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FRAUSSEN, K. & ROSADO, J., 2013. A new Zemiropsis Thiele, 1929 (: Babyloniidae) from southeastern Africa...

Article · October 2013

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Gloria Maris 52 (6) 178 - 183 Antwerp; 13 October 2013

A new Zemiropsis Thiele, 1929 (Gastropoda: Babyloniidae) from southeastern Africa

Koen FRAUSSEN (1) & José ROSADO (2)

(1) Leuvensestraat 25, B-3200 Aarschot, Belgium [email protected] (2) Av. Friedrich Engels, n. 373, 1e, Maputo, Moçambique [email protected]

Keywords: , GASTROPODA, BABYLONIIDAE, Zemiropsis, South Africa, Mozambique, new taxon.

Abstract: Zemiropsis demertziae sp. nov. is described from Natal (South Africa) and southern Mozambique. Conchological differences in suture and shape distinguish this new species from Zemiropsis pulchrelineata (Kilburn, 1973).

Introduction: The southern part of East Africa is home to a unique molluscan fauna: partly connected to the South African fauna, partly connected to the East African fauna and with fragments from the nearby abyssal bassins. Many studies on the South African molluscan fauna included the coast of Natal. The Mozambican fauna, ignored in the past, has been the subject of intensive collecting for some decades, but still many discoveries are made nowadays. The second author of the present paper has participated in recent expeditions in the Mozambique Channel and has spent lots of time and much energy collecting shells along the Mozambican coast. Nevertheless, the species described in the present paper is represented by a single Mozambican specimen only. The other three specimens are from South Africa and were collected more than 25 years ago. We hereby add Zemiropsis demertziae sp. nov. to the southeastern African fauna.

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SYSTEMATICS: Family: BABYLONIIDAE Kuroda, Habe & Oyama, 1971 Genus: Zemiropsis Thiele, 1929 Zemiropsis Thiele, 1929: 332 (gen. nov. pro , Olividae). Type species: Eburna papillaris G. B. Sowerby I, 1825, by original designation.

Remarks: The genus Zemiropsis is restricted to a limited geographical area: from southeastern South Africa to Mozambique.

The genus Zemiropsis was briefly discussed by Marais & Kilburn (2010: 295-298), who figured all species for the first time. For an extensive discussion of the genus, together with all other members of Babyloniidae, we refer to Fraussen & Stratmann (2013: 72-77).

Zemiropsis demertziae sp. nov. Figs 1-6

2013: species aff. Pulchrelineata - Fraussen & Stratmann, 77, text fig. 53.

Type material: Holotype: 29.0 mm, South Africa, Natal, by fishermen, in deep water, leg. L. van der Westhuizen, 1987, ex. coll. Dawn Brink, in KwaZulu-Natal Museum, Pietermaritzburg, South Africa, NMSA W9478/T3156. Paratype 1: 36.1 mm, same locality, collection Maria Demertzis, Greece; paratype 2: about 23.5 mm (attached to Xenophora), South Africa, off Durban, trawled, 400 m deep, 4/2009, collection Koen Fraussen, Belgium, KF-5762; paratype 3: 18.8 mm, off southern Mozambique, NE of Ponya do Ouro, 26°43.50’S, 33°00.40’ E, 180-200 m deep, ex-pisce, collection José Rosado, Mozambique.

Type locality: South Africa, Natal, by fishermen, in deep water, 1987.

Material studied: Aside from the type material listed above, we studied several fragments trawled off southern Mozambique, NE of Ponta Techobanine, 26°40.20’S, 33°00.10’ E, 180-200 m deep (collection José Rosado).

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Range and habitat: Only known from the type material listed above. Habitat unknown. It is most probable that the species lives among larger rocks, as such places are avoided by trawlers because of the potential damage to the nets. Hard sediment inside the whorls and attached to the outer surface of the holotype indicate that this shell originates from young holocene deposits. Z. pulchrelineata and Z. rosadoi (Bozzetti, 1998) are also known from such layers.

Description: Shell of medium size (up to 36.1 mm), thick, solid. Shape broadly fusiform with moderately high spire. Protoconch blunt, paucispiral, consisting of 1 smooth whorl, diameter 1.7 mm. Transition to teleoconch indistinct, marked by a fine, obscure incremental line. Colour white (holotype), most probably because faded; paratype 3 (collected alive) with brown protoconch. Teleoconch with 4 smooth, glossy whorls (paratype 1 with 4 ½ whorls), spire whorls moderately convex, body whorl laterally slightly flattened. Suture distinct; first ½ whorl with a narrow, deep sutural fissure; growing broader, forming a deep canal, outer margin with a weak ridge that accentuates shoulder and tabulate shape. Surface of all whorls smooth, glossy; covered with numerous obscure incremental lines; apex with fine, extremely obscure spiral cords only visible under microscope. Aperture typical of genus: semi-oval, wide, adapical border slightly flattened, adapical part towards suture weakly pinched. Outer lip thick, smooth (edge broken in holotype). Columella concave, gently curved, smooth; callus thick, glossy, edge rather thin at outer margin, but projecting along base. Umbilicus moderately wide-open, deep, separated from siphonal fasciole by a moderately sharp fold, edge rather glossy. Siphonal fasciole broad, weakly concave, white (in paratype 1 patterned with some brown dots), separated from body whorl by a sharp edge curling up along the surface of the body whorl. Siphonal canal open, broad, short. Aperture higher than 1/2 of total shell length.

