Syllis cambuk, Martínez & Martín, 2020

Martínez, María José & Martín, Guillermo San, 2020, Syllidae (Annelida) from East Timor and the Philippines (Pacific Ocean), with the description of three new species of Syllis Savigny in Lamarck, 1818, Zootaxa 4834 (2), pp. 231-263 : 239-242

Syllis cambuk n. sp.

Figures 3 , 4

LSID: urn:lsid:zoobank.org:act:4DBC05AD-F447-48F9-8B44-5D10019174BB

Syllis sp. 1 Aguado et al., 2008: 39 , fig. 19.

Material examined. EAST TIMOR. East of Metinaro, Secret Garden reef, 08°29’15”S 125°49’53” E, coral rubble, 19–21 m depth, 22 Sep 2012, coll. L.E. Hughes, holotype ( AM W.45801). East of Dili, south side off Christu Rei beach, coral slope, 08°31’46”S 125°36’21” E, dead coral rubble, 5–10 m depth, 23 Sep 2012, coll. L.E. Hughes, 3 paratypes ( AM W.53023), one of them used for SEM .

Description. Holotype, largest complete specimen, 30 mm long, 1 mm wide, with 94 chaetigers. Body elongated, relatively large ( Fig. 3 A–C), without colour pattern; short and wide anterior segments ( Figs 3A , 4A, C ), becoming longer posteriorly ( Figs 3B , 4D ). Prostomium semicircular ( Figs 3A , 4A ), with four red eyes almost arranged in a straight line ( Fig. 3A ); eyespots not visible. Palps broad, elongated, longer than prostomium ( Fig. 3A ), sometimes bent downwards ( Fig. 4A ). Median antenna on middle of prostomium, between eyes, as longer than twice length of prostomium and palps together, with 40 articles ( Fig. 3A ); lateral antennae shorter than median one, half or a third as long as median antenna, with 24–30 articles, inserted near anterior margin of prostomium ( Figs 3A , 4A ). Nuchal organs ciliated, between prostomium and peristomium ( Fig. 4A , arrows, B). Peristomium wider than subsequent segments, covering posterior part of prostomium ( Fig. 4A ); dorsal tentacular cirri similar in length to median antenna, with about 40 articles ( Fig. 3A ); ventral tentacular cirri shorter than lateral antennae, with 15–16 articles ( Fig. 3A ). Dorsal cirri long, thin, pointed, whip-shaped, with numerous small articles ( Figs 3 A–C, 4A, C, D), typically alternating lengths: first pair longest, second shorter (similar to median antenna), third and fourth long (shorter than first), fifth short, sixth and seventh long, alternating long (with 40–41 articles) and short (29–30 articles, about one third shorter than long ones) from proventricular level backwards. Parapodial lobes conical, with two distinct lobes, anterior one digitiform, posterior one rounded, shorter than anterior one ( Fig. 4E ). Ventral cirri, thin, digitiform, shorter than parapodial lobes. Compound chaetae heterogomph falcigers, with relatively short blades, except in anterior-most parapodia ( Figs 3D , 4E, F ), bidentate, with straight, moderately long marginal spines, slightly longer distally and shorter basally. Anterior compound chaetae with proximal tooth robust, similar in length to distal one, both teeth close to each other ( Figs 3D , 4F ); from midbody backwards, compound chaetae with both teeth similar in shape, blunt, proximal one slightly longer than distal one ( Figs 3E , 4G ); more marked on most posterior chaetae ( Figs 3F , 4H ). Anterior parapodia with 10–12 compound chaetae, blades with marked dorso-ventral gradation, 44 µm dorsally, 28 µm ventrally; midbody parapodia with 8–10 compound chaetae, blades shorter and wider than those of anterior parapodia, 26 µm long dorsally, 23 µm ventrally; posterior parapodia each with 7–8 compound chaetae, similar to those of midbody parapodia; blades 32 µm dorsally, 23 µm ventrally. Dorsal simple capillary chaetae not seen. Ventral simple capillary chaetae on most posterior parapodia, with two similar distal teeth, sharpened ( Fig. 3J ). Anterior parapodia with four aciculae, three with blunt tips and one distally acute ( Fig. 3G ); midbody parapodia with two aciculae, distally blunt ( Fig. 3H ); posterior parapodia with solitary, distally pointed acicula ( Fig. 3I ), slightly protruding out from parapodial lobes ( Fig. 4H ). Pharynx long, extending along eight segments; elongated, conical, acute pharyngeal tooth, on anterior pharyngeal margin ( Fig. 3A ). Proventricle somewhat shorter and wider than pharynx, extending along six segments ( Fig. 3A ), with about 32 muscle cell rows. Pygidium short, with two long anal cirri with about 33 articles ( Fig. 3C ).

