Three New Shallow Species of Taeniogyrus and Rowedota (Echinodermata: Holothuroidea: Apodida: Chiridotidae: Taeniogyrinae) from Southern Japan
Author
Yamana, Yusuke
Wakayama Prefectural Museum of Natural History, Funo 370 - 1, Kainan, Wakayama 642 - 0001, Japan E-mail: yamanamako @ gmail. com & Corresponding author
yamanamako@gmail.com
Author
Tanaka, Hayato
Research Center for Marine Education, Graduate School of Science, The University of Tokyo, Hongo 7 - 3 - 1, Bunkyo-ku, Tokyo 113 - 0033, Japan
Author
Nakachi, Shu
Kuroshio Biological Research Foundation, 560 Nishidomari, Otsuki, Kochi 788 - 0333, Japan
text
Species Diversity
2017
2017-05-25
22
1
53
68
http://dx.doi.org/10.12782/sd.22_53
journal article
7118
10.12782/sd.22_53
92b7b550-4d8a-41e5-a00a-788a742e31c0
2189-7301
4585067
83A1A483-8D0E-4B0B-8C2B-0AF8B6D32A96
Rowedota chippiru
sp. nov.
(
Figs 1B
,
2B
,
3B
,
4B
,
5B
,
7
)
Material examined.
Holotype
: WMNH-2015-INV- 1476 (
ARA
,
14 September 2015
) (length
10.8 mm
, width
0.8 mm
)
.
Paratypes
: WMNH-2015-INV-1477 (
ARA
,
14 September 2015
) (length
6.3 mm
, width
0.5 mm
); WMNH- 2015-INV-1478 (
ARA
,
14 September 2015
) (length
3.6 mm
, width
0.4 mm
); WMNH-2015-INV-1479 (
ARA
,
14 September 2015
) (length
9.2 mm
, width
0.7 mm
); WMNH- 2015-INV-1480 (
ARA
,
14 September 2015
) (length
6.6 mm
, width
0.6 mm
).
Fig. 1. Lateral views of
Taeniogyrus mijim
sp. nov.
(holotype, WMNH-2015-INV-1457) (A);
Rowedota chippiru
sp. nov.
(holotype, WMNH-2015-INV-1476) (B); and
R. motoshimaensis
sp. nov.
(holotype, WMNH-2015-INV-1767) (C). Abbreviations: ad, anterior dorsal; av, anterior ventral; pd, posterior dorsal; pv, posterior ventral; te, tentacle.
Description.
Body small, anaesthetized length of largest specimen (WMNH-2015-INV-1476)
10.8 mm
(aπer preservation), cylindrical, slightly tapered toward posterior end (
Fig. 1B
,
Table 1
). Body colour (in preserved and living specimens) transparent white to greyish-pink. Mouth anterior; anus posterior. Oral disc inclined toward ventral side.
Ten tentacles non-retractile, slender, with bumpy skin. Each tentacle with one pair of digits; sensory cups absent (
Fig. 2B
). Colour of tentacles white to pink (in preserved specimens). Calcareous ring composed of five radial and five inter-radial plates, these all broad with distally flattened ginglymus ends (
Fig. 3B
). Polian vesicle single (
Table 1
). Stone canal undiscovered. Two long and unbranched tubules of ovaries; testis not observed. One ambiguous row of ciliated funnels situated in inter-radius of middle to posterior body cavity, near right side of mid-ventral longitudinal muscle.
