Out of the twilight zone: phylogeny and evolutionary morphology of the orb‐weaving spider family M ysmenidae, with a focus on spinneret spigot morphology in symphytognathoids ( A raneae, A raneoidea)

This paper provides the first comprehensive comparative morphological study of symphytognathoid spiders, with an emphasis on the family M ysmenidae. 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 M ysmenidae. 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 T heridiosomatidae. 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 M ysmenidae are proposed: C rassignatha , Iardinis (to S ymphytognathidae); L eviola (to Z odariidae); and P hricotelus ( A raneoidea incertae sedis ). Mysmenidae is redelimited to include at least eight genera: M ysmena , M icrodipoena , M aymena , T rogloneta , I sela , M ysmenopsis , B rasilionata , and M ysmeniola , which are re‐diagnosed. M ysmenella and A njouanella are synonymized with M icrodipoena . C alodipoena , I tapua , C alomyspoena , T amasesia , and K ekenboschiella are synonymized with M ysmena . Two mysmenid subfamilies are here proposed: M ysmenopsinae subf. nov. and M ysmeninae. 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 A napidae (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. © 2015 The Linnean Society of London