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| Theridion himalayana Priyadarshini & Tripathy, in Tripathy et Priyadarshini, 2026. |
Abstract
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.
Key Words: Happy-face spider, polymorphism, dichotomous key, Phylogeny, Theridiidae, Uttarakhand, India
Theridion himalayana Priyadarshini & Tripathy, sp. nov.
Diagnosis. Theridion himalayana sp. nov. can be readily distinguished from other Indian congeners by the unique configuration of the copulatory ducts (CD) and fertilisation ducts (FD). In T. himalayana sp. nov., the CD is elongate, strongly curved, and prominently protruding forward, with both ducts running almost parallel before terminating downward. The CD which is longer than the spermathecae exhibits a distinctive sew-hook–like appearance, which is not observed in any other examined species. The fertilisation ducts are short, narrow, and directed upwards, diverging away from each other to form a V-shaped orientation. The FD arises below the spermatheca, with each duct directed opposite to the CD. This configuration clearly separates T. himalayana sp. nov. from T. odisha, which has a S-shaped, coiled CD that terminates in oval loops and FD inclined towards each other; T. bengalensis, where CD is short, slender, and directed away from each other, while FD appears tapering distally and directed away from spermatheca; T. melanostictum, characterized by extremely long, highly coiled CD and downward-directed, sickle-shaped FD; T. zonulatum, which possesses short, uncoiled CD and looped FD directed upwards.
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Etymology. The specific epithet ‘himalayana’ is assigned to species owing to the locality from which it was first found as an ode to the mighty Himalayan Mountain range that holds a wealth of biodiversity.
Suggested common name. Himalayan Happy-Face Spider.
Ashirwad Tripathy and Devi Priyadarshini. 2026. On the Discovery of A New polymorphic Happy-Face Spider (Araneae, Theridiidae) from the Western Himalayas, India, with notes on its natural history. Evolutionary Systematics. 10(1): 63-84. DOI: doi.org/10.3897/evolsyst.10.174338 [24 Apr 2026]
