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The endangered giant root-rat (Tachyoryctes macrocephalus, also known as giant mole rat) is a fossorial rodent endemic to the afro-alpine grasslands of the Bale Mountains in Ethiopia. The species is an important ecosystem engineer with the majority of the global population found within 1000 km(2). Here, we present the first complete mitochondrial genome of the giant root-rat and the genus Tachyoryctes, recovered using shotgun sequencing and iterative mapping. A phylogenetic analysis including 15 other representatives of the family Spalacidae placed Tachyoryctes as sister genus to Rhizomys with high support. This position is in accordance with a recent study revealing the topology of the Spalacidae family. The full mitochondrial genome of the giant root-rat presents an important resource for further population genetic studies.

Optimal functioning of the olfactory system is critical for survival of fossorial rodents in their subterranean lifestyle. This study examines the structure of the olfactory mucosa and olfactory bulb of two fossorial rodents exhibiting distinct social behaviors, the East African root rat and the naked mole rat. The social naked mole rat displayed simpler ethmoturbinates consisting of dorsomedial and broad discoid/flaplike parts that projected rostrally from the ethmoid bone. In the solitary root rat however, the ethmoturbinates were highly complex and exhibited elaborate branching which greatly increased the olfactory surface area. In addition, when correlated with the whole brain, the volume of the olfactory bulbs was greater in the root rat (4.24×10-2) than in the naked mole rat (3.92×10-2). Results of this study suggest that the olfactory system of the root rat is better specialized than that of the naked mole rat indicating a higher level of dependence on this system since it leads a solitary life. The naked mole rat to the contrary may have compensated for its relatively inferior olfactory system by living in groups in a social system. These findings demonstrate that structure of the olfactory system of fossorial mammals is dictated by both behavior and habitat.

Tachyoryctes splendens (Northeast African mole-rat) and Heliophobius emini (Emin's mole-rat) are two African mole-rats that represent separate allopatric rodent families namely Spalacidae and Bathyergidae respectively. While these species consume a similar diet of underground plant storage organs such as roots and tubers, T. splendens has been reported to additionally consume small amounts of aerial foliage. This study aims to provide detailed gross morphological and histological morphometric analyses of the gastrointestinal tract (GIT) of these two subterranean species. The formalin fixed gastrointestinal tracts of T. splendens (n = 9) and H. emini (n = 6) were photographed, weighed and measured. The length and basal surface areas were calculated for each anatomically distinct region. Representative histological samples were prepared and stained using Hematoxylin and Eosin. Microscopic luminal measurements were used to calculate a surface enlargement factor and the luminal surface area of each region. Tachyoryctes splendens had a large double chambered hemi-glandular stomach with a macroscopically visible transition from keratinized stratified squamous epithelium to glandular epithelium. The cecum was large and the luminal surface revealed a single spiral fold. The ascending colon of T. splendens was arranged in a spiral, with two centripetal and two centrifugal windings. The descending colon was arranged in a single parallel loop, similar to H. emini. A narrow colonic groove was accompanied by V-shaped folds on either side. Heliophobius emini had a simple glandular stomach, a large, haustrated cecum that displayed a cecal appendix and the descending colon was arranged in a single parallel loop. The internal aspect of the colon revealed a wide colonic groove extending from the ceco-colic junction to distal colon. As both species originate from a similar geographical region and ingest very similar diets, it is likely that the differences in the GIT morphology are attributed to phylogeny as the species represent two different families of mole-rats.

