correlations: a Brazilian dicynodont (Synapsida, Anomodontia) in the Middle Triassic of Namibia. Gondwana Research (advance online publication)
http://dx.doi.org/10.1016/j.gr.2012.07.011

Abstract - Terrestrial Middle Triassic strata occur throughout continental Africa, and are particularly well exposed in South Africa, Tanzania, Zambia, and Namibia. The youngest age for all these African deposits is widely accepted as early Middle Triassic (Anisian). Fossils collected recently from the uppermost strata of the upper Omingonde Formation in Namibia highlighted the presence of Chiniquodon, a carnivorous cynodont previously only found in Ladinian-Carnian aged rocks of South America. In addition, work in progress indicates that a large archosaur, originally reported as Erythrosuchus, also discovered from levels close to the top of this unit, is in fact a rauisuchian, a group of archosaurs well known from Ladinian-Carnian beds of southern South America. Here we present the first record of the tuskless dicynodont Stahleckeria potens, from the top of the upper Omingonde Formation in central Namibia. This taxon was up until now only known from the Ladinian Dinodontosaurus Assemblage Zone of the Santa Maria Formation in southern Brazil. Thus, compelling evidence for a Ladinian age for the upper levels of the upper Omingonde Formation is provided by two therapsid and one archosaur taxa. The tetrapod fauna of the upper Omingonde Formation partially fills the gap of the well-documented hiatus (Ladinian gap), prevalent throughout the Karoo basins of south and central Africa. The presence of the same therapsid taxa in the Namibian Waterberg Basin and the Paraná Basin of Brazil during Middle Triassic suggests that these basins were biogeographically linked through a series of interconnecting lowlands, with no major ecological, climatic and/or physical barriers.

New U-Pb Dates for the Middle Triassic of Monte San Giorgio

Stockar, R., Baumgartner, P. O., and D. Condon. 2012. Integrated Ladinian bio-chronostratigraphy and geochrononology of Monte San Giorgio (Southern Alps, Switzerland). Swiss Journal of Geosciences 105:85-108.
Abstract - New biostratigraphic data significantly improve the age assignment of the Ladinian succession of Monte San Giorgio (UNESCO World Heritage List site, Southern Alps, Switzerland), whose world-famous fossil marine vertebrate faunas are now dated to the substage and zone levels. High-resolution single-zircon U–Pb dating was performed using ID-TIMS and chemical abrasion (CA) pre-treatment technique on volcanic ash layers intercalated in the biostratigraphically-defined intervals of the Meride Limestone. It yielded ages of 241.07 ± 0.13 Ma (Cava superiore beds, P. gredleri Zone), 240.63 ± 0.13 Ma (Cassina beds, P gredleri/P. archelaus transition Zone) and 239.51 ± 0.15 Ma (Lower Kalkschieferzone, P. archelaus Zone). Our results suggest that the time interval including the vertebrate-bearing Middle Triassic section spans around 4 Myr and is thus significantly shorter than so far assumed. The San Giorgio Dolomite and the Meride Limestone correlate with intervals of the Buchenstein Formation and the Wengen Formation in the reference section at Bagolino, where the Global boundary Stratotype Section and Point (GSSP) for the base of the Ladinian was defined. The new radio-isotopic ages of the Meride Limestone are up to 2 Myr older than those published for the biostratigraphically-equivalent intervals at Bagolino but they are consistent with the recent re-dating of the underlying Besano Formation, also performed using the CA technique. Average sedimentation rates at Monte San Giorgio are by more than an order of magnitude higher compared to those assumed for the Buchenstein Formation, which formed under sediment starved pelagic conditions, and reflect prevailing high subsidence and high carbonate mud supply from the adjoining Salvatore/Esino platforms.  Finally, the high-resolution U–Pb ages allow a correlation of the vertebrate faunas of the Cava superiore/Cava inferior beds with the marine vertebrate record of the Prosanto Formation (Upper Austroalpine), so far precluded by the poor biostratigraphic control of the latter.

Largocephalosaurus, a New Eosauropterygian from the Middle Triassic of China

Cheng, L., Chen, X., Zeng, X., and Y. Cai. 2012. A new eosauropterygian (Diapsida: Sauropterygia) from the Middle Triassic of Luoping, Yunnan Province. Journal of Earth Science 23:33-40. DOI: 10.1007/s12583-012-0231-z

Abstract - A new eosauropterygian, Largocephalosaurus polycarpon gen. et sp. nov., was described based on a skeleton from the Middle Triassic of Luoping, Yunnan Province, southwestern China. The new taxon is characterized by a big skull, paired frontal, laterally expanded upper temporal fossa, anterior process of squamosal entering orbit, robust teeth with basally expanded crown and blunt tip, short cervical region, distinctly elongated transverse process of the dorsal vertebrae, short and broad dorsal ribs, stout gastralia, scapula with distinctly posterodorsally extending blade, distinctly robust humerus, eleven carpal ossifications, and a manual fomula of 2-3-4-5-5. A phylogenetic analysis suggests that Largocephalosaurus is the basal-most member of a clade including Wumengosaurus, European pachypleurosaurs, and Nothosauroidea.

