Liotipoma dimorpha, 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 : 356-358

publication ID

https://doi.org/ 10.5252/z2012n2a10

DOI

https://doi.org/10.5281/zenodo.5172317

persistent identifier

https://treatment.plazi.org/id/6C26A814-FF89-1460-DA34-7DAA6EBAF7B6

treatment provided by

Felipe

scientific name

Liotipoma dimorpha
status

sp. nov.

Liotipoma dimorpha View in CoL n. sp.

( Figs 2G View FIG ; 6 View FIG ; 7 View FIG )

TYPE MATERIAL. — Holotype: LIFOU, stn 1442, Loyalty Islands, Lifou, Cape Aimé Martin, Santal Bay , 20°46.4’N, 157°02.0’E, 47 m, diving team, 13-14.XI.2000, ♂ shell, H 3.0, D 4.3 mm ( MNHN 24761 About MNHN , Fig. 6 View FIG A-D). GoogleMaps

Paratypes:same data as holotype, ♀ shell, H. 3.0, D 5.1 mm ( MNHN 24764, Fig. 7 View FIG A-D). — MONTROUZIER expedition, stn 1331, New Caledonia, Grand Koumac Reef, ♂ shell, H 2.6, D 4.0 mm ( MNHN 24763, Fig. 6 View FIG E-H). — stn 1450, ♀ shell, H 2.5, D 4.5 mm ( MNHN 24765, Fig.7 View FIG E-H).

ADDITIONAL MATERIAL. — Loyalty Islands. LIFOU, stn 1435, Loyalty Islands, Lifou, Pointe Lefèvre, Santal Bay , 20°55.2’S, 167°00.7’E, 5-30 m, 8.XI.2000, diving team, 1 immature with operculum ( MNHN, Fig. 2G View FIG ) GoogleMaps ; 1 ♂ shell at 4.6 mm diameter and 2 immature ( MNHN). — LIFOU stn 1434, Huca Hutighé, Santal Bay, 20°52.5’S, 167°08.1’E, 5-20 m, 6.XI.2000, diving team, 7 ♂♂ shells, of which the largest is 4.8 mm diameter, plus 3 immature specimens ( MNHN). — LIFOU stn 1432, Shelter Reef, Santal Bay , 20°53.5’S, 167°01.7’E, 12-32 m, 21.XI.2000, diving team, 2 mature ♂♂ shells at 4.8 mm diameter, plus 7 immature ( MNHN) GoogleMaps .

New Caledonia. MONTROUZIER expedition, stn 1331, Grand Koumac Reef, Koumac Sector, 20°40’S, 162°12’E, 55-57 m, X.1993, 2 specimens, lip not fully formed on second specimen ( MNHN, Fig. 6 View FIG E-H).

TYPE LOCALITY. — Loyalty Islands, Lifou.

DISTRIBUTION. — Lifou, Loyalty Islands, and Koumac Reef, New Caledonia.

ETYMOLOGY. — The name means two forms, with regard to sexual dimorphism.

DESCRIPTION

Male shell ( Fig. 6 View FIG )

Whorls 3.3; profile moderately high for genus; keel at periphery, slightly higher than mid-whorl; profile below shoulder evenly rounded; subtending cord not strongly projecting. Axial sculpture of strong ribs, 23-25 on last whorl in basal view; strongly spinose in early whorls, more closely spaced in final quarter whorl; spines projecting forward in direction of growth. Spiral sculpture of three cords on shoulder, beaded at intersections with axial ribs. Base with strong subtending cord, and two cords of nearly equal strength between peripheral cord and subtending cord; base with shallow pits on outer side of subtending cord. Umbilicus bordered by broad emergent cord, overridden by narrow axial ribs; umbilicus narrow, obstructed by massive extension of inner lip. Final lip massive, extending for ⅓ of final quarter whorl, with successively decreasing layers of deposition, with indentations conforming to spiral sculpture. Plane of aperture aligned to intersect axis of coiling at umbilicus. Aperture nearly radial, tongue short, triangular, in same plane as plane of aperture. H 3.0, D 4.3 mm (holotype).

Female shell ( Fig. 7 View FIG )

Of higher profile than male shell; emergent cord high on whorl (in basal view), forming protruding carination that enlarges umbilical cavity, subtending cord and first basal cord narrow, interconnected by extensions of axial ribs; tongue not projecting into umbilical cavity for specimen of Figure 7 View FIG A-D, slightly projecting in specimen of Figure 7 View FIG E-H. H 3.0, D 5.1 ( Fig. 7 View FIG A-D).

Operculum ( Fig. 2G View FIG )

Known from immature specimen, with narrow pit in center.

REMARKS

Liotipoma dimorpha n. sp. is characterised by having forward directed spines, a narrow subtending cord and an even narrower first basal cord, by which it differs from L. mutabilis n. sp., in which the subtending cord and the first basal cords are significantly broader. By that distinction it also possible to connect the female shell to the male shell and also to separate the separate the female shell from that species. The female shell of this species ( Fig. 7 View FIG ) is unlike the female shell of both L. wallisensis and L. mutabilis n. sp. in having the emergent cord positioned higher (in umbilical view), so that the tongue does not depress it. Female shells are larger than male shells, as expected. The two illustrated male shells differ in the length and direction of the tongue, but these differences are considered intraspecific. In Figure 6 View FIG A-D it is shorter and in Figure 6 View FIG E-H it is longer and not in alignment with the plane of the aperture.

MNHN

Museum National d'Histoire Naturelle

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Trochida

Family

Colloniidae

Genus

Liotipoma

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