Pseudodiaptomus greenwoodi, Uribe-Palomino & Walter, 2025

Pseudodiaptomus greenwoodi sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5

Type locality.

Australia, Queensland, Great Barrier Reef, Lizard Island   GoogleMaps , 14°40.45'S, 145°26.49'E, captured using light traps over coral reef.

Type specimens.

Holotype: ♂; USNM 1754446 About USNM GoogleMaps . Allotype: ♀; USNM 1754447 About USNM GoogleMaps . Paratypes: Australia • 10 ♀♀, • 10 ♂♂; Great Barrier Reef, Lizard Island ; Jan. 1978; M. S. Talbot; USNM 1754448 About USNM ; specimens intact; all types removed from original collection USNM 1110847 About USNM .

Additional material.

Australia • 2 ♂♂, 2 ♀♀; Great Barrier Reef ; Jul. 2000; A. D. McKinnon; USNM 310675 About USNM • 3 ♀♀; Queensland, Haughton River Estuary ; Sep 1992; A. D. McKinnon; USNM 310761 About USNM • 100 + specimens; Queensland, Great Barrier Reef, coral reef, Lizard Island ; Jan. 1977 – Jan. 1978; M. S. Talbot; USNM 1110845–1110847 About USNM ; captured using light traps over reefs .

Description.

Common features shared by females and males:

Antennule (Fig. 1 A, B View Figure 1 ) of females and left male antennule possessing 22 segments, segments 6 and 7 partly fused and counted separately, with modified barbed seta on segment 20.

Setal elements: (segment number = setae + aesthetasc [ae]) Female: 1 = 1 + ae, 2 = 2 + ae, 3 = 1 + ae, 4 = 2 + ae, 5 = 2 + ae, 6–7 = 2 + ae, 8 = 2 + ae, 9 = 1 + ae, 10 = 1 + ae, 11 = 1 + ae, 12 = 2 + ae, 13 = 1 + ae, 14 = 2 + ae, 15 = 2, 16 = 2, 17 = 2, 18 = 1, 19 = 2, 20 = 2 + ae, 21 = 2, 22 = 7. Male: 1 = 1 + ae, 2 = 1 + ae, 3 = 2 + ae, 4 = 1 + ae, 5 = 1 + ae, 6-7 = 2 + ae, 8 = 0 + ae, 9 = 1 + ae, 10 = 0 + ae, 11 = 1 + ae, 12 = 2 + ae, 13 = 2 + ae, 14 = 2 + ae, 15 = 2, 16 = 2, 17 = 1 + ae, 18 = 1, 19 = 1, 20 = 2 + ae, 21 = 2, 22 = 7.

Antenna (Fig. 2 A View Figure 2 ): coxa without seta, basis and first endopodal segment completely fuse with 1 seta each, endopodal segment 2 with 8 and 8 setae on terminal and subterminal lobes respectively; exopod 3 - segmented, first without seta, second with 1 proximal, 2 medial and 1 terminal setae; third with 3 medial and 4 terminal setae.

Mandible (Fig. 2 B View Figure 2 ): basis inner margin with 4 setae; endopod 2 - segmented, first with 4 setae, second with 6 setae; exopod 5 - segmented, first to fifth segments with 1, 1, 1, 1, 3 setae, respectively. Gnathobase with one long serrate dorsal seta and 3 cuspidate and 4 small, rounded teeth.

Maxillule (Fig. 2 C View Figure 2 ): praecoxal arthrite with 8 strong setae; coxa with 4 setae on endite and 9 on epipodite; basis with 4 and 5 setae on proximal and distal endites respectively; basal exite with 1 reduced seta; endopod 3 - segmented, with 4, 2 and 6 setae respectively; exopod with 8 setae along margin.

Maxilla (Fig. 2 D View Figure 2 ): praecoxa, coxa and basis partially fused and, exopodite quite reduced without visible segmentation. Praecoxal endites with 3 and 3 setae respectively; coxal endites with 2 setae each; basal endite with 2 setae and endopod with 7 setae.

Maxilliped (Fig. 2 E View Figure 2 ): praecoxa and coxa completely fused, endites with 0, 2, 3, 4 setae; basis with 3 setae; endopod 6 - segmented, with 1 seta on the first segment, second and third segments bearing 2 simple setae and 2 special robust mid-margin serrate setae; 1 seta on fourth and fifth segments and, 7 setae on sixth segment.

