Phylogenetic relationships of elephant‐shrews (Afrotheria, Macroscelididae)

Abstract

Elephant-shrews or sengis (Macroscelidea, Afrotheria) are grouped into two subfamilies, Rhynchocyoninae with a single genus and four species, and Macroscelidinae represented by three genera and 13 species. Our current understanding of the evolutionary relationships within this group is largely based on a molecular phylogeny that suffers from incomplete species representation. We present the first complete phylogeny (with the exception of the recently described East African Rhynchocyon udzungwensis) for Macroscelidea based on mitochondrial and nuclear markers. Novel cytogenetic characters as well as previously described allozyme variation and various morphological features are evaluated and mapped to the molecular topology. Our analyses indicate that Elephantulus is paraphyletic, and that Petrodromus and Macroscelides should be subsumed in Elephantulus. A relaxed Bayesian dating approach supports the hypothesis that an arid-adapted Macroscelidinae lineage dispersed from east Africa at $11.5 MYA via an African arid corridor to south-western Africa. The timing of speciation within the east African Rhynchocyoninae (8-10 MYA) is coincidental with the diversification of some other forest specialists. In turn, divergence within the Macroscelidinae coincides with major aridification events across Africa.

Genetic diversity and spatial genetic structure of African wild dogs (Lycaon pictus) in the Greater Limpopo transfrontier conservation area

“…We conducted sequence-based typing for the mitochondrial control region (primer combination described in Leigh 2005) and cytochrome-b gene (primer combination described in Smit et al 2011); the control region allowed direct comparisons with earlier studies (Girman et al 2001;Marsden et al 2012). The PCR reactions contained 1 unit of enzyme (SuperTherm; Southern Cross Biotechnology), 20 pmol of each primer, 1x PCR Buffer, 2.5 mM MgCl2, 200 μM dNTP and ~ 10 ng of DNA product.…”

The evolution of micro-cursoriality in mammals

“…The establishment of a system of maintained trails along which the Macroscelidinae run at great speed also evolved with body size reduction and more open habitats (Rathbun, 2009). (Zack et al, 2005b;Zack et al, 2005a), Butler (Butler, 1995) and Tabuce et al (Tabuce et al, 2001), whereas that of the traditionally recognized macroscelid families follows Tabuce et al (Tabuce et al, 2007) and Smit et al (Smit et al, 2011). Note that the Aphelisidae have recently been recognized as North American ungulates basal to Euungulata (=crown Perrisodactyla and Artiodactyla) and not as macroscelids.…”

“…Thus the macroscelids show the first appearance of micro-cursoriality in a crown Eutherian order (Tabuce et al, 2007). It is estimated that the two subfamilies of elephantshrews, Macroscelidinae (Elephantulus, Petrodromus and Macroscelides) and Rhynchocyoninae (Rhynchocyon), diverged 26-43 MYA from a forest-adapted ancestor (Douady et al, 2003;Smit et al, 2011) The Rhynchocyoninae speciated ~8-10 MYA coincident with Miocene forest fragmentation induced by aridification (Smit et al, 2011) (Fig. 5).…”

“…Speciation within Macroscelidinae commenced ~11.5 MYA following dispersal from east Africa to southwestern Africa driven by the aridification of the Sahara and the creation of sub-Saharan arid corridors, and the emergence of savannas and C 4 grasslands (Fig. 5) (Douady et al, 2003;Rathbun, 2009;Smit et al, 2011). The Macroscelidinae display more derived cursorial specializations than Rhychocyon, such as a near twofold increase in the MT:F ratio (Table 6, Fig.…”

Petrosaltator gen. nov., a new genus replacement for the North African sengi Elephantulus rozeti (Macroscelidea; Macroscelididae)

“…Since the publication of the Douady et al (2003) paper, other synapomorphies of E. rozeti and Petrodromus have been discovered and provide additional independent support for a taxonomic revision. Although other authors have suggested that a revision is needed (Holroyd 2010;Smit et al 2011), to date none has been produced. Here, we test the genetic conclusions of Douady et al (2003), consider additional morphological data, and provide a revised taxonomy.…”