New Zealand Journal of Zoology abstracts
Two new and peculiar species of Grania (Annelida: Clitellata:
Enchytraeidae) inhabiting Tasmanian estuaries
EMILIA ROTA
Dipartimento di Biologia Evolutiva
Università di Siena
Via P.A. Mattioli 4
I-53100 Siena, Italy
CHRISTER ERSéUS
Department of Invertebrate Zoology
Swedish Museum of Natural History
Box 50007
SE-104 05 Stockholm, Sweden
Abstract Grania tasmaniae sp. n. and
G.
dolichura sp. n. are described from sediments collected at high- and
low-water mark in estuarine localities around Tasmania. They are the first
named records of
Grania from the southeastern corner of Australia, and
the only members of the genus in Pacific waters known to possess the head
organ.
Grania tasmaniae has unusual spindle-shaped coelomocytes and
large, round spermathecal ampullae deeply penetrated by the ectal ducts.
Grania dolichura is a relatively thin, elongate worm with trumpet-shaped
penial stylets but otherwise simple reproductive structures. Its somatic
traits, however, are startling: the segment number is very high (up to 108) and
the dorsal vessel exceptionally long (commencing as far back as segment
LXXVIII), these two features being significantly correlated. We suggest that
the increased length of body and unique vascular arrangement may enable
G.
dolichura to exploit deeper food sources, with the tail performing the
respiratory exchange being positioned in a shallower, more oxidised layer.
Grania dolichura tolerates a salinity range of 11-35%.
Keywords Enchytraeidae; Grania tasmaniae sp. n.;
Grania dolichura sp. n.; head organ; blood vessels; adaptations to life
in the sediment; Tasmania
Z99036
Received 13 September 1999; accepted 8 February 2000
PDF file of entire paper: medium quality (1777K); (scanned from paper original: notes about this process)
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