scholarly journals The osteology and phylogenetic position of the loricatan (Archosauria: Pseudosuchia) Heptasuchus clarki, from the ?Mid-Upper Triassic, southeastern Big Horn Mountains, Central Wyoming (USA)

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10101
Author(s):  
Sterling J. Nesbitt ◽  
John M. Zawiskie ◽  
Robert M. Dawley
Keyword(s):  
Middle Triassic ◽  
Type Locality ◽  
Late Triassic ◽  
Phylogenetic Position ◽  
Early Portion ◽  
Triassic Period ◽  
Big Horn Mountains ◽  
Western Portion ◽  
Early Late

Loricatan pseudosuchians (known as “rauisuchians”) typically consist of poorly understood fragmentary remains known worldwide from the Middle Triassic to the end of the Triassic Period. Renewed interest and the discovery of more complete specimens recently revolutionized our understanding of the relationships of archosaurs, the origin of Crocodylomorpha, and the paleobiology of these animals. However, there are still few loricatans known from the Middle to early portion of the Late Triassic and the forms that occur during this time are largely known from southern Pangea or Europe. Heptasuchus clarki was the first formally recognized North American “rauisuchian” and was collected from a poorly sampled and disparately fossiliferous sequence of Triassic strata in North America. Exposed along the trend of the Casper Arch flanking the southeastern Big Horn Mountains, the type locality of Heptasuchus clarki occurs within a sequence of red beds above the Alcova Limestone and Crow Mountain formations within the Chugwater Group. The age of the type locality is poorly constrained to the Middle—early Late Triassic and is likely similar to or just older than that of the Popo Agie Formation assemblage from the western portion of Wyoming. The holotype consists of associated cranial elements found in situ, and the referred specimens consist of crania and postcrania. Thus, about 30% of the osteology of the taxon is preserved. All of the pseudosuchian elements collected at the locality appear to belong to Heptasuchus clarki and the taxon is not a chimera as previously hypothesized. Heptasuchus clarki is distinct from all other archosaurs by the presence of large, posteriorly directed flanges on the parabasisphenoid and a distinct, orbit-overhanging postfrontal. Our phylogenetic hypothesis posits a sister-taxon relationship between Heptasuchus clarki and the Ladinian-aged Batrachotomus kupferzellensis from current-day Germany within Loricata. These two taxa share a number of apomorphies from across the skull and their phylogenetic position further supports ‘rauisuchian’ paraphyly. A minimum of three individuals of Heptasuchus are present at the type locality suggesting that a group of individuals died together, similar to other aggregations of loricatans (e.g., Heptasuchus, Batrachotomus, Decuriasuchus, Postosuchus).

Chapter 18 Triassic history

1997 ◽  
Vol 17 (1) ◽  
pp. 340-362 ◽  
Author(s):  
W. Brian Harland ◽  
Isobel Geddes
Keyword(s):  
Middle Triassic ◽  
Early Jurassic ◽  
Late Triassic ◽  
Early Triassic ◽  
Marked Contrast ◽  
Angular Unconformity ◽  
Triassic Period ◽  
Age Determinations

The Triassic Period of about 40 million years dutation spanned about a third of that of the Carboniferous and Permian interval. The Triassic rocks of Svalbard are easily distinguished from the underlying Permian strata because of a distinct desconformity between them and a marked contrast in facies from the resistant. pale coloured, cherls and siliciclastics of the Kapp Starostin Formation to the softer, darker areno-argillaceous Vardebukta and equivalent formations. Figure 18.1 shows the distribution of Triassic strata in Svalbard.The minor angular unconformity represents a hiatus mainly in the Permian rather than the Triassic record. The dominantly argillaceous facies constitute the Early Triassic to Late Middle Triassic Sassendalen Group. The rocks can be well dated from ammonoids, typically within calcareous concretions in the shales.The succeding Kapp Toscana Group is distinguished by a dominatly sandy deltaic facies in which age determinations are difficult. It spans both Late Triassic and Early Jurassic spoehs (roughly mid-Ladinian to mid-Bathonian). The Triassic-Jurassic boundary is not easy to estimate. Nevertheless towards the end of Triassic time (e.g. Rhaetian) the overall scene changed. Thus of the three formations of the Kapp Toscana Group the lower two (Tschermakfjellet and De Geerdalen) belong to the Triassic story. The overlying Wilhelmøya Formation may possibly range from Latest Triassic through Liassic time, and due to its complexity it is also discussed in the Jurassic-Crataceous chapter (19).The facies of the two groups reflect two distinct environmental configurations. The Sassendalen Group was deposited on a distal marine muddy shelf with a

