. Bulletin of the British Museum (Natural History), Geology. . I 0-125mm Ml Fig. ioa-c. Amicytheridea ihopyensis (Grekoff). a, b. Anterior and posterior duplicative, female right valve, to show marginal pore canals, c. Muscle scars, male left valve exterior, fig. 13), length 0-52 mm ; height 0-34 mm ; width 0-38 mm. , male left valve (Text-fig. 10c), length 0-62 mm ; height 0-33 mm. Amicytheridea triangulata sp. nov. PL 7, figs 14-16 ; Text-fig. na-c 1963 Procytheridea ? 3330 Grekoff : 1749, pi. 6, figs 173-5. Diagnosis. Amicytheridea with positive triangular ornamenta
. Bulletin of the British Museum (Natural History), Geology. . I 0-125mm Ml Fig. ioa-c. Amicytheridea ihopyensis (Grekoff). a, b. Anterior and posterior duplicative, female right valve, to show marginal pore canals, c. Muscle scars, male left valve exterior, fig. 13), length 0-52 mm ; height 0-34 mm ; width 0-38 mm. , male left valve (Text-fig. 10c), length 0-62 mm ; height 0-33 mm. Amicytheridea triangulata sp. nov. PL 7, figs 14-16 ; Text-fig. na-c 1963 Procytheridea ? 3330 Grekoff : 1749, pi. 6, figs 173-5. Diagnosis. Amicytheridea with positive triangular ornamentation of ridges con- nected across interspaces by minor ridges. Holotype. , female left valve, sample B97 (PL 7, fig. 16). Paratypes. and , sample B97. Horizon and Locality. Middle Callovian, sample B97, Mandawa Anticline (Text-fig. 3). Description. Carapace distinctly dimorphic, males very positively tapering to posterior end. Left valve larger than right. Ornamentation striking - a tri- angular arrangement of ridges with minor connecting ridges. Anterior marginal border distinct. Oblique antero-dorsal furrow clearly marked; postero-dorsal furrow present in female. Hinge lobodont, antero-median element loculate in right valve (Text-fig. 11a). Duplicature broad, without a vestibule. Marginal pore canals not clearly seen but in one specimen (Text-fig. 11b) straight, splayed out and few in number (8 observed anteriorly). Muscle scars not Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original British Museum (Natural History). London : BM(NH)
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