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Ostracods from the Late Permian and Permian–Triassic boundary of Tibet. Scale bar is 100 m. All the specimens come from the Gyanyima section in southwestern Tibet. For distribution see Table 1. (A) Acratia cf. subfusiformis Wang, 1978; right lateral view of a right valve; NIGP141947, Early Triassic. (B) Bairdia sp. A; right lateral view of a broken carapace; NIGP141948, Late Permian. (C) Bairdia cf. crassa Harlton, 1929; right lateral view of an almost complete carapace; NIGP141949, Late Permian. (D) Bairdia cf. antamputata Shaver, 1959; right lateral view of a complete carapace; NIGP141950; Late Permian. (E) Bairdia cf. meishanensis (Chen, 1987); right lateral view of an almost complete carapace; NIGP141951; Early Triassic. (F) Bairdia cf. Bairdia sp. B sensu Crasquin-Soleau et Baud, 1998; right lateral view of a broken carapace; NIGP141952; Late Permian. (G) Bairdia wangi n. nom. Crasquin-Soleau; right lateral view of a complete carapace; NIGP141953; Late Permian. (H) Bairdia cf. folgeri Kellett, 1934; right lateral view of an almost complete carapace; NIGP141954; Late Permian. (I) Bairdia cf. galei Croneis et Thurman, 1939; right lateral view of a broken carapace; NIGP141955; Late Permian. (J) Bairdia cf. heshanensis Chen, 2002; right lateral view of a complete carapace;
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Ostracods are reported for the first time in the Late Permian Lopingian to earliest Triassic carbonate sequence in the Ngari region, southwestern Tibet, China. Fifty-three species are recognized, of which 19 are illustrated. One new species (Carinaknightina tibetensis n. sp.) is described and one species is renamed (Bairdia wangi n. nom.). The ostr...
Contexts in source publication
Context 1
... cf. antamputata Shaver, 1959 Fig. 3D Remarks: The present specimen is similar to Bair- dia antamputata Shaver, 1959 (Pennsylvanian of North American platform; Shaver, 1959) from the Lopingian of Guangxi Autonomous Region ( Shi and Chen, 2002). However, the dorsal border is less angular. Occurrence: Samples Y-7-10 of the Xilanta Formation and Y-8-20 of the Gyanyima ...
Context 2
... cf. dubius ) Fig. 3N Remarks: Our specimen is very close to Bairdiacypris dubius ) from the Lopingian of Guangxi (Shi and Chen, 2002). The only doubt is due to the poor preservation of the posterior part of the carapace. Occurrence: Sample Y-4-14; from Unit 4 of the Gyany- ima Formation; Late ...
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Through geological times, the main turnover of marine ostracod group occurred at the Permian – Triassic boundary (PTB) when the Palaeozoic world gave way to Meso-Cainozoic world. As quite all the groups, ostracods intensively suffered of the end Palaeozoic events but they have the particularity to pass the PTB and to be present in quite all marine...
Citations
... Dozens of publications have reported P-Tr ostracod faunas in various facies, including neritic clastic (Hao 1994), shallow carbonate (e.g. Crasquin et al. , 2006Crasquin et al. , 2007bCrasquin et al. , 2018Forel et al. 2009Forel et al. , 2013aForel et al. ,b, 2015a, and slope and deeper facies (Yuan et al. 2007;Crasquin et al. 2010). ...
... Brayard et al. (2010) argued that the rapid size increase of gastropods in the Smithian (about 1 Myr after LPME) indicated rapid ecosystem recovery. However, the transient ostracod size increase we observe in the Hindeodus parvus Zone did not result from rapid ecosystem recovery, but the domination by Hollinella suggests they were opportunistic assemblages rather than recovered Mesozoic assemblages (Crasquin et al. 2007b). Such dynamics have also been applied to explain the synchronous brachiopod size increase in deeper settings by Wu et al. (2018). ...
... Although further work is required, the recovery at genus level appears to be complete by the Anisian stage (Forel et al. work in progress), with the last unquestionable Palaeozoic representatives known before the discovery of the Kilek fauna. Based on these faunal characteristics, the transition interval during which Palaeozoic and Meso-Cenozoic taxa co-occurred was considered to extend from the Wuchiapingian stage of the Upper Permian to the Anisian stage of the Middle Triassic (Crasquin-Soleau et al. 2007a;Crasquin & Forel 2014). Following this description of the Kilek ostracod fauna, it is now possible to state that radiations of Palaeozoic taxa occurred up to the Carnian stage of the Late Triassic, for kirkbyoid Palaeocopida, Rectonariidae, Beecherellidae and Palaeozoic Bythocytheridae. ...
