Haurakia Iredale, 1915

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 : 833

Genus Haurakia Iredale, 1915

Haurakia Iredale, 1915: 449 .

Haurakiopsis Powell, 1937: 192 .

Vitricithna Laseron, 1956: 452 .

TYPE SPECIES. — Rissoia hamiltoni Suter, 1898: 2 , 3, 5; fig. IV (by original designation) accepted as Haurakia hamiltoni ( Suter, 1898) . Haurakiopsis : Haurakiopsis pellucida Powell, 1937 (by original designation) accepted as Haurakia pellucida ( Powell, 1937) . Vitricithna : Cithna marmorata Hedley, 1907 (by original designation) accepted as Haurakia marmorata ( Hedley, 1907) .

DIAGNOSIS. — Shell ovate-conical, with weak or moderately strong axial or smooth ribs; in some species the ribs are interrupted at the periphery due to the presence of a spiral cordlets. Anterior edge of the aperture with shallow, wide excavation, posterior sinus wide, distinct. Protoconch apparently smooth or with one or more spiral threads or rows of minute granules; about 1.5 whorls with large nucleus (when paucispiral) or small nucleus and about 2.5 whorls (when multispiral). Colouration of teleoconch variable with several patterns. Head-foot: long ciliated cephalic tentacles; foot constricted in middle, with posterior mucous gland; anterior and posterior pallial tentacles; a single, slender metapodial tentacle (see Ponder 1985: 29; Kay 1979). Operculum simple, thin, nucleus eccentric, last whorl large ( Ponder 1985: 131, fig. 82C).

REMARKS

Previously considered as a subgenus of Pusillina Monterosato, 1884 ( Ponder 1985: 29), it is now ranked as a full genus ( Criscione et al. 2016). Rissoia hamiltoni (type species of Haurakia ) and Cithna marmorata (type species of Vitricithna ) share some general teleoconch, head-foot, radular and anatomical features (including male and female genital ones), and their closer affinity with respect to a distinct clade of Pusillina species is supported by molecular data ( Criscione et al. 2016). However, Criscione et al. (2016: 14) also treated Haurakia and Vitricithna as distinct genera, scoring a large genetic divergence between the two type species (larger than that scored between widely recognised genera); the issue should be assessed by a denser sampling in a molecular phylogenetic framework. We keep here Cithna marmorata in the genus Haurakia following current treatment [ Ponder 1985: 29-30, fig. 82A-E; Hasegawa 2000: 149, pl. 74, fig. Rissoidae-1; both as Pusillina (Haurakia) ]. Haurakia , as currently conceived, includes c. 35 species, of which seven fossil, and dates back to the Miocene-Pleistocene of New Zealand and the Oligocene-Miocene of Tasmania ( Ponder 1985: 30).