Sabellastarte spectabilis (Grube, 1878)

Knight-Jones, Phyllis & Mackie, Andrew S. Y., 2003, A revision of Sabellastarte (Polychaeta: Sabellidae), Journal of Natural History 37 (19), pp. 2269-2301 : 2274-2278

Sabellastarte spectabilis (Grube, 1878)

(figure 2)

Sabella indica Savigny, 1822 , Indian Ocean, neotype ( MPW 374 a) [not Sabella indica Abildgaard, 1789 : Pectinariid]: Ehlers , 1897, in part, Zanzibar (ZMH PE 1343 ).

Sabella spectabilis Grube, 1878: 253 , lectotype from Masolac, Bohol Is. ( MPW 374 a crown attached to thorax, rest of body in two pieces) and five paralectotypes same location with detached crowns and fragmented bodies, one dried out ( MPW 374 ): Treadwell, 1920, Albatross Philippine Exp. 1907–1910, Stn a437 ( USNM 17510 ) ; Ehlers, 1920, Amboina, Molucca Is., Indonesia ( ZMH PE 1352 ) and Pulo Edam, Malayan Archipelago ( ZMH 1353 ) ; Fossa and Nilsen, 2000: 130,131).

Laonome spectabilis: Marenzeller, 1885: 213 , Cebu Is., Philippines ( NHMW 1961 ).

Sabella fusca: McIntosh, 1885: 492 , Ceylon (NHML 1874.10.2.3).

Sabellastarte indica: Fauvel, 1932 , Ye, Burma (MNHN A464); Mesnil and Fauvel, 1939, Siboga Expd., Ambon Recif (ZMA V. Pol. 1712). [Not Stn 115 (ZMA V. Pol. 1713) = Stylomma palmata Knight-Jones, 1997 ].

Sabellastarte sanctijosephi: Gibbs, 1969 , figure 137, 1971, Peleki Is., Solomon Is. (NHML 1970.823, 824, 825, 826); Bailey-Brock, 1976, Hawaii; George and George, 1979, figure 58:6.

Additional material. Mauritius, Pte aux Cannoniers (NHML 1950.3.3.1, two specimens, as Sabellastarte indica ), Lagoon, Pte du Tamarin (ZMA V. Pol. 2392 as S. magnifica ); Australia, Broome, WA (NRM UP1911 and NTM W.2206 both as S. indica ), Kimberley Coast, WA (NTM W.6776, 6769, 6791), Coburg Peninsula, NT (NTM W.33, W52), Darwin, NT (NTM W.56, 3843, 4229); Indonesia, Amboina (ZMH PE 1352) and Indonesian-Dutch Snellius II Exp.: Stn 4.005, Ambon, N coast between Hita and Hila (ZMA V. Pol. 4971), and SW Salaya, Stn 4169B (NNML 18526, as Sabellidae ); Philippines, Cebu Is. (ZMH V17659 as S. indica and ZMH V1790 as S. magnifica ); Japan, east Tokyo Bay (Uchiba), west coast of Boso Peninsula (Katsuura) and Okinawa, Zampa Cape (CMNH); Taiwan, Pitou (ASIZ.W 203, three specimens), Keelung, Wong-Hai Lane (ASIZ.W, three specimens), Penghu Islands, Watung (NMW.Z.2000.44.1, one specimen, coll. P.K.J.); Japan, east Tokyo Bay (Uchiba), west coast Boso Peninsula (Katsuura), Okinawa, Zampa Cape (CMNH); Hawaii, Oahu, Coconut Is. Harbour), Ala Wai Yacht Harbour, Waikiki (P.K.J.).

The following description is of the lectotype ( MPW 374 a); data in parentheses refer first to a specimen from Mauritius ( NHML 1950.3.3.1) and the second entry to the largest of two specimens collected at Waikiki , Hawaii. An equally large specimen was found in Ehlers’ material from Amboina, Indonesia ( ZMH PE 1352 ) .

Description. Body without crown about 80 (94, 142) mm long, 12 (12, 12.4) mm wide with about 165 (180, 160) segments, of which 10 (nine on left, eight on right, eight each side) are thoracic (figure 2A); crown about 33 (45, 63) mm long with short base (figure 2A), vestigial interradiolar web (figure 2B,C, length scarcely equalling length of one typical ventral shield) and small D-shaped flange on each dorsal margin near web; crown radioles 80 (69, 90) each side, many interdigitating, each without paired ridges along entire length (figure 2E, F, G), tips beyond pinnules fairly long, slightly tapered (figure 2H); dorsal lips long, about 19 mm, with midrib support, each shallowly webbed to adjacent radiole below pinnules (without pinnular support); thorax wider than long (figure 2A), first segment scarcely longer than following thoracic segments (viewed laterally and discounting height of collar, figure 2A); dorsal collar high, margins with deep notches above dorsal pockets each side of midline (figure 2B), lateral margins more or less transverse to axis of body and well above junction of crown and thorax (figure 2A); ventral collar forming two subtriangular lappets (figure 2C), not overlapping at midline when in forward position (figure 2D from paralectotype); first ventral shield somewhat longer than others in thorax, with straight anterior margin embayed medially, and with slight indication of transverse groove (figure 2D); all thoracic tori in contact with sides of ventral shields (figure 2C, D); thoracic uncini, like those of abdomen, each with crest of numerous fine teeth covering half of distal ‘head’, distance between end of shaft and breast a little shorter than distance between breast and crest; superior thoracic chaetae curved and slender (figure 2J), each inferior chaeta more geniculate, with knee scarcely wider than shaft (figure 1K), about 60 chaetae in each fascicle, with emergent parts (figure 2P) about as long as two or three thoracic shields; superior and inferior abdominal chaetae similar (cf. figure 2J, K and L, M); tube of hardened mucus, with (above substratum) outer layer of muco-silt.

