A comprehensive taxonomic list of brittle stars (Echinodermata: Ophiuroidea) from submarine caves of the Ryukyu Islands, southwestern Japan, with a description of a rare species, Dougaloplus echinatus (Amphiuridae)
Author
Okanishi, Masanori
Author
Fujita, Yoshihisa
text
Zootaxa
2019
2019-03-25
4571
1
73
98
journal article
28099
10.11646/zootaxa.4571.1.5
4b455544-f490-4283-b51f-3bab0af22419
1175-5326
2605976
40B4CF49-C6F0-4392-B971-C90AC4768DF1
Cryptopelta
cf.
callista
H. L. Clark, 1938
(
Fig. 9E
)
Cryptopelta callista
H. L. Clark 1938
: 354
, 355, pl. 14, fig. 2; 1946: 264.—
A. M. Clark & Rowe 1971
: 88
, 89, figs 45a, 55a, b.—
Rowe & Gates 1995
: 394
.
Material examined.
Ie
Island
(RUMF-ZE-02068[1]): “entrance” of the “Unnamed cave”, under coral rubble, approximately
18 m
depth,
24 June 2017
.
Distribution.
North
western Australia
. Depth range
9–
180 m
.
Remarks.
This specimen present intermediate features of
C. calista
H. L. Clark, 1938
and
C. granulifera
.
H. L. Clark, 1909
. The features of
C. callista
are: dorsal arm plates are as wide as long on proximal portion of the arm, arms on proximal portion of the arms are flattened, peripheral edge of aboral disc on proximal portion of arms are convex, and length of arm spines are half of the corresponding arm segment. Whereas those of
C. granulifera
are: dorsal arm plates are slightly wider than long, arms on proximal portion of the arms are cylindrical, peripheral edge of aboral disc on proximal portion of arms are flat, and length of arm spines are shorter than those of
C. callista
(see also
A. M. Clark & Rowe, 1971
). Our specimen (RUMF-ZE-02068) have slightly wider dorsal arm plate on proximal portion of arms, cylindrical arms on proximal portion of arms; convex peripheral edge of aboral disc, and arm spines half length of the corresponding arm segment. Absence/presence of color band on oral arms is diagnostic character to distinguish
C. callista
and
C. granulifera
(
A. M. Clark & Rowe, 1971
)
. However, color of oral arm of our specimen have completely diluted by ethanol fixation and living color has not photographed. We here tentatively this specimen referred as
C.
cf.
callista
because its color pattern is more similar to
C. callista
.
The
type
material of
C. callista
was collected from northern
Australia
and of
C. granulifera
was collected from
Mauritius
, and occurrence of this specimen in Japanese water is an extension of their range. Given the geographical gap between
Japan
and
Australia
and
Mauritius
, they are possibly different taxa. Or, emphasis on existence of the intermediate feature of our specimen indicates that these two species are conspecific. To clarify this, further morphological observations based on richer materials and molecular analysis are required.