Otitoma philpoppei, Morassi & Nappo & Bonfitto, 2017

Morassi, Mauro, Nappo, Andrea & Bonfitto, Antonio, 2017, New species of the genus Otitoma Jousseaume, 1898 (Pseudomelatomidae, Conoidea) from the Western Pacific Ocean, European Journal of Taxonomy 304, pp. 1-30 : 24-25

Otitoma philpoppei sp. nov.

urn:lsid:zoobank.org:act:D0F62828-F675-448A-903A-73AB90576A4A

Fig. 6 I–N

Etymology

This taxon is dedicated by one of the authors (AN) to his friend the malacologist Philippe Poppe (Lapu Lapu, Philippines).

Type material

Holotype

PHILIPPINES: Mactan Island , 200 m, from local fishermen ( MNHN IM-2000-32609 ).

Paratype

FIJI ISLANDS: BORDAU 1, Stn DW1464, 18°09 ′ S, 178°38 ′ W, 285–300 m ( MNHN IM- 2000-32610).

Description

Shell cylindric-pupoid (b/l 0.39–0.40; a/l 0.55–0.59). Teleoconch consisting of 2¾–3½ whorls which are weakly and evenly convex. Last whorl with a shallowly excavated base. Whorls separated by a shallow suture, bordered by 2 closely spaced spiral cords, but lacking a distinct sub-sutural fold. Subsutural ramp shallow and concave. First teleoconch whorl with 2 closely spaced cords at suture, 1 weak cord on sutural ramp and 3 spiral cords on abapical part of whorl. On following whorl additional cords develop on sutural ramp, including 2–3 spirals more prominent than others, with 8–9 spiral cords below sutural ramp, increasing to 14–15 on last whorl. Spiral cords closely spaced, somewhat irregular in strength, rendered plicate by dense, moderately coarse incremental growth lines covering entire surface ( Fig. 6L ). Base sculptured by 14–15 spiral cords with 1 fine interstitial thread between. Axial sculpture restricted to penultimate whorl, consisting of irregularly spaced, opisthocline axial ribs, narrower than intercostal spaces, extending from suture to suture, but becoming narrower and arcuate on sutural ramp (about 13 on penultimate whorl in holotype). Aperture narrow and almost linear, but constricted at entrance to siphonal canal. Siphonal canal wide, expanding slightly distally, not notched. Inner lip covered with a thin callus and weak parietal pad. Outer lip preceded by a wide, low and rounded varix, its edge sharp, with a relatively shallow (for genus) stromboid notch. Anal sinus moderately deep, rounded, asymmetrically U-shaped, its entrance only slightly constricted by parietal pad. Protoconch domed, of 2½–2¾ whorls, smooth ( Fig. 6 M–N), diameter 0.89–0.90 mm. Color white or white with three light brownish orange bands (on sutural ramp, on base of last and penultimate whorl and on base) and aperture edged with brownish orange.

Dimensions

Holotype: 6.7 × 2.7 mm, aperture height 3.7 mm. Paratype: 5.6 × 2.2 mm, aperture height 3.3 mm.

Remarks

Otitoma philpoppei sp. nov. belongs to a morphologically distinctive group, which includes O. kecil and O. vitrea , that are rather small (about 5 mm in length), have a pupoid shape, and have similar protoconch features. The new species is comparable to O. vitrea from Mindanao, Philippines, but differs in having a much more abbreviated shell such that the last whorl represents nearly 60% of total height, and possesses more numerous raised spiral cords. Furthermore, O. philpoppei sp. nov. has distinct axial ribs on the penultimate whorl, while O. vitrea lacks axial sculpture. Otitoma philpoppei sp. nov. differs distinctly from O. kecil in its proportions (b/l 0.39–0.40 vs 0.29; a/l 0.55–0.59 vs 0.44), the presence of axial ribs on the penultimate whorl (axial sculpture is absent in O. kecil ) and the type of spiral sculpture (spiral cords closely-set and low rather than narrow, widely spaced and prominent as in O. kecil ).

Figures

Fig. 6. [next page] A–H. Otitoma crassivaricosa sp. nov. A–B. Holotype (MNHN IM-2000-32607), MUSORSTOM 9, Stn DW1218, Hiva Oa Island, Marquisas Archipelago, 9°44.5′ S, 138°50.9′ W, 125– 135 m, 9.85 × 3.7 mm. C. Teleoconch (not coated). D. Secondary spiral sculpture of the teleoconch (not coated). E–H. Protoconch (not coated). F. Microsculpture and of the protoconch (not coated). H. Color micrograph of the same protoconch. — I–N. Otitoma philpoppei sp. nov. I–J. Holotype (MNHN IM-2000-32609), Philippines, Mactan Island, 200 m, from local fishermen, 6.7 × 2.7 mm. K–N. Paratype (MNHN IM-2000-32610), BORDAU 1, Stn DW1464, Fiji, 18°09′ S, 178°38′ W, 285– 300 m. L. Teleoconch. M–N. Protoconch. — O–T. Otitoma nereidum sp. nov. O–P. Holotype (MNHN IM-2000-32611), BORDAU 1, Stn DW1464, Fiji, 18°09′ S, 178°38′ W, 285–300 m, 9.15 × 3.35 mm. Q–T. Paratype 2 (MZB 60216), BORDAU 1, Stn DW1494, Fiji, 18°55′ S, 178°29′ W, 240–319 m. R. Teleoconch. S–T. Protoconch, scale bar = 100 μm. Scale bars: C, E, R = 500 µm; D, L–N = 100 µm; F = 10 µm; K, Q = 1 mm.