Pseudolibera parva, 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 : 55-58

Pseudolibera parva sp. nov.

Figures 30 D; 34; 36B; 37C; 39.

Examined material (44 specimens). Holotype: MNHN 25679, Mk03. Paratypes: MNHN 25680, 8 shells, Mk03. Additional material: 20 shells, Mk03; 4 shells, Mk10; 11 shells, Mk12.

Type locality. Road to Moumu, descending between cliffs, Makatea (15.83496°S; 148.24928°W). Foot of the cliff. Limestone, alt. 50 m; station Mk03.

Diagnosis. Shell less than 5 mm in diameter, depressed, flammulated; apex flat to slightly raised, spire elevated; peripheral keel poorly marked; teleoconch sculptured by relatively well-spaced axial ribs (<100 ribs on body whorl) and by spiral ribs, the former taller than the latter and reduced in height in the vicinity of the umbilicus; palatal wall devoid of barriers; 1 parietal barrier extending 3/4 whorl, not bifurcated.

Description. Shell depressed, white, with regularly spaced, amber to maroon flammulations, quickly fading out on shell base; first two to three whorls often with a fawn background coloration, in addition to the flammulations. Shell wall thin, opaque to subpellucid; periostracum adherent, shiny. Apex flat to slightly raised; spire elevated; later whorls descending more rapidly. Apical suture impressed; umbilical suture adpressed. Whorls very gently concave above and straight below poorly marked peripheral keel, gradually transitioning into sharply convex toward the apical suture and gently convex toward the shell base; junction of basal and columellar walls initially obtusely angled, developing a keel approximately from the fourth whorl onwards. Transition between protoconch and teleoconch indistinct. Protoconch sculptured by primary axial ribs, with interspaces approximately twice their width, overlaid by a fine secondary sculpture of oblique, axial and spiral elements; oblique elements represented by irregular riblets on the first 1/2 whorl, gradually transitioning into axial riblets with interspaces c. 1–2 times their width; spiral sculpture of the protoconch composed of fine lirae, with interspaces 2–4 times their width, forming tiny nodules at intersections with oblique and axial riblets. Primary ribs of the protoconch gradually transitioning into taller ribs, which comprise the primary axial sculpture of the teleoconch; secondary axial riblets of the protoconch gradually increasing in number and persisting as the secondary axial sculpture of the teleoconch. Spiral lirae fading out on second whorl, replaced from the third whorl onwards by the spiral sculpture of the teleoconch. Spiral ribs of the teleoconch separated by interspaces 3–5 times their width, forming nodules at intersections with axial ribs and riblets. Primary axial ribs of the teleoconch reduced in height near the umbilicus. Umbilicus rapidly expanding in diameter for approximately the first 3 whorls, 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. 3/4 whorl. Other shell features that can be expressed numerically are shown in Table 3.

Remarks. P. parva is the smallest known species of Pseudolibera . Specimens collected at station Mk12 have the shell more tightly coiled, with somewhat shallower sutures ( Fig. 34 D), but in all other respects are identical to material from the type locality and vicinity.

Etymology. From parvus (Latin), meaning small, pertaining to the size of the shell of this species.

of measurements. Abbreviations: ah, aperture height; aw, aperture width; d, shell diameter; h, shell height; rn, number of

ribs on body whorl; sp, spire protrusion; u, diameter of umbilicus; wn, number of whorls.

Specimen d wn rn h ah aw sp u h/d ah/aw u/d sp/h

P. lillianae

holotype 6.40 5.25? 3.10 1.52 2.70 0.82 1.14 0.48 0.56 0.18 0.27 specimen 1 8.08 6.31 146 4.05 1.71 3.05 1.49 1.68 0.50 0.56 0.21 0.37 specimen 2 7.79 6.39 134 4.73 1.54 3.13 2.16 1.23 0.61 0.49 0.16 0.46 specimen 3 7.79? 132 4.30 1.35 3.44 1.89 1.26 0.55 0.39 0.16 0.44 specimen 4 7.65 6.22 119 4.00 1.58 3.20 1.46 1.27 0.52 0.49 0.17 0.36 specimen 5 8.07? 139 4.57 1.70 3.31 1.95 1.43 0.57 0.51 0.18 0.43 specimen 6 7.41 5.75 123 3.61 1.39 2.65 1.37 1.37 0.49 0.52 0.19 0.38 specimen 7 7.70 6.1 159 4.09 1.68 3.17 1.51 1.34 0.53 0.53 0.17 0.37 specimen 8 7.78? 136 4.34 1.45 3.14 1.85 1.19 0.56 0.46 0.15 0.43 mean 7.63 6.00 136 4.09 1.55 3.09 1.61 1.32 0.53 0.50 0.17 0.39 standard deviation 0.50 0.43 12.63 0.50 0.13 0.26 0.40 0.16 0.04 0.05 0.02 0.06 P. matthieui sp. nov.

