scholarly journals The anatomy and phylogenetic position of the erythrosuchid archosauriform Guchengosuchus shiguaiensis from the earliest Middle Triassic of China

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6435 ◽  
Author(s):  
Richard J. Butler ◽  
Martín D. Ezcurra ◽  
Jun Liu ◽  
Roland B. Sookias ◽  
Corwin Sullivan
Keyword(s):  
Phylogenetic Analysis ◽  
Mass Extinction ◽  
Middle Triassic ◽  
Lower Triassic ◽  
Shaanxi Province ◽  
Phylogenetic Position ◽  
Apex Predators ◽  
Worldwide Distribution ◽  
Fossil Material ◽  
Anatomical Information

Erythrosuchidae is a clade of early archosauriform reptiles, which were apex predators in many late Early and Middle Triassic ecosystems, following the Permo-Triassic mass extinction. Erythrosuchids had a worldwide distribution, with well-preserved fossil material known from South Africa, European Russia, and China. We here redescribe the anatomy and revise the taxonomy of Guchengosuchus shiguaiensis, which is one of the stratigraphically oldest erythrosuchids and is known from a single partial skeleton from the lowermost Middle Triassic (lower Anisian) lower Ermaying Formation of Shaanxi Province, China. We provide a new differential diagnosis for Guchengosuchus shiguaiensis, and identify a series of autapomorphies relating to the morphologies of the skull roof and vertebrae. Incorporating updated anatomical information for Guchengosuchus into the most comprehensive morphological phylogenetic analysis available for early archosauromorphs recovers it as an early branching member of Erythrosuchidae, outside of the clade formed by Garjainia, Erythrosuchus, Chalishevia, and Shansisuchus. Fugusuchus hejiapanensis, from the uppermost Lower Triassic to lower Middle Triassic Heshanggou Formation of China, is recovered as the earliest branching member of Erythrosuchidae.

scholarly journals A reappraisal of the Middle Triassic chirotheriid Chirotherium ibericus Navás, 1906 (Iberian Range NE Spain), with comments on the Triassic tetrapod track biochronology of the Iberian Peninsula

2015 ◽  
Author(s):  
Ignacio Díaz-Martínez ◽  
Diego Castanera ◽  
José Manuel J.M. Gasca ◽  
José Ignacio Canudo
Keyword(s):  
Iberian Peninsula ◽  
Middle Triassic ◽  
Lower Triassic ◽  
Upper Triassic ◽  
Worldwide Distribution ◽  
Track Record ◽  
Iberian Range ◽  
Vertebrate Tracks ◽  
The 19Th Century ◽  
Stratigraphic Range

Triassic vertebrate tracks are known from the beginning of the 19th century and have a worldwide distribution. Several Triassic track ichnoassemblages and ichnotaxa have a restricted stratigraphic range and are useful in biochronology and biostratigraphy. The record of Triassic tracks in the Iberian Peninsula has gone almost unnoticed although more than 25 localities have been described since 1897. In one of these localities, the naturalist Longinos Navás described the ichnotaxon Chirotherium ibericus in 1906.The vertebrate tracks are in two sandy slabs from the Anisian (Middle Triassic) of the Moncayo massif (Zaragoza, Spain). In a recent revision, new, previously undescribed vertebrate tracks have been identified. The tracks considered to be C. ibericus as well as other tracks with the same morphology from both slabs have been classified as Chirotherium barthii. The rest of the tracks have been assigned to Chirotheriidae indet., Rhynchosauroides isp. and undetermined material. This new identification of C. barthii at the Navás site adds new data to the Iberian record of this ichnotaxon, which is characterized by the small size of the tracks when compared with the main occurrences of this ichnotaxon elsewhere. As at the Navás tracksite, the Anisian C. barthii-Rhynchosauroides ichnoassemblage has been found in other coeval localities in Iberia and worldwide. This ichnoassemblage belongs to the upper Olenekian-lower Anisian interval according to previous biochronological proposals. Analysis of the Triassic Iberian record of tetrapod tracks is uneven in terms of abundance over time. From the earliest Triassic to the latest Lower Triassic the record is very scarce, with Rhynchosauroides being the only known ichnotaxon. Rhynchosauroides covers a wide temporal range and gives poor information for biochronology. The record from the uppermost Lower Triassic to the Middle Triassic is abundant. The highest ichnodiversity has been reported for the Anisian with an assemblage composed of Dicynodontipus, Procolophonichnium, Rhynchosauroides, Rotodactylus, Chirotherium, Isochirotherium, Coelurosaurichnus and Paratrisauropus. The Iberian track record from the Anisian is coherent with the global biochronology proposed for Triassic tetrapod tracks. Nevertheless, the scarcity of track occurrences during the late Olenekian and Ladinian prevents analysis of the corresponding biochrons. Finally, although the Iberian record for the Upper Triassic is not abundant, the presence of Eubrontes, Anchisauripus and probably Brachychirotherium is coherent with the global track biochronology as well. Thus, the Triassic track record in the Iberian Peninsula matches the expected record for this age on the basis of a global biochronological approach, supporting the idea that vertebrate Triassic tracks are a useful tool in biochronology.

