First report of the termite Glyptotermes ceylonicus (Blattodea: Isoptera: Kalotermitidae) from India: an example of discontinuous distribution

: We report Glyptotermes ceylonicus (Holmgren, 1911), an endemic Sri Lankan termite, for the first time from India. Glyptotermes show a high degree of endemism throughout the world. Record of this species from the current location indicates a wide distribution of this species in southern India, in the past, before the complete separation of Sri Lanka from India. The current distribution of Glyptotermes ceylonicus is also an example of discontinuous distribution. Pictorial illustrations of the morphologically important parts and revised key for the Indian species are provided.

ISSN 0974-7907 (Online); ISSN 0974-7893 (Print) Glyptotermes ceylonicus is a species of damp wood termite endemic to the high elevations of Sri Lanka. Holmgren (1911) described G. ceylonicus from Peradeniya, Ceylon. Glyptotermes is a highly endemic genus of the family Kalotermitidae. Krishna et al. (2013), reported 456 species from this family, including 127 species of Glyptotermes. Two more species were introduced into the genus recently, making a total of 129 Glyptotermes species worldwide. In India, eight of the 13 species of Glyptotermes species reported are endemic (Thakur et al. 2010;Amina & Rajmohana 2016;Sengupta et al. 2019). Three species of Glyptotermes-ceylonicus Holmgren (1911), dilatatus (Bugnion & Popoff 1910), and minutes Kemner 1932-reported from Sri Lanka are endemic to the area (Sri Lanka). None of the Indian species of Glyptotermes were reported from Sri Lanka. Likewise, none of the Sri Lankan species of Glyptotermes were reported from India. The total termite species reported from Kerala is 67, which belongs to three families and 30 genera (Mathew & Ipe 2018).

Materials and Methods
Termites were collected from Pinnakkanadu, Kottayam district of Kerala State, located in southern India. The study area is situated between 9.64°N and 76.76°E at an altitude of 97.536 m. The collection was made from the core of a rotten wood of Hevea brasiliensis Müll.Arg, 1857, with high moisture content. The periphery of the wood was severely infected with Heterotermes indicola (Wasmann, 1902). The specimens were collected using an aspirator and preserved in 80% alcohol. Voucher specimens were deposited in the Zoological Survey of India (ZSI) Western Ghats Regional Centre Specimen Repository with register number ZSI/WGRC/I.R.-INV.17975. Measurements were J TT made in 80% alcohol under a stereo zoom microscope, Labomed Luxeo 4D binocular microscope with attached camera and pixel pro software at magnification of 8-35X. Morphological terminology, measurements and indices for describing soldiers, workers and imago follow Roonwal & Chhotani (1989) and Sands (1998). Mandibles, antennae, and labrum of the imago, soldier and worker caste were mounted on a glass slide for examining diagnostic characters. Photographs were taken using Labomed Luxeo 4D binocular microscope with an attached camera.

Diagnosis
Soldier: (Image 1, Table 1). Head-capsule brownish yellow, frons reddish-brown with an inclination angle of about 70°. Labrum and antennae pale yellow. Mandibles black, body and legs straw yellow. Head sparsely and body moderately hairy. Mandibles with short hairs at basal humps. Head-capsule sub-rectangular, length a little less than twice width. Antennae with 12 segments, segment three shortest. Mandibles thick, stout, and short, broadly narrowed at tips. Left mandible with two large and broad marginal teeth. First marginal situated at about one-fourth from the distal tip or closer to tip, second marginal broader and situated medially or just below first postmentum long, club-shaped, widest anteriorly at one fourth, waist long and narrow, minimum width of waist less than half to about half of maximum width.
Imago: (Image 2, Table 2). Head brown, paler in front. Pronotum paler than head. Abdomen brownish above paler below. Wings iridescent, with brownish anterior veins. Head thick, almost quadrately oval. Eyes and ocelli are small, ocelli separated from the eyes by their diameter or a little more. Clypeus short. Antenna 13 segmented, distinctly thickened distally. Segment two is almost as long as three.
Pseudoworker: (Image 3, Table 3). Head-capsule pale yellow, antennae, labrum, legs and body paler. Head and body moderately hairy. Head-capsule subcircular, a little broader than its length to base of mandibles. Eyes translucent and round. Ocelli absent. Antennae with 13 segments, segment three shortest. Labrum broadly tongue-shaped, hairy near anterior margin and on body. Mandibles typically Glyptotermes-type.

