Diancta martensi (H. Adams, 1866) H. Adams, 1866

Neubert, Eike & Bouchet, Philippe, 2015, The Diplommatinidae of Fiji - a hotspot of Pacific land snail biodiversity (Caenogastropoda, Cyclophoroidea), ZooKeys 487, pp. 1-85 : 7

Taxon classification Animalia Mesogastropoda Diplommatinidae

Diancta martensi (H. Adams, 1866) comb. n. Figs 5-10

Diplommatina (Diancta) martensi H. Adams 1866, Proceedings of the Zoological Society of London, 1866: 446, t. 38 f. 11. Type locality: unknown.

Diplommatina distorta "Mousson, 1869" 1869, Schmeltz, Museum Godeffroy Catalog IV: 75 [nomen nudum].

Palaina (Palaina) martensi , - Kobelt 1902, Cyclophoridae : 400.

Palaina distorta , - Solem 1959, Fieldiana Zoology, 43: 191 [Fiji, Tonga; nomen nudum].

Palaina martensi , - Solem 1959, Fieldiana Zoology, 43: 191 [Fiji, Tonga].

Diplommatina distorta , - Bieler & Petit 2012, Zootaxa 3511: 45 [nomen nudum].

Type data.

Possible syntype NHMUK 1867.3.22.4 [said to be from Australia, Lord Howe (error)].

Material.

Fiji, Viti Levu, mouth of cave near Suva Bay, coll. Bryant Walker ex Ponsonby, UMMZ 88697 ( Solem 1959 as Palaina distorta ); Viti Levu, surroundings of Qauia village, secondary wet forest, 20-50 m, -18.0999 178.3999, leg. Bouchet & Warén, 15.03.1999, MNHN/394, NMBE 516879/25; Viti Levu, surroundings of Laselevu village, 80 m, rainforest, -17.7532 178.1416, leg. Bouchet, Warén & Dayrat, 14.02.1999, MNHN/92, NMBE 516880/10. - Tonga, Tongatabu, coll. Bryant Walker ex Ponsonby, UMMZ 87919.

Diagnosis.

Shell medium sized, sinistral, last whorl strongly constricted, last whorl strongly ascending, apertural rims connected by a large polished callus, axial palatalis.

Description.

Shell medium sized, sinistral, elongate oval, yellowish to whitish; last whorl strongly constricted; protoconch large, 1-1.5 whorls, bulbous obtuse, pitted; umbilicus closed, periomphalum narrow; teleoconch sculpture of widely spaced ribs on the initial and the central whorls, ribs becoming coarser and more widespread on the last third of the last whorl; last whorl strongly ascending; aperture quadrate, peristome connected to the last whorl; apertural rims connected by a large polished callus; aperture with a slightly enlarged process over the left edge; no pleats visible in the aperture; inside the shell, columellar plate split into two plates of equal size, with a small but strong axial palatal fold opposite.

Operculum corneous, flat, internally with a small lamella.

Measurements.

Possible syntype (Fig. 5): H = 3.2; D = 2.57; PH = 1.51; PD = 1.48; W = 5.

Distribution

(Fig. 170). Recorded from Fiji, Viti Levu, and Tonga, Tongatabu by Solem (1959: 191).

Remarks.

The possible syntype matches well the figure of Adams (pl. 38, fig. 11). The museum’s label records Lord Howe Island as origin, but there is no locality given in the original description. However, the possible syntype does not match the illustrations of Stanisic et al. (2010) of the Lord Howe Island species of Diancta . Thus, the NHMUK label is incorrect, the provenance of Diancta martensi remains unknown, and the status of NHMUK 1867.3.22.4 is doubtful (possible syntype). On the other hand, the specimens illustrated here from Fiji and Tonga (Figs 6-10) are almost identical with the possible syntype, which thus might originate from one or other of these island groups.

In their analysis of the Godeffroy sales catalogue, Bieler and Petit (2012: 45) listed " Diplommatina distorta Mousson" as a nomen nudum. To complete the history of this name, the Mousson collection in Zurich has been checked: the lots ZMZ 526698/7 (" Diplommatina martensi H. Adams, Diplommatina distorta Mss, Viti Levu, Graeff. 68" in Mousson’s handwriting), and ZMZ 526699/2 (" Diplommatina distorta . Mss, Viti Levu, Graeffe 68" in Mousson’s handwriting) were examined. It is clear that Mousson intended to separate these specimens under the name " distorta ", but this remained a manuscript name. In fact, both lots contain typical specimens of Diplommatina martensi . It is not clear why Solem used " Diplommatina distorta Mousson", nor why he considered the two taxa as distinct.

We here identify the modern lots recorded above with this species. Although on average, specimens from these lots are somewhat smaller than the possible syntype, no other character justifies their separation.