48 



L.E. POPOV, L.R.M. COCKS AND I.F. NIKITIN 



Limestone ( Upper Caradoc) of Girvan, in having a strongly concavo- 

 convex lateral profile, a cardinal process with up to 8 vertical ridges 

 on the lateral lobes, a shorter median septum and a relatively small 

 lophophore platform extending anteriorly only to the mid-valve. 

 Anoptambonites convexus differs from two somewhat younger 

 Kazakh species, A. subcarinatus Nikitin & Popov (1996:10) from 

 the north Betpak-Dala and A. kovalevskii Popov, Nikitin & Cocks 

 (2000), from the Dulankara Mountains, both from the Dulankara 

 Regional Stage (Upper Caradoc to lowermost Ashgill), in having 

 equally multicostellate radial ornament and a weakly geniculate 

 ventral valve profile, with the maximum height anterior to the mid- 

 valve and near the point of geniculation. It also differs from the 

 former species in having a rectimarginate anterior commissure. 



Anoptambonites orientalis Popov, 1980 PI. 7, figs 1-4, 27 



1980 Anoptambonites orientalis Popov: 149; pi. 2, figs 12-17. 



Holotype. CNIGR 30/11523, dorsal internal mould, from the 

 Anderken Formation, Anderkenyn-Akchoku section, Sample 100b. 



Material. Two pairs of conjoined valves, 14 ventral and 26 dorsal 

 valves from Samples 100b, 8128a (BC 56533, 57476), 8128b, 8137 

 (BC 57478), Anderkenyn-Akchoku section; Sample 8230, 

 Buldukbai-Akchoku section, and Sample 1018, about 7 km south- 

 west of Karpkuduk well, Kotnak Mountains. 



DISCUSSION. Detailed description of this species was provided by 

 Popov (1980). It differs from the contemporaneous Anoptambonites 

 convexus sp. nov. as well as from the somewhat younger A. 

 subcarinatus Nikitin & Popov, 1996 and A. kovalevskii Popov, 

 Nikitin & Cocks, 2000 in having a flattened shell, a carinate ventral 

 valve with gently and evenly convex lateral profile lacking 

 geniculation, a very weakly concave dorsal valve, and in the pres- 

 ence of a small but well-defined pseudodeltidium. The platform in 

 mature specimens of A. orientalis reaches up to 75% of the valve 

 length, whereas in A. convexus and A. kovalevskii it barely exceeds 

 half the valve length. 



Genus KASSINELLA (KASSINELLA) Borissiak, 1956 



Type species. Kassinella globosa Borissiak, 1 956, from the Lower 

 Ashgill Kulunbulak Formation, Tarbagatai Range, Kazakhstan. 



Kassinella (Kassinella)? sp. 



PI. 3, fig. 24 



Material. One dorsal internal mould, BC 56497, from Sample 

 2531, Anderkenyn-Akchoku section. 



Discussion. A single dorsal valve shows the undercut cardinal 

 process and lack of both bema and side septa characteristic of the 

 Hesperomenidae. It possesses an evenly semicircular platform and a 

 median septum not extending anterior of the platform. This evenly 



semicircular platform is unlike most species of Hesperomena, 

 Anoptambonites, Aulie and Chaganella: within the family only 

 Kassinella (Kassinella) has such a platform. However, without 

 knowledge of the ventral interior and the exterior of both valves, 

 generic assignment can only be provisional. Kassinella (Kassinella) 

 is known from the late Caradoc and Ashgill of Kazakhstan, South 

 China. Australia, Scotland, Bohemia and Sweden (Zhan & Cocks 

 1998:36), but if the record from the Anderken Formation is con- 

 firmed then this may be its earliest occurrence. 



Family SOWERBYELLIDAE Opik, 1930 



Subfamily SOWERBYELLINAE Opik, 1930 



Genus SOWERBYELLA (SOWERBYELLA) Jones, 1928 



Type SPECIES. Leptaena sericea J. de C. Sowerby, 1 839, from the 

 Horderley Sandstone (Lower Caradoc) of Shropshire, England. 



