Mautodontha (Mautodontha) harperae, 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 : 16

Mautodontha (Mautodontha) harperae sp. nov.

Figures 6 C; 9; 35E; 37C; 39.

Examined material (7 specimens). Holotype: MNHN 26529, Mk04. Paratypes: MNHN 26530, 6 shells, Mk04. Type locality. Moumu cave, Makatea (15.83347°S; 148.24933°W). Deposits inside cave. Limestone, alt. 30 m; station Mk04.

Diagnosis. Shell less than 4 mm in diameter, depressed, without flammulations; teleoconch sculptured by narrow, tall and relatively crowded primary axial ribs (> 120 ribs on body whorl); umbilicus V-shaped; palatal wall with 5 barriers, the first more prominent than the others, occasionally accompanied by 3 traces; parietal wall with 3 or occasionally 4 conspicuous barriers.

Description. Shell depressed, white, without flammulations. Shell wall thin, subpellucid; periostracum adherent, shiny. Apex flat to barely raised, spire elevated; later whorls descending more rapidly. Apical and umbilical sutures impressed; whorls and periphery rounded; basal and columellar walls transitioning smoothly. Transition between protoconch and teleoconch indistinct. Axial sculpture of the protoconch initially composed of pairs of fine riblets separated by interspaces 8–10 times the width of an individual riblet; riblets within each pair initially separated by a narrow interspace c. 1–2 times their width, subsequently coming closer and progressively merging into prominent ribs, which comprise the primary sculpture of the teleoconch. Single axial riblets between pairs occurring approximately from the second half of the first whorl, progressively increasing in number and transitioning into the secondary sculpture of the teleoconch. Spiral sculpture of the protoconch composed of approximately equidistant lirae with interspaces 2–4 times their width, persisting on the surface of the teleoconch, forming tiny nodules at intersections with the secondary axial sculpture. Teleoconch sculptured by narrow, tall axial ribs, with interspaces 4–5 times their width, overlaid by axial riblets with interspaces 2–4 times their width and by a spiral microsculpture of fine lirae. Umbilicus deep, V-shaped. Peristome crescent-shaped; columellar lip very slightly reflected. Palatal wall with 5 barriers and, occasionally, 3 traces; all palatal barriers extending c. 1/8 whorl, descending gradually anteriorly and posteriorly, approximately equidistant; barrier 1 columellar in position, not recessed within the aperture, more prominent than the others; barriers 2 to 4 basal in position, slightly recessed within the aperture, slightly more prominent than barrier 5; barrier 5 supraperipheral, deeply recessed. Palatal traces, when present, positioned between barriers 1 and 2, 2 and 3, 3 and 4, more deeply recessed and less prominent than barriers. Parietal wall with 3 or occasionally 4 conspicuous barriers, all extending beyond the line of vision from the peristome, descending abruptly anteriorly, not recessed within the aperture, approximately equidistant. Barriers 2 and 3 more prominent than barrier 1. Barrier 4, when present, less prominent than the others. Other shell features that can be expressed numerically are shown in Table 2 .

Remarks. The prominent parietal and columellar barriers of this species sets it apart from all other endodontids of Makatea. The only previously known species of Mautodontha with somewhat similar parietal and columellar barriers is M. (M.) ceuthma , from Raivavae, Austral Islands, which is easily distinguished from M. (M.) harperae by its supraperipheral groove and more spaced sculpture.

Etymology. This species is dedicated to Liz Harper, distinguished malacologist and palaeontologist.

Figures

FIGURE 6. Holotypes of: A. Mautodontha (Mautodontha) domaneschii sp. nov.; B. Mautodontha (Mautodontha) virginiae sp. nov.; C. Mautodontha (Mautodontha) harperae sp. nov. Scale bars = 2 mm.