A sail-backed suchian from the Heshanggou Formation (Early Triassic: Olenekian) of China

2010 ◽  
Vol 101 (3-4) ◽  
pp. 271-284 ◽  
Author(s):  
Sterling J. Nesbitt ◽  
Jun Liu ◽  
Chun Li
Keyword(s):  
Phylogenetic Analysis ◽  
Middle Triassic ◽  
Central China ◽  
Phylogenetic Position ◽  
Early Triassic ◽  
Temporal Constraints ◽  
Crown Group ◽  
North Central ◽  
Partial Skeleton ◽  
Common Components

ABSTRACTThe two major lineages of extant archosaurs, crocodylians and avians, diverged in the Triassic, but the details and timing of this event are incompletely understood. Fragmentary and phylogenetically uninformative specimens, in addition to poor temporal constraints on rock units from the Early and Middle Triassic, typify obstacles in identifying early archosaurs. This paper re-describes the partial skeleton of the only known specimen of Xilousuchus sapingensis Wu, 1981 from the Early Triassic Heshanggou Formation in north-central China. Originally assigned to the non-archosaurian archosauriform clade Proterosuchidae, an extensive phylogenetic analysis posits X. sapingensis as a crown-group archosaur within Suchia, thus making this taxon the unequivocally oldest known member of Archosauria. The age and phylogenetic position of X. sapingensis indicate that many archosaurs, including all major clades of non-archosaurian archosauriforms, the avianline, ornithosuchids, aetosaurs and paracrocodylomorph lineages, must have diverged by the end of the Early Triassic. X. sapingensis is part of a possible clade of sail-backed poposauroids that were common components of archosaur assemblages during the Early to Middle Triassic.

Palicella, a new genus of lichenized fungi and its phylogenetic position within Lecanoraceae

2014 ◽  
Vol 46 (4) ◽  
pp. 535-552 ◽  
Author(s):  
Pamela RODRIGUEZ FLAKUS ◽  
Christian PRINTZEN
Keyword(s):  
Phylogenetic Analysis ◽  
Phylogenetic Trees ◽  
New Genus ◽  
Usnic Acid ◽  
Phylogenetic Position ◽  
New Combinations ◽  
Monophyletic Clade ◽  
Closely Related Species ◽  
Worldwide Distribution ◽  
Molecular Phylogenetic

