Late Triassic megalodontids (Bivalvia) from the headwaters of the Yangtze River, Qinghai province, west China

2007 ◽  
Vol 81 (6) ◽  
pp. 1327-1347 ◽  
Author(s):  
Huazhou Yao ◽  
Renjie Zhang ◽  
John Pojeta ◽  
Jinggen Sha ◽  
Jianxiong Wang

A bivalve faunule of six species is described from the Upper Triassic Jiapila Formation at the headwaters of the Yangtze River, southern Qinghai, China. The new species, Neomegalodon cornutus and Quemocuomegalodon circularis, are described. The type species of Quemocuomegalodon, Q. orientus, is revised. Quemocuomegalodon orientus Yao, Sha, and Zhang (2003) is now known from abundant, well-preserved specimens that show great variation in shape, size, thickness of shell, and dentition, and the species Q. longitatus, Yao, Sha, and Zhang (2003) is now placed in synonymy with Q. orientus. There are significant morphologic differences between the external appearance of shelled specimens and the internal molds of species of Quemocuomegalodon. This suggests the need for the re-evaluation of many megalodontid species from elsewhere that are known only from internal molds.

2013 ◽  
Vol 87 (5) ◽  
pp. 934-964 ◽  
Author(s):  
Ewa Roniewicz ◽  
George D. Stanley

Late Carnian–early Norian corals from the Luning and Osobb formations in west-central Nevada represent an important Late Triassic fauna for understanding the paleoecology and the paleogeography of the eastern Panthalassa region during Late Triassic time. The corals occur in bedded limestone representing biostromes and patch reefs and their composition presages the important global changeover of faunas of the intra-Norian interval. A taxonomic analysis of over 60 specimens reveals a majority of colonial corals ranging from cerioid, astreoid (i.e., cerioid-plocoid lacking walls), meandroid and thamnasterioid types. Surprisingly, remnants of the original aragonite microstructure remain in some specimens, allowing a better comparison with more remote Tethyan corals. In total, 14 genera have been identified from Nevada while two genera remain undetermined. The fauna is composed of species considered typical of both the North American Cordillera and cratonal South America. The following genera and species are new and endemic to the Americas:Khytrastrea silberlingiandK. cuifiamorpha,Flexastrea serialis,Nevadoseris punctata,Areaseris nevadaensisand a new genusMinasteria(withAstrocoenia shastensisSmith, 1927 as type species). Likewise are the new species:Margarogyra silberlingiandCurtoseris dunlapcanyonae. GeneraMeandrovolzeia,Margarogyra,Ceriostella,Ampakabastraea,Retiophyllia,Distichomeandra,Curtoseris,ThamnasteriaandAstraeomorphaprovide important links to the former Tethys province. The revised coral fauna changes previous views of the close taxonomic similarity with the Tethys, instead producing a paleogeographic pattern emphasizing a much greater degree of endemism. This pattern emphasizes the isolation of Nevada from the Tethys and the similarities with some outboard terranes of the Cordillera.


2009 ◽  
Vol 83 (5) ◽  
pp. 783-793 ◽  
Author(s):  
B. Senowbari-Daryan ◽  
G. D. Stanley

