Revision of the deep-sea Eulimidae (Gastropoda, Caenogastropoda) from off Northeast Brazil
Author
Souza, Leonardo Santos De
Setor de Malacologia, Departamento de Invertebrados, Museu Nacional-Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Author
Pimenta, Alexandre Dias
Setor de Malacologia, Departamento de Invertebrados, Museu Nacional-Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. & alexpim @ mn. ufrj. br; http: // orcid. org / 0000 - 0001 - 7001 - 5820
alexpim@mn.ufrj.br
Author
Barros, José Carlos Nascimento De
Laboratorio de Malacologia, Departamento de Pesca e Aqüicultura, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil. mundovan 6 @ yahoo. de; http: // orcid. org / 0000 - 0002 - 8476 - 6171
mundovan6@yahoo.de
text
Zootaxa
2021
2021-02-16
4927
4
451
504
journal article
8069
10.11646/zootaxa.4927.4.1
065cd936-3e5f-45f8-ac7f-2d530aab8b4e
1175-5326
4542923
AED51D9E-1751-4010-A8E1-B72AE428821A
Eulima
sp. 1
(
Figure 8
A–I)
Material examined.
Brazil
:
Rio Grande do Norte
: REVIZEE
Nordeste
(
04°51′00″S
35°06′00″W
,
375 m
), coll.
RV
Natureza
,
24/xi/2001
:
MNRJ 29631
† [1 dd],
MNRJ 35215
† [1 dd]
.
Description.
Shell conical, apex rounded, reaching about
6.4 mm
long,
1.6 mm
wide. Larval shell with about 2.5 whorls,
290 µm
wide,
370 µm
in height; smooth, transition to teleoconch marked by a subtle incremental scar. Teleoconch with about 7.5 whorls, almost flat; suture shallow, slightly impressed, sloping; surface glossy and smooth; incremental scars weak, appearing at irregular intervals. Last whorl about 50% of the shell length; base elongated, slightly rounded outline, connected close to the most anterior region of the aperture. Aperture high, narrow, pear shaped, acute posteriorly and rounded anteriorly; outer lip thin, slightly sinuous, opisthocline, slightly projecting near the suture and slightly retracting in the distal region; inner lip sinuous, sloping and well demarcated. Not umbilicate. Shell vitreous or whitish, with a brownish spiral band at the suture of the larval shell.
Measurements.
MNRJ 29631, 10 whorls, SL=
6.4 mm
; BWL=
3.2 mm
; AL=
2.3 mm
; SW=
1.6 mm
; AW= 1.0 mm.
Remarks.
The shell surface of the two specimens examined is corroded (
Figure 8E
) and at first, it seems that it presents a sculpture of axial lines, like some species in the genera
Melanella
Bowdich, 1822
and
Niso
Risso, 1826
. However, this is an artifact as examined in SEM and there are only incremental scars (
Figure 8E
). The general shape and the aperture are more similar to
Eulima
s.s.
Other
Eulima
species that resemble
Eulima
sp. 1 are
E. psila
(
Figure 6
A–M) and
E. grimaldii
(
Figure 6P, Q
), both with a brownish spiral band at the protoconch. However,
Eulima
sp. 1 differs from
E. psila
by features of the protoconch, which has a smaller number of whorls (2.5
vs.
3.5 in
E. psila
) and is shorter (
370 µm
vs.
420 µm
), and by the outline of the outer lip, which is slightly protruding in
E.
sp. 1 (
Figure 8G
) and straight in
E. psila
(
Figure 6I
).
Eulima
sp. 1 also differs from
E. grimaldii
by features of the protoconch, which has less convex whorls in
E.
sp. 1 (see
Figure 8H
and
Bouchet & Warén 1986
: figure 93) and a smaller number of whorls (2.5
vs.
3.3 in
E. grimaldii
). Furthermore, the body whorl comprises 50% of the shell length in
E.
sp. 1 and 40% of the shell length in
E. grimaldii
, and the aperture is relatively wider and higher in
E.
sp. 1 comparing shells with a similar number of whorls (AL=
2.3 mm
, AW= 1.0 mm
vs.
AL=
1.6 mm
, AW=
0.7 mm
,
holotype
of
E. grimaldii
).
Eulima
sp. 1 can also be distinguished from
Eulima incolor
(
Figure 5F, G
) by the brownish spiral band on the protoconch, which is not present in
E. incolor
, and by the presence of several incremental scars on the teleoconch, while
Bouchet & Warén (1986)
described that
E. incolor
does not present any incremental scar on the teleoconch.
FIGURE 8.
A–I.
Eulima
sp. 1. A, B. MNRJ 29631. C–I. MNRJ 35215. B, H. Detail of protoconch, frontal view. E. Detail of teleoconch surface. I. Detail of protoconch, apical view. Scale bars: A, C, D= 1.0 mm; B= 200 µm; E, H, I= 100 µm; F, G= 500 µm.
Despite the differences mentioned above, we refrain to name
Eulima
sp. 1 as a new species because of the almost inconspicuous features of the species. Most species of
Eulima
s.s.
are very similar to each other, especially those that do not have a colored teleoconch and we prefer to leave this species undescribed until more samples become available.
Geographical distribution.
Brazil
:
Rio Grande do Norte
.
Bathymetric distribution.
375 m
.