Cryptonectes brachyceratus Fosshagen & Iliffe, 2004
Cryptonectes brachyceratus: lateral & dorsal views after Fosshagen & Iliffe, 2004
Taxonomic Characterization: Female. Prosome with five well-defined pedigerous somites. Lateral border of cephalosome with distinct concave swing in middle. Urosome three-segmented. Caudal rami symmetrical with caudal seta II short and spinous. Rostrum rounded with two filaments at tip. Antennule 25-segmented, short and reaching slightly beyond first pedigerous somite. Antenna with very short condensed endopod, about half length of exopod. Mandible with strong gnathobase bearing bifid ventral-most tooth and row of rounded teeth towards dorsal part; palp with small one-segmented endopod and four-segmented exopod. Maxillule with reduced number of setae particularly on coxa, basis and endopod with two setae on each of coxal endite and proximal basal endite. Maxilla with relatively short unmodified setae except for long spinous setae distally on endopod. Maxilliped mostly with short spinous setae except for long and modified ones on endopod which bear distal row of stiff setules and thin flexible tip. Leg 1 with small outer seta on basis, two outer spines on third exopod segment slender and pinnate. Legs 2-5 with very strong and subequal outer spines of exopods, all with two outer spines on third exopodal segment; leg 3 with outer strong curved spine on basis; leg 5 with small inner seta on first exopodal segment.
Male. Urosome four-segmented. Right antennule 21-segmented with segments 1I-IV fused, long pointed process on penultimate segment 20. Fifth legs with pointed process distally on inner margin of left basis, exopods modified in distal part, three-segmented on right side and ending in curved pointed process, two-segmented on left side with last segment bearing outer falcate process; endopods three-segmented, only slightly modified (Fosshagen & Iliffe, 2004).
Disposition of Specimens: All specimens were deposited in the
Museum of Natural History, London: female holotype
from Liza Bay Cave BM(NH) 2003.583; adult male paratype from Norman's Pond Cave BM(NH) 2003.584;
adult female paratype from Virgo Blue Hole BM(NH) 2003.585.
Ecological Classification: Stygobitic
Size: Females total body length of 1.16 and 1.25 mm; male total body length 1.21 mm.
Number of Species in Genus: One
Species Range: Known from four caves located on three separate shallow water banks: Liza Bay Cave, Salinas Point, Acklins Island; Basil Minn's Blue Hole, Great Exuma Island, Norman's Pond Cave, Norman's Pond Cay, Exumas; Virgo Blue Hole, Sweetings Cay, near Grand Bahama Island (Fosshagen & Iliffe, 2004).
Closest Related Species: Cryptonectes brachyceratus exhibits several reductions and apomorphic characters both in mouthparts and swimming legs. Having two outer spines on the third exopodal segment of legs 1-5 in the female, this character connects the species to the two genera in the Erebonectinae in which this is a key character and one of the few apomorphic ones; for this reason the new genus is included in the subfamily. The mouthparts in the Erebonectinae are generally unmodified and showing some of the most plesiomorphic characters of the Calanoida. The new genus has several characters in common with the many genera of the Epacteriscinae, such as a short endopod of the antenna, reductions in the number of setae on the mandible and maxillule. The most extreme apomorphic state of these characters, however, is developed in Epacteriscus. A rare plesiomorphic character in Cryptonectes is the presence of an outer basal seta on leg 1, a character also found in Erebonectes and Bomburiella. Thus, the new genus shows a mosaic of characters from both subfamilies.
Habitat: Anchialine limestone caves.
Ecology: Specimens were collected in fully marine waters at depths of 0-5 m in Liza Bay, 10-60 m in Norman's Pond, 15-21 m in Virgo and 20-36 m in Basil Minns using a plankton net. Judging from the compact and stout appearance, the short antennule and strong spines on the outer margin of swimming legs, the animal seems to live a benthic life. Strong and specialized setae on the maxilla and maxilliped suggest raptorial feeding.
Life History: Collected specimens include 2 females and 2 males.
Only one specimen was found in each of four caves.
Conservation Status: Known from four anchialine caves on three separate platforms (banks) with deep water channels between them. Two of the caves, Norman's Pond and Basil Minn's, are on the Great Bahama Bank, Virgo on the Little Bahama Bank and Liza Bay on Acklins Island.
Contributor: Audun Fosshagen, University of Bergen, Norway
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