AbstractNon-saxicolous lecideoid lichens form a diverse and polyphyletic group of species with a worldwide distribution. The phylogenetic relationships of the taxa and major clades are still largely unresolved. Here we introduce a new genus Palicella Rodr. Flakus & Printzen for Lecidea glaucopa Hook. f. & Tayl. and two closely related species. Our molecular phylogenetic results, based on maximum likelihood and Bayesian phylogenetic trees, and a combined dataset of five gene loci (ITS, nrLSU, mrSSU, RPB1 and RPB2), indicate that Palicella forms a monophyletic clade sister to Lecanora symmicta and Pyrrhospora quernea. The new genus is characterized by biatorine apothecia, which are often darkened (by the pigment Cinereorufa-green), an exciple of radiating, narrow hyphae with strongly elongate lumina, a hymenium with branched and sparsely anastomosed paraphyses, an ascus with a broad axial body surrounded by a distinct darker staining layer, and narrowly ellipsoid ascospores. Atranorin is present in all, usnic acid in two and pannarin in one species of the genus. Three new combinations are proposed: Palicella filamentosa (Stirt.) Rodr. Flakus & Printzen, P. glaucopa (Hook. f. & Taylor) Rodr. Flakus & Printzen, and P. schizochromatica (Pérez-Ortega, T. Sprib. & Printzen) Rodr. Flakus & Printzen. The molecular phylogenetic analysis confirms that Lecidea hercynica Hauck & Schmull is a synonym of P. filamentosa. An identification key to the species is provided.

scholarly journals A reappraisal of the Middle Triassic chirotheriid Chirotherium ibericus Navás, 1906 (Iberian Range NE Spain), with comments on the Triassic tetrapod track biochronology of the Iberian Peninsula

2015 ◽  
Author(s):  
Ignacio Díaz-Martínez ◽  
Diego Castanera ◽  
José Manuel J.M. Gasca ◽  
José Ignacio Canudo
Keyword(s):  
Iberian Peninsula ◽  
Middle Triassic ◽  
Lower Triassic ◽  
Upper Triassic ◽  
Worldwide Distribution ◽  
Track Record ◽  
Iberian Range ◽  
Vertebrate Tracks ◽  
The 19Th Century ◽  
Stratigraphic Range

Triassic vertebrate tracks are known from the beginning of the 19th century and have a worldwide distribution. Several Triassic track ichnoassemblages and ichnotaxa have a restricted stratigraphic range and are useful in biochronology and biostratigraphy. The record of Triassic tracks in the Iberian Peninsula has gone almost unnoticed although more than 25 localities have been described since 1897. In one of these localities, the naturalist Longinos Navás described the ichnotaxon Chirotherium ibericus in 1906.The vertebrate tracks are in two sandy slabs from the Anisian (Middle Triassic) of the Moncayo massif (Zaragoza, Spain). In a recent revision, new, previously undescribed vertebrate tracks have been identified. The tracks considered to be C. ibericus as well as other tracks with the same morphology from both slabs have been classified as Chirotherium barthii. The rest of the tracks have been assigned to Chirotheriidae indet., Rhynchosauroides isp. and undetermined material. This new identification of C. barthii at the Navás site adds new data to the Iberian record of this ichnotaxon, which is characterized by the small size of the tracks when compared with the main occurrences of this ichnotaxon elsewhere. As at the Navás tracksite, the Anisian C. barthii-Rhynchosauroides ichnoassemblage has been found in other coeval localities in Iberia and worldwide. This ichnoassemblage belongs to the upper Olenekian-lower Anisian interval according to previous biochronological proposals. Analysis of the Triassic Iberian record of tetrapod tracks is uneven in terms of abundance over time. From the earliest Triassic to the latest Lower Triassic the record is very scarce, with Rhynchosauroides being the only known ichnotaxon. Rhynchosauroides covers a wide temporal range and gives poor information for biochronology. The record from the uppermost Lower Triassic to the Middle Triassic is abundant. The highest ichnodiversity has been reported for the Anisian with an assemblage composed of Dicynodontipus, Procolophonichnium, Rhynchosauroides, Rotodactylus, Chirotherium, Isochirotherium, Coelurosaurichnus and Paratrisauropus. The Iberian track record from the Anisian is coherent with the global biochronology proposed for Triassic tetrapod tracks. Nevertheless, the scarcity of track occurrences during the late Olenekian and Ladinian prevents analysis of the corresponding biochrons. Finally, although the Iberian record for the Upper Triassic is not abundant, the presence of Eubrontes, Anchisauripus and probably Brachychirotherium is coherent with the global track biochronology as well. Thus, the Triassic track record in the Iberian Peninsula matches the expected record for this age on the basis of a global biochronological approach, supporting the idea that vertebrate Triassic tracks are a useful tool in biochronology.

