Brania pusilla (Dujardin, 1839)

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 : 102-103

Brania pusilla (Dujardin, 1839)

Fig. 57A–E

Exogone pusilla Dujardin, 1839: 298 , Figs. 9, 10.

Grubea pusilla .–Fauvel, 1923: 299, fig. 115, a–f.

Brania pusilla .–Day, 1967: 267, fig. 129d–f. Campoy, 1982: 248, pl. 14. Hartmann-Schröder, 1971: 163; 1982: 68, figs. 51, 52; 1984: 22; 1986: 42; 1987: 39; 1989: 28; 1996: 169, fig. 72. Gardiner, 1976: 130, fig. 10o. San Martín, 1984a: 181, pl. 38; 2003: 151, figs. 73, 74.

Grubea pusilloides .–Haswell, 1920a: 222, pl. 17, figs. 27–29.

Brania pusilloides .–Day & Hutchings, 1979: 100.

Material examined. AUSTRALIA: NEW SOUTH WALES. SYNTYPES of Grubea pusilloides, 2 specimens, AM W478, Port Jackson, 33°51'S 151°16'E. Collected & identified by Haswell. 1 specimen on slide, AM W25236, Port Jackson, 33°50'S 151°16'E. Collected & identified by Haswell. 1 specimen on slide, AM W25237. Identified by Haswell. 1 specimen on slide, AM W25238. Identified by Haswell. 1 specimen on slide, AM W8632. Identified by Haswell.

Description. Body small, short, about 2 mm long, 0.13 mm wide, for 27 chaetigers. The longest specimen examined (W2537) is 1.65 mm long, with 26 chaetigers. Prostomium semi-circular, with 4 eyes in trapezoidal arrangement. Antennae elongate, spindle-shaped to bowling-pin shaped; median antenna longer than lateral ones, similar in length to prostomium and palps together, inserted between posterior eyes; lateral antennae slightly longer than prostomium, inserted in front of and slightly medial to anterior eyes, similar in shape to median antenna. Palps similar in length to prostomium, fused on their basal 2 ⁄ 3 (Fig. 57A). Peristomium similar in length to following segments; dorsal tentacular cirri similar to lateral antennae but slightly shorter and distally slightly truncated, ventral tentacular cirri similar to dorsal ones but shorter. Dorsal cirri subrectangular, distally truncated, oval in shape, containing fibrillar material (Fig. 57A), slightly longer than parapodial lobes. Ventral cirri digitiform, shorter than parapodial lobes. Compound chaetae similar throughout, slightly shorter on anterior parapodia, with heterogomph articulation, provided with short subdistal spines on shafts; blades unidentate, distally rounded, slightly hooked, and short marginal spines and a subdistal spine near tip, longer than other spines, more marked on longer blades (Fig. 57E). Parapodium each with 6–8 compound chaetae on anterior parapodia, 3–4 on posterior parapodia; strong dorsoventral gradation in length of blades; on each parapodium 1–2 compound chaetae with long blades, about 28 µm long, and remaining chaetae with shorter blades, posteriorly diminishing progressively in length, 16–17 µm above, 10 µm below. Dorsal simple chaetae from anterior parapodia, bidentate, provided with short marginal spines (Fig. 57B). Ventral simple chaetae on each posterior parapodia, sigmoid, smooth and unidentate (Fig. 57C). Solitary acicula on each parapodium, tip enlarged and rounded, slightly hollow (Fig. 57D). Pharynx longer than proventricle, through 4 segments; pharyngeal tooth conical, located near opening (Fig. 57A). Proventricle short, through 2 segments, with about 15–16 muscle cell rows. Pygidium small, bilobed, with two long anal cirri, similar in length to median antenna. Attached juveniles lacking eyes, dorsal cirri on chaetiger 2 and dorsal tentacular cirri.

Remarks. The Australian specimens were originally described as Grubea pusilloides and was considered as a different species than Brania pusilla from the European coasts; I have not found, however, any difference between the Australian and European specimens, so I consider both as synonyms.

Distribution. East Atlantic Ocean, from the North Sea to South Africa, extending to the Indian coasts of South Africa. West Atlantic (North Carolina). Mediterranean Sea. Australia (Western Australia, South Australia, Victoria, New South Wales).

Habitat. Found on all hard substrates, seagrasses, algae, calcareous concretions, also in coarse to fine sand, from intertidal to about 200 m depth, rare in waters deeper than 40 m.