Stromatomorpha californica Smith is a massive, calcified, tropical to subtropical organism of the Late Triassic that produced small biostromes and contributed in building some reefs. It comes from the displaced terranes of Cordilleran North America (Eastern Klamath terrane, Alexander terrane, and Wrangellia). This shallow-water organism formed small laminar masses and sometimes patch reefs. It was first referred to the order Spongiomorphidae but was considered to be a coral. Other affinities that have been proposed include hydrozoan, stomatoporoid, sclerosponge, and chambered sponge. Part of the problem was diagenesis that resulted in dissolution of the siliceous spicules and/or replaced them with calcite. Well-preserved dendroclone spicules found during study of newly discovered specimens necessitate an assignment of Stromatomorpha californica to the demosponge order Orchocladina Rauff. Restudy of examples from the Northern Calcareous Alps extends the distribution of this species to the Tethys, where it was an important secondary framework builder in Upper Triassic (Norian-Rhaetian) reef complexes. Revisions of Stromatomorpha californica produce much wider pantropical distribution, mirroring paleogeographic patterns revealed for other tropical Triassic taxa. Review of Liassic material from the Jurassic of Morocco, previously assigned to Stromatomorpha californica Smith var. columnaris Le Maitre, cannot be sustained. Species previously included in Stromatomorpha are: S. stylifera Frech (type species, Rhaetian), S. actinostromoides Boiko (Norian), S. californica Smith (Norian), S. concescui Balters (Ladinian-Carnian), S. pamirica Boiko (Norian), S. rhaetica Kühn (Rhaetian), S. stromatoporoides Frech, and S. tenuiramosa Boiko (Norian). Stromatomorpha rhaetica Kühn described from the Rhaetian of Vorarlberg, Austria shows no major difference from S. californica. An example described as S. oncescui Balters from the Ladinian-Carnian of the Rarau Mountains, Romania, is very similar to S. californica in exhibiting similar spicule types. However, because of the greater distance between individual pillars, horizontal layers, and the older age, S. oncescui is retained as a separate species. The net-like and regular skeleton of Spongiomorpha sanpozanensis Yabe and Sugiyama, from the Upper Triassic of Sambosan (Tosa, Japan), suggests a closer alliance with Stromatomorpha, and this taxon possibly could be the same as S. californica.


2020 ◽  
pp. 1-18
Author(s):  
Mohd Shafi Bhat ◽  
Sanghamitra Ray ◽  
P. M. Datta

Abstract The Upper Triassic Tiki Formation of India has yielded several new cynodont taxa, which are described on the basis of multiple isolated teeth and a jaw fragment. A new species of dromatheriid, Rewaconodon indicus, is defined by a tri- and tetracuspid asymmetric crown, long anterior edge of the major cusp a, cingular cusps d and f, and marked constriction at the crown-root junction. Another new dromatheriid, Inditherium floris n. gen. n. sp., is characterized by a broad, flower-shaped pentacuspid crown, multiple cingular cusps, and a weak lingual cingulum is also described from the same horizon. In addition, a new mammaliamorph taxon, Tikiodon cromptoni n. gen. n. sp., is established on a tooth specimen, which has a shovel-shaped crown, three closely spaced main cusps, a pronounced lingual cingulum with multiple cingular cusps, and a root of incomplete root bifurcation. Such a tooth morphology occupies an intermediate position between the non-mammalian cynodonts and the early mammals, as is evident from the co-occurrence of various cynodont dental morphotypes in the Tiki Formation. Moreover, Late Triassic cynodonts occurred along narrow belts demarcated by paleolatitudes, though the Indian fauna shows both Laurasian and Gondwanan affinities. UUID: http://zoobank.org/c2c575ad-ee23-4f33-8a30-661c548a5b17


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Richard S. Kelly ◽  
Andrew J. Ross ◽  
Robert A. Coram

Species previously attributed to Necrotauliidae are revised from the Late Triassic and Early Jurassic of England based on examination of type specimens and non-type material. The necrotauliids have been considered as a basal family of caddisflies (Trichoptera) or as a paraphyletic assemblage of stem-amphiesmenopterans. Herein a new genus, Austaulius, is erected which includes all Lilstock Formation∖Lower Lias material from England; the previously described species are synonymized with A. furcatus and a new species, A. haustrum, is described from the Dorset Coast, the holotype of which preserves synapomorphic traits of the Trichoptera not previously described suggesting that the family is trichopteran. The type genus remains Necrotaulius and type species N. parvulus (Geinitz, 1884) from the type locality of Dobbertin, Germany. One species of Necrotaulius is represented in the UK, N. parvulus, which is found in the Upper Lias.


2021 ◽  
Vol 9 ◽  
Author(s):  
Chuanjiang Zhou ◽  
Wenwen Ma ◽  
Xi Wang ◽  
Yongtao Tang ◽  
Xiaoling Meng ◽  
...  

