Exogone (Exogone) brevifalcigera Hartmann-Schröder, 1990

Guillermo San Martin, 2005, Exogoninae (Polychaeta: Syllidae) from Australia With the Description of a New Genus and Twenty-two New Species, Records of the Australian Museum 57, pp. 39-152 : 140

Exogone (Exogone) brevifalcigera Hartmann-Schröder, 1990

Fig. 88A–M

Exogone brevifalcigera Hartmann-Schröder, 1990: 56 , figs. 24–26 .

Material examined. AUSTRALIA: NEW SOUTH WALES. PARATYPES: 2 specimens, AM W203314, Angourie Point, Maclean, 29°21'S 154°22'E, 0 m, Hartmann-Schröder, 17 Jan 1976. 1 specimen, AM W26398, South Ledge, Cook Island, 28°11.65'S 153°34.63'E, rock, 15 m, K.B. Attwood, 9 Jun 1993. 1 specimen, AM W26399, Split Solitary Island, 30°15'S 153°11'E, 17 m.

Description. Body small, slender, relatively broad, 2.9 mm long, 0.4 mm wide, 38 chaetigers; holotype slightly longer, 3.2 mm long, 38 chaetigers. Prostomium rectangular to oval; 4 eyes in trapezoidal arrangement; anterior eyespots not seen. Antennae small, inserted close to each other, approximately on middle of prostomium; median antenna about twice as long as the lateral antennae, slightly pyriform, shorter than prostomium; lateral antenna ovoid, difficult to see ( Fig. 88A ). Palps broad, longer than prostomium, fused along their length, with a distinct dorsal furrow, and distal notch. Peristomium small, dorsally partially or totally covered by chaetiger 1; tentacular cirri minute, smaller than lateral antennae. Dorsal cirri ovoid, similar to lateral antennae but slightly longer, shorter than parapodial lobes, present on all segments ( Fig. 88A ). Parapodia each with 1 compound chaeta with short, slender, unidentate, smooth or nearly smooth, spiniger-like blade, spinose shafts slightly different on midbody and posterior segments ( Figs. 88C,G,K ); in addition 5 falcigers on anterior parapodia reduced to only 2 on posterior parapodia; falcigers with distally spinose shafts and minute, sometimes indistinct, smooth, bidentate blades with subdistal tooth longer than distal tooth ( Figs. 88E,H,L ), slightly longer on anterior parapodia, about 5 µm, than on posterior ones, 3 µm long. Dorsal simple chaetae from anterior parapodia, with rounded tips and finely spinulose subterminally, slender on anterior parapodia ( Fig. 88D ), thicker, unidentate, with less spines posteriorly ( Fig. 88F,J ). Ventral simple chaetae on posterior parapodia, sigmoid, unidentate, provided with short, small spines above ( Fig. 88M ). Acicula solitary, distally rounded ( Fig. 88I ). Pygidium semi-circular, with 2 long anal cirri ( Fig. 88B ). Pharynx through 4–5 segments; pharyngeal tooth conical, acute, long, longer than median antenna ( Fig. 88A ). Proventricle through 4–5 segments, with about 21 muscle cell rows.

Remarks. Exogone (E.) marisae Pascual, Núñez & San Martín, 1996, from Canary Islands have the falcigers similar, with short blades, encased in spinose shafts, but the antennae are inserted more anteriorly on the prostomium, the proventricle is shorter, and the dorsal simple chaetae have aristae ( Pascual et al., 1996).

Distribution. Australia (New South Wales).

Habitat. On shallow hard substrates.

Figures

Fig. 88. Exogone (Exogone) brevifalcigera. (A) anterior end, dorsal view.(B) posterior end, dorsal view.(C) spiniger-like chaetae, anterior parapodium. (D) dorsal simple chaeta, anterior parapodium. (E) compound falcigers, anterior parapodium. (F) dorsal simple chaeta, midbody.(G) spiniger-like chaeta, midbody. (H) compound falcigers, midbody. (I) acicula. (J) dorsal simple chaeta, posterior parapodium. (K) spiniger-like chaeta, posterior parapodium. (L) compound falcigers, posterior parapodium. (M) ventral simple chaeta. Scale A: 0.18 mm, B: 0.1 mm, C–M: 20 µm.

Fig. 24. Prosphaerosyllis magnoculata. (A) anterior end, dorsal view. (B) compound chaetae, anterior parapodium. (C) dorsal simple chaeta, anterior parapodium. (D) dorsal simple chaeta, posterior parapodium. (E) compound chaetae, posterior parapodium. (F) ventral simple chaeta, posterior parapodium. (G) acicula. Scale A: 0.1 mm, B–G: 20 µm.

Fig. 25. SEM of Prosphaerosyllis magnoculata. (A) dorsal view of a mature male with long natatory notochaetae. (B) prostomium, peristomium and chaetiger 1, laterodorsal view (antennae missing). (C) midbody segments, laterodorsal view. SEM of Prosphaerosyllis multipapillata. (D) dorsal view. (E) anterior end, dorsal view. (F) ventral view, midbody.

Fig. 26. Prosphaerosyllis papillosissima. (A) dorsal view of a mature female carrying eggs. (B) dorsal simple chaeta, anterior parapodium. (C) compound chaetae, anterior parapodium. (D) dorsal simple chaeta, posterior parapodium. (E) compound chaetae, posterior parapodium. (F) ventral simple chaeta. Scale A: 0.2 mm, B–G: 20 µm.