Five new species of Turbonilla Risso, 1826 (Gastropoda, Heterobranchia, Pyramidellidae) found off the northeast coast of Brazil º 13 º
Author
S
Author
Absalão, Ricardo Silva
Author
Santos, Franklin Noel
Author
Oliveira, Deusinete
text
Zootaxa
2003
235
1
11
journal article
51313
10.5281/zenodo.156627
7372a5ed-10c7-4052-b231-a4d58c976648
11755326
156627
Turbonilla megascymna
n. sp.
(
Figs. 47
)
Description: Shell small, conical to subcylindrical, fragile, white, lustrous. Teleoconch whorls strictly convex. Suture well impressed, oblique, almost straight. Protoconch heterostrophic, planispiral with nucleus partially immersed in teleoconch, diameter
323 m
in
holotype
. Axial ribs stout, moderately low, orthocline, about 16 on body whorl of
holotype
; interspaces as wide as ribs or narrower, disappearing at periphery of last whorl. Spiral ridges of minute pits present over axial ribs and interspaces on the subsutural region, only visible under very high magnification. Base rounded. Aperture ovalpyriform. Columella arcuate. Outer lip fine. No umbilical fissure.
FIGURES 17. 13.
Turbonilla virgulinoi
n. sp.
, holotype (MNRJ 9823). 1: whole shell, length 1.8 mm; 2: base detail; 3: protoconch detail. Scale bar = 100 µm.
47.
Turbonilla megascymna
n. sp.
, holotype (IBUFRJ 12703). 4: whole shell, length 2.3 mm; 5: protoconch detail; 6: base detail; 7: spiral microsculpture. Scale bar = 100 µm.
Dimensions:
Holotype
with 4.5 teleoconch whorls; height
2.3 mm
; width
0.6 mm
.
Type
material:
Holotype
IBUFRJ 12703.
Paratype
UFPE 4440,
Paratype
MORG 41057. All
paratypes
from
08º42’S
34º44’W
, # 15 REVIZEE,
465 m
depth, Rv. “Natureza” coll., off Pernambuco State, northeast coast of
Brazil
,
25/iii/2000
.
Type
locality:
06º57’32”S
34º29’22”W
, #7 REVIZEE,
750 m
depth, Rv. “Natureza” coll., off Paraíba State, northeast coast of
Brazil
,
29/xi/2001
.
Distribution: Restricted to the Northeast Brazilian coast from between Pernambuco (08o S) and Paraíba States (6o S).
Etymology: From
megascymna
is composed by two parts:
mega
(L) for large, and
scymna
(L.) an allusion to a young animal = protoconch, in reference to the large size of the protoconch.
Remarks:
Turbonilla enna
Bartsch
in
Dall, 1927
, (Pimenta & Absalão in press: fig. 35 [
holotype
]) is the most similar species in the western Atlantic to
T. megascymna
. However,
T. megascymna
has more convex whorls with lower and lessdefined axial ribs than
T. enna
.
Moreover,
T. enna
has interspaces as wide as the ribs, and the ribs stop abruptly at the periphery of body whorl while in
T. megascymna
the interspaces are twice or more as wide as the ribs, and the axial ribs disappear at the base. Finally, the protoconch of
T. megascymna
is significantly larger than that of
T. enna
.