[Annelida] Asetocalamyzas laonicola is a family-swapping male dwarf

Geoff Read via annelida%40net.bio.net (by g.read from niwa.co.nz)
Thu May 22 03:38:05 EST 2008


Vortsepneva, E., Tzetlin, A., Purschke, G., Mugue, N., Hass-Cordes, E.
& Zhadan, A. (2008) The parasitic polychaete known as Asetocalamyzas
laonicola (Calamyzidae) is in fact the dwarf male of the spionid
Scolelepis laonicola (comb. nov.). Invertebrate Biology, efirst status,
DOI: 10.1111/j.1744-7410.2008.00137.x

 Reprint requests: vortcepneva from mail.ru

Abstract: The morphology of the obligately ectoparasitic polychaete
Asetocalamyzas laonicola was studied by light and electron microscopy,
and its taxonomic position was determined using molecular methods. The
parasite has an extensive coelomic cavity, complete septae, and
well-developed segmental nephridia, circulatory, and digestive systems.
The nervous system is rudimentary and without ganglia. The parasite’s
anterior region penetrates the tissues of the host, and opens into the
host’s body cavity. The epidermal tissues of the parasite and the host
are highly integrated in the area of contact, and the parasite’s
cuticle is continuous with that of the host. Blood vessels of the
parasite and the host may interlace in the fusion zone. The dorsal side
of the parasite faces the dorsal side of the host. All parasites were
males, but all hosts were females. In order to elucidate the uncertain
systematic position of the parasite, molecular systematic studies were
conducted. Parasite and host 18S rDNA sequences were virtually identical
and revealed that both belong to the spionid cluster. These sequences
differed from those of Scolelepis squamata and Scolelepis bonnieri by
2.7% and 0.9%, respectively. In addition, of seven partial sequences of
the mitochondrial COI gene obtained from three parasites and four hosts,
six were identical, and in one host–parasite pair, COI sequences
differed by one substitution. Partial ITS2 sequences from one
host–parasite pair were analyzed and also found to be similar but
not identical, with two indels in a 645-bp alignment. We conclude that
the parasite is in fact a dwarf male of its conspecific spionid female
host. Consequently, A. laonicola is transferred to Scolelepis
(Spionidae), forming the new combination Scolelepis laonicola 


Vortsepneva, E.V., Zhadan, A.E. & Tzetlin, A.B. (2006) Spermiogenesis
and sperm ultrastructure of Asetocalamyzas laonicola Tzetlin, 1985
(Polychaeta), an ectoparasite of the large spionid Scolelepis cf.
matsugae Sikorsfi, 1994, from the White Sea. Scientia Marina, 70,

Tzetlin, A.B. (1985) [Asetocalamyzas laonicola gen. et sp. n., a new
ectoparasitic polychaete from the White Sea.] Zoologicheskii Zhurnal,
64, 296-298.

Most interesting! Have fun updating your databases (and your



 Geoff Read <g.read from niwa.co.nz>

More information about the Annelida mailing list