Bairdia jeromei, Forel, 2012

Forel, Marie-Béatrice, 2012, Ostracods (Crustacea) associated with microbialites across the Permian-Triassic boundary in Dajiang (Guizhou Province, South China), European Journal of Taxonomy 19, pp. 1-34 : 11-13

Bairdia jeromei sp. nov.

Fig. 4 G-P

Diagnosis

Massive and subrectangular species of Bairdia , with DB and VB subparallel, long DB (~ 60% of Lmax), rhombic dorsal view.

Etymology

Personal dedication to Jérôme Cougoul.

Material examined

Holotype

One carapace ( Fig. 4G ), sample 05PAJ43, collection number P6M2945.

Paratype

One carapace ( Fig. 4J ), sample 05PAJ43, collection number P6M2948.

Other material

10 carapaces, several fragments. The species is known from its type locality only.

Type locality

Wujiaping and Daye Formations (samples 05PAJ23, 25, 26, 28, 32, 42, 43), Dajiang section (25°33’56’’N- 106°39’41’’E), Guizhou Province, South China, Changhsingian and Griesbachian, Late Permian and Early Triassic.

Measurements ( Fig. 6 )

L = 722 – 1024 μm; H = 410 – 597 μm; H/L = 0.56 – 0.64.

Description

Carapace massive, elongated and subrectangular in lateral view; surface smooth; LV larger than RV, overlapping at dorsum and VB; bairdian beaks at AB and PB poorly expressed; PDB, DB and ADB distinct at both valves; PDB steeply bent backward, long (~ 65% of Hmax) and slightly convex; DB long (~60% of Lmax) and gently convex; ADB slightly concave at RV, shorter than PDB; ventral part rounded; VB long, convex at LV, concave at RV; AVB and PVB rounded, AVB longer than PVB; carapace slightly postplete to amplete; Lmax below mid-H; dorsal view rhombic with LV’s Wmax in posterior 1/3 of Lmax, in anterior 1/3 at RV.

Remarks

In lateral view, Bairdia jeromei sp. nov. is similar to Orthobairdia sp.1 sensu Crasquin et al., 2010 from the Permian of the Meishan section, Zhejiang Province, South China ( Crasquin et al. 2010) but here the dorsal view clearly precludes the generic attribution to Orthobairdia .

Figures

Fig. 4. Ostracods from the Dajiang section, South China. — A–F. Bairdia? huberti sp. nov. A. Carapace, right lateral view, P6M2939. B. Carapace, right lateral view, P6M2940. C. Paratype, carapace, right lateral view, P6M2941. D. Holotype, carapace, right lateral view, P6M2942. E. Carapace, right lateral view, P6M2943. F. Carapace, right lateral view, P6M2944. — G–P. Bairdia jeromei sp. nov. G. Holotype, carapace, right lateral view, P6M2945. H. Carapace, dorsal view, P6M2946. I. Carapace, right lateral view, P6M2947. J. Paratype, carapace, right lateral view, P6M2948. K. Carapace, right lateral view, P6M2949. L. Carapace, right lateral view, P6M2950. M. Carapace, right lateral view, P6M2951. N. Carapace, right lateral view, P6M2952. O. Carapace, right lateral view, P6M2953. P. Carapace, right lateral view, P6M2954. — Q–T. Bairdia limatusformis Forel, 2010. Q. Carapace, right lateral view, P6M2955. R. Carapace, left lateral view, P6M2956. S. Carapace, sub-dorsal view, P6M2957. T. Carapace, right lateral view, P6M2958. — U–V. Bairdia sp. 1. U. Carapace, right lateral view, P6M2959. V. Carapace, right lateral view, P6M2960. — W–X. Bairdia sp. 2. W. Carapace, dorsal view, P6M2961. X. Carapace, right lateral view, P6M2962. – Scale = 100 µm.

Fig. 6. Height/length diagram of Bairdia jeromei sp. nov.