Insularorchestia Lowry & Myers 2022, gen. nov.
Creators: name: Lowry, J. K.
name: Myers, A. A.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Talitridae
Insularorchestia

description: Insularorchestia gen. nov.
Type species. Orchestia ashmoleorum Stock, 1996, current designation.
Included species. Insularorchestia includes 3 species: I. ashmoleorum (Stock, 1996) com. nov.; I. monodi (Mateus, Mateus & Afonso, 1986) com. nov. and I. susorum sp. nov. of Stock & Biernbaum, 1994 com. nov..
Ecological type. Beach-hoppers, field-hoppers.
Habitat. Sand beaches and under stones at 762 m altitude (Stock & Biernbaum 1994).
Etymology. From islands.
Diagnostic description (male). Based on Mateus, Mateus & Afonso (1986), Stock (1996), Serejo (2004), Morino & Ortal (1995) and Stock & Biernbaum (1994).
Head. Antenna 2 peduncular articles incrassate. Mandible left lacinia mobilis 5- or 6-cuspidate. Labium without inner lobes, with possible vestigial inner lobes. Maxilliped palp article 2 with distomedial lobe; article 4 reduced, button-shaped or fused with article 3.
Pereon. Gnathopod 1 sexually dimorphic; subchelate; coxa much smaller that coxa 2; posterior margin of carpus and propodus each with lobe covered in palmate setae; propodus anterior margin with 3 or 4 groups of robust setae, subrectangular or ‘subtriangular’ with well-developed posterodistal lobe, palm transverse; dactylus simplidactylate. Gnathopod 2 subchelate; propodus palm acute, evenly rounded or irregular with small to large shallow midpalmar sinus or without distal palmar sinus; with or without proximal spine or thumb defining palm; dactylus not modified distally, blunt or short, recurved distally or attenuated distally. Pereopods 3–7 dactyli bicuspidactylate. Pereopod 4 significantly shorter than pereopod 3 or subequal or slightly shorter than pereopod 3; carpus similar in length to that of pereopod 3 or significantly shorter than that of pereopod 3; dactylus amplidactylate, thickened proximally with notch midway along posterior margin or short, thickened. Pereopod 6 subequal in length to pereopod 7, not incrassate; basis moderately expanded; male merus and carpus not expanded or male merus expanded, carpus not expanded. Pereopod 7 not incrassate; basis broadly expanded; posterior margin with distinct minute serrations, each with a small seta, posterodistal lobe present or posterodistal lobe absent, shallow, broadly rounded; merus expanded distally, subtriangular, anterior margin slightly convex; carpus unexpanded or expanded, subrectangular, subequal to or shorter than propodus; propodus broad or propodus slender; length 4.7–7.3 × width; propodus without large distal tuft of setae. Oostegites (female) setae with simple smooth tips.
Pleon. Pleopods 1–3 all well-developed. Uropod 1 peduncle distolateral robust seta 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 subequal in length to peduncle, or shorter than peduncle. Telson apically incised, with 3–6 robust setae per lobe.
Remarks. Insularorchestia is most similar to Platorchestia. It differs in having a simplidactylate gnathopod 1 (cuspidactylate in Platorchestia).
Distribution. South Atlantic Ocean. Saint Helena (Stock 1996); Ascension Island (Stock & Biernbaum 1994). North Atlantic Ocean. Azores (Mateus, Mateus & Afonso 1986).
description: Published as part of Lowry, J. K. & Myers, A. A., 2022, Platorchestiinae subfam. nov. (Amphipoda, Senticaudata, Talitridae) with the description of three new genera and four new species, pp. 1-53 in Zootaxa 5100 (1) on pages 17-19, DOI: 10.11646/zootaxa.5100.1.1, http://zenodo.org/record/6127681