Thailandorchestia rhizophila, Wongkamhaeng & Dumrongrojwattana & Sumitrakij & Keetapithchayakul, 2022
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publication ID |
https://dx.doi.org/10.3897/zookeys.1099.82949 |
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publication LSID |
lsid:zoobank.org:pub:7F832E2C-76D9-4CC9-BD40-0E074B0D37BB |
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persistent identifier |
https://treatment.plazi.org/id/BDA296BD-ED94-4AEA-AF3E-B6894581D459 |
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taxon LSID |
lsid:zoobank.org:act:BDA296BD-ED94-4AEA-AF3E-B6894581D459 |
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treatment provided by |
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scientific name |
Thailandorchestia rhizophila |
| status |
sp. nov. |
Thailandorchestia rhizophila sp. nov.
Diagnosis.
As for the genus unless otherwise stated. Antenna 1 long, reaching from midpoint to end of article 5 of antenna 2 peduncle. Eye medium (1/5-1/3 of head length). Gnathopod 1 not sexually dimorphic, palm transverse, dactylus shorter than palm. Gnathopod 2 sexually dimorphic (male subchelate, female mitten-shaped). Pleopod 1 outer ramus subequal in length to peduncle. Pleopod 3 outer ramus longer than peduncle.
Material examined.
Holotype, male, 8.04 mm, THNHM-Iv- 18760; allotype, female, 7.80 mm, THNHM-IV- 18961; Paratypes, 2 males, 1 non-gravid female, and 2 gravid females, THNHM- Iv 18761. All collected from the type locality on 4 May 2019, KW and PD leg.
Ecology.
Driftwood hoppers, living inside rotten logs and mangrove roots in the softest part under the bark. The mangrove forest is located near a small creek 50 meters from the beach. The sediment in the forest is muddy sand mixed with leaf litter.
Type locality.
Mangrove forest near Ban Ao Prao Beach (11°35'40.2"N, 102°33'52.6"E), Ko Kut District, Trat Province, Thailand.
Etymology.
The specific epithet refers to the habitat of this amphipod, which is also found inside mangrove roots.
Description of male holotype.
(THNHM-Iv- 18760, Figs 2 View Figure 2 - 5 View Figure 5 ).
Head. Eye medium (1/5-1/3 head length). Antenna 1 (Fig. 2A1 View Figure 2 ) long, reaching from midpoint to end of article 5 of antenna 2 peduncle. Antenna 2 (Fig. 2A2 View Figure 2 ) peduncular articles slender, article 5 longer than article 4. Upper lip (Fig. 3UL) without robust setae. Mandible (Fig. 3LMD) left lacinia mobilis 4-dentate. Maxilla 1 (Fig. 3MX1) with small palp, 1-articulate. Maxilliped (Fig. 3MP) palp article 2 distomedial lobe absent; article 4 small, well defined.
Pereon. Gnathopod 1 (Fig. 2G1 View Figure 2 ) sexually dimorphic; subchelate; coxa 1 smaller than coxa 2; posterior margins of merus, carpus, and propodus each with lobe covered in palmate setae, palmate lobes present; propodus shorter than carpus, subrectangular; palm transverse. Gnathopod 2 (Fig. 2G2 View Figure 2 ) sexually dimorphic; subchelate; coxal gill simple (or slightly lobate); basis slender; carpus triangular, reduced (enclosed by the merus and propodus), posterior lobe absent, not projecting between merus and propodus; 1.8 × as long as wide; palm acute, weakly toothed, with a subquadrate protuberance near dactylar ringe, lined with robust setae, posterodistal corner with socket; dactylus subequal in length to palm. Pereopod 3-4 (Fig. 4P3-P4 View Figure 4 ) coxae wider than deep. Pereopods 3-7 (Fig. 4P3-P7 View Figure 4 ) simplidactylate. Pereopod 4 (Fig. 4P4 View Figure 4 ) subequal or slightly shorter than pereopod 3; carpus similar in length to pereopod 3 carpus; dactylus similar to pereopod 3 dactylus. Pereopod 5 propodus distinctly longer than carpus. Pereopod 6 (Fig. 4P6 View Figure 4 ) slightly sexually dimorphic; shorter than pereopod 7; coxa posterior lobe inner view posteroventral corner rounded, posterior margin oblique with respect to ventral margin, posterior lobe without a ridge, posterior lobe without marginal setae; coxal gill lobate. Pereopod 7 (Fig. 4P7 View Figure 4 ) sexually dimorphic (merus and carpus broadly incrassate); basis lateral sulcus absent, posterodistal lobe absent; distal articles (merus and carpus) expanded; merus posterior margin expanded distally, subtriangular.
Pleon. Pleopods all well developed. Pleopod 1 (Fig. 5PL1) peduncle without marginal setae; biramous, outer ramus subequal in length to peduncle; inner ramus with 17 articles, outer ramus with 13 articles. Pleopod 2 (Fig. 5PL2) peduncle without marginal setae; biramous, outer ramus subequal in length to peduncle; inner ramus with 15 articles, outer ramus with 14 articles. Pleopod 3 (Fig. 5PL3) peduncle without marginal setae; biramous, outer ramus subequal in length to peduncle; inner ramus with 15 articles, outer ramus with 13 articles. Uropod 1 (Fig. 5U1 View Figure 5 ) peduncle with 4 robust setae, distolateral robust seta present, large (1/4 length of outer ramus), with simple tip; inner ramus subequal in length to outer ramus, inner ramus with marginal robust setae; outer ramus with 3 marginal robust setae. Uropod 2 (Fig. 5U2 View Figure 5 ) inner ramus subequal in length to outer ramus, with marginal robust setae, with 3 lateral robust setae; outer ramus without marginal robust setae. Uropod 3 (Fig. 5U2 View Figure 5 ) peduncle with 2 robust setae; ramus shorter than peduncle, ramus triangular, with 2 apical setae. Telson (Fig. 5T View Figure 5 ) longer than broad, apically incised, dorsal midline vestigial or absent, with apical robust setae only and 2 robust setae per lobe.
Description of female allotype.
(THNHM-Iv- 18761, Figs 6 View Figure 6 - 7 View Figure 7 )
Pereon. Gnathopod 1 (Fig. 6G1 View Figure 6 ) propodus narrower than that of male; dactylus subequal to palm. Gnathopod 2 (Fig. 6G2 View Figure 6 ) mitten-shaped; basis slightly expanded; posterior margins of merus, carpus, and propodus each with lobe covered in palmate setae; carpus well developed (not enclosed by merus and propodus), posterior lobe present, projecting between merus and propodus; propodus length twice as long as wide; palm obtuse, smooth, without a protuberance or shelf near dactylar hinge, posterodistal corner naked; dactylus shorter than palm; gill lobate. Pereopod 5 (Fig. 7P5 View Figure 7 ) propodus shorter than carpus. Distal articles (merus and carpus) slender. Preopods 6-7 (Fig. 7P6-7 View Figure 7 ) sexually dimorphic (merus and carpus not broadly incrassate). Oostegites long (length greater than 2 × width), longer than wide, weakly setose, setae with simple, smooth tips.
Habitat.
Mangrove wood, inside roots and rotting logs.
Distribution.
Thailand, Ko Kut District, Inner Gulf of Thailand.
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