Kakizoe darkling beetle (Microblattellus kakizoei) is the second species after Microblattellus lecongmani Ferrer 2006

NEWS - Kakizoe darkling beetle (Microblattellus kakizoei sp. nov) collected from a mushroom-growing termite nest of Macrotermes gilvus (Hagen, 1858) in Cambodia was established as the second species in the enigmatic tenebrionid genus Microblattellus Ferrer 2006.

Microblattellus was established by Ferrer in 2006 as consisting of a single morphologically peculiar species represented by Microblattellus lecongmani Ferrer 2006 from Vietnam. The genus is characterized by a very distinctive pronotum shape, in which the head is completely hidden beneath the anterior margin, and the absence of eyes.

M. kakizoei is easily distinguished from M. lecongmani by its more elongate and less robust body, looser antennal segments, distinct and transverse scutellum, rather than the reduced and absent one in the latter, distinctly formed humeral angles of the elytra, finely arranged and irregular strial punctures on the elytra, and less prominent body surface.

The holotype is taken from the fungus Macrotermes gilvus (Hagen 1858). The morphology of the mouthparts is most likely to be similar to that of M. lecongmani due to the similarity to other character states. Thus, it may be this character state that delimits the genus. The absence of hind wings is confirmed by micro-Ct data of M. kakizoei.

DESCRIPTION

Male. Body length: ca. 2.1 mm. Body subparallel-sided, reddish brown overall.

Head slightly longer than wide; traces of eyes slightly convex laterally; dorsum almost glabrous; venter with coarse and piligerous punctures; antennae long, somewhat loosely articulate and all antennal segments wider than long except for scape; distal three antennal segments distinctly dilated and forming a club; antennal segments III to XI visible in dorsal view; segment I long, large; segment II almost as long as III, slightly wider than long; segments IV to VIII short and transverse; segment IX widest; segment X slightly shorter and narrower than IX; segment XI 2/5 as wide as X; semicircular labrum; mandibles thick, slightly asymmetric, apically pointed; mentum obtrapezoidal, deeply emarginate on anterior margin; labial palpus with segment I minute, as long as wide; segment II widened apically; III large, oval; maxillary palpus with segment I large, spherical; segment II short, triangular in ventral view; segment III large, oval, slightly truncate at apex.

Pronotum elongate, very feebly bisinuate at sides in basal two-thirds, twice almost as long as wide, widest around anterior 2/5; surface moderately, uniformly punctate, the punctures shallower on apical 1/5, each bearing a seta; basal margin almost straight though faintly produced posteriad; scutellum short and transverse, impunctate, with fine microsculpture; prosternal process oblong-oval, rounded at apex.

Elytra elongate, more than twice as long as wide, widest around middle; humeral corners distinctly projected antero-laterally, and their apices rounded; surface moderately convex, finely, irregularly punctate; each puncture bearing a short seta; lateral margins feebly serrated, and each serration with a short seta; hindwing reduced, brachypterous.

Legs short and robust; femora and tibiae sparsely covered with minute setae, posterior margins of meso- and metafemora ancipital for receiving corresponding tibia; tibiae scarcely incurved, dilated apicad.

Male genitalia; basale more than four times as long as apicale, strongly curved ventrad; apicale short and robust.Female. unknown.

Measurements. head length (from base to labral apex), 486.80; head width, 417.05; antennal length, 582.31; pronotal length, 987.59; pronotal width, 570.43; elytral length, 1242.71; elytral width, 573.08; hind tibial length, 316.02; hind tibial width, 81.03. In micrometers.

Original research

Munetoshi Maruyama, Wei-Ren Liang, Heng Sokh & Kiyoshi Ando (2025). The second species of the enigmatic genus Microblattellus Ferrer, 2006 (Coleoptera, Tenebrionidae) from Cambodia: A possibility of termitophily in the genus. Zootaxa 5575 (1): 167–172, DOI:10.11646/zootaxa.5575.1.8

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