The Mersin Mélange, located in southern Turkey north-west of the city of Mersin, includes blocks and tectonic slices of different origins. The Kilek section in the Mersin Mélange was sampled for a thorough examination of its lithology, biostratigraphy and fossil content. Two samples from the cherty limestone layers within the Huglu Tuffites at the top of the section yielded a rich silicified ostracod fauna of late Early Carnian (based on a two-fold Carnian subdivision) or middle Middle Carnian age (based on a three-fold Carnian subdivision), deposited in an open marine environment, in the outer platform-upper slope zone. We report 121 ostracod species belonging to 53 genera. Two new genera are described: Edithobairdia Forel gen. nov. and Gencella Forel gen. nov., as well as 16 new species: Acanthoscapha mersinella Forel sp. nov., Bairdia hugluensis Forel sp. nov., Acratia kollmanni Forel sp. nov., Citrella? carniana Forel sp. nov., Cytheropteron? schornikovi Forel sp. nov., Eucytherura lacerata Forel sp. nov., Gencella taurensis Forel sp. nov., Kerocythere dorsidenticulata Forel sp. nov., Kerocythere tricostata Forel sp. nov., Monoceratina praevulsaformis Forel sp. nov., Patellacythere tourkosella Forel sp. nov., Polycope kilekensis Forel sp. nov., Ptychobairdia praekristanae Forel sp. nov., Simeonella daginikella Forel sp. nov., Spinomicrocheilinella reliquiaella Forel sp. nov. and Triassocythere tavuscayiriensis Forel sp. nov. The diagnosis of Acratia goemoeryi Kozur is emended. The Kilek fauna retains primitive characteristics illustrated by the first known occurrence of Palaeocopida and Rectonariidae (typical Palaeozoic forms) in the Late Triassic, associated with typical Triassic–modern elements such as thick-shelled and ornamented Bairdiidae and diverse Cytheroidea known from the Middle and Late Triassic worldwide. The unique composition of Palaeozoic and Mesozoic taxa from the Kilek section illustrates unexpected long-term survival in a deep-sea refuge zone following the end-Permian extinction, and the diachronous character of the ostracod recovery in different environments.
http://zoobank.org/urn:lsid:zoobank.org.pub:662C3D5C–2B86–4D7B–BDB5–8F8B6A1AD1E7
... nov. is similar to Bairdiacypris cf. B. dubius Shi, 2002(in Shi & Chen 2002 sensu Crasquin-Soleau et al. (2007) from Lopingian of southwestern Tibet, in the subrectangular lateral outline and AB higher than PB, but differs from it in its longer DB and ADB. ...
Silicified ostracods were recovered from Cisuralian micritic limestones of the Ryozensan Limestone Formation from the southwestern part of Ryozensan Mountain, Taga City located in Shiga Prefecture, Central Japan. Twenty-seven species belonging to 19 genera were obtained, of which six species are new and are described here: Bairdia tagaensis Tanaka sp. nov., Bairdiacypris ikeyanoriyukii Tanaka sp. nov., Kellettina noriyukii Tanaka sp. nov., Microcheilinella shigensis Tanaka sp. nov., Oliganisus ryozensannensis Tanaka sp. nov., and Pustulobairdia ohmiensis Tanaka sp. nov. Some Palaeozoic limestone localities in Japan cap greenstones and are surrounded by younger cherts (such as Mino Terrane of this study). They represent a characteristic reef and reef-slope environment around a seamount surrounded by deep sea ocean floor. This result is concordant with the ostracod assemblage. After this report, a Panthalassan ostracod fauna could be defined for the Cisuralian.
... and 80°41′42.4″E) was studied by a number of authors (Wang and Xu, 1988;Guo et al., 1991;Shen et al., 2001Shen et al., , 2003Shen et al., , 2010Crasquin-Soleau et al., 2007;Wang et al., 2010). It is located in Burang County, Ngari Region in southwestern Tibet, China, and is about 50 km northwest of the Town of Burang (Fig. 1). ...
