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
Clathrodrillia rubrofasciata
,
new species
(
Plate 47
)
Type
material.
Holotype
31.0 x
11.3 mm
, A. Bodart! (MZSP
122061
); 2
paratypes
: 1 spec., 29.2 x
10.4 mm
, in
21–27 m
depth, off Alcobaça, Bahia State,
Brazil
, A. Bodart! (MNRJ 34634); 1 spec. 30.1 x
11.1 mm
, in
37 m
, off Campos, Rio de Janeiro State,
Brazil
, A. Bodart! (P. Stahlschmidt coll.).
Type
locality.
Off Campos, Rio de Janeiro State,
Brazil
, at
35 m
.
Range and habitat.
Brazil
(Bahia and Rio de Janeiro States). Reported from
21–
35 m
.
PLATE 47.
Clathrodrillia rubrofasciata
,
new species
. Figs. 1–3: holotype, off Rio de Janeiro State, Brazil (MZSP 122061). 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. Figs. 4–5: paratypes. Fig. 4: off Alcobaça, Bahia State, Brazil (MNRJ 34634); Fig. 5: off Campos, Rio de Janeiro State, Brazil (P. Stahlschmidt coll.).
Description.
Shell
medium (to 31.0 mm in total length), fusiform, truncated anteriorly with a constricted base at the level of the stromboid notch, tall spire and somewhat acuminate tip, short anterior canal, whorls turreted with concave sulcus, impressed sutures, round shoulders and somewhat flattened sides. Whorls total 12, last whorl 51% of total shell length; aperture narrowly oval; shell sculpture of axial ribs cut by spiral grooves.
Protoconch
of approximately 1¾–2 smooth whorls, tip partially immersed in second whorl. Beginning of teleoconch is taken at the appearance of axial ribs.
Axial sculpture
of straight axial ribs that run from suture-to-suture on spire whorls, recurved on shoulder of later whorls, evanesce below periphery of last whorl; 10–11 on penultimate and 5–7 on last whorl to varix; ribs progressively reduced in sulcus from first teleoconch to last whorl, such that only narrow crescent-shaped ridges occur on last 2–3 whorls that reflect past positions of anal sinus, some of which are raised and nodule-like. Rib crests round, becoming ridged on shoulder and in sulcus; intercostal space about as wide as the width of ribs. Irregular microscopic growth striae present on shell surface.
Varix
broad, hump-like, approximately ⅓-turn from edge of outer lip; 2–3 low axial folds present on surface of varix.
Spiral sculpture
of regularly spaced spiral grooves, 5–7 on penultimate and 12–15 on shell base below suture line to anterior fasciole; grooves override axial ribs. Anterior fasciole without distinct cords; crescent shaped striae from advancing growth present, sulcus with a few very faint spiral grooves.
Sulcus
margin demarcated by rapid drop in rib height and width; concave at its base (abapical side) and convex along the suture; ribs and growth striae crescent-shaped on later whorls, straighter on early teleoconch whorls. Faint spiral grooves in sulcus of early whorls mostly obscured by ribs and growth striae on later ones.
Outer lip
flattened, with 5 low axial folds; edge of lip traces a flattened arc along its length, smooth, not scalloped but rather lightly ruffled by the spiral groove ends; stromboid notch distinct but shallow and broad.
Anal sinus
deeply notched, round, parietal lobe forming one side; inner edge of sinus flared outward.
Inner lip
moderately wide, emarginated and with visible layers of deposition along it edge, erect anteriorly along columella, recumbent and widest on parietal wall, developed into a heavy lobe posteriorly.
Anterior canal
short but distinctly formed, open, twisted to the right at its tip when viewed ventrally, notched; fasciole not swollen, with 4–5 indistinct spiral grooves forming cords of varying widths; growth striae parallel to its edge.
Color
dirty white with a light-to-dark-brown mid-whorl spiral band and a fainter, narrower one below it confined to the intercostal spaces; with reddish-brown color between the ribs extending either side of the central band and on varix.
Remarks.
Taxonomy.
Clathrodrillia rubrofasciata
has the morphological characteristics of
Clathrodrillia
: shell with a tall spire, with a concave sulcus, strong ribs cut by spiral grooves, broad hump-like varix about ⅓-turn from the edge of the outer lip, and a protoconch of about two smooth round whorls.
Variability.
The three examined specimens have an average total length of
30.1 mm
(29.2–31.0) and an average W/
L ratio
of 0.363.
Identification.
Clathrodrillia rubrofasciata
is unique in its color pattern but somewhat similar in size and color to
C. dautzenbergi
(Tippett, 1995)
and in form to
Neodrillia princeps
,
new species
. From
C. dautzenbergi
it differs in having fewer ribs (11 versus 18–22 on the penultimate whorl) and in its color, which is reddish, not light pink. From
Neodrillia princeps
,
new species
, which is similarly colored, it differs in possessing fewer ribs (10–11 versus 15–17 on the penultimate whorl), and in lacking the fine spiral sculpture typical of that genus (fewer spiral grooves versus numerous raised threads). In coloration,
C. rubrofasciata
is similar to
Fenimorea kathyae
Tippett, 1995
but differs in having deep spiral grooves that cut the ribs.
Etymology.
The Red-banded
Clathrodrillia
, from the Latin adjectives
rubro
-, combining form of
rubra
, meaning red, and
fasciatus
, meaning banded. Named for its reddish-brown band, which is unique among its congeners.