Koekotroides maene, J.-P & Myers & Shepherd, 2025

J. - P, Olivier, Myers, Alan A. & Shepherd, Lara D., 2025, A new genus and six new species of endemic landhopper in the family Arcitalitridae (Amphipoda: Talitroidea) from New Zealand, Zootaxa 5691 (2), pp. 277-311 : 294-296

Koekotroides maene sp. nov.

( Figs 11–12 )

Genus A sp. 6 ( Ball et al. 2024).

Type material. Holotype: female ( AMNZ184588 ), body length 6.0 mm, Tawhiti Rahi Island , Poor Knights, Northland, New Zealand, from leaf litter around rock outcrop on lower slopes, coll. Wise K.A.J., 10 December 1980. Allotype: male ( AMNZ184589 ), body length 5.5 mm, same data as holotype . Paratypes: 2 females ( AMNZ184590 ), body lengths 6.0 mm, same data as holotype ; 1 partially dissected female ( AMNZ184591 ), body length 6.0 mm, same data as holotype; 1 partially dissected female ( AMNZ184592 ), body length 5.5 mm, same data as holotype .

Etymology. The specific name is derived from the te reo Māori word for ‘smooth’, referring to the smooth posterior margins of epimera 2 and 3.

Description. Adult female 5.0– 6.5 mm.

Head. Antenna 1 extending to at least half of the way along peduncle article 5 of antenna 2; article 3 of peduncle longer than article 2; flagellum consisting of 3–4 articles. Antenna 2 article 4 length 2.3 times breadth; article 5, 1.5 times length of article 4; flagellum a little longer than peduncle, consisting of about 9–12 articles. Maxilliped compact, not splayed; endopodite apex rounded; exopodite distally arcuate with blunt apex; palp article 2 without distomedial lobe; article 4 small but distinct.

Pereon. Gnathopod 1 coxa sub-trapezoidal, anterior margin nearly straight; basis anterior margin weakly concave proximally; merus posterior margin without lobe covered in palmate setae; carpus elongate, posterior margin evenly convex, without lobe covered in palmate setae; propodus, about 0.6–0.7 times length of carpus, semi-elliptical, posterior margin with 4 long, straight or weakly curved, spear-like robust setae, palm oblique, simple. Gnathopod 2 slender, basis about 3.5–3.7 times as long as broad; merus produced posterodistally into a lobe covered in palmate setae; carpus and propodus short, stout, carpus posterior margin with lobe covered in palmate setae; propodus mitten-shaped in both sexes (femipod), subequal with or slightly longer than carpus, distal lobe apically rounded, covered in palmate setae; dactylus very short. Pereopod 3–4 parallel-sided in lateral view, anterior margin concave distally in frontal view; ischium short; merus long; carpus 0.5 times length of merus; propodus 1.5 times length of carpus. Pereopod 5 basis evenly narrowing distally, anterior and posterior margins convex proximally; merus subequal to carpus; propodus slightly longer than carpus. Pereopod 6 basis sub-elliptical, slightly narrower distally, margins convex; carpus subequal in length to merus; propodus approximately 1.3 times length of carpus. Pereopod 7 basis broadly obovate, nearly, as broad as long, posterior margin with distinct serrations each with a small seta; merus, carpus and propodus each progressively a little longer than the preceding article.

Pleon. Epimeron 1 shortest, posterior margin nearly straight; posteroventral corner with or without a small, subacute or rounded process. Epimeron 2 ventral margin weakly convex to nearly straight, deepest posteriorly; posteroventral corner nearly a right angle, with or without small, subacute or rounded process; posterior margin almost smooth, weakly convex to nearly straight. Epimeron 3 as deep as epimeron 2 at anteroventral corner; ventral margin very convex anteriorly, distinctly concave posteriorly; posterior margin almost smooth, convex. Pleopods 1–3 biramous, like those of K. tewhaarua . Uropod 1 peduncle slightly longer than the subequal rami, outer margin with 2 dorsal robust setae distally; distolateral robust seta approximately 0.5 x length of exopodite; exopodite without dorsal robust setae; endopodite with 2 dorsal robust setae. Uropod 2 peduncle subequal in length with endopodite; endopodite stouter though no longer than exopodite with 2 marginal robust setae; exopodite without marginal robust setae. Uropod 3 peduncle bulbous, with 1 very long lateral robust seta; ramus approximately 0.3 times length of peduncle, with 1 apical seta. Telson as broad as long, undulate, not incised apically, deep longitudinal furrow present ventrally, 1 large apical robust seta and 2 large dorsal robust setae on each side.

Habitat. Leaf litter underneath native vegetation.

Distribution. Poor Knights Islands (Tawhiti Rahi Island).

Remarks. Koekotroides maene sp. nov. is most closely related to K. tewhaarua sp. nov., but differs from it most obviously in the almost smooth posterior margins of epimera 2 and 3 (crenulate in K. tewhaarua sp. nov.).

Figures

FIGURE 11. Koekotroides maene sp. nov., female paratype (maxilliped, epimera 2–3, pereopod 7 basis, uropod 1, telson), Tawhiti Rahi Island, Poor Knights Islands. Scale bars a = maxilliped, telson; b = pereopod 7, epimera, uropod 1.

FIGURE 12. Koekotroides maene sp. nov., female paratype (gnathopods 1–2), Tawhiti Rahi Island, Poor Knights Islands.