Onitis bhomorensis, Karimbumkara & Priyadarsanan, 2024

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 : 9-11

Onitis bhomorensis sp. nov.

urn:lsid:zoobank.org:act:7D70D754-D82E-4BCA-A3C9-D42645B4F708

Figs 2 , 6I–L , 9A , 14A , 15A , 16A , 17

Differential diagnosis

Onitisbhomorensis sp. nov. is assigned to Group I as its body is completely black and the frontal carina is interrupted. It is similar to O. punctatostriatus in having broad elytral striae. It differs from the latter in the nature of pronotal punctures which are stronger in O. bhomorensis than in O. punctatostriatus ; basal foveae are more spaced in the former than the latter; metasternal shield slightly convex, granular anteriorly with reddish hairs in O. bhomorensis while in O. punctatostriatus it is flat in the middle, with a weak longitudinal groove and with smooth scattered punctures. Clypeal margin truncated, straight in the middle in the former, while it is slightly reflexed in the latter. The presence of a median groove on the pygidium and the rudimentary spur on the protibia make it different from all other Oriental Onitis species. Onitisbhomorensis, is compared with O. assamensis , a species described from a nearby locality as that of the former by Biswas (1980) based on a single specimen. O. bhomorensis is smaller and the body is reddish black, while O. assamensis is greenish. The frontal carina is entire with a tubercle in the former while the carina is interrupted in the latter. The protibia of O. bhomorensis is with a rudimentary spur and the pygidium is with a vertical groove, both these characters are absent in O. assamensis .

Etymology

Named after the bridge “Kolia Bhomora” across Brahmaputra – the widest river in India, near which the type specimen was collected.

Material examined

Holotype

INDIA • ♀; Assam, Tezpur, Kolia bhomora; 10 Oct. 2012; 26°34ʹ56.66ʺ N, 92°51ʹ52.65ʺ E; elev. 74 m a.s.l.; Karimbumkara Seena Narayanan leg.; hand-picked, cattle dung; NBAIR, Bangalore; NIM/ NBAIR/COL/ONIT/H-271023A .

Description

MEASUREMENTS (in mm). TL=18; BW= 10; PL=7; PW=11; EL=10; HL=5; HW=5.1.

Male (holotype)

Body narrow, elongate oval, reddish black, not very shining, slightly convex. Antennae red with the club reddish yellow, legs reddish black; body devoid of setae on the dorsal side, ventral side covered with reddish hairs except on the middle of metasternum and the abdominal sclerites. Head shining with the clypeus truncate ( Fig. 9A ), almost straight anteriorly and at the sides, strongly rugose; clypeal carina present, slightly elevated and curved. The frontal carina is broadly interrupted in the middle with a blunt conical tubercle behind. The vertex punctuation granular, closer in the middle and scattered at the sides appears rugose behind the tubercle. Genae smooth, curved, extended slightly outwards and upwards anteriorly; inner margin slightly elevated and continues behind as a posterior carina. Pronotum moderately convex, sides smoothly margined, except the base which is slightly angulate in the middle; with strong close punctures, closer between the basal foveae; uneven in the middle; deeper and closer anteriorly. Pronotal front angles not very sharp, almost right-angled, the sides straight anteriorly, rounded in the middle, bisinuate behind; hind angles obsolete. A pair of deep basal foveae present at the base on either side of the middle separated by twice its length. Lateral foveae smooth with small punctures in the periphery. Elytra finely and broadly striate, striae devoid of punctures; intervals flat, opaque; sutural interval convex, shining with visible fine scattered punctures. The lateral carinae straight, with minute visible punctures. Pygidium ( Fig. 2F ) without hair or setae, slightly shining with imperceptible scattered punctures. A smooth median longitudinal groove extending from base to almost the middle is present. Metasternal shield shining, ( Fig. 2E ) with minute punctures in the middle; anterior part of the metasternal shield slightly convex, with uneven granules and reddish hairs. Sides of the metasternum closely and evenly granular, covered with smooth short reddish hairs. Protibia slender, bears four external teeth, the tip not very long or curved, with a rudimentary spur near the tip ( Figs 2D , 16A ); teeth short, triangular, placed almost equidistantly. The inner margins of femur and tibia fringed. Femur without protrusion on any of the legs.

