Some new records of scarab beetles of the genus Onthophagus Latreille, 1802 (Coleoptera: Scarabaeidae) from northern Western Ghats, Maharashtra, with a checklist

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Latreille in 1802 established the genus Onthophagus.
It belongs to the tribe Onthophagini of the subfamily Scarabaeinae, and family Scarabaeidae. It is comprised of nearly 2,200 described species (Schoolmeesters 2016) from the world, making it a very diverse genus in the subfamily representing almost 38% of the Scarabaeinae beetles (Rossini et al. 2018) with cosmopolitan distribution (Tarasov & Kabakov 2010). Approximately, 182 species have been reported from Indian mainland (Arrow 1931;Balthasar 1963;Löbl & Smetana 2006;Sathiandran & Sabu 2012). From Maharashtra, nearly 25 species are reported by Arrow (1931) and Jadhav & Sharma (2012).
Beetles from Scarabaeinae are being considered as important biological indicators due to their higher sensitivity to the changing climatic conditions (Rossini et al. 2018). Beetles of the genus Onthophagus are coprophagous and some are scavengers (carrion feeders). The main food source of these beetles is the faeces of animals, which they partially decompose (Fischer 2006), and helps in increasing the nutrient content, texture and structure of soil. They are paracoprid nesters (tunnelers) with biparental care, an important phenomenon of the genus Onthophagus, wherein the female digs branched tunnel with a brood chamber under the dung pat and males move the portion of dung to the entrance of these tunnels and then, female makes pieces, put it in the brood chamber and lay one egg in each chamber (Sowig 1996).
The Western Ghats is one of the important biodiversity hotspots of the world (Myers 2003), with high level of endemism and species richness. The northern Western Ghats ecoregion is dominated with drier dipterocarp (Sabu et al. 2011), harbouring a vast diverse fauna along with endemic species. The Oriental Onthophagus fauna is inadequately studied (Tarasov & Kabakov 2010). Also, Tarasov & Kabakov (2010) and Sathiandran & Sabu (2012) stated that the taxonomic J TT errors from the Indian subcontinent are high for this genus. Moreover, the major documents like Arrow (1931) and Balthasar (1963) reporting this genus from this region are outdated (Sathiandran & Sabu 2012). Therefore, documenting diversity of this highly diverse genus will play an important role in removing the confusions and errors.
The dung beetle fauna of southern Western Ghats is very well documented (Arrow 1931;Balthasar 1963Balthasar , 1974Vinod & Sabu 2007, Sabu et al. 2011Sathiandran & Sabu 2012;Sathiandran et al. 2015;Latha and Sabu, 2018). Sabu et al. (2011) recorded about 78 species of Onthophagus from moist southern Western Ghats. Of these recorded species, 19 are endemic to the entire Western Ghats, 12 are regional endemics to southern Western Ghats and a single species is a local endemic to the tropical montane cloud forest. On the contrary, very few or scattered publications are available on the diversity of dung beetle fauna from northern Western Ghats, Maharashtra (Arrow 1931;Balthasar 1963Balthasar , 1974Jadhav & Sharma 2012;Kalawate 2018). Hence, in the present study, an attempt has been made to prepare an updated checklist of the genus Onthophagus based on the collections from recent surveys, unidentified collections present at ZSI, WRC, Pune and also from the literature (Arrow 1931;Balthasar 1963Balthasar , 1974Jadhav & Sharma 2012;Kalawate 2018).
Specimens were collected from different parts of the northern Western Ghats, Maharashtra. They were collected by installing light traps using 160-Watt mercury bulb as a light source as they are attracted to the light in night. Some of the beetles were hand-picked from the dung pats present in the field in day during the field surveys in the northern Western Ghats, Maharashtra. The collected beetles were euthanized by ethyl acetate vapours and brought to the laboratory for further studies. The specimens were relaxed, pinned and stored in the fumigated entomological boxes for further examination. They were examined under Leica EZ4E® with in-built photographic facility. The male genitalia were dissected wherever necessary by carefully removing it from the abdomen. After removal, it was further boiled in 10% KOH for 5-10 minutes to remove the adhered tissues and soft muscles and then rinsed in distilled water. The genitalia were stored in separate vials containing 70% ethanol with same catalogue number as the specimen. The map of the collection locality has been prepared using QGIS software. The beetles were determined as per the available literature viz., Arrow (1931) and Balthasar (1963) and the classification followed is as per Arrow (1931) and Balthasar (1963) with modifications as per Lobl & Smetana (2006). The distribution of the species provided here are taken from Arrow (1931), Balthasar (1963), Chandra & Gupta (2011, 2013, Sabu et al. (2011), andSathiandran et al. (2015). The checklist of the genus Onthophagus from Maharashtra including northern Western Ghats (Maharashtra) based on the collections from the recent surveys, unidentified collections from ZSI, WRC, Pune and also from the literature, with the record of endemic beetles has been provided.
A total of 36 species in eight subgenera of Onthophagus have been reported based on the recent collection (*) and reports from available literature.

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Onthophagus (Onthophagus) madoqua. Balthasar, 1963; Monographie der Scarabaeidae und Aphodiidae der Palaearktischen and Orientalischen Region Description (Image 1A): Length, 4-5 mm., breadth, 3mm. Black, shining, oval and convex. Head coppery, short and broad; clypeus smooth in front, with its margin strongly reflexed; forehead separated by curved carina; a pair of quite separate, straight, erect and parallel horns at vertex. Pronotum deep golden-green, smooth in front, slopes steeply but not abruptly. Elytra decorated, red patch on each elytron at shoulder and hind margin. Upper surface clothed with erect pale setae.
Male genitalia (Image 1B): Phallobase is almost same in length as parameres, gently curved in lateral view. Parameres funnel shaped, broad at base, minutely constricted in the middle, strongly bent downward, acuminating, tips rounded. Maximum Length, about 1.39mm; maximum width, about 0.504mm.
O. zebra Arrow, 1931 Kalawate Description (Image 1 C): Length, 7mm., width, 4mm. Dark brown, smooth and shining, oval and convex. Clypeus feebly produced, front margin rounded and strongly reflexed, separated from forehead by a short transverse carina. Near inner margin of each eye, a short, erect, blunt, conical horn present. Pronotum with three small tubercle, one just behind the front margin in the middle and a pair positioned between the front and hind margins, the space between these tubercles slightly depressed but not smooth. Elytra testaceousyellow, with brown-black bands at the inner and outer margins, which usually more or less fused together in the middle line. The pygidium and the femora are yellow, with minute setae. Male genitalia (Image 1 D): Phallobase larger than the parameres, broader and tubular. Parameres roughly triangular, broad at the base, acuminating towards the tip, rounded tip, curved ventrally. Maximum length, about 2.01 mm; maximum width, about 0.967mm.