Sowerby ella (Sowerby ella) rukavishnikovae Popov, 1980 



PI. 6, figs 7-10 



1980 Sowerbyella rukavishnikovae Popov: 151, pi. 2, figs 1-4. 

 1984 Sowerbyella rukavishnikovae Popov; Nikitin & Popov in 

 Kleninaero/.:150. pi. 16. figs 17-22. 



HOLOTYPE. CNIGR 40/1 1523, a dorsal internal mould from the 

 Anderken Formation, Anderkenyn-Akchoku section, Sample 100b. 



Material. 70 ventral and 133 dorsal valves. Samples 100b (BC 

 56554-5), 848, 8128a, 8128b, 8137, Anderkenyn-Akchoku section; 

 Sample 7613, Kujandysai section; Samples 1 10 (BC 57801), 8229, 

 8230, 8257. Buldukbai-Akchoku; Sample 8228, east side of the 

 Kopalysai River; Sample 1024b, east side of Karatal Valley, near 

 Sorbulak well; Samples 1018, 1018a, 7 km south-west of Karpkuduk 

 well, Kotnak Mountains. 



Discussion. Description, discussion and basic statistics of this 

 species were provided by Popov (1980). Some further specimens 

 from the Anderken Formation are illustrated here. This species is 

 also reported from the upper Bestamak and lower Sargaldak Forma- 

 tions of the Chingiz Range (Nikitin & Popov in Klenina et al. 1984). 



Sowerbyella (Sowerbyella) aff. ampla (Nikitin & Popov, 

 1996) Figs 12.7-12.14 



1986 Anisopleurella sp. Kolobova & Popov: pi. 1, fig. 6. 

 aff. 1996 Anisopleurella ampla Nikitin & Popov: 12, figs 5K-R. 



Material. 14 pairs of conjoined valves. 25 ventral and 8 dorsal 

 valves from Samples 100 (=K98/70), 626, 2531, 8214 (BC 57480), 

 8215, 8223a, 8223b, Anderkenyn-Akchoku section; Samples 628, 

 2538 (BC 57081, 82, 57479, 81, 82), Kujandysai section; Sample 

 948 (BC 57084-85), Tesik River. 



PLATE 7 



Figs 1-4, 27 Anoptambonites orientalis Popov. 1-3, Sample 8 1 28a. Anderkenyn-Akchoku section; 1, BC 56533, latex cast of dorsal interior, x 4; 2, 3, BC 

 57476. ventral internal mould and latex cast, x 2. 4, 27, Sample 8137. Anderkenyn-Akchoku section. BC 57478. latex cast and dorsal internal mould of 

 immature specimen, x 4. 



Figs 5-26 Anoptambonites convexus sp. nov. 5, 6. 9, 10, 18, 20-22, Sample 100, Anderkenyn-Akchoku section; 5, 6, BC 57462. holotype, dorsal internal 

 mould and latex cast, x 2; 9, 10, BC 57464, posterior view of conjoined valves showing interareas, x 1.5 and x 5; 18, BC 57469. ventral exterior, x 2; 20- 

 22, BC 57471, conjoined valves, ventral, lateral and dorsal views, x 2. 7, 8, 11-16, Sample 2538, Akchoku Mountain, Kujandysai section; 7, BC 57461, 

 ventral internal mould, x 3; 8, CNIGR 7/12361, ventral exterior, x 3; 11, 12, BC 57465, latex cast and dorsal internal mould, x 3; 13-16, BC 57463, 

 conjoined valves, dorsal, lateral, ventral and posterior views, x 3. 17, 23-26. Sample 626. Anderkenyn-Akchoku section; 17, BC 57466. ventral internal 

 mould, x 1.5; 23-26, BC 57468, conjoined valves, dorsal, posterior, lateral and ventral views, x 2. 19, Sample 628 (=K- 107/70), west side of Kujandysai, 

 BC 56542, ventral internal mould, x 2. 



