On the discovery of a new polymorphic Happy-Face Spider (Araneae, Theridiidae) from the Western Himalayas, India, with notes on its natural history

A new species of Theridion is reported here from Uttarakhand, India which resembles and exhibits polymorphism like the Happy-face spiders reported from the Hawaiian Islands, Theridion grallator. The species is polymorphic in both sexes and exhibits patterns of a smiling face with dots in colours of red, black and white arranged differently. 32 different morphs of the species have been reported here which have been collected from three different locations in the northwestern state of India, Uttarakhand.

This Theridion species also builds webs to hang upside down like the other polymorphic spiders T. californicum and T. grallator. The phylogenetic position of the species is also reported here which was compared against some of the Asian and Neotropical species across the world using the COI marker. A genetic variation of around 8.5 % is observed from the Hawaiian Happy-face spider which indicates a separately evolved species in Asia where several morphs have been found.

Despite moderate overall divergence, T. himalayana appears to be phylogenetically isolated from both its Palearctic and Nearctic congeners. This supports its distinctiveness within the genus and raises broader questions about lineage dispersal, parallel evolution of colour polymorphism and independent evolution of species in montane forests. A dichotomous key to the Theridion species described form India is also presented here.