Reticularia cf. mesoloba ( Phillips, 1836 )

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 : 906-907

Reticularia cf. mesoloba ( Phillips, 1836)

Fig. 16G .

Material.—One articulated specimen: MPUM12053 (RCK15-43). One fragment: MPUM11946 (RCC60-41). Both from mud mound complex of Ricklow Quarry, Monyash, Derbyshire, UK, Monsal Dale Limestone Formation, Brigantian, upper Visean.

Description.—Small, ventribiconvex shell with suboval outline; cardinal margin straight, maximum width attained at shell mid-length. Anterior commissure rectimarginate. Rounded ventral sulcus developing from shell mid-length. Dorsal umbo straight; interarea orthocline. Both valves covered by subimbricated lamellae, numbering 40 in 5.0 mm length posteriorly, to 25 in 5.0 mm anteriorly. Dental plates divergent.

Remarks.—The specimens are close to Reticularia mesoloba , from the Mississippian of Bolland, Yorkshire, England ( George 1932), based on its morphology, the presence of dental plates and dense lamellose ornamentation. George (1932) described the species as reaching 30.0 mm in length and with feeble fold-sulcus anteriorly; the specimens may then represent juveniles.

Figures

Fig. 16. Spiriferida and Spiriferinida from the Brigantian (uppermost Visean) of Ricklow Quarry, near Monyash (localities RCC-, RCK-; Fig. 3) and Wensley Dale, near Matlock (locality WI1; Fig. 2), Derbyshire, UK. A. Latibrachythyris cf. crassa (De Koninck, 1843), MPUM12040 (RCC54- 10a) ventral valve in ventral (A1) and lateral (A2) views. B–D. Latibrachythyris rotundata (Sowerby, 1825). B. MPUM12047 (RCC65G-12) dorsal valve in dorsal view. C. MPUM12043 (RCK15-1a) in ventral view. D. MPUM12045 (RCK15-40) ventral valve in ventral (D1) and lateral (D2) views. E, F. Brachythyrididae gen. et sp. indet. E. MPUM12049 (RCC11-8) ventral valve in ventral view. F. MPUM12052 (RCC42-5a) dorsal valve in dorsal view. G. Reticularia cf. mesoloba (Phillips, 1836), MPUM12053 (RCK15-43) in ventral (G1) and dorsal (G2) views. H. Georgethyris lobata (Muir- Wood, 1926), MPUM12086 (WI1-9) in ventral (H1), dorsal (H2), anterior (H3) and lateral (H4) views. I–K. Phricodothyris paricosta George, 1932.. MPUM12058 (RCK15-34a) dorsal valve (I1) and MPUM12055 (RCK15-34b) ventral valve (I2). J. MPUM12057 (RCK15-9) dorsal valve in dorsal view. K. MPUM12054 (RCC40-10a) ventral valve in ventral view. L–N. Phricodothyris cf. periculosa George, 1932. L. MPUM12061 (RCK15-3) in dorsal (L1) and lateral (L2) views. M. MPUM12060 (RCC73-30a) in ventral (M1) and lateral (M2) views. N. MPUM12064 (RCC2-37) ventral valve in ventral view. O. Phricodothyris sp., MPUM12071 (RCC60-4a) ventral valve in ventral view. P. Nebenothyris sp., MPUM12073 (WI1-26a) ventral valve in ventral view. Q.?Punctospirifer sp., MPUM12074 (RCC73-23c) ventral valve in ventral view. Scale bars 10 mm.