Peanut worms of the phylum Sipuncula from the Nha Trang Bay (South China Sea) with a key to species
Author
Adrianov, Andrey V.
Author
Maiorova, Anastassya S.
text
Zootaxa
2012
3166
41
58
journal article
45619
10.5281/zenodo.279772
32627594-388c-40b3-8481-0b241b850847
1175-5326
279772
Aspidosiphon
.
elegans
(Chamisso & Eysenhardt, 1821)
(
Fig. 5 A–C
)
Material.
NhaTrang Bay: Mot Island,
7 m
depth, coral rubble,
8 specimens
; Tre
Island
,
6 m
depth, coral rubble,
11 specimens
; Tre
Island
, intertidal, fouling community,
7 specimens
; Mung Island,
12 m
depth, coral rubble,
6 specimens
; Nok Island,
5 m
depth, coral rubble,
2 specimens
; Diamond Bay, intertidal, coral rubble,
230 specimens
.
Description.
Trunk
10–30 mm
long, 2–2.5 mm wide, pale, semitransparent, with minute papillae; introvert subequal in length to the trunk length. Anal shield yellow-brown, with dark brown units, ungrooved; caudal shield weakly developed, yellow-brown. Tentacular apparatus with dorsal arc of 5–7 short tentacles around the dorsal nuchal organ. Bidentate compressed hooks arranged in rings in the distal introvert; dark conical hooks are scattered proximally. Continuous longitudinal musculature layer splits in the anal shield area; two retractor muscles originate at 5–10% of trunk length from caudal shield. Gut with 15–20 loops; spindle muscle attached posteriorly. Nephridia 75–80% of trunk length; attached to body wall for 80–90% of their length.
Discussion.
The species differs significantly from other representatives of the subgenus
Aspidosiphon (Aspidosiphon)
by two
types
of hooks, bidentate compressed and conical, and the anal shield structure.
Aspidosiphon elegans
is a tropical and subtropical species widely collected in the Atlantic, Indian and Pacific Oceans. In the West Pacific it has been found from
Australia
to
Japan
, while in the South
China
Sea it is only known from
Vietnam
and the Hainan Island. Usually it inhabits dead corals and soft rocks in intertidal and shallow waters.