Deep-water Raphitomidae (Mollusca, Gastropoda, Conoidea) from the Campos Basin, southeast Brazil
Author
Figueira, Raquel Medeiros Andrade
Author
Absalão, Ricardo Silva
text
Zootaxa
2012
3527
1
27
journal article
10.5281/zenodo.210977
8eba0512-d65c-4c36-8c30-6d629fabfff8
1175-5326
210977
Magnella extensa
(
Dall, 1881
)
(
Figs. 24–26
)
Pleurotoma
(
Bela
)
blakeana extensa
Dall, 1881
: 55
:
Dall (1889: 126, pl. 10, fig. 2)
;
Pleurotomella extensa
(
Dall, 1881
)
:
Abbott (1974: 290, ind. 3452)
;
Gymnobela extensa
(
Dall, 1881
)
:
Absalão
et al
. (2005
: 33
, fig. 92);
Rios (2009: 350, species 908)
;
Pleurotoma
(
Defrancia
)
streptophora
Watson, 1881
: 464
.
Clathurella streptophora
(
Watson, 1881
)
:
Watson (1886: 356, pl. 19, fig. 8)
.
Type
material
:
Syntypes
MCZ
7146,
MCZ
7147,
MCZ
7148.
Type
locality
: Cape San Antonio,
Cuba
,
755–1170 m
; Yucatan,
Mexico
, Blake sta. 35 (
23º 52’N
,
88º 58’W
),
1470 m
.
Material examined
:
Type
material and 18474 [1] OP II # 60; 18475 [1] OP II # 75; 18476 [2] OP II # 84; 18477 [1] OP II # 86; 18478 [1] OP I # 50A; 18479 [4] OP I # 75.
Description
: Shell oblong-biconical, white, up to
5.08 mm
long. Protoconch with about 3.5 whorls. Protoconch 1 with spiral rows of tiny crosses. Protoconch 2 with diagonal cancellation on the lower 3/4 of the whorls, and axial riblets crossed by very fine and faint spiral threads on the upper fourth. Clear-cut prototeleoconch boundary. Teleoconch with a strong subsutural spiral cord and another strong spiral cord on the upper half of the whorls. Axial sculpture consists of 14–16 axial ribs (on the fourth whorl), forming pointed nodules where they cross the spiral cords. Axial ribs extend over base. Shell surface with granules aligned spirally. Suture well marked. Base short, with nine weak spiral cordlets. Anal sinus not discernible. Outer lip relatively thick. Anterior siphonal canal oblique, very short and wide. Aperture elliptical.
Geographic distribution
: Northwest Atlantic:
Cuba
(
Dall, 1881
;
Dall, 1889
). Southwest Atlantic: Bahia, Espírito Santo and Rio de Janeiro (
Absalão
et al
., 2005
); Campos Basin, Rio de Janeiro (this paper).
Bathymetry
:
450–2076 m
(
Absalão
et al
., 2005
).
Discussion
: Our material matches well with the original illustration of the species (
Dall, 1889: pl. 10, fig. 2
). When compared directly with the
syntype
(fig. 24), our specimens show a more prominent subsutural row of nodules and a stronger spiral ornamentation on the base. We believe these differences to represent intraspecific variation.
This species was originally described as a subspecies of
M
.
blakeana
. It can be distinguished from
M
.
blakeana
by its much thinner profile, glossy surface, less numerous spiral ornamentation and strong subsutural row of nodules.