NIWA Guide to Polychaeta | Shore polychaetes | Pick shore group | Pick shore family | Shell polychaetes |
Spionidae | Family Spionidae (spionid)
Spionida (Annelida: Polychaeta) |
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About Family Spionidae polychaetes in New Zealand. | ||||
How to recognise the family: | Spionids are generally small slender active worms, with head palps used for feeding, strap-like dorsal gills, lamellae-like parapodial lobes, usually best developed anteriorly, and usually with hooded-hook chaetae, especially in neuropodia, as well as simple capillaries. The palps arise dorsally on either side of a narrow prostomium and are readily cast off or sacrificed to predators, which means they are often missing when examined. A number of simple eyespot pairs are usually present at the side of the prostomium. Prostomium shape varies with genus (see below). Parapodial lobes are lamellar and largest anteriorly. Dorsal strap-like gills are associated with the notopodial lobes of the anterior parapodia and their distribution and degree of separation from the lobes is very significant. Spionid chaetae mostly consist of winged capillaries and hooded hooks. The latter usually do not begin until around chaetiger 10-20, appearing first in the neuropodia, and may be absent in the notopodia. A single, sharp-curved chaeta called a sabre chaeta may be present as the ventral-most neurochaeta. Spionid pygidial structures are varied and include short cirri (one to three pairs or many), lobes, cups, and plates. Adult size: To 150 mm long and 10 mm diameter, but more usually 10-30 mm. Spionids are mostly small, some even thread-like, but large species exist. | |||
How to recognise the New Zealand genera: | The prostomium tip may be variously conical (Scolelepis, Aonides, Prionospio), rounded (some Laonice, Polydora and Microspio), notched (some Microspio and Polydora group), chisel-like (some Prionospio species), or bluntly triangular with lateral extensions (Scolecolepides, Malacoceros, Rhynchospio and some Spiophanes). Prostomium shape alone is inadequate to suggest generic placement because more than one type may occur within some genera. Paraprionospio and some Prionospio have accessory pinnules or lamellae on the gills, whereas Spiophanes lacks gills, and has a unique crook-like neurochaeta on chaetiger one. In Polydora the gills begin posterior to the fifth chaetiger. In Scolelepis the gills begin on chaetiger two and are fused to the chaetal lobes. A large sub-group of spionids i.e. Polydora, Boccardia and their allies, have thick spine-like chaetae on chaetiger five, and neurochaetal hooks from chaetiger seven or eight. Many of these species bore into calcareous surfaces including mollusc shells, probably mainly by chemical attack aided in minor part by the chaetiger five spines. | |||
Quick pick shore species: | The commonest shallow-water spionids include Scolecolepides benhami Ehlers, 1907, a large species with frontal horns and gills from chaetiger one, Boccardia syrtis (Rainer, 1973) with brush-topped chaetiger five spines and posterior curved notochaetal spines, Aonides trifida Estcourt, 1967, with a sharp-pointed prostomium and 12 or more pairs of gills beginning from chaetiger two, and Prionospio aucklandica Augener, 1924, with three pairs of pinnate gills beginning from chaetiger two. Scolelepis antipoda (Augener, 1926) lacks a prominent antenna on the caruncle, unlike the much smaller intertidal Scolelepis sp. with which it may co-occur. Microspio maori Blake 1984, with gills from chaetiger two and four ventral anal cirri, is the commonest of several small Microspio and Spio (gills from chaetiger one) species. See below for mention of other species, including shell-borers. | |||
Possible misidentifications: | Spionids and paraonids both have serial branchiae, however paraonids lack palps, don't have hooded hook chaetae, and are infrequently encountered intertidally. Polydora-group and Prionospio-group have many New Zealand species and are difficult to identify unless complete and in good condition. | |||
