Microdebilissa bawangia, Tichý, 2024

Tichý, Tomáš, 2024, A new species of the genus Microdebilissa Pic, 1925 from West Kalimantan (Coleoptera, Cerambycidae, Cerambycinae, Stenopterini), Faunitaxys 12 (62), pp. 1-4 : 1-4

Microdebilissa bawangia sp. nov.

( Fig. 1-12)

ZooBank: https://zoobank.org/ 56275163-0FAA-417C-B734-942958DFCE5C

Holotype, ♂ ( CTT), Gunung Bawang , alt. 245 m, West Kalimantan Province, Indonesia, V. 2019.

Paratypes

- 4 ♂, 5 ♀, same data as the holotype .

- 10 ♂, 12 ♀, Gunung Bawang, Madi, alt. 1,000‒1,500 m, VI. 2018.

The holotype is provisionally placed in the collection of T . Tichý ( CTT), but after completing the revision of this group, it will be placed in a research institution of Indonesia. Paratypes are in the collections of CTT and CTN .

Reviewers:

Andreas Weigel ( Wernburg, Germany) - https://zoobank.org/ 7BB7974D-7ACF-4D0C-8699-C5839717F60A

Junsuke Yamasako ( National Agriculture and Food Research Organization, Japan) - https://zoobank.org/ 7D448A42-7C04-4718-B9DE-1B8C0C45250D

Description

Body length (from apical margin of frons to abdominal apex) 5.1–5.9 mm in male, 5.9–6.5 mm in female. Large and robust species of black body except for yellowish stripe near elytral base, with distinct serration of apical antennomeres and flattened pronotal disc.

Male

Generalmorphology. –Colourblack,matted, yellowishbrowninmouthparts except for mandibles, dark chestnut brown in antennae, venter of thoraces and legs; elytra black, with a broad light brown stripe on basal fifth or more on each elytron, the stripe narrowly extended posteriorly and sometimes reaching the middle and alsoexternalmargins behind humeri, supplemented with a small spot on each external margin near middle, but such spot sometimes missing, mostly with darker specimens. Body clothed with fine pale gray pubescence and partly with a few erect setae on front of head and base of pronotum; elytra almost glabrous except for short-setigerous punctures; ventral surface densely clothed with silvery white pubescence; femora sparsely covered with blackish setae; tibiae clothed with light brown pubescence on about apical 2/3.

Head ( Fig. 3). – Slightly narrower than the maximum width of pronotum, well convex, uniformly raised even in vertex, closely covered with fine reticulations; frons about half length of width, with frontoclypeal suture very shallow; tempora long, abruptly narrowed behind eyes, then almost parallel-sided; eyes moderately prominent. Antennae ( Fig. 7) clearly shorter than body, barely reaching apical sixth of elytra; antennomeres III‒IV almost same in length, weakly thickened apically; V‒X flattened, strongly dilated, obtusely serrate at each outer corner (particularly in VI‒IX); XI becoming narrower in apical fourth.

Pronotum ( Fig. 3, 4). – Subquadrate, nearly as long as wide, about 1/4 the length of elytra; sides weakly dilated posteriorly in an arcuate shape; base broadly and thickly constricted near the middle, slightly emarginate at the sides; disc uniformly convex and flattened above, except for a wide, deep arcuate concavity along the basal margin, closely and uniformly covered with fine, shallow reticulations.

Scutellum. – Triangular with deep emargination at apex.

Elytra ( Fig.4, 5). –Narrowand relativelylong, aboutthrice the length of humeral width; sides distinctly narrowed straight to middle then straightly dilated to just before apices, which are narrowly rounded, provided with small but conspicuous dents from humeri to apices; disc flattened, narrowly concave along suture behind scutellum, densely covered with relatively large punctures in irregular lines, the punctuation gradually sparser and shallower from apical halves, and scatteredwith fine punctures near apices.

Ventral surface. – Finely and shallowly reticulate on prosternum and mesothorax, sparsely punctured on metathorax; prosternal process parallel-sided, with large triangular apical part; abdomen microsculptured, with last ventrite almost transversely truncate at apical margin.

