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) Author Lopardo, Lara Author Hormiga, Gustavo text Zoological Journal of the Linnean Society 2015 2015-02-16 173 3 527 786 http://dx.doi.org/10.1111/zoj.12199 journal article 123829 10.1111/zoj.12199 02f79ff2-493a-449e-8206-5662abfa5c52 0024-4082 5331625 MYSMENOPSIS SIMON 1897 ( FIGS 53–62 , 128G , 131A–C , 140G–L : CLADE C190) Lucarachne Bryant, 1940: 350 ( type L. tibialis Bryant, 1940 ). Kraus, 1955: 30 . Forster, 1959: 328 . Gertsch, 1960a: 28–29 . Platnick & Shadab, 1978: 5 (synonymized to Mysmenopsis ). Chickering, 1960: 95 (misidentification). Wunderlich, 1978: 29 . Mysmenopsis Simon, 1897: 865 . Gertsch, 1960a: 23 . Platnick & Shadab, 1978: 5–20 (revision of the genus) . Müller, 1987: 185 . Coyle & Meigs, 1989: 61–66 . Baert, 1990: 5–17 . Platnick, in Eberhard, Platnick & Schuh, 1993: 8 . Jocqué & Dippenaar-Schoeman, 2006: 176 . Type species Mysmenopsis femoralis Simon 1897 by original designation, syntype material in BMNH and MNHN, examined. Familial placement and composition Transferred to Symphytognathidae from Theridiidae by Gertsch (1960a), and to Mysmenidae from Symphytognathidae by Forster & Platnick (1977). Our working phylogenetic hypothesis places Mysmenopsis as sister to Isela within the subfamily Mysmenopsinae ( Fig. 161B ). Currently, the genus Mysmenopsis comprises 27 described species (Platnick, 2014), and is here represented by four species: M. dipluramigo , M. penai , M. cidrelicola , and M. palpalis . Monophyly Morphological synapomorphies of Mysmenopsis include: anterior atria connected by membranous duct ( Fig. 60H ); posterior lateral tracheae branching into several tracheoles ( Fig. 60G ); wide posterior spiracular opening ( Fig. 59I ); distal labium concave ( Figs 54B , 56G , 59E ); relatively higher proportion of maxillary clavate setae ( Fig. 62B ); and four or more colular setae ( Fig. 56D ; three or less setae in M. palpalis , Fig. 59I ); males with prolateral row of modified setae occupying only distal half of tarsus I ( Figs 54G , 59D ); with prolateral cymbium ( Fig. 59A, G ) without internal cymbial conductor and cymbial fold (CyC1 and CyF; Figs 53D , 55G , 60C, D, F ); short apical bifid embolus of lobed or weakly projected embolic base and with membranous (flexible) embolus–tegulum junction ( Figs 55G , 58D , 60D, F , 131A, C ); globose palpal tibia ( Figs 53A–C , 55A–E , 58A–B , 59A , 60A , 131A ) with apical hollow area ( Figs 53E , 55H , 58A, B , 60B , 131A–C ); and females with a distal ventral femoral I projection ( Figs 57A, B, E , 140G ). Other Mysmenopsis species have either a femoral spot or no structure at all (Platnick & Shadab, 1978), although it is unclear whether the presence of the spot is plesiomorphic for the family or whether it represents a secondary gain. Ambiguously optimized synapomorphies for this clade include the following characters: cheliceral retromargin without teeth; absence of median structures of posterior respiratory system ( Fig. 60G ); male metatarsus I with proximal row of between five and eight spines ( Fig. 57G, H ; absent in M. penai ); epiandrous fusules in two discrete clusters ( Fig. 56E ); males with flagelliform gland spigots ( Figs 53H ; 58G ); cymbial tip without conductor grooves, but with a distinctly shaped tip ( Fig. 58D ) and with a hook-shaped paracymbium bent inwards and associated with a tegular groove ( Figs 53D, F , 55F , 58D , 60D ); male palpal tibial bearing spurs ( Figs 53E , 55I , 58E , 60B, E ) and with two retrolateral–dorsal trichobothria ( Fig. 55E ). Diagnosis Mysmenopsis differs from all other mysmenid genera in the following combination of features: the respiratory system consisting of anterior tracheae connected by a membranous duct and posterior lateral tracheae branching into several tracheoles, without median structures, arising from a wide posterior spiracular opening; the typical male palpal conformation, including a globose tibia with an apical hollow area bearing spurs and with two retrolateral–dorsal trichobothria, a prolateral cymbium without internal conductor grooves or cymbial fold, but with a distinct tip, and with a hook-shaped paracymbium bent inwards and associated with a tegular groove, and a short apical bifid embolus. Also, a distal ventral projection on femur I occurs on females, males have a prolateral row of modified setae occupying the distal half of tarsus I, and a proximal row of between five and eight spines on metatarsus I (absent in M. penai ); the epiandrous fusules are grouped into two clusters, both sexes retain only the flagelliform but not the aggregate spigots on the posterior lateral spinnerets; the labium is distally concave, a relatively higher proportion of maxillary clavate setae occurs in the mouthparts, and the colulus has four or more setae (three or less setae in M. palpalis ). The taxonomic history and previous diagnostic features for Mysmenopsis have been reviewed by Platnick & Shadab (1978). Some of the previous diagnostic features proposed for this genus are also recovered here (see Simon, 1897; Bryant, 1940; Gertsch, 1960a; Platnick & Shadab, 1978).