Georissa hungerfordi Godwin-Austen, 1889

Zacaery Khalik, Mohd, P. Hendriks, Kasper, J. Vermeulen, Jaap & Menno Schilthuizen,, 2019, Conchological and molecular analysis of the " non-scaly " Bornean Georissa with descriptions of three new species (Gastropoda, Neritimorpha, Hydrocenidae), ZooKeys 840, pp. 35-86 : 53-54

Georissa hungerfordi Godwin-Austen, 1889 Figures 1D, 11 A–K

Georissa hungerfordi Godwin-Austen, 1889: 354, Plate XXXIX, fig. 9.

Georissa lowi Smith, 1893: 351.

Georissa williamsi Godwin-Austen: Thompson and Dance 1983: 124 (non G. williamsi Godwin-Austen, 1889; G. javana Möllendorff, 1897; G. javana intermedia Möllendorff, 1897).

Type locality.

Borneo.

Type material.

Lectotype (Designation by Thompson and Dance 1983). Borneo: NHMUK 1891.3.17.864 (glued on paper) (Fig. 1D).

Other material.

Rumbang, Sarawak: NHMUK 1893.6.7.71, NHMUK 1893.6.7.108-110, NHMUK 94.7.21.58 (glued on paper), NHMUK 94.7.20.63-4 (glued on paper). Regu, Kampung Timurang, Padawan/Penrissen, Kuching, Sarawak (01°12.82'N, 110°16.82'E): MZU/MOL 16.10. Gunong Mawah, Kampung Bengoh, Padawan/Penrissan, Kuching, Sarawak (01°16.15'N, 110°15.46'E): MZU/MOL 16.11 (Fig. 11). Gunong Seduai/Duai, Kampung Timurang, Padawan/Penrissen, Kuching, Sarawak (01°12.25'N, 110°17.00'E): MZU/MOL 16.12. Gunong Sirat, Kampung Timurang, Padawan/Penrissen, Kuching, Sarawak (01°12.42'N, 110°16.52'E): MZU/MOL 16.13. Gunung Bra’ang, upper Penrissen valley, Kuching, Sarawak (01°14.12'N, 110°16.21'E): JJV 12451. Gunung Babu, upper Penrissen valley, Kuching, Sarawak (01°12.15'N, 110°16.18'E): JJV 12542. 12 km NNE of Padawan village, upper Penrissen valley, Kuching, Sarawak: JJV 13067, JJV 13070. Upper Penrissen valley, Bt. Krian, Kuching, Sarawak (01°12.20'N, 110°21.54'E): JJV 14222. Gunung Manok, upper Penrissen valley, Kuching, Sarawak (01°11.56'N, 110°16.16'E): JJV 14224. Gunung Kayan, upper Penrissen valley, Kuching, Sarawak (01°15.45'N, 110°15.30'E): JJV 14225. Sungei Bukar headwaters, G. Buros S of Gunung Nambi, Kuching, Sarawak (01°09.55'N, 110°27.59'E): JJV 14223. Gunung Pangga, Bau, Sarawak: JJV 2165. Gunung Jambusan, Bau, Sarawak: JJV 2213. Gunung Kapor, Bau, Sarawak: JJV 2274.

Description.

Protoconch. Colour: orange. Sculpture pattern: smooth. Teleoconch. Colour: orange. First whorl: convex. Subsequent whorls: convex, shell shape slender to broad. Suture: well-impressed suture, straight to slightly concave, and narrow shoulder. Number of whorls: 2 ½– 3 ¼. SH: 1.35-1.85 mm. SW: 1.38-1.20 mm. SI: 1.16-1.36. Shell sculpture. Radial sculpture: absent, only weak to strong growth lines present throughout the shell surface. Spiral sculpture: present, strong spiral ribs, regularly spaced, with ca. 7-10 spiral ribs on the body whorl of the adult individual, appearing immediately after the protoconch, sometimes distorted/discontinuous by growth lines, more densely spaced spiral cords at the basal part of the body whorl. Aperture. Shape: rounded to slightly ovoid, straight to concave parietal side, palatal edge contiguous with the body whorl, basal side convex. AH: 0.63- 0.79 mm. AW: 0.67-0.83 mm. AI: 0.89-1.06.

Diagnosis.

Georissa hungerfordi is characterised by the strong spiral sculpture with ca. 7-10 spiral ribs on the body whorl. The shell shape approaches the shape of G. trusmadi and G. pachysoma . Georissa hungerfordi has stronger spiral sculpture compared to G. pachysoma but weaker compared with G. trusmadi . The spiral ribbings resemble G. insulae , which has, however, a more elongated and slender shell shape.

Distribution.

Georissa hungerfordi is distributed from Bau to Padawan/Penrissen, Kuching, Sarawak.

Discussion.

Thompson and Dance (1983) considered G. hungerfordi a junior synonym of G. williamsi . We are, however, of the opinion that G. hungerfordi is a valid species based on the distinctly raised spiral sculpture of the shell compared to G. williamsi . Georissa lowi (Smith, 1893) is a junior synonym of G. hungerfordi . See also discussion in G. williamsi Godwin-Austen, 1889.

Molecular analysis.

ML and Bayesian analyses show that the samples of G. hungerfordi (16S: n = 14; CO1: n = 11) form a monophyletic group with 100% BS and 100% PP, sister group to the “scaly” group, except G. saulae .