UPPER ORDOVICIAN BRACHIOPODS FROM KAZAKHSTAN 



43 



Species included. Leptellina (Mabella) semiovalis Klenina, in 

 Klenina e? a/. 1984: 69, pi. 5, figs. 1,3, 4; pi. 9, figs 4, 7 (^Leptellina 

 (Mabella) obtusa Klenina, in Klenina etal. 1984: 71, pi. 5, figs 5, 6; 

 pi. 6, fig. 2; ^Leptellina (Mabella) incurvata Klenina, in Klenina et 

 al. 1984: 72, pi. 5,fig. 2), Upper Caradoc, beds tb n v of Taldyboi 

 Formation, Chingiz Range, Kazakhstan; Leptellina ? conferta Popov, 

 1985: 56, pi. 2, figs 1-6, Lower Caradoc, Anderken Formation, Chu- 

 Ili Range; Leptelloidea multicostata Rukavishnikova, 1956: 132; 

 Wiradjuriella halis Percival, 1991: 138, fig. 1 2A-Z, Aa-Al, Upper 

 Caradoc, New South Wales, Australia; Leptellina sp., Percival, 1 979b, 

 Ordovician, Goonumbla Volcanics, New South Wales, Australia. 



DISCUSSION. Mabella differs from Leptellina in the distinctive 

 median septum which enlarges anteriorly, and is sometimes bifurcat- 

 ing and tubular. However, Wiradjuriella, from the Caradoc of Australia 

 (Percival 1991), has this same structure as Mabella and can be 

 considered congeneric with it (Cocks & Rong 2000). 



Mabella conferta (Popov, 1985) PI. 5, figs 19-29 



1985 Leptellina! conferta Popov: 56, pi. 2, figs 1-6, text-figs 1 , 2. 

 1991 Wiradjuriella conferta (Popov) Percival: 140. 



Holotype. CNIGR 17/11989, ventral internal mould from the 

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



Material. 35 pairs of conjoined valves, 183 ventral and 66 dorsal 

 valves from Samples 100, 100b, 843, 8128a, 8128b, 8137 (BC 

 56982-84), Anderkenyn-Akchoku section; Sample 761 3, Kujandysai 

 section; Samples 110, 8229, 8230 (BC 57440), 8257, Buldukbai- 

 Akchoku; Sample 8228 (BC 57441, 43^16), east side of Kopalysai 

 River; Samples 818a (BC 57442), 1041a (BC 56978-81), Burultas 

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

 Kotnak Mountains. 



DESCRIPTION. Shell concavoconvex, transverse, semioval in out- 

 line, length about three-quarters of the width, with maximum width 

 at the hinge line. Anterior commissure rectimarginate. Ventral valve 

 strongly convex in transverse and lateral profiles with the maximum 

 thickness slightly posterior to mid-length. Planar strongly apsacline 

 interarea and small, convex pseudodeltidium. Dorsal valve gently 

 concave to almost flat, with a planar, anacline interarea and disjunct 

 chilidial plates. Radial ornament very fine, unequally parvicostellate, 

 with up to five accentuated parvicostellae per 3 mm along the 

 anterior margin of mature specimens. 



Ventral interior with strong teeth lacking dental plates. Cordate 

 muscle field with short, ridge-like adductor scars completely sepa- 

 rating strongly impressed diductor scars. Strong, slightly divergent, 

 saccate mantle canals. Dorsal interior with low, trifid cardinal process 

 facing posteriorly, short socket ridges subparallel to the hinge line. 



Lophophore platform about 90% valve length and 87% as wide as 

 maximum valve width, bordered by a high, ridge-like rim divided 

 medially. High median septum about three-quarters as long as the 

 valve, not joined anteriorly with the subperipheral rim. 



DISCUSSION. This species was originally assigned to Leptellina 

 and later referred by Percival ( 1991 ) to Wiradjuriella. Percival also 

 listed and discussed the differences between the various species of 

 the genus, which is so far known only from Australia and Kazakhstan. 



Genus SHLYGINIA Nikitin & Popov, 1983 



TYPE SPECIES. Shlyginia declivis Nikitin & Popov, 1983, from the 

 Andriushino Formation, Tselnograd Regional Stage (Llandeilo- 

 Lower Caradoc), north-central Kazakhstan. 



Discussion. The affinities of Shlyginia and its differences from 

 Dulankarella were discussed by Nikitin & Popov (1996). 



