Athleta (Volutopupa) intercrenatus ( Cossmann & Pissarro, 1909 )

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 : 118-119

Athleta (Volutopupa) intercrenatus ( Cossmann & Pissarro, 1909) comb. nov.

( Fig. 7 E–J)

Volutospina intercrenata Cossmann & Pissarro, 1909: 24 , pl. 2, figs 18–20, pl. 3, figs 1–3.

Description. Shell biconic, H 33–37, D 18–23 mm. Protoconch and first teleoconch whorl unknown; at least 5 teleoconch whorls present. Spire low, occupying 12% of total shell height. Spiral whorls subcarinate, last whorl weakly ventricose. Spiral sculpture on second whorl of one spiral row of small nodules on shoulder angle. From third to fourth whorl, one spiral row of subsutural nodules develops rapidly in addition to shoulder nodules ( Fig. 7 J); one or two small nodules between shoulder and suture. On last whorl, spiral sculpture displaying: 1) adapically two main spiral rows (subsutural and shoulder rows) with one weaker row abapically; 2) between these rows and mid-whorl, weak, poorly marked cords; 3) from mid-whorl to base, ca. 10 flattened cords, producing an imbricate effect. Axial sculpture of collabral costae extending across whorl, interrupted by spiral sculpture. From second whorl to third whorl: 17 costae; fourth whorl: 12–13 costae; fifth and last whorl: 11–12 costae. On last whorl, costae obsolete between adapical rows of nodules, thick and relatively high below shoulder angle, extending across base, becoming almost obsolete towards end of last whorl. Aperture ovate, occupying 61% of total height, 41% of diameter. Inner lip almost straight, columella with 6–10 low folds; inner lip callus very narrow, apparently not spreading far laterally. Outer lip thin, not thickened externally. Siphonal notch not well preserved, apparently weak.

Material. 5 spm (stn 4: 4 spm CPAG.RAN. I.21–24, cast MNHN.F. A50359 –62 and 1 spm MNHN).

Comments. As seen above with Athleta (Volutopupa) noetlingi , the four specimens of V. intercrenata illustrated by Cossmann & Pissarro (1909) are species of Volutopupa and not species of Volutospina . They are not well preserved, except the specimen illustrated in Cossmann & Pissarro’s (1909) pl. 3, fig. 3, which is designated here as the lectotype of Volutospina intercrenata Cossmann & Pissarro, 1909 . Its early teleoconch whorls displays two strong spiral rows of nodules (subsutural and shoulder rows) and its last whorl has 11 thick, relatively high costae, similar to the spire of the adult specimens of A. (V.) intercrenatus collected in the Lakhra Dome. The oval shape of these adults resembles more that of A. (V.) lyra ( Lamarck, 1803) or A. (V.) mutatus (Deshayes, 1835) from the Middle Eocene of the Paris Basin, than it does A. (V.) citharoedus , which displays an inflated and ventricose last whorl. A. (V.) intercrenatus also differs from these species by its strongly developed row of subsutural nodules.

Stratigraphic range. Lakhra Formation: Jhirak ( Cossmann & Pissarro 1909) and Lakhra Dome (this paper).

Figures

FIGURE 7. A – D. Lyrischapa brevispira sp. nov., A – B (paratype 2, CPAG. RAN. I. 20, ventral (A) and dorsal (B) views, stn 4), C – D (paratype 1, CPAG. RAN. I. 19, ventral (C) and dorsal (D) views, stn 4); E – J. Athleta (Volutopupa) intercrenatus (Cossmann & Pissarro, 1909), E – F (CPAG. RAN. I. 22, ventral (E) and dorsal (F) views, stn 4), G (CPAG. RAN. I. 21, ventral view, stn 4), H (CPAG. RAN. I. 23, ventral view, stn 4), I-J (CPAG. RAN. I. 24, ventral view (I) and enlarged view of the spire (J), stn 4). Scale bars: A – I = 10 mm; J = 5 mm.