Austrodontura Fontana & Buzzetti, 2004

Naskrecki, Piotr & Bazelet, Corinna S., 2011, A revision of the South African katydid genus Austrodontura Fontana & Buzzetti (Orthoptera: Tettigoniidae: Phaneropterinae), Zootaxa 2873, pp. 51-59 : 52-54

Austrodontura Fontana & Buzzetti, 2004

Fontana and Buzzetti 2004: 451 >>original description; type species: Austrodontura raggei Fontana & Buzzetti , by original designation.

Description (male, except where specified)

General. Body of small to medium size for Phaneropterinae , robust, cylindrical; brachypterous ( Figs. 1 A, B, 2A, B); legs elongate.

Head. Head hypognathous, frons vertical, flat; antennae about twice as long as body; antennal scapus unarmed. Eyes globular, moderately protruding. Fastigium of frons small, separated from fastigium of vertex by distinct gap, fastigium of vertex at base nearly as wide as scapus, narrowing towards apex; triangular, blunt apically, not reaching apex of antennal sockets, flat dorsally; lateral ocelli present, circular; median ocellus present, circular.

Thorax. Pronotum surface smooth; humeral sinus of pronotum absent, lateral lobe 1.7–2 times wider than high; marginal fold of pronotum very narrow, smooth; anterior margin of pronotum flat, weakly concave when seen from above; metazona flat, posterior edge of metazona slightly raised, straight when seen from above; lateral carinae of pronotum well developed, forming smooth, well-defined edges ( Figs. 1 B, 2B). Prosternum unarmed; sternum flat. Thoracic auditory spiracle large, narrowly oval, its upper half hidden under pronotum, without any setation on inner margin.

Legs. Legs long and slender; tarsomeres 1 and 2 cylindrical, without lateral grooves. Front coxa armed with short, slender spine; front femur unarmed ventrally, in cross section round dorsally, flat ventrally; genicular lobes of front femur unarmed or at most armed with minute spine on anterior (inner) side only; front tibia with dorsal margins armed with minute spines; both ventral margins also armed; apex of front tibia with 1 pair of dorsal and 1 pair of ventral spurs; ventral spines on front tibia short, about half as long as tibia diameter. Tympanum bilaterally open, oval, about twice as long as wide. Mid femur unarmed ventrally; genicular lobes of mid femur unarmed or at most armed with minute spine on anterior (outer) side only; mid tibia not noticeably thickened in basal part; armed dorsally on both margins with small spines; apex of mid tibia with 1 pair of dorsal and 1 pair of ventral spurs. Hind femur slender but distinctly thickened in basal half, unarmed ventrally; genicular lobes of hind femur unarmed; dorsal spines of hind tibia of equal size on both edges; consecutive spines of similar size; apex of hind tibia with 1 pair of dorsal and 1–2 pairs of ventral spurs.

Wings. Tegmen reduced, slightly shorter to slightly longer than pronotum; fully exposed, not covered by pronotum ( Figs. 1 B, 2B); anterior margin weakly rounded; female tegmen not reaching to slightly surpassing posterior margin of 1st abdominal tergite, overlapping; rounded apically ( Figs. 1 H, 2H). Costal field not dilated at base; left stridulatory area with large, poorly defined mirror; right stridulatory area with large, often partially pigmented but fully developed mirror. Stridulatory file flat, weakly bent; posterior margin of female tegmen with several short stridulatory files nearly perpendicular to M ( Figs. 1 I, 2I); hind wing reduced, half as long as tegmen but with still discernible venation.

Abdomen. Tenth tergite unmodified; epiproct unmodified, rounded; paraprocts unmodified. Cercus cylindrical, slightly bent inwards when seen from above; straight when seen from side; with apical tooth ( Figs. 1 E, 2E). Phallus entirely membranous, without sclerotized elements. Subgenital plate elongate, narrowly trapezoidal, with deep, triangular incision; styli absent; female subgenital plate widely triangular or rounded apically.

Ovipositor. Ovipositor curved, slightly longer than pronotum; apex rounded, with strong apical teeth on both valvulae, dorsal edge of upper valvula parallel to lower valvula ( Figs. 1 G, 2G).

Egg. Egg oval; flattened.

Coloration. Coloration green; legs and pronotum often with darker markings; tegmen often with dark brown or black patches; female tegmen often with dark apical spot.

Diagnostic remarks. The genus Austrodontura can be separated from all other African brachypterous Phaneropterinae by the presence of a distinct, sharp spine on the dorsal surface of the front coxae. The presence of this spine is not unique to the genus as many Phaneropterinae genera also have it, but the spine is not known to be present in any other brachypterous forms. Austrodontura also displays well-developed ocelli, structures frequently reduced in non-flying insects. This, and the fact that these insects still have remnants of the hind wings with recognizable venation, may suggest that the wing reduction in this genus has been a relatively recent event.

In addition to the above characters, Austrodontura can be differentiated from other brachypterous genera by the following: from Atlasacris it differs in the lack of inflated lateral lobes of the pronotum in the male and normally developed apical spines of the mid tibiae; from Peropyrrhicia it differs in the flat male subgenital plate, the lack of the modification of the male 10th abdominal tergite, and apically rounded ovipositor; from Monticolaria it differs in the shape of the ovipositor, the lack of a modified spur on the apex of mid tibia in the male, and a greater reduction of the tegmina; from Odonturoides is differs in the lack of modified spurs on the apex of mid tibia and the presence of well-developed lateral carinae of the pronotum; from Brinckiella it differs in the presence of tegmina in the female (females of all species of Brinckiella are apterous), the shape of the ovipositor, and the lack of styli on the subgenital plate of the male; and from Odontura it can be distinguished by the well-developed lateral carinae of the pronotum (lateral carinae are weakly developed only in O. maroccana Bolivar, 1908 ) and the shape of the ovipositor, which is proportionately distinctly longer and less curved in Odontura than in Austrodontura .

In the Eastern Cape Austrodontura is found in open or semi-open habitats with dense herbaceous vegetation. It seems to prefer microhabitats with high relative humidity, such as shaded thickets at the edges of coastal forests. Individuals were found on the vegetation ranging from the ground level (such as small clumps of grass) to about 3– 4 m above the ground on Acacia trees. Feeding activity on leaves and buds of a variety of plants was observed both during the day and at night, but stridulation was recorded only at night. The presence of multiple, short stridulatory files in the females indicates that these katydids probably exhibit courtship duetting, which has been documented in many other brachypterous Phaneropterinae (e.g., Heller 1990, Dobler et al. 1994).

Based on our field observations and the limited number of specimens present in museum collections it appears that species of Austrodontura reach maturity between January and March, and no specimens have been collected between April and late December. These insects have a patchy distribution, and may be present in high numbers at one location, but be completely absent from another location with similar vegetation just a few kilometers away, which may explain their general absence from South African entomological collections.

Figures

FIGURE 1. Diagnostic characters of Austrodontura capensis (Walker): A. male; B. male pronotum and tegmina, dorsal view; C. female; D. female pronotum and tegmina, dorsal view; E. male cerci and subgenital plate; F female subgenital plate; G. ovipositor; H. male right tegmen; I. female, ditto; J. female stridulatory files; K. male stridulatory file.