Table 12 Measurements of complete shells of Shlyginia fragilis 

 (Rukavishnikova) Sample 8228 and 8257 from Kopalysai section. 



Lv 



W 



LAV 



T/L 



N 



16 



16 



16 



16 



16 



X 



10.4 



16.3 



4.2 



64.0% 



40.4% 



s 



1.04 



1.34 



0.54 



6.2 



4.5 



MIN 



8.5 



13.6 



2.9 



50.0% 



31.2% 



MAX 



12.2 



19 



5.1 



72.1% 



51.8% 



Table 13 Measurements of ventral valves of Shlyginia fragilis 

 (Rukavishnikova) Sample 8228 from Kopalysai section. 



Lv 



W 



Ml 



Mw 



LvAV 



M//L Ml/Mw 



N 



6 



6 



6 



6 



6 



6 



6 



X 



9.4 



12.8 



3.6 



4.3 



75.2% 



37.6% 



83.5% 



s 



2.47 



3.61 



1.13 



1.05 



11.2 



4.5 



16.3 



MIN 



5.3 



5.8 



1.8 



2.6 



60.0% 



30.5% 



67.9% 



MAX 



12.8 



15.5 



5.3 



5.6 



91.4% 



41.4% 



110.4% 



Table 14 Measurements of dorsal valves of Shlyginia fragilis 



(Rukavishnikova) Sample 8228 from Kopalysai section and sample 8229 

 from Buldukbai-Akchoku. 





Ld 



W 



SI 



BB1 



BBw 



Ld/W 



Sl/L 



BBwAV 



N 



6 



6 



3 



6 



6 



6 



3 



6 



X 



8.1 



12.1 



5.5 



1.2 



3.8 



67.7% 



79.2% 



31.7% 



s 



1.87 



2.55 



1.25 



0.42 



0.93 



13.2 



8.6 



8.5 



MIN 



6.2 



7.8 



4.3 



0.6 



2.8 



49.7% 



69.4% 



23.6% 



MAX 



10.8 



14.8 



6.8 



1.8 



5.0 



82.1% 



84.4% 



43.6% 



PLATE 5 



Figs 1-3 Dulankarella larga sp. nov. 1, 2, Sample 100, Anderkenyn-Akchoku, BC 57427, ventral exterior and lateral views, x 2. 3, Sample 1041a, 

 Burultas Valley, BC 56513, interareas of conjoined valves, x 8. 



Figs 4, 5 Chonetoidea sp. Sample 8255, Anderkenyn-Akchoku section, BC 56537, external and internal moulds of conjoined valves, x 8. 



Figs 6-18 Kajnaria rugosa sp. nov. 6, unnamed Lower Caradoc formation, about 4 km south-west of Lake Alakul, Sample 816, BC 57438, ventral internal 

 mould, x 1.5. 7-11, 14-16, Sample 100. Anderkenyn-Akchoku; 7-10, BC 57436, conjoined valves, lateral, posterior, ventral and dorsal views, x 2; 11, 14- 

 16, BC 57437, conjoined valves, lateral, posterior, ventral and dorsal views, x 2. 12, 13, 17, 18, Sample 628, west side of Kujandysai River; 12, 13, BC 

 5655 1 , latex cast and dorsal internal mould, holotype, x 2; 17, 18, BC 57439, ventral internal mould, oblique posterior and oblique anterior views, x 2. 



Figs 19-29 Mabella conferta (Popov). 19, 21, 26, 28, 29, Sample 8228, east side of Kopalysai; 19, BC 57445, ventral internal mould, x 3; 21, BC 57443, 

 ventral internal mould, x 4; 26, BC 57444, ventral internal mould, x 4; 28. BC 57446, dorsal exterior, x 4; 29, BC 57441, internal mould of conjoined 

 valves of juvenile specimen, x 4. 20, Sample 8230, Buldukbai-Akchoku section, west side of Kopalysai, BC 57440, latex cast of dorsal interior, x 3. 22— 

 25, Sample 818a, Burultas Valley, BC 57442, conjoined valves, dorsal, posterior, lateral and ventral views, x 4. 27. Sample 7613, Akchoku Mountain, 

 Kujandysai section, CNIGR 20/1 1989, latex cast of dorsal interior of juvenile, x 3. 



Figs 30, 31 Tesikella necopina (Popov, 1980), Kopalysai, Rukavishnikova. 30, Sample 34, BC 56881, ventral internal mould, x 2. 31. Sample 818a, Burultas 

 Valley, BC 57435, x 2.5. 



