The mandible character of the Lucanidae is vary by considering of developmental difference in male individual specimen. Especially, species of Genus Cyclommatus Parry, 1862 presents strong mandibular allometry. In this research, The species group which related to Cyclommatus montanellus Möllenkamp, 1904 has been evaluated for the first time in this research with inner teeth composition and positioning to establish clear taxonomic key to each species.

The Subspecies of lucanid beetle Cyclommatus metallifer (Boisduval, 1835) from Indonesia are revised here. Six subspecies were known from Indonesia. Among them, Cyclommatus metallifer otanii Mizunuma and Nagai, 1991 was confirmed to be a synonym of Cyclommatus metallifer aenomicans Parry, 1863. Moreover, a new subspecies, Cyclommatus metallifer butonensis ssp. nov., is described from Buton Island of Indonesia. The identification key, distributional data, photos of adult habitus, male genitalia, and figures for each species are provided.

In this research, taxonomic revision conducted on subspecies of Cyclommatus metallifer (Boisduval, 1835) which are endemic to Indonesia, and totally 6 subspecies were recorded. Among them, Cyclommatus metallifer otanii Mizunuma et Nagai synonymized by Cyclommatus metallifer aenomicans Parry. And also Cyclommatus metallifer ssp. nov. is recorded. total 6 subspecies will be confirmed as valid subspecies