scholarly journals An enigmatic Arthropoda from the Upper Triassic (Carnian) southwestern Gondwana (Argentina)

2019 ◽  
Vol 94 (2) ◽  
pp. 279-290 ◽  
Author(s):  
María B. Lara ◽  
Bárbara Cariglino ◽  
Ana M. Zavattieri ◽  
Iracema Zacarías

AbstractThe presence of a new taxon, Duraznovis gallegoi new genus new species is reported and described from an early Late Triassic (Carnian) deposit in Argentina. Two specimens, recovered from the Quebrada del Durazno locality, uppermost levels of the Potrerillos Formation, Cuyana Basin (Mendoza), are represented by the molds of their shield and imprints of soft parts. The identity of these specimens appears enigmatic but closely resembles in the possession of a generalized arthropod morphology and a distinctive combination of characters, to living and fossil representatives of xiphosurans (Chelicerata) and notostracans (Branchiopoda). The new fossils are associated with a rich biota comprising abundant insects, spinicaudatans, plants, and scarce fish remains living in semipermanent swamps and/or ponds within a delta plain environment with intermittent episodes of flooding, in a warm temperate and humid megamonsoonal climate during Triassic times. In this context, we analyze the taphonomic and ecological implications of their presence. Lastly, these unique specimens at the Quebrada del Durazno locality adds to the diversity of the biota, revealing the importance of this site as an exceptional paleontological Triassic deposit.UUID: http://zoobank.org/8d1194c2-170c-4b7a-b0c6-5c08b0974d95

2018 ◽  
Vol 58 (2) ◽  
pp. 107-119 ◽  
Author(s):  
Eliana P. Coturel ◽  
Josefina Bodnar ◽  
Eduardo M. Morel ◽  
Daniel G. Ganuza ◽  
Ana J. Sagasti ◽  
...  

AbstractA new species of Osmundopsis Harris is described based on several impression-compression fossils from the upper section of the Potrerillos Formation (Uspallata Group) at Cerro Cacheuta Hill, Mendoza Province, Argentina. Osmundopsis zunigai sp. nov. is characterized by having fertile pinnae with a slender striate rachis, bearing widely separate, opposite to subopposite short falcate pinnules with an entire margin, rounded apex, and a partially reduced lamina. The pinnules bear sporangia loosely disposed in clusters of four or five on the abaxial side. The sporangia are wedge- to heart-shaped, shortly stalked, with cells of the apical region thickened, and have a vertical dehiscence slit. The spores are trilete and laevigate. This is the first record of Osmundopsis in the Triassic of Argentina. The mutual occurrence or co-preservation of Osmundopsis zunigai sp. nov. with sterile fronds of Cladophlebis kurtzi suggests the possibility that these species formed part of a dimorphic bipinnate frond. The diversity and geographic extent of fertile leaves of the Osmunda lineage in the early Late Triassic, with records in South Africa and Antarctica and now with this new taxon, support the idea of a moist mesothermal climatic belt in southern Gondwana.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7551 ◽  
Author(s):  
Jeffrey W. Martz ◽  
Bryan J. Small

The “red siltstone” member of the Upper Triassic Chinle Formation in the Eagle Basin of Colorado contains a diverse assemblage of dinosauromorphs falling outside of Dinosauria. This assemblage is the northernmost known occurrence of non-dinosaurian dinosauromorphs in North America, and probably falls within the Revueltian land vertebrate estimated biochronozone (215–207 Ma, middle to late Norian). Lagerpetids are represented by proximal femora and a humerus referable to Dromomeron romeri. Silesaurids (non-dinosaurian dinosauriforms) are the most commonly recovered dinosauromorph elements, consisting of dentaries, maxillae, isolated teeth, humeri, illia, femora, and possibly a scapula and tibiae. These elements represent a new silesaurid, Kwanasaurus williamparkeri, gen. et sp. nov., which possesses several autapomorphies: a short, very robust maxilla with a broad ascending process, a massive ventromedial process, a complex articular surface for the lacrimal and jugal, and 12 teeth; 14 dentary teeth; an ilium with an elongate and blade-like preacetabular process and concave acetabular margin; a femur with an extremely thin medial distal condyle and a depression on the distal end anterior to the crista tibiofibularis. The recognition of K. williamparkeri further demonstrates the predominantly Late Triassic diversity and widespread geographic distribution across Pangea of the sister clade to Asilisaurus, here named Sulcimentisauria. Silesaurid dentition suggests a variety of dietary specializations from faunivory and omnivory in the Middle Triassic and early Late Triassic (Carnian), to herbivory in the Late Triassic (Carnian and Norian), with the latter specialization possibly coinciding with the radiation of Sulcimentisauria across Pangea. The extremely robust maxilla and folidont teeth of K. williamparkei may represent a strong herbivorous dietary specialization among silesaurids.