AEDEAGUS (in mm) ( Fig. 6I–L ). LP=3, Lp=2.5; BP=1.4, BpB =0.7, BpT=0.4. Parameres almost same length as phallobase, broader at the base and further tapers become slender and slightly curved at the tip. Phallobase slightly broader at the base.

Female

Unknown.

Habitat

The specimen was collected from cattle dung on the river bed of the Brahmaputra, where the vegetation is dry seasonal grasslands, typical of Brahmaputra flood plains dominated by Ziziphusjujuba trees.

Figures

Fig 16. A. Protibia of Onitis bhomorensis sp. nov. showing the position of spur, NIM/NBAIR/COL/ONIT/ H-271023A. B. Anterior tip of protibia of O. punctatostriatus Janssens, 1937, AIMB/Co/Sc1000492. C. Mid-leg of O. kethai sp. nov, NIM/NBAIR/COL/ONIT/H-271023B. D. Mid-leg of O. philemon Fabricius, 1801, AIMB/Co/Sc1000317. E. Mid-leg of O. visthara sp. nov, NIM/NBAIR/COL/ONIT/H- 271023C. F. Mid-leg of O. singhalensis Lansberge, AIMB/Co/Sc1000684. (Images: AIMB).

Fig. 2. Onitisbhomorensis sp. nov., holotype, ♂, NIM/NBAIR/COL/ONIT/H-271023A. A. Habitus, dorsal view. B. Habitus, ventral view. C. Head and prontum. D. Protibia, arrow showing rudimentary spur. E. Metasternum. F. Pygidium, arrow showing longitudinal groove. (Images: 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. 9. Head of male specimens. A. Onitisbhomorensis sp. nov., holotype, NIM/NBAIR/COL/ONIT/H- 271023A. B. O. punctatostriatus Janssens, 1937, AIMB/Co/Sc1000492. C. O. kethai sp. nov., holotype, NIM/NBAIR/COL/ONIT/H-271023B. D. O. philemon Fabricius, 1801, AIMB/Co/Sc1000317. E. O. visthara sp. nov., holotype, NIM/NBAIR/COL/ONIT/H-271023C. F. O. singhalensis Lansberge, 1875, AIMB/Co/Sc1000684. (Images: AIMB).

Fig. 14. Pronotum of male specimens. A. Onitis bhomorensis sp. nov., holotype, NIM/NBAIR/ COL/ONIT/H-271023A. B. O. punctatostriatus Janssens, 1937, AIMB/Co/Sc1000492. C. O. kethai sp. nov., holotype, NIM/NBAIR/COL/ONIT/H-271023B. D. O. philemon Fabricius, 1801, AIMB/Co/ Sc1000317. E. O.visthara sp. nov., holotype, NIM/NBAIR/COL/ONIT/H-271023C. F. O. singhalensis Lansberge, 1875, AIMB/Co/Sc1000684. (Images: AIMB).

Fig. 15. Pronotal basal foveae of male specimens. A. Onitisbhomorensis sp. nov., holotype, NIM/ NBAIR/COL/ONIT/H-271023A. B. O. punctatostriatus Janssens, 1937, AIMB/Co/Sc1000492. C. O. kethai sp. nov., holotype, NIM/NBAIR/COL/ONIT/H-271023B. D. O. philemon Fabricius, 1801, AIMB/Co/Sc1000317. E. O. visthara sp. nov., holotype, NIM/NBAIR/COL/ONIT/H-271023C. F. O. singhalensis Lansberge, 1875, AIMB/Co/Sc1000684. (Images: AIMB).

Fig. 17. Map showing the distribution of OnitisassamensisBiswas, 1980; O. bhomorensis sp. nov.; O. bordatiCambefort, 1988; O. brahma Lansberge, 1875 and O. castaneus Redtenbacher, 1848 in the Indian Subcontinent.