Gonatoxia helleri Hemp 2016

Gonatoxia helleri Hemp, 2016

http://lsid.speciesfile.org/urn:lsid: Orthoptera.speciesfile.org:TaxonName:492596

(Figs. 32 E–J, 54A–C)

Diagnostic remarks. G. helleri is a large, leaf-like katydid with wide wings that are often marked with white or light brown spots (more frequently in males than females) (Figs. 32H, I), bright yellow dorsal surface of the abdomen, and the male cerci that are weakly incurved and carry fine, dark brown serration at their tips (Figs. 32E, F). From other members of the genus Gonatoxia Karsch, 1889 this species can be distinguished by the shape of the cercus and the structure of the stridulatory file, which features a prominent “dip at its distal end (Fig. 32G).

Bioacoustics. G. helleri has an interesting acoustic behavior, recently described by Heller & Hemp (2017). In this species the male occasionally adds an additional, low frequency (9 kHz) syllable to his call. He does it in an apparent effort to mimic the call of the female of the same species, whose call has a similar frequency. This, presumably, makes it more difficult for other males to locate the female who is responding to the signal of the original caller and lowers their chances of mating. The call of this species in the Gorongosa population consists of paired syllables with the mean duration of 0.00523 (SD=0.00072, n=13) and peak frequency of 16.9–18.1 kHz (Figs. 54 A–C).

Distribution and natural history. This species was only recently described from Tanzania and Kenya (Hemp et al. 2016) but it is also quite common in Gorongosa and surrounding areas. It is found in forested areas, including tall, closed-canopy miombo woodland. It is a canopy inhabitant and can only be seen when attracted to artificial lights.

Measurements (3 males, 7 females). — body w/wings: male 46–46.5 (46.2.3), female 45–51.4 (48.82); body w/o wings: male 25–26 (25.3.6), female 26–31 (29.31.8); pronotum: male 4–5.5 (4.8.8), female 5–5.5 (5.2.3); tegmen: male 34–35 (34.5.5), female 34.5–37.5 (36.61.1); hind femur: male 21–23.5 (22.21.3), female 22–23.9 (22.9.6); ovipositor: 5–6 (5.5.4) mm.

Material examined (13 specimens). Mozambique: Sofala, Gorongosa, GNP, Bela Vista ranger outpost, elev. 26 m (-18.69470, 34.20853), 5–12.v.2015, coll. P. Naskrecki— 1 female; GNP, Chitengo, Wilson Laboratory, elev. 48 m (-18.977722, 34.351333), 15–31.xii.2017, coll. N. Vicente— 1 female; Gorongosa Dist., Wilson Laboratory, GNP, Chitengo, (-18.97775, 34.351333), 21.vii.–8.viii.2015, coll. B. Woo— 2 females; GNP, Chitengo, elev. 28 m (-18.98, 34.352639), 30.i.–12.ii.2014, coll. P. Naskrecki— 1 male (EOWL); GNP, Chitengo, elev. 29 m (-18.98194, 34.35122), 30.i.–13.ii.2014, coll. P. Naskrecki— 1 male; GNP, nr. Chitengo, humid forest along road to sanctuary, elev. 29 m (-18.99122, 34.32811), 16–23.v.2012, coll. P. Naskrecki— 1 female (MCZ); GNP, along Pungue Rd, nr. Vinho Rd., elev. 25 m (-18.99675, 34.365806), 11–16.vi.2014, coll. P. Naskrecki & R. Guta— 1 male (EOWL); GNP, nr. Nhascuvo outpost, (-19.062639, 34.232194), 24–28.vi.2014, coll. G. Daniel, I. Nganhane & R. Guta— 1 female (UEMM); GNP, Urema Rd., first bridge, elev. 28 m (-18.993861, 34.383722), 15.vi.2014, coll. P. Naskrecki & R. Guta— 1 female (EOWL); Waterfall Camp, (-19.03087, 34.67635), 22.iii.2013, coll. P. Naskrecki— 1 female; same locality, 22.iii.2013, coll. P. Naskrecki— 1 female (EOWL, MCZ); Sofala Prov., Bela Vista Camp, (-18.695083, 34.209389), 6.v.2015, coll. T. Massad— 1 female (EOWL).