Metopomystrum Guenther , 1939

Silva, Daniela Santos Martins, Skejo, Josip, Pereira, Marcelo Ribeiro, Domenico, Fernando Campos De & Sperber, Carlos Frankl, 2017, Comments on the recent changes in taxonomy of pygmy unicorns, with description of a new species of Metopomystrum from Brazil (Insecta, Tetrigidae, Cleostratini, Miriatrini), ZooKeys 702, pp. 1-18 : 1

Genus Metopomystrum Guenther, 1939

= Apteromystrum Storozhenko, 2016, syn. n.

Type species.

Metopomystrum pehlkei Günther, 1939 by original designation.

Composition and distribution.

Five species, all in northern part of South America (Brazil, Colombia), namely (1) M. amazoniensis (Colombia: Amazonas), (2) M. apterum (Brazil: Bahia), (3) M. lilianae (Colombia: Santander), (4) M. muriciense Silva & Skejo, sp. n. (Brazil: Alagoas), and (5) M. pehlkei (Colombia: Tolima).

Revised generic description.

Head. Frontal costa bifurcation situated above the paired lateral ocelli, between the compound eyes, so the frontal costa is long and evident before bifurcation, scutellum narrower than scapus, antennal grooves situated at the level of the lower margins of the compound eyes, paired lateral ocelli situated between the compound eyes, head and eyes exserted above pronotum, eyes protruding, so the vertex is not visible in lateral view, antennae 15-segmented, filiform, with cylindrical segments and smooth margins, fastigium narrower than the compound eyes, lateral carinae of the vertex continuous, not elevated, median carina of the vertex very weak, almost absent, anterior margin of the vertex rounded or acute, fastigium of the vertex projecting forwards and forming a horn longer than combined length of a compound eye and frontal costa above its bifurcation, dorsum of the horn with deep depression formed of joined fossulae, frontal ridge in lateral view with weak excision between the compound eyes.

Pronotum. slender in appearance, anterior margin truncated, prozonal carinae present, parallel or slightly diverging, extralateral carinae indistinct, median carina continuous from the anterior margin to the posterior apex, pronotal projections lacking, humeral angle wide, obliquely rounded, interhumeral carinae indistinct, interscapular area in winged species narrow with parallel margins, in wingless species as wide as mid femur, lateral area wider in wingless species, humero-apical, humeral and lateral carinae continuous, not armed or tuberculated, paranota triangular, lateral lobes of the pronotum directed slightly sidewards, with rounded apex lacking ventrolateral spine, dorsum of pronotum between the carinae smooth, pronotal apex truncated or acute.

Legs. Fore and mid femora not significantly compressed, fore femora with straight to slightly undulated dorsal and ventral margins, not armed with teeth or spines, mid femora not compressed, carinated above, with straight to slightly undulated dorsal and more undulated ventral margins, hind femora with smooth dorsal and ventral margins, dorsal margin with genicular and antigenicular teeth in hind knee, transverse ridges in the external surface well visible, not armed with lappets or spines, hind tibiae and tarsi not flattened or widened.

Revised generic diagnosis.

From other genera previously assigned to Cleostratini or Miriatrini , and from all the South American Metrodorinae genera ( Allotettix Hancock, 1899; Amorphopus Serville, 1838; Chiriquia Morse, 1900; Cota Bolívar, 1887; Cotys Bolívar, 1887; Crimisus Bolívar, 1887; Eomorphopus Hancock, 1900; Hancockiella Cadena-Castañeda & Cardona, 2015; Metrodora Bolívar, 1887; Miriatra Bolívar, 1906; Otumba Morse, 1900; Platythorus Morse, 1900; Plesiotettix Hancock, 1907; Scabrotettix Hancock, 1907 and Trigonofemora Hancock, 1906). The genus Metopomystrum can be separated by the following set of characters: head exserted above the pronotum, frontal costa long above the bifurcation, antennal grooves situated at the level of the lower margins of the compound eyes, antennae 15-segmented, filiform, paired lateral ocelli situated between the compound eyes, median carina of the vertex weak, indistinct, not projecting forwards and not compressed, fastigium of the vertex with deep depression, lateral carinae of the vertex continuous, pronotum flat, without projections and protuberances, lateral pronotal lobes directed sidewards, having rounded apices, femora without teeth or lappets, fore and mid femora not compressed and flattened.