Fukomys

Abstract: Recently, in an examination of the phylogenetic relationships among the mole-rats of the family Bathyergidae (Mammalia: Rodentia), Ingram et al. (2004) documented molecular evidence for the recognition of the Cryptomys mechowii species group at the generic level and resurrected the name Coetomys Gray, 1864 for this group. Subsequent literature review revealed that Coetomys is not available to this species group, being a junior synonym of Cryptomys Gray, 1864. Here, we describe and diagnose Fukomys genus novum. In addition, we discuss the taxonomic history of this group in an attempt to reduce the nomenclatural confusion that has plagued studies of the Bathyergidae for over a century.

Abstract: The subterranean African mole-rats (Family Bathyergidae) show considerable variation in their diploid numbers, but there is limited understanding of the events that shaped the extant karyotypes. Here we investigate chromosomal evolution in specimens representative of six genera and an outgroup species, the cane rat Thryonomys swinderianus, using flow-sorted painting probes isolated from the naked mole-rat, Heterocephalus glaber (2n = 60). A chromosomal phylogeny based on the cladistic analysis of adjacent syntenies detected by cross-species chromosome painting was not consistent with that obtained using DNA sequences due, in large part, to the conserved nature of the Bathyergus, Georychus and Cryptomys karyotypes. In marked contrast, the Fukomys and Heliophobius species showed extensive chromosome reshuffling, permitting their analysis by a computational approach that has conventionally been employed in comparative genomic studies for retrieving phylogenetic information based on DNA sequence or gene order data. Using the multiple genome rearrangements (MGR) algorithm and chromosomal rearrangement data detected among F. damarensis, F. darlingi, F. mechowi and the sister taxa B. janetta and Heliophobius argenteocinereus, cytogenetic support for the monophyly of Fukomys and a sister association for F. darlingi + F. damarensis was retrieved, mirroring the published sequence-based topology. We show that F. damarensis, a lineage adapted to arid and climatically unpredictable environments in Southern Africa, is characterized by a large number of fissions the fixation of which has probably been favoured by environmental factors and/or its particular eusocial structure.

Abstract: To better understand evolutionary pathways leading to eusociality, interspecific comparisons are needed, which would use a common axis, such as that of reproductive skew, to array species African mole-rats (Bathyergidae, Rodentia) provide an outstanding model of social evolution because of a wide range of social organizations within a single family; however, their reproductive skew is difficult to estimate, due to their cryptic lifestyle A maximum skew could theoretically be reached in groups where reproduction is monopolized by a stable breeding pair, but the value could be decreased by breeding-male and breeding-female turnover, shared reproduction and extra-group mating The frequency of such events should be higher in species or populations inhabiting mesic environments with relaxed ecological constraints on dispersal To test this prediction, we studied patterns of parentage and relatedness within 16 groups of Ansell's mole-rat (Fukomys anselli) in mesic miombo woodland Contrary to expectation, there was no shared reproduction (more than one breeder of a particular sex) within the studied groups, and proportion of immigrants and offspring not assigned to current breeding males was low The within-group parentage and relatedness patterns observed resemble arid populations of 'eusocial' Fukomys damarensis, rather than a mesic population of 'social' Cryptomys hottentotus As a possible explanation, we propose that the extent ecological conditions affect reproductive skew may be markedly affected by life history and natural history traits of the particular species and genera

Abstract: The hearing and visual ecology of mole-rats, Spalax ehrenbergi (Spalacidae) from Israel and Fukomys (formerly Cryptomys) anselli (Bathyergidae) from Zambia, two rodent taxa that have independently adapted to subterranean life, are reviewed and compared with epigeic counterparts, the laboratory rat and the guinea pig. In burrows, airborne sounds of low frequencies (200-800 Hz) are least attenuated and even accentuated over short distances. In both mole-rat species the frequency range of the best hearing is shifted to match the frequencies best propagated in tunnels: hearing sensitivity in the lower frequency range (<16 kHz) has been conserved or further improved. Compared to the rat, the hearing range (covering about eight octaves) in mole-rats is not restricted but only shifted towards lower frequencies.Morphologies of the middle and inner ears of mole-rats and the guinea pig are similar in some aspects and suggest tuning to low frequencies. The middle ear morphology of mole-rats does not seem to explain the lower high-frequency limit of hearing. Middle ear is not reduced or degenerated. On the contrary, the incus and the stapedial footplate are markedly enlarged, resulting in reduced sensitivity. These features can be considered an adaptation to compensate for local sound amplification in burrows. The cochlea and its components are highly specialised for sensitive perception and high resolution of low frequencies.Despite living in the same optic environment, Spalax and Fukomys show different degrees of regression and specialisation of the visual system. The eye in Spalax is severely regressed and shortwave-opsin cones are missing. Spalax is blind but the retina has retained its role for photoperiodic perception. Fukomys has small, yet morphologically normal, eyes, with a retina rich in 'blue' cones. It has retained basic visual capabilities; however, the role of light as a zeitgeber is not conclusive.