The genera Limatula and Limea (Mollusca, Pelecypoda, Limidae) from deep waters off Brazil
Author
Oliveira, Cléo Dilnei De Castro
Departamento de Zoologia, Instituto de Biologia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Ilha do Fundão, 21941 - 590 Rio de Janeiro, Rio de Janeiro, Brasil Departamento de Zoologia, Universidade do Estado do Rio de Janeiro, Avenida São Francisco Xavier 524, Maracanã, 20550 - 900 Rio de Janeiro, Rio de Janeiro, Brasil
Author
Absalão, Ricardo Silva
Departamento de Zoologia, Instituto de Biologia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Ilha do Fundão, 21941 - 590 Rio de Janeiro, Rio de Janeiro, Brasil Departamento de Zoologia, Universidade do Estado do Rio de Janeiro, Avenida São Francisco Xavier 524, Maracanã, 20550 - 900 Rio de Janeiro, Rio de Janeiro, Brasil
text
Zootaxa
2008
2008-11-24
1940
48
58
journal article
11755334
Limea lirata
Allen, 2004
Figures 17–19
Limea lirata
Allen, 2004
: p. 2622
, fig. 36, 37, 46c.
Description:
Shell very fragile, translucent, small (height mean =
1.15mm
±
0.07 s
.d.; range
1.10–1.20mm
; n=2), height/length ratio 1.28, slightly inequilateral, little inflated, oval outline, ornamented with numerous and quite slender concentric lines that are positioned close to each other and cover the entire shell, though the lines are somewhat less evident toward the dorsal region. Axial ornamentation absent, fine internal axial ridge and groove on both valves, and not perceptible on the external side. Auricles small, subauricular sinus absent, postero and antero-dorsal margin curved in the hinge region, ventral margin strongly rounded. Prodissoconch smooth (mean 153.00µm ±
3.00 s
.d.; range
150–156 µm
; n=2), interdissoconch not distinguishable. Umbones prominent, hinge plate slender, ligamental pit rounded.
Geographic range:
Restricted to North American Basin, at 2095 meters. Adapted from
Allen (2004)
. Campos Basin (this study) represents the southernmost and the shallowest (
1044m
) record of this species, with the first record for Brazilian coast and the southeastern Atlantic Ocean.
Material examined:
IBUFRJ 17805, off
Bacia
de Campos
(
21°52'43" S
,
39°40'42" W
,
1941 m
), 26.
VI
.03, [2 valves]
.
Remarks:
Although this is a rare species in our samples, with only three valves, the characteristic concentric ornamentation with the very conspicuous fine internal axial ridge and groove on both valves makes this a distinct species.
Previously restricted to the
North American Basin
by
Allen (2004)
who collected
171 specimens
from only one station; since then, this species had not been cited.
Our
record, the first for the
Brazilian
and
South American
coast, expands the area of occurrence to the
South Atlantic
.
The characterization of the genus
Limea
includes some characters, such as axial ornamentation and marginal crenulation, which are absent in
L. lirata
. But, since, as mentioned earlier, the definition of the limid subgroups may be obscure and they probably do not form natural groups and even overlap one another, we prefer not relocate this species now, avoiding the increase of unwarranted taxonomic mistakes.