Dysderina Simon is one of the largest of the classical genera of goblin spiders, containing numerous species that have been associated only because they are heavily scutate gamasomorphines with long, paired spines on the ventral surface of the anterior tibiae and metatarsi. The Old World species that have been assigned to the genus are wildly misplaced, and the New World fauna constitutes a complex of over 225 species belonging to at least nine genera. The northern Andes house a highly diverse fauna, both of Dysderina itself and of closely related genera. The new genus Scaphidysderina is established for one of those related but distinct Andean groups, characterized by a crenulated sternum and by the reduction or loss of the dorsal abdominal scutum in females. Seventeen new species are described from Peru (S. manu, S. pagoreni, S. scutata, S. cajamarca), Ecuador (S. tayos, S. loja, S. molleturo, S. tapiai, S. pinocchio, S. palenque, S. tandapi, S. napo, S. baerti, S. cotopaxi, S. andersoni), and Colombia (S. hormigai, S. iguaque). Males of several species show remarkable modifications of the chilum and chelicerae; the chilum is sometimes enlarged to form a conspicuous snout, and the cheli cerae often bear a heavily sclerotized, dorsally directed spine, A second new genus, Costarina, is established to contain the most commonly encountered species that have been misplaced in Dysderina; Dysderina plena O. P.-Cambridge, from Mexico, is chosen as the type species, and 1.5 additional taxa, all described from Central America by Chickering, are transferred from Dysderina to Costarina: D. abdita, D. belinda, D. concinna, D. dura, D. humphreyi, D. improvisa, D. intempina, D. meridina, D. obtina, D. poteria, D. recondita, D. riigida, D. seclusa, D. silvatica, and D. watina.