2013 ◽  
Vol 44 (2) ◽  
pp. 167-174
Author(s):  
Yan Fang ◽  
Haichun Zhang ◽  
Bo Wang ◽  
Daran Zheng

A new genus and species of the cockroach family Caloblattinidae, Dazhublattella lini gen. et sp.n., is described from the Upper Triassic Xujiahe Formation of Sichuan Province, in southwestern China. The new taxon is similar to the Triassic Caloblattina mathildae (Geinitz, 1883) (Vršanský & Ansorge 2007) in the venation and pattern, but differs in the less elongated forewing with arched anterior margin. An elemental analysis of the wing is undertaken using Energy Dispersive X-ray analysis.


Author(s):  
Nikolay G. ZVERKOV ◽  
Dmitry V. GRIGORIEV ◽  
Andrzej S. WOLNIEWICZ ◽  
Alexey G. KONSTANTINOV ◽  
Evgeny S. SOBOLEV

ABSTRACT The first ichthyosaurian specimens discovered from the Upper Triassic of the Russian Arctic (Kotelny Island, New Siberian Islands) are described herein. They include the remains of large- to small-bodied ichthyosaurians originating from six stratigraphic levels spanning the lower Carnian to middle Norian. The material is mostly represented by isolated vertebrae and ribs, which are not possible to accurately diagnose, but also includes specimens comprising associated vertebrae and a fragmentary skeleton that preserves cranial remains (parabasisphenoid, fragmentary quadrate, partial mandible and hyoids). Based on vertebral and rib morphology, we identify the specimens as representatives of the following taxonomic groups: large-bodied shastasaurids, medium-sized indeterminate ichthyosaurians with a single rib facet in the presacral centra, and small euichthyosaurians with double rib facets present throughout the presacral vertebrae that likely represent toretocnemids and/or basal parvipelvians. In addition, the cranial and mandibular remains preserved in one of the specimens, ZIN PH 5/250, were studied using micro-computed tomography. Its mandible is highly similar to that of toretocnemids, whereas the parabasisphenoid demonstrates a peculiar combination of both plesiomorphic and derived character states, providing the first detailed data on this cranial element in a Late Triassic ichthyosaurian. Furthermore, the specimen also demonstrates a distinctive condition of rib articulation in the anteriormost presacral (cervical) vertebrae, which together with other features allows for the erection of a new taxon – Auroroborealia incognita gen. et sp. nov. Although the phylogenetic position of this taxon is uncertain due to its fragmentary nature, its anatomy, indicating toretocnemid or parvipelvian affinities, further supports the previously hypothesised sister-group relationships between these two clades. The morphology of the parabasisphenoid and vertebral column of the new taxon is discussed in broader contexts of the patterns of evolution of these skeletal regions in ichthyosaurs.


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.


2018 ◽  
Vol 5 (8) ◽  
pp. 180497 ◽  
Author(s):  
Ashley E. Latimer ◽  
Sam Giles

A new Triassic neopterygian is described on the basis of a large three-dimensional neurocranium from the Rhaetian (Late Triassic) of the Kössen Formation (Schesaplana, Grisons, Switzerland). CT scanning reveals neurocranial features similar to Dapedium , suggesting that this new genus, Scopulipiscis saxciput gen. et sp. nov., was deep-bodied and potentially durophagous, although no associated dental material is known. An expanded phylogenetic analysis of actinopterygians resolves Dapediidae as a clade (inclusive of Tetragonolepis ), although fails to recover any characters supporting the monophyly of the genus Dapedium . Dapediids are resolved as stem holosteans, filling a conspicuous gap in early neopterygian relationships. Pycnodonts, previously suggested as either stem teleosts or the sister group to dapediids, are resolved as a clade on the neopterygian stem. Similarities between the new taxon described here and Dapedium provide insights into morphological disparity within early members of the group—suggesting that the ecological expansion of dapediids originated prior to the End-Triassic extinction—as well as contributing to a growing understanding of endocranial anatomy in Palaeozoic and Early Mesozoic actinopterygians.


