Cryptaulax cf. damboreneae, Ferrari, 2009

Ferrari, S. Mariel, 2009, Cosmopolitan Early Jurassic marine gastropods from west-central Patagonia, Argentina, Acta Palaeontologica Polonica 54 (3), pp. 449-461 : 454-457

Cryptaulax cf. damboreneae sp. nov.

Fig. 3E .

Material.—MLP 18742, MLP 18743, MLP 18744; poorly preserved teleoconch fragments from Cerro Puchenque locality (Mendoza) ( Fig. 1 ), Neuquén Basin, Argentina. Dactylioceras hoelderi Zone , Lower Toarcian, Lower Jurassic.

Description.—Small−sized and high−spired shell, slender and turriculate. Protoconch is not preserved. Teleoconch comprises five whorls with a straight outline. Sutures are deeply incised. Ornament consists of spiral and axial ribs with conspicuous nodes at intersections. Axial ribs are predominant and consists of orthocline to slightly prosocline axial ribs running from suture to suture. Axial ribs are regularly spaced and show no marked change during ontogeny. Seven distinct regularly spaced spiral ribs appear on mature teleoconch whorls (fewer in juvenile growth stages). A second order of spiral ribs is not developed. Basal and apertural features are not preserved.

Remarks.—The present material strongly resembles Cryptaulax damboreneae sp. nov. However, Cryptaulax cf. damboreneae sp. nov. has larger shells, orthocline to slightly opistocline axial ribs, seven stronger spiral ribs intersecting the axial elements, and a weakly developed second order of spiral ribs. The present material probably represents a new Cryptaulax species but the specimens are too poorly preserved for such proposal.

Figures

Fig. 3. Early Jurassic gastropods from Argentina A. Zygopleuridae? gen. et sp. indet., “El Córdoba” fossiliferous locality, Chubut Province. MPEF−PI 1886, latex cast of external mold in lateral view. B–D. Cryptaulax damborenae sp. nov., “El Córdoba” fossiliferous locality, Chubut Province. B. MPEF−PI 1878b, holotype, latex cast of external mold in lateral (B1, B2) and basal (B3) views, ornament detail (B4). C. MPEF−PI 1877, paratype, latex cast of external mold of incomplete teleoconch in apertural view. D. MPEF−PI 1872b, paratype, latex cast of external mold of incomplete teleoconch in lateral view. E. Cryptaulax cf. damboreneae sp. nov., Cerro Puchenque locality, Mendoza Province. MLP 18742, latex cast of external mold of incomplete teleoconch; adult teleoconch in lateral view. F–H. Cryptaulax nulloi sp. nov., “El Córdoba” fossiliferous locality, Chubut Province. F. MPEF−PI 1870, holotype, latex cast of external mold. Adult teleoconch in lateral view (F1), juvenile teleoconch in lateral view (F2). G. MPEF−PI 1861, paratype, latex cast of external mold in lateral and apertural view. H. MPEF−PI 1871, latex cast of external mold of incomplete teleoconch in lateral view (H1), and its ornament detail (H2). Scale bars 1 mm.

Fig. 1. A. Map of the western part of the South American continent showing the localities of new gastropod faunas in Argentina. 1, Cerro Puchenque, Mendoza; 2, Osta Arena Formation area in west−central Patagonia. B. Location map of “El Córdoba” fossiliferous locality (*).