Achatina sculpturata, Neubert & Damme, 2012

Neubert, Eike & Damme, Dirk van, 2012, Palaeogene continental molluscs of Oman, Contributions to Natural History 20, pp. 1-28 : 15-16

Achatina sculpturata sp. nov.

( Fig. 15 )

Type specimens: Holotype NMBE 5018982 ; paratypes NMBE 5018983 – 5018984 .

Type locality: Wadi Darbat , Dhofar, Oman .

Stratum typicum: Paludal biomicritic limestones of the Zalumah Formation.

Age: Late Priabonian.

Material: This species is only known from its type locality.

Etymology: sculpturata refers to the quite unusual (for Achatina ) teleoconch sculpture of this new species.

Diagnosis: A medium sized fossil species of Achatina LAMARCK, 1799 , with a peculiar teleoconch pattern of axial riblets and a sutural cord.

Description: Shell medium sized, fusiform; protoconch comparatively small (only preserved as a stone core); teleoconch of ca. 7 whorls; whorls only slightly rounded, with a sculpture of fine axial ribs running over the complete whorl, ribs usually granular; suture moderately deep, strongly reinforced by a subsutural cord; ribs do not fuse with the cord; aperture obliquely lunulate, narrow, lower part of columella not preserved.

Measurements: Holotype ( Fig. 15a ): H = 66.9 mm; Wh> 7.

Remarks: So far, this species is only recorded from Wadi Darbat, where it occurs sympatrically with Limicolaria omanensis sp. nov. Even juvenile or subadult specimens of both species can be separated by the size of the protoconch (larger in A. sculpturata sp. nov.), the more slender upper teleoconch of L. omanensis sp. nov., and the smaller size of adult specimens. It is quite interesting to see the similarity in the surface sculpture, but the formation of the subsutural cord also helps to differentiate the two species.

This new species is here attributed to Achatina and not Archachatina ALBERS, 1850 because of the relatively small size of the protoconch of A. sculpturata sp. nov.

Figures

Fig. 15a: Achatina sculpturata sp. nov. Wadi Darbat, holotype NMBE 5018982 in frontal view. Figs 15b and 15c show details of the holotype shell; details not to scale.