Miyamotoia Morino, 2020

Lowry, J. K. & Myers, A. A., 2022, Platorchestiinae subfam. nov. (Amphipoda, Senticaudata, Talitridae) with the description of three new genera and four new species, Zootaxa 5100 (1), pp. 1-53 : 29-30

Miyamotoia Morino, 2020

Miyamotoia Morino, 2020: 2 .

Type species. Miyamotoia spinolabrum Morino, 2020 , original designation.

Included species. Miyamotoia contains 2 species: M. daitoensis Morino, 2020 ; M. spinolabrum Morino, 2020 .

Category. Mascupod.

Ecological type. Forest-hopper.

Habitat. Humid forests.

Diagnostic description (male). Based on Morino (2020).

Head. Antenna 2 peduncular articles slender. Mandible left lacinia mobilis 5-cuspidate. Labium without inner lobes. Maxilliped palp article 2 with distomedial lobe; article 4 reduced, button-shaped.

Pereon. Gnathopod 1 sexually dimorphic; subchelate; coxa slightly smaller than coxa 2; posterior margin of carpus and propodus each with lobe covered in palmate setae; propodus anterior margin with 3 or with 4 groups of robust setae, ‘subtriangular’ with well-developed posterodistal lobe, palm transverse; dactylus simplidactylate. Gnathopod 2 subchelate; propodus palm acute; propodus palm evenly rounded, without palmar sinuses; without proximal spine or thumb defining palm, without large projection near dactylar hinge; dactylus short, recurved distally or attenuated distally (short). Pereopods 3–7 dactyli bicuspidactylate. Pereopod 4 subequal or slightly shorter than pereopod 3; carpus significantly shorter than that of pereopod 3; dactylus amplidactylate, thickened proximally with notch midway along posterior margin or short with mini-wavy posterior margin. Pereopod 6 subequal in length to pereopod 7, not incrassate; basis moderately expanded; male merus and carpus not expanded. Pereopod 7 not incrassate; basis broadly expanded; posterior margin with distinct minute serrations, each with a small seta, posterodistal lobe present, shallow, narrowly rounded; merus unexpanded; carpus unexpanded; propodus broad, 6.1 × width, without large distal tuft of setae. Oostegites (female) setae with simple smooth tips.

Pleon. Pleopods all reduced. Uropod 1 peduncle distolateral robust seta present or absent; exopod without marginal robust setae; endopod with marginal robust setae in 2 rows. Uropod 2 exopod with marginal robust setae in 1 row; endopod with marginal robust setae in 2 rows. Uropod 3 ramus shorter than peduncle. Telson apically incised, with 3 to at least 10 robust setae per lobe.

Remarks. Miyamotoia is similar to Laniporchestia from Hawaii. See remarks under Laniporchestia . Miyamotoia is also similar to Tethorchestia . The main differences are gnathopod 1 dactylus is simplidactylate (cuspidactylate in Tethorchestia ), pereopod 7 propodus without a large, distal tuft of setae (present in Tethorchestia ), uropod 1 peduncle without a distolateral robust seta (present in Tethorchestia ) and the endopod of uropod 1 with marginal setae in two rows (one row in Tethorchestia ).

Distribution. Japan: Ogasawara Islands and Daitojima Islands, Southern Japan ( Morino 2020).