Pigments mostly brown, with darker liver-brown areas on ventral shields, peristome and most of crown base and lower parts of radioles. Rest of crown light brown with one or more darker bands (five in largest specimen examined) crossing rachis and pinnules. Rest of body mid or dark brown with pale areas along edge of collar and uncinal ridges, axial stripes on dark crown base (in line with webbed region between radioles) and around abdominal parapodia. Dorsal thorax lighter brown with darker U-shaped lines level with base of each dorsal collar pocket. Dark brown subtriangles dorsal to thoracic fascicles, and ventral to abdominal fascicles (usually distinct); irregular blotches scattered across general surface absent; interramal spots discrete and often distinct.

Habitat. Sabellastarte spectabilis from Taiwan (Penghu Islands) was associated with small boulders in terrain that became a shallow lagoon at low water. Ambon material ( ZMA V. Pol. 4971) was found on a sandy reef flat with patches of boulders and rocks on gravel bottom at 1–6 m depth. Fairly small specimens from northern Australia were from similar terrain at low water spring tides. Material from the Philippines are particularly large, as are abundant specimens in Waikiki Marina and Coconut Is. Harbour. Sabellastarte spectabilis obviously does well in boulder areas or coral crevices above muddy substrata in shallow water .

Variation. The pigments of the type material are typical of populations of large specimens from Mauritius, Indonesia, Taiwan and Hawaii, but smaller specimens like that of Treadwell (1920) from the Philippines ( USNM 17510 , width 10 mm) have ventral shields, abdomen and most of thorax paler, against which the parapodial triangles, interramal spots and U-shaped marks on collar pockets appear to be more distinct. The crown base, peristome, collar and inter-uncinal ridges, however, are dark-coloured as usual. Irregular pigment flecks or blotches are absent from the general body surface. Some specimens show evidence of regeneration after damage. Specimens from Cebu in the Philippines had seven thoracic tori on the right, imperfectly engaging with just six adjacent ventral shields which were longer than usual. The emergent parts of the thoracic chaetae measured 2 mm, typical of widespread populations of S. spectabilis , but that was only the length of two thoracic shields in this specimen. The smallest of three specimens from Taiwan (Keelung) shows both thoracic and posterior regeneration .

Remarks. Marenzeller (1885) was the first to suggest that Laonome spectabilis (Grube) might be the same as Sabella indica Savigny , but he was mainly concerned with characters to show that his ‘ Laonome ’ (= Sabellastarte ) japonica was a valid new species (see below).

In spite of his comment ‘The number of thoracic segments is known to be subject to individual variations’, Willey (1905) gave the name Sabellastarte indica var. quinquevalens to some of his material from Sri Lanka, which had only five pairs of thoracic tori as opposed to the seven pairs in his other material, which he called S. indica! He also noted ‘It is likely that S. indica is co-specific with Grube’s S. spectabilis ... ’. Judging by his description of dark pigments and heavily interdigitated crown radioles, his material (not found in any museum) was almost certainly S. spectabilis .

Fauvel (1930) synonymized material of Sabellastarte indica with Sabella pottaei Quatrefages (1866, from New Caledonia), but S. pottaei is distinct from S. spectabilis , though the same as S. japonica (see below).

Distribution. Several Sabellastarte ‘ indica ’ holdings have proved to be misidentifications, even to genus. Material from Teneriffe (Johannson, 1927: 155) is Bispira mariae Lo Bianco, 1893 (see Knight-Jones and Perkins, 1998: 429), that from the Gulf of Guinea (Fauvel and Rullier, 1959) Station 52 is Branchiomma sp. whilst Station 126 is Bispira guinensis (Augener) (histolysized radioles and companion chaetae, respectively, were overlooked). Sabellastarte indica var. oculata Fauvel and Rullier (1959) from Cape Verde Is. is also a histolysized specimen of Branchiomma , as are two specimens from Île du Prince, Guinee (collected by M. Parfait, 1889, MNHNP A258 as S. indica ), perhaps B. nigromaculata (Baird) , judging from the numerous radioles, a few stylode remnants and a short, wide thorax. Branchiomma nigromaculata is common in the Caribbean, but also occurs in the Cape Verde Is. (P.K.J.). We have not been able to examine material from Senegal and Mauritania (Sourie, 1954; Fauvel, 1957; Fauvel and Rullier, 1957), but doubt whether it will turn out to be Sabellastarte spectabilis .

Sabellastarte spectabilis is found with S. pectoralis in Mauritius, Zanzibar and Hawaii, with S. japonica in Northern Territory ( Australia) and Japan. They may well occur together in Taiwan as S. japonica has been identified from Xiamen (Amoy) across the Taiwan Straits (see below).

Sabellastarte spectabilis is probably confined to the Indo-Pacific Oceans. Our studies so far include records from Zanzibar, Mauritius, Sri Lanka, Burma, Indonesia, Western Australia and Northern Territory ( Australia), Philippines, Japan, Taiwan and Hawaii.