Pugilis cf. kilbridensis ( Muir-Wood, 1928 )

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 : 890-891

Pugilis cf. kilbridensis ( Muir-Wood, 1928)

Fig. 11I–K .

Material.—Two ventral valves: MPUM11954 (RCC2-47); MPUM11955 (RCC54-4). One dorsal valve: MPUM11956 (RCC128-3). One fragment: MPUM11957 (RCC128-28b). All from mud mound complex of Ricklow Quarry, Monyash, Derbyshire, UK, Monsal Dale Limestone Formation, Brigantian, upper Visean.

Description.—Medium-sized, elongated concavo-convex shell with suboval outline; cardinal margin corresponding to maximum width. Both valves geniculated. Corpus cavity deep. Anterior commissure rectimarginate. Ventral valve enrolled, visceral disc convex; geniculation angle 90°. Trail long, tubiform, straight. Dorsal visceral disc flat; geniculation angle 70°. Trail long, straight.

Ornamentation consists of subrounded ribs with narrow interspaces. Ribs increase in number anteriorly by bifurcation. They number 17 per 10.0 mm at geniculation and trail. Low, rounded rugae on visceral discs, six per 5.0 mm length, resulting in a reticulate ornamentation. Small spines scattered over the ventral visceral disc, on ribs.

Remarks.—The specimens are similar to Productus kilbridensis from the Brigantian, uppermost Visean, of Kilbride (Ayrshire, Scotland), figured by Muir-Wood (1928: pl. 7: 5a–c). The specimens are also close to P. scotica (Sowerby, 1814) , from the upper Visean of England and Scotland, in their ornamentation, but they differ from it in having a longer, straight trail, a strongly geniculated dorsal valve and in lacking a sulcus ( Muir-Wood 1928).

Figures

Fig. 11. Productidae from the Brigantian (uppermost Visean) of Ricklow Quarry, near Monyash, Derbyshire, UK (localities RCC-, RCK-; Fig. 3). A–F. Antiquatonia insculpta (Muir-Wood, 1928). A. MPUM11938 (RCC1B-9) in anterior (A1) and lateral (A2) views. B. MPUM11939 (RCC3-15a) in antero-ventral view. C. MPUM11940 (RCC42-26) in antero-ventral view. D. MPUM11941 (RCC110-1b) in lateral view. E. MPUM11944 (RCC2-25) ventral valve in ventral view. F. MPUM11947 (RCC128-2) dorsal valve interior and external cast. G, H. Dictyoclostus pinguis (Muir-Wood, 1928). G. MPUM11950 (RCC54-11) ventral valve in ventral view. H. MPUM11951 (RCK15-63a) dorsal valve external cast. I–K. Pugilis cf. kilbridensis (Muir-Wood, 1928). I. MPUM11956 (RCC128-3) dorsal valve interior and external cast. J. MPUM11955 (RCC54-4) ventral valve in anterior (J1) and lateral (J2) views. K. MPUM11954 (RCC2-47) ventral valve in anterior view. L. Pugilis cf. scotica (Sowerby, 1814), MPUM11958 (RCC2-41) in lateral (L1), ventral (L2), and anterior (L3) views. M, N. Buxtonia scabricula (Sowerby, 1814). M. MPUM11959 (RCC1B-13) in ventral view. N. MPUM11960 (RCC35A-11a) in ventral view.