Lissodrillia verrillii (Dall, 1881) Dall, 1881

Fallon, Phillip J., 2016, Taxonomic review of tropical western Atlantic shallow water Drilliidae (Mollusca: Gastropoda: Conoidea) including descriptions of 100 new species, Zootaxa 4090 (1), pp. 1-363 : 256-258

Lissodrillia verrillii (Dall, 1881) , new combination

(Plate 130)

Pleurotoma (Drillia) Verrillii Dall, 1881: 68 . Dall (1885: 239).

Drillia Verrillii (Dall, 1881) : Tryon (1884: 213 [list]); Dall (1889a: 93, pl. 11, fig. 2); Dall (1889b: 98, pl. 11, fig. 2). Drillia verrillii (Dall, 1881) : Maury (1922: 151 [list]).

Cerodrillia (Cerodrillia) verrilli [sic] (Dall, 1881): Abbott (1974: 272, spec. & fig. 3030). Cerodrillia verrilli [sic] (Dall, 1881): Turgeon et al. (1988: 96 [list]).

Cerodrillia verrillii (Dall, 1881) : Turgeon et al. (1998: 102 [list]); Williams (2005; 2006; 2009: 1534).

Type material. Dall (1881: 68) mentioned only a single 5.5 x 1.75 mm specimen from R/V Blake Sta. 19 off Bahia Honda, Cuba, in his description. Later, he identified a lot from R/V Blake Sta. 20, also off Bahia Honda, as this species (Dall, 1889a: 93). Since lots were sometimes split between the Smithsonian and Museum of Comparative Zoology, both museums were searched for Blake specimens from both stations. An on-line database search yielded 3 lots at the MCZ (MCZ 7083, 72401 & 7084), and a drawer search yielded a single lot at the Smithsonian (USNM 87457), all of which were collected at either locality and identified as this species. The following table is a summary of the known syntypes of Lissodrillia verrillii (Dall, 1881) :

MCZ 7083: out on loan but a length measurement and photograph of the specimen in this lot was provided by Peter Stahlschmidt. It agrees with Dall’s description but is smaller, 4.4, not 5.5 mm (Pl. 130 Fig. 1 ).

MCZ 72401: also from R/V Blake Station 19, was out on loan and could not be examined. The on-line database lists two specimens in this lot. It is believed they were originally in MCZ 7083, which was recorded as having three specimens in the MCZ register, but later separated.

MCZ 7084: out on loan but a photograph (no measurement) was provided by John Tucker. The specimen in the photo does not match Dall’s description of L. verrillii but is instead Syntomodrillia lissotropis (Dall, 1881) . R/V Blake Station 20 is the type locality of S. lissotropis . This specimen is a paralectotype of S. lissotropis .

USNM 87457: was examined directly and matches Dall’s description (Pl. 130, Fig. 2), except that it is smaller, 5.1, not 5.5 mm.

None of the examined specimens exactly match the 5.5 mm length described by Dall. The drawing in Dall (1889a: pl. 11, fig. 2) is very poor, but as explained by Dall, “These shells are so very small and polished that it is extremely difficult for an artist in pure line-work to represent them adequately.” (Dall, 1889a: 92). Since the length measurements of the examined shells do not agree precisely with Dall’s measurement, and inasmuch as all lots were not examined, no lectotype designation is made here.

Type locality. R/V Blake Station 19, off Bahia Honda, [Artemisa Prov., formerly Pinar del Rio Prov.] Cuba, 23°3'0"N, 83°10'30"W, in 310 fms [567 m].

Information on syntypes from Blake Station 20 is: off Bahia Honda, [Artemisa Prov.] Cuba, 23°02'30" N, 83°11'00"W, in 220 fms [402 m].

Range and habitat. Cuba [Artemisa Prov.], in 402 and 567 m.

Description. Shell very small (to 5.5 mm in total length), fusiform, glossy smooth, of about 6½ whorls, teleoconch whorls angular at their peripheries; the last whorl about 55% of total shell length. Sculpture of ribs; aperture narrow, anterior canal moderately long. Protoconch of 1½ smooth round inflated whorls. Axial sculpture of ribs, obsolete to nearly obsolete on shoulder near suture, strong at periphery and to suture of succeeding whorls, and to about ⅔ the distance to anterior canal on last whorl; ribs number 12 on penultimate and 5 to varix on last whorl. Ribs angular at periphery, about mid-whorl. Growth striae microscopic. Varix a thickened rib about ⅓–½- turn from edge of outer lip. Spiral sculpture absent. Sulcus marked by the absence or near absence of ribs on whorl shoulder. Outer lip thin, without axial folds, smooth, edge including anal sinus forms an uninterrupted reversed “S” curve from suture to stromboid notch, which is weak. Anal sinus a deep notch on whorl shoulder adjacent to suture, its outer edge divergent, such that its edge in congruent with that of the outer lip. Inner edge of sinus flared out, directed laterally, spout-like. Inner lip thin, margined, extends roof-like over apex of aperture, callus at anal sinus weak. Anterior canal moderately long for the genus, open, unnotched. Color white to off-white.

Remarks. Taxonomy. Lissodrillia verrillii has the characteristics of the genus: a very small glossy shell that lacks spiral sculpture, and with inner edge of anal sinus and edge of outer lip that trace a reverse “S”. Unlike its congeners, its ribs are weak to absent in the sulcus, and the inflated spire whorls are angular at their peripheries. Identification. Lissodrillia verrillii can be distinguished by its small size and inflated, angular whorls. It is similar to L. turgida , new species, which differs in possessing evenly rounded, not angular whorls. Lissodrillia verrillii also has a narrower aperture, and a varix positioned ⅓-turn from the edge of the outer lip. It is closer to the edge of the outer lip in L. turgida . Most of the other members of the genus have rather flat whorl profiles when compared to L. verrillii .

Figures

Fig. 1: ventral, lateral & dorsal views; Fig. 2: enlarged view of protoconch (not to scale); Fig. 3: apical view, V = varix, L = edge of outer lip.