The genus Homatula belongs to the order Cypriniformes and family Nemacheilidae. Nichols (1925) set up the genus as a subgenus of Barbatula by the type species of Nemacheilus potanini. Currently, it is recognised as a valid genus. Nineteen valid species have been already reported in the drainage of the Yellow, Yangtze, Pearl, Lancang, Red and Nujiang Rivers. H. variegata, H. longidorsalis, H. berezowskii and H. potanini are distributed in the Yangtze River drainage in China. H. laxiclathra is mainly distributed in the Weihe River, a tributary of the Yellow River. The remaining species are mainly distributed in the rivers of Yunnan Province. Homatula guanheensis sp. nov., a new species, is described from the Guanhe River of the HanJiang River drainage (a tributary of the Yangtze River), Xixia County, Henan Province, China. It can be distinguished from its congeners by a combination of the following characters: the vertical brown bars on the body are wider than their interspaces, numbering 19–22; predorsal body partially scaled; the lateral line complete; adipose crest on caudal peduncle not reaching forward; the position of the anal-fin origin and the intestinal form. The new species displays distinct molecular divergence in the Cytochrome oxidase I (COI) and Cytochrome b (Cyt b) genes.


2020 ◽  
Vol 191 (1) ◽  
pp. 113-149 ◽  
Author(s):  
Martín D Ezcurra ◽  
Richard J Butler ◽  
Susannah C R Maidment ◽  
Ivan J Sansom ◽  
Luke E Meade ◽  
...  

Abstract Neotheropoda represents the main evolutionary radiation of predatory dinosaurs and its oldest records come from Upper Triassic rocks (c. 219 Mya). The Early Jurassic record of Neotheropoda is taxonomically richer and geographically more widespread than that of the Late Triassic. The Lower Jurassic (upper Hettangian–lower Sinemurian) rocks of central England have yielded three neotheropod specimens that have been assigned to two species within the genus Sarcosaurus, S. woodi (type species) and S. andrewsi. These species have received little attention in discussions of the early evolution of Neotheropoda and recently have been considered as nomina dubia. Here, we provide a detailed redescription of one of these specimens (WARMS G667–690) and reassess the taxonomy and phylogenetic relationships of the genus Sarcosaurus. We propose that the three neotheropod specimens from the Early Jurassic of central England represent a single valid species, S. woodi. The second species of the genus, ‘S. andrewsi’, is a subjective junior synonym of the former. A quantitative phylogenetic analysis of early theropods recovered S. woodi as one of the closest sister-taxa to Averostra and provides new information on the sequence of character state transformations in the lead up to the phylogenetic split between Ceratosauria and Tetanurae.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2592 ◽  
Author(s):  
Maxime Debuysschere

The earliest mammaliaforms are difficult to assess because the fossil record is poor and because their distinctive morphologies cannot be directly compared with more recent mammaliaforms. This is especially true for the haramiyid genusTheroteinus, only known in the Saint-Nicolas-de-Port locality (Rhaetian, France). This study presents a new definition of the type-speciesTheroteinus nikolai. A new speciesTheroteinus rosieriensis, sp. nov., is named and distinguished by the lingual shift of distal cusps, a larger size, and a stockier occlusal outline. Comparisons withEleutherodon,MegaconusandMillsodonsuggest thatTheroteinushas potential close relatives among the Jurassic haramiyids.


1987 ◽  
Vol 61 (4) ◽  
pp. 773-786 ◽  
Author(s):  
Phillip A. Murry

New records of Late Triassic reptiles from the Chinle Formation of Arizona include a new species of small trilophosaurid, a sphenodontid, and two taxa of eolacertilians. ?Trilophosaurus jacobsi n. sp. is a small trilophosaurid showing affinities to the type of Trilophosaurus buettneri of the southwestern United States and Variodens inopinatus from the Upper Triassic of Great Britain. A sphenodontid is also reported along with maxillae tentatively referred to the Kuehneosauridae and a jaw fragment from a subpleurodont eolacertilian with polycuspate teeth.


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