Body wall containing wheel, sigmoid-hook, and thick-rod ossicles (
Figs 4B
,
5B
,
7
,
Table 2
). Wheel ossicles roundedhexagonal with six spokes. Inner margin of rim not parallel to outer margin, and rim narrower at corners. Teeth blunt, trapezoidal, 7–15 per radiant (means of
9–12 in
different specimens), discontinuous at slight concavities of rim at corners. Spokes not broad, their breadth amounting to 11–21% of diameter (means 11–19%) (
Fig. 7
). Wheel ossicles scattered sparsely in ventral inter-radial body wall but clearly arranged in longitudinal row in anterior ventral region. Wheel ossicle aggregations (wheel papillae) absent. Wheel ossicle diameter varying widely even in same tissue sample:
44–109 µm
(means
61–79 µm
) in anterior dorsal side,
49–88µm
(means
59–83 µm
) in anterior ventral side,
45–86 µm
(means
54–66 µm
) in posterior dorsal side, and
46–87 µm
(means
54–60 µm
) in posterior ventral side. Wheel ossicle diameter in anterior dorsal side significantly different among five specimens (Kruskal-Wallis test,
P
<0.05) but not in other body wall parts among three fully checked specimens (
Table 2
). In two of latter specimens (WMNH-2015-INV-1477, -1479), wheel ossicle diameter significantly different among four body parts (
Kruskal-Wallis
test,
P
s<0.05), but not in third specimen (WMNH- 2015-INV-1480).
Fig. 2. Three leπ-side tentacles of
Taeniogyrus mijim
sp. nov.
(holotype, WMNH-2015-INV-1457) (A);
Rowedota chippiru
sp. nov.
(paratype, WMNH-2015-INV-1480) (B); and
R. motoshimaensis
sp. nov.
(holotype, WMNH-2015-INV-1767) (C); all viewed from right side with dorsal side above.
Sigmoid-hook ossicles thick and large, arranged in single rows in inter-radii along both sides of longitudinal muscles, with pointed end facing toward inter-radius and blunt end facing toward longitudinal muscles. Outer edge of bend with 2–5 minute teeth. Shank broadest at bend, suddenly narrower distal to bend. Shank length
71–110 µm
(means
75–101 µm
) in anterior dorsal side,
71–100 µm
(means
76–92 µm
) in anterior ventral side,
57–81 µm
(means
66–77 µm
) in posterior dorsal side, and
51–77 µm
(means
55–72 µm
) in posterior ventral side. Shank length significantly different among five specimens in anterior dorsal part and among three specimens in other parts (Kruskal-Wallis test,
P
s<0.05) (
Table 2
). Shank length significantly different among four body parts in two fully checked specimens (WMNH-2015-INV-1477, -1479) (Kruskal-Wallis test,
P
s<0.05), but not in other one (WMNH-2015-INV-1480).
Thick-rod ossicles arc-shaped, distally blunt, with approximately 10–40 minute verrucae, arranged between wheel ossicles and sigmoid-hook ossicles. Length of thick-rod ossicles
64–79 µm
(means of
68–73 µm
in different specimens) in anterior dorsal side,
55–79 µm
(means
63–71 µm
) in anterior ventral side,
51–57 µm
(means
52–55 µm
) in posterior dorsal side, and
47–59 µm
(means
50–54 µm
) in posterior ventral side. Length of thick-rod ossicles in anterior ventral side significantly different among three specimens (
Kruskal-Wallis
test,
P
<0.05) but not those of anterior dorsal side among five specimens and posterior ventral side among three specimens (
Table 2
); posterior dorsal side not analysed statistically as thick-rod ossicles very rare. Length of thick-rod ossicles in two fully checked specimens (WMNH- 2015-INV-1479, -1480) significantly different among four body wall parts (Kruskal-Wallis test,
P
s<0.01) (
Table 2
); other fully checked specimen (WMNH-2015-INV-1477) not analysed due to its near lack of thick-rod ossicles in posterior dorsal side.
Tentacles containing rod ossicles (
Figs 5B
,
7
,
Table 3
), these spinous with low number of branches, length
41–78 µm
, means
51–68 µm
in five specimens, significantly different among them (Kruskal-Wallis test,
P
<0.01) (
Table 3
).
Distribution.
In sand in lower intertidal zone of calm beach, Araha Beach,
Okinawa Prefecture
, southern
Japan
.
Etymology.
The specific name
chippiru
, a noun in apposition, is derived from a Ryukyuan word for “something that is small”.
DNA barcode sequence.
A 650bp sequence of the mitochondrial
CO1
gene was obtained from a
paratype
specimen (WMNH-2015-INV-1479, GenBank accession number
LC152967
)
. Base frequency was A=16.3%, C=14.2%, G=24.2%, T=45.4%.