Middle Permian ostracods (Crustacea) from the Guadalupe Mountains, West Texas, USA Author Tarnac, Anaëlle D9FF2E72-B3F0-4EC7-ADC2-3F04D27E7E1E Centre de Recherches en Paléontologie - Paris, MNHN - SU - CNRS, 8 rue Buffon, 75005 Paris, France. tarnac.anaelle@gmail.com Author Forel, Marie-Béatrice 063C1F7E-6D26-48F9-A8B1-2AFA496B5FB8 Centre de Recherches en Paléontologie - Paris, MNHN - SU - CNRS, 8 rue Buffon, 75005 Paris, France. marie-beatrice.forel@mnhn.fr Author Nestell, Galina 4343960A-89AF-47A7-8418-6B715A7ED791 Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, TX 76019, USA. gnestell@uta.edu Author Nestell, Merlynd 544B3992-191B-4427-B1F7-7A19A9CBCB63 Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, TX 76019, USA. nestell@uta.edu Author Crasquin, Sylvie 6FDDD550-8522-404D-B3A2-D30BFAA86927 Centre de Recherches en Paléontologie - Paris, MNHN - SU - CNRS, 8 rue Buffon, 75005 Paris, France. sylvie.crasquin@mnhn.fr text European Journal of Taxonomy 2021 2021-09-22 770 1 60 http://dx.doi.org/10.5852/ejt.2021.770.1499 journal article 4088 10.5852/ejt.2021.770.1499 003a15e3-4b3f-423c-b40b-7f08fa1b1a75 2118-9773 5536263 33F92DB8-3122-4F8E-995B-DBF260B3E390 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; 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. 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).