Onitis excavatus Arrow, 1931

Karimbumkara, Seena Narayanan & Priyadarsanan, Dharma Rajan, 2024, Study on the genus Onitis (Coleoptera: Scarabaeidae: Scarabaeinae) of the Indian Subcontinent, with three new species from India, European Journal of Taxonomy 956, pp. 1-61 : 20-21

Onitis excavatus Arrow, 1931

Figs 5E , 6A–D , 18

Onitisexcavatus Arrow, 1931: 391 (original description).

Onitis excavatus – Balthasar 1935: 93 (monograph); 1963: 37 (monograph). — Janssens 1937: 50 (revision); 1938: 2 (notes). — Biswas & Chatterjee 1985: 158 (distribution). — Mittal 2005: 46 (list). — Bezdek & Krell 2006: 159 (distribution). — Chandra et al. 2012a: 52 (distribution). — Siddiqui et al. 2014: 300 (distribution). — Gupta et al. 2015: 1037 (checklist). — Bezděk 2016: 179 (distribution). — Schoolmeesters 2022 (online catalogue).

Differential diagnosis

Onitisexcavatus closely resembles O. falcatus , both placed in Group I. These two species are similar as the pronotum is smooth or sparingly punctured, and the former differs from the latter in having larger and broader body, a deep transverse excavation behind the middle of the metasternum and presence of strong sharp teeth at the extremity of mesofemur in male.

Type material examined

Lectotype

MYANMAR • ♂; “ Tenasserim, Atkinson Coll.92–3, near O. Ludekingi, Lansb. , but quite diff. by sculptures, Onitis excavates male Arr., M.E. Bacchus det. 1975”; BMNH (E) 1237173.

Additional material examined (29 specimens)

INDIA • 2 ♂♂, 5 ♀♀; Arunachal Pradesh, Pakke ; 27°14ʹ17.73″ N, 93°32ʹ14.28″ E; elev. 877 m a.s.l.; hand-picked from elephant dung; 24 Sep. 2018; Priyadarsanan Dharma Rajan and team leg.; AIMB / Co/Sc1000037 to 1000044 • ♂, ♀; Arunachal Pradesh, Sibuk ; 28°21ʹ43.7184ʺ N, 95°15ʹ57.1968ʺ E; elev. 956 m a.s.l.; 3 Oct. 2018; hand-picked from cow dung; Harsha Malhotra and team leg.; AIMB / Co/Sc1000045 to 1000046 • ♀; Arunachal Pradesh, community forest, Pasighat, Rani Village ; 27°31ʹ27.138ʺ N, 27°31ʹ27.138ʺ E; elev. 1557 m a.s.l.; 9 Oct. 2018; hand-picked from donkey dung; Harsha Malhotra and team leg.; AIMB / Co/Sc1000047 • ♀; Arunachal Pradesh, Ziro, Talley Valley ; 27°31ʹ23.4984ʺ N, 93°50ʹ22.0308ʺ E; elev. 1532 m a.s.l.; 10 Oct. 2018; hand-picked from cow dung; Harsha Malhotra and team leg.; AIMB / Co/Sc1000048 • ♂; Arunachal Pradesh, Sangri, Mobu ; 27°14ʹ1.5324ʺ N, 93°31ʹ58.8576ʺ E; elev. 805 m a.s.l.; 18 Oct. 2018; hand-picked from mithun dung; Harsha Malhotra and team leg.; AIMB / Co/Sc1000049 • ♀; Arunachal Pradesh, Seijosa, Pakke Tiger Reserve ; 26°56ʹ56.2596ʺ N, 92°59ʹ4.3764ʺ E; elev. 164 m a.s.l.; 23 Sep. 2018; hand-picked from elephant dung; Harsha Malhotra and team leg.; AIMB / Co/Sc1000050 • 6 ♂♂, 4 ♀♀; Arunachal Pradesh, Seijosa, Pakke Tiger Reserve ; 26°56ʹ31.128ʺ N, 92°58ʹ17.76ʺ E; elev. 190 m; 24 Sep. 2018; hand-picked from elephant dung; Harsha Malhotra and team leg.; AIMB / Co/Sc1000051 to 1000060 • ♂; Arunachal Pradesh, Pasighat, Rani village ; 27°58ʹ6.0276ʺ N, 95°19ʹ12.5328ʺ E; elev. 135 m a.s.l.; 29 Sep. 2018; hand-picked from cow dung; Harsha Malhotra and team leg.; AIMB / Co/Sc1000061 • ♂, ♀; Arunachal Pradesh, Pasighat, Rani village ; 27°58ʹ12.9324ʺ N, 95°19ʹ20.5284ʺ E; elev. 125 m a.s.l.; 30 Sep. 2018; cow dung; Harsha Malhotra and team leg.; AIMB / Co/Sc1000061 to 1000062 • ♀; Nagaland, Mon District, Singphan Elephant Reserve ; 25 Apr. 2021; hand-picked from cow dung; Seena Narayanan Karimbumkara and team leg.; AIMB / Co/Sc1000063 .

