Two new species of Onthophagus (Coleoptera: Scarabaeidae) from Indochina, with a discussion of some problems with the classification of Serrophorus and similar subgenera Author Tarasov, Sergey I. Author Kabakov, Oleg N. text Zootaxa 2010 2344 17 28 journal article 10.5281/zenodo.193356 25d23af4-b9c8-47be-b68e-33ae68076464 1175-5326 193356 Onthophagus (Sinonthophagus) nampatensis Tarasov & Kabakov sp.n. ( Figs. 1 c, d; 3a–d) Material examined. Holotype ( ZMUC ), male bearing the following labels: 1. White, printed: LAOS , Khammouane prov. 10km W of Ban Khun Kham (Nahin) N18°8.922' E104°28.629' , h 280m , limestone tropical forest, dung trap (human). 4– 18.06.2008 leg. S. Tarasov 2. Orange, printed: HOLOTYPUS Onthophagus (Sinonthophagus) nampatensis S. Tarasov & O. Kabakov det. 2009 Paratypes : 1 3, Laos , Khammouane province 10km W of Ban Khun Kham (Nahin) N18°8.922' E104°28.629' , h 280m , limestone tropical forest, dung trap 4– 18.06.2008 leg. S. Tarasov; 1 3, North Thailand , Doi Suthep, 19.6.1958 , h 1100m , leg. B. Degerbøl ( ZMUC ). Description. Body black, slightly lustrous, elytra with stronger luster; antennae and mouthparts orange; elytra and abdomen with short black setae turning white depending on light angle; rest of abdominal side and pygidium with long, orange hairs. Length 10.0– 12.8 mm . Male major ( Fig. 1 c). Head rounded; frontoclypeal ridge slightly expressed, in smaller males more distinct; vertex with a pair of long, tapering and inwardly-rounded horns connected by ridge; eyes completely divided by genal appendage; clypeus densely, transversely rugulose. Pronotum with distinct excavations near anterior angles, anterior part protruding forward between cephalic horns; postlateral section strongly sinuate; anterior and lateral edges marginate, basal edge shortly marginate only near median basal depression; anterior angles slightly protruded forward, widely rounded; pronotal disc covered with simple, sparse punctures (separated by 1–2 puncture diameters) becoming denser and rasplike anteriorly; anterior part of propleura with ridge almost reaching propleural lateral margin. Elytra shagreened, sparsely and densely punctured. Protibia with four outer teeth, median part of anterior edge slightly produced into triangle tooth, internal apical angle with small tooth; apical spur short, acuminate; metatibiae strongly triangularly broadened toward apex; mesotibial and metatibial apex with short and long setae. Aedeagus as in Figs. 3 c, d. Lamella copulatrix with additional internal sclerite (AIS) and small additional lateral sclerite (ALS) ( Fig. 3 a); superior part simple ( Fig. 3 b). Female . Unknown. Va r i a t i o n . Males vary allometrically in the degree of expression of such body parts as horns, pronotum and punctation. Small males ( Fig. 1 d) usually have small horns; anterior part of pronotum with two tubercles medially; pronotum flatter, not concave; disc more densely punctured. Holotype ( Fig. 1 c). Major male, Length 12.8 mm . Body black, slightly lustrous, elytra with stronger luster; antennae and mouthparts orange. Head rounded; frontoclypeal ridge weakly expressed (more distinct in smaller males); vertex with a pair of long, tapering and inwardly-rounded horns connected by ridge. Pronotum with distinct excavations near anterior angles, anterior part protruding forward between cephalic horns; disc covered with simple, sparse punctures (separated by 1–2 puncture diameters) becoming denser and rasplike anteriorly. Differential diagnosis. The new species is most similar to Onthophagus (Sinonthophagus) productus Arrow, 1907 but differs by slightly sparser punctation of the pronotum and distinctly different shape of parameres. It can be also separated from all other species of the subgenus Sinonthophagus Kabakov, 2006 by the unique shape of parameres with protruding lateral lobes ( Figs. 3 c, d). Taxonomic notes. This species has been already cited in two papers as nomen novum in litteris ( Kabakov & Napolov 1999 , Kabakov 2006 ) but has not been described. Moreover, the specimen previously indicated as the holotype ( Kabakov 1999 ) is not included in the type series in this paper because its aedeagus was lost. Though we are certain that the specimen previously chosen as the holotype is conspecific with the current type specimens (also it was collected in the same area with the holotype ), we deliberately excluded it from the type series because the new species can be reliably separated from the close O. productus only by the characters of structure of parameres. For practical reasons we use the same species name as the nomen nudum in Kabakov & Napolov (1999) and Kabakov (2006) . Distribution and Ecology. The new species is known only from north Thailand and central Laos ( Fig. 4 ). In Laos , this species was collected by pitfall traps baited with human dung installed in limestone forest.