Remarks. This species is characterized by its large size body and having anterior segments much wider and shorter than posterior ones, long whip-shaped dorsal cirri composed of numerous small articles and bidentate midbody and posterior chaetae with both teeth equal in size and shape, broad, close to each other and with marginal spines very short at the base, progressively longer towards the tip of the blade, reaching the end of the proximal tooth. Our specimens correspond closely to the species described as Syllis sp. 1 from Indonesia by Aguado et al. (2008) which, together with the geographical proximity, lead us to consider them as the same species. Syllis sp. 1 is strongly dark-red-pigmented and S. cambuk . n. sp. did not present any colouration, although any possible colouration could have been lost during material processing or storage in 70% alcohol. Syllis villenai Aguado, San Martín & ten Hove, 2008 from Indonesia shares some features (i.e., long whip-shaped dorsal cirri, shape of chaetae), but has blades with much longer marginal spines. Syllis tigrinoides Augener, 1924 from Florida and the Caribbean West Indies coincide in body shape, long cirri, two parapodial lobes and shape of chaetae and aciculae, and differs in having posterior compound chaetae with very thickened shafts and an angled inner edge, and very thick aciculae, protruding from the parapodial lobes much more than in our new species ( Uebelacker 1982, 1984). Syllis tigrinoides was considered as a synonym of Syllis corallicola Verrill, 1900 , and was later re-erected by San Martín (1992, 2003). Dentatisyllis uebelackerae Ding, Licher & Westheide, 1998 , from the Gulf of México, also has chaetae and aciculae similar to S. cambuk n. sp., but the marginal spines of the blades of compound chaetae are slightly longer and, above all, has the pharyngeal crown of denticulations, characteristic of this genus ( Perkins 1981; Ding et al. 1998), which was not present in the species from East Timor.

Etymology. The specific name refers to the shape of its dorsal cirri ( cambuk is an Indonesian word for “whip”). East Timor is one of the two independent states that constitute the island of Timor, where Indonesian, among other languages, is spoken. Therefore, it seemed appropriate that the etymology of this new species described had a meaning in Indonesian.

Habitat. Dead coral rubble, 5 to 21 m depth.

Distribution. Only known from the type locality at East Timor.

Figures

FIGURE 3. Syllis cambuk n. sp. Holotype (AM W.45801), drawn from preserved specimen. A) anterior end, dorsal view. B) midbody segments, dorsal view. C) pygidium and anal cirri, dorsal view. D) compound chaetae, anterior parapodium. E) compound chaetae, midbody parapodium. F) compound chaetae, posterior parapodium. G) aciculae, anterior parapodium. H) aciculae midbody parapodium. I) acicula, posterior parapodium. J) ventral simple chaeta. Scale bars: 20µm.

FIGURE 4. Syllis cambuk n. sp. Paratype (AM W.53023). Scanning Electron Micrographs.A) prostomium, dorsal view. Nuchal organs indicated by arrows. B) detail of nuchal organ. C) anterior segments, dorsal view. D) midbody segments, dorsal view. E) anterior parapodia, dorsal view. F) compound chaetae, anterior parapodium. G) compound chaetae, midbody parapodium. H) compound chaetae, posterior parapodium.