First record of Proceratium Roger, 1863, Zasphinctus Wheeler, 1918, and Vollenhovia Mayr, 1865 (Hymenoptera: Formicidae) from the Western Ghats of peninsular India, description of three new species, and implications for Indian biogeography

Abstract

Three new ant species from the genera Proceratium Roger, 1863, Zasphinctus Wheeler, 1918, and Vollenhovia Mayr, 1865 are described from the Western Ghats of southern India. This is the first report of Proceratium and Zasphinctus from peninsular India and the first record of Vollenhovia from the Western Ghats mountain range proper. Proceratium gibbosum sp. nov. is described from Periyar Tiger Reserve in Kerala, being the first record of the stictum species group from the Indian subcontinent; it differs from other members of the stictum group by the mesonotum bearing a prominent rounded dorsal hump (tumulus) and petiole devoid of ventral tooth. The first record of the genus Zasphinctus Wheeler, 1918 from the Indian region is also presented here, with a description of a new species. Zasphinctus sahyadriensis sp. nov. differs from all known Afrotropical and Asian Zasphinctus by a combination of characters including clypeal area with single median tooth, occipital margin being regular in outline, and head sculpture sparsely punctate. The occurrence of the genus Vollenhovia Mayr, 1865 is confirmed from peninsular India, with the description of the female castes of Vollenhovia keralensis sp. nov. We provide ecological notes on these new taxa. In addition, separate identification keys based on the worker caste are also presented to Indo-Malayan species of Proceratium, Afrotropical-Indomalayan species of Zasphinctus, and Vollenhovia of the Indian subcontinent. The biogeographical implications of the presence of these three genera are also discussed in relation to plate tectonics of the Indian subcontinent.

Overview of the ant genus Vollenhovia (Hymenoptera, Formicidae) in India and Sri Lanka, with an illustrated key and the description of a new species

“…This species from the Western Ghats closely resembles V. karimalaensis from the same region but can be separated based on the number of mandible teeth, the sculpture, and the petiole shape (see Remarks under V. karimalaensis). It is one of the few species of the genus of which all three castes have been described (Sadasivan & Kripakaran 2022). We were able to collect specimens from two new localities…”

“…The taxonomy of Asian species has been treated in various regional works before this study, focusing on mainland China (Wu & Wang 1995), Japan (Terayama & Kinomura 1997), Taiwan (Terayama 1999(Terayama , 2009, Singapore (Wang et al 2021), and India (Bharti & Kumar 2013;Sadasivan & Kripakaran 2022;Dhadwal et al 2023). However, a revision conducted at a broader geographic scale still appears necessary to assess the taxonomy of certain species, such as those from the oblonga and penetrans complexes mentioned in this study.…”

“…The widespread Vollenhovia emeryi Wheeler, 1906, which successfully colonized parts of Eastern Asia and the United States after being introduced (Wetterer et al 2015), has also been found in urban parks (Iwata et al 2005;Harada et al 2010) and in agricultural fields (Hosoishi et al 2007). Little is still known of the diet of Vollenhovia ants, but species may be mostly predatory, feeding on beetle larvae and a variety of other small arthropods (Sadasivan & Kripakaran 2022). The genus is known to include workerless socially parasitic species and is peculiar for queen polymorphism, clonal reproduction, and caste differentiation mechanisms (Ohkawara et al 2006;Ohkawara & Satoh 2015).…”