Legs. – Relatively long and stout, especially in hind pair; metafemora weakly clavate in apical 2/3; metatibia ( Fig. 9) moderately arcuate, provided with a pair of rows of small dent along whole external margin, with a pair of short terminal spurs.

Male terminalia. – Tergite VIII ( Fig. 10) ginkgo-leaf-shaped, deeply and narrowly emarginate at middle, with anterior margin strongly oblique, covered with fine and very short setae, inner angle of each lobe rounded, the setae somewhat longer only in this area. Parameres ( Fig. 11) very short; rounded at each apex, covering 6-7 semilong setae. Median lobe ( Fig. 12) short, spherical in dorsal view, rounded at apex, thick, beakshaped in lateral view, very shortly projected downward at tip; dorsal plate bilobed, divided laterally and intersecting dorsally, with sides linearly narrowed up to apical third, then tapering a slight arc towards subtruncate apex; median struts short, about half the length of median lobe.

8 9

3. Head and pronotum, dorso-lateral view. 4. Left basal parts of pronotum and elytra, dorsal view. 5. Apical parts of left elytron, dorsal view. 6. Abdominal ventrite, ventral view (arrow indicates rake organ on 2nd ventrite). 7 & 8. Left antennae, dorsal view. 9. Metatibia, dorsal view. 10. Abdominal segments VIII-IX, ventral view. 11. Tegmen (left: dorsal view; right: lateral view). 12. Median lobe (left: dorsal view; right: lateral view).

3 -5, 7 & 9. ♂, holotype. 6 & 8. ♀, paratype. 10 -12. ♂, paratype.

(Scales. 10 -12: 0.25 mm. 3 - 6: 0.5 mm. 7 -9: 2 mm)

Female. – Colour almost like in male, but ventral surface entirely dark chestnut brown including abdomen. Body shorter and broader than in male. Antennae ( Fig. 8) a little more than half length of body, reaching basal 2/5 of elytra; antennomeres V‒X not so strongly flattened and dilated as in male; XI short oval, bluntly pointed apically. Elytra weakly emarginate at sides. Rake organ ( Fig. 6; see Notes) well developed and occupied entire width of apical margin of 2nd ventrite.

Dimension ratios

Male (n = 2)

HW/PW 0.97, 0.98;

HW/PAW 1.18, 1.21;

PL/PW 0.93, 0.98;

PL/PAW 1.16, 1.18;

PBW/PAW 1.15, 1.18;

PL/EL 0.25, 0.26;

EL/EW 2.94, 2.99.

Female (n = 2)

HW/PW 1.00, 1.01;

HW/PAW 1.20, 1.28;

PL/PW 0.97, 0.99;

PL/PAW 1.16, 1.21;

PBW/PAW 1.20, 1.27;

PL/EL 0.23, 0.25;

EL/EW 2.91, 2.97.

Etymology. – The new name is derived from the type locality, Gunung Bawang (Mt. Bawang) in West Kalimantan (Borneo).

Distribution. – Borneo ( West Kalimantan).

Differential diagnosis. – This new species shares the characteristic serrate expansion of the apical antennomeres with most other species of the same genus from Borneo, but it is one of the larger species in the genus Microdebilissa , and the only one exceeding 5 mm in body length occurring in Borneo ( Pascoe, 1869; Holzschuh, 2014). It is also distinct in its long tempora, flattened disc of pronotum, relatively long, black elytra with a wide light brown stripe starting near the base, a feature not found in any related species.As mentioned above, the serration of the apical antennomeres is commonly observed in the Bornean species of this genus, though never so prominently. While the almost entirely black colour is shared with M. nigrica Holzschuh, 2014 , that species is much smaller, at about 3 mm in body length, and has just a small spot on each external margin near the middle of the elytra, making it easy to distinguish from this new species ( Holzschuh, 2014).

Notes. – This new species was discovered relatively recently, and so it is only known from the slopes of Mt. Bawang in West Kalimantan, Indonesia.

The rake organ is a structure located on the female abdominal sternites and is involved in oviposition processing behavior. For more details, we refer to Niisato (2012).