Siphovasum Rehder & Abbott, 1950

Vermeij, Geerat J., 2024, Shell-based genus-level reclassification of the Family Vasidae (Mollusca: Neogastropoda), Zootaxa 5405 (4), pp. 526-544 : 534

Genus Siphovasum Rehder & Abbott, 1950

Type species. Vasum (Siphovasum) latiriforme Rehder & Abbott, 1951 ; by original designation Recent , southern Gulf of Mexico, deep water ( Fig. 5 ).

Diagnosis. Shell fusiform elongate, solid, small, length to 60 mm; spire high, sutures impressed; axial sculpture consisting of high, rounded, long ribs, not forming nodes or tubercles on upper part of last whorl; spiral sculpture consisting of high, sharp cords; two basal cords on siphonal canal enlarged and forming rows of short spines; additional cords present more distally on siphonal canal; umbilicus absent; aperture small, ovate, outer lip polished only at edge and continuous with raised inner lip at posterior end of aperture; inner side of outer lip briefly lirate; columella with three thin, distant folds, most adapical fold just posterior to adapical basal spinose cord; siphonal canal about one-third length of shell, very narrow, ventrally open adapically but entirely closed distally.

Included species. Siphovasum latiriforme Rehder & Abbott, 1951 .

Material examined. ANSP 196488.

Remarks. Siphovasum is so distinctive that I have chosen to retain it as a separate genus despite the likelihood that, as Vokes (1966) has already inferred, it is a deep-water derivative of Globivasum . The continuous peristome, raised inner lip, ovate aperture, high spire, absence of spines, absence of an umbilicus, and ventrally closed distal part of the siphonal canal serve to distinguish Siphovasum from all other vasid genera. There is a very superficial resemblance with Tudivasum , which like Siphovasum has a very long (but much narrower and completely ventrally open) siphonal canal, but Siphovasum has a higher spire, very high axial ribs without spines, and an outer lip that is glazed only at the edge.

Figures

FIGURE 5. Siphovasum latiriforme (Rehder & Abbott, 1951) in dorsal (A) and apertural (B) views. Punta Colorada, Yucatan, Mexico, ANSP 196488.