Review of Trichodamon Mello-Leitão 1935 and phylogenetic placement of the genus in Phrynichidae (Arachnida, Amblypygi)

tAmblypygi Thorell, 1883 has five families, of which Phrynichidae is one of the most diverse and with awide geographic distribution. The genera of this family inhabit mostly Africa, India and Southeast Asia,with one genus known from the Neotropics, Trichodamon Mello-Leitao, 1935. Trichodamon has two validspecies, T. princeps Mello-Leitao, 1935 and T. froesi Mello-Leitao, 1940 which are found in Brazil, in thestates of Bahia, Goias, Minas Gerais and Rio Grande do Norte. The boundaries of the species are notwell established and the characters classically used in the group are poorly defined. The relationship ofTrichodamon to the other genera in the family is also subject to debate. Some phylogenetic hypothesespropose Trichodamon as sister to Eurphynichus Weygoldt, 1995 and Phrynichus Karsch, 1879, in the sub-family Phrynichinae. Others suggest Trichodamon in Damoninae, sister to Damon and PhrynichodamonWeygoldt, 1996. The present work has the aim to characterize Trichodamon species, update the speciesdistribution and ascertain the phylogenetic position of the genus in Phrynichidae using morphologi-cal characters. Our results show that the diagnostic characters of Trichodamon species, i.e. number ofspines on the pedipalp, shape of the frontal process, number of teeth on the chelicerae, male and femaleshape of gonopods, are highly variable. A gradual colour variation from the northern to the southernareas of the distribution is also present. In face of the high variability, the synonymy of Trichodamonfroesi (syn. jun.) with T. princeps is suggested. The cladistic analysis recovered Trichodamon as sister toPhrynichus + Euphrynichus in the subfamily Phrynichinae supported by eight characters, one exclusive tothe group (dorsal spines on pedipalp patella positioned on the apex of the article forming the phrynichhand). In Damoninae, Phrynichodamon Weygoldt, 1996 was found as sister to Damon, forming the tribeDamonini, a group supported by the number of ventral spines on pedipalp femur; Musicodamon wasrecovered as sister to Damonini, forming the subfamily Damoninae, and the clade can be recognizedby the presence of sclerotization on the apex of the claw-like projection of the female gonopod. Theunranked taxon Euphrynichida Weygoldt, 2000 (Phrynichinae + Damoninae) was recovered with goodsupport and is identified by the rectangular shape of the female gonopod and by the presence of onespine on the proximal series on pedipalp femur.