NIWA Guide to Polychaeta | Shore polychaetes | Pick shore group | Pick shore family | Shell polychaetes
Hesionidae Family Hesionidae (hesionid)
Phyllodocida (Annelida: Polychaeta)
About Family Hesionidae polychaetes in New Zealand.  
How to recognise the family: Hesionids are active carnivorous worms, somewhat intermediate in appearance between nereidids and syllids. They are found in crevices and amongst the plant and animal growths on hard substrata, with some species occurring commensally on echinoderms and with other larger tube-dwelling worms. They are never very large and are rather fragile. The head is usually a small rectangle with a pair of slender simple or jointed palps, a pair of antenna, sometimes with a third median antenna located further back, and two pairs of lensed eyes. The peristomium has segments fused to it so that there are two to eight pairs of tentacular cirri crowded on the side of the head. The proboscis has papillae but usually lacks chitinous jaws. Notopodial lobes and chaetae are variably developed and may be absent. Notochaetae are mostly simple capillaries or spines but sometimes forked chaetae are present. Neurochaetae are slim compound falcigers and spinigers. The dorsal cirri are long and annulated like those of syllids. There is usually a pair of anal cirri and sometimes an anal disk. Important generic characters include the number of tentacular cirri and antennae, and the form of the parapodia, but assignment to current genera may be considered of dubious value as there are "many unclear generic concepts and an ill-defined hierarchy of characters," to quote a recent review. Adult size: Up to 40 mm in length but Microphthalmus riseri is rarely 10 mm long.
How to recognise the New Zealand genera: See species below. In general the subleties, complexities, and uncertainties are such that a recent revision such as Pleijel (1998) should be consulted.
Quick pick shore species: The New Zealand species are little known and only four names are in the literature although several other unreported species exist. The commonest large hesionid is a rapid-moving brown species with six pairs of tentacular cirri, a median antenna, and with notochaetae absent or no more than 1-2 per chaetiger. It is unlikely to be misidentified and has been known as either Podarke angustifrons (Grube, 1878) or Ophiodromus angustifrons after a species from the Philippines, although this name probably needs re-evaluation. Microphthalmus riseri Westheide, 1994, a comparatively minute hesionid (but see taxonomy), has an anal lobe rather than anal cirri, and very slender cirri and antennae.
Possible misidentifications: None
Distributions, lifestyle, and habitat: Lower intertidal and subtidal to deep sea throughout New Zealand. Ophiodromrus angustifrons occurs in algal turf and under stones. Microphthalmus riseri occurs at or near the sediment surface on sheltered sand beaches.
Abundance: Common.
Taxonomic note: Parasyllidea blacki (Knox, 1960) is an eyeless species from deep water. Genus Microphthalmus is suggested to be related more closely to Family Pilargidae than Hesionidae.
References: (Augener 1924a: p40-42), (Hilbig 1994b: p243-269, f9.1-10), (Knox 1960a: p98-99, f88-91), (Pleijel 1998), (Westheide 1994: p45-53, f1).
(Full citations at Family pages literature cited list.)

Species in the guide: Rock Species: Ophiodromus angustifrons
Sand Species: Microphthalmus riseri
Shell Species: None for this family.

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