Galeolaria caespitosa Lamarck, 1818

Pillai, Gottfried, 2009, A revision of the genera Galeolaria and Pyrgopolon (Polychaeta: Serpulidae), with discussions on opercular insertion as a character in their taxonomy and relationships, and their zoogeography, Zootaxa 2060, pp. 47-58 : 48-50

Galeolaria caespitosa Lamarck, 1818

( Fig.1 A–F )

Galeolaria caespitosa Lamarck, 1818 : Mørch 1863: 367 –368, pl. 11, figs. 1–2. Dew 1959: 35, fig. 11 B–G, includes synonymies. Straughan 1967: 236; Hutchings 1982: 291, fig. 6.27 C.

Vermilia caespitosa Quatrefages, 1865 : Haswell (1884:17, pl. 31, fig. 5, pl. 32, fig. 1).

Material examined: 11 specimens, BM (NH) 1959.10.19.9/19, Port Hacking, New South Wales, Australia, collected and presented by B. Dew.

Description. Measurements: Tubes attain lengths of 2–3 cm (see also Hutchings 1982: 291). Of the worms examined, one, 18.5 mm long and of thoracic width 2.0 mm, has 41 branchial radioles on the left side and 38 on the right, arranged in 2 whorls on each side. Another, 17.0 mm long, has 80 abdominal segments, 30 radioles on the left and 31 on the right, arranged in one and a half whorls on each side. However, in the smallest specimens, 2.2–3.0 mm long, having about 20–24 abdominal segments, there are 4–6 radioles arranged in a circle on each side.

Tubes: White, occur in small to large clusters, often mutually bonded together and twisted amongst themselves, hence not easy to separate individual tubes without damage to ridges; more or less trapezoidal in cross-section, with forwardly directed transverse ridges/thickenings, which may or may not be welldeveloped; and a tongue- shaped process often projecting over the aperture. Longitudinal ridges may or may not be well developed; usually consist of two, with a longitudinal groove between them along the crest of the tube; sometimes only one longitudinal ridge may be well developed. See also Dew (1959: 35, fig. 11 A). This species contributes to reef building.

Worm: Operculum inserted mid-dorsally, well-distanced posteriorly and independently of branchial radioles of both sides, ( Fig. 1B ); peduncle winged; its opercular disc bears 3 or 4 calcareous basal plates anteriorly and, apparently, a single basal plate posteriorly, the latter surmounted by a group of 9–11 movable calcareous spines (see also Hutchings, 1982: 291). The Port Hacking specimen figured ( Fig. 1E–F ) has four basal plates, the two lateral ones being triangular while the two in between are elongated and somewhat rectangular, all occupying more than half the anterior part of the disc (see also Mørch 1863: plate XI, fig. 2, for an illustration of the basal plates of this species). The movable calcareous spines are located posteriorly on the operculum ( Figs. 1 E–F ), see also Mørch (1863: plate XI fig.1). They consist of a smooth, somewhat tapering, forwardly directed central spine, which is circular in cross-section, arising from a circular to oval calcareous base, and nine thick, flattened lateral spines, occurring asymmetrically, with five of them on the left and four on the right. The lateral spines are curved antero-laterally, and bluntly serrated along their postero-lateral edges ( Fig. 1F ). A ring of short rod-shaped calcareous processes, supported in a translucent rim, occurs along the edge of the opercular disc ( Fig. 1C–F ).

Three remarkable and hitherto unreported autapomorphies occur in G. caespitosa in relation to the faecal groove, the function of which is to channel faecal matter from the posterior end of the abdomen to the anterior end of the worm to be discharged outside the tube. In sabellids as well as in other serpulimorph polychaetes it takes a usually a well-defined mid-ventral course, from the posterior of the abdomen to its anterior end, and as it approaches the thorax it veers laterally and towards its dorsal side and continues along a less-defined course dorsally along the thorax towards its anterior region ( Knight-Jones & Fordy 1979: 122). Quite interestingly, however, instead of veering past the opercular peduncle as in other serpulimorphs, the faecal groove in G. caespitosa , continues mid-dorsally along the opercular peduncle ( Figs. 1C–D )! The second autapomorphy relates to a pair of sensory papillae, occurring one on either side at the anterior end of the longitudinal peduncular faecal groove. The third concerns the calcareous mid-dorsal process of the palisade constituting the opercular rim. It is considerably larger and broader than the rest and curved outwards, evidently related to deflecting the faeces-bearing stream arriving along the opercular faecal groove outwards and away from the radiolar crown, rather than anteriorly towards it ( Fig. 1C–D ).

Thoracic membranes extend to the end of the thorax. Apron: present ( Fig. 1A ).

C haetae: Special collar chaetae: simple. Thoracic uncini bear nine teeth; their anterior tooth gouged, serrated. Posterior abdominal uncini rasp-shaped; their anterior tooth gouged, serrated. Abdominal neurochaetae geniculate, possess long shafts projecting conspicuously beyond the body wall ( Fig. 1 A ); number 3–5 per fascicle. See also Dew (1959: 35, fig. 11 C–G) for descriptions of chaetae.

Distribution: Australia and New Zealand.

Figures

FIGURE 1. A – F: Galeolaria caespitosa Lamarck 1818, from Port Hacking, NSW, BM (NH) 1959.10.19.9 – 19 determined and presented by B. Dew. A: Whole worm. B, Anterior end of worm; the operculum clearly inserted independently of the branchial radioles of both sides. C, Anterior end of a worm viewed from the left, showing the following. Unfringed interradiolar membranes, an opercular plate bearing a marginal palisade of short rods, a group of medial spines, and a winged opercular peduncle. Note the mid-dorsal longitudinal groove along the peduncle which is a continuation of the faecal groove. D, Opercular peduncle viewed dorsally, showing the longitudinal mid-dorsal groove for passage of faecal matter. It also shows that the mid-dorsal rod of the marginal palisade of rods is specially adapted for deflecting faecal material wafted along the faecal groove of the opercular peduncle outwards, and away from the branchial crown. E & F, show opercular spines and basal plates; see text for description.