Systematics and phylogeny of Cristacoxidae (Copepoda, Harpacticoida): a review Author Huys, Rony Author Kihara, Terue Cristina text Zootaxa 2010 2568 1 38 journal article 10.5281/zenodo.197323 c12b1ab5-b39a-4b92-a548-11e0352d1cad 1175-5326 197323 Genus Acuticoxa gen. nov. Diagnosis. Nannopodidae . Body cylindrical; slightly depressed dorsoventrally; somites with finely incised hyaline frills and dense setular surface ornamentation; genital double-somite Ƥ completely fused. Rostrum prominent, triangular. Anal operculum moderately developed, spinulose. Caudal ramus long and rectangular; with 7 setae; seta V longest, typically composed of swollen proximal and setular distal part. Antennule without spinous processes; 4-segmented in female; segment I elongate, segments III–IV oriented posteriorly and with aesthetasc. Antenna with abexopodal seta on allobasis; exopod absent or represented by minute unisetose segment; endopod with 6 distal (3 geniculate and 3 simple) and 2 medial elements. Mandible biramous with unisetose exopod fused to basis and 1-segmented trisetose endopod; basis with 2 setae. Maxillule with 2 elements on coxal endite; basal endites represented by 2 and 3 setae, respectively; endopod incorporated into basis and represented by 2 setae; exopod absent. Maxillary syncoxa with 2 endites bearing 2 and 3 elements, respectively; allobasis with claw and 1 accompanying seta; endopod represented by 2 setae. Maxillipedal syncoxa and basis unarmed; endopod 1-segmented with long geniculate claw and typically 1 accompanying seta. P1 with strong unguiform outer spinous process on coxa; basis with inner and outer seta; exopod 2- segmented, exp-1 with or without outer seta, exp-2 with 5 setae; endopod prehensile, enp-1 without inner seta, enp-2 with 1 claw and 1 basally reinforced seta. P2–P4 with outer spinous projection on coxa; P2–P3 exopods 1- ( A. ubatubaensis ) or 2-segmented ( A. biarticulata ); P4 exopod 1-segmented; P2–P4 endopods 1-segmented with single apical element. Spine and setal formula as follows:

Exopod	Endopod
P1	0.023	0.020
P2	0.022 or 0 23	0 10
P3	0.022 or 0 23	0 10
P4	0 23	0 10

P5 exopod and baseoendopod fused in Ƥ, forming single plate with 8 setae/spines; intercoxal sclerite discernible. Genital field Ƥ with large median copulatory pore; P6 represented by 2 short setae. Type species: Acuticoxa ubatubaensis gen. et sp. nov. Other species: Laophontisochra sp. sensu George (2002) [= Acuticoxa biarticulata sp. nov. ] Etymology. The generic name is derived from the Latin adjective acutus , meaning pointed, sharp, and the Latin noun coxa , meaning hip, and refers to the pointed projection found on the coxae of at least legs 2–4. Gender feminine.