Out of the twilight zone: phylogeny and evolutionary morphology of the orb-weaving spider family Mysmenidae, with a focus on spinneret spigot morphology in symphytognathoids (Araneae, Araneoidea)

摘要

This paper provides the first comprehensive comparative morphological study of symphytognathoid spiders, with an emphasis on the family Mysmenidae. Hypotheses of primary homology, particularly at the level of male genitalia, are proposed for a total of 65 taxa (42 mysmenids), compiled into a morphological data set of more than 350 characters. Male palpal structures (paracymbium and tegular conductor), considered absent for the family by previous workers, are actually present in Mysmenidae. The pattern of interfamilial relationships based on the morphological data differs from the hypothesis based on the total evidence (morphology plus multigene sequence data) in the placement of Theridiosomatidae. We have based all formal taxonomic and nomenclatural decisions on the results of analysis of the total evidence from a previous study, except in the cases in which only morphological information was available. Based on such phylogenetic results, the following generic transfers from Mysmenidae are proposed: Crassignatha, Iardinis (to Symphytognathidae); Leviola (to Zodariidae); and Phricotelus (Araneoidea incertae sedis). Mysmenidae is redelimited to include at least eight genera: Mysmena, Microdipoena, Maymena, Trogloneta, Isela, Mysmenopsis, Brasilionata, and Mysmeniola, which are re-diagnosed. Mysmenella and Anjouanella are synonymized with Microdipoena. Calodipoena, Itapua, Calomyspoena, Tamasesia, and Kekenboschiella are synonymized with Mysmena. Two mysmenid subfamilies are here proposed: Mysmenopsinae subf.nov. and Mysmeninae. In addition, diagnostic features for all symphytognathoid families are provided. One significant outcome of this comparative review is the entelegyne internal genitalic conformation for the family Anapidae (as opposed to haplogyne): all anapid representatives examined possess fertilization ducts. We provide some comments on the evolution of the morphology of spinneret spigots in symphytognathoids.(c) 2015 The Linnean Society of London