The postcranial skeleton, phylogenetic position, and probable lifestyle of the Early Triassic reptile Procolophon trigoniceps

2003 ◽  
Vol 40 (4) ◽  
pp. 527-556 ◽  
Author(s):  
Michael deBraga
Keyword(s):  
South Africa ◽  
Morphological Study ◽  
Lower Triassic ◽  
Sister Group ◽  
Phylogenetic Position ◽  
Sister Group Relationship ◽  
Early Triassic ◽  
Postcranial Skeleton ◽  
Sister Clade ◽  
Key Innovations

A morphological study of the postcranial skeleton of Procolophon trigoniceps from the Lower Triassic of South Africa and Antarctica is undertaken. Procolophon shares a sister-group relationship with the procolophonid Tichvinskia from the Lower Triassic of Russia and is a basal member of Procolophonidae. This clade also includes the enigmatic taxon Sclerosaurus, believed most recently to be a pareiasaur relative. Owenettids form a separate lineage from Procolophonidae and are predominantly restricted to the Permian of both South Africa and Madagascar. A phylogenetically based assessment is considered, in which specialized modern taxa (sand lizards) are compared to their nonfossorial sister clade, allowing for "key innovations" to be identified. A similar comparison between owenettids and procolophonids reveals a number of apparent "key innovations" within procolophonids that are suggestive of a burrowing lifestyle for Procolophon.

Early and Middle Triassic trends in diversity, evenness, and size of foraminifers on a carbonate platform in south China: implications for tempo and mode of biotic recovery from the end-Permian mass extinction

Paleobiology ◽  
2011 ◽  
Vol 37 (3) ◽  
pp. 409-425 ◽  
Author(s):  
Jonathan L. Payne ◽  
Mindi Summers ◽  
Brianna L. Rego ◽  
Demir Altiner ◽  
Jiayong Wei ◽  
...  
Keyword(s):  
South China ◽  
Mass Extinction ◽  
Evolutionary Dynamics ◽  
Middle Triassic ◽  
Carbonate Platform ◽  
Early Triassic ◽  
Data Set ◽  
Recovery Pattern ◽  
Biotic Recovery ◽  
Permian Mass Extinction

Delayed biotic recovery from the end-Permian mass extinction has long been interpreted to result from environmental inhibition. Recently, evidence of more rapid recovery has begun to emerge, suggesting the role of environmental inhibition was previously overestimated. However, there have been few high-resolution taxonomic and ecological studies spanning the full Early and Middle Triassic recovery interval, leaving the precise pattern of recovery and underlying mechanisms poorly constrained. In this study, we document Early and Middle Triassic trends in taxonomic diversity, assemblage evenness, and size distribution of benthic foraminifers on an exceptionally exposed carbonate platform in south China. We observe gradual increases in all metrics through Early Triassic and earliest Middle Triassic time, with stable values reached early in the Anisian. There is little support in our data set for a substantial Early Triassic lag interval during the recovery of foraminifers or for a stepwise recovery pattern. The recovery pattern of foraminifers on the GBG corresponds well with available global data for this taxon and appears to parallel that of many benthic invertebrate clades. Early Triassic diversity increase in foraminifers was more gradual than in ammonoids and conodonts. However, foraminifers continued to increase in diversity, size, and evenness into Middle Triassic time, whereas diversity of ammonoids and conodonts declined. These contrasts suggest decoupling of recovery between benthic and pelagic environments; it is unclear whether these discrepancies reflect inherent contrasts in their evolutionary dynamics or the differential impact of Early Triassic ocean anoxia or associated environmental parameters on benthic ecosystems.

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