Simulamerelina Ponder, 1985

Amati, Bruno, Giulio, Andrea Di & Oliverio, Marco, 2023, Shallow-water Rissoidae of the genera Alvania Risso 1826 Haurakia Iredale 1915 Parashiela Laseron 1956 Simulamerelina Ponder 1985 and Subestea Cotton 1944 Gastropoda Caenogastropoda Rissooidea from French Polynesia with the description of a new deep-water genus, Zoosystema 45 (25), pp. 803-892 : 853-854

Genus Simulamerelina Ponder, 1985

Simulamerelina Ponder, 1985: 49 .

TYPE SPECIES. — Merelina corruga Laseron, 1956: 436 , 479, fig. 136 by original designation.

DIAGNOSIS. — Shell of small to medium size for the family (height 1.1-3.5 mm); ovate-conic, slender, robust; axial and spiral sculpture present, spiral cordlets on the whole teleoconch, axial ribs not reaching the base, with rare exceptions; aperture subcircular, with thickened and duplicated peristome. Protoconch paucispiral with twisted nucleus, smooth spiral keels, the interstices studded with minute granules; the known species have a direct development. Colouration uniform white, and/or coloured teleoconch. Periostracum very thin. Head-foot: cephalic tentacles long, strap-like; pallial and metapodial tentacles present or absent; large, triangular anterior pedal gland; no posterior pedal gland. Operculum: oval, thin, nucleus eccentric, last whorl large (after Ponder 1985: 49).

REMARKS

Simulamerelina Ponder, 1985 was established as a subgenus of Manzonia Brusina, 1870 (see Ponder 1985: 49), then raised to genus rank by Faber & Moolenbeek (2004: 60) ( Criscione et al. 2016: 13; but see also Criscione & Ponder 2011: 82). Simulamerelina includes a group of twelve extant recognised species ( MolluscaBase 2023d), living from the lower intertidal to the continental shelf, where they are usually associated with algal facies, in the tropical Western Atlantic and the tropical Indo-West Pacific.

Although a revision of the genus is beyond the scope of the present work, we offer here some comments on taxa that show some morphological similarity to S. corrugata . Faber & Moolenbeek (1987) described Alvania (Simulamerelina) bermudensis Faber & Moolenbeek, 1987 , and Alvania (Flemellia) guesti Faber & Moolenbeek, 1987 from the Caribbean: they both show the same typical features of Simulamerelina .

Alvania ferruginea A. Adams, 1861 , described from Hakodadi Bay ( Japan), 12.8 m (= 7 fathoms) (A. Adams 1861: 138) [Image of syntypes (NMV no. F31420) at https://collections.museumsvictoria.com.au/specimens/620337 and (NHMUK no. 1874.5.18.7) https://www.europeana.eu/it/ item/11621/_NHMUK_ZOO_1874_5_19_7] not Alvania ferruginea sensu Golikov et al. (2001b: 158; identified Frigidoalvania sitta ( Yokoyama, 1926) , see Kantor & Sysoev [2006: 67, pl. 33, fig. B]) is, as suggested by Hasegawa (2014: 99) synonym of Simulamerelina tokyoensis ( Pilsbry, 1904) from Tokyo harbour ( Japan) ( Pilsbry 1904: 26, pl. 4, fig. 40).

Lozouet (1998) described three new species from the Upper Oligocene ( Alvania hortensis Lozouet, 1998 , Alvania boucheti Lozouet, 1998 , Alvania falsimerelina Lozouet, 1998 ), and one ( Alvania andraldensis Lozouet, 1998 ), from the Lower Miocene of Aquitaine ( France): the slender shells, peristome duplicate, microsculpture of spiral threads over the entire surface, protoconch with spiral sculpture with a predominant adapical cordlets are typical of Simulamerelina . If any of the first three is considered as a member of Simulamerelina , then the genus would be traceable back to the Oligocene of France. However, caution should be used in assigning fossil species to Simulamerelina . For instance, Fenella tokunagai Yokoyama, 1927 , was described from the Upper Musashino (probably Pleistocene) and Recent of Japan. Hasegawa (2000: 149, pl. 74, fig. 7) figured as “ Manzonia (Simulamerelina) tokunagai Yokoyama ” a species that might be distinct from the fossil described by Yokoyama (1927). While the fossil cannot be classified with security from the figure (and the types are lost, Oyama 1973: caption to plate 4), the Recent species figured by Hasegawa looks similar to a typical Simulamerelina : however, a live collected specimen from Japan, genetically assayed by Criscione et al. (2016) resulted more closely related to Onoba than to typical Simulamerelina .

Other species, clearly belonging to Simulamerelina , have been reported in literature from the Pacific. Brook & Marshall (in Brook 1998: 216) reported from the northern Kermadec Islands “ Manzonia (Simulamerelina) sp. aff. longinqua ( Rehder, 1980) ”, corresponding to Merelina pisinna sensu Oliver (1915: 519) ; they were possibly referring to “ Merelina pisinna ” sensu Powell (1927: 538 , pl. 27, fig. 11; not Alvania pisinna Melvill & Standen, 1896 ). Kay & Switzer (1974: 287, fig. 4D) reported “? Merelina sp. A ”, from Fanning Island, Pacific. Ponder (1985: 49) reported two unnamed species of Simulamerelina from Lifu, Loyalty Islands, Western Pacific. Mimoto & Nakao (2013: 52, pl.2, fig. 5) figured “ Merelina sp. † compared with M. tokyoensis Pilsbry ”, actually Simulamerelina . A typical Simulamerelina sp. from Île des Pins is illustrated at https:// ingokurtz.jimdofree.com/mollusca-weichtiere/rissoidae/.

The examination of c. 3900 specimens allowed us to identify six species of Simulamerelina in French Polynesia, all undescribed: Simulamerelina australes n. sp., Simulamerelina densestriata n. sp., Simulamerelina gracilis n. sp., Simulamerelina lepteseiras n. sp., Simulamerelina micrometrica n. sp., Simulamerelina tuamotu n. sp. Together with the new combinations herein, this brings the total of named species of Simulamerelina to 24, representing an increase of 100% (12 sp.) over the currently recognized diversity of the genus (see Table 7 ).