Two New Triassic Temnospondyl Papers in the Journal Palaeontology

Witzmann, F., Schoch, R. R., Hilger, A., and N. Kardjilov. 2012. Braincase, palatoquadrate and ear region of the plagiosaurid Gerrothorax pulcherrimus from the Middle Triassic of Germany. Palaeontology 55:31-50. DOI: 10.1111/j.1475-4983.2011.01116.x

Abstract - The complete neurocranium plus palatoquadrate of the plagiosaurid temnospondyl Gerrothorax pulcherrimus from the Middle Triassic of Germany is described for the first time, based on outer morphological observations and micro-CT scanning. The exoccipitals are strong elements with paroccipital processes and well-separated occipital condyles. Anterolaterally, the exoccipitals contact the otics, which are mediolaterally elongated and have massive lateral walls. The otics contact the basisphenoid, which shows well-developed sellar processes. Anteriorly, the basisphenoid is continuous with the sphenethmoid region. In its posterior portion, the sphenethmoid gives rise to robust, laterally directed laterosphenoid walls, a unique morphology among basal tetrapods. The palatoquadrate is extensively ossified. The quadrate portion overlaps the descending lamina of squamosal and ascending lamina of pterygoid anteriorly, almost contacting the epipterygoid laterally. The epipterygoid is a complex element and may be co-ossified with otics and laterosphenoid walls. It has a broad, sheet-like footplate and a horizontally aligned ascending process that contacts the laterosphenoid walls. The degree of ossification of the epipterygoid, however, is subject to individual variation obviously independent from ontogenetic changes. The stapes of Gerrothorax is a large, blade-like element that differs conspicuously from the plesiomorphic temnospondyl condition. It has a prominent anterolateral projection which has not been observed in other basal tetrapods. Morphology of neurocranium and palatoquadratum of Gerrothorax most closely resembles that of the Russian plagiosaurid Plagiosternum danilovi, although the elements are less ossified in the latter. The extensive endocranial ossification of Gerrothorax is consistent with the general high degree of ossification in the exo- and endoskeleton of this temnospondyl and supports the view that a strong endocranial ossification cannot be evaluated as a plesiomorphic character in basal tetrapods.

Dias-da-Silva, S., Sengupta, D. P., Cabriera, S. F., and L. R. Da Silva. 2012. The presence of Compsocerops (Brachyopoidea: Chigutisauridae) (Late Triassic) in southern Brazil with comments on chigutisaurid palaeobiogeography. Palaeontology 55:163-172. DOI: 10.1111/j.1475-4983.2011.01120.x

Abstract - Chigutisauridae is the longest-lived trematosaurian clade (from early Triassic to early Cretaceous). They were reported in Argentina, Australia, India and South Africa. This contribution reports a putative chigutisaurid specimen in the Carnian of southern Brazil (Santa Maria Formation, Paraná Basin). The material comprises two skull fragments, a mandibular fragment, a clavicular blade and a humerus. Ontogenetic features point to an early development stage of the specimen. The presence of a long, straight and pointed tabular horn, which runs parallel to the skull midline towards its tip, and a distinctive projection in the posterior border of the postparietal indicates a close relationship of the Brazilian chigutisaurid with the Indian Compsocerops cosgriffi. Three distinctive and combined characters suggest that the Brazilian chigutisaurid is a distinctive specimen: the presence of an alar process of the jugal in the ventral margin of the orbit; jugal does not extend well beyond the anterior margin of the orbit; and tabular does not contact the parietal. These characters could justify the erection of a new taxon; however, they might reflect its immature ontogenetic stage as well. Accordingly, we attribute this new specimen to Compsocerops sp. Argentinean and Indian occurrences are dated as Norian, so the presence of a Carnian chigutisaurid in southern Brazil indicates that western Gondwana chigutisaurids have first occupied the Paraná Basin and later migrated towards west (to Argentina) and east (India). However, the presence of ghost chigutisaurid taxa cannot be dismissed, because their long temporal range contrasts with their still short (in comparison with other temnospondyl groups) geographic distribution. Hence, they might have been more geographically widespread than their fossil record suggests.