Research Article 
Corresponding author: Koraon Wongkamhaeng ( koraon@gmail.com ) Academic editor: Charles Oliver Coleman
© 2016 Koraon Wongkamhaeng, Pongrat Dumrongrojwattana, Manasawan Saengsakda Pattaratumrong.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Wongkamhaeng K, Dumrongrojwattana P, Saengsakda Pattaratumrong MS (2016) Two new species of Floresorchestia (Crustacea, Amphipoda, Talitridae) in Thailand. ZooKeys 635: 3151. https://doi.org/10.3897/zookeys.635.10454

The beachhopper and landhopper genus Floresorchestia Bousfield, 1984 is most widespread in terrestrial and marine littoral habitats and has been recorded from the South African coasts through to tropical IndoPacific and Caribbean Sea. In Thailand, there is only Floresorchestia samroiyodensis Azman, Wongkamhaeng & Dumrongrojwattana, 2014 reported from the swamp of Prachuab Kiri Khan, southern Thailand. In this work, two new species of Floresorchestia from Phutsa Reservoir in Nakhon Ratchasima and the manmade swamp in Burapha University are described. The new species are characterised by the mandible left lacinia mobilis 4dentate; the posterior margin of merus, carpus and propodus covered in palmate setae; the uropod 3 peduncle with two robust setae and the telson longer than broad. The characters of the specimens are described and illustrated in this paper. All specimens are deposited in the Princess Maha Chakri Sirindhorn Natural History Museum, Prince of Songkla University, Thailand.
Amphipoda, Crustacean, Floresorchestia, new species, Talitridae, Thailand
The talitrid amphipod genus Floresorchestia Bousfield, 1984 is most widespread in littoral and terrestrial habitats. They have been recorded from the South African coast through to tropical Indo Pacific and Caribbean Sea. The amphipod can be recognised from the number of stridulating organs above the ventral margin (epimera 1–3, 2 or 2–3). Members of this genus occupy a variety of habitat such as beach (beachhoppers) or land (landhoppers) or stream (streamhoppers) (
In Southeast Asia, thirteen species of Floresorchestia have been recorded. There are both supralittoral (seven species) and terrestrial groups (six species). The supralittoral species have been reported from the Gulf of Thailand (Floresorchestia sp. 3), (
This study is based upon material collected from leaf litter of Phutsa Reservoir in Nakhon Ratchasima, northeastern Thailand and a manmade swamp in Burapha University, eastern Thailand in March and April 2016 respectively. Samples were collected using handnets and were then carefully transferred into plastic containers and fixed in 10% buffered formalin. In the laboratory, amphipod specimens were sorted out and stored in 70% alcohol. The animals were then examined under a compound microscope and later selected for dissection. The appendages of the dissected specimens were examined and figures were produced using camera lucida attached to an Olympus CH30 light microscope. The pencil drawings were scanned and digitally inked using a WACOM bamboo CTH970 graphics board following the method described in
A antenna
G gnathopod
HD head
LL lower lip
MD mandible
MX maxilla
MP maxilliped
P pereopod
Pl pleopod
T telson
U uropod
UR urosome
UL upper lip
R right
L eft
♂ male
♀ female
Type material has been deposited at Prince of Songkla University Zoological Collection (
Orchestia floresiana
Floresorchestia ancheidos (K.H. Barnard, 1916); Floresorchestia andrevo Lowry & Springthorpe, 2015; Floresorchestia anomala (Chevreux, 1901); Floresorchestia anoquesana (Bousfield, 1971); Floresorchestia anpingensis Miyamoto & Morino, 2008; Floresorchestia australis Lowry & Springthorpe, 2009b; Floresorchestia floresiana (Weber, 1892); Floresorchestia guadalupensis Ciavatti, 1989; Floresorchestia hanoiensis Hou & Li, 2003; Floresorchestia kalili Lowry & Springthorpe, 2015; Floresorchestia laurenae Lowry & Springthorpe, 2015; Floresorchestia malayensis (Tattersall,1922); Floresorchestia monospina (Stephensen, 1935); Floresorchestia oluanpi Lowry & Springthorpe, 2015; Floresorchestia palau Lowry & Myers, 2013b; Floresorchestia papeari Lowry & Springthorpe, 2015; Floresorchestia pectenispina (Bousfield, 1970); Floresorchestia pohnpei Lowry & Myers, 2013b; Floresorchestia poorei Lowry & Springthorpe, 2009a; Floresorchestia samoana (Bousfield, 1971); Floresorchestia samroiyodensis Azman, Wongkamhaeng & Dumrongrojwattana, 2014; Floresorchestia seringat Lowry & Springthorpe, 2015; Floresorchestia thienemanni (Schellenberg, 1931); Floresorchestia vitilevana (J.L. Barnard, 1960); Floresorchestia vugiaensis (Dang & Le, 2011); Floresorchestia yap Lowry & Springthorpe, 2015; Floresorchestia yehyuensis Miyamoto & Morino, 2008.
