Agathidium (Macroceble) acutangulum, Švec, 2012

Švec, Zdeněk, 2012, New Leiodinae (Coleoptera: Leiodidae) from India and Papua New Guinea, Acta Entomologica Musei Nationalis Pragae 52 (2), pp. 411-424 : 419-422

publication ID	https://doi.org/ 10.5281/zenodo.5331202
DOI	https://doi.org/10.5281/zenodo.5398907
persistent identifier	https://treatment.plazi.org/id/297B87BC-A275-FFC2-FECF-61A6FCA1AF42
treatment provided by	Diego
scientific name	Agathidium (Macroceble) acutangulum
status	sp. nov.

Treatment

Agathidium (Macroceble) acutangulum View in CoL sp. nov.

( Figs. 14–16 View Figs , 28, 29 View Figs 18–29 )

Type locality. India, Arunachal Pradesh, 11 km SSE of Tenga, Eagles Nest wildlife sanctuary, 27º06′23″N 92º26′02″E, 2510 m a.s.l.

Type material. HOLOTYPE: J ( NMPC): ‘ INDIA: Arunachal Pradesh (15) / 11 km SSE of Tenga, Eagles / Nest WL Sanctuary, 4.v.2008 / 27º06′23″N 92º26′02″E, 2510 m / Fikáček, Podskalská, Šípek lgt. // Primary evergreen mountain / cloud forest with very sparse / understory vegetation / sifting: wet leaf litter’. PARATYPES: 5 JJ, 12 ♀♀ ( NMPC, ZSPC): same data as the holotype; 1 ♀ ( NMPC): ‘ INDIA: Arunachal Pradesh (12) / 1.6 km SEE of Tawang (at petrol station) / 30.iv.2008, 27º35′55″N 91º52′47″E, 2880 m / Fikáček, Podskalská, Šípek lgt. // small remnants of high Juniperus / Rhododendron forest with / sparse understory vegetation / sifting: leaf litter + fallen / Rhododendron petals’.

Description. Body length 2.2– 2.7 mm (holotype: 2.3 mm). Length of body parts (holotype): head 0.5 mm, pronotum 0.9 mm, elytra 0.9 mm, antenna 0.7 mm. Maximum width of body parts (holotype): head 1.2 mm, pronotum 1.5 mm, elytra 1.4 mm.

Body shortly oval ( Fig. 28 View Figs 18–29 ), black-brown with lighter margins of pronotum and elytra, antennae and legs yellow-reddish. Venter light yellow-reddish. Dorsum without microreticulation, punctate, each puncture with very short and fine seta.

Head. Maximum width of head far before posterior margin of eyes. Eyes flat, 6× as long as wide in dorsal view. Clypeus moderately emarginate, clypeal line lacking. Dorsal surface with rare and very fine punctures separated by much more than 10× their diameter. Mandibles without striking characters. Relative length of antennomeres III: II = 1.4.

Pronotum. Widest at basal third. Lateral sides flatly rounded toward anterior angles in dorsal view; with distinct very closely rounded angle in lateral view ( Fig. 29 View Figs 18–29 ). Puncturation sparser and finer than that of head, here and there with several larger punctures.

Elytra. Broadest approximately at anterior quarter of elytral length. Punctures very small, fine and very rare. Sutural stria absent.

Legs. Anterior tarsomeres I and II a little enlarged in male. Tarsi slender in female. Femora of both sexes with flat emagination at posterior margin situated before and behind midlength, hence forming hardly detectable unobtrusive central angle. Tarsal formula 5-5- 4 in male, 4-4- 4 in female.

Mesoventrite. Longitudinal mesoventral carina low and feeble; lateral lines not developed.

Metathoracic wings absent.

Metaventrite. Femoral lines absent. Both sexes with club-shaped ventro-caudally oriented process at posterior margin between coxae.

Genitalia. Aedeagus as in Figs. 14–15 View Figs ; operculum oval with short notch in middle of anterior margin; spermatheca as in Fig.16 View Figs .

Variability. The length ratio of antennomeres III: II varies between 1.4–1.6 in the type specimens; the ratio of length: width of the eyes in dorsal view between 4–6. The coloration of the dorsum varies from uniformly dark brown (with lighter margins of the pronotum and elytra) to a bicoloured dorsum with a light chest-nut pronotum and/or head with dark brown elytra.

Differential diagnosis. The shape of the aedeagus in Agathidium (Macroceble) acutangulum sp. nov. is almost identical to that in A. (Macr.) caelebs Angelini & DeMarzo, 1981 and in A. (Macr.) sherpa Angelini & DeMarzo, 1981 . The new species is also similar to both the above species in the body size, the length ratio of antennomeres III: II (1.4 in A. caelebs and 1.6 in A. sherpa ), absence of microsculpture on the dorsum, the missing sutural stria and clypeal line. The new species differs from both above species by the shape of the pronotum, having the lateral margin almost angulate (in contrast to broadly rounded lateral margins in both species compared). The new species also differs in the shape of the spermatheca, which is almost spherical in it basal part and twisted in its proximal part (in contrast to the is simply horseshoe-shaped spermatheca in A. sherpa ). The spermatheca of A. acutangulum is slightly similar to that of A. caelebs , but both species differ by the tarsal formula in females (4-4- 4 in the new species, 5-4- 4 in A. caelebs ).

Etymology. The name refers to the shape of the lateral margin of the pronotum of the new species.

Bionomics. The specimens were collected by the sifting of wet leaf litter in a primary evergreen mountain cloud forest, with very sparse understory vegetation, and by the sifting of leaf litter and fallen Rhododendron petals in the small remnants of high Juniperus / Rhododendron forest with sparse understory vegetation (M. Fikáček, pers. comm.).