Acratia candyae, 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 : 6-7

Acratia candyae sp. nov.

Fig. 3 A-D

Diagnosis

Species of Acratia similar to Microcheilinella in dorsal view, with LV larger than RV and AB broadly rounded in 1/4 circle.

Etymology

Personal dedication to Candy Boiteux.

Material examined

Holotype

One carapace ( Fig. 3A ), Dajiang section, sample 05PAJ28, collection number P6M2917.

Paratype

One carapace ( Fig. 3C ), Dajiang section, sample 05PAJ17, collection number P6M2919.

Other material

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

Type locality

Wujiaping Formation (Samples 05PAJ17, 25, 28, 29), Dajiang section (25°33’56’’N- 106°39’41’’E), Guizhou Province, South China, Changhsingian, Late Permian.

Measurements

L = 323 – 464 μm; H = 140 – 200 μm; H/L = 0.43 – 0.44.

Description

Carapace elongated and subovoid in lateral view; surface smooth; carapace slightly preplete to amplete; LV strongly overlaps RV all around the carapace; Lmax below mid-H; dorsum long and slightly rounded in both valves, angles between PDB and DB not distinct; rounded angle between DB and ADB (~140°); PDB short and steep; DB long and gently bent backward; ADB short, steep and convex; ventral margin flat and straight at both valves;AVB, VB, PVB not distinct; AVB straight and slightly bent toward AB; AB broadly rounded in 1/4 circle; acratian beak clear but not pronounced, located at VB; PB sharpen with quite large radius of curvature for the genus, maximum slightly below mid-H; angle between AVB-AB (>90°) larger than angle between PVB-PB (<90°); dorsal view similar to the one of the genus Microcheilinella with carapace thick and Wmax located in the posterior 1/3 of L, hinge line slightly incised.

Through the ontogeny, the carapace becomes more stocky, more amplete at RV, with DB shorter and more rounded.

Remarks

The strong overlap of LV on RV all around the carapace and characteristics of dorsal view are reminiscent of the genus Microcheilinella . However the acratian beak clearly precludes Microcheilinella attribution and indicates the genus Acratia . Acratia candyae sp. nov. is very close to Acratia sp.2 sensu Crasquin, 2008 from the Late Permian of Dolomites ( Crasquin et al. 2008). However, Acratia sp.2 sensu Crasquin, 2008 has longer ADB and well expressed angles between PDB, DB and ADB.

Figures

Fig. 3. Ostracods from the Dajiang section, South China. — A–D. Acratia candyae sp. nov. A. Holotype, carapace, right lateral view, P6M2917. B. Carapace, dorsal view, P6M2918. C. Paratype, carapace, right lateral view, P6M2919. D. Carapace, right lateral view, P6M2920. — E–F. Acratia subfusiformis Wang, 1978. E. Carapace, right lateral view, P6M2921. F. Carapace, right lateral view, P6M2922. — G. Acratia? sp. 1, carapace, right lateral view, P6M2923. — H. Acratia? sp. 2, carapace, right lateral view, P6M2924. — I. Acratia? sp. 3, carapace, right lateral view, P6M2925. — J–K. Acratia sp. 4. J. Carapace, left lateral view, P6M2926. K. Carapace, right lateral view, P6M2927. — L. Acratia sp. 5, carapace, right lateral view, P6M2928. — M. Acratiidae indet., carapace, right lateral view, P6M2929. — N–Q. Bairdia adelineae sp. nov. N. Holotype, carapace, right lateral view, P6M2930. O. Carapace, dorsal view, P6M2931. P. paratype, carapace, right lateral view, P6M2932. Q. Carapace, right lateral view, P6M2933. — R–V. Bairdia gaelleae Crasquin, 2010. R. Carapace, dorsal view, P6M2934. S. Carapace, right lateral view, P6M2935. T. Carapace, left lateral view, P6M2936. U. Carapace, right lateral view, P6M2937. V. Carapace, right lateral view, P6M2938. – Scale = 100 µm.