Fossorial mammals are supposed to face hypoxic and hypercapnic conditions, but such conditions have been rarely encountered in their natural burrow systems. Gas composition in burrows after heavy rains, deeper burrows and especially nest chambers, where animals usually spend most of the day, could be even more challenging than in shallow burrows. Such situations, however, have been rarely surveyed in the wild. In our study, we determined concentrations of O2, CO2 and CH4 in active burrows and nests of the giant root-rat Tachyoryctes macrocephalus, a large fossorial rodent endemic to the Afroalpine zone of the Bale Mountains in Ethiopia. We were able to determine the precise location of nests by tracking individuals equipped with radio-collars. To the best of our knowledge, this is the first study that analyses air samples taken directly from the nests of actually occupied burrow systems in any free-living fossorial mammal. We found no evidence for environmental hypoxia in the examined burrows and nests (range 19.7–21.6% O2). Concentrations of CO2 in the burrows increased after the burrows were plugged in the evening, but did not reach physiologically problematic levels. The highest CO2 concentrations in burrows were detected in the evening during a wet period (up to 0.44%). In root-rat nest chambers, the highest (but still harmless) CO2 concentrations (up to 1.31%) were detected in the morning (measured in the late dry season only) together with an elevated concentration (up to 13.5 ppm) of CH4. Regular surface activity of giant root-rats, combined with the relatively large dimensions of their nest chambers and tunnels, and the absence of heavy soils, may contribute to harmless atmospheres within their burrow systems.

The East African root rat (Tachyoryctes splendens (Rüppell, 1835)) is a solitary subterranean rodent that exhibits a marked seasonal reproduction linked to the bimodal rainfall pattern of East Africa. The current study sets out to determine whether the East African root rat is an induced or spontaneous ovulator. Five wild caught adult females were monitored noninvasively for ovarian cyclicity by measuring urinary progesterone every 2 days over a period of 120 days. Females were subjected to three different experimental treatments, namely, initially singly housed or control (C), nonphysical contact with a male (NPC), and physical contact with a vasectomised male (PC), respectively. The concentration of urinary progesterone was higher during PC than during either NPC or C. The act of coitus appears to be necessary for ovulation to occur in the females. The male East African root rats were found to possess epidermal spines on the penis that can be used to bring about cervical stimulation during coitus. The spines result in the induction of ovulation as has been proposed for other solitary subterranean rodents. The findings from the female progesterone profiles and the assessment of penile morphology suggest that the female East African root rat is an induced ovulator stimulated by penile intromission during coitus.

This study develops a new proxy for Quaternary temperature change in tropical Africa through analysis of size variation in East African mole-rat (Tachyoryctes splendens). In modern mole-rats, mandibular alveolar length is unrelated to annual precipitation, precipitation seasonality, temperature seasonality, or primary productivity. However, it is inversely correlated with mean annual temperature, in agreement with Bergmann's rule. This relationship is observed at temperatures below ∼17.3 °C, but not at higher temperatures. We apply these observations to late Quaternary mole-rats from Wakondo (∼100 ka) and Kisaaka (∼50 ka) in the Lake Victoria region and Enkapune ya Muto (EYM; ∼7.2–3.2 ka) in Kenya's central rift. The Lake Victoria mole-rats are larger than expected for populations from warm climates typical of the area today, implying cooler temperatures in the past. The magnitude of temperature decline needed to drive the size shift is substantial (∼4–6 °C), similar in magnitude to the degree of change between the Last Glacial Maximum and Holocene, but is consistent with regional temperature records and with scenarios linking equatorial African temperature to northern hemisphere summer insolation. Size changes through time at EYM indicate that rising temperatures during the middle Holocene accompanied and potentially contributed to a decline in Lake Naivasha and expansion of grassland vegetation.

Faunal studies of rodent assemblages from the areas on and around Choke Mountain (north-western Ethiopia) were conducted during two field seasons in 2012 and 2018. Here we present results of a genetic study of nine rodent species, and evaluate their genetic diversity and evolutionary relationships between conspecific populations from neighbouring montane massifs. Results of comparative analysis of phylogeographic patterns in Lophuromys, Desmomys, Stenocephalemys and Tachyoryctes have emphasized the role of the Blue Nile gorge as a strong biogeographic barrier, separating “northern” and “southern” independently evolved populations. Results of genetic analysis also revealed the presence of a new taxon of Dendromus, presumably belonging to a new species. Our study allows re-evaluation this area as an important “hotspot” of Ethiopian small mammal biodiversity.

