Multiple cenozoic invasions of Africa by penguins (Aves, Sphenisciformes)

Abstract

Africa hosts a single breeding species of penguin today, yet the fossil record indicates that a diverse array of now-extinct taxa once inhabited southern African coastlines. Here, we show that the African penguin fauna had a complex history involving multiple dispersals and extinctions. Phylogenetic analyses and biogeographic reconstructions incorporating new fossil material indicate that, contrary to previous hypotheses, the four Early Pliocene African penguin species do not represent an endemic radiation or direct ancestors of the living Spheniscus demersus (blackfooted penguin). A minimum of three dispersals to Africa, probably assisted by the eastward-flowing Antarctic Circumpolar and South Atlantic currents, occurred during the Late Cenozoic. As regional sea-level fall eliminated islands and reduced offshore breeding areas during the Pliocene, all but one penguin lineage ended in extinction, resulting in today's depleted fauna.

Phylogenetic Characters in the Humerus and Tarsometatarsus of Penguins

“…Nevertheless, several internal nodes are recovered, including the crown Spheniscidae and two new clades of stem taxa. Additionally, the internal topology and polarity of Procellariiformes and Spheniscidae are largely congruent respect to studies based on combined data (e.g., Ksepka and Thomas 2013;Ksepka et al 2012).…”

“…-As could be expected for the analyses limited to subsets of characters, the resolution of the strict consensus for all the tested sets (Fig. 4) is poorer than that in former analyses based on the full morpho− logical dataset or its combination with molecular data (e.g., Ksepka et al 2012;Ksepka and Thomas 2013). The uncorrected subset of Chávez Hoffmeister et al (2014) results in 18 most parsimonious trees (MPTs) (153 steps) (Fig.…”

“…The following characters are based on the humerus/tarsometatarsus traits used by Chávez Hoffmeister et al (2014), which in turn were modified from Ksepka et al (2012) and Ksepka and Thomas (2013). Twenty−five new characters were added for a total of 75 humerus/tarsometatarsus traits.…”

“…Currently, a vast majority of phylogenetic studies including fossil and extant taxa are based on the supermatrix of Ksepka et al (2006) and its subsequent modifications (Clarke et al 2007; Ksepka and Clarke 2010;Ksepka et al 2012;Ksepka and Thomas 2013). The most recent version of this dataset in− cluded 254 morphological characters (Chávez Hoffmeister et al 2014), of which 31 are from the humerus and 19 from the tarsometatarsus, representing 19.1% and 11.7% of the osteological characters respectively.…”

A review of Australian fossil penguins (Aves: Sphenisciformes)

“…climate change, palaeoceanography (Baker et al, 2006;Ksepka & Thomas, 2012), biogeography (Clarke et al, 2007), secondary adaptation to water (Thomas & Fordyce, 2007), and stratigraphic calibration of molecular divergence estimates (Slack et al, 2006). Thus the penguin fossil record informs broader issues in macroevolution.…”