Ledella marisnostri La Perna 2004, n. sp.

• Main Author: La Perna, R.
• Format: Text
• Language: unknown
• Published: Zenodo 2004
• Subjects: Biodiversity; Taxonomy; Animalia; Mollusca; Bivalvia; Nuculanoida; Nuculanidae; Ledella; Ledella marisnostri; Hannah; Salas; North Atlantic
• Online Access: https://dx.doi.org/10.5281/zenodo.4653811; https://zenodo.org/record/4653811

Ledella marisnostri n. sp. (figure 4 a–e) Type material. Holotype (right valve, MZB 40663) and five paratypes (loose valves, author's collection). Type locality. Cruise ' Interreg Italia-Albania', southern Adriatic, st. 55, 40 ° 00 ∞ 59 ◊ N, 19 ° 08 ∞ 55 ◊ E, 976 m. Material examined. Only the type material. Description. Shell small, ovate, moderately convex and elongated, inequilateral, thin-walled. Umbo rather large, weakly projecting from shell outline. Antero-dorsal margin sloping, slightly convex, smoothly curving into a well-rounded anterior margin. Postero-dorsal margin sloping, longer than antero-dorsal one, slightly convex, curving into a moderately developed blunt rostrum at shell height midline. Ventral margin wide, strongly convex, evenly rounded except for an obscure posterior sinuosity marking out rostrum. Hinge plate moderately thick, making a 130 ° angle, with rows of similar length. Dentition taxodont, with chevron-shaped teeth, numbering seven anteriorly and six posteriorly in holotype. Ligamental pit rather deep, somewhat triangular. Muscle scars and pallial line indistinct. Surface with fine growth striae, some of them more incised. Periostracum thin, shiny, yellowish. Prodissoconch elliptic, ca 250 µ m long. Holotype 2.08 mm in length, 1.53 mm in height, 0.50 in breadth. Paratypes 1.65–2.27 mm in length. Etymology. After Mare nostrum , Latin name for the Mediterranean Sea. Distribution. Only known from the type locality. Remarks. The sole species of Ledella so far known from the Mediterranean is L. messanensis , with a wide latitudinal distribution through the European Atlantic (Warén, 1978, 1989; Allen and Hannah, 1989; Salas, 1996). However, it differs markedly from the present species by being bigger (up to ca 5 mm), much more solid, and with a longer and sharper rostrum. Also, the juveniles of L. messanensis are somewhat pointed posteriorly and thick-shelled. A North Atlantic species, Ledella confinis (Smith, 1885), revised by Warén (1978), may be somewhat reminiscent of L. marisnostri n. sp., but it is larger, more solid, with a more pointed rostrum and with a strongly oblique umbo. The present species seems close to the L. messanensis group, although it is not particularly similar to any of the European species. : Published as part of La Perna, R., 2004, The identity of Yoldia micrometrica Seguenza, 1877 and three new deep-sea protobranchs from the Mediterranean (Bivalvia), pp. 1045-1057 in Journal of Natural History 38 on pages 1052-1053 : {"references": ["WAREN, A., 1978, The taxonomy of some North Atlantic species referred to Ledella and Yoldiella (Bivalvia), Sarsia, 63, 213 - 119.", "WAREN, A., 1989, Taxonomic comments on some protobranch bivalves from the Northeastern Atlantic, Sarsia, 74, 223 - 259.", "ALLEN, J. A. and HANNAH, F., 1989, Studies on the deep-sea Protobranchia: the Subfamily Ledellinae (Nuculanidae), Bulletin of the Natural History Museum, Zoology Series, 55, 123 - 171.", "SALAS, C., 1996, Marine bivalves from off the Southern Iberian Peninsula collected by the Balgim and Fauna 1 expeditions, Haliotis, 25, 33 - 100."]}