The morphology of the hyoid, laryngeal and pharyngeal regions of the following rodent genera was studied: Cryptomys, Bathyergus, Georychus, Heliophobius, Heterocephalus, Ctenomys, Petromus, Thryonomys, Geomys, Cannomys, and Tachyoryctes. A number of morphological conditions unique to bathyergids, and associated with the use of the head and lower incisors in burrowing are described. The conditions include the formation of functional complexes of MM. sterno-geniohyoideus and omo-mylohyoideus, the presence of a unique deep oblique part of M. transversus mandibulae and a strong separate slip of M. platysma myoides pars mentalis. The hyoid skeleton is modified to allow the muscle complexes to act independently of the basihyal bone, and to allow the unusually protrusible tongue to be withdrawn. The nerves of the jugular foramen do not form a true pharyngeal plexus, and their configuration is influenced by the absence of a well developed internal carotid artery in hystricognaths. The morphology of the regions studied indicates a natural grouping of bathyergids, but one in which Heterocephalus is somewhat separate from the remaining bathyergid genera. The grouping of bathyergids and New and Old World hystricognath rodents into a suborder Hystricognatha is supported.

17. Giant Root Rat Tachyoryctes macrocephalus French: Rat-taupe géant / German: Riesenmaulwurfsratte / Spanish: Rata de raices gigante Other common names: Big-headed Mole-rat, Giant Mole-rat Taxonomy. Rhizomys macrocephalus Ruppell, 1842, Shoa, Ethiopia. Presence of 71. macrocephalus in the region known until 1995 as Shoa (= Shewa) Province, Ethiopia, is considered suspect. D. W. Yalden and M. J. Largen in 1992 suggested that type material was collected in Begemdir or Wollo Province in northern Ethiopia. No further records of 7. macrocephalus have been recorded from northern Ethiopia since the original description. In a cladistics analysis that included fossil and extant taxa, R. Lopez-Antonanzas and H. B. Wesselman in 2013 showed that the two living root rats are sister taxa with respect to the known fossil species 71. konjiti, 1 pliocaenicus, and 1. makooka. Two subspecies recognized. Subspecies and Distribution. T. m. macrocephalus Ruppell, 1842 — N Ethiopia; no records since original description. T. m. hecki Neumann & Rummler, 1928 — S Ethiopia, Bale Mts above 3000 m (Oromia Region). Descriptive notes. Head-body 224-313 mm, tail 40-65 mm; weight 330-930 g. The Giant Root Rat is stocky and short-limbed, with relatively large head and shorttail. It has soft dense pelage that is silver, brown, or orange. Hairs are gray at bases. Up to three darker lines may be present on crown of head, and dark spot is present on eyelids. Interorbital width is narrow, causing eyes to be distinctively high on face. Subspecies heck: has longer (greater than 7 mm) anterior palatal foramen and zygomatic plate that slopes down to premaxillary-maxillary suture than the nominate subspecies. Large orange incisors are visible externally when mouth is closed. Diploid numberis 2n = 50. Habitat. Restricted to alpine grassland habitat at elevations of 3000-4150 m. The Giant Root Rat prefers soil depths greater than 50 cm in swamp shore grasslands and mixed herbaceous moorlands. Moist soils are preferred. In the Bale Mountains of Ethiopia, the African Root Rat (7. splendens) is replaced by the Giant Root Rat at elevations above 3000 m. Food and Feeding. The Giant Root Rat feeds on grasses and forbs such as Festuca (Poaceae) and Alchemilla (Rosaceae). Food is gathered by opening a hole to the surface and consuming plant material within easy reach of the opening. An individual usually keeps its hindquarters in the opening to facilitate quick escape into the burrow. When food in an area is depleted, the Giant Root Ratseals the opening and creates a new burrow elsewhere. A mouthful of food is collected in short foraging bouts of 6-8 minutes and is taken belowground for consumption. Breeding. Little information is available. Female Giant Root Rats appear to have one young perlitter. Activity patterns. The Giant Root Rat is diurnal and active from 08:00 h to 16:00 h. Aboveground activity comes in short bursts, roughly ten bouts in dry season adding up to an hour of activity, with fewer during rainy season. Movements, Home range and Social organization. Only a single Giant Root Rat is present in each burrow system. Burrows are up to 90 m long and 12-15 cm in cross section belowground, with openings c.8 cm. An individual's burrow system may be up to 360 m*. All burrow entrances are closed nightly. Densities of 6 ind/ha, 24 ind/ha, 60 ind/ha, and 90 ind/ha have been reported. The ground can feel spongy when Giant Root Rats occur at high densities because ofits burrows. It may reach 50-60% of total rodent biomass in certain locations. The Giant Root Rat is a preferred prey of the Ethiopian Wolf (Canis simensis), representing up to 47% (by volume) of its diet. Other predators include owls and probably raptors. Status and Conservation. Classified as Endangered on The IUCN Red List. The Giant Root Rat can be present in very high concentrations, butits distribution is restricted and is dependent on a unique ecosystem. Much of its known distribution is in Bale Mountains National Park, but overgrazing by livestock threatens grasslands. It is not clear if the northern subspecies, macrocephalus, persists. Bibliography. Corti & Lavrenchenko (2008), Lopez-Antonanzas & Wesselman (2013), Monadjem et al. (2015), Sillero-Zubiri et al. (1995a), Yalden (1985, 2013a), Yalden & Largen (1992)., Published as part of Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Spalacidae, pp. 108-142 in Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona :Lynx Edicions on page 137, DOI: 10.5281/zenodo.6609100

