Ornebius Guérin-Méneville, 1844

Hegg, Danilo, 2024, Small crickets of New Zealand (Orthoptera: Grylloidea: Trigonidiidae and Mogoplistidae), with the description of two new genera and species, European Journal of Taxonomy 955 (1), pp. 1-87 : 21-22

Identification of Ornebius Guérin-Méneville, 1844 by sound

Ornebius sound recordings taken in Auckland, Coromandel, Waikato and in New Plymouth yield a song with a peak frequency between 4.5 and 5.6 kHz. Chirps are approximately one second apart and consist of three pulses; a single pulse followed by a pause of 0.3 seconds then two more pulses close together ( Fig. 34 ). This song matches that of Ornebius aperta ( Otte & Alexander 1983: fig. 314; Gwynne et al. 1988). As previously observed by Ramsay (1990, 1991), the paraprocts are also a good match for Ornebius aperta , club-like in shape, narrowest at the base and widest one fifth of the length from the apex ( Fig. 33G–I ).

Ornebius crickets around Whangārei and Kerikeri in Northland sing at a peak frequency of 4 kHz (T = 23°C). Chirps are approximately two seconds apart and consist of four to five pulses; a single pulse followed by a pause longer than half a second then three to four pulses close together ( Fig. 35 ). This song does not match any known species of Ornebius . The male paraprocts are subtly different from those of O. aperta , with a longer narrow neck at the base, and the widest point one fourth of the length from the apex ( Fig. 33K ). While this shape may resemble more closely the paraprocts of Ornebius wandella Otte & Alexander, 1983 , the latter species has two very prominent hair tufts projecting backwards from the posterior margin of the suranal plate ( Otte & Alexander 1983: fig. 312y); these are missing in Ornebius aperta and in Ornebius crickets from Northland ( Fig. 33D–E ). Except for the subtle difference in the shape of the male paraprocts, male and female Ornebius crickets from Northland cannot be differentiated from Ornebius aperta by morphology.

Based on this information, Ornebius crickets from Northland might be a species other than Ornebius aperta , but I am not confident enough to state that they definitely are, let alone to designate a new species. This really needs to be done in the context of a comprehensive revision of Ornebius from the east coast of Australia and from the wider Pacific region, based on morphology, song and molecular data. I will therefore refer to the Ornebius population in Northland as Ornebius aff. aperta Otte & Alexander, 1983 , where the abbreviation ‘aff.’ is used as suggested by Sigovini et al. (2016).

The boundary between the Auckland and Northland Ornebius populations is unknown.

Figures

Fig. 34. Ornebius aperta Otte & Alexander, 1983 song, recorded in captivity at 20°C. Tahuna Torea Reserve, Auckland. A. Spectrogram of a sequence of three chirps. B. Oscillogram of a sequence of three chirps. C. Oscillogram of one chirp consisting of three pulses. D. Power spectrum of one chirp.

Fig. 33. Ornebius aperta Otte & Alexander, 1983 (O.a.) and Ornebius aff. aperta Otte & Alexander, 1983 (O. aff. a.). All specimens stored at MPN. A–B. Head, lateral and frontal view, adult ♀. O. aff. a., Whangārei (OR0306). C. Dorsal view of forewing, adult ♂. O.a., Auckland (OR0294). D–E. Dorsal view of terminalia, O.a. adult ♂. D. Tamborine Mtn, QLD. Drawing from Otte & Alexander (1983: fig. 312e’). E. Auckland (OR0294). F. Left tympanum. O.a., Auckland (OR0294). G–I. Lateral view of paraprocts, O.a. adult ♂. G. Tamborine Mtn, QLD. Drawing from Otte & Alexander (1983: fig. 312p). H–I. Auckland. H. OR0294. I. OR0295. J. Dorsal view of genitalia. O. aff. a., adult ♂. Kerikeri (OR0298). K. Lateral view of paraprocts, O. aff. a., adult ♂. Kerikeri (OR0299). L. Egg. O. aff. a., Kerikeri (OR0381). M. Dorsal view of ovipositor tip. O. a., Auckland (OR0289). N. Lateral view of ovipositor. O. aff. a., Whangārei (OR0307). Black scale bars = 500 μm; white scale bar = 100 μm.

Fig. 35. Ornebius aff. aperta Otte & Alexander, 1983 song, recorded in the field at 23°C. Lane Cove, Northland. A. Spectrogram of a sequence of two chirps. B. Oscillogram of a sequence of two chirps. C. Oscillogram of one chirp consisting of five pulses. D. Power spectrum of one chirp.