Athleta (Volutocorbis) eugeniae Vredenburg, 1923

Merle, Didier, Pacaud, Jean-Michel, Métais, Grégoire, Bartolini, Annachiara, Lashari, Rafiq A., Brohi, Imdad A., Solangi, Sarfraz H., Marivaux, Laurent & Welcomme, Jean-Loup, 2014, Volutidae (Mollusca: Gastropoda) of the Lakhra Formation (Earliest Eocene, Sindh, Pakistan): systematics, biostratigraphy and paleobiogeography, Zootaxa 3826 (1), pp. 101-138 : 121

Athleta (Volutocorbis) eugeniae Vredenburg, 1923

( Fig. 8 E–J)

Athleta (Volutocorbis) eugeniae Vredenburg, 1923: 259 , pl. 15, figs 5, 7.

Volutospina sykesi (non Voluta sykesi d’Archiac & Haime, 1853 ). Cossmann & Pissarro, 1909: 23, pl. 2, figs 32–33. Athleta (Volutocorbis) eugeniae . Cotter in Vredenburg 1928: 36.

Volutocorbis eugeniae . Glibert 1960: 49; Ibbal 1972: 63, pl. 18, figs 5–6, pl. 20, figs 10–11 [new combination]. Volutocorbis engeniae . Iqbal 1969: 60 (misspelling of eugeniae ).

Description. Shell biconic, slightly fusiform, H 30–38, D 15–20 mm. Protoconch conical, multispiral, of three whorls. Teleoconch of 5 to 5.5 whorls. Spire moderately high, occupying 18% of total shell height. Spire whorls weakly convex, last whorl oval. Spiral sculpture on spire consisting of first row of subsutural nodules, becoming more developed and slightly spiny on penultimate whorl ( Fig. 8 F); abapically, three rows of nodules including shoulder row, which is weaker than other two. Shoulder row bears spiny nodules on some specimens. On last whorl, spiral sculpture displaying: 1) subsutural row of nodules; 2) shoulder row of nodules spiny on a few specimens, and 3) abapically, 13 rows of nodulose crenulations, becoming less prominent on base. From second to last whorls, costae interrupted by rows of nodules. On last whorl, costae moderately high, cut into prominent, regular, nodulose crenulations by broad spiral grooves. Third whorl: 16 costae; fourth whorl: 13–15 costae; fifth and last whorl: 15–17 costae. Aperture ovate, rather narrow, occupying 55% of total height, 39% of diameter. Inner lip feebly sinuous, columella with one oblique fold succeeded posteriorly by 3 or 4 weak folds; inner lip callus very narrow, not spreading. Outer lip thin, not thickened externally. Siphonal canal slightly elongate; siphonal notch shallow.

Material. 33 spm (stn 4: 3 spm CPAG.RAN. I.28–30, cast MNHN.F.A50366–68 and 30 spm MNHN).

Comments. According to Cossmann & Pissarro (1909) and Vredenburg (1923), Athleta (Volutocorbis) eugeniae is closely similar to A. (Volutocorbis) elevatus (Sowerby, 1840) from the Ypresian of northern Europe, particularly in the spiny shape of the subsutural and shoulder nodules. The European species differs in its other adapical spiral elements including flatter cords separated by narrow spiral grooves, producing an imbricate effect, but lacking nodules. A. (V.) rouaulti Cossmann, 1923 from the late Ypresian of southwestern France superficially resembles A. (V.) elevatus and A. (V.) eugeniae , but can easily be distinguished by its subsutural nodules disappearing progressively during growth.

Stratigraphic range. Lakhra Formation: Jakhmari, Jhirak ( Cossmann & Pissarro 1909; Vredenburg 1923) and Lakhra Dome (this paper).

Figures

FIGURE 8. A – D. Athleta (Volutopupa) citharopsis sp. nov., A – B (holotype, CPAG. RAN. I. 25, ventral (A) and dorsal (B) views, stn 4), C (paratype 1, CPAG. RAN. I. 26, dorsal view, stn 4), D (paratype 2, CPAG. RAN. I. 27, enlarged view of the spire, stn 4); E – J. Athleta (Volutocorbis) eugeniae Vredenburg, 1923, E – F (CPAG. RAN. I. 29, dorsal view (E) and enlarged view of the spire (F), stn 4), G – H (CPAG. RAN. I. 28, dorsal (G) and ventral (H) views, stn 4), I – J (CPAG. RAN. I. 30, dorsal (I) and ventral (J) views, stn 4). Scale bars: A – E, G – J = 10 mm; F = 5 mm.