Bairdianella cuspis Buschmina 1970
Bairdianella cuspis Buschmina, 1970 Fig. 11P Bairdianella cuspis Buschmina, 1970: 73, pl. V fig. 2. Bairdianella cuspis – Kotschetkova & Janbulatova 1987: pl. 24 fig. 1. — Zhuravlev & Sobolev 2019: figs 4i–j. – Sobolev 2020: figs 5–10. Material examined CHINA • 1 complete carapace (Fig. 11P)...
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Zenodo
2022
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Online Access: | https://dx.doi.org/10.5281/zenodo.6369147 https://zenodo.org/record/6369147 |
Summary: | Bairdianella cuspis Buschmina, 1970 Fig. 11P Bairdianella cuspis Buschmina, 1970: 73, pl. V fig. 2. Bairdianella cuspis – Kotschetkova & Janbulatova 1987: pl. 24 fig. 1. — Zhuravlev & Sobolev 2019: figs 4i–j. – Sobolev 2020: figs 5–10. Material examined CHINA • 1 complete carapace (Fig. 11P); Blue Snake section, Tangbagou Formation, sample 19BAI 03; P6M 3973 • 25 complete carapaces; Blue Snake section, Tangbagou Formation, samples 19BAI 01-03, 19BAI 05, 19BAI 37, 19BAI 39, 19BAI 44. All from the Tournaisian, early Carboniferous. Dimensions RV: L = 460–575µm, H = 188–247µm, H/L = 0.37–0.45. LV: L = 460–587 µm, H = 201–255 µm, H/L = 0.38–0.48. Remarks Our material is smaller than the holotype shown in Buschmina (1970: pl: 5 fig. 2) with L = 625µm, H = 325 µm, H/L = 0.52. Specimens shown in Kotschetkova & Janbulatova (1987: pl. 24 fig. 1) from Mugodzhary, Western Kazakhstan and Sobolev (2020: figs 5, 9–10)) from Pechora Uplift, Russia, have a similar size to our material with respectively L = 532µm, H = 250 µm and H/L = 0.47 and L = 580µm, H = 280 µm, H/L = 0.48. However, the specimen shown in Zhuravlev & Sobolev (2019) from North Ural is slightly larger than the present material with L = 580µm, H = 275µm and H/L = 0.47 but still smaller than the holotype in Buschmina (1970). The size variations in our material indicate that at least two stages are present and may correspond to juveniles, compare to the holotype in Buschmina (1970), but the wide distribution of the dimensions of the specimens does not allow to clearly discriminate them. Five species have been mentioned as Bairdianella aff. cuspis in papers discussing Devonian– Carboniferous ostracod faunas, they are summarized in Table 3. Based on specimens shown in these different contributions, the main differences between these species and Bairdianella cuspis Buschmina, 1970 seem to be weak variations of the length of the carapace, concavity at VB, degree of postero-dorsal angulation, posterior end more or less rounded and AVB sometimes truncated (visible only on Bairdianella sp. A, aff. cuspis Buschmina, 1970 in Casier et al. 2004). Specimens of Bairdianella aff. cuspis Buschmina, 1970 sensu Kotschetkova & Janbulatova 1987 in Casier et al. (2002), Bairdianella sp. A, aff. cuspis Buschmina, 1970 in Casier & Préat (2003) and Bairdianella sp. B, aff. cuspis Buschmina, 1970 in Casier et al. (2004) are also larger than the holotype but others had sizes similar to our material so may also correspond to juveniles. These differences do not seem sufficient to reasonably distinguish these forms from the species described by Buschmina (1970). However, only one specimen is shown in each of these papers with no discussion on possible other specimens, ontogenetic and intraspecific variations within the material or comparisons between these different species. Only a complete review of these taxa, based on close observations of all these specimens, can clarify this major issue. For this reason, they are kept as distinct species. Occurrence Gengis horizon, Yeltsov synclinorium, South of Occidental Siberia, early Carboniferous (Buschmina 1970). Berchogur section, Mugodzhary, Western Kazakhstan, Devonian–Carboniferous transition (Kotschetkova & Janbulatova 1987). Kamenka River section, North Urals, Russia, Famennian– Tournaisian, late Devonian–early Carboniferous (Zhuravlev & Sobolev 2019). Yjid-Kamenka river section, Pechora Uplift, Russia, Famennian–Tournaisian, late Devonian–early Carboniferous (Sobolev 2020). Samples 19BAI 01-03, 19BAI 05, 19BAI 37, 19BAI 39, 19BAI 44, Tangbagou Formation, Blue Snake section, Tournaisian, early Carboniferous (this work). : Published as part of Guillam, Elvis, Forel, Marie-Béatrice, Song, Junjun & Crasquin, Sylvie, 2022, Late Devonian-early Carboniferous ostracods (Crustacea) from South China: taxonomy, diversity and implications, pp. 1-62 in European Journal of Taxonomy 804 on pages 36-37, DOI: 10.5852/ejt.2022.804.1689, http://zenodo.org/record/6359315 : {"references": ["Buschmina L. S. 1970. Ostracodes from the boundary layers of the Devonian and Carboniferous of the Yeltsov synclinorium (south of Western Siberia). In: General questions of researches of microphauna of Siberia, Far East and other areas. Moscow: Nauka: 60 - 76. [In Russian.]", "Kotschetkova N. & Janbulatova M. 1987. Ostracodes. In: Maslov B. (ed.) Fauna and Biostratigraphy of Boundary Deposits of the Devonian and Carboniferous of Bertchogyra (Mugodzary): 76 - 91. Academy of Sciences of the USSR, Bashkirian Branch, Institute of Geology, Moscow. [In Russian.]", "Zhuravlev A. V. & Sobolev D. B. 2019. Devonian - Carboniferous boundary in the East of the Pechora Plate (Kamenka River and Vangyr River sections). Vestnik IG Komi SC UB RAS 10: 16 - 22. https: // doi. org / 10.19110 / 2221 - 1381 - 2019 - 10 - 16 - 22 Manuscript received: 24 September 2021", "Sobolev D. B. 2020. Ostracodes from the Devonian-Carboniferous boundary deposits on the reference section Yjid-Kamenka river (Pechora Uplift). Vestnik of Geosciences, 12 (312): 4 - 25. https: // doi. org / 10.19110 / geov. 2020.12.1", "Casier J. - G., Mamet, B., Preat, A. & Sandberg C. A. 2004. Sedimentology, conodonts and ostracods of the Devonian - Carboniferous strata of the Anseremme railway bridge section, Dinant Basin, Belgium. Bulletin de l'Institut royal des Sciences naturelles de Belgique, Sciences de la Terre 74: 45 - 68.", "Casier J. - G., Lethiers F. & Preat A. 2002. Ostracods and sedimentology of the Devonian - Carboniferous stratotype section (La Serre, Montagne Noire, France). Bulletin de l'Institut royal des Sciences naturelles de Belgique, Sciences de la Terre 72: 43 - 68.", "Casier J. - G. & Preat A. 2003. Ostracods and lithofacies of the Devonian - Carboniferous boundary beds in the Avesnois, North of France. Bulletin de l'Institut royal des Sciences naturelles de Belgique, Sciences de la Terre 73: 83 - 107."]} |
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