Platytettix arcuatus Bruner 1920
Creators: name: Cadena-Castañeda, Oscar J.
name: Quintana-Arias, Ronald Fernando
name: Infante, Ivette Coque
name: Silva, Daniela Santos Martins
name: Tavares, Gustavo Costa
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Orthoptera
Tetrigidae
Platytettix
Platytettix arcuatus

description: Platytettix arcuatus Bruner, 1920, comb. ressur.
(Figs. 14–18, Map 1)
Platytettix arcuatus Bruner, 1920: 8. Holotype: female, FRENCH GUIANA, Pied Saut, Oyapok River (Fig. 14). Depository: ANSP.
Metrodora arcuatus: Otte, 1997: 50.
Material examined. 1 female and 1 male. BRAZIL, Pará, São Félix do Xingú, Parque Nacional da Serra do Pardo, 05°52’42”S, 52°47’45.6”W. [200 m.]; 25.04.2012; Pitfall; G. Ruiz, E. G. Cafofo-Silva & N. C. Bastos leg. (MPEG).
Description. Male (hitherto unknown). Small size (6.6 mm.). Body compact, granular, and moderately rugose (Fig. 15). Coloration generally dark brown, with ocher spots mainly on the legs and, to a lesser extent or diffusely, on the pronotum (Figs. 14, 15). Antenna with the first 9 or 10 segments brown, segments 10 (or 11) to 14 ochers (Figs. 16A, B); medial carina of the pronotum outlined in ocher, alternated with black spots visible laterally and dorsally; apex of the pronotum ocher (Figs. 16B, C); anterior and middle tibiae brown with ocher stripes (Figs. 16D, E), similarly, tarsomeres ocher with distal third of last segment brown; hind tibia ocher, with laterally diffused grayish spots, hind tarsomeres entirely ocher (Fig. 15A). Head taller than wide, with eyes occupying a quarter of the cephalic capsule, and medial carina moderately protruding in the middle of the eyes in lateral view; scutellum slightly wide; fascial carinae almost straight and parallel, protruding in lateral view and rounded; lateral ocelli located near the fork of the frontal costa (Fig. 16A). Antennae with 14 unmodifed segments (Figs. 16B, C). Thorax. Anterior margin of the pronotum almost straight, with only the medial section produced (Figs. 16B, C); prozonal carinae developed (Fig. 16B), pronotal apex pointed, and reaching the last abdominal segment (Fig. 15B). Pronotal hump progressively rising, and later truncating; dorsal margin of the hump produced by the median carina almost straight (Figs. 15A, 16B). Lower margins of lateral lobes triangular-shaped and pointed; posterior margin of lateral lobe rounded (Figs. 15B, 16C). Legs. Fore femur moderately dilated, basally constricted and then expanding, rectangular in shape, dorsally undulated, and ventrally with two triangular prolongations, the most conspicuous being the one located in the middle section of the femur (Fig. 16D). Mid femur rectangular, longer than wide and not as dilated as the fore femur, dorsal margin slightly curving throughout its length, ventral margin undulating, and with three short extensions (Fig. 16E). Hind femur with antegenicular and genicular teeth well-developed. Hind tibia armed with four or five small spines on each dorsal margin. Abdomen unmodified (Fig. 15A). Cerci conical, tapering towards the apical section and not diverging to the sides (Fig. 16F). Penultimate sternite longer and more conspicuous than the subgenital plate, and the posterior margin rounded (Fig. 16G); subgenital plate subtriangular in lateral view (Fig. 16G) and apex divided by a small V-shaped notch in axial view (Fig. 16H).
Female (emended description). Similar to the male in shape, coloration, and size (Figs. 14, 17, 18). The main differences include less conspicuous undulations on the fore and mid femur (Figs. 18A, B). Also distinguished by the ambisexual characters: tenth tergite divided by an ovoid plate that extends and connects with the epiproct; epiproct triangular, with rounded apex, and divided into three plates, two lateral rectangular plates on each side and a distal subtriangular plate with rounded apex (Fig. 18C); cerci conical tapering towards the distal section (Figs. 18C, D). Ovipositor valves with normal development and covered with bristles (Fig. 18D); subgenital plate quadrangular, nearly as long as wide, with posterior margin rounded and with a small triangular extension in the middle (Fig. 18E).
Measurements (in mm) male / female. CFP: 6.6 / 7.6. PL: 6.1 / 6.9. PLB: 4.5 / 4.9. FF: 1.5 / 2. FL: 1.4 / 1.5. MFL: 1.8 / 2.1. MTL: 1.4 / 1.8. HL: 3.8 / 4.8. HW: 1.7 / 2. HTL: 3.1 / 3.5.
Remarks. This species was originally described based on a female from Pied Saut, Oyapok River (French Guiana). This species is recorded here for the first time in Brazil, with specimens from the Pará State (Map 1). The specimens studied here fit the morphology and general coloration of the species, except for the apex of the lower margins of the lateral lobes of the pronotum, which are sharper than in the female holotype specimen.
Superficially, it can be confused with P. gibbinotus comb. ressur., which also has records in Pará (Brazil). Both species can be differentiated by the characters given in the key provided here, mainly separated by size and additionally by the median carina of the pronotum of P. arcuatus comb. ressur., which rises into a hump, outlined in yellow with black stripes or spots, and the fore and mid femora with more conspicuous extensions, in comparison to P. gibbinotus comb. nov.
description: Published as part of Cadena-Castañeda, Oscar J., Quintana-Arias, Ronald Fernando, Infante, Ivette Coque, Silva, Daniela Santos Martins & Tavares, Gustavo Costa, 2025, Studies on pygmy grasshoppers: On the current Metrodorinae sensu lato classification (Orthoptera: Tetrigidae) with emphasis on American and Malagasy taxa, pp. 1-265 in Zootaxa 5597 (1) on page 32, DOI: 10.11646/zootaxa.5597.1.1, http://zenodo.org/record/14966503