Macroxiphus sumatranus ( Haan, 1843 )

Tan, Ming Kai, Muhammad, Amira Aqilah, Gorochov, Andrei V. & Abdullah, Nurul Ashikin, 2024, An account on some katydids (Orthoptera: Tettigonioidea) from Panti Forest Reserve in Johor, Peninsular Malaysia, Zootaxa 5415 (1), pp. 117-143 : 119-123

Macroxiphus sumatranus ( Haan, 1843)

( Figs 1–5 )

Locusta (Locusta) sumatranus Haan, 1843: 215 , 216.

Macroxiphus sumatranus ( Haan, 1843) — Ingrisch, 1998: 73

Specimens examined. PENINSULAR MALAYSIA: Johor State: PFR • 1♁; Panti Barat ; N1.80966, E103.85157, 66.9± 7.5 m.a.s.l.; 17 August 2023, 20h04; hiding inside dried, curled-up ginger foliage; coll. M. K. Tan, Amira A. Muhammad & N.Ashikin Abdullah; PANTI.23.18 (ZRC)

Remarks. The male collected from PFR ( Figs 1–3 ) appears to be morphologically more similar to Macroxiphus sumatranus sumatranus ( Haan, 1843) than Macroxiphus sumatranus siamensis Helfert & Sänger, 1995 by the shape of the titillators with its sclerites more elongated and curved (instead of right-angled) ( Figs 3D, 3E ); but the shape of the cercus is intermediate between the nominal subspecies from Indonesia and latter subspecies from Thailand ( Figs 3A–C ). Our male specimen has 108 teeth on the left tegmen, which is also intermediate between the two subspecies. Furthermore, the calling song of the male is more similar to that of the nominal subspecies. These variations suggest that characters used to define the subspecies may need to be reconsidered with the aid of examining more specimens from different parts of their distributions.

Ecology. Adult males, females and juveniles were found dwelling or hiding among dried ginger foliage ( Figs 1 , 4 ).

Type locality. INDONESIA: Sumatra: Padang

Distribution. INDONESIA (Sumatra); PENINSULAR MALAYSIA (Johor State: PFR) [new]

Calling song (1♁, 28.3°C) ( Fig. 5 ). The calling song is made up of a fairly isolated echeme, each consisting of two closely-spaced syllables. Each echeme has an average duration of 0.35±0.02 s (0.33–0.37 s). The first syllable has an average duration of 18.7±0.9 ms (17.6–19.9 ms) and an average period of 0.15±0.01 s (0.14–0.16 s). The second syllable has an average duration of 18.9±1.2 ms (17.8–20.7 ms). The interval between the two syllables has an average duration of 0.13±0.01 s (0.11–0.14 s). The call spectrum is broad-based and has a peak frequency of 11.7±1.0 kHz (10.8–13.4 kHz).

The calling song of the male from PFR consists of two syllables, similar to that of Macroxiphus sumatranus sumatranus (recorded from Maninjau from West Sumatra), whereas that of Macroxiphus sumatranus siamensis (recorded from Ulu Gombak in Selangor and Surat Thani in Thailand) typically consists of four syllables.

Figures

FIGURE 1. Macroxiphus sumatranus ♁ adult hiding among dried leaves.

FIGURE 2. Macroxiphus sumatranus head and pronotum in dorsal (A) and lateral (B) views, face in anterior view (C), stridulatory apparatus of the left tegmen in ventral view (D) and of the right tegmen in dorsal view (E). Scale bars: 1 mm (all except E), 2 mm (E).

FIGURE 3. Macroxiphus sumatranus ♁ abdominal apex in dorso-posterior (A), lateral (B) and ventral (C) views, titillators in dorsal (D) and ventral (E) views. Scale bars: 1 mm (A, D, E), 2 mm (B, C).

FIGURE 4. Macroxiphus sumatranus ♀ (A) subadult and juvenile (B) in their natural environment.

FIGURE 5. Macroxiphus sumatranus ♁ calling song recorded in the laboratory: oscillograms showing six isolated echemes (A) and one echeme (B), and spectrogram of the same echeme (C).