A new subgenus and three new species of Brazilian deep water Olivella Swainson, 1831 (Mollusca, Gastropoda, Olivellidae) collected by the RV Marion Dufresne in 1987
Author
Absalão, Ricardo S.
Departamento de Biologia Animal e Vegetal, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Francisco Xavier 524, Maracanã, Rio de Janeiro, RJ, CEP 20550 - 900 (Brazil) Departamento de Zoologia, Instituto de Biologia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, RJ- 21941 - 570 (Brazil) absalao @ biologia. ufrj. br
Author
Pimenta, Alexandre D.
Departamento de Zoologia, Instituto de Biologia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro, RJ- 21941 - 570 (Brazil) alexpim @ biologia. ufrj. br.
text
Zoosystema
2003
25
2
177
185
journal article
10.5281/zenodo.5757059
1638-9387
5757059
Olivella
(
Anasser
)
careorugula
n. sp.
(
Fig. 1
G-I)
TYPE MATERIAL. —
Holotype
:
MNHN
;
paratypes
(two shells in each lot):
MNRJ 8913
,
8915
;
IBUFRJ 11074
; MORG 41036; MZSP 35529; ANSP 410280. All type material from the type locality.
TYPE
LOCALITY. — South of Cabo Frio,
Rio de Janeiro State
,
Brazil
, MD-55, stn CB105,
23°47’S
,
042°10’W
,
610 m
.
OTHER MATERIAL EXAMINED. — MD-55, stn CB105,
23°47’S
,
42°10’W
,
610 m
,
2.VI.1987
,
41 spec.
(
MNHN
)
;
MD-55, stn CB105,
23°47’S
,
42°10’W
,
610 m
,
V.1987
, 2 shells (
MNHN
)
; MD-55, stn CB97,
21°34’S
,
40°08’W
,
600 m
,
V.1987
,
1 spec.
ETYMOLOGY.— From
careo
(Latin):not; and
rugula
(Latin): fold, referring to the absence of folds or pillar structure.
DESCRIPTION
Shell medium sized (maximum length about 6.0 mm), white, semi-translucent, glossy of about 3.5 whorls. Spire of 2.5 whorls moderately tapering, comprising about 16-19% the total length. Protoconch small, rounded, not projecting above the outline of shell. The sutures are narrow and channeled visible as a spiral line due to shell translucence. In fresh specimens, there is usually an opaque white subsutural belt. Body whorl sub-cylindrical; spire whorls quite convex and very slightly stepped. Apex blunt and convex. Fasciole simple and sometimes hardly discernible. Low, light parietal callus, a bit more opaque than the shell and extending only to the end of the aperture. Pillar structure absent. Columella strongly concave at anterior end, the remainder almost straight. Yellowish chitinous operculum present.
REMARKS
Olivella careorugula
n. sp.
(
Fig. 1
G-I) is less inflated and much smaller than
O. amblya
(
Fig. 1
A-C).
Olivella ephamilla
(
Fig. 1
D-F) shares with
O. careorugula
n. sp.
the oblong outline but the spire profile of
O. ephamilla
is almost straight, giving a stepping tapering appearance, while in
O. careorugula
n. sp.
it is strongly convex. Besides that,
O. careorugula
n. sp.
bears a large subsutural white band, which is not present in the
types
of
O. ephamilla
.
The only species from western Atlantic with shells similar to
O. careorugula
n. sp.
are
O.
(
Minioliva
)
acteocina
Olsson, 1956
and
O
. (
Minioliva
)
perplexa
Olsson, 1956
(
Olsson 1956
: pl. 12, fig. 6 and pl. 16, fig. 7 respectively) from
Florida
and Bahamas-Panamá respectively. Both these
Minioliva
have higher spires and less convex whorls than
O.
(
Anasser
)
careorugula
n. sp.
Furthermore, they have a typical
Minioliva
pillar structure (
sensu
Olsson 1956
), absent in all
Anasser
n. subgen.
species.
Additionally,
Anasser
n. subgen.
seems to be a deep water southern Atlantic group while
O. acteocina
and
O. perplexa
inhabit shallow, more northernly coastal waters.
FIG. 2. — Subgenus
Olivina
d’Orbigny, 1841
;
A -C
,
Olivella hyphala
n. sp.
, holotype (MNHN);
A
, apertural view, 7.4 mm length;
B
, apex detail;
C
, plicae detail;
D
,
E
,
Olivella klappenbachi
n. sp.
, holotype (MNHN);
D
, apertural view, 5.5 mm length;
E
, apex detail. Scale bars: B, C, E, 500 µm.
We failed to find radulae in dried specimens. Despite rehydration, careful dissection and, ultimately, KOH digestion.
Olivella careorugula
n. sp.
may lack this structure.