1  Male gnathopod 1: posterior margin of carpus and propodus each with a lobe covered in palmate seta; uropod 3 peduncle with three robust setae  F. samroiyodensis 
–  Male gnathopod 1 posterior margin of merus, carpus and propodus each with a lobe covered in palmate seta; uropod 3 peduncle with two robust setae  2 
2  Gnathopod 2 extending between 31–35% along the posterior margin; uropod 1 peduncle with 46 robust setae; uropod 3 ramus without marginal robust setae; telson apically incised with four robust setae per lobe  F. boonyanusithii sp. n. 
–  Gnathopod 2 reaching between 36–40% along posterior margin; uropod 1 peduncle with more than six robust setae; uropod 3 ramus with a marginal robust seta; telson apically incised with five robust setae per lobe  F. buraphana sp. n. 
Holotype. ♂, THAILAND, Northeastern Thailand, Phutsa Reservoir, Nakhon Ratchasima (15°2'59"N, 102°2'18"E), 21 Febuary 2016, Boonyanusith, C.
Named after Chaichat Boonyanusith in appreciation of his contribution to the terrestrial amphipod study in Thailand.
Landhoppers (truly terrestrial). Size 5.5 mm. Sexual dimorphism present.
Based on male, holotype, 5.5 mm,
Head. Eye large (1/2 head length). Antenna 1 short, having four short articles of flagellum, extending one quarter (¼) of 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 4dentate, lacinia mobilis 4dentate, molar strong. Maxilla 1 inner plate slender with two terminal setae; outer plate with nine terminal serrate setae with small palp, 1articulate. 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, buttonshaped.
Pereon. Gnathopod 1 sexually dimorphic; subchelate; coxa 1 smaller than coxa 2, ventral margin with six setae; posterior margin of merus, carpus and propodus each with a lobe covered in palmate setae, palmate lobes in male only; carpus 1.4 times as long as propodus, 2.6 times as long as broad; propodus subtriangular with welldeveloped posterodistal lobe, anterior margin with two groups of robust setae, posterior margin with four robust setae, palm with seven 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 midanterior margin; carpus triangular, reduced (enclosed by merus and propodus) without posterior lobe; propodus subovate, 1.5 times as long as wide; palm acute, extending 33% along posterior margin, lined with robust setae; dactylus longer than palm, attenuated distally, posterior margin smooth.
Pereopods 3–7 cuspidactylate. Pereopod 3 coxa subquadrate 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 the posterior margin. Pereopod 5 coxa bilobed, anterior lobe slightly larger than the posterior lobe; propodus distinctly longer than the carpus. Pereopods 6–7; pereopod 6 subequal in length to pereopod 7; coxa posterior lobe inner view posteroventral corner rounded, posterior margin perpendicular to ventral margin; coxal gill convoluted; 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 not longer than outer ramus, shorter than peduncle; inner ramus with seven articles; outer ramus with seven 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 ten articles; outer ramus with eight articles.
Epimera 1–3 vertical slits present on plate 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 four robust setae, distolateral robust seta absent; inner ramus subequal in length to outer ramus, inner ramus with marginal robust setae (one row), with four marginal robust setae; outer ramus without marginal robust setae. Uropod 2 not sexually dimorphic; peduncle with three 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, 1.75 times as long as broad, ramus linear with three apical setae.
Telson longer than broad, apically cleft, dorsal midline half of the telson, with marginal and apical robust setae, four 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 mittenshaped; posterior margin of carpus and propodus each with lobe covered in palmate setae; carpus well developed, posterior lobe projecting between merus and propodus; nearly twice as long as wide; palm obtuse, not lined with robust setae, posterodistal corner without spine; dactylus subequal in length to palm, not modified distally, blunt.
Terrestrial, most prefer living in Typha angustifolia root near reservoir.
Northeastern Thailand.
Floresorchestia boonyanusithii sp. n. is the second landhopper reported in Thailand. It can be distinguished from F. samroiyodensis by the characters in the above key. Additionally, this species shows the following differences: 1) the left mandible lacinia mobilis has four cusps in both male and female (vs. male 4dentate and female 6dentate); 2) male gnathopod 1 carpus is 2.6 times longer than broad, 1.4 as long as propodus (vs. 2 times longer than broad, 1.8 times as long as propodus); 3) male gnathopod 2 propodus 1.4 times longer than broad, palm extending 39% along posterior margin (propodus 1.8 times longer than broad, palm extending 27% along posterior margin); 4) pereopod 7 is shallow, broadly rounded (vs. rounded, produced downwards almost to merus).
Floresorchestia boonyanusithii is characterised by a mandible left lacinia mobilis 4dentate and uropod 3 peduncle with two robust setae. The only similar species are F. buraphana sp. n. and F. hanoiensis Hou & Li, 2003. The new species differs from F. hanoiensis Hou & Li, 2003 in its pereopod 4 is thickened proximally with a notch midway along its posterior margin (vs. pereopod 4 similar to pereopod 3 dactylus) pereopod 7 basis shallow, broadly rounded (vs. produced downwards almost to merus); pleopod 13 peduncle without marginal robust setae; epimera 3 posterior margin without setae with 20 slits (vs epimera 3 posterior margin with five slits) and telson apically incised with four robust setae per lobe (vs. three robust setae per lobe).
