Floresorchestia buraphana, Wongkamhaeng, Koraon, Dumrongrojwattana, Pongrat & Pattaratumrong, Manasawan Saengsakda, 2016

Wongkamhaeng, Koraon, Dumrongrojwattana, Pongrat & Pattaratumrong, Manasawan Saengsakda, 2016, Two new species of Floresorchestia (Crustacea, Amphipoda, Talitridae) in Thailand, ZooKeys 635, pp. 31-51 : 35-37

Floresorchestia buraphana sp. n. Figures 6, 7, 8, 9, 10, Table 1

Type material.

Holotype. ♂, THAILAND, Eastern Thailand, Man-made swamp in Burapha University, Chonburi (13°16'37"N, 100°55'21"E), 21 April 2016, Damrongrojwattana, P. PSUZC-CR-0312. Allotypes, ♀ collected with holotype; PSUZC-CR-0313; Paratype, collected with holotype (PSUZC-CR-0314 (5♂; 5♀))

Etymology.

Named for Burapha University where the man-made swamp is the type locality of the species.

Ecological type.

Supralittoral (325 m from the Bang San Beach). Size 6.3 mm. Sexual dimorphism present.

Description.

Based on male, holotype, 6.3 mm, PSUZC-CR 0312.

Head.Eye large (one third of head length). Antenna 1 short, having five articles of flagellum, extending one quarter ( ¼) of antenna 2 peduncle article 5. Antenna 2 peduncular articles slender; article 5 longer than article 4; flagellum of 13 articles, longer than peduncle, final article minute, without apical cluster of serrate setae. Upper lip broad, deep, apex rounded. Lower lip without inner plates. Left mandible incisor 5-dentate, lacinia mobilis 5-dentate, molar strong. Maxilla 1 inner plate slender with two terminal setae; outer plate with nine serrate robust setae and with small palp, 1-articulate. Maxilliped inner plate with apical and subapical plumose setae and three large conical robust setae; outer plate with two rows of subapical setae; palp article 2 distomedial lobe well developed; article 4 reduced, button-shaped.

Pereon.Gnathopod 1 sexually dimorphic; subchelate; coxa 1 smaller than coxa 2, ventral margin with five setae; posterior margin of merus, carpus and propodus each with lobe covered in palmate setae, palmate lobes in male only; carpus 1.5 times as long as propodus, twice as long as broad; propodus sub-triangular with well-developed posterodistal lobe, anterior margin with two groups of robust setae, posterior margin with five robust setae, palm with five robust setae; dactylus cuspidactylate, subequal in length to palm. Gnathopod 2 sexually dimorphic; subchelate; basis anterior margin smooth, widened distally; ischium with rounded lobe on mid-anterior margin; carpus triangular, reduced (enclosed by merus and propodus) without posterior lobe; propodus subovate, 1.5 times as long as wide; palm acute, extending 37% along posterior margin, lined with robust setae; dactylus longer than palm, attenuated distally, posterior margin smooth.

Pereopods 3-7 cuspidactylate. Pereopod 3 coxa subquadrat with posterior process, merus longer than carpus, distally expanded; propodus slender, longer than carpus. Pereopod 4 slightly shorter than pereopod 3; coxa wider than long with posterior process; carpus significantly shorter than carpus of pereopod 3; dactylus thickened proximally with a notch midway along posterior margin. Pereopod 5 coxa bilobed, anterior lobe larger than posterior lobe; propodus distinctly longer than carpus. Pereopod 6 subequal in length to pereopod 7; coxa posterior lobe inner view - posteroventral corner rounded, posterior margin perpendicular to ventral margin; coxal gill simple; propodus slender, longest; dactylus narrow. Pereopod 7 basis lateral sulcus absent, posterior margin with distinct minute serrations, each with a small seta, posterodistal lobe present, shallow, broadly rounded; merus and carpus distally expanded; carpus subrectangular, propodus slender, longest; dactylus short.

Pleon.Pleopods all well developed. Pleopod 1 peduncle without marginal setae; biramous, inner ramus subequal to outer ramus, shorter than peduncle; inner ramus with nine articles; outer ramus with nine articles. Pleopod 2 peduncle without marginal setae; biramous, inner ramus subequal to outer, shorter than peduncle; inner ramus with eight articles; outer ramus with eight articles. Pleopod 3 peduncle without marginal setae; biramous, outer ramus shorter than peduncle; inner ramus with eight articles; outer ramus with eleven articles.

Epimera 1-3 vertical slits present on plates 2 and 3. Epimera 2 with 27 slits. Epimera 3 with 20 slits. Epimeron 2 subequal in length to epimeron 3. Epimeron 3 posterior margin smooth, without setae, posteroventral corner with small subacute tooth, ventral margin without robust setae.

Uropod 1 peduncle with nine robust setae, distolateral robust seta absent; inner ramus subequal in length to outer ramus, inner ramus with marginal robust setae (one row), with three marginal robust setae; outer ramus without marginal robust setae. Uropod 2 not sexually dimorphic; peduncle with four robust setae; inner ramus subequal in length to outer ramus, with marginal robust setae; outer ramus with marginal robust setae in one row, outer ramus with two marginal robust setae. Uropod 3 peduncle with two robust setae; ramus not fused to peduncle; ramus shorter than peduncle, 2.2 times as long as broad, ramus linear with a marginal seta and three apical setae.

Telson longer than broad, apically cleft, dorsal midline half of the telson, with marginal and apical robust setae, five setae per lobe.

Female (sexually dimorphic characters).Gnathopod 1 coxa anterior margin straight; merus lacking tumescent lobe, posterior margin with five robust setae; propodus without tumescent protuberance, anterior margin with two groups of robust setae; palm slightly acute, dactylus inner lateral posterior margin with one robust seta.

Gnathopod 2 mitten-shaped; posterior margin of carpus and propodus each with a lobe covered in palmate setae; carpus well developed, posterior lobe projecting between merus and propodus; nearly twice as long as its width; palm obtuse, not lined with robust setae, posterodistal corner without spine; dactylus subequal in length to palm, not modified distally, blunt.

Habitat.

Fresh water swamps in Burapha University.

Distribution.

Eastern Thailand.

Remarks.

The characters of Floresorchestia buraphana sp. n. that separate it from Floresorchestia samroiyodensis Azman et al. 2014 and Floresorchestia boonyanusithii sp. n. have been given in the above key. Additionally, this species shows the following features: 1) uropod 1 peduncle with nine robust setae; 2) uropod 3 peduncle with two robust setae and rami with three apical setae and telson longer than broad, dorsal midline at least halfway, apically incised with five robust setae per lobe.

Floresorchestia buraphana sp. n. appears to be closely related to Floresorchestia yehyuensis , sand-hopper from Taiwan in having; 1) a mandible left lacinia mobilis 4-dentate; 2) gnathopod 1 merus, carpus and propodus each with palmate lobe and 3) uropod 3 ramus with one marginal setae. It differs however in the pereopod 4 dactylus which is thickened proximally with a notch midway along the posterior margin (similar to pereopod 3 dactylus in Floresorchestia yehyensis ), uropod 3 peduncle with three robust setae (with two robust setae in Floresorchestia yehyensis ), epimera 2 with 25 slits (33 slits in Floresorchestia yehyensis ) and telson longer than broad with dorsal midline half way (telson is broader than its length without dorsal midline in Floresorchestia yehyensis ).