Stratigraphic and tectonic implications of Triassic conodonts from northwest Peninsular Malaysia

1990 ◽  
Vol 127 (6) ◽  
pp. 567-578 ◽  
Author(s):  
I. Metcalfe
Keyword(s):  
Middle Triassic ◽  
Carbonate Platform ◽  
Peninsular Malaysia ◽  
Late Triassic ◽  
Time Interval ◽  
Rift Basin ◽  
Marine Carbonate ◽  
Arc Setting ◽  
North Sumatra ◽  
Early Late

AbstractThe Chuping Limestone of northwest Peninsular Malaysia, until recently considered entirely of Permian age, has yielded late Triassic (early Norian) conodonts. TheLimestone thus spans the time interval late Early Permian–Late Triassic and is in part equivalent to the Kodiang Limestone (Late Permian–Late Triassic) in Kedah andsimilar limestone sequences in south Thailand and north Sumatra. Early Late Triassic (Carnian) conodonts are also reported from pelagic limestones associated with bedded chertsof the Chert Member of the Semanggol Formation in Kedah. The Chert Member, previously considered of Middle Triassic age, is re-interpreted to represent Early, Middle and early Late Triassic deposition. The Triassic sedimentary rocks of the Malay Peninsula represent three distinct sedimentary regions: a stable shallow marine carbonate complex (ChupingLimestone, Kodiang Limestone), which forms part of an elongate carbonate platform on theSibumasu block; a deep water pelagic/turbidite basinal sequence (Semanggol Formation) which accumulated in either a foredeep basin or an intracratonic pull-apart basin related to strike-slip faulting; and a volcanic-sourced volcaniclastic basinal sequence on the East Malaya block (Semantan Formation and equivalents) which accumulated in either a forearc/intra-arc setting, or in a post-orogenic rift basin.

scholarly journals A new diapsid from the Middle Triassic of southern China

2017 ◽  
Vol 91 (6) ◽  
pp. 1306-1312 ◽  
Author(s):  
Chun Li ◽  
Nicholas C. Fraser ◽  
Olivier Rieppel ◽  
Li-Jun Zhao ◽  
Li-Ting Wang
Keyword(s):  
Yunnan Province ◽  
Middle Triassic ◽  
Southern China ◽  
Late Triassic ◽  
New Taxon ◽  
Remarkable Similarity ◽  
The Absolute ◽  
Absolute Age ◽  
Marly Limestone ◽  
Early Late

AbstractThe Middle and early Late Triassic of southern China is well known for a remarkable diversity of marine vertebrates, particularly reptiles, including an abundance of intriguing new forms (e.g., Jiang et al., 2005; Hu et al., 2011; Li et al., 2016). Here we describe a new diapsid from Yunnan Province. It possesses an elongate neck that exhibits a remarkable similarity to that of many Protorosauria, yet in other respects the skull and postcranium are much less derived.The new taxon is part of the so-called Panxian-Luoping Fauna and the deposits correspond to the Upper Member of the Guanling Formation, comprising thin to medium bedded, gray to dark-gray laminated marly limestone and limestone, with several layers of bentonite intercalated in the fossil level at Panxian (Wan, 2002; Motani et al., 2008; Jiang et al., 2009). Their age is Pelsonian (middle Anisian, Middle Triassic) as is indicated by the conodont Nicoraella kockeli Zone (Sun et al., 2006; Zhang et al., 2009). A recent U-Pb study indicates the absolute age of these middle Anisian beds to be close to 244 Ma (Wang et al., 2014).