holotype 6.11 6.69 145 3.21 1.37 2.68 1.19 1.15 0.52 0.51 0.19 0.37 paratype 1 6.89 7.15 168 3.44 1.55 2.88 1.15 1.23 0.50 0.54 0.18 0.33 paratype 2 6.75 6.85 142 3.24 1.37 3.00 1.24 1.09 0.48 0.46 0.16 0.38 paratype 3 6.69 7.16 187 3.29 1.45 2.98 1.20 1.03 0.49 0.49 0.15 0.36 paratype 4 6.53 6.61 152 2.96 1.45 2.88 0.96 1.21 0.45 0.50 0.18 0.32 paratype 5 6.71 6.98 160 3.33 1.60 2.93 1.04 1.20 0.50 0.54 0.18 0.31 paratype 6 6.49 7.05 164 3.33 1.49 2.83 1.19 1.07 0.51 0.53 0.17 0.36 paratype 7 6.82 6.77 181 3.47 1.62 2.96 1.19 1.19 0.51 0.55 0.17 0.34 paratype 8 6.41 6.72 164 3.02 1.46 2.90 1.00 1.20 0.47 0.50 0.19 0.33 ......continued on the next page Specimen d wn rn h ah aw sp u h/d ah/aw u/d sp/h mean 6.60 6.89 162.56 3.25 1.48 2.89 1.13 1.15 0.49 0.51 0.17 0.35 standard deviation 0.24 0.21 15.08 0.17 0.09 0.10 0.10 0.07 0.02 0.03 0.01 0.02 P. aubertdelaruei sp. nov.

holotype 5.44 6.31? 3.28 1.42 2.18 1.19 1.18 0.60 0.65 0.22 0.36 paratype 1 5.42 6.09? 2.32 1.29 2.08 0.61 1.71 0.43 0.62 0.32 0.26 paratype 2 5.20 5.73? 2.40 1.23 2.07 0.71 1.51 0.46 0.59 0.29 0.30 mean 5.35 6.04? 2.67 1.31 2.11 0.84 1.46 0.50 0.62 0.27 0.31 standard deviation 0.14 0.29? 0.53 0.10 0.06 0.31 0.27 0.09 0.03 0.05 0.05 P. paraminderae sp. nov.

holotype 5.86 6.26 199 3.52 1.06 2.40 1.76 0.62 0.60 0.44 0.11 0.50 paratype 1 5.67 6.31 ~160 3.26 1.01 2.21 1.53 1.09 0.58 0.46 0.19 0.47 paratype 2 5.73 5.96 ~192 3.03 0.95 2.43 1.43 0.78 0.53 0.39 0.14 0.47 paratype 3 5.97 6.08 193 3.04 0.98 2.39 1.38 0.79 0.51 0.41 0.13 0.45 paratype 4 5.57 5.81 ~162 3.00 0.86 2.35 1.38 0.58 0.54 0.36 0.10 0.46 paratype 5 5.47 6.02 237 2.98 0.96 2.35 1.45 0.79 0.54 0.41 0.14 0.49 paratype 6 5.49 6.12 198 3.20 0.98 2.34 1.58 0.86 0.58 0.42 0.16 0.49 paratype 7 5.50 6.58 ~166 3.22 0.88 2.31 1.75 0.76 0.59 0.38 0.14 0.54 paratype 8 5.03 6.22 ~202 2.99 0.93 1.75 1.48 1.11 0.59 0.53 0.22 0.49 mean 5.59 6.15 189.89 3.14 0.96 2.28 1.53 0.82 0.56 0.42 0.15 0.49 standard deviation 0.27 0.22 24.42 0.18 0.06 0.21 0.15 0.18 0.03 0.05 0.04 0.03 ......continued on the next page

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.

FIGURE 34. Pseudolibera parva sp. nov. A – C. Holotype (MNHN 25679), apical views; A. General view; B. Sculpture of the protoconch and early teleoconch; C. Sculpture of the late teleoconch; D. Non-type specimen (station Mk 12), showing a more tightly coiled spire. Scale bars: A = 1 mm; B = 0.4 mm; C = 0.2 mm; D = 2 mm.