16. African Root Rat Tachyoryctes splendens French: Rat-taupe est-africain / German: Ostafrika-Maulwurfsratte / Spanish: Rata de raices africana Other common names: East African Mole-rat Taxonomy. Bathyergus splendens Ruppell, 1835, Gondar, Dembea Province, Ethiopia. Excluding 1. macrocephalus, which is widely recognized as a distinct species, 19 named forms of Tachyoryctes have been described. G. G. Musser and M. D. Carleton in 2005 recognized twelve of these as distinct species, albeit with hesitation due to absence of studies assessing variation in the genus. They recognized ankoliae named by O. Thomas in 1909 from south-western Uganda and north-western Tanzania; annectans named by Thomas in 1891 from south-western Kenya; audax named by Thomas in 1910 from Aberdare Range, Kenya; daemon named by Thomas in 1909 from northern Tanzania; ibeanus named by Thomas in 1900 from southern Kenya; naivashae named by Thomas in 1909 from south-central Kenya; rex named by E. Heller in 1910 from Mount Kenya; ruandae named by E. Lonnberg and N. Gyldenstolpe in 1925 from eastern DR Congo, Rwanda, and Burundi; rudd: named by Thomas in 1909 from south-western Kenya, south-western Uganda, and north-western Tanzania; spalacinus named by Thomas in 1909 from Mount Kenya area; storey: named by Thomas in 1909 from southwestern Kenya; and splendens that they restrict to Ethiopia, Somalia, and north-western Kenya. Numerous approaches have been proposed to deal with diversity within 7. splendens, with one, seven, ten, twelve, and 14 species recognized by various authorities. In one of the only genus-wide assessments of morphological diversity, F. Beolchini and M. Corti in 2004 used geometric morphometrics and concluded that these should be treated as a single species. A. Monadjem and colleagues in 2015 highlighted the large size of rex and rejected the single species argument put forth by Beolchini and Corti. Their taxonomic treatment recognized twelve species, but they suggested that certain species warrant synonymizing. They specifically suggest that daemon, ibeanus, narvashae, and storeyi might be conspecific and that annectans and audax might also be the same species. Musser and Carleton in 2013 adopted the single species approach pending further study, which is followed here. Considerable diversity is clearly present within what is treated as 7. splendens, but arguments supporting specific systematic treatments have been very weak. L.. A. Lavrenchenko and colleagues in 2014 conducted the only molecular phylogenetic study to date on diversity within 7. splendens sensu lato. Their research was limited to Ethiopian populations and the cytochrome-b gene, but they still recovered four clades exhibiting species-level mitochondrial divergence. There is little doubt that additional study will recover instances of cryptic speciation across allopatric populations found throughout the distribution of 7. splendens. At present, however, available data do not appear to provide support for any particular taxonomic delineation proposed to date. Further study is needed. Monotypic. Distribution. Disjunct distribution in East Africa, known from Ethiopia, NW Somalia, S Uganda, SW Kenya, E DR Congo, Rwanda, Burundi, and N Tanzania. Descriptive notes. Head-body 159-268 mm, tail 49-95 mm; weight 140-330 g. Male African Root Rats are often slightly larger than females. They are robust and stocky, with short limbs. They are smaller than Giant Root Rats (7. macrocephalus). Color ranges from ginger, cinnamon-brown,to black with lighter venter. Many individuals have white patches. Juveniles are usually black. Pelage color varies in different regions. Size also varies, although these differences might occur along ecological gradients and might not reflect taxonomic differences. Large orange incisors are visible externally when mouth is closed. Third digit on forelimbis longest; first digit is rudimentary. There are eight nipples: 2 pairs of pectoral + 2 pairs of inguinal. Diploid number is 2n = 48 or 50. Habitat. Well-drained soils in savanna grasslands, and open forests in Afro-montane, Afro-alpine, and adjacent regions in East Africa. The African Root Rat occurs at elevations of 700-4150 m and is known from the highest mountains in Kenya and Tanzania. It is replaced by the Giant Root Rat at elevations above 3000 m in the Bale Mountains of Ethiopia. It is a pest of agricultural fields and gardens. It is usually found where annual rainfall is above 500 mm. Food and Feeding. The African Root Rat eats stems and leaves, herbs, grass rhizomes, roots, bulbs, and tubers. Food plants are accessed from below or by digging a feeding opening. Entire plants may be pulled down into the burrow and carried to the nest for eating or storage. When feeding at the surface, a small foraging opening is made, and an individual collects plant material within easy reach. Foraging holes are plugged with dirt after an individual goes belowground. Dirt is brushed from plants with forelimbs while being held with incisors. Breeding. Breeding of African Root Rats occurs year-round, but pregnant females are most numerous at the end of the rainy season. One to four young are born after gestation of 46-49 days. Young weighing 11-18 g are born naked and toothless, with eyes closed. They are weaned after c.35 days and establish their own burrows after c¢.80 days. Sexual maturity is reached at ¢.120 days. Females can become pregnant while nursing a previous brood. Average time betweenlitters is c.173 days. Activity patterns. The African Root Rat is reported to be diurnal in the wild, active from 10:00 h until 19:00 h. Under laboratory conditions, however, it shows distinct preference for nocturnal activity. Individuals remain in burrows more than 75% of the time. It is a chisel-tooth digger, dislodging soil with extrabuccal incisors. Dirt is held while carried to the surface by being pressed between side of head and forelimb, and a mound is formed. Burrow temperatures in Kenya are ¢.23°C; decomposition of feces and food stores provides added heat. If exposed to temperatures above 30°C, the African Root Rat salivates and spreads saliva on its body for evaporative cooling. Long-term exposure to temperatures above 35-37°C is lethal. Movements, Home range and Social organization. Burrow systems of African Root Rats are 15-44 m long and include foraging burrows, a nest chamber and a bolt-hole. Nest chambers include spaces for sleeping, food storage, and use as a toilet. Burrows are not shared, and individuals aggressively defend them. Individuals communicate seismically by tapping on burrow floors with upper incisors or on ceilings with heads. Neighbors respond with their own taps, patterns that appear specific to individuals. Individuals respond to threats by throwing their heads back, opening their mouths, and lunging forward while squeaking, snorting, and chattering teeth. Male African Root Rats emit a musk-like odor from glands beneath eyes and ears. The African Root Rat is patchily distributed, but where it is present, it can be abundant. Densities of 70-200 ind/ha have been reported. The African Root Rat is preyed on by common barn-owls (7yto alba), raptors, small carnivores, and snakes. Status and Conservation. Classified as Least Concern on The IUCN Red List. The African Root Rat is common and can be found in protected areas. Resolution of taxonomic uncertainty for the African Root Rat is essential for prioritizing conservation concerns. It is an agricultural and horticultural pest, damaging cassava, sweet potato, peanut, lucerne, and maize crops, along with lawns and young trees. Bibliography. Allen (1939), Beolchini & Corti (2004), Delany (1975), Ellerman (1941), Heller (1910), Hollister (1919), Hrouzkova et al. (2013), Jarvis (1969, 1973a, 1973b, 2013a, 2013b), Jarvis & Sale (1971), Katandukila et al. (2013), Lavrenchenko et al. (2014), Lonnberg & Gyldenstolpe (1925), McNab (1966), Misonne (1974), Monadjem et al. (2015), Musser & Carleton (1993, 2005, 2013a, 2013c), Schlitter, Agwanda & Corti (2008), Thomas (1891a, 1900a, 1909, 1910a)., Published as part of Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Spalacidae, pp. 108-142 in Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona :Lynx Edicions on pages 136-137, DOI: 10.5281/zenodo.6609100

