Palaina pomatiaeformis (Mousson, 1870)

Neubert, Eike & Bouchet, Philippe, 2015, The Diplommatinidae of Fiji - a hotspot of Pacific land snail biodiversity (Caenogastropoda, Cyclophoroidea), ZooKeys 487, pp. 1-85 : 39-40

Taxon classification Animalia Mesogastropoda Diplommatinidae

Palaina pomatiaeformis (Mousson, 1870) Figs 82-85

Diplommatina pomatiaeformis Mousson 1870, Journal de Conchyliologie, 18: 180, pl. VIII, fig. 2. Type locality: Vaini-Loba, in the southern part of Viti Levu.

Palaina (Macropalaina) pomatiaeformis , - Kobelt 1902, Cyclophoridae : 411.

Type material.

Possible syntypes ZMZ 526676/4. This lot contains 4 specimens from two places, as can be seen from the labels: 1. Viti Levu, "Vai Loban" [= Vaini-Loba], Graeffe [18]68 and 2. Viti Levu (S coast) Graeffe [18]72. The specimens from Vaini-Loba, the type locality, are mixed with those from the S coast, which reached Mousson after the description, and are not part of the type series. The Vaini-Loba material cannot be recognized; nonetheless, all specimens are conspecific. - Possible syntypes SMF 105141/2, Fiji, Viti Levu, coll. Möllendorff ex Mousson.

Material.

Viti Levu, surroundings of Qauia village, secondary wet forest, 20-50 m, -18.1001 178.3999, leg. Bouchet & Warén, 15.03.1999, MNHN/28, NMBE 516895/7; Viti Levu, surroundings of Laselevu village, 80 m, rainforest, -17.7532 178.1416, leg. Bouchet, Warén & Dayrat, 14.02.1999, MNHN/5.

Diagnosis.

Shell sinistral, large, elongate spire, light yellowish, widely spaced ribs with occasionally interspersed smaller ribs, central teleoconch whorls rapidly increasing in diameter suture deep, columella with a small knob-like denticle.

Description.

Shell sinistral, large, elongate spire, white to light yellowish; protoconch acute, granulated, consisting of 2 whorls; initial teleoconch whorls narrow, subsequent whorls rapidly increasing in diameter; last whorl not constricted, bulb of moderate size; teleoconch sculpture of widely spaced ribs with occasionally interspersed smaller ribs, rib pattern constant throughout the whole shell; deep suture and well-rounded whorls; last whorl ascending; aperture circular, in a central position, broadly adhered to the last whorl, peristomial rims connected; umbilicus closed, periomphalum narrow; internally, columella not reinforced with a small knob-like denticle at the base; bulb lamella very weak.

Operculum.

Outer surface with concentric rings of lamellae, internal surface concave and smooth inside, OD = 0.91.

Measurements.

Possible syntype (Fig. 82): H = 4.8; D = 2.26; PH = 1.53; PD = 1.57; W = 6.

Distribution

(Fig. 170). several localities on Viti Levu.

Remarks.

This is the type species of Macropalaina . The character states in this species compare very well with those in Palaina as defined here, the only difference being the remarkable lamellate operculum. Until the diagnostic value of the operculum has been investigated there is no reason to separate Macropalaina from Palaina , and they are here treated as synonyms, as did previous authors before us.

Palaina pomatiaeformis is the largest Palaina species so far known from Fiji. It differs from all other Palaina species by its narrow initial teleoconch whorls and the last whorls that rapidly increase in diameter. This characteristic " Cochlostoma -like" feature prompted Möllendorff to separate it in its own genus. However, an acute protoconch with somewhat narrower upper teleoconch whorls can also be found in Palaina godeffroyana and other species. Size and shell form make Palaina pomatiaeformis a species that cannot be confused with any other Palaina species.