Denticupachydomella bellcanyonensis 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 : 45-46

Denticupachydomella bellcanyonensis Forel sp. nov.

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Fig 5H , 11P–Q

Diagnosis

A species of Denticupachydomella with a row of nodules uniform in size along DB of LV and a surface ornamented by nodules.

Etymology

After the Bell Canyon Formation (Middle Permian, West Texas) that yielded this new species.

Material examined

Holotype USA • complete carapace, ( Fig. 11P ); Guadalupe Mountains , West Texas, ‘ McKittrick Canyon’ Member , Bell Canyon Formation , MKCS1 section, sample 4 (GM5); Capitanian, Middle Permian; MNHN.F. F63469 .

Paratype USA • 1 left valve, ( Fig. 11Q ); Guadalupe Mountains , West Texas, ‘ McKittrick Canyon’ Member , Bell Canyon Formation , MKCS1 section, sample 2 (GM6); Capitanian, Middle Permian; MNHN.F. F63470 .

Additional material

USA • 1 complete carapace, 13 valves; Guadalupe Mountains , West Texas, ‘ McKittrick Canyon’ Member , Bell Canyon Formation , MKCS1 section, samples 4 (GM5) and 2 (GM6); Capitanian, Middle Permian; MNHN.F. F63500 .

Dimensions

L= 387–756 µm; H =247–433 µm ( Fig. 5H ).

Description

Small carapace sub-rectangular, H/L=0.57–0.69; DB straight on both valves; row of nodules long DB of LV; AB with quite large radius of curvature with maximum located below mid-H; VB almost straight at both valves; PB with large radius of curvature for genus with maximum of curvature located in lower part of H; presence of spine in posteroventral part of carapace; overlap of LV on RV all around carapace; presence of nodules on surface of both valves.

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

Denticupachydomella bellcanyonensis sp. nov. is very similar to the type species Denticupachydomella spinosa Yuan in Yuan et al., 2009 from the Changhsingian of South China ( Yuan et al. 2009) but is larger and lacks the two horny spines at the anterior and posterior cardinal angles. Denticupachydomella bellcanyonensis sp. nov. differs from Denticupachydomella multinodosa (Forel in Crasquin et al. 2010) from the Changhsingian (Late Permian) of Sichuan, south-west China ( Crasquin et al. 2010) by the presence of a postero-ventral spine and by the organisation of nodules along dorsal and ventral margins at both valves. Herein, the dorso-central shoulder at RV is absent and the surface is covered by nodules. The species from the Late Capitanian of the Penglaitan section (Guadalupuan–Lopingian GSSP) in Guangxi, South China ( Zazzali 2016: fig. 13o–p, unpublished material) differs from Denticupachydomella bellcanyonensis sp. nov. by a more elongate carapace and a PB with smaller radius of curvature. The species from the Penglaitan section is also new and has to be described.

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.

Fig. 11 (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), except R and S from the late Capitanian, Middle Permian, Penglaitan section, Guangxi, South China (Zazzali 2016, unpublished PhD thesis). All specimens from A–Q are temporarily housed in the collections of the Muséum national d’histoire naturelle, Paris, France (MNHN), specimens R and S are housed in the collections of the Sorbonne University, Paris, France. A–B. Ceratobairdia cf. ventrocostata Wang, 1978. A. External view of a left valve, sample 4 (GM5) (MNHN.F.F63454). B. External view of a left valve, sample 2 (GM6) (MNHN.F.F63455). – C–G. Ceratobairdia pratti Forel sp. nov. C. Holotype, right lateral view of a carapace, sample GM1 (MNHN.F.F63456). D. Paratype, external view of a left valve, sample GM1 (MNHN.F.F63457). E. External view of a left valve, sample GM1 (MNHN.F.F63458). F. External view of a left valve, sample GM1 (MNHN.F.F63459). G. External view of a left valve, sample GM1 (MNHN.F.F63460). – H–I. Petasobairdia campbelli Chitnarin in Chitnarin et al., 2017. H. External view of a left valve, sample GM2 (MNHN.F.F63461). I. External view of a left valve, sample GM4 (MNHN.F.F63462). – J. Petasobairdia cf. bicornuta Chen in Chen & Shi, 1982, right lateral view of a carapace, sample 4 (GM5) (MNHN.F.F63463). – K. Petasobairdia? sp., external view of a right valve, sample 4 (GM5) (MNHN.F.F63464). – L. Microcheilinella postspinosa Chen, 1958, right lateral view of a carapace, sample 2 (GM6) (MNHN.F.F63465). – M. Microcheilinella sp. 15 in Zazzali et al. (2015), right lateral view of a carapace, sample 4 (GM5) (MNHN.F.F63466). – N–O. Microcheilinella sp. N. Right lateral view of a carapace, sample 2 (GM6) (MNHN.F.F63467). O. Right lateral view of a carapace, sample 4 (GM5) (MNHN.F.F63468). – P–Q. Denticupachydomella bellcanyonensis Forel sp. nov. P. Holotype, right lateral view of a carapace, sample 4 (GM5) (MNHN.F.F63469). Q. Paratype, external left of a right valve, sample 2 (GM6) (MNHN.F.F63470). – R–S. Microcheilinella sp. D in Zazzali (2016). R. Dorsal view of a carapace (P6M 3778). S. Right lateral view of a carapace (P6M 3779). Scale bars: 100 µm.