Duolandrevus Kirby, 1906

Ma, Libin, Gorochov, Andrej V. & Zhang, Yalin, 2015, A new species of the genus Duolandrevus (Orthoptera: Gryllidae: Landrevinae) from China, Zootaxa 3963 (3), pp. 443-449 : 445

Genus Duolandrevus Kirby, 1906

Type species. Gryllus brachypterus Haan, 1842 (Java)

Notes. This genus is a most usual genus for this tribe. It is widely distributed in Southeast Asia (excepting Indian Subcontinent and Sri Lanka I.) and the Papuan Region (New Guinea and adjacent islands). Duolandrevus is characterized by the following set of characteristics: body is slightly or significantly depressed dorsoventrally; head is wide but not high, with an angular or rounded rostral projection in the profile; pronotum is transverse, without ridges along lateral edges of the disc; male tegmina are shortened and with developed stridulatory apparatus, but sometimes this apparatus is slightly reduced or almost lost; female tegmina are from distinctly shortened to scale-like and always without stridulatory apparatus; hind wings are from strongly shortened to absent; male metanotal gland is developed; legs are strong but not long, with two (inner and outer) tympanal openings in the fore tibia (but sometimes these openings or one of them may be lost), with denticles or unarticulated spines situated proximad to the longer articulated spines of this tibia, and with laterally compressed (not widened) second tarsal segments; male genitalia are with a large but not very long epiphallus deeply bifurcated in the posterior part and having a pair of additional posteromedial lobules (sometimes almost fused with each other) between the larger or longer posterolateral lobes, with rather small and compact ectoparameres partly articulated or fused with the epiphallic posterolateral lobes, with normal endoparameres having a median bridge and rather long apodemes, with short and almost membranous or indistinct rachis (= guiding rod), with a small formula (= mold of spermatophore attachment plate), and with a distinctly sclerotized rami; ovipositor is more or less long, straight, and without drilling denticles on the apical part.

Duolandrevus is divided into eight subgenera separated from each other morphologically and more or less geographically. These subgenera and some data on their distributions are given below, in a preliminary key to the Duolandrevus subgenera. However, this key may be significantly modified in the future because many new species must be discovered in the enormous unstudied or almost unstudied regions of Southeast Asia and on numerous islands between Asia and Australia, and some described species are in need of restudy, e.g. subgeneric position is quite uncertain in D. luzonensis Otte, 1988 , D. balabacus Otte, 1988 and D. gingoogus Otte, 1988 from the Philippines as well as in D. palauensis Otte, 1988 from a small island situated between the Philippines and New Guinea ( Otte, 1988).