Metrodorina, Cadena-Castañeda & Quintana-Arias & Infante & Silva & Tavares, 2025

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 : 12-14

publication ID	https://doi.org/10.11646/zootaxa.5597.1.1
publication LSID	lsid:zoobank.org:pub:E8B87293-0CCD-469D-9F2F-17F1AB4919BF
persistent identifier	https://treatment.plazi.org/id/542B87FD-FFA9-0417-9FDE-C563FEF4F839
treatment provided by	Plazi
scientific name	Metrodorina
status

Treatment

Subtribe Metrodorina Bolívar, 1887, stat. nov.

Type genus: Metrodora Bolívar , 1887.

Emended description. Body small and robust (6–9 mm.). Carinae of the vertex poorly ( Figs. 1A View FIGURE 1 , 10B View FIGURE 10 ) or well-produced ( Figs. 26B View FIGURE 26 , 29B View FIGURE 29 , 49B View FIGURE 49 ); lateral carinae of the vertex without pronounced horns or with horns moderately developed. Antennae with 14–15 segments ( Figs. 10C View FIGURE 10 , 22C View FIGURE 22 , 29C View FIGURE 29 ). Scutellum generally two or three times wider than scape. Frontal costa branches usually curved or diverging, rarely straight ( Figs. 10A View FIGURE 10 , 26C View FIGURE 26 , 29A View FIGURE 29 ). Pronotal disc progressively narrowing towards the apex. Hind margin of pronotum pointed ( Figs. 1C View FIGURE 1 , 36B View FIGURE 36 ). Lower margin of lateral lobes of the pronotum conspicuously projected to the sides in the form of a spine, generally triangular ( Figs. 1E View FIGURE 1 , 29C View FIGURE 29 , 57C View FIGURE 57 ). Median carina of the pronotum mostly arcuate, forming a crest with different levels of development ( Figs. 10B View FIGURE 10 , 12A View FIGURE 12 , 22A View FIGURE 22 ), although in some genera with a flat pronotal disc ( Figs. 1A View FIGURE 1 , 30A View FIGURE 30 ). Tegminae and hind wings absent. Genicular tooth of hind femora well-developed ( Figs. 21A View FIGURE 21 , 33A View FIGURE 33 ).

Genera included. Metrodora Bolívar, 1887, Cota Bolívar, 1887, Tylotettix Morse, 1900 , stat. resurr., Platytettix Hancock, 1906 , stat. resurr., Hancockiella Cadena-Castañeda & Cardona, 2015 , Hebardidora Cadena-Castañeda & Tavares , gen. nov., Bolivaridora Cadena-Castañeda & Tavares , gen. nov., and Morseidora Cadena-Castañeda & Tavares , gen. nov.

Distribution. Mainly diversified in the Amazon, but with taxa in the Andes of Peru , Ecuador, and Colombia, extending to Central America through Panama, Costa Rica, and Nicaragua (Map 1–4).

Remarks. In order to understand the taxonomic treatment proposed for Metrodorini , it is necessary to delimit the suprageneric taxa (such as the subtribe Metrodorina stat. nov.). Compared to Mucrotettigina stat. nov., the differentiation of the genera is very diffuse, and is not in accordance with the organization of the Antillean taxa. For this reason, the same treatment is given to the Metrodorina stat. nov. and Mucrotettigina stat. nov. genera. Metrodorina stat. nov. remained with eight genera, of which three are new, and two are revalidated. The descriptions or redescriptions provided here are made ignoring characters mentioned in the tribe or subtribe descriptions. The following key to genera is provided here.

Key to genera of Metrodorina

1. Carinae of the vertex produced, conspicuously protruding in the middle of the eyes in lateral view ( Figs. 26B View FIGURE 26 , 29B View FIGURE 29 , 34B View FIGURE 34 , 47B View FIGURE 47 )............................................................................................... 2

- Carinae of vertex low, not protruding between the eyes, if so, slightly ( Figs. 1A View FIGURE 1 , 10B View FIGURE 10 )............................... 7

2. Body granulated with spine-like tubercles over the tegument ( Figs. 25B View FIGURE 25 , 26D View FIGURE 26 , 27C View FIGURE 27 ). Pronotum bicuspid, with rounded undulations, generally with one on the anterior section and another smaller one on the posterior section of the pronotal disc ( Figs. 25A View FIGURE 25 , 26A View FIGURE 26 , 27A View FIGURE 27 ). Legs with lappets and spiniform protuberances ( Figs. 27D View FIGURE 27 , 28B View FIGURE 28 , 29D View FIGURE 29 )..................... Cota View in CoL

