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
Limatula confusa
(
Smith, 1885
)
Figures 6–9
Lima confusa
Smith, 1885
: p. 292
, pl. XXIV, fig. 6, 6a.
Limatula confusa
:
Stuardo, 1968
: pl. 16, fig. 88;
Abbott, 1974
: p. 454
.
Description:
Shell fragile, white, small (height mean =
3.28mm
±
2.06 s
.d.; range
1.10–6.30mm
; n=14), height/length ratio 1.41, equivalve, slightly unequilateral, very inflated, outline suboval, thin axial ribs cover entire shell, but axial ribs not evenly spaced. The axials are closer to each other on the dorsal side, and slowly increase in the distance between them towards the ventral side, very fine concentric striae present, forming small nodules where they cross the axial ribs. Internal axial ridge absent. Auricles small, with few ornaments, subauricular sinus present, ventral region rounded or angled. Prodissoconch smooth (mean
177.50µm
±
16.69 s
.d.; range
160–200 µm
; n=14), interdissoconch hardly distinguishable in some specimens (mean 805.00µm ±
33.38 s
.d.; range
760–860 µm
; n=14). Umbones prominent, hinge plate large, ligamental pit broad, triangular.
Geographic range:
North Carolina to the West Indies, off Azores, Northeast
Brasil
, off
Pernambuco State
. Depths ranging between 60 to 2650 meters. Adapted from
Abbott (1974)
,
Rios (1994)
and
Allen (2004)
. Campos Basin (this study), is the southernmost record in the Atlantic Ocean.
Material examined:
IBUFRJ 17802, off
Bacia
de Campos
(
21°57'27" S
,
39°40'34" W
,
1942 m
), 27.
VI
.03, [1 valve]; IBUFRJ 17803, off
Bacia
de Campos
(
21°52'41" S
,
39°46'17" W
,
1688 m
), 26.
VI
.03, [1 valve]; IBUFRJ 17804, off
Bacia
de Campos
(
22°11'17" S
,
39°43'45" W
,
1950 m
), 25.XI.02, [1 valve]; IBU- FRJ 17807, off
Bacia
de Campos
(
21°58'36" S
,
39°46'30" W
,
1700 m
), 10.
VIII
.01, [1 valve]; IBUFRJ 17812, off
Bacia
de Campos
(
22°31'37" S
,
39°55'14" W
,
1630 m
), 16.
VI
.03, [1 valve]; IBUFRJ 17813, off
Bacia
de Campos
(
22° 24'32" S
,
39°57'28" W
,
1050 m
), 20.XI.02, [1 valve]; IBUFRJ 17814, off
Bacia
de Campos
(
22°36'12" S
,
39°58'23" W
,
1670 m
), 13.
VI
.03, [1 valve]; IBUFRJ 17815, off
Bacia
de Campos
(
22°31'28" S
,
40°03'50" W
,
1043 m
), 18.
VI
.03, [1 valve]; IBUFRJ 17816, off
Bacia
de Campos
(
21°57'27" S
,
39°40'34" W
,
1942 m
), 27.
VI
.03, [1 valve]; IBUFRJ 17817, off
Bacia
de Campos
(
22°04'45" S
,
39°46'32" W
,
1643 m
), 27.
VI
.03, [1 valve]; IBUFRJ 17818, off
Bacia
de Campos
(
22°11'04" S
,
39°47'05" W
,
1650 m
), 25.XI.02, [1 valve]; IBUFRJ 17819, off
Bacia
de Campos
(
22°10'54" S
,
39°52'19" W
,
1050 m
), 10.
XII
.02, [1 valve]; IBU- FRJ 17820, off
Bacia
de Campos
(
22°05'45" S
,
39°45'55" W
,
1730 m
), 09.
V
.02, [1 valve]; IBUFRJ 17821, off
Bacia
de Campos
(
22°05'04" S
,
39°50'02" W
,
1230 m
), 09.
V
.02, [1 valve]; IBUFRJ 17822, off
Bacia
de Campos
(
22°39'34" S
,
40°08'22" W
,
1200 m
), 15.
V
.02, [1 valve]
.
Remarks:
Apparently this species has not been collected since its description (from the Challenger Expedition material), and a part of the
type
series was destroyed (
Allen 2004
, p. 2644). However, the description and especially the
type
illustration in plate 24, figs. 6-6a (
Smith 1885 p. 292
), are good enough to allow us to identify it. In our description we include details that were not mentioned in the original description because of the limitations in optics of the period.
Limatula margaretae
Allen, 2004
is the most similar taxon to
L. confusa
in the Atlantic basin: both species share the same outline and
type
of ornamentation, but can be distinguished by the presence of axial ribs over all the shell including the auricles in
L. confusa
(fig. 6–7), while the auricles are devoid of axial ribs and the central and postero-central axial ribs are barely visible in
L. margaretae
.
Besides that, the umbones at
L. margaretae
are more prominent than in
L. confusa
.