Scientists discover two new beetle species in Arunachal & Sikkim

Guwahati: Researchers at the Zoological Survey of India did not have to go to the field to look for a new species. In fact, they found it when they were examining the specimens.

Two new species of beetles have been discovered in Sikkim and Arunachal Pradesh by the scientists of the Zoological Survey of India, Kolkata. The new species were found after examining specimens dating to 1992 and 2015.

The findings have been published recently in the journal Zootaxa, a peer-reviewed scientific mega journal for animal taxonomists, published by Magnolia Press in  New Zealand. The study was done by Devanshu Gupta, Denis Keith, Debika Bhunia, Priyanka Das, and Kailash Chandra. 

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Devanshu Gupta, a senior scientist who has been working on beetles, told EastMojo: “We were working on the National Zoological Collection of the Zoological Survey of India, Kolkata when we  found beetle specimens of two species, which were unique in their structure and appearance, and after investigations found them as new to science.”

The scientists named these new species as Melolontha arunachalensis and Melolontha lachugensis based on the localities of the species.

Gupta said the new species in this genus have been described after 127 years. They belong to the genus Melolontha, classified under the family Scarabaeidae. 

Adults in this genus are 25–30 mm long and cause severe damage to crops mainly in the Himalayan region in India.

The male specimens of Melolontha arunachalensis were collected from Pange Valley in Arunachal Pradesh in 2015, whereas, the males of Melolontha lachungensis were collected from Lachung Forest of North Sikkim in 1992. The females of both the new species are yet unknown to science. 

The closest relative of these new species is found in Laos and Vietnam, named M. phupanensis, which was described in 2008. 

M. phupanensis along with M. arunachalensis and M. lachungensis have their antennal club strongly curved outwardly, 3.5 times as length of basal segments; outer metatibial spur subequal in length to length of metatarsomeres 1 and 2 combined; apical portion of pygidium not narrowed, more or less rounded; parameres symmetrical, apical process of left paramere not raised. Both the new species are unique in their structure and shape of the parameres.

Dr. Gupta informed that the genus Melolontha includes 63 species, over 50 of which are primarily distributed in the Palearctic region. After these new discoveries, the total number of species in this genus from India is now 12, and the majority of species are distributed in the Himalayan region. 

Adult Melolontha beetles emerge at end of April or early May and can live for about 5-7 weeks. Females lay 60-80 eggs and bury the 10 to 20 cm deep in the earth. The larvae hatch in 4-6 weeks, mainly feeding on plant roots, such as potato roots. 

He said of the 30,000 faunal species found in the Himalayas, one-third are beetle species.

Apart from the new species, the other Indian species are Melolontha aeneicollis Bates, 1891; M. carinata Brenske, 1896; M. cuprescens Blanchard, 1871; M. flabellata Sharp, 1876; M. furcicauda Ancey, 1881; M. guttigera Sharp, 1876; Melolontha indica Hope, 1831; M. nepalensis (Blanchard, 1851) and M. virescens (Brenske, 1896).

The distinguishing morphological characters and male genitalia of Indian Melolontha have been illustrated, the distribution of each species reviewed, and identification keys for the males have been given.

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