The end of the Permian was a time of great death and massive upheaval in the biosphere, atmosphere and hydrosphere. Over the last decades, many causes have been suggested to be responsible for that catastrophe such as global warming, anoxia and acidification. The Gyanyima limestone block was an open ocean seamount in the southern Neotethys at subtropical latitude, and it affords us insight into open-ocean oceanographic changes during the end of the Permian After careful screening using multiple tests, we reconstructed carbonate/seawater curves from the geochemical data stored in pristine brachiopod shell archives from the shallow water limestone of the Changhsingian Gyanyima Formation of Tibet. The reconstructed strontium isotope curve and data for the late Changhsingian is relatively invariant about 0.707013, but in the upper part of the succession the values become more radiogenic climaxing at about 0.707244. The 87Sr/86Sr curve and trend is similar to that observed for the Upper Permian succession in northern Italy, but dissimilar (less radiogenic) to whole rock results from Austria, Iran, China and Spitsbergen. The Ce/Ce* anomaly results. ranging from 0.310 to 0.577 for the brachiopods and from 0.237 to 0.655 for the coeval whole rock before the event, and of 0.276 for whole rock during the extinction event, suggest normal redox conditions. These Ce* values are typical of normal open-ocean oxic water quality conditions observed in modern and other ancient counterparts. The biota and Ce* information clearly discounts global anoxia as a primary cause for the end-Permian biotic crisis. Carbon isotopes from brachiopod shells and whole rock are relatively invariant for most of the latest Permian interval, which is in stark contrast to the distinct negative carbon isotope excursion observed near and about the event. Estimates of seawater temperature at shallow depth fluctuated from 22.2 to 29.0 °C up to unit 8-2, and then gradually rise from 29.7 °C in unit 8-13 to values exceeding 35 °C at a stratigraphic level about 120 ky before the Permian-Triassic boundary, and just before the onset of the extinction interval. This dramatic increase in seawater temperature has been observed in global successions from tropical to mid latitude and from restricted to open ocean localities (e.g., northern Italy, Iran). The brachiopod archive and its geochemical proxies from Tibet support the paradigm that global warming must have been an important factor of the biotic crisis for the terrestrial and marine faunas and floras of the late Paleozoic world.
... Jones, 1970; Sohn, 1970; Wei, 1981; Hao, 1992; Crasquin-Soleau and Kershaw, 2005) ostracods . Our team analyzed intervals framing the boundary, the PTB reference sections (Fig. 3) at the GSSP in eastern China (Crasquin et al., 2010a; Forel and Crasquin, 2011a), in South China (Forel et al., 2009; Forel, 2010, 2012), Tibet (Crasquin et al., 2007; Forel et al., 2011), Northern Italy (Crasquin et al., 2008), Hungary (Forel et al., 2013), Turkey (Crasquin-Soleau et al., 2004a,b; Forel, 2010), Arabia (Crasquin-Soleau et al., 2005) (Table 1) and Northern Iran (Crasquin work in progress). Significant data on PTB ostracods from NE Iran were published by Mette (2010). ...
... Griesbachian. Griesbachian ostracods are now quite well documented in neritic environment in South China (Meishan GSSP, Crasquin et al., 2010a; Forel and Crasquin, 2011a; Dajiang in Guizhou, Forel, 2010, 2012), Tibet (Crasquin et al., 2007), Turkey (Crasquin-Soleau et al., 2004a,b; Forel, 2010; Forel et al. in progress), North Iran (Mette, 2010; Crasquin work in progress), Hungary (Forel et al., 2013), Northern Italy (Crasquin-Soleau et al., 2008) and punctually reported in Australia (Jones, 1970), Pakistan (Sohn, 1970), Kashmir (Agarwal, 1980; Agarwal et al., 1980), Sichuan (Wei, 1981; Crasquin-Soleau and Kershaw, 2005), Yunnan (Wang, 1978), Guizhou (Wang, 1978; Hao, 1992, 1994). Ostracods are absent from deep external platform environment: in West Pingdingshan section, Chaohu (we processed 150 samples spanning the 66 m of this section; all are barren of ostracods) and in the lower half of the Yinkeng formation in Meishan (except 3 species in the bed 29, just above PTB; Fig. 4). ...
