Pustula Thomas, 1914

Carniti, Alessandro P., Porta, Giovanna Della, Banks, Vanessa J., Stephenson, Michael H. & Angiolini, Lucia, 2022, Brachiopod fauna from uppermost Visean (Mississippian) mud mounds in Derbyshire, UK, Acta Palaeontologica Polonica 67 (4), pp. 865-915 : 895

Genus Pustula Thomas, 1914

Type species: Producta pustulosa Phillips, 1836 , from the Mississippi- an of Bolland , Yorkshire, England , and Florence Court, Ireland.

Pustula cf. pustulosa ( Phillips, 1836)

Fig. 13B–D .

Material.—Two articulated specimens: MPUM 11987 ( RCC 41-1); MPUM 11988 ( RCC 128-7). One dorsal valve: MPUM 11989 ( RCC 128-17a). Four fragments: MPUM 11990 ( RCC 1-18, 50; RCC 41-10b, 27). All from mud mound complex of Ricklow Quarry, Monyash, Derbyshire, UK, Monsal Dale Limestone Formation, Brigantian, upper Visean.

Description.—Medium-sized, planoconvex shell with subtriangular outline; cardinal margin straight, longer than two-thirds maximum width. Corpus cavity deep. Anterior commissure rectimarginate. Ventral valve regularly convex. Dorsal valve flat.

Ventral valve covered by elongated spine bases in irregular quincunx (10–12 per 5 mm 2) except anteriorly on flanks where they are disposed on staggered rows on low, rounded rugae. Rugae are fainter on the remaining surface of the shell. Dorsal valve ornamented by concentric subrounded rugae, increasing in number by intercalation, three per 5.0 mm length. Slightly elongated dimples, distributed on rugae interspaces or quincuncially arranged (10–15 per 5 mm 2).

Long prominent dorsal median septum.

Remarks.—The specimens are close to Pustula pustolosa by the absence of a sulcus-fold and their ornamentation of slightly elongated spine bases-dimples. They differ from P. pyxidiformis ( De Koninck, 1847) , recorded by Brunton and Tilsley (1991) from the Asbian, upper Visean, of Treak Cliff, Derbyshire, in having regularly concentric rugae and spine bases not extending in length beyond a single ruga.

Figures

Fig. 13. Echinoconchidae, Linoproductidae, Monticuliferidae, Orthotetida, and Orthida from the Brigantian (uppermost Visean) of Ricklow Quarry, near Monyash, Derbyshire, UK (localities RCC-, RCK-; see Fig. 3). A. Echinoconchus punctatus (Sowerby, 1822), MPUM11976 (RCK15-47) in ventral view. B–D. Pustula cf. pustulosa (Phillips, 1836), B. MPUM11989 (RCC128-17a) dorsal valve external cast. C. MPUM11987 (RCC41-1) in ventral view. D. MPUM11988 (RCC128-7) in ventral (D1) and dorsal (D2) views. E, F. Linoprotonia sp. E. MPUM11991 (RCC42-17) in ventral (E1) and lateral E2) views. F. MPUM11992 (RCC60-59) in ventral view. G. Fluctuaria undata (Defrance, 1826), MPUM11926 (RCC300-14) ventral valve in ventral view. H.?Serratocrista aff. dalriensis McIntosh, 1974, MPUM11997 (RCC10-40) ventral valve in ventral view. I. Schellwienella sp., MPUM11995 RCC36-12) ventral valve in ventral view. J, K. Schizophoria (Schizophoria) cf. connivens (Phillips, 1836). J. MPUM12009 (RCC60-48) in ventral view. K. MPUM12010 (RCC1B-7) dorsal valve in dorsal view. L–O. Schizophoria (Schizophoria.) resupinata (Martin, 1809). L. MPUM12003 (RCC1B-4) dorsal valve in dorsal view. M. MPUM11999 (RCC1B-26) in dorsal view. N. MPUM12004 (RCC1B-25) dorsal valve in dorsal view. O. MPUM12005 RCC36-1a) dorsal valve in dorsal view. Scale bars 10 mm.