Ostracods (Crustacea) associated with microbialites across the Permian-Triassic boundary in Dajiang (Guizhou Province, South China) Author Forel, Marie-Béatrice text European Journal of Taxonomy 2012 2012-08-01 19 1 34 journal article 21834 10.5852/ejt.2012.19 9a19c75e-a62b-4143-adda-28789a95da5c 2118-9773 3857896 893DB151-7B86-485C-932F-A01C57B20316 Orthobairdia jeanlouisi sp. nov. Fig. 11 T-X Diagnosis Species of Orthobairdia with preplete carapace, sharp angles between PDB, DB and ADB (~150°) and large radius of curvature at AB and PB. Etymology Personal dedication to Jean-Louis Forel. Material examined Holotype One carapace ( Fig. 11T ), sample 05PAJ43, collection number P6M3077 . Paratype One carapace ( Fig. 11V ), sample 05PAJ43, collection number P6M3079. Other material 13 carapaces, several fragments. The species is known from its type locality only. Type locality Daye Formation (samples 05PAJ43-45), Dajiang section ( 25°33’56’’N- 106°39’41’’E ), Guizhou Province , South China , Griesbachian, Early Triassic. Fig. 12. Height/length diagram of Orthobairdia jeanlouisi sp. nov. Measurements ( Fig. 12 ) L = 422 – 918 μm; H = 250 – 546 μm; H/L = 0.50 – 0.75. Description Carapace subtriangular in lateral view; surface smooth; LV overlapping RV all around the carapace, dorsal overlap thicker; angles between PDB, DB and ADB ~ 150° at both valves; PDB straight with steep backward slope; DB and ADB long, together ~ 60% of Lmax; DB straight at both valves, bent backward; ADB straight at LV, slightly convex at RV, less steep than PDB; VB concave; AVB long and gently rounded; PVB shorter, gently rounded; AB subtriangular, with large radius of convexity, maximum located above mid-H; PB subtriangular, sharply pointed, with narrower but still large radius of curvature, maximum located slightly below mid-H; carapace preplete; Lmax located at mid-H or slightly below. Remarks Orthobairdia jeanlouisi sp. nov. can be compared to Orthobairdia texana (Harlton, 1927) sensu Shi & Chen, 2002 from the Late Permian of Heshan and Yishen, Guangxi Province , South China ( Shi & Chen 2002 ) but here the species is shorter, posterior maximum of convexity is clearly situated more dorsally, anterior part is more elongated, ADB steeper. Orthobairdia jeanlouisi sp. nov. is also close to Orthobairdia exilimarginata Chen, 1987 from the Changhsingian (Late Permian) of the Meishan section, Zhejiang Province , South China ( Shi & Chen 1987 ), but the new species is less elongated and its DB is shorter and bent backward. This species can also be related to Orthobairdia meishanensis Chen, 1987 from the Permian of the Meishan section, Zhejiang Province , South China ( Shi & Chen 1987 ), however, Orthobairdia jeanlouisi sp. nov. has the PB located higher, a shorter DB and a less steep PDB.