Root-rats of the genus Tachyoryctes (Spalacidae) are subterranean herbivores occupying open humid habitats in the highlands of Eastern Africa. There is strong disagreement about species diversity of the genus, because some authors accept two species, while others more than ten. Species with relatively high surface activity, the giant root-rat Tachyoryctes macrocephalus, which is by far largest member of the genus, and the more fossorial African root-rat Tachyoryctes splendens, which eventually has been divided up to 12-13 species, represent two major morphological forms within the genus. In our study, we carried out a multilocus analysis of root-rats' genetic diversity based on samples from 41 localities representing most of Tachyoryctes geographic distribution. Using two mitochondrial and three nuclear genes, we found six main genetic clades possibly representing separate species. These clades were organised into three basal groups whose branching is not well resolved, probably due to fast radiation in the late Pliocene and early Pleistocene. Climatic changes in that time, i.e. fast and repeated changes between extremely dry and humid conditions, which both limited root-rat dispersal, probably stimulated their initial genetic diversification. Contrary to expectation based on the largest root-rat diversity in Kenya (up to eight species by some authors), we found the highest diversity in the Ethiopian highlands, because all but one putative species occur there. All individuals outside of Ethiopia belong to a single recently diverged and expanded clade. This species should bear the name T. annectens (Thomas, 1891), and all other names of taxa described from outside of Ethiopia should be considered its junior synonyms. However, to solve taxonomic issues, future detailed morphological analyses should be conducted on all main clades together with genetic analysis of material from areas of their supposed contact. One of the most interesting findings of the study is the internal position of T. macrocephalus in T. splendens sensu lato. This demonstrates the intriguing phenomenon of accelerated morphological evolution of rodents occupying the Afroalpine zone in Ethiopia. Finally, we discuss how the distribution of Tachyoryctes is influenced by competition with another group of subterranean herbivores on the continent, the African mole-rats. We assume that both groups do not compete directly as previously expected, but specialisation to different subterranean niches is the main factor responsible for their spatial segregation.

