Phylogenetics, classification, and biogeography of the treefrogs (Amphibia: Anura: Arboranae) Author Duellman, William E. Author Marion, Angela B. Author Hedges, Blair text Zootaxa 2016 4104 1 1 109 journal article 10.11646/zootaxa.4104.1.1 9b3e7716-1099-48ca-803b-620c25d788f1 1175-5326 265809 D598E724-C9E4-4BBA-B25D-511300A47B1D Hylidae : Dendropsophinae Another major branch of neotropical hylids, the dendropsophines, split from the pseudinines in the Eocene, 44.9 (39.1–50.8) Mya, and began diversifying (crown node) in the early Oligocene, 31.9 (25.3–38.5) Mya. Initially, this group split into a clade containing two small species in the genus Xenohyla confined to coastal Brazil and the speciose genus Dendropsophus , which occurs throughout tropical South America northward to Mexico and is unique among hylids in having a chromosome complement of 2 n = 30. Several major clades are identifiable within Dendropsophus ; some of these have defined geographic limits, whereas others are widespread geographically. Among the latter are the D. marmoratus Group inhabiting the Amazon Basin, Guiana Region, and the Atlantic Coastal Forest, and the D. leucophyllatus Group ranging throughout the Amazon Basin, Guiana Region, and northward to tropical Mexico . These groups evolved in the mid-Miocene; their ages are 17.0 (12.9–21.1) Mya and 18.7 (15.7–21.6) Mya, respectively. Another large group of small species principally inhabiting the Atlantic Coastal Forest but also occurring in the Amazon Basin and Guiana Region is the D. bipunctatus Group, which also diverged in the mid-Miocene, 14.9 (10.7–19.1) Mya. Among the groups with relatively small, defined ranges are the D. labialis Group in the northern Andes and the D. microcephalus Group in Mexico and Central America . These groups originated later in the Miocene; their ages (crown node times) are 9.6 (6.8–12.3) Mya and 11.2 (8.6–13.7) Mya, respectively.