Caecum inhacaense, Albano & Pizzini, 2011

Albano, Paolo G. & Pizzini, Mauro, 2011, Notes on Caecidae (Mollusca: Gastropoda) from southern Mozambique, with the description of a new species, African Invertebrates 52 (1), pp. 1-1 : 5-6

Caecum inhacaense sp. n.

Figs 3A–C, E

Etymology: From Ilha da Inhaca, southern Mozambique, the type locality.

Description:

7XEH F\OLQGULFDO, VPRRWK, FURVVHG RQO\ E\ ¿QH JURZWK VWULDWLRQ. 6HSWXP PXFURQDWH, turned to right side by about 30° and protruding over the cutting plane. Mucro ( Fig.3C ) KDV WKH IRUP RI D VPDOO ÀDWWHQHG EDOO, DOPRVW REVROHWH LQ MXYHQLOH VSHFLPHQV. 'RUVDO PDUJLQ RI PXFUR VWURQJO\ FRQYH[, ZKLOH LWV YHQWUDO PDUJLQ VOLJKWO\ 6‒VKDSHG DQG LQÀDWHG near the cutting plane.Aperture circular, weakly ringed and slightly contracted. Juveniles ( Fig. 3E ) have more slender shell, and aperture lip thin and fragile. Colour whitish.

Operculum and soft parts morphology unknown.

Holotype dimensions: length 1.4 mm, diameter 0.3 mm.

Holotype ( Figs 3A–C ): Loc. 2035; gold coated for SEM photography ( MZB 15000 ).

Paratypes:A (juvenile) from the type locality( Fig.3E ), gold coated for SEM photography ( MZB 15001 ) . B from Loc. 2036 ( MNHN 23121 ) . C from Loc. 2036 ( NMSA L8452 /T2659).D from Loc. 2036 ( BMNH 20100510 ) . Comparative material examined: C. amputatum Hedley, 1899 holotype AMS C68589 ( Fig. 3D ). Type locality: Cabbage Tree Bay , near Manly, in shell-sand, New South Wales ( Australia) .

Distribution: Inhaca Island, Mozambique.

Comparison:The new species is closely related to C. amputatum Hedley, 1899 ( Fig. 3D ), described from New South Wales, Australia. The greatest difference is in the septum, which in C. amputatum is “… well exerted, surrounded by a crown of the truncated tube, apex placed on the side of convex aperture” (Hedley 1899: 504). The position of the mucro (the “apex” in Hedley’s description) is dorsal in C. inhacaense and ventral in C. amputatum . Moreover, there is a wide geographical distance between the two type localities since no similar species have been found by the second author while studying WKH KXJH FROOHFWLRQV RI WKH 01+1 LQ WKH 7URSLFDO,QGR‒3DFL¿F.

The new species can be compared to the endemic Mediterranean species C. auriculatum Folin, 1868 due to the overall form of the tube. Neither has any sculpture but has a ringed aperture. However, the form of the septum is markedly different: it has WKH VKDSH RI D VPDOO, ÀDWWHQHG EDOO LQ inhacaense , while it is hemispheric with ear-like right-oriented mucro in auriculatum . Moreover, the distribution is greatly disjunct.

Figures

Fig. 3. (A–C) Caecum inhacaense VS. Q., KRORW\SH,,QKDFD,. (/RF. ƻƟ³ƽ), VFDOH EDU ƗƟƟ ȝP: ($) VKHOO;(%) septum; (C) detail of mucro; (D) Caecum amputatum Hedley, 1899, holotype AMS C68589, VFDOH EDU ƗƟƟ ȝP; (() Caecum inhacaense sp. n., paratype, juvenile, Inhaca I. (Loc. 2035), scale EDU ƗƟƟ ȝP.