Legs 1–4 (not figured, as they are alike in shape and armature to figures published by Walter (1986), Srinui et al. (2013), and Nishida et al. (2024)), symmetrical and biramous with 3 - segmented rami; coxa and basis of both rami with spinules on distal corner. Seta and spine formula as follows:

Male (Figs 3 A – E View Figure 3 , 5 C, D View Figure 5 ).

Body length 1.11–1.12 mm ( n = 5); prosome length 2.4 times urosome. Cephalosome and first pedigerous somite separate and pedigerous somites 4 and 5 fused with distolateral acute projections. Urosome 5 - segmented, symmetrical, segments 2–4 posterodorsal margins with rows of acute spinule rows extending laterally. Caudal rami symmetrical, each ramus with 1 lateral, 4 terminal and 1 dorsal setae. Urosomites and caudal rami with proportions 12: 27: 14: 12: 14: 21 = 100.

Male right antennule (Fig. 1 C View Figure 1 ) 21 - segmented, segments 6 and 7 separate, geniculate at segment 18-19. Setal elements: 1 = 1 + ae, 2 = 1, 3 = 1 + ae, 4 = 2 + ae, 5 = 1, 6 = 2 + ae, 7 – 8 = 3 + ae, 9 = 1 + 2 ae, 10 = 0 + ae, 11 = 0 + ae, 12 = 1 + ae, 13 = 1 + ae, 14 = 2 + ae, 15 = 1 + ae, 16 = 2 + ae, 17 = 0, 18 = 1, 19 = 1 and medial spiniform projection, 20 = 2 + ae, 21 = 7.

Leg 5 (Fig. 3 D, E View Figure 3 ). Right leg: basis quadrate, with large plumose posterior-surface seta, anterior-surface sub-distal row of spinules, one small proximomedial knob-like process and a small digital medial endopod which is terminally pointed with short subterminal seta. Exopod 1 compressed, with distolateral large spiniform process, medial margin with large finger-like process terminally hirsute with fine spinules and terminal seta (visible in anterior view). Exopod 2 elongated and curved with a large distolateral spine reaching to midlength of exopod 3, medial margin with a groove lined with small spinules and a seta. Exopod 3 medially curved, tapering distally, medial margin with fine spinules and two proximal setae. Left leg: basis of similar size and shape to right leg basis with large lateral seta at mid-length, anterior-surface sub-distal row of spinules, and small distomedial endopod with terminal seta. Exopod 1 small quadrate with a large distolateral spine. Exopod 2 oval with a very large proximolateral spine, a small sub-lateral seta at mid-length, surrounded by fine spinules, terminates in a pair of short stout spines, the terminal spine larger, and 3 medial setae.

Female (Figs 4 A – D View Figure 4 , 5 A, B View Figure 5 ).

Body length, 1.33–1.39 mm ( n = 5). Prosome length 2.6 times urosome. Cephalosome and pedigerous somite 1 separate, pedigerous somites 4 and 5 completely fused with 2 symmetrical distally directed posterolateral spine-like projections and lined with fine spinules on each side of urosome insertion. Urosome 4 - segmented, genital double-somite slightly asymmetrical, swollen at midlength and ventrally, darker towards the swollen genital aperture with double row of proximal spinules, distally the genital aperture is covered with a 3 - lobed operculum, 2 lateral lobes thinner and expanded posteriorly, and a medial lobe triangulate tapering distally covering paired gonopores fused into a U-shaped structure. Urosomites 2 and 3 of similar size, lacking spinule rows on posterodorsal margins; somites 3 and 4 asymmetrical, right lateral margin reduced producing a curvature; somite 3 left posterolateral margin with small spinule patch. Caudal rami asymmetrical, right ramus mediolaterally curved and slightly thinner. Each ramus with typically 1 lateral, 4 terminal and a small dorsal setae. Medial margins of each ramus lined with fine setules. Urosomites 1–4 and caudal rami with proportions 34: 12: 12: 13: 29 = 100. The egg sac is single when present.

Leg 5 uniramous and slightly asymmetrical; basis slightly swollen medially, with a large plumose lateral seta on posterior surface. Exopods 3 - segmented, exopod 1 rectangular and 2 times longer than basipod, with distolateral spine. Exopod 2 distomedial corner produced and pointed with serrated hyaline process, left one slightly larger than the right, and short distolateral seta. Exopod 3 slender with serrate margins and a proximomedial spine. Endopods lacking.

Etymology.

The species is named in honour of Dr Jack Greenwood (University of Queensland), an Australian copepod taxonomist, who donated many Australian pseudodiaptomid samples over the years to the second author.

Distribution.

This species is currently known from the north of the Great Barrier Reef up to coastal waters of Townsville and surrounding areas.