Johnwellsia, Huys, Rony & Mu, Fanghong, 2021

Huys, Rony & Mu, Fanghong, 2021, Johnwellsia, a new intertidal genus of Parastenheliidae (Copepoda, Harpacticoida) from the Taiwan Strait, China, including a review of the family and key to genera, Zootaxa 5051 (1), pp. 236-318 : 240-241

Genus Johnwellsia gen. nov.

urn:lsid:zoobank.org:act:274AE5DF-1C04-448A-B0D3-7F7B38A6282D

Diagnosis. Parastenheliidae . Sexual dimorphism in antennule, P2–P3 endopods, P5–P6 and urosomal segmentation. Body fusiform; posterior margin of cephalothorax with plain hyaline frill; remaining somites (except P5-bearing somite and anal somite) with deeply divided, denticulodigitate, hyaline frills. Rostrum defined at base, large, reaching to halfway second segment of antennule; with parallel sides tapering sharply into pointed apex. Anal operculum semicircular, naked. Caudal ramus wider than long, without conspicuous spinular ornamentation; with seven setae, setae IV– V with fracture planes, not inflated at base in ♀ .

Antennule slender, segment 1 elongate in both sexes; 9-segmented in ♀, segments 7–9 shortest, with aesthetascs on segments 4 and 9; haplocer and indistinctly 11-segmented in ♂ (segment 4 largely incorporated in segment 5), with geniculation between segments 7 and 8, and aesthetascs on segments 5 and 11; segmental homologies in ♂: I, II– VIII, IX – XII, XIII, XIV – XVII, XVIII, XIX – XX, XXI – XXII, XXIII, XXIV – XXV, XXVI – XXVIII. Antenna not sexually dimorphic; with completely fused allobasis lacking endopodal pinnate seta on abexopodal margin; exopod 2-segmented, proximal segment with two setae, distal segment with one lateral and three apical elements; free endopod without penicillate elements. Mandible with three elements on basis; endopod with two lateral and four apical setae; exopod rudimentary, represented by single seta on minute protuberance. Maxillulary coxal epipodite represented by one seta. Maxilla with three endites on syncoxa; endopod not completely discrete at base, with two setae. Maxilliped with two setae on syncoxa; basis with two setae, without longitudinal spinular row on palmar margin; endopod represented by claw with three accessory setae .

P1 inner basal spine not sexually dimorphic. P1 exopod 3-segmented, segments subequal in length; exp-2 with inner seta; exp-3 with two pinnate spines, one geniculate seta and one non-geniculate bipinnate seta. P1 endopod 2-segmented; enp-1 longer than exopod, with long, proximally inserted, pinnate inner seta, not extending to distal margin of segment, segment margins without area of reduced chitinization; enp-2 with one naked minute seta and two naked claws of different lengths. P2–P4 rami 3-segmented; inner seta of P2–P4 exp-1 of moderate size; distal inner seta of P3–P4 exp-3 reduced. P2 endopod ♂ 2-segmented; compound enp-2 with one inner seta (inner seta of ancestral enp-3 lost). P3 endopod ♂ 3-segmented; without inner seta (vs two in ♀) on enp-3, resulting in 1.1.021 pattern; outer spine not transformed into spinous apophysis. Armature formula of P2–P4 as follows:

P 5 ♀ endopodal lobe with five setae, outermost minute; inner margin without transverse striae; exopod moderately elongate, articulation with baseoendopod very narrow, with six elements. P 5 ♂ endopodal lobe with two small elements, outer one shortest; exopod 2-segmented; exp-1 with short outer seta, exp-2 with three elements. Vestigial P 6 ♀ represented by three setae. P 6 ♂ with three setae.

Type and only species. Johnwellsia bipartita sp. nov. (by original designation herein).

Etymology. The genus is named in dedication to the late Prof. John J.B. Wells, in honour of his outstanding career in harpacticoid taxonomy, systematics and biogeography.