Monseremus appendiculatus Ingrisch, 2018

Tan, Ming Kai, Japir, Razy, Chung, Arthur Y. C. & Robillard, Tony, 2022, A review of the genus Monseremus Ingrisch, 2018 (Orthoptera, Stenopelmatoidea Gryllacrididae) from Borneo, Zootaxa 5165 (1), pp. 107-114 : 109

Monseremus appendiculatus Ingrisch, 2018

( Figs 1 , 2A–C , 3A, 3B , 4 )

Monseremus appendiculatus Ingrisch, 2018: 222

Monseremus appendiculatus — Cadena-Castañeda 2019: 79

New material examined. EAST MALAYSIA: • 1♂; Sabah, Mount Silam, near Lahad Datu ; N4.96816, E118.17191, 735.7± 9.4 m.a.s.l.; on foliage of bamboo; 12 May 2022, 21h30; coll. M. K. Tan, T. Robillard & R. Japir (SBH.22.34, FRC) • 1♀; Sabah, Mount Silam, near Lahad Datu ; N4.96878, E11.17189, 736.1± 5.4 m.a.s.l.; on foliage near ground; 12 May 2022, 21h56; coll. M. K. Tan, T. Robillard & R. Japir (SBH.22.39, FRC) • 1♂; Sabah, Mount Silam, near Lahad Datu ; N4.96800, E118.17189, 720.8±8.0 m.a.s.l.; on foliage; 12 May 2022, 23h00; coll. M. K. Tan, T. Robillard & R. Japir (SBH.22.45, ZRC) • 1♀; Sabah, Mount Silam, near Lahad Datu ; N4.96858, E118.17159, 727 m .a.s.l.; on foliage; 12 May 2022, 22h00; coll. M. K. Tan, T. Robillard & R. Japir (TR22-7, MNHN) .

Revised diagnosis. The male differs from that of Monseremus bellus comb. nov. by the medial processes of the tenth abdominal tergite: the inner margins and apices clearly separated (instead of touching each other). The female differs from that of Monseremus bellus comb. nov. by the lateral projections at the anterior margin of the subgenital plate larger, more bulbous (in lateral view), and longer in length than subgenital plate. Other minor differences include the male subgenital plate more squarish, ca. 1.7 times wider than long; ovipositor>17.0 mm in length, longer than in Monseremus bellus comb. nov.

Description of the males. Habitus and colouration similar to female described in Ingrisch (2018) ( Fig. 4A ). Four stridulatory files on first and second abdominal tergites, two on each tergite ( Fig. 4B ): Anterior file on first tergite short with 5 peg-like teeth (n = 2♂). Second file, also on first tergite, longer, more than twice the length of anterior file, slightly curved, with 12–13 peg-like teeth (n = 2♂). Third file on second tergite angularly curved, with 15–17 peg-like teeth (n = 2♂); teeth more densely packed than second file; posterior file on second tergite nearly straight, with 16–17 peg-like teeth (n = 2♂). Second and posterior files of subequal length. Eighth abdominal tergite enlarged, longer than other tergites ( Figs 4C, 4D ). Ninth abdominal tergite forming a hood ( Fig. 4D ). Tenth abdominal tergite with two processes in the middle; each process broadest at the base, triangular, pointing ventrally and produce into a sclerotized and obtuse apex ( Fig. 2C ); the process not touching each other at the apex ( Fig. 2C ). Epiproct concealed beneath tenth abdominal tergite ( Fig. 2C ). Cercus long and slender, cylindrical and setose, curved internally at the posterior end, with acute apex ( Fig. 2C ). Subgenital plate circa 1.7 times wider than long; anterior margin broadly concave; lateral margin straight, with some setae; posterior margin slightly emarginated in the middle, laterally forming a lobe where stylus is inserted ( Fig. 2C ). Stylus short and stout, setose, with obtuse apex ( Fig. 2C ).

Measurements (in mm, n = 2♂). BL = 18.6–21.3, HL = 2.8, PL = 5.0–5.3, PW = 5.9–6.6, HFL = 13.1–15.0, HTL = 12.5–14.1.

Distribution. EAST MALAYSIA: Sabah (Mount Kinabalu; Mount Silam[new locality record])

Ecology. This species seems to restricted to highlands of 500–900 m.a.s.l. This species was not found in lowland forests of eastern Sabah that the authors have sampled in (i.e., Kawag Forest Reserve, Kabili Sepilok Forest Reserve and Tabin Wildlife Reserve ) .

Figures

FIGURE 1. Monseremus appendiculatus in its natural environment in Mount Silam, Sabah.

FIGURE 2. Monseremus appendiculatus (A–C) and Monseremus bellus (D–F): female subgenital plate in ventral (A, D) and lateral (B, E) views; male abdominal apex in ventral view (C, F). Scale bars: 1 mm.

FIGURE 3. Monseremus appendiculatus (A, B) and Monseremus bellus (C, D): female abdominal apex in posterior view (A, C); female stridulatory files on second and third tergites (B, D). Scale bars: 1 mm.

FIGURE 4. Monseremus appendiculatus male: body in lateral view (A); stridulatory files on second and third tergites (B); abdominal apex in dorsal (C) and lateral (D) views. Scale bars: 5 mm (A); 1 mm (all except A).