Distributions, lifestyle, and habitat: | Spionids occur across the shore from the upper intertidal, and also subtidally to the deep sea. Spionids are very common polychaetes in all sandy substrata, and rather infrequent on rocky shores. Spionids selectively deposit-feed on the substratum surface by exploring it with a pair of feeding palps, which in this family are long ciliated filaments, usually with a ciliated groove for transporting particles to the mouth. The palps may also be used to catch plankton and drifting particles from the water. Spionids are ubiquitous burrowers in shallow water fine sands, either in fixed sand tubes or free-wandering. Scolecolepides benhami is rarely absent in sandy estuaries, often occurring in a dense zone high on the shore, although large adults tend to occur further down towards low water mark. A close relative, the larger Scolecolepides freemani Mitchell & Edwards, 1988 occurs upstream in some rivers, usually in sticky mud in near freshwater conditions. The thread-like Aonides trifida is also common in estuaries. Prionospio aucklandica is common at low water mark in harbours and estuaries. Microspio maori is occasionally abundant in the intertidal of harbours and sheltered shores. Scolelepis spp. populations tend to occur in small localised dense patches on medium-grained open beaches. The Polydora group of species specialise in boring into shells. Boccardia acus (Rainer, 1973) bores into the upper exposed shell of the cockle Austrovenus stutchburyi and and Boccardia knoxi (Rainer, 1973) is very common on paua Haliotis iris. Polydora hoplura ClaparFde, 1870 and Boccardia otakouica Rainer, 1973, cause extremely large blisters on the inner lips of the horse mussel Atrina pectinata. Polydora websteri Hartman, 1943, Polydora haswelli Blake and Kudenov, also cause blisters inside shells of the Pacific oyster Crassostrea gigas. There are additional common Polydora group species such as Dipolydora armata (Langerhans, 1880), which bore into calcareous algal crust (as does B. knoxi), and Boccardia chilensis Blake and Woodwick, 1971, which is common living in narrow rock crevices. Several other Polydora group species live free in tubes in the sand. The tubes of the most widely-occurring species, Boccardia syrtis, form a visible fine turf on sandstone reefs and on some sand flats. Smaller numbers of other species, such as Pseudopolydora paucibranchiata (Okuda, 1937) and Prionospio aucklandica, are usually intermingled in these colonies. Prionospio yuriel Wilson, 1990 and P. multicristata (Hutchings & Rainer, 1979) occur subtidally in harbours. P. pyramidalis (Hutchings & Turvey, 1984) is the only rocky shore Prionospio species. Spio aequalis Ehlers, 1904 is (or perhaps was) an extremely large rocky shore species. However, no new specimens have been found for fifty years. |
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Abundance: | Common to extremely abundant. | |||
Taxonomic note: | The family is well investigated, and the large number of genera are mostly taxonomically stable and distinct, although some recent new ones may be reabsorbed in future. The number of New Zealand spionid species known is large and many occur abundantly. They are also the most conspicuous, common, and longest-lived larval polychaetes in the plankton, especially those of the Polydora group. Not all spionids in New Zealand may be native as they readily hitchhike between countries in ship fouling and as larvae in ballast water. As well as Prionospio aucklandica here are at least 10 other Prionospio species occurring in subtidal coastal waters, all usually smaller than P. aucklandica. | |||
References: | (Augener 1924a: p69-71, f24), (Augener 1926: p158-164, f1-3), (Blake 1984: p148-159, f1-5), (Blake 1996c: p81-223, f4.1-38), (Day & Hutchings 1979: p122-124), (Ehlers 1904: p40-44, P5.18-21, 6.1-4), (Ehlers 1907: p14-16, f4-6), (Estcourt 1967: p73-75, f5-10), (Light 1978: p1-211, f1-185), (Mitchell & Edwards 1988: p391-395, f1), (Morton & Miller 1973: p526 (spionid names used are almost all incorrect and should be ignored)), (Rainer 1973: p545-564, f1-10), (Read 1975: p395-419, f1-7), (Wilson 1990: p243-274, f1-93). (Full citations at Family pages literature cited list.) |
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Species in the guide: | Rock Species: Boccardia chilensis | Prionospio pyramidalis | |||
Sand Species: Aonides trifida | Boccardia acus | Boccardia syrtis | Microspio maori | Polydora cornuta | Polydora haswelli | Prionospio aucklandica | Pseudopolydora paucibranchiata | Scolecolepides benhami | Scolecolepides freemani | Scolelepis antipoda | ||||
Shell Species: Boccardia acus | Boccardia chilensis | Boccardia knoxi | Boccardia lamellata | Boccardia otakouica | Boccardia proboscidea | Carazziella quadricirrata | Dipolydora armata | Dipolydora dorsomaculata | Dipolydora giardi | Polydora cornuta | Polydora haswelli | Polydora hoplura | Polydora websteri | ||||
Internet sources: |
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The information provided by this page and by the pages of the "more information" links is held in a structured form for rapid and frequent updating and improvement. Descriptive text is compiled from a number of database fields, some of which may occasionally be empty. Last modified by G. Read, 25/07/2004 (dd/mm/yy) |