Krotoviini Brunton, Lazarev, and Grant, 1995

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 : 883

Tribe Krotoviini Brunton, Lazarev, and Grant, 1995 Genus Krotovia Fredericks, 1928

Type species: Productus spinulosus Sowerby, 1814 , from the Visean of Great Britain .

Remarks.— Krotovia differs from other genera in the Overtoniinae (e.g., Overtonia , Avonia , and Quasiavonia ), by the lack of strongly developed rugae and lamellae.

Krotovia spinulosa (Sowerby, 1814) Figs. 8P, Q , 9A–E .

1814 Productus spinulosus ; Sowerby 1814: 155, pl. 68: 3.

1862 Productus spinulosus Sowerby, 1814 ; Davidson 1862 a: 175, pl. 34: 18–19.

?1862 Productus granulosus Phillips, 1836 ; Davidson 1862 a: 175, pl. 34: 20–21. (cum syn.)

1914 Pustula spinulosa Sowerby, 1814 ; Thomas 1914: 314, pl. 18: 7–9; pl. 19: 7, non 8. (cum syn.)

non 1943 Krotovia spinulosa (Sowerby, 1814) ; Prendergast 1943: 30, pl. 4: 19–24.

non 1957 Krotovia spinulosa (Sowerby, 1814) ; Coleman 1957: pl. 7: 19–24.

1960 Krotovia spinulosa (Sowerby, 1814) ; Muir-Wood and Cooper 1960: pl. 50: 1–5.

1965 Krotovia spinulosa (Sowerby, 1814) ; Muir-Wood 1965: fig. 340: 2a–d.

?1966 Krotovia spinulosa (Sowerby, 1814) ; Brunton 1966: 224, pl. 12: 1–18; pl. 13: 1–7. (cum syn.)

1989 Krotovia spinulosa (Sowerby, 1814) ; Wilson 1989: fig. 6d.

1991 Krotovia spinulosa (Sowerby, 1814) ; Brunton and Tilsley 1991: 289.

2000 Krotovia spinulosa (Sowerby, 1814) ; Brunton et al. 2000: fig. 287: 1a–e.

Material.—Sixteen articulated shells: MPUM 11884 ( RCC 54- 17b); MPUM 11885 ( RCC 68-2); MPUM 11886 ( RCC 73- 22a); MPUM 11887 ( RCK 15-10); MPUM 11888 ( RCC 1-8f, 23a; RCC 32-5a; RCC 41-10a, 20a; RCC 43-2a, 8a; RCC 73- 8, 11; RCC 85-1b; RCK 15-54; RCK 16-1). Seven dorsal valves: MPUM 11889 ( RCC 3-18); MPUM 11891 ( RCK 15-16); MPUM 11892 ( RCK 15-28); MPUM 11893 ( RCC 10-24; RCC 48-26a, 26b; RCK 15-25). Seven fragments: MPUM 11894 ( RCC 2-18; RCC 12-4; RCC 48-9; RCC 49-29; RCC 68-5; RCC 73-23h; RCK 15-44). All from from mud mound complex of Ricklow Quarry, Monyash, Derbyshire, UK, Monsal Dale Limestone Formation, Brigantian, upper Visean.

Description.—Small, concavo-convex shell with transversely suboval outline; cardinal margin wide; maximum width attained at one-third shell length. Ears small, flat. Corpus cavity shallow. Anterior commissure rectimarginate. Dorsal valve strongly concave. Fold and sulcus absent. Trail long.

Rugae on umbonal slopes and ears and faint ribs on ventral valve. Ventral valve also covered by low, slightly elongated spine bases, quincuncially arranged, four in an area of 10.0 mm 2 at 5.0 mm from umbo. Regularly spaced, small rounded spines on ears aligned parallel to cardinal margin. Dorsal valve with small circular dimples, quincuncially arranged. Both valves covered by dense irregularly concentric growth lines, occasionally poorly developed lamellae.

Remarks.—The specimens are very similar both in outline and ornamentation to the holotype of Krotovia spinulosa from West Lothian ( Scotland), figured by Davidson (1862 a), the specimens figured by Sarycheva and Sokolskaya (1952) from the Moscow Basin and those figured by Muir-Wood and Cooper (1960) from the Mississippian of Cumberland ( England). They differ from the specimens of K. spinulosa described by Brunton (1966) from the Glencar Limestone of County Fermanagh, Ireland (Asbian, upper Visean), as these show strong lamellose ornamentation and should be revised.

