Amorphopini Günther, 1939

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, Zootaxa 5597 (1), pp. 1-265 : 177-183

Tribe Amorphopini Günther, 1939

Type genus: Amorphopus Serville, 1838 .

Enmended description. Body robust, depressed dorso-ventrally ( Figs. 121A , 122A ), small to medium size (15–20 mm.). Head little exserted. In frontal view, face ovoid, taller than wide; upper margin of the vertex at the same level as the lateral carinae; fastigium rounded; medial carina not elevated; lateral carinae moderately elevated, without exceeding eyes level, slightly more elevated than the median one; vertex varying from narrower to as wide as an eye. Scutellum narrow or moderately widened, without exceeding the width of the scape; frontal costa mid-sized, and bifurcation usually at the middle of the eyes or at the level of the lower margin of the eye sockets. In lateral view, medial carinae not protruding beyond the eyes and slightly tapering; anterior margin of the vertex truncated; fastigium of the vertex not forming an elongated horn, and dorsum without fossulae. Antennal groves located at level of the lower margin of the eyes, rarely lower or in the middle of the face; antennae usually mid-sized, as long as the middle femur or exceeding it, with 15 segments. Eyes rounded, straight at lower margin, small or medium-sized, protruding slightly above the vertex, occupying a quarter or a fifth of the cephalic capsule. Lateral ocelli placed between the middle part, or near the lower margin of the eyes and the base from where each branch of the fascial carinae diverges; medial ocellus located close to the lower margin of the scutellum; palpi with last three segments flattened, first two segments short and nearly cylindrical ( Figs. 121B , 122B , 123B , 124B ). Thorax. Pronotum robust and granulated, surpassing the tip of the abdomen. Pronotal disc with a straight or rounded anterior margin and a pointed posterior margin, dorsally flat; median carina slightly elevated, midline from mesozone to the apex ( Figs. 121A , 122A , 123A , 124A , 125A ). Lateral lobes of pronotum rectangular in lateral view ( Figs. 121C , 122C , 123C , 124C , 125C ), lower edge well projected to the sides, with rounded ( Figs. 121D , 122D ) or acute apex ( Figs. 123D , 124D , 125D ); humeral angle wide, obliquely concave; infrascapular area thin and projecting between the second or third abdominal segment; lateral area narrow slightly wider than the infrascapular area, arising next to the dorsal undulation of the infrascapular area ( Figs. 121A , 122A , 123A , 124A , 125A ). Wings. All known species winged; tegmina ovoid, almost lanceolate ( Figs. 121C , 122C , 124C ); hind wings reaching the apex of the pronotum or slightly exceed it. Legs. Fore femur carinated ( Figs. 123E , 124E , 125E ) and middle femur strongly expanded; dorsal and ventral margin of middle femur lobed or foliaceous ( Figs. 121F , 122F , 123F , 124F , 125F ); hind femur with antegenicular and genicular teeth developed, transversal ridge (or “chevrons”) between the dorso and ventro external carinae, and transversal ridge between the dorsal margin of the hind femur and dorso-external carina. Abdomen. Male: last segments, between eighth and ninth segments, moderately constricted. Subgenital plate cupuliform, as long as or longer than the last abdominal sternite; apex of the subgenital plate rounded or angled, and with pointed apex. Cerci conical ( Figs. 122H , 124H , 125H ). Female: Epiproct triangular or ovoid, with medial groove. Subgenital plate mainly triangular, with a small spine at the apex. Ovipositor valves moderately robust, with serrulations of medium length ( Figs. 121H , 123H ); inferior valves not conspicuously covered by the lateral edges of the subgenital plate ( Figs. 121G , 123G ).

Genera included. Amorphopus Serville, 1838 and Eomorphopus Hancock, 1907 .

Distribution. South America, mainly in the Amazon and Guyanese regions (Map 8).

MAP 8. Distribution of Amorphopini species.

