Liotipoma magna, Mclean, 2012

Mclean, James Hamilton, 2012, New species and genera of colloniids from Indo-Pacific coral reefs, with the definition of a new subfamily Liotipomatinae n. subfam. (Turbinoidea, Colloniidae), Zoosystema 34 (2), pp. 343-376 : 358-362

Liotipoma magna n. sp.

( Figs 8 ; 9 )

TYPE MATERIAL. — Holotype: SANTO 2006, stn DS103, Vanuatu, SE Santo, off Tutuba Island , 15°34.1’S, 167°16.0’E, 70-80 m, diving team, ♂ shell, H 3.6, D 6.8 mm ( MNHN 24766 , Fig. 8 A-D).

Paratypes: SANTO 2006, stn DS104, W Tutuba Island , 15°34.1’S, 167°16.0’E, ♂ shell, H 3.4, D 5.3 ( MNHN 24767 , Fig. 8 E-H). — SANTO 2006, stn DS105, NW Tutuba Island, 15°33’S, 167°16.7’E, 92 m, 2 ♀♀ shells ( MNHN 24768 , Fig. 9 A-D, H 3.6, D 5.7 mm; MNHN 24769 , Fig. 9 E-H, H 3.4, D 5.3 mm) .

TYPE LOCALITY. — Vanuatu, Espiritu Santo.

ETYMOLOGY. — Latin, “magnus”, large, befitting for the largest known species of Liotipoma .

DISTRIBUTION. — Known only off Espiritu Santo, Vanuatu.

DESCRIPTION

Male shell ( Fig. 8 )

Whorls 3.0; profile moderately high for genus; peripheral angulation at mid-whorl, shoulder ramp slightly convex above, profile below peripheral angulation evenly rounded. Axial sculpture of strong ribs, 32 on last whorl; spinose and projecting in early whorls, spinosity much diminished in final third whorl and axials more closely spaced in final whorl. Spiral sculpture of three low cords on shoulder; base with strong subtending cord, and two cords of nearly equal strength between peripheral cord and subtending cord; umbilicus bordered by broad, angular emergent cord, overridden by narrow axial ribs. Umbilicus partially open, partially obstructed by emergent tongue of lip; tip of tongue directed toward coiling axis. Final lip massive, extending for ⅓ of final quarter whorl, showing about twenty successively decreasing layers of deposition, lip conforming to spiral sculpture; tongue extending half the diameter of aperture on previous whorl, showing similar layers of deposition decreasing in extent. H 3.6, D 6.8 mm (holotype); H 3.4, D 5.3 mm (MNHN 24767, stn DS104).

Female shell ( Fig. 9 )

Two specimens from Espiritu Santo have holes in the shell in the apical area but are determined as females of this species for their large size and matching sculpture. Both have short tongues that serve to increase the volume of the umbilical cavity. The specimen in Figure 9 A-D lacks a projecting tongue; that of Figure 9 E-H is higher in profile and has a very narrow extension of the lip that extends to the umbilical edge. Both specimens show a larger volume for the umbilical cavity than the male shells in the tilted views. H 3.4, D 5.3 mm ( Fig. 9 E-H).

Operculum and radula

Unknown.

REMARKS

This is the largest known species of Liotipoma . The closest comparison is with L. splendida n. sp. ( Fig. 13 A-D), which is smaller in diameter by 1.5 mm, and has a comparable number of axial ribs. Liotipoma magna n. sp. differs in having a short, triangular apertural tongue directed toward the coiling axis, rather than the broad, stubby tongue directed in advance of the aperture of L. splendida n. sp. The two male shells differ in detail of the umbilical cavity, as do the female shells. The differences are considered to be intraspecific.

This species is unusual for Liotipoma in differing from the general observation that female shells are larger than male shells because the first illustrated male shell ( Fig. 8 A-D) is greater in diameter by more than 1 mm than both female shells. The female shell of Figure 9 E-H has the high profile expected in a female shell.

This is the only species so far known from Vanuatu.

Figures

FIG. 8. — Liotipoma magna n. sp., male shells: A-D, holotype (MNHN 24766, stn DS103), off W side Tutuba Island, Espiritu Santo, Vanuatu,70-80 m, H 3.6, D 6.8 mm; E-H, Paratype (MNHN 24767, stn DS104),80 m off W side Tutuba Island,Espiritu Santo, Vanuatu, H 3.4, D 5.3 mm. Scale bars: 1 mm.

FIG. 9. — Liotipoma magna n. sp., female shells: A-D, paratype (MNHN 24768,stn DS105), off NW side Tutuba Island, Espiritu Santo, Vanuatu,92 m,H 3.6, D 5.7 mm;E-G, paratype,off W side Tutuba Island (MNHN 24769,stn DS105),off NW side Tutuba Island,Espiritu Santo, Vanuatu, 92 m, H 3.4, D 5.3 mm. Scale bars: 1 mm.

FIG. 13.— A-D, Liotipoma splendida n. sp.holotype,male shell (MNHN 24772,stn 1269), Doiman Reef,Touhou Sector,New Caledonia, 15-20 m, H 3.2, D 5.1 mm; E-H, Liotipoma clausa n. sp. Holotype, immature male shell (LACM 3110, stn 91-189), Herald Pass, Great Astrolabe Reef, Fiji, 15 m, H 3.0, D 4.2 mm. Scale bars: 1 mm.