Description

MEASUREMENTS (in mm). TL=19–25; BW= 13.

Male

Black, shining, elytra and pygidium subopaque; clypeus short, elliptical, moderately closely and finely rugulose; frontal carina widely interrupted in the middle, a short transverse clypeal carina anteriorly, a small tubercle behind, vertex irregularly granular; pronotum very smooth with irregular minute punctures anteriorly, longitudinal groove absent; elytra finely striate with 1st, 3rd and 5th intervals elevated, narrower, rest of the intervals flat; pygidium smooth, unpunctured; metasternum with very deep transverse excavation in the middle, metasternal shield thickly hairy anteriorly, smooth, shining behind; protibia elongate with a serrate carina upon anterior half beneath, four short external teeth and a sharp incurved terminal process; mesofemur with a rounded lobe in the middle of hind edge, two sharp teeth near extremity above and one beneath; trochanters of hind legs acutely produced.

AEDEAGUS (in mm) ( Fig. 6A–D ). LP=3.03, Lp=2.93; BP=1.5, BpB=1.14, BpT=0.46. Parameres shorter than phallobase, straight above and slightly curved outwards below and hooked slightly at the tip.

Female

Legs simple, frontal carina slightly diagonal; punctation of the pronotum heavier and denser, elytral striae deeper than in male; metasternum without transverse pit.

Distribution

India: Arunachal Pradesh, Assam, Himachal Pradesh, Meghalaya, Nagaland, Uttarakhand, Uttar Pradesh. Other countries: China; Myanmar; Nepal; Pakistan; Taiwan; Thailand; Vietnam ( Biswas & Chatterjee 1985; Mittal 2005; Bezděk & Krell 2006; Chandra et al. 2012a; Siddiqui et al. 2014; Ali et al. 2015; Gupta et al. 2015; Bezděk 2016; Schoolmeesters 2022).

Figures

Fig. 5. A. Onitis bordati Cambefort, 1988, holotype, ♂, MNHN EC1187, (image: Antoine Mantilleri, MNHN). B. O. brahma Lansberge, 1875, ♂, BMNH (E) 1237157, (image: BMNH). C. O.castaneus Redtenbacher, 1848, syntype, (image: Harald Schillhammer, NHMW). D. O. crassus Sharp, 1875, holotype, ♂, MNHN EC4813, (image: Antoine Mantilleri, MNHN). E. O. excavatus Arrow, 1931, lectotype, ♂, BMNH (E) 1237173, (image: BMNH). F. O. falcatus (Wulfen, 1786), ♂, AIMB/Co/ Sc1000070, (image: AIMB).

Fig. 6. Aedeagus, lateral, dorsal, ventral and apical views. A–D. Onitisexcavatus Arrow, 1931, AIMB/Co/Sc1000037. E–H. O. falcatus (Wulfen, 1786), AIMB/Co/Sc1000070. I–L. O. bhomorensis sp. nov., NIM/NBAIR/COL/ONIT/H-271023A. M–P. O. punctatostriatus Janssens, 1937, AIMB/ Co/Sc1000492. (Images: AIMB).

Fig. 18. Map showing the distribution of Onitis crassus Sharp, 1875; O. excavatus Arrow, 1931; O. falcatus(Wulfen, 1789); O. feae Felsche, 1907; O. humerosus (Pallas, 1771) and O. kethai sp. nov. in the Indian Subcontinent.