Ceratobairdia mescaleroella Forel, 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 : 34-36

Ceratobairdia mescaleroella Forel sp. nov.

urn:lsid:zoobank.org:act:52B30AEF-EB47-4D12-A0BC-20EC095A2F6F

Figs 5E , 8O–R, 9A–C

Diagnosis

A species of Ceratobairdia with three spines, two long and one short, along the dorsal margin of LV and the ventro-lateral ala not terminated by spine.

Etymology

From the tribe of Mescalero Apaches who inhabited parts of the Southwest US and Northwest Mexico.

Material examined

Holotype

USA • left valve, (Fig. 8O); Guadalupe Mountains , West Texas , ‘ McKittrick Canyon’ Member , Bell Canyon Formation , MKCS1 section, sample 4 (GM5); Capitanian, Middle Permian; MNHN.F. F63433 .

Paratypes

USA • 1 left valve (Fig. 9A); Guadalupe Mountains , West Texas , ‘ McKittrick Canyon’ Member , Bell Canyon Formation , MKCS1 section, sample 4 (GM5); Capitanian, Middle Permian; MNHN.F. F63435 (Fig. 8Q) • 1 right valve; same locality and sample as for preceding; Capitanian , Middle Permian; MNHN.F. F63437 .

Additional material USA • 1 left valve; Guadalupe Mountains , West Texas , ‘ McKittrick Canyon’ Member, Bell Canyon Formation, MKCS1 section, sample 4 (GM5); Capitanian, Middle Permian; MNHN.F. F63434 • 1 left valve; same locality and sample as for preceding; Capitanian, Middle Permian; MNHN.F. F63436 • 1 left valve; same locality as for preceding but sample 2 (GM6); Capitanian, Middle Permian; MNHN.F. F63438 • 1 left valve; same locality and sample as for preceding; Capitanian, Middle Permian; MNHN.F. F63439

Fig. 9 (next page). SEM micrographs of ostracods from the Middle Permian (Roadian, Quarry section, samples GM1; Capitanian, MKCS 1 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–C. Ceratobairdia mescaleroella Forel sp. nov. A. Paratype, A-1, external view of a right valve, sample 4 (GM5) ( MNHN.F. F63437 ). B. External view of a left valve, A-2, sample 2 (GM6) ( MNHN.F. F63438 ). C. External view of a right valve, A-2, sample 2 (GM6) ( MNHN.F. F63439 ). – D–J. Ceratobairdia sexagintaduella Forel sp. nov. D. Holotype, right lateral view of a carapace, adult, sample GM1 ( MNHN.F. F63440 ). E. Paratype, external view of a left valve, adult, sample GM1 ( MNHN.F. F63441 ). F. External view of a left valve, A-1, sample GM1 ( MNHN.F. F63442 ). G. Right lateral view of a carapace, A-2, sample GM1 ( MNHN.F. F63443 ). H. External view of a left valve, A-2, sample GM1 ( MNHN.F. F63444 ). I. Right lateral view of a carapace, A-3, sample GM1 ( MNHN.F. F63445 ). J. External view of a left valve, A-3, sample GM1 ( MNHN.F. F63446 ). – K– R. Ceratobairdia wordensis ( Hamilton, 1942) . K. External view of a left valve, adult, sample GM1 ( MNHN.F. F63447 ). L. External view of a left valve, adult, sample GM1 ( MNHN.F. F63448 ). M. External view of a left valve, A-2?, sample GM1 ( MNHN.F. F63449 ). N. External view of a right valve, sample 4 (GM5) ( MNHN.F. F63450 ). O. External view of a right valve, sample GM1 ( MNHN.F. F63497 ). P. External view of a right valve, sample GM1 ( MNHN.F. F63451 ). Q. External view of a left valve, sample GM1 ( MNHN.F. F63452 ). R. Right lateral view of a carapace, sample 4 (GM5) ( MNHN.F. F63453 ). Scale bars: 100 µm.

• 13 valves; Guadalupe Mountains, West Texas, ‘McKittrick Canyon’ Member, Bell Canyon Formation, MKCS 1 section, samples 4 (GM5) and 2 (GM6); Capitanian, Middle Permian; MNHN.F. F63495 .

Dimensions

See Fig. 5E .

Description

LV: stocky, subtriangular in lateral view with Hmax along DB and Lmax in lower half of H; dorsal margin uniformly arched with concave ADB and PDB, and apex of curvature with 3 equidistant spines; the 3 spines triangular in shape and thickest at base, central spine sub-vertical, external spines biggest, anterior one oriented anteriorly and posterior one oriented posteriorly; AB beak-like located in upper fourth of H with long and subvertical AVB; ventral margin uniformly convex; PB beak-like, located below mid-H; anterior and posterior margins laterally compressed; ventro-lateral ala delimited by smooth subhorizontal ridge lacking terminal spine.

RV: elongate, subtriangular in lateral view with Hmax at AD angulation and Lmax below mid-H; dorsal margin tripartite with DB slightly convex, very concave ADB and PDB; AB beak-like located in upper fourth of H with AVB long and straight; PB beak-like located in lower third of H; ventral margin long and straight except for tenuous oral concavity in anterior part; anterior and posterior margins laterally compressed; lateral surface inflated dorsally into narrow platform and ventrally delimited by lateroventral ala lacking terminal spine and raising upward anteriorly.

Occurrence

Samples 4 (GM5) and 2 (GM6),MKCS1 section, ‘McKittrick Canyon’ Member, Bell Canyon Formation, Guadalupe Mountains, West Texas, USA, Capitanian, Middle Permian (this work).

Remarks

Ceratobairdia dorsospinosa Sohn, 1954 from the Roadian, Middle Permian of Texas ( Sohn 1954) is morphologically very similar to Ceratobairdia mescaleroella sp. nov., but the new species differs by its relatively smaller dimensions, three thicker dorsal spines, lack of a terminal sharp spine at the latero-ventral ridge and PB located higher and more upturned. Sohn (1954) observed that specimens of Ceratobairdia dorsospinosa Sohn, 1954 have one or two spines along the dorsal margin of LV. However, all other characters of the carapaces and valves are very similar, so he suggested that all specimens are conspecific. Although very similar morphologically, Ceratobairdia mescaleroella sp. nov. cannot be considered as another degree in the variability of Ceratobairdia dorsospinosa Sohn, 1954 as the lateral morphologies of the two species are significantly different as detailed above. Contrary to what was shown for Ceratobairdia dorsospinosa Sohn, 1954 , Ceratobairdia mescaleroella sp. nov. has a conservative number and position of dorsal spines, the only difference observed is in the expression of the central spine.

Figures

Fig. 5. Height/length scatter plots of species from the Middle Permian (Roadian, Capitanian) of the Guadalupe Mountains (West Texas, USA). A-1, A-2, A-3. Three last juvenile stages before adult.