NIWA Guide to Polychaeta | Shore polychaetes | Pick shore group | Pick shore family | Shell polychaetes
Polynoidae Family Polynoidae (polynoid/scale worm)
Phyllodocida (Annelida: Polychaeta)
About Family Polynoidae polychaetes in New Zealand.  
How to recognise the family: The polynoid scale worms are dorsoventrally flattened, often rather oval-shaped predators. Their upper surface is usually fully protected by a number of large overlapping plates, the elytra, each of which may be ornamented and fringed with papillae, tubercles and hairs. The attachment point of each elytron is near its centre, like a mushroom. It is not strong and elytra are frequently lost from the body during handling. The prostomium is a distinct head with two eye pairs, three antennae and palps. The proboscis has four chitinous jaws inside a fringe of projecting papillae. The notopodium is variably developed. Elytra tend to occur on alternate chaetigers, at least anteriorly, and the chaetigers without elytra have dorsal cirri. Chaetae are simple, often with two-toothed ends in neurochaetae, and usually with fine, variably-developed rows of denticulations which appear serrated along one edge. An anal cirri pair is present. Identification to genus is based on head structures, particularly the arrangement of antennae, together with the number of elytra and details of elytral ornamentations, parapodial and chaetal morphology. Polynoids worldwide are very diverse at the generic level. They are frequently commensals of other animals, and may specialise in living on species of various corals, sponges, asteroids, echinoids, ophiuroids, holothurians, and enteropneusts. Several live inside the tubes of other polychaetes. Adult size: To 100 mm in length.
How to recognise the New Zealand genera: Not easily summarised in a few words but Lepidonotus will often be the genus if the worm is rather flat, smallish and short, and there are 12 only elytral pairs. Lepidastheniella has many more elytra, in Disconatus the elytra are reduced, and in Euphione they are very ornate. Harmothoe and Harmothoinae species usually have a pair of small horn-like projections called frontal peaks on the head.
Quick pick shore species: There are certainly many subtidal New Zealand species yet to be discovered. A number of new species have been recorded from very deep water in recent years. The commonest shallow-water species is the mottled grey-brown Lepidonotus polychromus Schmarda, 1861, with the 12 elytral pairs typical of, but not unique to, the genus. Another five Lepidonotus species have been described. The largest New Zealand polynoid is the formidable-looking Euphione squamosa (Quatrefages, 1865), which has elytra fringed with long tubercles and dorsal branchial papillae present under the elytra (see Thomson's description under the name Lepidonotus giganteus Kirk, 1879). The slender, elongate, intertidal commensal species Disconatis accolus (Estcourt, 1967), formerly known as Lepidasthenia, has reduced, unornamented elytra, the first pair small, the remainder vestigial, and notochaetae are absent. Another common species is Lepidastheniella comma (Thomson, 1902), which has pigment in dorsal bars and in comma-shaped spots on the elytra. It may occur as a commensal in polychaete tubes, but also free-living.
Possible misidentifications: Polynoidae are confusable with the other scales worms, especially the Sigalionidae. However, sigalionids have compound chaetae and lack the polynoid flattened appearance.
Distributions, lifestyle, and habitat: Lower intertidal and subtidal to deep sea throughout New Zealand. Polynoids generally occur crawling on various firm surfaces, including shelly substrata. Lepidonotus spp. and more rarely Euphione squamosa, may be found creeping along under unsedimented boulders in rocky shore pools and amongst algal holdfasts. However, Disconatis accolus is sand-dwelling, sharing the tube of the common intertidal maldanid polychaete Macroclymenella stewartensis. Disconatis accolus is also occasionally found in tubes of other polychaetes and was first described associated with the lugworm Abarenicola affinis. Lepidastheniella comma was described from terebellid tubes.
Abundance: Conspicuous, but never abundant.
Taxonomic note: Benhamipolynoe antipathicola (Benham, 1927 as Lepidasthenia) and Tottonpolynoe symantipatharia Pettibone, 1991, dwell on the deep-water black corals, Parantipathes and Antipathes spp. as indicated by the specific names. The name of the first species is misused in Morton and Miller (1973: p494), as applied to an otherwise unidentifiable sandy beach scale worm. The two black coral dwellers live in grooves or tunnels on the stems of their hosts.
References: (Augener 1924b: p274-295), (Averintsev 1978: p53-54,61-66 f1,5-6), (Benham 1927: p64-67, f11-13, P1), (Benham 1950: p5-11, f1-2), (Day & Hutchings 1979: p86-92), (Ehlers 1904: p7-9, P1.1-9), (Estcourt 1967: p68-70, f1-4), (Hanley & Burke 1988: p5-16, f1-5), (Kirkegaard 1956: p64-66 f1-2), (Kirkegaard 1995: p11-20, f5,8-9,11), (Knox 1951b: p62-64, f1-5), (Knox 1956: p43-50, f12-17), (Knox 1960a: p83-95, f15-78), (McIntosh 1885: p69-70, 93-94, 118-119, 121-122, P8a.1-2, 10a.5-6, 12a.4-6,9-11, 13.6-8, 14.1,6, 16.1, 18.5, 27.4), (Pettibone 1991: p722), (Morton & Miller 1973: p176-178, 494-495, P9.2), (Schmarda 1861: p153, 155, 158, P36.306-307), (Thomson 1900: p974-986, P60-62), (Thomson 1902: p241-242).
(Full citations at Family pages literature cited list.)

Species in the guide: Rock Species: Lepidastheniella comma | Lepidonotus polychromus
Sand Species: Disconatis accolus
Shell Species: None for this family.

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Last modified by G. Read, 25/07/2004    (dd/mm/yy)