Ischnocolinae and Schismatothelinae

Theraphosidae systematics has undergone some changes in the last 20 years, with many phylogenetic hypotheses supporting unforeseen relationships and several new genera described. Amongst all 11 subfamilies currently included in Theraphosidae, Ischnocolinae is the most problematic, as it was originally established based on a plesiomorphic feature, the divided tarsal scopula. A recent phylogenetic hypothesis based only on morphology showed that most of Ischnocolinae representatives do not form monophyletic units, and instead, are scattered across the family tree, except for those comprising Schismatothelinae: Sickius, Neoholothele, Guyruita, Euthycaelus, and Schismatothele. Schismatothelinae is endemic to the Neotropics and its diversity is still underestimated, as many new species are described every year. Although well sampled in phylogeny mentioned above, the status of the remaining Neotropical Ischnocolinae genera (Catumiri, Dolichothele, Acanthopelma, Holothele) are far from being resolved, as morphological characters show high degrees of homoplasy. Not until a comprehensive sampling of Ischnocolinae is achieved with molecular data, new nomenclatural acts should be further proposed. The Neotropical spiders included in Ischnocolinae and Schismatothelinae occur in all different environments across Central and South Americas. The full diversity of Neotropical Ischnocolinae, and Schismatothelinae will be considered in this chapter, with diagnoses for genera, identification keys, and pictures.