Phylum Arthropoda
Subphylum Crustacea
Class Copepoda
Order Calanoida
Family Epacteriscidae

Azygonectes intermedius Fosshagen & Iliffe, 2004

	Azygonectes intermedius: after Fosshagen & Iliffe, 2004

Taxonomic Characterization: Prosome with five well-defined pedigerous somites. Urosome four-segmented with second and third urosomites of subequal length. Caudal rami slightly asymmetrical, caudal seta II short and spinous, seta V on left side extremely elongate. Rostrum elongate with two closely set filaments at tip. Antennule indistinctly 27-segmented, with segments 10 and 11 partially fused, reaching beyond caudal rami. Antenna with endopod slightly longer than exopod, second endopodal segment with nine setae on inner lobe. Gnathobase of mandible ventrally with two strong multicuspid teeth; palp with two-segmented endopod and with three setae on basis. Maxillule well developed but with some reduction in number and length of setae along inner margin of endopod. Maxilla with well-defined articulation between praecoxa and coxa, long and flexible setae on praecoxal and coxal endites. Maxilliped with long and flexible setae along syncoxa; endopod unmodified with flexible setae, third segment slightly elongate. Leg 1 with two outer spines on third exopod segment, slender and with a filament at tip. Legs 2 and 3 with two outer spines on third exopod segment, proximal one short and stout; leg 3 with outer stout spine on basis. Legs 4 and 5 with outer seta on basis and three outer spines on third exopod segment.

Disposition of Specimens: All specimens were deposited in the Museum of Natural History, London: female holotype BM(NH) 2003.581; adult female paratype BM(NH) 2003.582.

Ecological Classification: Stygobitic

Size: Total body length of 1.69 and 1.77 mm.

Number of Species in Genus: One

Species Range: Known only from Sanctuary Blue Hole, The Bluffs, South Andros Island and Basil Minn's Blue Hole, Great Exuma Island (Fosshagen & Iliffe, 2004).

Closest Related Species: Awaiting the discovery of the male, Azygonectes is currently placed among the most pleisiomorphic genera of the family in a systematic position between Balinella and the Erebonectinae. A key character for females in the two epacteriscid subfamilies is the number of outer spines on the third exopodal segment of legs 3-5, with two spines in Erebonectinae and three spines in Epacteriscinae. Azygonectes intermedius deviates from this pattern having two outer spines on leg 3 and three spines on legs 4 and 5.

Habitat: Anchialine limestone caves.

Ecology: Specimens were collected in fully marine waters at depths of 35-50 m in Sanctuary and 20-36 m in Basil Minns using a plankton net. The sample from Sanctuary Blue Hole contained large numbers of Mastigodiaptomus nesus Bowman; other calanoids recorded in small numbers were: Bomburiella gigas Fosshagen, Boxshall & Iliffe, Oinella longiseta Fosshagen, Boxshall & Iliffe, one copepodid of Bofiiriella, Exumellma bucculenta Fosshagen & Iliffe, Stargatia palmeri Fosshagen & Iliffe, and an undetermined species of Exumella. The species composition as well as the water quality is very similar to that of the nearby Stargate Blue Hole. In addition to copepods, a characteristic stygobitic fauna including thermosbaenaceans, halocyprid ostracods, cirolanid isopods, remipedes and polynoid polychaetes were also sampled. The Basil Minn's sample contained several Ridgewayia sp., a few specimens of Paramisophria sp., Stargatia palmeri and an unidentified calanoid.

Life History: Only 2 females specimens have been collected.

Conservation Status: Restricted to two anchialine caves - one in the Exuma Cays and the other on South Andros Island.

Reference:

Link:

Contributor: Audun Fosshagen, University of Bergen, Norway