Hollinella (Hollinella) williamsranchensis Crasquin sp. nov.

urn:lsid:zoobank.org:act: 2A663FBA-1BBF-481E-B29E-1EF99A05F293

Figs 5C, 6I–L

Diagnosis

A species of Hollinella (Hollinella) with a subvertical L 1 in continuation of the ventral lobe and dorsally ended by a small nodule/spine; spine at the posterior part of the velum.

Etymology

After Williams Ranch Member, Bell Canyon Formation, Capitanian, West Texas where this species has been discovered.

Material examined

Holotype USA • right valve, (Fig. 6I); Guadalupe Mountains, West Texas, Williams Ranch Member, Cutoff Formation, Quarry section, sample GM1; Roadian, Middle Permian; MNHN.F. F63391.

Paratype USA • 1 left valve, (Fig. 6K); Guadalupe Mountains, West Texas, Williams Ranch Member, Cutoff Formation, Quarry section, sample GM1; Roadian, Middle Permian; MNHN.F. F63393 .

Additional material

USA • 1 right valve; Guadalupe Mountains, West Texas, Williams Ranch Member, Cutoff Formation, Quarry section, sample GM1; Roadian, Middle Permian; MNHN.F. F63392 • 1 left valve; same locality as for preceding but sample GM4; Roadian, Middle Permian; MNHN.F. F63394 • 2 valves; Guadalupe Mountains, West Texas, Williams Ranch Member, Cutoff Formation, Quarry section, samples GM1, GM4, Roadian; MNHN.F. F63655 • 6 valves; same locality as for preceding; ‘ McKittrick Canyon’ Member, Bell Canyon Formation, MKCS1 section, sample 4 (GM5), Capitanian; Middle Permian; MNHN.F. F63481 .

Dimensions

L= 776–1318 µm; H= 434–773 µm (Fig. 5C).

Description

Carapace auriform and elongate in lateral view; Hmax at ACA; Lmax at mid-L; DB long and straight; presence of cardinal spine at PCA; AB with maximum of curvature at or below mid-H; VB straight; PB with quite large radius of curvature underlined by nodules; presence of a granular velum that ends by posterior spine; L 1 well expressed, vertical and in continuation of ventral lobe, ended dorsally by small nodule/spine; L 2 well expressed, peaked, with small nodule; L 3 covered by nodules, higher than DB; surface granular; intraspecific variations observed in velum formed by small spines (Fig. 6L) and blade (Fig. 6I).

Occurrence

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

Remarks

Hollinella (Hollinella) williamsranchensis sp. nov. is reminiscent of H. warthini Cooper, 1946 from the Missourian–Virgilian (Late Pennsylvanian) of USA (see synthesis in Christopher et al. 1990) by the carapace shape, spines at PCA and posterior part of the velum and the granular surface. However, in H. warthini, L 1 is not visible and L 2 and L 3 are more bulbous. Hollinella (Hollinella) williamsranchensis sp. nov. has the same ornamentation on L 3 as H. (H.) lungcamensis Crasquin, 2018 from the Permian– Triassic boundary of North Vietnam (Crasquin et al. 2018), which is stockier (H/L=0.55–0.65 herein, 0.65–0.75 for H. (H.) lungamensis).