Siratus pointieri, Merle & Garrigues, 2011

Merle, Didier & Garrigues, Bernard, 2011, Description of four new species of Muricidae (Mollusca, Gastropoda) from the Philippines and the Caribbean area, Zoosystema 33 (4), pp. 557-575 : 570-573

Siratus pointieri n. sp.

( Figs 8A, B ; 10A )

TYPE MATERIAL. — Holotype ( MNHN. IM.24631); 3 paratypes (Coll. BG).

TYPE LOCALITY. — Dominican Republic. Las Salinas, on coarse sandy bottom, 230-245 m deep.

OTHER MATERIAL EXAMINED. — Dominican Republic. Las Salinas, 1 specimen (Coll. JPP).

Martinique. 250 m deep, 1 specimen (Coll. RD).

ETYMOLOGY. — Named in honour of Jean-Pierre Pointier.

DESCRIPTION OF HOLOTYPE

Protoconch paucispiral, of 2.0 whorls, 1.0 mm in diameter, surface ornamented with granules. Teleoconch globular, 57.7 mm high, 28.9 mm wide. Spire moderately elongate, of 6.75 whorls. Last (7th) whorl 78.2% of teleoconch height. Apical angle 63.5°. Spiral sculpture of well-marked primary cords on early teleoconch whorls; fine, poorly defined primary cords on later whorls. First and second whorl: appearance of IP, P1, P2 and P3; third whorl: appearance of adis; fourth whorl: appearance of abis and s1; fifth whorl: appearance of s2; sixth whorl: appearance of s3 and P4; seventh (last) whorl: IP, adis and abis on infrasutural ramp, P1 to P6, s1 to s6 on convex part of whorl, ADP and MP poorly developed on siphonal canal. P1, P2, P3, s3, P4, s4, P5, s5, P6, s6 poorly developed and equivalent. Numerous fine threads on last whorls. Axial sculpture of 11 protovarices (axial ridges occurring before distinction between true varices and intervariceal ribs) on first whorl. On second whorl: 10 protovarices. On third whorl: appearance of three major varices and six intervariceal ribs (two to three between each pair of varices). On fourth whorl: nine intervariceal ribs (three between each pair of varices). On sixth whorl: six intervariceal ribs (two between each pair of varices). On seventh whorl: four intervariceal ribs (two between each pair of varices). Intervarices more and more prominent from the fifth whorl onwards. Intervariceal nodules more developed on P2 and P3. P1 spine short, present on third to sixth whorls, disappearing on seventh whorl. Short spine on MP disappearing on last varix.Aperture oval, 35.3% of diameter, 22.3% of height (including siphonal canal). Columellar lip with two knobs abapically. Columellar rim partially erect, adherent adapically. Anal sulcus present. Parietal callus well-developed. Internal crenulations occurring between each pair of primary cords. Siphonal canal up to 50% of aperture length, bent dorsally and towards the right. Colour cream to orange. Intervariceal spaces orange with three clear brown spiral bands slightly marked, darker on varices and on intervariceal nodes. First brown spiral band covers P2 and P3; second band covers P4 and P5; third band covers P6 and s6. Operculum with apical nucleus. Animal and radula unknown.

B

DD

INTRASPECIFIC VARIATIONS

The number of protoconch whorls varies from 2.0 to 2.1 (four specimens studied). The number of protovarices varies from 12 to 14 on the first whorl and from 10 to 11 on the second whorl. The spire height represents 49-53% of the total height. The aperture width represents 35-38% of the diameter.