Colour off-white to cream; paratype 3 (collected alive) rather yellowish with brown apex. First and second whorl without pattern. Third whorl starting with 6 fine, yellow (holotype) to reddish brown (paratype 3) spiral lines, weakly diagonally orientated. After about ¼ whorl, a new spiral line appears at the shoulder of the third whorl, starting its path moving downwards along the whorl. This number increases: body whorl with about 9 such starting spiral lines. Paratype 3 with a more irregular pattern with a few spiral lines fusing together and some spiral lines appearing in interspaces. Penultimate whorl with 6 or 7 spiral lines. Body whorl with about 20 spiral lines.

Operculum (paratype 3) thin, semi-transparent, yellowish brown, claw-shaped with laterally flattened sides and sharp, terminal nucleus.

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Comparison: Zemiropsis demertziae sp. nov. is characterised by the broad shape, the broad sutural canal, the moderately wide umbilicus and the weakly concave siphonal fasciole in combination with the delicate pattern of fine spiral lines.

Zemiropsis pulchrelineata (Kilburn, 1973) differs by the slenderer shape, the narrow sutural canal, the convex surface of the siphonal fasciole, the narrower umbilicus and the rather thick outer edge of the columellar callus.

The shape and size of the subsutural canal seem to be specific in most Babyloniidae. However, some variation is observed in some species. One case is the broadness of the subsutural canal, which slightly varies in and B. valentiana, causing some confusion (see Fraussen & Stratmann, 2013: 32, 62-66, 70). The second case is the presence or absence of subsutural canaliculation on the older (lower) whorls in B. areolata (see Fraussen & Stratmann, 2013: 46-48). In both cases the variation is recognisable along widely separated geographical areas, forming a cline. Zemiropsis demertziae sp. nov. was until now considered as a variety of Z. pulchrelineata, but both morphotypes are collected together in Natal and Mozambique, being topotypic, and therefore cannot be considered as forms (ecophenotypes) or subspecies.

Etymology: Zemiropsis demertziae sp. nov. is named to honour Maria Demertzis, our good friend from Greece, for her major conchological contribution by collecting and distributing shells and her feeling for the aesthetic aspect and the visual beauty of shells.

References: Bozzetti, L., 1998. Descrizione di una nuova specie di Babylonia Schluter, 1838 dal Canale di Mozambico ed una nuova specie di Siliquaria Bruguière, 1792 dalle Filippine [Description of a new species of Babylonia Schlüter, 1838 from the Mozambique Channel and a new species of Siliquaria Bruguière, 1792 from the Philippines]. Malacologia Mostra Mondiale 27: 27-31. Fraussen, K. & Stratmann, D., 2013. The Family Babyloniidae. In: Poppe, G. T. & Groh, K., (ed.) A conchological iconography. ConchBooks, Harxheim. Kilburn, R. N., 1973. Notes on some benthic Mollusca from Natal and Moçambique, with descriptions of new species and subspecies of Calliostoma, Solariella, Latiaxis, Babylonia, Fusinus, Bathytoma and Conus. Annals Natal Mus. 21 (3): 557-578, figs. 1-17. Kuroda, T., Habe, T. & Oyama, K., 1971. The Sea Shells of Sagami Bay, collected by His Majesty the Emperor of Japan. Maruzen, Tokyo. Marais, J. P. & Kilburn, R. N., 2010. Babyloniidae. In: Marais, A. P. & Seccombe, A. D. (ed.) Identification Guide to the Seashells of South Africa. Centre for Molluscan Studies. Thiele, J., 1929. Handbuch der systematischen Weichtierkunde. Vol. 1, part 1. Jena.

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Plate:

1-13: Zemiropsis demertziae sp. nov. 1-4: Holotype, 29.0 mm, South Africa, Natal, by fishermen, in deep water, in KwaZulu-Natal Museum, Pietermaritzburg, South Africa, NMSA W9478/T3156. 5-9: Paratype 1, 36.1 mm, same locality, collection Maria Demertzis, Greece. 10-11: Paratype 2, about 23.5 mm, South Africa, off Durban, trawled, 400 m deep, collection Koen Fraussen, Belgium, KF-5762. 12-13: Paratype 3, 18.8 mm, southern Mozambique, NE of Ponya do Ouro, 26°43.50’S, 33°00.40’ E, 180-200 m deep, ex-pisce, collection José Rosado, Mozambique.

14-20: Zemiropsis pulchrelineata (Kilburn, 1978) 14-15: 26.1 mm, South Africa, Natal, 25 km SE off Durban, by fishermen, in deep water, in collection Koen Fraussen, Belgium, KF-6714. 16-20: 30.6 mm, South Africa, Natal, by fishermen, in deep water, in collection Koen Fraussen, Belgium, KF-4487.

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