Taxonomy and molecular phylogeny of long jawed spiders (araneae: tetragnathidae) in Kerala.

Abstract

The family Tetragnathidae, commonly known as long jawed spiders, is distributed in the tropical and subtropical areas of the world. The present study is the first to systematically investigate the taxonomy and molecular phylogeny of tetragnathids in Kerala with the purpose of delimiting species boundaries and understanding interrelationships between them. The study documented a total of 27 tetragnathids under eight genera from the state of Kerala, which constitutes 48% of the Indian tetragnathid fauna. A new six-eyed Dolichognatha species, D. chimminiensis sp. nov., described during the study represents the third of the genus from India. Tetragnatha cochinensis, T. viridorufa, Tylorida flava, and Atelidea sp. were recorded as endemic to India. This is the first to record T. lauta, T. squamata, T. serra, T. jaculator and a silvery spider, Leucauge rubromaculata from India. Males of L. fastigata and Tylorida flava were recorded for the first time in India and this is the first to describe the latter species with an exhaustive account of its body morphology and genitalic characters. Furthermore, T. chamberlini was proposed as the junior synonym of T. javana and T. andamanensis was synonymized with T. hasselti. Since the taxonomic accounts of many of the tetragnathids were inadequate, T. cohinensis, T. geniculata, and T. serra were rigorously redescribed and the former species was revised after a century. The barcode data generated during the current study were satisfactorily concordant with the traditional morphological characters. The concatenated nucleotide sequences of CO1 and 18S fairly resolved the evolutionary relationship between tetragnathids by employing Neighbour Joining (NJ), Maximum Parsimony (MP), Maximum Likelihood (ML), and Bayesian Inference (BI) approaches. The monophyly of the family Tetragnathidae was evident with the clustering of four subfamilies, such as Tetragnathinae, Leucauginae, Metainae, and Nanometinae.