Taxonomic review of tropical western Atlantic shallow water Drilliidae (Mollusca: Gastropoda: Conoidea) including descriptions of 100 new species
Author
Fallon, Phillip J.
text
Zootaxa
2016
4090
1
1
363
journal article
10.11646/zootaxa.4090.1.1
e6b35f5a-435e-4473-b29e-1e4d842f84b0
1175-5326
263299
203BAC25-B542-48FE-B5AD-EBA8C0285833
Lissodrillia vitrea
,
new species
(
Plate 131
)
Type
material.
Holotype
4.2 x
1.6 mm
, T. Askew! (ANSP 372158); no
paratypes
.
Type
locality.
Off Freeport, Grand
Bahama
I.,
26°31'00''N
,
078°46'30''W
, in
387 m
.
Range and habitat.
Known only from the
holotype
.
Description.
Shell
very small (
4.2 mm
), fusiform, glossy smooth, translucent; of about 6½ whorls total with slightly angular peripheries, the last about 56% of total shell length; sutures appressed. Sculpture consisting of ribs; aperture narrow, anterior canal moderately long.
Protoconch
of 1¾ smooth glossy whorls, the beginning of the first partially imbedded in the last ¾ whorl such that the protoconch appears dome-shaped.
Axial sculpture
of narrow opisthocline ribs, 12 on penultimate and 9 on last to varix, about as wide as their interspaces, obsolete on shoulder near suture, hooked from sulcus to periphery and extending obliquely to suture of succeeding whorl; to about ⅔ the distance to anterior canal on last whorl. Growth striae microscopic.
Varix
a thickened rib about ⅓-turn from edge of outer lip.
Spiral sculpture
absent.
Sulcus
band-like, narrow, flat not concave, below suture; without sculptural elements.
Outer lip
thin, without axial folds, smooth, edge forms an uninterrupted reversed “S” curve from suture to tip of anterior canal; stromboid notch not evident on
type
, which has a repaired outer lip.
Anal sinus
a deep notch on whorl shoulder adjacent to suture, its outer edge divergent, such that its edge is congruent with that of the outer lip.
Inner lip
thin, margined, extends over apex of aperture, callous at anal sinus weak.
Anterior canal
short but well defined, open, unnotched.
Color
translucent; ribs are an opaque white.
Remarks.
Taxonomy.
Lissodrillia vitrea
has the characteristics of the genus: a very small glossy shell that lacks spiral sculpture, and with the inner edge of the anal sinus and edge of outer lip that trace a reverse “S”. Unlike most of its congeners, the sulcus is devoid of ribs, which are also quite oblique for the genus.
Identification.
At
4.2 mm
this is among the smallest members of the genus.
Lissodrillia verrillii
(Dall, 1881)
is a similar size but has more convex whorls. From
Lissodrillia schroederi
(Bartsch & Rehder, 1939)
it differs in possessing more oblique ribs and a more translucent shell. From the same habitat and of a similar size but in a different genus,
Syntomodrillia lissotropis
(Dall, 1881)
differs in possessing grooves in intercostal space and on the anterior canal. This single specimen merits description as a new species because it is morphologically different than its congeners (see
Plate 132
), and adds to the morphological diversity of the genus-group. An interesting observation is that four species, all from the Florida Straits,
L. vitrea
,
L. verrillii
(Dall, 1881)
,
Bellaspira minutissima
,
new species
, and
Syntomodrillia lissotropis
(Dall, 1881)
, are very small, plain, and similar in appearance, yet each retains the diagnostic characteristics of its genus.
Etymology.
The Glassy
Lissodrillia
. The name refers to its translucent shell. From the Latin adjective
vitreus
, feminine
vitrea
, meaning resembling glass in its translucency.