INTERSPECIFIC COMPARISON

Siratus pointieri n. sp. may be compared to three recent species: 1) Siratus cailleti (Petit de la Saussaye,1856) from Martinique (250 m deep), Desirade (220-250 m deep) and Saba Bank (200m); 2) Siratus motacilla (Gmelin, 1791) from Martinique (70 m deep) and St- Vincent (171 m deep) and Barbados (100 m deep); and 3) Siratus kugleri (Clench & Pérez Farfante, 1945) from Guadeloupe (40 m deep) and Cuba (100 m deep). Our comparison is based on 55 specimens of S. cailleti , 45 specimens of S. kugleri and 7 specimens of S. motacilla . Siratus motacilla ( Figs 9A ; 10C ) is distinguished by its paucispiral protoconch of 1.5 whorls, and by its shorter spire. Regarding the axial sculpture, the total number of protovarices on first and second whorls is generally higher, varying from 17 to 14 in S. motacilla , instead of from 14 to 10 in S. pointieri n. sp. The spiral sculpture consists of thick, strongly developed cords on the last whorl in S. motacilla , whereas it consists of very fine cords in S. pointieri n. sp. On the siphonal canal, ADP and MP cord spines are present in adults of S. motacilla , whereas they are absent in S. pointieri n. sp. The colour pattern of S. motacilla bears brown bands between P1 and P2, P3 and P4 and between P5 and P6. These brown bands are absent in S. pointieri n. sp. Siratus cailleti ( Figs 9B ; 10B ) is also distinguishable by its paucispiral protoconch of 1.5 to 1.7 whorls and by its shorter spire. Regarding the axial sculpture, the total number of protovarices on the first and second whorls is generally higher, varying from 17 to 12 in S. cailleti , instead of from 14 to 10 in S. pointieri n. sp. As for S. motacilla , the spiral sculpture consists of thick, strongly developed cords on the last whorl in S. cailleti , whereas it consists of very fine cords in S. pointieri n. sp. The shell colour is whitish in S. cailleti , instead of cream to orange in S. pointieri n. sp. Siratus kugleri differs by its protoconchs of 1.5 whorls instead 2 whorls in S. pointieri n. sp. Siratus kugleri also differs by the posterior part of the outer lip which is thickened and angulose ( Fig. 9C, D ). The adults of S. kugleri display a spiny MP ( Fig. 9C, D ), while this cord spine is missing in the adults of S. pointieri n. sp. ( Fig. 8B ). On the last whorl of S. pointieri n. sp., the primary, secondary and tertiary cords tend to have a similar small size. In S. kugleri , the tertiary cords are missing and the major cords (primary cords and secondary cords s2, s3, s4 and s5) are well developed. The colour of the shell background of S. kugleri varies from creamy to more or less brown with sometimes darker spiral bands, but it is never orange as in S. pointieri n. sp.

Figures

FIG. 8. — Primary cords and internal denticles of the outer lip of Siratus pointieri n. sp.: A, paratype (juvenile), Coll. BG, Las Salinas, Dominican Republic (H: 53.4 mm); B, holotype (adult) MNHN.IM.24631, Las Salinas, Dominican Republic (H: 57.7 mm). Scale bar: 10 mm.

FIG. 10. — Protoconch and first teleoconch whorl of Siratus pointieri n. sp., S. cailleti (Petit de la Saussaye,1856), S. motacilla (Gmelin, 1791) and S. kugleri (Clench & Pérez Farfante, 1945): A, S. pointieri n. sp., paratype, Coll. BG, Las Salinas at 250 m deep, Dominican Republic; B, S. cailleti, Coll. BG, Marie Galante at 250 m deep, Guadeloupe; C, S. motacilla, Coll. BG, Martinique. D, S. kugleri, Coll. BG, Cuba, at 100 m deep. Scale bar: 1 mm.

FIG. 9. — Primary cords and internal denticles of the outer lip of Siratus cailleti (Petit de la Saussaye, 1856), Siratus motacilla (Gmelin, 1791) and Siratus kugleri (Clench & Pérez Farfante, 1945): A, S. cailleti, Coll. BG, Marie Galante Island at 250 m deep, Guadeloupe (H: 59.9 mm); B, S. motacilla, Coll. BG, Martinique (H: 52 mm); C, D, S. kugleri, Coll. BG, Cuba, at 100 m deep (H: 53.7 mm). Scale bar: 10 mm.