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| Thailandorchestia rhizophila Wongkamhaeng, Dumrongrojwattana, Sumitrakij & Saetung Keetapithchayakul, 2022 กุ้งเต้นเจาะไม้ | facebook.com/KoraonWongkamhaeng |
Abstract
During a scientific survey, a new genus of driftwood hopper was found in mangrove roots in Ko Kut District, Trat Province, Thailand. We placed this new genus, Thailandorchestia gen. nov., within the family Protorchestiidae. The new genus can be distinguished from the remaining genera by uropod 1 outer ramus with robust setae, uropod 2 outer ramus without robust setae, and pereopod 7 basis without a posterodistal lobe. The type species of Thailandorchestia gen. nov., Thailandorchestia rhizophila sp. nov., is described herein, and an updated key to the genera of the family Protorchestiidae is provided.
Keywords: Description, Ko Kut District, marsh hopper, Talitroidea, Thailandorchestia gen. nov.
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| Thailandorchestia rhizophila sp. nov. a holotype, male, 8.04 mm, THNHM-Iv- 18760 b allotype, female, 7.80 mm, THNHM-IV- 18961 c rotting mangrove log, habitat of Thailandorchestia rhizophila sp. nov. |
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| Thailandorchestia rhizophila sp. nov. holotype, male, 8.04 mm, THNHM-Iv- 18760. Scale bars: 1 mm. |
Systematics
Order Amphipoda Latreille, 1816
Suborder Senticaudata Lowry & Myers, 2013
Family Protorchestiidae Myers & Lowry, 2020
Genus Thailandorchestia gen. nov.
Diagnosis: Protorchestiidae with maxilliped palp article 2 distomedial lobe absent. Mandible left lacinia mobilis 4-dentate. Gnathopod 2 coxal gill simple. Pereopod 4 carpus significantly shorter than carpus of pereopod 3. Pereopods 6–7 sexually dimorphic (male merus and carpus incrassate). Pereopod 7 posterodistal lobe absent. Uropod 1 peduncle distolateral robust setae present, very large (1/3–1/2 length of outer ramus); inner ramus linear, not modified; outer ramus with marginal robust setae. Uropod 2 outer ramus without marginal robust setae. Uropod 3 peduncle with 2 robust setae; ramus shorter than peduncle, linear (narrowing). Telson apically incised, with 2 robust setae per lobe.
Etymology: The generic name, Thailandorchestia gen. nov., is derived from “Thailand” in combination with the Orchestia stem.
Type locality: Mangrove forest near Ban Ao Prao Beach (11°35'40.2"N, 102°33'52.6"E), Trat Province, Thailand.
Ecological type: Driftwood hoppers (virtually confined to rotting driftwood where they live in galleries, consuming rotting driftwood and reproducing with relatively small broods).
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.
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.
Etymology: The specific epithet refers to the habitat of this amphipod, which is also found inside mangrove roots.
Habitat: Mangrove wood, inside roots and rotting logs.
Distribution: Thailand, Ko Kut District, Inner Gulf of Thailand.
Koraon Wongkamhaeng, Pongrat Dumrongrojwattana, Ratchaneewarn Sumitrakij and Tosaphol Saetung Keetapithchayakul. 2022. Thailandorchestia rhizophila sp. nov., A New Genus and Species of Driftwood Hopper (Crustacea, Amphipoda, Protorchestiidae) from Thailand. ZooKeys. 1099: 139-153. DOI: 10.3897/zookeys.1099.82949
