Pseudolibera paraminderae, Sartori, André F., Gargominy, Olivier & Fontaine, Benoît, 2014

Sartori, André F., Gargominy, Olivier & Fontaine, Benoît, 2014, Radiation and decline of endodontid land snails in Makatea, French Polynesia, Zootaxa 3772 (1), pp. 1-68 : 50-54

Pseudolibera paraminderae sp. nov.

Figures 30 B; 32; 36C; 38C; 39.

Examined material (123 specimens). Holotype: MNHN 25677, Mk04. Paratypes: MNHN 25678, 8 shells, Mk04. Additional material: 61 shells, Mk04; 19 shells, Mk09; 34 shells, Mk10.

Type locality. Moumu cave, Makatea (15.83347°S; 148.24933°W). Deposits inside cave. Limestone, alt. 30 m; station Mk04.

Diagnosis. Shell less than 6 mm in diameter, depressed, flammulated; apex and spire elevated; peripheral keel upturned from the fifth whorl onwards; teleoconch with crowded axial ribs (> 150 ribs on body whorl) and spiral riblets, the latter present only on the shell base; palatal wall devoid of barriers; 1 parietal barrier extending 1/2 whorl, not bifurcated.

Description. Shell depressed, dome-shaped, white to light fawn, with regularly spaced, amber flammulations on the apical surface, absent on the shell base; flammulations fading out on the sixth whorl. Shell wall thin, opaque to subpellucid; periostracum adherent, shiny. Apex and spire elevated; later whorls descending slightly more rapidly. Apical suture adpressed at apex, progressively deepening in subsequent whorls; umbilical suture adpressed. Initial 4 whorls gently concave above peripheral keel, transitioning from the fifth whorl onwards into sharply concave, with an upturned peripheral keel and conspicuous supraperipheral groove. Whorls broadly convex in the vicinity of the apical suture and on shell base; gently concave below the peripheral keel; junction of basal and columellar walls initially obtusely angled, developing a keel approximately from the fifth whorl onwards. Transition between protoconch and teleoconch indistinct. Primary axial sculpture of the protoconch composed of relatively broad ribs, with interspaces c. 2–3 times their width; 2–4 secondary axial riblets, each c. 1/5 the width of the primary ribs and wavy in morphology, occupying the interspaces between primary ribs. Primary ribs of the protoconch gradually transitioning into narrower ribs, slightly taller peripherally than above and below peripheral keel, and comprising the primary axial sculpture of the teleoconch; secondary riblets of the protoconch gradually increasing in number and persisting as the secondary axial sculpture of the teleoconch. Axial sculpture not reduced on shell base. Spiral sculpture present only on the shell base, restricted to the vicinity of the umbilicus or frequently extending almost to the peripheral keel, composed of riblets with interspaces c. 1–2 times their width; spiral riblets forming nodular projections at intersections with axial ribs and riblets. Umbilicus rapidly expanding in diameter for approximately the first 3 whorls, remaining constant in diameter for approximately 1 whorl, subsequently constricted by inward growth of the lower columellar wall and lip. Peristome subquadrate; columellar lip reflected. Palatal wall devoid of barriers. Parietal wall with 1 barrier, positioned slightly closer to the apical than the umbilical suture, descending gradually anteriorly and posteriorly, extending for c. 1/2 whorl. Other shell features that can be expressed numerically are shown in Table 3.

Remarks. A marked change in the concavity of the supraperipheral wall, with the peripheral keel upturned from the fifth whorl onwards, is a unique feature of P. paraminderae , and the easiest criterion for recognizing fullygrown specimens. Specimens displaying fewer than five whorls are very similar to P. lillianae in general shell shape, but are easily distinguished from that species by their lack of spiral sculpture on the apical surface, as well as by their smaller shell size.

Etymology. This species is dedicated to Paraminder Dhillon, wife of the first author.

Figures

FIGURE 30. Holotypes of: A. Pseudolibera extincta sp. nov.; B. P. paraminderae sp. nov.; C. P. elieporoii sp. nov.; D. P. parva sp. nov. Scale bars: A – C = 5 mm; D = 3 mm.