Floresorchestia boonyanusithii shared several characters with F. buraphana in having a mandible left lacinia mobilis 4dentate; posterior margin of merus, carpus and propodus covered in palmate setae; uropod 3 peduncle with two robust setae and telson is longer than broad. F. boonyanusithii differs from F. buraphana in having uropod 3 rami without marginal setae (vs rami with one marginal seta) and telson with four robust setae per lobe (vs. five robust setae per lobe).
Floresorchestia boonyanusithii sp. n. holotype, male, 5.5 mm (
Floresorchestia boonyanusithii sp. n. holotype, male, 5.5 mm (
Floresorchestia boonyanusithii sp. n. holotype, male, 5.5 mm (
Floresorchestia boonyanusithii sp. n. holotype, male, 5.5 mm (
Holotype. ♂, THAILAND, Eastern Thailand, Manmade swamp in Burapha University, Chonburi (13°16'37"N, 100°55'21"E), 21 April 2016, Damrongrojwattana, P.
Named for Burapha University where the manmade swamp is the type locality of the species.
Supralittoral (325 m from the Bang San Beach). Size 6.3 mm. Sexual dimorphism present.
Based on male, holotype, 6.3 mm,
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 5dentate, lacinia mobilis 5dentate, molar strong. Maxilla 1 inner plate slender with two terminal setae; outer plate with nine serrate robust setae and with small palp, 1articulate. 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, buttonshaped.
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 subtriangular with welldeveloped 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 midanterior 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 mittenshaped; 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.
Fresh water swamps in Burapha University.
Eastern Thailand.
The characters of Floresorchestia buraphana sp. n. that separate it from F. samroiyodensis
F. buraphana sp. n. appears to be closely related to F. yehyuensis, sandhopper from Taiwan in having; 1) a mandible left lacinia mobilis 4dentate; 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 F. yehyensis), uropod 3 peduncle with three robust setae (with two robust setae in F. yehyensis), epimera 2 with 25 slits (33 slits in F. yehyensis) and telson longer than broad with dorsal midline half way (telson is broader than its length without dorsal midline in F. yehyensis).
Floresorchestia buraphana sp. n. holotype, male, 6.3 mm (
Floresorchestia buraphana sp. n. holotype, male, 6.3 mm (
Floresorchestia buraphana sp. n. holotype, male, 6.3 mm (
Floresorchestia buraphana sp. n. holotype, male, 6.3 mm (
Floresorchestia buraphana sp. n. allotype, female 8.8 mm (
A summary of the diagnostic characteristics that serve to distinguish closely related Floresorchestia species.
Species  Body length (mm)  Left mandible lacinia mobilis  Gnathopod 1  Gnathopod 1 carpus  Pleopod 1–3 peduncle  Slit on epimera 2 and 3  Uropod 1 peduncle  Uropod 3 peduncle  Telson 

F. boonyanusithii sp. n.  5.5  4dentate  Posterior margin of merus, carpus and propodus each with lobe covered in palmate setae  2.6 × as long as broad, palm extending 33% along posterior margin  Without marginal setae  27 and 20 slits  With 6 robust setae  Peduncle with 2 robust setae, rami 1.8 as long as broad without marginal setae  Dorsal midline at least halfway with 4 setae per lobe 
F. buraphana sp. n.  6.3  4dentate  Posterior margin of merus, carpus and propodus each with lobe covered in palmate setae  2 × as long as broad, palm extending 37% along posterior margin  Without marginal setae  25 and 15 slits  With 9 robust setae  Peduncle with 2 robust setae, rami 2.2 x as long as broad with a marginal seta  Dorsal midline at least halfway with 5 setae per lobe 
F. hanoiensis Hou & Li, 2003  6.5  4dentate  Posterior margin of merus, carpus and propodus each with lobe covered in palmate setae  1.9 × as long as broad, palm extending between 4650% along posterior margin  With marginal robust setae  22 and 5 slits  With 8 robust setae  Peduncle with 2 robust setae, rami 1.8 as long as broad without marginal setae  Dorsal midline entire with 3 setae per lobe 
F. samroiyodensis Azman, Wongkamhaeng & Dumrongrojwattana, 2014  10.5  Male 4dentate, female 6dentate  Posterior margin of carpus and propodus each with lobe covered in palmate setae  2 × as long as broad, palm extending 27% along posterior margin  Without marginal setae  21 and 13 slits  With 6 robust setae  Peduncle with 2 robust setae, rami 1.9 as long as broad with a marginal seta  Dorsal midline vestigial or absent with 5 setae per lobe 
The authors would like to thank Dr. Chaichat Boonyanusith for providing specimens for study and being a source of inspiration for this work. We gratefully acknowledge Dr. Charles Oliver Coleman from the Museum of für Naturkunde in Berlin, Germany and Dr. Jim Lowry from the Australian Museum in Sydney for their assistance with the literature. This work was partially financial supported by Research Grant of Burapha University through National Research Council of Thailand (Grant no. 6/2559).