Thiorchestia caledoniana, Lowry & Fanini, 2023

Lowry, James K. & Fanini, Lucia, 2023, The Coastal Talitroid Amphipods of New Caledonia (Amphipoda: Talitroidea), Records of the Australian Museum (Rec. Aust. Mus.) 75 (4), pp. 471-484 : 478-481

Thiorchestia caledoniana sp. nov.

urn:lsid:zoobank.org:act:1514C5F2-9B6D-410E-B3B2-5907296E6184

Figs 5–7

Holotype: Male , 9.8 mm, AM P.100367 (SEM pin and 3 SEM stubs), Thio mission, Grand Terre, New Caledonia, 21°37.261'S 166°15.598'E, supralittoral, and extended black sand beach with pumice, hand collection with entomological aspirator, J. K. Lowry & L. Fanini, 27 December 2014 . Paratypes: 1 female, AM P.100368 (SEM pin and 1 SEM stub) , 1 male, 4 females (wet specimens), AM P.105706, Thio mission, Grand Terre, New Caledonia, 21°37.261'S 166°15.598'E, supralittoral, and extended black sand beach with pumice, hand collection with entomological aspirator, J. K. Lowry & L. Fanini, 27 December 2014 .

Additional material examined. 4 males, 1 female, AM P.97476, Mou , Grand Terre, New Caledonia, 21°06.105'S 165°26.924'E, estuary supralittoral, sandy beach, J. K. Lowry & L. Fanini, 2 January 2015 .

Type locality. Thio mission, Grand Terre, New Caledonia.

Diagnostic description. Male. Head. Antenna 1 slender or slightly incrassate. Mandible lacinia mobilis 5-cuspidate. Maxilliped palp article 2 with distomedial lobe; article 4 reduced, button shaped. Gnathopod 1 subchelate; posterior margin of carpus and propodus each with palmate lobe; dactylus cuspidactylate. Gnathopod 2 dactylus shortened distally, recurved. Pereopods 3–7 cuspidactylate (bicuspidactylate). Pereopod 4 dactylus thickened proximally with notch along posterior margin. Pereopod 7 not sexually dimorphic. Epimera 1–3 without slits. Pleopods well-developed. Uropod 1 exopod without marginal robust setae. Uropod 3 subequal in length to peduncle. Telson completely cleft with 6 marginal and apical robust setae.

Female (sexually dimorphic characters; based on paratype, AM P.100368). Gnathopod 1 posterior margin of merus, carpus, and propodus each without lobe covered in palmate setae. Propodus subrectangular, anterior margin with 4 groups of robust setae, palm acute. Dactylus simple, longer than palm. Gnathopod 2 mitten-shaped; basis slightly expanded; ischium without lobe on anterior margin. Posterior margin of 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; palm obtuse, nearly straight. Dactylus curved, posterior margin smooth, shorter than palm. Oostegites long (length greater than 2 × width), longer than wide, setose, setae with simple smooth tips.

Distribution. New Caledonia: Thio mission and Mou, Grand Terre.

Figures

Figure 5. Thiorchestia caledoniana sp. nov., holotype, male, 9.8 mm, AM P.100367; paratype, female, AM P.100368, New Caledonia. Scale: EP, H, MD, U1, UR 0.2 mm; remainder 0.1 mm.

Figure 6. Thiorchestia caledoniana sp. nov., holotype, male, 9.8 mm, AM P.100367; paratype, female, AM P.100368, New Caledonia. Scale: 0.2 mm.

Figure 7. Thiorchestia caledoniana sp. nov., holotype, male, 9.8 mm, AM P.100367, New Caledonia. Scale: P3, P4 0.1 mm; remainder 0.2 mm.