Kyphocalanus

Dataset
A new family and genus of calanoid copepods (Crustacea) from the abyss of the Atlantic Ocean: Rank
GENUS: Published in
Markhaseva, Elena L., Schulz, Knud (2009): A new family and genus of calanoid copepods (Crustacea) from the abyss of the Atlantic Ocean. Zootaxa 2304: 21-40, DOI: 10.5281/zenodo.275327

Classification

kingdom
Animalia: phylum
Arthropoda: class
Maxillopoda: order
Calanoida: family
Kyphocalanidae: genus
Kyphocalanus

description

Male. Unknown.

diagnosis

Diagnosis. Female. Cephalon in lateral view strongly bent anteriorly. Rostrum as two short, prong-like points. Cephalosome and first pedigerous somite and pedigerous somites 4 and 5 separate. Urosome very short comparatively, of 4 somites, genital-double somite being the largest. Antennule shorter than prosome. Basis, endopod segment 1 and exopod segment 1 of antenna without setae; endopod segment 2 with 3 or 4 setae on inner lobe; exopod segment 2 with 1 short seta. Mandibular gnathobase long and slender, with narrow cutting edge; basis of mandible with 2 setae, proximal seta with conspicuous thickening at one-third length; endopod segment 1 without setae, segment 2 with 9 setae; exopod 5 - segmented with 1, 1, 1, 1, and 1 setae. Praecoxal endite of maxillule with 3 slender setae; proximal basal endite without setae; distal basal endite with 1 seta and separate from endopod bearing 5 setae. Praecoxal and coxal endites of maxilla usually with 2 slender setae each; basal endite with 1 strong spine; endopod with 8 long and thick worm-like sensory setae. Praecoxal lobes of maxilliped syncoxa with 1 thin, slender and comparably short worm-like sensory seta on proximal lobe and 2 thick and long worm-like setae on medial lobe; distal lobe without seta, setal formula 1,2,0; coxal endite with 1 slender seta. P 4 coxa, basis, endopod, and exopod segment 1 with posterior surface spinulation or not. P 5 3 - segmented, exopod with 2 unequal spines (1 shorter, terminal and 1 longer, inner and subterminal spine).

discussion

Remarks. Synapomorphies for the genus Kyphocalanus are the presence of a knife handle-like basal part of the proximal seta of the mandibular basis and the maxillule distal basal endite and endopod separate and the distal basal endite bearing 1 seta only (vs 2 – 6 setae in other Bradfordians). In addition to the characters of the family, the new genus differs from the majority of other Bradfordian families / genera by the following derived characters: i) antenna basis without setae, shared with tharybid genus Brodskius Markhaseva & Ferrari, 2005, contrasting the presence of 1 – 2 setae in other Bradfordians; ii) antenna endopod segment 1 without setae, shared with Pseudophaenna Sars, 1902 (genus of unclear familial position) and some species of the tharybid genus Undinella Sars, 1900, and contrary to 1 – 2 setae in other Bradfordians; iii) antenna endopod segment 2 with fewer than 10 setae, shared with Pseudophaenna, but this segment with 11 – 15 setae in other Bradfordians; iv) maxillule proximal basal endite without setae, shared with Bradfordiella Andronov, 2007 (genus of unclear familial position), in contrast to the presence of 2 – 5 setae in other Bradfordians; v) maxilla proximal praecoxal endite with 2 setae, shared with Rostrocalanus and some species of Bradfordiella, but with 3 – 5 setae in other Bradfordians; vi) maxilla distal praecoxal endite and proximal coxal endite with 2 setae each, shared with some species of Bradfordiella, and contrary to 3 setae in other Bradfordians; vii) maxilla distal coxal endite with 2 setae, shared with Phaenna Claus, 1863 (family Phaennidae), but with 3 setae in other Bradfordians; viii) maxilla proximal basal endite with 1 setal element, shared with Bradfordiella, but with 3 – 4 setal elements in other Bradfordians; ix) 1 seta on maxilliped coxal endite is shared with some species of Undinella and Bradfordiella, in contrast to presence of 2 or 3 setae in other Bradfordian genera. The similar derived armament of some oral limbs of Kyphocalanus gen. nov. and Bradfordiella is assumed to have arisen in a parallel development and independently, and thus both genera are not considered to be closely related. This is corroborated by apomorphies not shared by Bradfordiella: i) praecoxal arthrite of maxillule with 3 setae (vs 9 in Bradfordiella); ii) distal coxal endite of maxilla with 2 setae (vs 3 setae in Bradfordiella); iii) maxilla distal basal endite plus endopod with 8 very long and thick, worm-like sensory setae, longer than all sclerotized setae of maxilla (vs only 6 short sensory setae of unclear morphology (Andronov 2007: 632) in Bradfordiella). In addition, the new genus does not share apomorphies of Bradfordiella: i) antennule of only 18 articulated segments (vs 24 in Kyphocalanus); ii) mandibular basis lacking setae (viz. 2 setae in Kyphocalanus); iii) maxillule with coxal and basal endites reduced (vs these endites well developed in Kyphocalanus); v) maxilliped praecoxal endites of syncoxa lacking setae (with 1, 2, 0 setae in Kyphocalanus).

etymology

Etymology. From “ kyphos ” (Greek, meaning bent), refers to the pronounced and strongly bent cephalon, viewed laterally. This characterization is combined with the existing generic name Calanus. Gender masculine.

materials_examined

Type species: Kyphocalanus atlanticus sp. nov., by monotypy.

Name

Homonyms: Kyphocalanus; Kyphocalanus; Kyphocalanus; Kyphocalanus