Leucothoe serratissima, Myers, A. A., 2013

Myers, A. A., 2013, Amphipoda (Crustacea) from Palau, Micronesia: Families Dexaminidae, Eusiridae, Hyalidae, Ischyroceridae, Leucothoidae and Lysianassidae, Zootaxa 3731 (3), pp. 301-323 : 311-316

Leucothoe serratissima sp. nov.

( Figs 10 , 11 )

Type Material. Holotype male, 4.0 mm. (OUMNH.ZC.2002.24.103) Ngeritaal Pass, from Polycarpa captiosa (Sluiter) (Ascidiacea: Styelidae ), - 5 m depth; 07°19.223'N, 134°28.271'E; leg. S. De Grave & C. Burras, 20 May 2002.

Etymology. Referring to the serrated margins of coxae 1–4 the serrated basis of pereopods 5–7 and the serrated epimeron 2.

Description. Based on male holotype, 4.0 mm.

Head. Head truncate with acute eye lobe, eye subround. Antenna 1 and 2 subequal in length. Antenna 1 peduncular article 1 with strong posterodistal spine; peduncular article 2 longer than article 1; flagellum subequal with combined length of peduncular articles 2 and 3 with 6 articles. Antenna 2 peduncular article 4 stout, with two robust setae on the anteroproximal margin, peduncular article 5 shorter and more slender than peduncular article 4; flagellum shorter than peduncular article 5 with 4 articles.

Pereon. Gnathopod 1 coxa anterior and posterior margins concave, posterodistal margin strongly serrate; basis anterior margin with 3–4 short setae, posterior margin bare; ischium and merus bare; carpus with long posterodistal spine, distally strongly curved, anterodistal margin with weak nodules; propodus elongate, more than 5 × as long as broad, palm and posterodistal margin with nodules and with 6 facial setae distally; dactylus curved, more than one third length of propodus. Gnathopod 2 coxa sub-rectangular, anterior margin irregularly tuberculate, straight, posterior margin straight, posterodistal margin strongly serrate; basis anterior margin with five long setae; carpus spoon-shaped, more than half length of propodus, strongly setose, distal margin with 5 rounded lobes; propodus subovoid with long facial setae on distal third of inner face, palmar distal half with about 10 small rounded protrusions; dactylus curved, two thirds length of propodus. Pereopod 3 coxa subsquare, anterior and posterior margins very weakly convex, posterodistal margin serrate. Pereopod 4 coxa subtriangular, anterior margin straight, posterior margin scarcely excavate, posterodistal margin serrate. Pereopods 5–7 basis increasing in width from pereopod 5 to pereopod 7, posterior margins serrate.

Pleon. Epimeron 1 rounded. Epimeron 2 anterodistal margin produced into a rounded spine, posterodistal margin serrate. Epimeron 3 posterodistal margin with a weak knob. Uropod 1 rami subequal in length and subequal in length with peduncle. Uropod 2 outer ramus more than two thirds length of inner ramus, inner ramus longer than peduncle. Uropod 3 peduncle almost twice length of rami, rami subequal in length. Telson twice as long as broad, terminally tridentate.

Female. Unknown.

Remarks. This species is closest to L. serrata White and Thomas (2009) from the Great Barrier Reef of Australia. It differs from that species in the differing ornamentation of the male gnathopod 2 propodus palm. In L. serratissima , the crenulations are small, regular and confined to the distal end whereas in L. serrata , the crenulations are strong, irregular and cover half the palmar margin. In addition the dactylus of gnathopod 2 is

shorter and more strongly convex in L. serrata than in L. serratissima .

In L. serratissima , antenna 1 article 1 has a strong posterodistal spine, apparently lacking in L. serrata . Habitat. From ascidians.

Distribution. Known only from the type locality.

Figures

FIGURE 10. Leucothoe serratissima sp. nov., holotype male, Palau.

FIGURE 11. Leucothoe serratissima sp. nov., holotype male, Palau.