... We sampled this section for ostracod analysis in the framework of a large−scale study on the extinction and recov− ery of this group through the PTB interval. This research was conducted in South China: Meishan GSSP, Zhejiang Province (Crasquin et al. 2010a; Forel and Crasquin 2011b); Guizhou Province (Forel et al. 2009); Sichuan Province (Crasquin− Soleau and Kershaw 2005); Guangxi Province (Crasquin− Soleau et al. 2006); in Tibet (Crasquin et al. 2007; Forel and ? ...
One of the most complete Permian-Triassic boundary sections located in the Bukk Mountains (Hungary) was sampled for ostracod study. Seventy−six species are recognized, belonging to twenty genera. Fifteen new species are described and figured: Acratia? jeanvannieri Forel sp. nov., Acratia nagyvisnyoensis Forel sp. nov., Bairdia anisongae Forel sp. nov., Bairdia davehornei Forel sp. nov., Callicythere? balvanyseptentrioensis Forel sp. nov., Cytherellina? magyarorsza− gensis Forel sp. nov., Eumiraculum desmaresae Forel sp. nov., Hollinella fengqinglaii Crasquin sp. nov., Hungarella gerennavarensis Crasquin sp. nov., Langdaia bullabalvanyensis Crasquin sp. nov., Liuzhinia venninae Forel sp. nov., Liuzhinia bankutensis Forel sp. nov., Microcheilinella egerensis Forel sp. nov., Reviya praecurukensis Forel sp. nov., Shemonaella? olempskaella Forel sp. nov. One species is renamed: Bairdia baudini Crasquin nom. nov. Comparison of the Balvany North section with the Meishan section (Zhejiang Province, South China), Global Boundary Stratotype Sec− tion and Point (GSSP) of the Permian-Triassic Boundary (PTB), reveals discrepancies linked to the environmental set− ting and particularly to bathymetry. The stratigraphical distribution of all the species is given and diversity variations are discussed. The Balvany North section exhibits the lowest extinction rate of all PTB sections studied for ostracods analysis associated with a high level of endemism.
... DISCUSSION Crasquin et al. (2007) described an early late Griesbachian age fauna from southwestern Tibet (Gyanyima section, Burang area) from which 14 species were recognized. Th e ostracod fauna presented in this paper is the fi rst described from late Early-Middle Triassic age sediments of Tibet. ...
Après l'extinction en masse de la limite Permien-Trias: nouveau genre et nouvelles espèces d'ostracodes du sud Tibet. Quarante-six échantillons ont été analysés pour l'étude des ostracodes du Trias inférieur et moyen (Smithien à Anisien) du sud Tibet. Quarante-quatre espèces appartenant à 15 genres ont été identifiées. Un genre et sept espèces sont nouveaux: Bairdia jeancharlesi Forel n. sp., Bairdia letangae Forel n. sp., Bairdiacypris combeae Forel n. sp., Petasobairdia collini Forel n. sp., Hungarella tulongensis Crasquin n. sp., Triassicindivisia tibetinella n. gen. n. sp., Liuzhinia larmae Forel n. sp. Le sujet de cet article est la description des nouveaux taxons en prélude à une reconstruction paléoenvironnementale.
... A lower Griesbachian fauna from Southwestern Tibet (Gyanyima section, Burang area) has previously been described in Crasquin-Soleau et al. (2007a), yielding 14 species. The ostracod faunas described here are the first ones recorded for Early and Middle Triassic times in Tibet. ...
Lower to Middle Triassic ostracods from the Tulong section, south Tibet, are described here for the first time. Samples from the first two stages of the Early Triassic (Griesbachian and Dienerian) are barren of ostracods; the following stage (Smithian) revealed low diversity ostracod faunas; a substantial diversification in taxa began at the base of the fourth stage (Spathian) and developed into the first stage of the Middle Triassic (Anisian). Furthermore, exploration of additional feeding modes is developed in the Spathian and Anisian, with notable occurrence of filter-feeding taxa. High abundance of filter-feeding ostracods in Spathian and lower Anisian units indicates that benthic habitats became oligotrophic. These habitats typically harbored ostracod faunas of Mesozoic affinities, suggesting that the evolutionary turnover of ostracods was fostered by the declining input of nutrients from the Spathian on. Marked faunal similarities with other Tethyan areas, mainly the northern part of Tethys, are observed during Spathian and Anisian times.Research Highlights► In this study we examine ostracod (Crustacea) faunas from Early and early Middle Triassic of Tulong section, Tibet. ► We examine palaeoenvironmental significance of these assemblages. ► We consider biodiversity indices in relation to feeding modes of ostracods. ► We give new insights into recovery mode in the aftermath of the end-Permian extinction.