1995 ◽  
Vol 32 (3) ◽  
pp. 292-303 ◽  
Author(s):  
C. McGowan

A small, nearly complete ichthyosaur skeleton is described from the Upper Triassic of Williston Lake, in northeastern British Columbia. The age of the material, based on conodonts, is early Norian. Although the length of the entire skeleton would probably not have exceeded 1 m, there is no evidence of immaturity–quite the contrary. Named Hudsonelpidia brevirostris, the new taxon shares some features with Triassic taxa, as exemplified by Mixosaurus from the European Middle Triassic, and with post-Triassic ichthyosaurs like Ichthyosaurus, from the English Lower Jurassic. Mixosaurian characters include an elongate tibia with emarginated pre- and postaxial margins, and phalanges in the hindfin with pre- and postaxial notches. Like Ichthyosaurus, the humérus is elongate rather than broad, so too is the pubis and ischium. Mixosaurus is unusual among Triassic ichthyosaurs for having a relatively large orbit, but the orbit is even more prominent in Hudsonelpidia, probably because of the shortness of the snout. Hudsonelpidia has an unusually large femur that approaches the length of the humérus, dwarfing the rest of the hindfin. The rostrum is unique in being perforated by foramina, but this could possibly be an abnormality.


2008 ◽  
Vol 27 (2) ◽  
pp. 125-134 ◽  
Author(s):  
Ebrahim Ghasemi-Nejad ◽  
Martin J. Head ◽  
Maryam Zamani

Abstract. Upper Triassic (Norian) strata of the Miankuhi Formation in northeastern Iran have been studied palynologically, revealing a diverse but poorly preserved association of dinoflagellate cysts. Based on representatives of the genera Hebecysta, Heibergella, Rhaetogonyaulax and Sverdrupiella, the strata are assigned to the middle of the Hebecysta balmei Zone with an inferred age of early Late Norian. The association shows similarities with assemblages from Australia, New Zealand, Indonesia, Northwest Europe, arctic Canada and Alaska, indicating an interconnection of warm Tethyan waters during the Late Triassic. The occurrence of Sverdrupiella species in the clastic, near-shore marine deposits of Miankuhi, and their presence in similar sedimentary facies world-wide, indicate that this genus was well adapted to clastic shallow-marine environments.


2020 ◽  
pp. 1-7
Author(s):  
Hans-Dieter Sues ◽  
Rainer R. Schoch

Abstract A new taxon of sphenodontian reptile, Micromenodon pitti new genus new species is described from the Upper Triassic (Carnian) Vinita Formation of the Richmond basin of the Newark Supergroup in Virginia. It is diagnosed by a dorsoventrally deep facial process of the maxilla that extends for almost the entire anteroposterior length of the bone and by obtusely conical, strongly ribbed additional teeth in the maxilla that comprise a greatly enlarged tooth followed by smaller teeth posteriorly. Phylogenetic analysis found Micromenodon pitti n. gen. n. sp. as an early-diverging sphenodontian with fully acrodont tooth implantation. The maxillary dentition appears functionally suited for processing hard arthropod exoskeletons and snail shells. UUID: http://zoobank.org/40ed7cb6-4867-464b-8bfb-db07febfe97c


2020 ◽  
Vol 3 (3) ◽  
pp. 245-247 ◽  
Author(s):  
YANZHE FU ◽  
DIYING HUANG

Recently, Lara et al. (2020a, b) described a new fossil taxon, Duraznovis gallegoi, based on two specimens from the Upper Triassic Potrerillos Formation at Quebrada del Durazno, Cuyana Basin of Argentina. This fossil is considered to be an enigmatic arthropod closely resembling the living and fossil representatives of xiphosurans (Chelicerata) and notostracans (Branchiopoda), two completely different arthropod groups with convergent body plans. Some distinctive combination of features, however, makes the systematic position of these specimens indeterminate (Lara et al., 2020a, b).


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