Ledoyerella kunensis, Zettler & Myers, 2018

Zettler, Michael L. & Myers, Alan, 2018, A new species of Ledoyerella, L. kunensis sp. nov. (Amphipoda, Senticaudata, Kamakidae) from South West Africa, Zootaxa 4450 (1), pp. 142-150 : 143-149

Ledoyerella kunensis sp. nov.

( Figs 1–5 )

Type material. Holotype: one male, 6.7 mm ( ZMB 31313) (Stn. BE 2; Namibia, Skeleton Coast ; water depth 32 m; grab sampling; 18.191°S; 11.841°E; salinity at bottom 35.4 psu, temperature at bottom 14.3°C, oxygen 1.46 ml/l, collected 12 May 2004) . Paratype: one female, 5.5 mm ( ZMB 31314) (data same as holotype) . Non-type material ( ZMB 31315) (Stn. BE 1; Namibia, Skeleton Coast; water depth 42 m; grab sampling; 18.385°S; 11.922°E; salinity

at bottom 35.3 psu, temperature at bottom 13.4°C, oxygen 0.12 ml/l, collected 12 May 2004). Additional material, see Table 1.

Type locality. Namibia (Province Kunene) about 100 km south of the River Kunene mouth, off the Skeleton Coast in 32 m water depth.

Etymology. Named for the River Kunene at the border between Angola and Namibia in the waters off which the material was collected.

Description. Based on male holotype, 6.7 mm.

Head, Head ocular lobes extended forward; eye oval, of medium size, almost entirely situated in the ocular lobe; anteroventral margin deeply excavated. Antenna 1 scarcely more than one third body length; peduncular articles 1–3 in the length ratios 1:1:0.6; flagellum about two thirds length of peduncle with 12 articles; accessory flagellum with two long articles and a rudimentary terminal article. Antenna 2 longer than antenna 1; peduncular articles 4 and 5 subequal in length; flagellum only a little longer than the combined length of peduncular articles 4 and 5, with 19 articles. Labrum without epistome. Mandible molar of moderate size, triturative; left lacinia mobilis 4-dentate, right lacinia mobilis 3-dentate; palp article 2 longer than article 3; article 3 subovate with long mostly distal and subdistal setae. Maxilla 1 inner plate with two unequal distal setae and many fine setae along medial margin. Maxilla 2 lacking oblique setal row. Labium mandibular projections blunt. Maxilliped palp article 2 about twice as long as broad, article 4 about two thirds length of article 3.

Pereon. Sternal processes absent. Gnathopod 1 coxa anteriorly produced, rounded; basis immensely swollen, posterodistal margin with three groups of long setae; carpus enlarged, subovoid, two thirds as broad as long; propodus about two thirds length of carpus, the posterior margin weakly crenulate, palm produced forward anterodistally into rounded lobe; dactylus stout, posterior margin with spines, overlapping palm. Gnathopod 2 coxa larger than that of gnathopod 1, deeper than broad, a little less deep that coxa 3; basis immensely swollen, anterior margin weakly concave distally; carpus parallel-sided; propodus about two thirds length of carpus, posterodistal margin produced into stout, parallel-sided round ending projection; palm irregular with shallow sinus, and thick, distally rounded, subproximal robust seta; dactylus stout, overlapping palm. Pereopods 3–4 slender, dactylus about half length of propodus. Pereopods 5–7 in the length ratios 1:1.4:1.7; basis only weakly expanded.

Pleon. Epimeral plates 1–3 rounded. Uropod 1 peduncle longer than rami with strong distal inter-ramal spine; inner ramus longer than outer. Uropod 2 peduncle subequal in length with outer ramus, inner ramus longer than outer. Uropod 3 rami longer than peduncle, outer ramus with small second article, both rami with distal robust setae, lacking slender setae. Telson with each lobe bearing a strong robust seta.

Female (sexually dimorphic characters). Gnathopod 1 slender; basis parallel-sided, nearly three times as long as broad; carpus longer than propodus; propodus palm very oblique, with subproximal robust seta; dactylus fitting palm. Gnathopod 2 basis slender, parallel-sided about twice as long as broad; carpus and propodus stout, subequal in length, palm oblique, with subproximal robust seta; dactylus slightly overlapping palm.

Habitat. This new species occurred in water depths between 19 and 204 m on sandy and muddy sediments often with shell debris. The salinity ranged between 35.3 and 35.7 psu, the oxygen content in bottom water varied between 0.12 and 2.3 ml/l. The co-occurring temperatures were between 13 and 17°C.

Distribution. Currently known only from the coasts of Angola and Namibia.

Remarks. Ledoyerella kunensis sp. nov. is most similar to L. caputphotis , but differs in the form of the male gnathopods. In L. kunensis sp. nov. gnathopod 1 has a short propodus with palmar lobe, whereas in L. caputphotis the propodus is long, with an oblique palm. The gnathopod 2 has a slender propodus with strong forward projecting palmar spine in L. kunensis sp. nov., whereas in L. caputphotis the propodus is broad, with a weak, short palmar spine. In L kunensi s sp. nov., antenna 1 is shorter than antenna 2 (longer than antenna 2 in L. caputphotis ), In addition the uropod 2 peduncle of L. caputphotis bears a long distal inter-ramal spine, lacking in L. kunensis sp. nov. and L. caputphotis has long slender terminal setae on the outer ramus of uropod 3 that are absent in L. kunensis sp. nov.

Figures

FIGURE 1. Ledoyerella kunensis sp. nov., lateral view of holotype male (6.7 mm).

FIGURE 2. Ledoyerella kunensis sp. nov., antennae and mouthparts of holotype male.

FIGURE 3. Ledoyerella kunensis sp. nov., gnathopods, coxal plates, epimeral plates and pereopods 3 and 4 of holotype male.

FIGURE 4. Ledoyerella kunensis sp. nov., pereopods 5 to 7, uropods and telson of holotype male.

FIGURE 5. Ledoyerella kunensis sp. nov., gnathopods and pereopod 3 of paratype female (5.5 mm).