Geisina culbersonensis Crasquin, 2021

Tarnac, Anaëlle, Forel, Marie-Béatrice, Nestell, Galina, Nestell, Merlynd & Crasquin, Sylvie, 2021, Middle Permian ostracods (Crustacea) from the Guadalupe Mountains, West Texas, USA, European Journal of Taxonomy 770, pp. 1-60 : 22-23

Geisina culbersonensis Crasquin sp. nov.

urn:lsid:zoobank.org:act:FA68573E-E0FA-4DC1-B82E-6F860628863F

Fig. 6N–P

Diagnosis

A species of Geisina with a pustulose carapace, two large spines in the posterior part of the carapace and free margins bordered with small spines.

Etymology

From Culberson County, West Texas, USA, where the studied samples have been collected.

Material examined

Holotype USA • complete carapace, ( Fig. 6N ); Guadalupe Mountains , West Texas, Williams Ranch Member , Cutoff Formation , Quarry section, sample GM1; Roadian, Middle Permian; MNHN.F. F63396 .

Paratype USA • 1 complete carapace, ( Fig. 6O ); Guadalupe Mountains , West Texas, Williams Ranch Member , Cutoff Formation , Quarry section, sample GM1; Roadian, Middle Permian; MNHN.F. F63397 .

Additional material

USA • 1 complete carapace; Guadalupe Mountains , West Texas, Williams Ranch Member , Cutoff Formation , Quarry section, sample GM2; Roadian, Middle Permian; MNHN.F. F63398 • 1 complete carapace, 4 valves; Guadalupe Mountains , West Texas, Williams Ranch Member , Cutoff Formation , Quarry section, samples GM1, GM2, GM4; Roadian, Middle Permian; MNHN.F. F63483 .

Dimensions

L= 602–676 μm; H =430–548 μm; H/L=0.53–0.64.

Description Carapace sub-rectangular in lateral view with Hmax in anterior ⅓rd of L and Lmax slightly below mid-H; DB long and straight; ACA=115°–130°, PCA=105°–115°; AB with large radius of curvature with maximum at lower ⅓ rd H; VB nearly straight; PB laterally compressed, large with maximum of curvature located at mid-H; free margins bordered by small spines; L 2 not well visible; S 2 round and clearly marked; L 3 underlined by two large spines, one dorsal and one medio-ventral, pointing upward; surface completely covered with pustules.

Occurrence

Samples GM1, GM2, GM4, Quarry section, Williams Ranch Member, Cutoff Formation, Guadalupe Mountains, Western Texas, USA, Roadian, Middle Permian (this work).

Remarks

Geisina culbersonensis sp. nov. has a very particular shape and primary ornamentation. It can be compared with Geisina sp. in Chitnarin et al. 2012 from the Asselian–Sakmarian, Early Permian of Thailand ( Chitnarin et al. 2012), which has a smaller PB and a smooth surface.

Figures

Fig. 6 (next page). SEM micrographs of ostracods from the Middle Permian (Roadian, Quarry section, samples GM1, GM2, and GM4; Capitanian, MKCS1 section, samples 4 (GM5) and 2 (GM6)) of the Guadalupe Mountains (West Texas, USA).All specimens are temporarily housed in the collections of the Muséum national d’histoire naturelle, Paris, France (MNHN). A–B. Aurikirkbya guadalupensis Crasquin sp. nov. A. Holotype, left lateral view of a carapace, sample GM2 (MNHN.F.F63383). B. Paratype, left lateral view of a carapace, sample GM1 (MNHN.F.F63384). – C, E. Aurikirkbya wordensis (Hamilton, 1942). C. External view of a left valve, sample 2 (GM6) (MNHN.F.F63385). E. External view of a left valve, sample GM4 (MNHN.F.F63387). – D. Kirkbyella (Berdanella) cf. quadrata Croneis & Gutke, 1939, external view of a right valve, sample 4 (GM5) (MNHN.F.F63386). – F–H. Roundyella lebaensis Krömmelbein, 1958. F. External view of a left valve, sample GM4 (MNHN.F.F63388). G. External view of a right valve, sample GM4 (MNHN.F.F63389). H. External view of a right valve, sample GM1 (MNHN.F.F63390). – I–L. Hollinella (Hollinella) williamsranchensis Crasquin sp. nov. I. Holotype, external view of a right valve, sample GM1 (MNHN.F.F63391).J. External view of a right valve, sample GM1 (MNHN.F.F63392). K. Paratype, external view of a left valve, sample GM1 (MNHN.F.F63393). L. External view of a left valve, sample GM4 (MNHN.F.F63394). – M. Glyptopleura sp., external view of a right valve, sample GM1 (MNHN.F.F63395). – N–P. Geisina culbersonensis Crasquin sp. nov. N. Holotype, external view of a right valve, sample GM1 (MNHN.F.F63396). O. Paratype, external view of a right valve, sample GM1 (MNHN.F.F63397). P. External view of a left valve, sample GM2 (MNHN.F.F63398). – Q–R. Miltonella cf. shupei Sohn, 1950. Q. External view of a left valve, sample 4 (GM5) (MNHN.F.F63399). R. External view of a left valve, sample 4 (GM5) (MNHN.F.F63400). Scale bars: 100 µm.