Melalgus borneensis (Lesne), 2012

Liu, Lan-Yu & Beaver, Roger A., 2023, The first Asian species of Polycaon Castelnau, and a new montane species of Melalgus Dejean from China (Coleoptera: Bostrichidae: Polycaoninae), Zootaxa 5315 (3), pp. 271-281 : 278-279

Melalgus borneensis (Lesne)

Heterarthron borneense Lesne, 1911: 45 .

Melalgus borneensis (Lesne) : Borowski & Węgrzynowicz, 2007: 52.

Taxonomy. Lesne (1911) described the species from a single female collected on the island of Borneo (East Malaysia, Sabah). The antennae were described as having 10 antennomeres, with antennomeres 3‒7 together shorter than antennomere 8, the first antennomere of the antennal club. The antennomeres of the club were described as large, very much compressed and leaflike. These antennal characters do not occur in combination in any described species of Melalgus from the Oriental region. The remaining characters given by Lesne (1911) were similar to the females of other species of Melalgus .

Under the name, Melalgus borneensis (Lesne) , Borowski & Węgrzynowicz (2012) describe, key and illustrate both sexes of a species from West Malaysia (Perak). The antennae of this species differ considerably from the original description. They have 11 antennomeres, not 10; antennomeres 3‒7 are longer not shorter than the first club antennomere (antennomere 9 in this species); the three antennomeres of the club are typical of Melalgus , not large, nor very much compressed and leaflike. The antenna of the male is illustrated by Borowski & Węgrzynowicz (2012), but the antennae of Melalgus do not differ significantly between male and female. Further, there is no evidence that the number of segments can differ intraspecifically in the genus.

Unfortunately, the holotype of M. borneensis cannot be located in MNHN (A. Taghavian, LYL), and no other specimens are known. However, the species described by Borowski & Węgrzynowicz (2012) is clearly distinct from all described species of Melalgus , including M. borneensis and M. plesiobatillus . We suggest that the authors have described a species which is not M. borneensis , but is previously undescribed. Details of the collection locality and number of specimens that they examined are not given. In the absence of specimens and further information, we do not name the species.

Distribution. East Malaysia (Sabah).

Biology. Unknown.