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Description of Psammodrilus aedificator sp.n. (Polychaeta), with Notes on the Arctic Interstitial Fauna of Disko Island, W. Greenland *
Author(s) -
KRISTENSEN REINHARDT MØBJERG,
NØRREVANG ARNE
Publication year - 1982
Publication title -
zoologica scripta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 64
eISSN - 1463-6409
pISSN - 0300-3256
DOI - 10.1111/j.1463-6409.1982.tb00538.x
Subject(s) - biology , fauna , sponge spicule , arctic , dorsum , anatomy , seta , type locality , spicule , ecology , zoology , genus
Psammodrilus aedificator sp.n. is described from an arctic subtidal sandy habitat at 2–3 m depth. The new species represents a link between the two genera Psammodrilus and Psammodriloides , but it has a distinct warty collar shared only with Psammodrilus balanoglossoides . This unique structure was investigated by transmission electron microscopy. Each wart consists of one large cell with microvilli arranged in a hexagonal pattern. The collar epidermis is devoid of cilia. The head consists of prostomium and peristomium, the thorax consists of 7(8) segments, both tagmata totally ciliated. Each of the six pairs of cirri have an aciculum. The abdomen consists of 20 segments and is ciliated except for the dorsal sulcus. Psammodrilus aedifcator sp.n. is sessile and forms a “house” of agglutinated sand grains. Only females (8 mm) and a few juveniles (4 mm) were found in July‐August. Mature eggs are extremely large (310 μm), evidently an adaptation to arctic conditions. Throughout the year the interstitial fauna at the type locality was rich, both in species and individuals. Some of the associated fauna included coelenterates, many turbellarians, nemerteans, chaetonotid gastrotrichs, archiannelids and polychaetes and, less abundantly, a few gnathostomulids, macrodasyid gastrotrichs, nematodes, eutardigrades, halacarids, harpacticoid copepods and ostracods.