Diversity and distribution of Triassic bryozoans in the aftermath of the end-Permian mass extinction

2008 ◽  
Vol 82 (2) ◽  
pp. 362-371 ◽  
Author(s):  
Catherine M. Powers ◽  
Joseph F. Pachut
Keyword(s):  
Surface Area ◽  
Mass Extinction ◽  
Carbonate Rock ◽  
Middle Triassic ◽  
Late Triassic ◽  
Early Triassic ◽  
Diversity Pattern ◽  
Extinction Rates ◽  
Permian Mass Extinction ◽  
Early Late

Seventy-three species of stenolaemate bryozoans are documented worldwide from the Triassic. Stage-level diversity and paleogeographical analyses reveal that the recovery of bryozoans following the end-Permian mass extinction was delayed until the Middle Triassic. Early Triassic bryozoans faunas, dominated by members of the Order Trepostomida, were depauperate and geographically restricted. Bryozoan diversity increased during the Middle Triassic and diversity peaked in the Carnian (early Late Triassic). High extinction rates throughout the Late Triassic led to the extinction of all stenolaemate orders except the Cyclostomida by the end of the Triassic. Comparisons between global carbonate rock volume, outcrop surface area, and bryozoan diversity indicate that the documented diversity pattern for bryozoans may have been related, in part, to the availability of carbonate environments during the Triassic.

Electrophilic activation of alkynes for enyne cycloisomerization reactions with in situ generated early/late heterobimetallic Pt–Ti catalysts

2016 ◽  
Vol 45 (24) ◽  
pp. 9770-9773 ◽  
Author(s):  
Michael R. Talley ◽  
Ryjul W. Stokes ◽  
Whitney K. Walker ◽  
David J. Michaelis
Keyword(s):  
Room Temperature ◽  
Electrophilic Activation ◽  
Early Late

In situ assembly of a heterobimetallic Pt–Ti catalyst from a titanium-containing phosphinoamide ligand enables fast room temperature catalysis in enyne cycloisomerization reactions.

A newPaleorhinusfauna in the Early Late Triassic of Poland

2001 ◽  
Vol 21 (3) ◽  
pp. 625-627 ◽  
Author(s):  
Jerzy Dzik
Keyword(s):  
Late Triassic ◽  
Early Late

scholarly journals Martensopsalis, a new genus of Neopilionidae from New Caledonia (Opiliones: Eupnoi)

Zootaxa ◽  
2021 ◽  
Vol 4984 (1) ◽  
pp. 98-107
Author(s):  
GONZALO GIRIBET ◽  
CAITLIN M. BAKER ◽  
DAMIEN BROUSTE
Keyword(s):  
Type Species ◽  
New Genus ◽  
New Caledonia ◽  
Ventral Side ◽  
External Morphology ◽  
Type Locality ◽  
Phylogenetic Position ◽  
Formal Description ◽  
Undescribed Species

New Caledonia has an endemic opiliofauna with two named species of Triaenonychidae, 17 Troglosironidae and eight Zalmoxidae. The recent finding of Neopilionidae on Grande Terre was thus surprising, and required the formal description of a new genus, which we undertake here. Martensopsalis gen. nov. is characterized by a small unsclerotized body with a unique palp with a pointed basal apophysis on the ventral side of the femur and with a distal apophysis on the prolateral side of the patella. The distinct external morphology, simple penis and unique phylogenetic position justify the erection of the new genus with Martensopsalis dogny spec. nov. as its type species. In addition to the type locality we report several other localities of putative congeneric, yet undescribed species. 

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