Antarctic Science

Biological Sciences

Short Note: Circumpolar distribution of the pycnogonid-ectoparasitic gastropod Dickdellia labioflecta (Dell, 1990) (Mollusca: Zerotulidae)

Stefano Schiaparellia1 c1, Marco Oliverioa2, Marco Taviania3, Huw Griffithsa4, Anne-Nina Lörza5 and Giancarlo Albertellia6

a1 Museo Nazionale dell'Antartide (MNA), Università di Genova, Viale Benedetto XV n° 5, Genova I-16132, Italy

a2 Dipartimento di Biologia Animale e dell'Uomo, Università La Sapienza, Viale dell'Università 32, Roma I-00185, Italy

a3 Istituto di Scienze Marine (ISMAR), CNR, Via Gobetti 101, Bologna I-40129, Italy

a4 British Antarctic Survey, NERC, High Cross, Madingley Road, Cambridge CB3 OET, UK

a5 NIWA National Institute of Water & Atmospheric Research, Greta Point, Wellington, New Zealand

a6 Dipartimento per lo Studio del Territorio e delle sue Risorse (Dip.Te.Ris.), Università di Genova, Europa 26, Genova I-16132, Italy

The Antarctic gastropod Dickdellia labioflecta (Dell, 1990) (originally described as Laevilittorina (Corneolittorina) labioflecta) is an obligate parasite of pycnogonids, which exploits their body fluids through the cuticular gland holes (Lehmann et al. 2007) and lays its eggs on the pycnogonid's legs where embryos complete their life cycle (Hedgpeth 1964, Sirenko 2000, Lehmann et al. 2007). The ecology of D. labioflecta appears to be unique, as no other examples of such a specialized parasitic behaviour on pycnogonids are known. This life-style and the related anatomical specializations (gut and digestive gland morphology), prompted the erection of a new genus, Dickdellia Warén & Hain, 1996 provisionally included in the family Zerotulidae (Warén & Hain 1996). Although information is quite scant, to date, two pycnogonid host species are known for Dickdellia: Colossendeis megalonyx megalonyx Fry & Hedgpeth, 1969 (Lehmann et al. 2007) and Nymphon isabellae Turpaeva, 2000 (Sirenko 2000).

(Received January 16 2008)

(Accepted January 28 2008)