Pseudobranchiomma

Capa, María & Murray, Anna, 2015, A taxonomic guide to the fanworms (Sabellidae, Annelida) of Lizard Island, Great Barrier Reef, Australia, including new species and new records, Zootaxa 4019 (1), pp. 98-167 : 148-150

Pseudobranchiomma sp. 2

( Fig. 21 C–D)

Material examined. Queensland, Great Barrier Reef: AM W.41160, Reef 14-141, south of South Direction Island, 14°42′31′′S, 145°31′53′′E, coral rubble, 15 m, 26 Aug 2010; AM W.47333, North Direction Island, south deep reef slope, 14°45′04′′S, 145°30′45′′E, 6–28 m, 4 Sep 2010. Lizard Island: AM W.36978, MacGillivray Reef, deep reef slope, 14°39′25′′S, 145°28′22′′E, coral rubble, 30 m, 4 Sep 2010; AM W.43938, MI QLD 2360 (>25); AM W. 47698, MI QLD 2424.

Description of material examined. Specimens range from 3–18 mm long, 0.2–0.5 mm wide, with six or seven thoracic and numerous abdominal segments. Preserved specimens with radiolar crown with purple pigment in basal membrane, and four or five transverse irregular purple and orange bands along radioles ( Fig. 21 C–D). Posterior peristomial collar purple coloured. Body pale with small dark purple pigment spots sparsely distributed ( Fig. 21 C–D). Interramal eye spots distinct on thorax and abdomen ( Fig. 21 C–D). Radiolar crown with basal lobes slightly involuted ventrally; dorsal and ventral basal flanges absent. Basal membrane reduced. Radioles with serrated radiolar flanges; 3–6 serrations along radioles. Six rows of vacuolated cells supporting radioles basally, not extended into radiolar flanges. Radiolar eyes absent. Dorsal lips with medium length dorsal radiolar appendages; dorsal pinnular appendages absent. Ventral lips and parallel lamellae present, with prominent ventral sacs directed outside the branchial crown. Collar with dorsal margins separated by a wide gap, lateral margins smooth and large ventral lappets separated by a midventral incision. Glandular ridge absent on anterior chaetigers. Anterior thoracic ventral shields separated from adjacent tori by a gap, posterior thoracic shields in contact with tori; first ventral shield with m-shaped anterior margin. Interramal eyes conspicuous ( Fig. 21 C–D). Posterior peristomial ring collar with narrowly-hooded chaetae arranged in oblique rows. Following thoracic chaetigers with conical notopodia; superior thoracic chaetae elongate narrowly-hooded, inferior chaetae spine-like. Neuropodial uncini avicular, with three rows of teeth above main fang, well developed breast and short handle. Companion chaetae absent. Abdominal chaetigers with short conical neuropodia, with narrowly-hooded superior chaetae and spine-like inferior chaetae. Abdominal notopodial uncini similar to thoracic. Pygidium bilobed, with eyespots on both sides. Pygidial cirrus absent. Tube unknown.

Remarks. Pseudobranchiomma sp. 2 is characterised by 3–6 conspicuous serrations along its radiolar flanges, the absence of radiolar eyes and its colour pattern. This species belongs to Pseudobranchiomma "Group A" (according to Knight-Jones & Giangrande 2003) since it bears radiolar serrations distributed evenly along the entire length of the radioles, or at least for most of their length. This species resembles Pseudobranchiomma schizogenica Tovar-Hernández & Dean, 2014 , described from the Gulf of California, Eastern Pacific, in the colour pattern, the presence of serrated radiolar flanges along radioles, the absence of radiolar eyes, the shape of the collar — with lateral collar margins oblique and covering the anterior peristomial ring — and the conspicuous interramal eyespots. However, some observed differences include the number of serrations along the flanges, 3–6 in specimens described herein and 6–11 in P. schizogenica , as well as the shape of the radiolar serrations, step-like in the Australian specimens and circular in cross-section in P. schizogenica ( Tovar-Hernández & Dean 2014) . Moreover, this American species possesses a basal membrane as long as 1/4 of the radioles, while it is only incipient in the Australian congeners.

Habitat. Coral rubble, 6–30 m depth.

Distribution. Australia (Queensland: Lizard Island).

Figures

FIGURE 21. A – B. Pseudobranchiomma sp. 1, live specimen. A. Whole individual, ventral view, showing the bright colour pattern; B. Anterior end and radiolar crown, ventral view; C – D. Pseudobranchiomma sp. 2, preserved specimens; C. Radiolar crown and anterior thoracic chaetigers, lateral view; D. Detail of base of crown with diagonal collar and conspicuous interramal eyespots; E – G. Pseudopotamilla cf. reniformis. E. Live specimen, anterior end, lateral view; F. Same, dorsal view showing compound radiolar eye morphology and arrangement; G. Same, ventral view, showing the dorsoventral decrease in length of radioles.