Glomerula piloseta ( Perkins, 1991 )

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 : 119-121

Glomerula piloseta ( Perkins, 1991)

( Fig. 8 )

Calcisabella piloseta Perkins, 1991: 262 –266, fig. 1–3. Glomerula piloseta .— Vinn et al. 2008: 295.

Material examined. Queensland, Lizard Island: Holotype: AM W.20111, lagoon near entrance, sheltered side of reef, 15 m, 14°40′S, 145°28′E, 3 Mar 1986. Paratypes: AM W.20112 (>10, 1 on SEM), same collection details.

Description of material examined. No pigmentation in preserved specimens. Thorax with 11–15 chaetigers, abdomen with 9–12. Radiolar crown with semicircular lobes, each with five radioles. Dorsal and ventral flanges absent. Basal membrane incipient, narrow radiolar flanges present on proximal quarter of radioles ( Fig. 8 A). Four rows of vacuolated cells supporting radioles basally. Radiolar eyes absent. Dorsal lips rounded, without radiolar or pinnular appendages. Ventral radiolar appendages and parallel lamellae present; ventral sacs absent. Posterior peristomial ring collar with wide middorsal gap, midventral incision separating long and pointed ventral lappets ( Fig. 8 A). Glandular ridge on chaetiger 2 absent ( Fig. 8 A). Thoracic ventral shields in contact with adjacent neuropodial tori ( Fig. 8 A). Interramal eyespots absent. Collar chaetae narrowly-hooded in superior row and broadly-hooded in inferior row. Following thoracic chaetigers with conical notopodia; superior thoracic notochaetae narrowly-hooded, inferior thoracic notochaetae broadly-hooded; hoods with rough surface formed by numerous fibrous ends of long microtubules that compose the hood structure. ( Fig. 8 C). Thoracic neuropodia with uncini avicular with several rows of progressively shorter teeth above main fang, over most of its length ( Fig. 8 D), developed breast and handle absent. One to two companion chaetae per neuropodial torus, beginning on chaetiger 4, superior to dorsalmost uncinus ( Fig. 8 B) an autapomorphy for the species; companion chaeta with a nearly symmetrical hood and smooth surface ( Fig. 8 E–F). Abdominal neuropodia slightly elevated ( Fig. 8 G) with chaetae narrowly-hooded, with hood composed of long fibres ( Fig. 8 G–H). Abdominal uncini, from anterior and posterior chaetigers similar to thoracic ( Fig. 8 I–J). Pygidium bilobed, without pygidial cirrus ( Fig. 8 K). Pygidial eyes absent. Calcareous tube, circular in cross section, coiled, plain, attached to substrate or to other tubes, and sometimes with erect anterior end.

Remarks. This species is the only extant species in the genus. It is characterised and distinguished from other sabellids by the calcareous tube and chaetae with hoods formed by loose microtubules with plumose appearence, which explains why they have been referred to as spinose chaetae in the original description ( Perkins 1991). The companion chaetae were described as hooked, probably because the ones observed by Perkins (1991) were folded (as in Fig. 8 E), but are now shown to be paleate chaetae with almost symmetrical edges ( Fig. 8 F). Subsequent to its original description, some specimens were collected from Lizard Island in 2005, in order to provide genetic data of the species for deposition in GenBank ( Kupriyanova & Rouse 2008). Only known from the type locality.

Habitat. Sheltered zones of reef, under boulders in lagoon, 2–20 m depth.

Type locality. Lizard Island.

Distribution. Australia (Queensland: Lizard Island).

Figures

FIGURE 8. Glomerula pilosetosa, scanning electron micrographs. A. Anterior thoracic chaetigers and collar, ventral view; B. Neuropodial chaetigers 2 – 4 with single companion chaetae in chaetigers 3 and 4 (arrows); C. Anterior thoracic notochaetae, superior narrowly-hooded, inferior broadly-hooded; D. Anterior thoracic uncini with several rows of progressively shorter teeth above main fang, over most of its length; E. Companion chaetae, bent; F. Same, erect; G. Anterior abdominal chaetae narrowlyhooded; H. Posterior abdominal chaetae; I. Anterior abdominal uncini with several rows of progressively shorter teeth above main fang, over most of its length; J. Uncini from posterior chaetigers; K. Bilobed pygidium, lateral view.