Research Article

Undersampling Taxa Will Underestimate Molecular Divergence Dates: An Example from the South American Lizard Clade Liolaemini

Table 7

Squamate fossils and dates in millions of years (mya) used as calibration points.

Date (MYA)Fossil taxonNode assigned ageReference

218–144Stem age of Iguania (maximum–minimum)This age range was chosen to include the estimated divergence dates from several recent analyses of squamate and iguanian relationships. See arguments made by authors in associated references[41, 4851]
(1)33.5Crotaphytus oligocenicus Stratigraphic age corresponding to the beginning of lower Oligocene placed at common ancestor of Crotaphytus and Gambelia ([52] (but see [53]))
(2)20Dipsosaurus sp. Stratigraphic age corresponding to approximate midpoint (16–23) of lower Miocene placed at common ancestor of Dipsosaurus and its sister group[53]
(3)2.7Sceloporus undulatus cladeApproximate midpoint stratigraphic age of Pliocene (1.8–3.6) placed at common ancestor of taxa referred to as members of Sceloporus undulatus clade and their sister group[53]
(4)14.5Sceloporus Approximate midpoint of stratigraphic age of fossil horizon (12–17 mya) placed at common ancestor of Sceloporus and its sister group[53, 54]
(5)31Paraphrynosoma greeniMidpoint stratigraphic age (28–33 mya) of fossil horizon placed at common ancestor of Phrynosoma and the sand lizard clade[55]
(6)13.5Holbrookia antigua Midpoint stratigraphic age (11–16 mya) of fossil horizon placed at common ancestor of Holbrookia and Cophosaurus [56]
(7)50.3Suzanniwana patriciana Youngest stratigraphic age of Wasatchian time period (55.8–50.3 MYA) placed at the common ancestor representing crown Corytophanidae[57]
(8)16Liolaemus sp. Approximate age of the end of the Early Eocene from with the fossil was collected placed at crown of genus Liolaemus [36, 38]
(9)16Pristidactylus sp. Approximate age of the end of the Early Eocene from with the fossil was collected placed at the common ancestor of Pristidactylus and its sister taxon[36, 38]
(10)33.9Polychrus charisticus Midpoint stratigraphic age (30.5–36.5 mya) of fossil horizon placed at common ancestor of Polychrus and its sister group [58]