Remarks. The taxa of this group camouflage themselves between lichens and bryophytes, with modified body structures that make them almost unnoticed. This tribe was established by Cadena-Castañeda & Cardona-Granda (2015), based on the ancient name “Amorphopi,” which was used by Günther (1939) to rename the section Metrodorae when considering Metrodora in the Cladonotae section. Recently, Cadena-Castañeda et al. (2020) studied the genera and species, providing taxonomic and distributional data and comprehensive descriptions of genera and species (for this reason, we do not redescribe those taxa here, we consider that the data provided there is sufficient), and a key to these fascinating insects is given below.

Key to genera and species of Amorphipini (after Cadena-Castañeda et al., 2020)

1. Body strongly depressed ( Figs. 121A, D , 122A, D ). Scutellum wide ( Fig. 120B , 122B ); fore and middle femora flattened, foliaceous, and clypeate ( Figs. 121E, F , 122E, F ); tegmina ovoid ( Figs. 121C , 122C )....................... A. notabilis

- Body moderately depressed ( Figs. 123A , 124A , 125A ). Scutellum narrow ( Figs. 123B , 124B , 125B ); only middle femora flattened ( Figs. 123F , 124F , 125F ), fore femur carinated ( Figs. 123E , 124E , 125E ); tegmina sub-lanceolate ( Fig. 124C ). ( Eomorphopus )....................................................................................... 2

2. Mid-sized (females: 19–19.5 mm ( Figs. 123A, D ), male: 18 mm ( Fig. 124A, D )). Apex of the lateral lobes of the pronotum (sideway projection) triangular-shaped and moderately sharp ( Figs. 123D , 124D ). Body granulose, prozona with rounded sculpturing ( Figs. 123C , 124C )................................................................ E. antennatus

- Small-sized (females: 16.5–17.5 mm, males: 15–16 mm ( Figs. 125A, D )). Apex of the lateral lobes of the pronotum (sideway projection) rounded ( Fig. 125D ). Body mostly smooth and slightly granulose, prozona without sculpturing ( Fig. 125C ).............................................................................................. E. granulatus

Figures

FIGURE 120. Platythorus camurus Morse, 1900. Female holotype. A. Habitus in lateral view. B. Habitus in dorsal view. C. Frons. D. Labels. Photos: J. Tumbrinck.

FIGURE 121. Amorphopus notabilis Serville, 1838. Female. A. Habitus in lateral view. B. Frons. C. Head and thorax in lateral view. D. Habitus in dorsal view. E. Fore-femur. F. Mid-femur. G. Terminalia in ventral view and H. In lateral view. (Adapted from Cadena-Castañeda et al. 2020).

FIGURE 122. Amorphopus notabilis Serville, 1838. Male. A. Habitus in lateral view. B. Frons. C. Head and thorax in lateral view. D. Habitus in dorsal view. E. Fore-femur. F. Mid-femur. G. Terminalia in ventral view and H. In lateral view. (Adapted from Cadena-Castañeda et al. 2020).

FIGURE 123. Eomorphopus antennatus (Bolívar, 1887). Female. A. Habitus in lateral view. B. Frons. C. Head and thorax in lateral view. D. Habitus in dorsal view. E. Fore-femur. F. Mid-femur. G. Terminalia in ventral view and H. In lateral view. (Adapted from Cadena-Castañeda et al. 2020).

FIGURE 124. Eomorphopus antennatus (Bolívar, 1887). Male. A. Habitus in lateral view. B. Frons. C. Head and thorax in lateral view. D. Habitus in dorsal view. E. Fore-femur. F. Mid-femur. G. Terminalia in ventral view and H. In lateral view. (Adapted from Cadena-Castañeda et al. 2020).

FIGURE 125. Eomorphopus granulatus Hancock, 1907. Male. A. Habitus in lateral view. B. Frons. C. Head and thorax in lateral view. D. Habitus in dorsal view. E. Fore-femur. F. Mid-femur. G. Terminalia in ventral view and H. In lateral view. (Adapted from Cadena-Castañeda et al. 2020).