. Bulletin of the British Museum (Natural History), Geology. MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 145 Meiourogonyaulax valensii sp. nov. PL 15, fig. 7 ; Text-fig. 37 1953. Gonyaulax sp. indet., Valensi : 27, pi. 2, figs. 12, 13. Derivation of name. Named after Lionel Valensi, who published the first full descriptions of Middle Jurassic dinoflagellate/acritarch assemblages. Diagnosis. A Meiourogonyaulax having a broadly ellipsoidal theca ; lacking apex in all specimens seen. Tabulation ?4', oa, 6", 6c, 6'", ip, i , i"". Crests of moderate height, slightly striated
. Bulletin of the British Museum (Natural History), Geology. MESOZOIC AND CAINOZOIC DINOFLAGELLATE CYSTS 145 Meiourogonyaulax valensii sp. nov. PL 15, fig. 7 ; Text-fig. 37 1953. Gonyaulax sp. indet., Valensi : 27, pi. 2, figs. 12, 13. Derivation of name. Named after Lionel Valensi, who published the first full descriptions of Middle Jurassic dinoflagellate/acritarch assemblages. Diagnosis. A Meiourogonyaulax having a broadly ellipsoidal theca ; lacking apex in all specimens seen. Tabulation ?4', oa, 6", 6c, 6'", ip, i , i"". Crests of moderate height, slightly striated and irregularly perforate, with smooth or finely denticulate distal edges. Spines present at some crest nodes. Cingulum strongly spiral, relatively broad ; sulcus broadening posteriorly, subdivided by low ridges. Shell surface punctate or alveolar. HoLOTYPE. Specimen (L. Valensi preparation), Laboratoire de Micro- paleontologie, Ecole Pratique des Hautes Etudes, Paris. Chert from Airvault, Poitou, France. Middle Jurassic (Bathonian). Dimensions. Holotype : overall length yoyi, breadth 70[x ; shell length, approx. 6o[jL, breadth approx. 50[jl ; width of transverse furrow [x. Description. Although this species is based on Valensi's single specimen, the author has also seen a number of specimens in material from the Bathonian of the Aquitaine Basin, unfortunately not available for Fig. 37. Meiourogonyaulax valensii sp. nov. Tabulation. Left, ventral view- right, dorsal view. x c. 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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