Abergasilus

Taxobox
name = "Abergasilus amplexus"
regnum = Animalia
phylum = Arthropoda
subphylum = Crustacea
classis = Maxillopoda
subclassis = Copepoda
ordo = Poecilostomatoida
familia = Ergasilidae
genus = "Abergasilus"
species = "A. amplexus"
binomial = "Abergasilus amplexus"
binomial_authority = Hewitt, 1978

"Abergasilus amplexus" is a species of parasitic copepod endemic to euryhaline habitats in New Zealand. It is currently the only known species in the genus "Abergasilus". The main host appears to be "Anguilla australis": in Lake Ellesmere, infestation rates on this eel approach 100%, sometimes with over 100 parasites on the gills of a single fish. Other recorded host species include "Anguilla dieffenbachii", "Arripis trutta", "Carassius auratus", "Galaxias maculatus", "Perca fluviatilis", "Pseudophycis bachus", "Retropinna retropinna", "Rhombosolea leporina", "Rhombosolea plebeia" and "Rhombosolea retiaria".

This species is unique among ergasilids in that it only has three pairs of legs: the fourth and fifth pairs are reduced to single spines or completely absent. The second antenna is very distinctive, hooks on the last and penultimate segments creating an obviously claw-like structure, more obvious in the female. The male is free-living, forming part of the plankton. Both sexes have an average length of 0.5 mm.

References

*cite journal |quotes=no |url=http://www.rsnz.org/publish/nzjmfr/1978/22.php |title="Abergasilus amplexus" gen. et sp. nov. (Ergasilidae; parasitic Copepoda) from fishes in Lake Ellesmere, New Zealand |journal=New Zealand Journal of Marine and Freshwater Research |volume=12 |issue=2 |year=1978 |author=G. C. Hewitt |pages=173–177
*cite journal |quotes=no |url=http://www.rsnz.org/publish/nzjmfr/1981/31.php |title="Abergasilus amplexus" Hewitt, 1978 (Ergasilidae: Copepoda) from New Zealand, with a description of the male |journal=New Zealand Journal of Marine and Freshwater Research |volume=15 |year=1981 |author=J. B. Jones |pages=275–278