Large-scale phylogeny of chameleons suggests African origins and Eocene diversification

Abstract

Oceanic dispersal has emerged as an important factor contributing to biogeographic patterns in numerous taxa. Chameleons are a clear example of this, as they are primarily found in Africa and Madagascar, but the age of the family is post-Gondwanan break-up. A Malagasy origin for the family has been suggested, yet this hypothesis has not been tested using modern biogeographic methods with a dated phylogeny. To examine competing hypotheses of African and Malagasy origins, we generated a dated phylogeny using between six and 13 genetic markers, for up to 174 taxa representing greater than 90 per cent of all named species. Using three different ancestralstate reconstruction methods (Bayesian and likelihood approaches), we show that the family most probably originated in Africa, with two separate oceanic dispersals to Madagascar during the Palaeocene and the Oligocene, when prevailing oceanic currents would have favoured eastward dispersal. Diversification of genus-level clades took place in the Eocene, and species-level diversification occurred primarily in the Oligocene. Plio-Pleistocene speciation is rare, resulting in a phylogeny dominated by palaeo-endemic species. We suggest that contraction and fragmentation of the Pan-African forest coupled to an increase in open habitats (savannah, grassland, heathland), since the Oligocene played a key role in diversification of this group through vicariance.

No longer single! Description of female Calumma vatosoa (Squamata, Chamaeleonidae) including a review of the species and its systematic position

“…vencesi Andreone, Mattioli, Jesu &Randrianirina, 2001 of the C. furcifer group, and C. boettgeri (Boulenger, 1888), C. fallax (Mocquard, 1900), C. gallus (Günther, 1877), C. guibei (Hillenius, 1959), C. linotum, C. nasutum (Duméril & Bibron, 1836, and C. vohibola Gehring, Ratsoavina, Vences & Glaw, 2011 of the C. nasutum group. Calumma cucullatum (Gray, 1831) is not considered a part of the C. furcifer group in the strict sense (see phylogeny in Tolley et al 2013). In addition C. peyrierasi was investigated according to its phylogenetic position in the C. nasutum group -but it is clearly separated from the other species of the C. nasutum group (Tolley et al 2013).…”

“…Calumma cucullatum (Gray, 1831) is not considered a part of the C. furcifer group in the strict sense (see phylogeny in Tolley et al 2013). In addition C. peyrierasi was investigated according to its phylogenetic position in the C. nasutum group -but it is clearly separated from the other species of the C. nasutum group (Tolley et al 2013). The same specimen, which was analysed genetically in Tolley et al (2013), was used for morphological measurements together with three more specimens of the same series.…”

“…In addition C. peyrierasi was investigated according to its phylogenetic position in the C. nasutum group -but it is clearly separated from the other species of the C. nasutum group (Tolley et al 2013). The same specimen, which was analysed genetically in Tolley et al (2013), was used for morphological measurements together with three more specimens of the same series. The other comparative specimens were chosen randomly, if several specimens were available, as typical representatives of their species.…”

“…These authors did not assign it to the C. nasutum group (sensu Glaw and Vences 1994), because of the absence of a rostral appendage, absence of a dorsal crest, and presence of axillary pockets. The C. nasutum group was recently found to be non-monophyletic (Tolley et al 2013) and to include C. peyrierasi, a species formerly assigned to the C. furcifer group. The hemipenis ornamentation of C. vatosoa differs from that of all other species of the genus Calumma by the coexistence of three pairs of rotulae (Andreone et al 2001).…”

“…Madagascar is a hotspot of chameleon diversity and endemism (Tolley et al 2013). Of the currently described 202 chameleon species, 86 species belong to the four Malagasy genera Brookesia Gray, 1865, Calumma Gray, 1865, Furcifer Fitzinger, 1843, and Palleon Glaw, Hawlitschek & Ruthensteiner, 2013, and all but two Comorian species of Furcifer are endemic to Madagascar (Glaw 2015).…”