Gyorome, Komeda & Ohtsuka & Huys, 2024

Komeda, Sota, Ohtsuka, Susumu & Huys, Rony, 2024, A new genus and species of oceanic planktonic Tisbidae (Crustacea, Copepoda, Harpacticoida) with enlarged modified eyes, ZooKeys 1191, pp. 307-338 : 307

Genus Gyorome gen. nov.

Diagnosis.

Tisbidae . Body cyclopiform, large (> 1 mm); genital and first abdominal somites completely fused in ♀, forming genital double-somite. Sexual dimorphism in prosomal ornamentation, antennule, maxilliped, P2 endopod, P5, P6 and urosomal segmentation. Prosome capacious and vaulted; dorsal surface pustulate (covered by dense pattern of denticles); posterior margin of cephalothorax with middorsal protrusion in ♀, absent in ♂. Cephalic region with large, paired, modified eyes, each comprising a baculiform ocellus, a globular ( Gicklhorn’s?) organ and a semi-parabolic plate. Caudal ramus with seven setae and paired multi-branched tube-pores along posterior margin, displacing setae III-VI towards inner distal corner.

Antennule short, relatively compact and 8-segmented in ♀, with aesthetasc on segment 4; slender, 8-segmented and haplocer in ♂, with geniculation between segments 6 and 7, and aesthetasc on segment 4 and elongate digitiform segment 8. Antenna without seta on basis and proximal endopodal segment; exopod 4-segmented with armature [2, 1, 1, 3]. Mandible with unarmed basis and 1-segmented rami; exopod with one lateral and two terminal setae; endopod with two lateral and four terminal setae. Maxillule 3-segmented, comprising praecoxa, endopod, and compound segment representing fused coxa, basis and exopod. Maxilla 2-segmented, comprising syncoxa and allobasis; syncoxa with small coxal endite bearing one plumose seta; allobasis produced into curved claw with fine pinnules along outer margin and short plumose seta just over halfway claw length. Maxilliped ♀ 3-segmented, comprising short syncoxa articulating with subcylindrical pedestal, unarmed elongate basis, and small endopod with one unipinnate lateral seta and long, slender, distal claw accompanied at base by plumose seta. Maxilliped ♂ with modified basis (distal palmar margin produced into lobate spinular expansion) and endopod (with unguiform projection along medial margin).

P1-P4 with 3-segmented exopods and endopods; with dense pattern of minute spinules on anterior surface of protopod and rami. P1 outer spines on exp-2 and -3 without spinular combs; exp-2 not markedly longer than other exopodal segments. P1 endopod non-prehensile; indistinctly 3-segmented with transverse surface suture marking original segmentation between enp-2 and -3; enp-1 expanded in distal half forming lobate extension along medial margin; enp-3 small. P2 enp-1 inner seta modified in ♂, displaying pinnate ornamentation along distal half of outer margin (instead of plumose in ♀). Armature formula of P1-P4 as follows (Roman and Arabic numerals indicate spines and setae, respectively):

P5 2-segmented in both sexes, comprising baseoendopod and elongate exopod; obsolete endopodal lobe represented by one seta (minute in ♂); exopod with one outer, one inner and two terminal well developed setae. P6 with two minute setae in ♀; sixth pair of legs symmetrical in ♂, each with three well developed setae.

Type species.

Gyorome guttatum gen. et sp. nov. (by original designation).

Etymology.

The generic name is based on the Japanese word " Gyorome ", meaning "bulging eyes" and refers to the large ocelli in the cephalosome of the type species. Gender neuter.