TETRAGNATHIDAE

Álvarez-Padilla, Fernando, 2007, Systematics of the spider genus Metabus O. P. - Cambridge, 1899 (Araneoidea: Tetragnathidae) with additions to the tetragnathid fauna of Chile and comments on the phylogeny of Tetragnathidae, Zoological Journal of the Linnean Society 151 (2), pp. 285-335 : 288

ARANEOIDEA AND TETRAGNATHIDAE

In this analysis Tetragnathidae is sister to the ‘reduced piriform clade’ (RPC) sensu Griswold et al. (1998). Tetragnathidae plus the RPC are sister to Araneidae and all these taxa conform to Araneoidea. The phylogenetic relationships within the RPC are beyond the scope of this paper and were studied in some detail by Griswold et al. (1998). Two synapomorphies support the monophyly of the RPC: short bases of the piriform spigots (7-1) and the three-dimensional web structure (105-1). Tetragnathidae and the spiders of the RPC share three synapomorphies: the loss of the aciniform anterior brush of the PMS (9-1), the nonsticky silk spiral and the first sticky silk in contact (102-1), and the use of the iL1 (first leg facing the hub) to measure where to attach the sticky silk spiral (103-1). Two synapomorphies support the monophyly of Araneidae : the grooved booklung cover cuticle (3-1), and the presence of a radix in the embolic division (69-1). The booklung cover cuticle is also grooved in Nephilinae , except Clitaetra Simon, 1889 , and in Meta within the ‘metines s.s. ’ clade. The phylogenetic relationships of Araneidae have been studied in detail elsewhere ( Scharff & Coddington, 1997).