Taiwanese deep-water chitons (Mollusca: Polyplacophora) and survey of chiton fauna of Taiwan
Author
Sirenko, Boris
text
Zootaxa
2018
4422
3
301
344
journal article
30034
10.11646/zootaxa.4422.3.1
d3ab996a-3124-4733-93fd-7eadcacdc179
1175-5326
1253051
225024A4-A643-4F17-9A8D-4905DC236330
Leptochiton torishimensis
(
Wu & Okutani, 1984
)
(
Figs 23–25
)
Hanleyella tоrishimensis
Wu & Okutаni 1984
: 10
, pl. 5,
figs. 10–14
, pl. 7,
figs. 1–11
.
Leptосhitоn
tоrishimensis
;
Sаito 1997
: 44
, pl. 1,
fig. 7
; 2001: 110; 2005: 103,
fig. 2
.
Type
material.
Holotype
(
UCM
No. 30966),
1 paratype
(
UCM
No.31840), and
3 paratypes
(
NMNS
No. 60006)
Type
locality.
Near Torishima Island
,
Japan
,
31°7.8’N
,
139°54.9’E
,
310 m
.
Material examined.
Taiwan
, Bashi Channel N/O
Fishery Researcher 1, “
TAIWAN
2000”, stn CP38,
21°32.1’N
,
120°48.1’E
,
1314–1317 m
, 9 spms, BL 4.0–7.0 mm,
01.08.2000
; NE coast of
Taiwan
, off Tashi, Fishing Boat
Chung Tung Long N26
, stn CP76,
24°56.5’N
,
122°01.5’E
,
115–170 m
, 3 spms, BL 4.5–8.0 mm, 0 7.05.2001.
Distribution.
Izu Islands,
310 m
(S.-
K. Wu & Okutani 1984
), Suruga Bay,
200–350 m
(
Saito 2001
), Tosa Bay,
177–220 m
(
Saito 2001
), Amami-Oshima
Island
,
288–311 m
(
Saito 2005
), and
Taiwan
,
170–1314 m
(this study). The species is reported from
Taiwan
waters for the first time and this find extends the distribution and depth range of this species considerably.
Remarks.
The specimens from
Taiwan
are similar to the specimens from Suruga Bay,
Japan
in their tegmentum sculpture (
Saito 1997
) and resemble specimens from Nansei Islands regarding the radula (
Saito 2005
) but it differs from the
type
specimens from Torishima Island,
Japan
by the absence of irregular radial rows of granules in lateral areas of intermediate valves and the postmucronal area of tail valve (
Wu & Okutani 1984
).
The disarticulated specimen from
Taiwan
(stn CP76, BL
8.2 mm
) has ten gills on each side extending from valve VI to anus and a radula that is
2.5 mm
long with 41 transverse rows of mature teeth. The girdle is covered by long scales (
43 x 18
µm) with 5–6 riblets and by scattered flattened needles (
90 x 17
µm) with 4–5 riblets on distal half. Marginal needles are similar to the dorsal ones. The ventral side of the girdle is clothed with long, smooth, pointed scales (
60 x 18
µm). Each suture has up to five smooth delicate needles. There are five aesthete pores in each granule on the tegmentum.