Krotovia granulosa ( Phillips, 1836) from the Visean of Great Britain and Ireland was considered as a junior synonym of K. spinulosa by both M’Coy (1844) and Davidson (1862 a). Based on the specimens figured by Davidson (1862 a) from Yorkshire and Scotland, K. granulosa seems to differ from K. spinulosa in having larger, more concentrically arranged pustules.

Stratigraphic and geographic range.— Krotovia spinulosa is recorded from the middle–upper Visean of Great Britain and Ireland (e.g., Sowerby 1814; Davidson 1862 a; Parkinson 1926; Wolfenden 1958; Muir-Wood and Cooper 1960; Brunton 1966; Mitchell 1971; Wilson 1989; Brunton and Tilsley 1991; this study), Germany ( Winkler-Prins and Amler 2006), Urals ( Skompski et al. 2001), the Moscow Basin ( Sarycheva and Sokolskaya 1952), Siberia ( Sarycheva et al. 1963) and Morocco ( Berkhli et al. 2001).

Figures

Fig. 8. Productellidae from the Brigantian (uppermost Visean) of Ricklow Quarry, near Monyash (localities RCC-, RCK-; see Fig. 3) and Wensley Dale, near Matlock (locality WI1; see Fig. 2), Derbyshire, UK. A–E. Alitaria aff. triquetra (Muir-Wood, 1928). A. MPUM11860 (RCC2-13) in anterior view. B. MPUM11861 (RCC12-2) in anterior (B1) and lateral (B2) views. C. MPUM11862 (RCC60-2) in antero-ventral view. D. MPUM11864 (RCC2-40), ventral valve in antero-ventral view.E. MPUM11866 (RCC128-13), dorsal valve in anterior view.F. Eomarginiferina trispina Brunton, 1966, MPUM11869 (WI1- 31) in ventral (F1), dorsal (F2), anterior (F3), and lateral (F4) views. G, H. Overtonia fimbriata (Sowerby, 1824). G. MPUM11870 (RCK15-1b) in ventral G1), dorsal (G2), and lateral (G3) views. H. MPUM11871 (RCK15-53) in ventral (H1) and dorsal (H2) views. I. Avonia sp., MPUM11872 (RCC128-4a), ventral valve in anterior view. J–N. Quasiavonia aculeata (Sowerby, 1814). J. MPUM11873 (RCC32-28a) in anterior view. K. MPUM11874 (RCC49- 28) in anterior (K1), postero-ventral (K2), and lateral (K3) views. L. MPUM11877 (RCC49-24) dorsal valve interior and external cast. M. MPUM11875 RCK17-2) in ventral view. N. MPUM11878 (RCK15-51) dorsal valve interior. O.?Quasiavonia sp., MPUM11883 (RCC3-11); anterior (O1), posterior O2), and lateral (O3) views. P, Q. Krotovia spinulosa (Sowerby, 1814). P. MPUM11884 (RCC54-17b) in ventral view. Q. MPUM11885 (RCC68-2) in ventral (Q1), anterior (Q2), posterior (Q3), and lateral (Q4) views.

Fig. 9. Productellidae and Productidae from the Brigantian (uppermost Visean) of Ricklow Quarry, near Monyash, Derbyshire, UK (localities RCC-, RCK-; see Fig. 3). A–E. Krotovia spinulosa (Sowerby, 1814). A. MPUM11886 (RCC73-22a) in ventral view. B. MPUM11889 (RCC3-18) dorsal valve interior and external cast. C. MPUM11891 (RCK15-16) interior and external cast. D. MPUM11892 (RCK15-28) dorsal valve interior and external cast. E. MPUM11887 (RCK15-10) in ventral view. F–K. Breileenia radiata Brunton in Brunton and Lazarev, 1997. F. MPUM11895 (RCC65-1) in anterior (F1), ventral (F2), and lateral (F3) views. G. MPUM11898 (RCC12-1) dorsal valve external cast. H. MPUM11899 (RCC12-7) dorsal valve interior and external cast. I. MPUM11900 (RCC12-15) dorsal valve external cast. J. MPUM11903 (RCC38A-2) fragment in anterior view. K. MPUM11901 (RCC12-23b) dorsal valve external cast. L. Geniculifera keyserlingiana (De Koninck, 1843), MPUM11905 (RCC73-28) in antero-ventral (L1), lateral (L2), and dorsal (L3) views. M. Limbifera sp., MPUM11890 (RCC54-10b), ventral valve in ventral view. N. Carringtonia cf. carringtoniana (Davidson, 1862a), MPUM11906 (RCC2-51) dorsal valve interior and external cast. O. Productus sp., MPUM11908 (RCC1-61b) in ventral view. P. Productus sp., MPUM11909 (RCC60-6) dorsal valve external cast.