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
Ophiarachna mauritiensis
de
Loriol, 1893a
[New Japanese name: Mauritius-kumohitode]
(
Fig. 9H
)
Ophiarachna mauritiensis
de
Loriol 1893a
: 32
–34, 64, pl. 24, fig. 1.—
Koehler 1898
: 120
; 1922: 335, 336.—
Bergmann 1900
: 373
.—
H. L. Clark 1909
: 128
; 1915: 300.—
A. M. Clark & Rowe 1971
: 123
.—
Price & Rowe 1996
: 78
.
Material examined.
Ie
Island
(RUMF-ZE-02069[1], RUMF-ZE-02070[1], RUMF-ZE-02071[1]): “entrance” of the “Unnamed cave”, under coral rubble, approximately
18 m
depth,
24 June 2017
.
Distribution.
Japan
,
Mauritius
. Depth range
18–
370 m
.
Remarks.
A. M. Clark & Rowe (1971)
showed three color
types
of
Ophiarachna
. Our examined specimens (RUMF-ZE-02069, 0 2070 and 02071) present intermediate feature between the
type
“A” and
type
“C”. Aboral disc of our specimens are dull brown with a few widely scattered small dark spots like
type
“A”, but they also have four distinct longitudinal dark lines on aboral arm like
type
“C”.
A. M. Clark & Rowe (1971)
suggested that
type
“C” is undescribed, but further investigation with richer materials of
Ophiarachna
is required. In this study, we tentatively identify this species as
O. mauritiensis
by virtue of their oral shields longer than wide (
H. L. Clark, 1909
). The
type
material of
O. mauritiensis
was collected from
Mauritius
, Indian Ocean, and its new discovery from Japanese water is a very large extension of its range. Given that the previously known specimens of
O. mauritiensis
has been recorded from a depth of
370 m
off
Mauritius
, the present Japanese specimens are likely to be a distinct taxon. Further morphological observations based on richer material are required.