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[A, B, D] Nisitrus malaya Robillard & Tan sp. nov. [E, F, G] N. vittatus (Haan, 1844). in Tan, Wahab, Japir, Chung et Robillard. 2021. Photograph: Ming Kai Tan. |
ABSTRACT
Nisitrus Saussure, 1878 is a diurnal and monophyletic group of eneopterine crickets found in parts of Southeast Asia. Species often have vivid colourations which make them charismatic photograph subjects among macro photographers. However, their taxonomy has not been revised since their original descriptions, whereas there are also species awaiting to be discovered and described. A synoptic revision is therefore needed prior to studying the phylogenetic relationships of the genus, and before undertaking more precise studies on biogeography and evolution of traits. By holistically incorporating information about general morphology, male and female genitalia, and bioacoustics, we revise the taxonomy of these crickets and recognise 10 valid species of Nisitrus. Five new species are described: N. crucius Robillard & Tan sp. nov. from Borneo; N. danum Robillard & Tan sp. nov. from Borneo; N. hughtani Robillard & Tan sp. nov. from Sumatra; N. malaya Robillard & Tan sp. nov. from Malay Peninsula; and N. rindu Robillard & Tan sp. nov. from Borneo. We redescribe N. brunnerianus and N. insignis; describe the calls of N. malaya sp. nov., N. musicus and N. vittatus. We consider N. sumatrensis as a junior synonym of N. insignis; and N. marginata as a junior synonym of N. vittatus. Nisitrus hyalinus requires further revision. We also consider N. maculosus as a dubious name.
Keywords: Nisitrini, key, lectotype, redescription, Southeast Asia
Class Insecta Linnaeus, 1758
Order Orthoptera Latreille, 1793
Suborder Ensifera Chopard, 1920
Superfamily Grylloidea Laicharting, 1781
Family Gryllidae Laicharting, 1781
Subfamily Eneopterinae Saussure, 1874
Tribe Nisitrini Robillard, 2004
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| A–D. Nisitrus malaya Robillard & Tan sp. nov. E–H. N. vittatus (Haan, 1844). Adult ♂♂ (A–B, E–F) and ♀♀ (C–D, G–H) in their natural environment. Photograph: Ming Kai Tan. |
Genus Nisitrus Saussure, 1878
Type species: Nisitra vittatus (Haan, 1844).
Remarks on type species: Kirby (1906) and Chopard (1968) listed N. vittata as the type species of Nisitra and treated the original type species N. marginata Walker, 1869 as a synonym of N. vittata. Subsequent authors listed N. vittatusas the type species of the replacement name Nisitrus, although Otte (1994) reinstated N. marginatus as a valid species (Braun 2013 in Cigliano et al. 2020). The present revision revalidates the synonymy of N. marginatus under N. vittatus, making N. vittatus the valid type species of the genus.
Diagnosis (emended from Robillard & Tan 2013) Among genera of Eneopterinae, Nisitrus is characterised by an elegant, wasp-like, slender and colourful body (Figs 7–9). Size average for subfamily. Colouration vivid, dominantly yellow, whitish and black, with species-specific patterns, particularly in the head (Figs 10–11), pronotum (Figs 11–12) and FWs (Figs 12–14). Characteristic head shape with narrow fastigium and large prominent eyes with thin dorso-ventral black stripes. Pronotum setose, square-shaped to slightly trapezoidal, usually bisinuated posteriorly. Metanotum with large glandular structures in males, made of a wide pit on scutum and a pair of posterior pits on scutellum, with glandular pores mostly organised by groups of 2 or 3 (Fig. 15). FWs more or less as long as abdomen. Male Nisitrus show modified FW venation and characteristic glossy transparency. Hindwings longer than FWs, bicoloured in most species, their base transparent with a wide dark posterior margin. Legs long and thin, FIII with a characteristic narrowed area before knee. Other general traits: TI with two tympana, inner one slit-like, covered by a swollen cuticular expansion; outer tympanum oval, its membrane transversally plicate in dorsal half. TI with three apical spurs; outer dorsal spur missing. TII with four apical spurs, inner longest. TIII with three inner and three outer apical spurs, median longest on each side; four pairs of subapical spurs, inner and outer spurs almost straight, their apex hook-like; TIII serrulate over whole length, slightly furrowed dorsally. Tarsomeres III-1 with one row of dorsal spines on external edge in addition to apical spines. Apical claws of legs slightly indented. Both males and females show characteristic genitalia.
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| Nymphs in their natural environment. A–C. Nisitrus malaya Robillard & Tan sp. nov. D–F. N. vittatus (Haan, 1844). Photograph: Ming Kai Tan. |
Ming Kai Tan, Rodzay bin Haji Abdul Wahab, Razy Japir, Authur Y.C. Chung and Tony Robillard. 2021. Revision of the Cricket Genus Nisitrus Saussure (Orthoptera: Gryllidae: Eneopterinae) and Descriptions of Five New Species. European Journal of Taxonomy. 761(1), 1-75. DOI: 10.5852/ejt.2021.761.1449
