Nisitrus danum Robillard & Tan, 2021

Tan, Ming Kai, Wahab, Rodzay bin Haji Abdul, Japir, Razy, Chung, Authur Y. C. & Robillard, Tony, 2021, Revision of the cricket genus Nisitrus Saussure (Orthoptera: Gryllidae: Eneopterinae) and descriptions of five new species, European Journal of Taxonomy 761 (1), pp. 1-75 : 31-33

Nisitrus danum Robillard & Tan sp. nov.

urn:lsid:zoobank.org:act:0DEB5BDB-6E85-4691-B5D1-E6258239370A

Figs 5 , 8D , 10C , 11C , 12C , 14C , 17E , 19; Tables 2 , 5

Diagnosis

This new species differs from all known congeners by face part of fastigium with a black band across eyes and antennal cavity, frons otherwise yellow (reddish on preserved specimens); pronotal lateral lobe black dorsally and yellow ventrally; longitudinal white stripe only between M and R and lateral field matted black; Sc projections black. This new species is most similar to N. hughtani sp. nov. from Sumatra, but differs by the following characters: smaller in size, vertex black with yellow margin around eyes (instead of cream-coloured), frons with a black band across eyes and antennal cavity (yellow in N. hughtani sp. nov.); frons yellow (instead of black with a cream-coloured band ventral to eyes); mouthparts yellowish with some black spots; lateral part of head with a black band posterior of eye (instead of black with a cream-coloured ring around eye). This species is also similar to N. musicus from Kinabalu range, but differs by mouthparts yellow (instead of black), FIIIs not black dorsally, female papilla, and distribution: N. musicus is restricted to the highlands in the Kinabalu range, while N. danum sp. nov. occurs in the Danum Valley and Tawau Hill areas at the east of Sabah.

Etymology

The specific name is a noun in apposition taken from the type locality, Danum Valley, Malaysia.

Material examined

Holotype MALAYSIA – Sabah • ♀; Danum Valley Field Centre; 4°57′52.95″ N, 117°48′18.25″ E; ca 150 m a.s.l.; 26 May–20 Jun. 1987; C. v. Achterberg and Kennedy leg.; PII: N54; RMNH.

Paratypes MALAYSIA – Sabah • 1 ♀; same collection data as for holotype; RMNH • 1 ♀; same collection data as for holotype; MNHN-EO-ENSIF10945 .

Additional specimens

MALAYSIA – Sabah • 1 ♀; Tawau Hill Park ; 4°24′0.0″ N, 117°53′24.0″ E; 7 Mar. 2018; C. Elder leg.; iNaturalist.org/observations/19511712 • 1 ♀; Danum Valley ; 4°57′42.6″ N, 117°41′22.2″ E; 2 Oct. 2020; L. Day leg.; iNaturalist.org/observations/21010925 .

Description

Slender and relatively large habitus ( Figs 8D , 19 ). Vertex black with yellow margin around eyes ( Fig. 11C ). Fastigium velvety black with yellow margins. Scapes dark red brown to black (particularly on the dorsoinner margins). Antennae black with wide whitish rings. Face part of fastigium with a black band across eyes and antennal cavity, otherwise yellow (reddish in preserved specimens); frons almost entirely yellow, including mouthparts, with some black spots ( Fig. 10C ). Maxillary palpi cream-coloured; apical segment black apically ( Fig. 10C ). Lateral part of head with a black band posterior to eye ( Fig. 12C ). Pronotum covered with white setae; dorsal disk dark brown to black ( Fig. 11C ). Lateral lobes of pronotum dorsal third black, vivid yellow ventrally (cream-coloured in preserved specimens) ( Fig. 12C ). Legs generally red brown, sometimes dorsally darker. FIIIs brown, knees dark brown to black; TIIIs brown with black spines and spurs, dark brown to black near distal end; tarsomeres dark brown to black. Tergites red brown, with a pale band laterally; sternites pale, with red brown median area. Cerci red brown, short and conical.

Male

Unknown.

Female FOREWINGS. FW colouration ( Fig. 14C ): veins generally yellow; cells infumated black. Longitudinal

infumated white stripe only in M and R. Lateral field matted black, Sc projections black. FW venation: 6–7 strong longitudinal veins on dorsal field, cross-veins irregular and often sinuous; lateral field with 6 projections of Sc.

GENITALIA. Ovipositor: distinctly longer than FIII; apex thin with both dorsal and ventral edges smooth. Copulatory papilla conical, smaller and stout; apex strongly folded (could be due to the preservation of specimen) ventrally, short, pointed; dorsal face with a sclerotized area ( Fig. 17E ).

