Phylogeny and biogeography of the African Bathyergidae: a review of patterns and processes

Abstract

Background We review genealogical relationships, biogeographic patterns and broad historical drivers of speciation within the Bathyergidae, a group of endemic African rodents, as well as identify key taxa which need further research. Methods We sourced comparable cytochrome b sequence data (comparable data available for all members for the Family) and geographic information for all six genera of the African subterranean rodent. This information was combined into the most comprehensive and geographically representative evolutionary study for the Bathyergidae to date. Results Species richness within the Bathyergidae appears to be underestimated, with undescribed taxa in five of the six genera. Biogeographic patterns suggest large historical distributions, which were repeatedly fragmented by major landscape changes (especially rifting, uplift and drainage evolution) since the Miocene. Aside from vicariant events, other factors (ecological specialization, population-level responses and climatic change) may have been instrumental in driving divergences in the Bathyergidae. As such, adaptive differences may exist among both populations and species across their discrete ranges, driving independent evolutionary trajectories among taxa. In addition, highly fragmented distributions of divergent (and often relict) lineages indicates the possibility of narrow endemics restricted to diminishing suitable habitats. From this, it is clear that a systematic revision of the Bathyergidae is necessary; such a revision should include comprehensive sampling of all putative taxa, the addition of genomic information to assess adaptive differences, as well as ecological information.

Comparative forelimb morphology of scratch‐digging and chisel‐tooth digging African mole‐rat species

“…This new classification has been accepted in several studies (Burgin, Colella, Kahn, & Upham, 2018; D'Elía, Fabre, & Lessa, 2019; Patterson, 2016; Tavares & Seuánez, 2018). However, a recent study did not support the division of the two families, Heterocephalidae and Bathyergidae (Visser, Bennett, & van Vuuren, 2019).…”

“…This new classification has been accepted in several studies (Burgin, Colella, Kahn, & Upham, 2018;D'Elía, Fabre, & Lessa, 2019;Patterson, 2016;Tavares & Seuánez, 2018). However, a recent study did not support the division of the two families, Heterocephalidae and Bathyergidae (Visser, Bennett, & van Vuuren, 2019). While an early study described the musculature of the whole body in an unknown number of B. suillus specimens (Parsons, 1896), studies on forelimb morphology of African mole-rats are lacking, especially with regard to how digging behaviour may influence limb morphology.…”

Effects of Sex and Breeding Status on Skull Morphology in Cooperatively Breeding Ansell’s Mole-Rats and an Appraisal of Sexual Dimorphism in the Bathyergidae

“…Despite their ecological uniformity and specialization, bathyergids encompass species with strongly contrasting social systems (Figure 1). The genera Bathyergus (dune mole-rats), Georychus (Cape mole-rat), and Heliophobius (silvery mole-rat) lead strictly solitary lives, while the sister genera Cryptomys (Southern common molerats) and Fukomys (Northern common mole-rats) as well as the basalmost branching FIGURE 1 | Taxonomy, sexual size dimorphism and social systems of African mole-rats following Visser et al (2019). Silhouettes indicate variation of body size between species and the degree of dimorphism between the sexes (males = black, females = gray, sexes and species only roughly set to scale for purposes of comprehension).…”

The oestrous cycle of the Damaraland mole‐rat revisited: evidence for induced ovulation

“…A closer look, however, reveals some differences between the two species. Phylogenetically, the genus Heterocephalus groups separately from the remaining five genera within the Bathyergidae (Visser et al ., 2019). Although in naked mole‐rats outbreeding is the preferred mode of mating both in the wild and in captivity, breeding vacancies can also be filled from within the colony if there are no opportunities for outbreeding (Braude, 2000; Ciszek, 2000).…”