... Ostracods are also one of the most diverse fossil groups in the Gyanyima Section. 53 species were recognized by Crasquin-Soleau et al. (2007). Except for one unidentifiable species of Paraparchitacea, and two species of Cavellinidae, all the ostracods recovered from the Late Permian (Lopingian) samples belong to Bairdiidae. ...
... All the representatives are smooth and appear to be thin-shelled except for the Ceratobairdia species. According to those ostracod association in the Gyanyima Formation, the environment was interpreted as being open marine, relatively deep on the external part of a platform, without variation of both salinity and bathymetry (Crasquin-Soleau et al., 2007). On contrary to the benthic coral, brachiopod and foraminifer faunas above, ostracods nearly has no change in composition into Early Triassic (Crasquin-Soleau et al., 2007). ...
... According to those ostracod association in the Gyanyima Formation, the environment was interpreted as being open marine, relatively deep on the external part of a platform, without variation of both salinity and bathymetry (Crasquin-Soleau et al., 2007). On contrary to the benthic coral, brachiopod and foraminifer faunas above, ostracods nearly has no change in composition into Early Triassic (Crasquin-Soleau et al., 2007). Nevertheless, the richness of ostracods is very different between the Permian and Triassic. ...
This paper documents a new Permian–Triassic carbonate sequence which recorded the end-Permian mass extinction in the isolated oceanic setting of Neotethys in southwestern Tibet, China. The sequence is over 350 m thick and consists of the Gyanyima and the Lower Lanchengquxia formations in ascending order. The Lopingian (Late Permian) Gyanyima Formation is composed of fossiliferous reddish carbonates dominated by Colaniella grainstone and reef facies including fenestrate/sponge/coral framestone and bafflestone. 156 species are recognized from the Lopingian Gyanyima Formation. Composite ranges of brachiopods, ostracods, rugose corals and foraminifers at the Gyanyima Section suggest that evolution and diversification of Permian marine organisms continued to the end-Permian preceding a major faunal extinction close to the Permian–Triassic boundary (PTB), coincident with a 2–3‰ negative shift of δ13Ccarb. The timing and accelerating extinction pattern and the negative δ13Ccarb excursion are largely comparable with those reported from many previously-documented sections on continental shelf environments.
... Just like the foraminifers, corals and ostracods from the Gyanyima Formation display close similarities to those observed in the Palaeotethys and are characteristic of warmwater platform deposits (Wang, 2006;Crasquin-Soleau et al., 2007). Corals are abundant in the lower and upper part of the formation, mainly species of Waagenophyllum, Ipciphyllum and Jiangyemaphyllum. ...
... The Gyanyima Limestone, with a relatively highly diversified foraminiferal fauna, may have been situated at relatively low latitudes in the Neotethys, where warm water from the subtropical Palaeotethys had major effects on the faunas. This is consistent with the corals and ostracodes from the Gyanyima Formation, which are also characteristic of warm-water platform deposits (Wang, 2006;Crasquin-Soleau et al., 2007). The brachiopods, on the other hand, indicate an alternation of warm, cool and warm conditions for the lower, middle and upper part of the Gyanyima Formation separately (Shen et al., 2009 in press). ...
The Gyanyima Limestone is one of the isolated carbonate build-ups that have a probable Neotethyan seamount origin, distributed along the Yarlung-Zangbo Suture in southern Tibet. The limestone yields a highly diversified foraminiferal fauna consisting of nine fusuline and 37 taxa of non-fusuline foraminifers. This foraminiferal fauna is dominated by Reichelina pulchra, Colaniella parva and the characteristic boultoniid genus Dilatofusulina. We propose a new foraminiferal zone, the Reichelina pulchra-Colaniella parva-Dilatofusulina orthogonios Zone that represents the last prosperous stage of foraminifers just before the end-Permian mass extinction. This zone can be correlated broadly with the Palaeofusulina sinensis Zone in the Eastern Tethys based on advanced features observed in the major elements of the fauna. The composition of the fauna suggests that during the late Changhsingian, the Gyanyima Limestone occupied a palaeogeographic position at lower latitudes in the Neotethys. The fauna was largely influenced by the warm-water equatoro-tropical Palaeotethys. Copyright © 2010 John Wiley & Sons, Ltd.
