Dicranostomus Dohrn, 1888

Heller, Klaus-Gerhard & Helb, Matthias, 2021, Revision of the tusked bush-crickets (Tettigonioidea: Pseudophyllinae: Dicranostomus) with description of the hitherto unknown sexes, Journal of Orthoptera Research 30 (1), pp. 87-94 : 87

Genus Dicranostomus Dohrn, 1888

Dicranostomus monoceros Type species: Dicranostomus monoceros Dohrn, by original monotypy

Redescription. -

[based on Dohrn 1888 (in Latin), Beier 1960 (in German)].

Medium sized (body length 2.5-4.0 cm), yellowish-brown animals (habitus; Fig. 1 ). Head as broad as pronotum or broader. Frons shiny, smooth. Fastigium frontis elongated, curved or straight. Fastigium verticis compressed, narrow, with longitudinal furrow. Antennae very long, scapus unarmed. Male mandible at base with a very long, horizontally directed tusk (Fig. 2 ). Pronotum smooth or slightly granulated, with delicate anterior and medially deeply incised posterior sulcus; metazona flat, only slightly longer than mesozona, laterally no edges, humeral sinus very weak; side lobes longer than high, ventrally nearly straight and finely edged, caudally weakly ascending, anterior edges even more broadly rounded than the also broadly rounded posterior edges. Openings of the tympanic organ in the fore tibia directing dorsally, slit-like. Auditory prothoracal spiracle quite small, just below the respiratory spiracle. Tegmina just surpassing abdomen, gradually becoming narrow, costal area with wide-meshed veins, Sc (subcosta) and R veins separated. The male mirror on both the left and right wing is translucent (Fig. 3 ). Teeth in stridulatory file regularly spaced (Fig. 4 ). Rs (radius sector) arising at the beginning of the apical quarter, media (M) and Sc stalked. Alae roundish, shorter than tegmina. Prosternum with two close spines between prothoracic legs. Mesosternal lobes pointed. Metafurcal pit deep. Middle coxae two-pronged. All femora ventrally armed. Inner genicular lobes of mid and hind femora with spine. Fore tibiae dorsally at the inner edge with a series of small humps. Mid tibiae dorsally with one to three spines internally. Supraanal plate triangular or rounded. Male cerci thick, nearly straight, with subapical spine and apical process (Fig. 5 ). Male subgenital plate distally narrowed, styli rod-like. Female subgenital plate transverse, slightly incised. Ovipositor short, relatively broad and slightly up-curved, at the upper edge very delicately crenulated (Fig. 6 ).

Distribution. -

South America, Peru (Fig. 7 ).

Figures

Fig. 1. Male habitus of A. Dicranostomus monoceros and B. D. nitidus (same scale for both figures).

Fig. 2. Morphological details of Dicranostomus monoceros (A-D) and D. nitidus (E-H; same scale for corresponding figures). A, E. Male head lateral; B, F. Male head frontal; C, G. Female head frontal; D, H. Female head semilateral.

Fig. 3. Mirror cells of Dicranostomus monoceros (A, B) and D. nitidus (C, D). A, C. Left tegmen; B, D. Right tegmen. Scale bar: 5 mm.

Fig. 4. Stridulatory files in Dicranostomus. A. D. monoceros (C _ Helb 8775); B. D. nitidus (CH 4225); C. Inter-tooth distances (specimens as in A, B). Scale bars: 1 mm (A, B).

Fig. 5. Male cerci of A. Dicranostomus monoceros and B. D. nitidus. Scale 1 mm.

Fig. 6. Ovipositor of A. Dicranostomus monoceros and B. D. nitidus (same scale for both figures).

Fig. 7. Distribution map of Dicranostomus (all known localities; map based on SimpleMappr (Shorthouse 2010 )).