Mautodontha (Mautodontha) domaneschii, 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 : 13-14

Mautodontha (Mautodontha) domaneschii sp. nov.

Figures 6 A; 7; 35B; 37B; 39.

Examined material (744 specimens). Holotype: MNHN 25585, Mk04. Paratypes: MNHN 25586, 8 shells, Mk04. Additional material: 438 shells, Mk04; 11 shells, Mk07; 99 shells, Mk08; 187 shells, Mk09.

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

Diagnosis. Shell less than 3.5 mm in diameter, discoidal, with a shallow supraperipheral groove, without flammulations; teleoconch sculptured by broad, relatively well-spaced primary axial ribs (<90 ribs on body whorl); umbilicus V-shaped; peristome subovate; palatal wall with 4 or rarely 5 barriers; parietal wall with 3 or rarely 4 barriers.

Description. Shell discoidal, white to fawn, without flammulations. Shell wall thin, subpellucid to opaque; periostracum adherent, shiny. Apex and spire barely elevated; last whorl descending more rapidly. Apical and umbilical sutures impressed; periphery weakly angled. Whorls flattened above periphery, with a very shallow supraperipheral groove developing approximately from the middle of the fourth whorl onwards; whorls evenly rounded on basal margin. Transition between protoconch and teleoconch indistinct. Axial sculpture of the protoconch initially composed of pairs of riblets separated by interspaces 8–12 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 5–10 times their width, persisting on the surface of the teleoconch, forming tiny nodules at intersections with the secondary axial sculpture. Teleoconch sculptured by broad axial ribs, with interspaces 2–3 times their width, slightly taller at periphery than elsewhere, overlaid by wavy axial riblets with interspaces c. 1–2 times their width and by a spiral microsculpture of fine lirae. Umbilicus shallow, V-shaped. Peristome subovate. Palatal barriers usually 4, rarely 5, extending c. 1/8 whorl, descending gradually anteriorly and abruptly posteriorly, regularly spaced, slightly recessed; barrier 1 at the junction of basal and columellar walls; barriers 2 and 3 basal, barrier 5 supraperipheral; barrier 4, when present, positioned approximately midway between barriers 3 and 5; barriers 1, 4 and 5 slightly to markedly less prominent than barriers 2 and 3. Parietal barriers usually 3, rarely 4, extending c. 3/16 whorl, descending gradually anteriorly and abruptly posteriorly, not recessed, taller along the posterior third; barriers 1 and 2 more prominent than barrier 3, or barrier 1 more prominent than barriers 2, 3 and 4. Other shell features that can be expressed numerically are shown in Table 2 .

Remarks. The combination of a wide, V-shaped umbilicus with a shallow supraperipheral groove immediately separates M. (M.) domaneschii from all other endodontids of Makatea. M. (M.) ceuthma ( Solem, 1976) , from Raivavae, Austral Islands, is the only previously known species of the genus with a supraperipheral groove, but that species is quite distinct from M. (M.) domaneschii , exhibiting a relatively higher shell and more numerous and prominent apertural barriers.

Etymology. This species is dedicated to the late Osmar Domaneschi, malacologist and fabulous teacher.

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.