Opisthosyllis mariae, Aguado, Teresa, Martín, Guillermo San & Ten, Harry A., 2008

Aguado, Teresa, Martín, Guillermo San & Ten, Harry A., 2008, Syllidae (Annelida: Polychaeta) from Indonesia collected by the Siboga (1899 – 1900) and Snellius II (1984) expeditions, Zootaxa 1673, pp. 1-48 : 18-20

Opisthosyllis mariae n. sp.

Fig. 7

Material examined. Holotype ZMA V.Pol. 1985.02, Indonesia, Sula Besi Isl., E coast, Sanana Bay, reef expl., 22 m, muddy bottom, Siboga Expedition, Sta. 193, 13/ 14 Sept. 1899; 1 paratype ZMA V.Pol. 2038.02, Indonesia, Maluku, Banda anchorage, trawl, dredge, reef expl., 9–45 m, black sand and coral, Siboga Expedition, Sta. 240, Nov. 22 Dec. 1899. (Both specimens as Syllis exilis ).

Comparative material examined. Opisthosyllis papillosa Hartmann-Schröder, 1960 . 4 Paratypes P- 14718- ZMH, Red Sea, Schab Anbar, Ghadarqa, Pocillopora , 1.5 m.

Opisthosyllis australis Augener, 1913 . 3 syntypes HZM V-7947, Western Australia, Shark Bay, 25°47’59.60’’S 113º40’32.53’’E; 1 syntype ZMB 53081, SW Australia, Freemantle, Rottnest, 31º59’29.85’’S 115º39’08.82’’E.

Opisthosyllis leslieharrisae . Holotype MNCN 16.01/10264 and paratypes MNCN 16.01/10265-66, USA, California, Santa Catalina Island, Wrighley Marine Science center, 33º26.7’N 118°29.1’W, 1– 4 m.

Description. Holotype 13.5 mm long, 1 mm wide, with 89 chaetigers. Paratype 22 mm long, 0.9 mm wide, with 84 chaetigers. Body circular, ventrally flattened; body width fairly constant, with tapering ends. Both specimens strongly pigmented red. Dorsal surface covered with spherical papillae distributed in two to three irregular transversal rows per segment ( Fig. 7 A). Papillae absent on parapodia. Prostomium wider than long, rectangular to oval, with two pairs of dark eyes, in trapezoidal arrangement; eye spots absent. Palps broad, fused at base, with distinct central groove; similar in length to prostomium, ventrally folded. Median antenna lost, insertion mark located medially on prostomium. Lateral antennae inserted on anterior margin of prostomium, with 10–12 articles. Occipital flap lacking. Peristomium shorter than subsequent segments ( Fig. 7 A). Dorsal tentacular cirri with 23–26 articles, ventral pair shorter, with 12–19 articles. Anterior dorsal cirri with 15–22 articles, midbody dorsal cirri alternating in length with 14–20 articles, longer ones inserted more dorsal and pointing up and shorter ones inserted more ventral and pointing down or laterally. Posterior dorsal cirri with 14–16 articles. Cirrophores well developed ( Fig. 7 I). Basal articles narrow, increasing in width and length in middle of cirri, becoming shorter and narrower distally ( Fig. 7 I). Ventral cirri conical, proximally inserted and not extending beyond parapodial tips. Pre- and postchaetal lobes present on all parapodia, the latter lobes longer than prechaetal on anterior parapodia, with one distal papilla; both lobes equal in length on posterior parapodia. Chaetal fascicle with three to four heterogomph compounds on anterior chaetigers, five to six on midbody and posteriorly. On anterior and middle parapodia, compound chaetae with unidentate blades with short spines on edge, distal part of shafts also with small spines ( Figs 7 B, D). Length of dorsalmost chaetal blades ca. 30 µm on anterior parapodia, and ca. 26 µm on median parapodia. On posterior chaetigers, compound chaetae with curved unidentate blades, smooth on margin (ca. 26 µm); shafts with two tips, distally curved ( Fig. 7 F). Dorsal and ventral simple chaetae not seen. Three aciculae in anterior parapodia protruding from parapodial lobes ( Fig. 7 C), three in median and posterior segments, one slightly curving at tip, all distally blunt ( Figs 7 E, G). Pygidium in both specimens regenerating; anal cirri absent ( Fig. 7 H). Pharynx shorter than proventricle, almost as broad as proventricle. Large conical tooth located in posterior part of pharynx. Proventricle long, rectangular, through segment 8 to 16, cell-rows difficult to distinguish ( Fig. 7 A). Paratype developing a stolon of 21–22 segments.

Remarks. Opisthosyllis mariae n. sp., is characterised by having a body surface covered by spherical papillae, unidentate blades from midbody to posterior end and posterior shafts distally curved. There are currently five other species described within Opisthosyllis with papillae over the dorsum, O. viridis Langerhans, 1879 ; O. australis Augener, 1913 ; O. papillosa Hartmann-Schröder, 1960 ; O. convexa Lee & Rho, 1994 and O. leslieharrisae Aguado, San Martín & Nygren, 2005 . Aguado et al. (2005) concluded that the type material of O. australis from ZMH did not exhibit any papillae. However, revision of types of the same species deposited in the ZMB reveal this character to be present, but papillae are badly preserved in the ZMH type. All five species have compound chaetae with clear bidentate blades, while blades in O. mariae are unidentate. In addition, O. viridis , O. papillosa , O. australis and O. convexa have conical papillae considerably smaller than the spherical ones of O. mariae . Opisthosyllis leslieharrisae has bigger papillae, present in two sizes ( Aguado et al., 2005). In addition, shafts of posterior chaetae in O. mariae are distally curved, with two tips. This combination of characters is not present in any other Opisthosyllis species as described by Augener (1913), Hartmann-Schröder (1960), Lee & Rho (1994), López & San Martín (1994) and in our observations. A table comparing species of Opisthosyllis is given in Aguado et al. (2005).

Distribution. Indonesia.

Etymology. This species is named after our colleague and good friend María Capa for her valuable contributions to the taxonomy of polychaetes and her inestimable friendship.

Figures

FIGURE 7. Opisthosyllis mariae n. sp. Holotype V. Pol. 1985.02. A: Anterior part, dorsal view; B: Anterior chaetae; C: Anterior aciculae; D: Midbody chaetae; E: Midbody aciculae; F: Posterior chaetae; G: Posterior aciculae; H: Posterior part, dorsal view; I: Midbody parapodium, posterior view. Scale A, H: 0.5 cm; B – G: 30 µm; I: 1 mm.