- Body smooth or with small granulations ( Figs. 32 View FIGURE 32 , 33 View FIGURE 33 , 42 View FIGURE 42 ). Pronotum with or without crest; if present, located mainly in the anterior section of the pronotal disc ( Figs. 21A View FIGURE 21 , 31 View FIGURE 31 , 34B View FIGURE 34 , 43C View FIGURE 43 ). Legs without lappets or spines, with undulations only on the dorsal and ventral margins of the fore and mid femora ( Figs. 22D, 22E View FIGURE 22 , 51D, 51E View FIGURE 51 )................................. 3

3. Median carinae sub-elevated or not elevated; therefore, the pronotal disc is mostly flat ( Figs. 30A View FIGURE 30 , 42 View FIGURE 42 ). Scutellum narrow (Figs. 430C, 3D)........................................................................................... 4

- Median carinae elevated, and configured in different shape, such as a hump or a continuous crest ( Figs. 31A View FIGURE 31 , 35 View FIGURE 35 , 58A View FIGURE 58 ). Scutellum mostly wide ( Figs. 34A View FIGURE 34 , 31C View FIGURE 31 )........................................................................... 5

4. Lateral lobes of the pronotum with the lower margin pointed ( Figs. 47C View FIGURE 47 , 57C View FIGURE 57 ); apex of the pronotum unmodified ( Figs. 48A View FIGURE 48 , 55B View FIGURE 55 ).............................................................................. Bolivaridora gen. nov.

- Lateral lobes of the pronotum with the lower margin armed with a thin and curved-forward spine ( Fig. 30B View FIGURE 30 ); apex of the pronotum with a small spiny projection pointing upwards ( Figs. 30D View FIGURE 30 ).................................. Hancockiella View in CoL

5. Anterior margin of pronotum slightly projected over the head, hook-like ( Fig. 58A View FIGURE 58 ). Crest formed by the elevated and moderately flattened laterally median carina ( Fig. 58B View FIGURE 58 ), projecting to the apex of the pronotal disc, which exceeds the apex of the abdomen ( Fig. 58C View FIGURE 58 ).......................................................................... Morseidora gen. nov.

- Anterior margin of pronotum rounded ( Figs. 4A View FIGURE 4 , 37B View FIGURE 37 ). Crest wavy, formed by the elevated wavy median carina; apex of the pronotum not or slightly exceeding the apex of the abdomen ( Figs. 3B View FIGURE 3 , 38 View FIGURE 38 )....................................... 6

6. Median carina elevated of pronotum progressively curving from anterior margin to the apex ( Figs. 2A View FIGURE 2 , 3A View FIGURE 3 , 4A View FIGURE 4 ). Infrascapular area with medium width, reaching up to the fourth to sixth abdominal segment ( Figs. 3B View FIGURE 3 , 4B View FIGURE 4 )........ Tylotettix View in CoL stat. resurr.

- Median carina elevated, generally with a conspicuous hump on the anterior section of the pronotum and a minor undulation from the central section to the apex ( Figs. 31A View FIGURE 31 , 34B View FIGURE 34 ). Infrascapular area wide and more conspicuous than the previous genus, reaching up to the eighth or ninth abdominal segment ( Figs. 32A View FIGURE 32 , 33A View FIGURE 33 , 36A View FIGURE 36 ).................... Hebardidora gen. nov.

7. Scutellum wide ( Figs. 10A View FIGURE 10 , 22A View FIGURE 22 ). Median carina elevated, forming a hump that rises conspicuously and occupies the anterior half of the pronotal disc ( Figs. 10B View FIGURE 10 , 12A View FIGURE 12 ). Dorsal and ventral margins of the fore and middle legs conspicuously wavy, forming small extensions ( Figs. 16D, 16E View FIGURE 16 , 22D, 22E View FIGURE 22 )............................................. Platytettix View in CoL stat. resurr.

- Scutellum almost narrow ( Fig. 1D View FIGURE 1 ). Median carina sub-elevated and pronotal disc flat ( Fig. 1C View FIGURE 1 ). Dorsal and ventral margins of the forelegs and middle legs poorly undulated, and without prolongations along the margins ( Figs. 1A View FIGURE 1 )......... Metrodora View in CoL

Genus Metrodora View in CoL Bolívar, 1887

Metrodora View in CoL Bolívar, 1887: 242.

