Boonyanusith, Chaichat, Sanoamuang, La-orsri & Brancelj, Anton, 2018, A new genus and two new species of cave-dwelling cyclopoids (Crustacea, Copepoda) from the epikarst zone of Thailand and up-to-date keys to genera and subgenera of the Bryocyclops and Microcyc, European Journal of Taxonomy 431, pp. 1-30: 4

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gen. nov.

Genus Siamcyclops  gen. nov. ADDE-C 2BC2A39FE95

Type species

Siamcyclops cavernicolus  gen. et sp. nov., by monotypy.


Small Cyclopidae  , with compact habitus and greatest width at posterior margin of cephalothorax. Antennule 11-segmented in female and 15-segmented in male. Genital double-somite wider than long, with obvious incision between anterior and posterior half of segment. Seminal receptacle small; anterior expansion slightly longer than posterior; anterior expansion wider than posterior one. Pd5 with lateral seta, vestige of baseoendopod of P5; two ventro-lateral setae on small knob. Anal operculum well developed; distal half of free margin serrated. Basis of antenna without seta representing Exp. Mandibular palp with three setae. Coxae of P1–P3 with seta on inner corner but absent on P4. P4 intercoxal sclerite with short obtuse prominence. P1–P4 with 2-segmented Exp and Endp, similar in length. Spine and setal formula on terminal segments of Exp P1–P4 as and, respectively. Male genital somite swollen, globular in shape. Apical spine and inner subterminal seta on male P3 Endp modified.


The genus is named after Siam, the ancient name for Thailand, prefixed to the existing generic name Cyclops  .


Details on the justification for erecting the new genus are given in the section ‘Differential diagnosis and remarks’ for Siamcyclops cavernicolus  gen. et sp. nov.