Biology
Glyptotermes ceylonicus is a rare species in Sri Lanka and India. It is reported from dead, decaying logs and branches of Hevea, Acacia, and Artocarpus integrifolia Linn.f. 1782. In Sri Lanka, it is found at an altitude between 460-610 m. In India, it is reported at 97.536 m. The nest is in the form of longitudinal galleries. The galleries and chambers contain a small round heap of faecal matter.

Discussion
Kalotermitidae is a monophyletic lineage (Inward et al. 2007); it contains lower termites that evolved during the Cretaceous period. Three species of Kalotermitidae are preserved in Miocene amber from the Dominican Republic, which belong to the living genera Cryptotermes, Glyptotermes, and Incisitermes (Rohr et al. 1986). The higher distribution and abundance of Glyptotermes in the Neotropical (34.2%) and Indo-Malayan (31.5%) regions suggest, the genus had its origin in either of these regions. They got dispersed in the late Jurassic or early Cretaceous to the Australian and Papuan regions and dispersed through the Bering land bridge (Emerson 1952(Emerson , 1955 or they originated in southern landmass when they were contiguous and dispersed before landmass drifted apart according to Warner's hypothesis (Chhotani 1970). Either of the two theories gives an insight into the reason behind the peculiar distribution.
Studies show that East Gondwana, including India, split from West Gondwana between 165 and 150 million years ago (Krutzsch 1989;McLoughlin 2001;Briggs 2003). The collision of the Deccan plate (comprising India, Sri Lanka, and Seychelles) with Laurasia during the Eocene between 55 and 40 million years ago led to the rise of the Himalayan chain (Partridge 1997;Willis & McElwain 2002). The tropical climate of this region supports the development of the tropical biome in southeastern Asia. Sri Lanka was probably connected to India until 6,000 years ago, with a continuous stretch of tropical rain forest, which permitted the exchange of fauna of these regions. Later, Sri Lanka separated from the Indian mainland due to rise in sea levels (McLoughlin 2001).
Roonwal & Chottani ( Currently, a total of 17 Glyptotermes species are reported from the Indian region. Earlier it was thought that Glyptotermes ceylonicus was restricted to Sri Lanka. This is not a very common species and was earlier reported from Chilaw, Hewaheta, Elpitiya, Kurunegala, Pasara, and Peradeniya at an elevation of 460-610 m (Hemachandra et al. 2012). This species prefers to feed on dead, decaying logs and branches of Hevea, Acacia, and Artocarpus integrifolia with high water content (Roonwal & Chhotani 1989). Through the present study, we report Glyptotermes ceylonicus for the first time in India. The population is found in the western part of Western Ghats, 500 km (aerial distance) away from the currently known location, at an elevation of 97.536 m. The species may have been widely distributed in southern India before the separation of Sri Lanka from India. Invasion through traded goods is thin because artificial transport of this rare species is difficult (Chhotani 1970). These family of termites are obscure in nature, except Paraneotermes simplicicornis, which exclusively dwells in woody structures (Thakur et al. 2010), resulting in under-exploration. Another reason for the absence of this species from the area between Sri Lanka and current location might be due to the extinction in the intermediate areas due to the influence of anthropogenic factors (Basu et al. 1996). Amina et al. (2013) reported Sri Lankan termite Hospitalitermes monoceros (Konig, 1779) from Chinnar Wildlife Sanctuary, Western Ghats, Kerala. This also supports our view that many termites are distributed in southern India and Sri Lanka and later dwindled to narrow geographical areas. The present documentation of Glyptotermes ceylonicus is an example of discontinuous distribution.      The Journal of Threatened Taxa (JoTT) is dedicated to building evidence for conservation globally by publishing peer-reviewed articles online every month at a reasonably rapid rate at www.threatenedtaxa.org. All articles published in JoTT are registered under Creative Commons Attribution 4.0 International License unless otherwise mentioned. JoTT allows allows unrestricted use, reproduction, and distribution of articles in any medium by providing adequate credit to the author(s) and the source of publication.