Bioacoustics of Gibboryctes

Generic redescription Length : 21.0– 35.6 mm . Width : 11.0– 16.9 mm . Poorly apparent sexual dimorphism; body elongated, oval in dorsal view, convex in lateral view; dorsal surface nearly completely glabrous; ventral surface densely setose. Colour : From dark reddish brown to dark. Head : Transverse, about 2 times wider than long. Clypeus triangular, short, about 4 times wider than long, slightly narrow laterally, anteriorly acute; surface coarsely rugose, with scattered setae on each side. Frontoclypeal suture with a short, transverse, sometimes emarginate, subtrapezoidal tubercle. Frons from flattened to slightly concave; from rugopunctate to densely punctate. Ocular canthus rectangular, transverse, glabrous. Antennae : Provided with 10 segments; club short, globular, subequal in length to antennomeres II–VII combined; club decreasing in size from basal to apical lamella. Mouthparts : Labrum from trapezoidal to parabolic in shape. Mandibles with 2 rounded teeth (1 apical, 1 subapical) on outer margin; teeth projected forward beyond clypeus in dorsal view, strongly reflexed above clypeus in lateral view; subapical tooth slightly backward produced, larger in size compared to apical tooth. Maxillae with small teeth at inner margin of galea; stipe produced laterally in triangular shape. Labium oval, densely covered with bristled punctures. Thorax : Pronotum weakly convex in lateral view; horn absent, but with a small tubercle located at middle area contiguous to anterior margin; dorsal surface nearly completely covered with dense, large, deep, ocellated punctures; discal area covered with large, coalescent punctures, sometimes longitudinally scattered along of a middle line; anterior and lateral borders complete, posterior usually incomplete. Scutellar plate from subtriangular to parabolic, bearing irregularly scattered punctures. Elytral surface with 8 wellmarked striae longitudinally (4 discal, 4 lateral); striae covered with a row of large, ocellated, deep punctures; interstriae with mixed fine and large punctures. Legs : Protarsi with scytheshaped claws; tarsomere V clavate, elongated, 2 times longer than tarsomere IV; tarsomeres I–IV ‘beaker’-shaped, subequal in length. Protibial outer margins with 4 teeth (1 apical, 2 medial, 1 basal); apical tooth triangular, curved, pointed; medial and basal teeth triangular; basal tooth smaller than previous ones; dorsal surface weakly punctate, longitudinally covered with a double row of bristled punctures. Mesotarsi similar to metatarsi, with tarsomeres I–IV gradually decreasing in size. Meso- and metatibiae cylindrical in shape, with 2 transverse carinae on outer surface (1 basal, 1 medial); carinae and apex weakly crenulated, covered with stout spinules like-setae; inner surface moderately covered with long bristles. Abdomen : Tergite VII lacking stridulatory apparatus. Tergite VIII transverse, subtriangular, strongly convex in lateral view in male; surface glabrous, rugopunctate on sides, densely covered with large, deep punctures on discal area. Ventrites II–VI coarsely rugopunctate on sides, finely punctate and glabrous on discal area; ventrites III–V with an incomplete row of setigerous punctures confined on sides; posterior margin of ventrite VI emarginate, setose. Aedeagus : Parameres, in dorsal view, symmetrical, basal half clearly wider than apical half, inner margin weakly bristled on apex. Parameres, in lateral view, 1.5 times shorter than phallobasis, dorsal surface convex, ventral surface with a weakly downward-produced carina at middle. Sexual dimorphism The two sexes are largely identical, but the female can be distinguished in the following aspects: Head : Anterior clypeal margin rounded. Abdomen : Tergite VIII flattened in lateral view; ventrite VI parabolic, lacking posterior emargination. Specific composition

Notes on natural history of Gibboryctes Specimes of Gibboryctes szelenyii and G. endroedii sp. nov. were collected inside of epigeous termite nests ( Blattodea :Isoptera: Termitidae ). Gibboryctes szelenyii was found to be associated with many termite species (see remarks under G. szelenyii ). Termites were not collected from the nests where specimens of G. endroedii were found. The localities of nests are marked by shrub vegetation and rocky outcrops characteristic of open areas of savannah and rupestrian grasslands ( Figure 15 (a,b)). Adults, pupae and larvae of G. szelenyii and G. endroedii sp. nov. were found occupying the central portion of nests ( Figure 16 (a–d)). When handled, the larvae emitted a stridulation sound produced by friction among the mandibles and maxillae. Furthermore, the larvae were observed building rigid galleries structured with faeces and saliva.The pupal chamber is also quite rigid,perhaps to avoid termite attacks ( Figure 16 (c)).The larval excrement, when dried, acquires a peculiar aspect similar to ‘pellets’, flattened and subrectangular, with almost straight corners (90-degree angles),and which can be considered a diagnostic character for generic identification. This discovery represents the first record of an Oryctini associated with a termite nest. Regarding G. ebeninus sp. nov. , only adults were collected, in an area under a Eucalyptus crop where a Pennsylvania light trap was installed, which perhaps attracted the specimens.