Metrodora View in CoL (partim): Günther, 1939: 292

Type species: Metrodora rana Bolívar, 1887, by subsequent designation ( Kirby, 1910).

Redescription. Body granulated and robust ( Figs. 1A, C View FIGURE 1 ). Head little exserted. In frontal view: vertex wider than an eye; medial and lateral carinae similar in length; frontal costa bifurcation located at the middle of the eyes; scutellum almost narrow, fascial carinae slightly divergent; upper margin of the antennal grooves almost at the same level of the lower margin of the eyes; lateral ocelli between the inferior part of the eyes, near the base from where each branch of the fascial carinae diverges; medial ocellus on the lower margin of the scutellum; antennae situated below the level of the eyes; palpi narrow, with apical segments moderately depressed ( Fig. 1D View FIGURE 1 ). In lateral view: carinae of the vertex low and short and not protruding between the eyes; fastigio-fascial angle rounded; fascial carinae compresso-elevated between the antennae, above and below abruptly sinuate; eyes subglobose, with a rounded dorsal surface, almost straight ventral margin and slightly elevated above the vertex ( Fig. 1A View FIGURE 1 ). Thorax. Pronotum robust, not surpassing the tip of the hind femora ( Fig. 1A View FIGURE 1 ). Pronotal disc flattened above, median carina subelevated and widened between the humeral angles, anteriorly straight and posterior apex pointed ( Fig. 1C View FIGURE 1 ). Humeral angles concave; angles of the lateral lobes outwardly acute and flattened in dorsal view ( Fig. 1E View FIGURE 1 ). Infra-scapular area wide and extending to the fifth or sixth abdominal segment; lateral area originating from the upper half of the infrascapular area and with same width from the base to the apex in lateral view ( Fig. 1A View FIGURE 1 ). Wings absent. Legs slightly elongated. Fore and mid-femora compressed and without conspicuous undulations. Hind femora with ante-genicular tooth moderately developed; genicular tooth triangular and with apex rounded. Hind tibia scarcely ampliated near the apex; the first and third segments of the hind tarsi equal in length. Abdomen. Last segments (from seventh to tenth) constricted and tapering dorsally, joining towards the anterior portion; cerci conical and reduced; penultimate sternite long, 2.5 times longer than the subgenital plate, slightly curved upwards; subgenital plate short, cupuliform and with rounded apex ( Fig. 1A View FIGURE 1 ).

Female. Unknown.

Species included. The type species only.

Distribution. The type locality of Metrodora rana is known only as “Alto Amazonas ” (=Upper Amazon), without a precise locality. However, “Alto Amazonas ” is a Peruvian province located in the west of the department of Loreto, with its capital in the city of Yurimaguas, which has existed since 1866, and this could be the location of this and other species described by various authors such as Brunner von Wattenwyl and Redtenbacher, among others (Maps 1, 2).

Remarks. To date, the genus Metrodora , included thirteen species, which are being reassigned to genera previously synonymized under Metrodora ( Tylotettix stat. resurr. and Platytettix stat. resurr.) and others that are being described here as new. In this way, the same approach is applied in terms of organization and morphological differentiation to the Antillean taxa to balance the generic limits.After the reassignment of taxa, Metrodora remained monotypic, although probably closely related to Platytettix stat. resurr., due to the shape of the medial and lateral carinae of the vertex.

The definition of Metrodora from its original description ( Bolívar 1887) was not efficiently defined since it included other species that are currently allocated in different genera, such as Otumba amazonica ( Bolívar, 1887), Bolivaridora lutosa ( Bolívar, 1887) comb. nov., Stalitettix spinifrons ( Stål, 1861) comb. nov. and Devrieseium concinnum ( Bolívar, 1887) comb. nov. So, Bolívar’s description would not fit the current taxonomic organization. Until now, Hancock (1907) was the one who provided the closest description to the generic definition proposed here, including only M. rana and R. lutosa comb. nov. Kirby (1910) selected M. rana as the type species of the genus. Günther (1939) added new species and synonymized Tylotettix stat. resurr. and Platytettix stat. resurr. under Metrodora , a classification that has remained until now. This contribution provides a redescription that delimits the genus and its only species to avoid future ambiguities, thus contributing to the stability of the subfamily Metrodorinae .