Sipuncula from Hainan Island (China) Author Acd text Journal of Natural History 2000 34 2187 2207 journal article 1464-5262 Aspidosiphon (Aspidosiphon) muelleri Diesing, 1851 Material. Sanya Bay , 22 March 1992 , one specimen ; Sanya Bay , 23 March 1992 , one specimen . Description. Trunk 7.5± 19 mm long and 1.3±2.5 mm wide. Introvert slightly longer than the trunk, 13±20 mm long. Anal shield with a dorsal zone of longitudinal ridges. Caudal shield with radial furrows. Papillae distributed over the entire trunk. Unidentate compressed hooks in 30±40 rings. Hooks 25±30 m m in height (®gure 8g , h). The proximal part of the introvert has scattered conical spines (®gure 8e, f). Two retractors have their origins near the caudal shield. Discussion. The continuous longitudinal musculature and the longitudinal grooves of the anal shield are diagnostic for the species. The morphology of the hooks of A. (A.) muelleri has always been a source of confusion. Cutler and Cutler (1989) concluded that each worm has the ability to produce either only unidentate hooks, only bidentate hooks, or some of both. In the specimens of the collection of Hainan , unidentate hooks are the only type that appear closely followed by conical spines. According to Cutler (1994) this species is the most widespread, eurytopic and polymorphic Aspidosiphon ; thus, comparable with Gol W ngia margaritacea (Sars, 1851), Phascolion strombus (Montagu, 1804) or Sipunculus nudus Linnaeus, 1766 , which are also species with a long list of junior synonyms and a morphology di cult 2014 to non-existent be de®ned in. It America can be. found It is frequent in all oceans in the and Western continents Paci®c, although Ocean, and it is has almost been February the the recorded ® South rst records from China the of Sea this Gulf (Li species of et Tonkin al. from, 1992 (Hainan Murina b). The, Island 1977 specimens)., Vietnam of the (Murina collection, 1989 represent), and 14 34 Subgenus Aspidosiphon (Paraspidosiphon) (Stephen, 1964) : 02 Aspidosiphon (Paraspidosiphon) steenstrupii Diesing, 1859 at ] Material. Dadonghai Bay , 29 March 1992 , one specimen ; Yezhu Island. Yalong Bath Bay , 19 March 1992 , one specimen ; Yezhu Island , South tip, 19 March 1992 , one specimen . of Description. Trunk 17±37 mm long and 2±4.5 mm wide. Introvert shorter than University the Anal grooves trunk shield. Papillae length ungrooved, 9 distributed ± 32 mm , with long calcium all. Whitish over carbonate the coloured entire spots trunk trunk.. Caudal Bidentate and brown shield hooks pre-anal with (50 radiating ± region 65 m m. [tall) arranged in several rings at the distal part of the introvert (®gure 9d). There by are scattered dark pyramidal hooks ( 40±50 m m tall) proximal to the rings (®gure 9c). Downloaded of oses internal Tubular hooks. Two clear papillae. Internally retractors streak (25., ± Longitudinal have 30 the m m bidentate their tall) origins (® musculature gure hooks 9 near a, exhibit b) the are in caudal interspersed bands a tongue-like shield with numerous. between Two extension nephridia both anastomon kinds the of about 80% the trunk length, are attached to the body wall by their anterior halves. Rectal caecum present. Discussion. The longitudinal musculature in bands, the fact that all compressed hooks are bidentate and arranged in rings, and the ungrooved anal shield are diagnostic characters for the identi®cation of this species. Furthermore, the presence of large tubular papillae over the introvert has been noticed in the specimens of this collection, which has provoked some doubts on whether they are true papillae or something more similar to conical hooks. The species inhabits coral rocks in shallow waters of tropical seas. It is distributed throughout the Indian Ocean, Western Paci®c Ocean and Hawaii, and in areas of the Caribbean sea and the Gulf of Guinea . In the area investigated it has previously been recorded from several localities in Indochina (Leroy, 1942), the Xisha Islands (Li, 1982), Vietnam (Murina, 1989) and the South China Sea (Li et al. , 1992b). However, it had not been previously recorded for Hainan Island. 2014 February 14 34: 02 at] Bath of University [by Downloaded FIG. 9. (a, b) Introvert tubuliform papillae from Aspidosiphon (Paraspidosiphon) steenstrupii Diesing, 1859 ; (c) introvert pyramidal hook from the same species; (d) introvert bidentate hook from the same species (scale5 25 m m); (e) introvert hook from Cloeosiphon aspergillus (de Quatrefages, 1865) (scale5 100 m m). Genus Cloeosiphon GruÈbe, 1868