Juvenile

Unknown.

Measurements

See Table 5 .

Ecology

Unknown.

Distribution

Borneo (Sabah).

Type locality

Malaysia: Sabah.

Calling song

Unknown.

Figures

Fig. 5. Map of Southeast Asia showing the distribution of species of Nisitrus Saussure, 1878. Each coloured symbol represents one sampling or observation locality listed in the material in the text.

Fig. 8. Habitus of ♀♀ in dorsal view. A–B. Nisitrus brunnerianus Saussure, 1878. C. N. crucius Robillard & Tan sp. nov. D. N. danum Robillard & Tan sp. nov. E. N. hughtani Robillard & Tan sp. nov. F. N. insignis Saussure, 1878. Scale bar = 10 mm.

Fig. 10. Face in anterior view. A. Nisitrus brunnerianus Saussure, 1878. B. N. crucius Robillard & Tan sp. nov. C. N. danum Robillard & Tan sp. nov. D. N. hughtani Robillard & Tan sp. nov. E. N. insignis Saussure, 1878. F. N. malaya Robillard & Tan sp. nov. G. N. musicus Ingrisch, 1987. H. N. rindu Robillard & Tan sp. nov. I. N. vittatus (Haan, 1844). Scale bar = 2 mm.

Fig. 11. Head and pronotum in dorsal view. A. Nisitrus brunnerianus Saussure, 1878. B. N. crucius Robillard & Tan sp. nov. C. N. danum Robillard & Tan sp. nov. D. N. hughtani Robillard & Tan sp. nov. E. N. insignis Saussure, 1878. F. N. malaya Robillard & Tan sp. nov. G. N. musicus Ingrisch, 1987. H. N. rindu Robillard & Tan sp. nov. I. N. vittatus (Haan, 1844). Scale bar = 2 mm.

Fig. 12. Body in lateral view. A. Nisitrus brunnerianus Saussure, 1878. B. N. crucius Robillard & Tan sp. nov. C. N. danum Robillard & Tan sp. nov. D. N. hughtani Robillard & Tan sp. nov. E. N. insignis Saussure, 1878. F. N. malaya Robillard & Tan sp. nov. G. N. musicus Ingrisch, 1987. H. N. rindu Robillard & Tan sp. nov. I. N. vittatus (Haan, 1844). Scale bar = 5 mm.

Fig. 14. Female tegmina in dorsal view. A. Nisitrus brunnerianus Saussure, 1878. B. N. crucius Robillard & Tan sp. nov. C. N. danum Robillard & Tan sp. nov. D. N. hughtani Robillard & Tan sp. nov. E. N. insignis Saussure, 1878. F. N. malaya Robillard & Tan sp. nov. G. N. musicus Ingrisch, 1987. H. N. rindu Robillard & Tan sp. nov. I. N. vittatus (Haan, 1844). Scale bar = 2 mm.

Fig. 17. Female genitalia in lateral (A, C, E, F, H, J, L, N, P) and dorsal (B, D, G, I, K, M, O, Q) views. A–B. Nisitrus brunnerianus Saussure, 1878. C–D. N. crucius Robillard & Tan sp. nov. E. N. danum Robillard & Tan sp. nov. F–G. N. hughtani Robillard & Tan sp. nov. H–I. N. insignis Saussure, 1878. J–K. N. malaya Robillard & Tan sp. nov. L–M. N. musicus Ingrisch, 1987. N–O. N. rindu Robillard & Tan sp. nov. P–Q. N. vittatus (Haan, 1844). Scale bar = 0.5 mm.

Fig. 19. Nisitrus danum Robillard & Tan sp. nov., adult ♀♀ in their natural environment. Photograph source and credits: iNaturalist; Arthur Anker (A), Charlie Elder (B).

Tables

Table 5. Measurements of Nisitrus danum Robillard & Tan sp. nov. (in mm, means in brackets).

	PronL	PronW	FWL	FWW	HWT	FIIIL	FIIIW	TIIIL
Female holotype	2.0	3.2	10.8	3.5	6.4	15.3	2.7	15.5
Females (n = 3)	2.0–2.3 (2.2)	3.2–3.5 (3.4)	10.8–11.7 (11.4)	3.5–4.2 (4.0)	6.4–7.7 (7.2)	15.3 (15.3)	2.7 (2.7)	15.5 (15.5)