Arostratum oblitum, Massa, Bruno, 2015

Massa, Bruno, 2015, New genera, species and records of Phaneropterinae (Orthoptera, Phaneropteridae) from sub-Saharan Africa, ZooKeys 472, pp. 77-102 : 87-89

Taxon classification Animalia Orthoptera Phaneropteridae

Arostratum oblitum sp. n. Figs 43, 44, 54-58

Material examined and depository.

NW Tanganyika (now Tanzania) 1910 (♂ holotype), Grauer (MfN).

General habitus and colour.

First antennal segments are black, other reddish, pronotum and tegmina green, abdomen brownish, femora green and yellowish, tibiae reddish. The apex of tenth tergite and of sub-genital plate are black.

Description.

Male. Head and antennae: fastigium of vertex compressed, much narrower than the first antennal segment, eyes round, prominent (Figs 57, 58). Antennae longer than the body. Legs: open tympana are present on both sides of fore tibiae. Coxae unarmed. 4 spines plus 1 apical spur are present on ventral external margin of fore tibiae, 1 spine is present on outer upper margin and no spurs are present on apical upper margins; mid tibiae with 3 spines on outer ventral margin plus 2 small apical spines; 2 apical spines are also present on inner ventral and on inner dorsal margins; hind tibiae have some spines on ventral margins plus 4 apical spines; many spines are present on upper margins of hind tibiae plus 2 apical ones; spines are absent on femora. Thorax: pronotum without lateral carinae, anteriorly narrower than on the posterior part, similar to that of Atlasacris , with a small inflated area on lower and posterior areas (Figs 43, 58). Tegmina are very short, not exceeding the 2nd abdominal segment (Figs 57-58). Wings are reduced to very small scales. As in Atlasacris , the stridulatory file matches the model described by Hemp et al. (2009) for Monticolaria ; it consists of about 50-60 teeth. The proximal part contains more teeth (about 40) than the distal part, which bears around 17-18 large, asymmetrical and widely spaced teeth, in the same space of former 40 teeth. The last tooth on the posterior border of left tegmen is similar to a hook, longer and bigger than previous ones (Fig. 44); it probably produces a sound similar to a click. The right tegmen has a wide triangular speculum that covers ca. ¾ of the tegmen length. Abdomen: tenth tergite almost straight with undulate and down-curved posterior margin (Figs 54, 55, 56), cerci are stout, in-curved, ending with a pointed black tip, placed at right angle (Fig. 56). The sub-genital plate is long with an apical v-shaped concavity and thickened lateral margins. Styli are absent (Fig. 54).

Female. Unknown.

Diagnosis.

Small species with very short wings and very long legs, pronotum anteriorly narrower than on the posterior part, with a small inflated area on lower and posterior areas.

Measurements.

Body length: 14.2; pronotum length: 3.4; fore femur: 11.2; mid femur: 10.4; hind femur: 20.0; hind tibiae: 24.0; tegmina: 4.8.

Etymology.

From Latin: oblitum = forgotten. The specimen here treated of Arostratum oblitum sp. n. was collected in 1910 and was forgotten for 73 years, when in 1983 D. Ragge studied it and established that it was belonging to one unidentified genus; finally, 104 years after its collection it is described.