Chaetacanthus pomareae
Creators: name: Salazar-Silva, Patricia
name: López-Sánchez, Daniel A.
name: Salazar-Vallejo, Sergio I.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Phyllodocida
Polynoidae
Chaetacanthus
Chaetacanthus pomareae

description: Chaetacanthus pomareae (Kinberg, 1856)
Figures 17, 18
Lepidonotus pomareae Kinberg, 1856: 383; Kinberg 1858: 10, Pl. 3, Fig. 9, Pl. 10, Fig. 47; Seidler 1924: 20 (key), 32–33. Chaetacanthus pomareae: Hartman 1948: 27–29, Pl. 3, Figs 13, 14.
Type material. Central South Pacific, French Polynesia. Holotype of Lepidonotus pomareae Kinberg, 1856, SMNH 395, Tahiti, 20°S, 150° W, Freg. Eugenie Exped. 1851–53.
Diagnosis. Chaetacanthus with branchial filaments single, thick lobes; elytra with globular micropapillae and microtubercles; round macrotubercles larger on first pair of elytra; conical macrotubercles in following elytra, macrotubercles up to five times longer than wide, basally spinous, tips long, smooth; elytra without large, amber-colour macrotubercles arranged in honeycomb like groups.
Description. Holotype in poor condition, without posterior end, 1.2 cm long, 0.3 cm wide, 23 segments. Data from description and illustrations by Kinberg (1858) given in parentheses.
Prostomium bilobed, hexagonal, as long as wide; two pairs of eyes, without pigmentation; anterior pair on middle part, posterior pair near to posterior margin (Fig. 17A). Facial tubercle prominent, pointed. Median antenna with ceratophore long, inserted frontally, style long, expanded subdistally, tip filiform (slightly longer than laterals). Lateral antennae with ceratophores inserted terminally, styles thin, shorter than median antenna, similar in shape to median antenna (Fig. 17A). Palps with stout papillae, tapered, as long as median antenna. Pharynx missing (previously removed; 12 pairs of marginal papillae; jaws with smooth cutting edge).
Tentacular segment not visible dorsally; tentaculophores long, thin, with chaetae; tentacular cirri similar in shape to antennae. Segment two dorsally projected on prostomium as a nuchal rounded lobe (Fig. 17A).
Elytra with fringe of short papillae; surface granular with numerous microtubercles, and digitiform papillae (Fig. 17G). First pair of elytra with microtubercles and macrotubercles spherical or hemispherical, spinous (Figs 17B, C; 18A, F), larger in elytrophoral plug area (Fig. 18B). Elytra of median and posterior segments oval with fringe of slender papillae (Figs 17F; 18C, E), surface with numerous conical macrotubercles, amber incolour, sclerotized, basally spinous, tips long (Figs 17D, E; 18D, E, G, H), larger macrotubercles over elytrophoral plug area.
Parapodia biramous, with branchial filaments laterally to eytrophores, cirrophores and between neuropodia. Notopodia shorter than neuropodia. Neuropodia with postchaetal rounded lobe, prechaetal lobe with a small acicular lobe, acicular tips slightly projected. Dorsal cirri short, thin, smooth, with subdistal swelling, tips filiform. Cirrophores short. Ventral cirri thin, short, tips filiform. Nephridial papillae from segment seven.
Notochaetae abundant, long, slender, with minute rows of spines. Neurochaetae thicker than notochaetae; upper bundle with shorter chaetae, tips with subdistal spines. Pygidium with anal cirri long, similar to dorsal cirri, anus terminal in last segment.
Remarks. The specific epithet given by Kinberg most probably refers to Queen Animata Pômare, who reigned in Tahiti from 1827 to 1877, an account of whom is given by O’Brien (2006). The type specimen is the only known record.
The holotype of C. pomareae (Kinberg, 1856) is about half as long as the critical size indicated by Augener (1927), and herein confirmed; however, instead of having many globular macrotubercles densely packed, there are just a few, and they have very long, conical macrotubercles in the elytrophoral plug area. Consequently, we are confident about using the type, size, and density of globular macrotubercles as diagnostic features, and that C. pomareae differs from its congeners by having a low density of globular macrotubercles, and many conical macrotubercles.
Type locality. Tahiti, French Polynesia (20°S, 150° W).
Distribution. Only known from the locus typicus.
description: Published as part of Salazar-Silva, Patricia, López-Sánchez, Daniel A. & Salazar-Vallejo, Sergio I., 2020, Revision of Chaetacanthus Seidler, 1922 (Annelida, Phyllodocida, Polynoidae), pp. 395-422 in Zootaxa 4885 (3) on pages 415-417, DOI: 10.11646/zootaxa.4885.3.5, http://zenodo.org/record/4296773