Healdia cutoffella 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 : 10-12

Healdia cutoffella Crasquin sp. nov.

urn:lsid:zoobank.org:act:7615C462-45B0-4D0E-A961-7E469B332767

Figs 4D–F , 5A

Diagnosis

A species of Healdia with a short and stocky carapace and a posterior ridge more or less vertical without spines, ADB longer than PDB in both valves.

Etymology

After the Cutoff Formation, Roadian, Middle Permian, West Texas that contains this species.

Material examined

Holotype USA • complete carapace, ( Fig. 4D ); Guadalupe Mountains , West Texas, Williams Ranch Member , Cutoff Formation , Quarry section, sample GM4; Roadian, Middle Permian; MNHN.F. F63368 .

Paratype USA • 1 complete carapace, ( Fig. 4E ); Guadalupe Mountains , West Texas, Williams Ranch Member , Cutoff Formation , Quarry section, sample GM1; Roadian, Middle Permian; MNHN.F. F63369 .

Additional material

USA • 1 left valve, ( Fig. 4F ); Guadalupe Mountains , West Texas, Williams Ranch Member , Cutoff Formation , Quarry section, sample GM4; Roadian, Middle Permian; MNHN.F. F63370 • 10 complete carapaces, 32 valves; Guadalupe Mountains , West Texas, Williams Ranch Member , Cutoff Formation , Quarry section, samples GM1, GM4; Roadian, Middle Permian; MNHN.F. F63474 .

Dimensions

L= 452–667 µm; H =300–448 µm ( Fig. 5A )

Description

Short and stocky carapace, egg-shaped in lateral view; LV strongly overlaps RV all around the carapace; ADB longer than PDB at both valves; AB large with maximum of curvature located around mid-H;

PB quite equivalent to AB; presence of a posterior vertical to slightly tilted ridge, without spines; carapace laterally compressed posterior to ridge, more strongly at LV.

Occurrence

Samples GM1, GM4, Quarry section, Williams Ranch Member, Cutoff Formation, Roadian; sample 4 (GM5), MKCS1 section, ‘McKittrick Canyon’ Member, Bell Canyon Formation, Capitanian; Middle Permian, Guadalupe Mountains, West Texas, USA (this work).

Remarks

Healdia cutoffella sp. nov. is very similar to Healdia simplissima Harlton, 1933 from the Pennsylvanian of Texas and Oklahoma ( Harlton 1933; Hoare & Merrill 2004). Both species have the same ridge without spines, equivalent AB and PB, but mainly differ by PB being longer than AB in H. simplissima (herein AB is longer than PB).

Figures

Fig. 4 (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 sample 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. Healdia mckittrickensis Crasquin sp. nov. A. Holotype, right lateral view of a carapace, sample 4 (GM5) (MNHN.F.F63365). B. Paratype, right lateral view of a carapace, sample GM1 (MNHN.F.F63366). C. External view of a right valve, sample 4 (GM5) (MNHN.F.F63367). – D–F. Healdia cutoffella Crasquin sp. nov. D. Holotype, right lateral view of a carapace, sample GM4 (MNHN.F.F63368). E. Paratype, external view of a left valve, sample GM1 (MNHN.F.F63369). F. External view of a left valve, sample GM4 (MNHN.F.F63370). –G–I. Sulcella mesopermiana Kozur, 1991.G. External view of a left valve, sample GM1 (MNHN.F.F63371). H. Left lateral view of a carapace, sample 2 (GM6) (MNHN.F.F63372). I. External view of a left valve, sample GM2 (MNHN.F.F63373). – J. Kirkbyidae gen. et sp. indet., right lateral view of a carapace, sample 4 (GM5) (MNHN.F.F63374). – K–L. Amphissites centronotus (Ulrich & Bassler, 1906).K. External view of a right valve, sample GM1 (MNHN.F.F63375).L. External view of a right valve, sample GM1 (MNHN.F.F63376). – M. Polytylites? sp., external view of a left valve, sample GM4 (MNHN.F.F63377). – N. Kindlella fissiloba Sohn, 1954, external view of a right valve, sample GM1 (MNHN.F.F63378). – O. Kindlella sp., external view of a left valve, sample GM1 (MNHN.F.F63379). – P–Q. Kindlella bellsundi Olempska & Błaszyk, 1996. P. External view of a right valve, sample 4 (GM5) (MNHN.F.F63380). Q. External view of a right valve, sample 4 (GM5) (MNHN.F.F63381) – R. Kirkbya sp., external view of a right valve, sample GM1 (MNHN.F.F63382). Scale bars: 100 µm.

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.