Genetic and cytogenetic variation of African root-rats Tachyoryctes splendens sensu lato from Ethiopia was assessed on 23 complete cytochrome b gene sequences (1140 bp) and chromosomal sets from eight individuals. Results of this study suggest that the real diversity of Ethiopian Tachyoryctes splendens s.l. has been underestimated due to its apparent cryptic diversification. The molecular genetic analysis reveals genetic subdivision including at least four allopatric and deeply divergent mitochondrial lineages, restricted to the Simien Mountains and the Northern, Southern and Eastern parts of the Ethiopian Plateau. Three of them possess unique karyotypes while chromosomal characteristics of the Eastern lineage remain unknown. These lineages may represent distinct species, however additional analyses of molecular, chromosomal and morphological data should be conducted to confirm our preliminary results and provide a real basis for species delimitation within Ethiopian Tachyoryctes splendens s.l.

The East African root rat (Tachyoryctes splendens) is a solitary fossorial rodent occurring in the eastern parts of central Africa. Unlike bathyergid mole-rats, T. splendens occasionally goes aboveground to feed and consequently it is periodically exposed to the natural light–dark cycle. The locomotor activity of T. splendens was assessed under various light regimes. T. splendens entrains its activity to light cycles and displays distinct nocturnal activity with the total percentage of activity during the dark phase at 87.78% ± SD 11.01%. In constant darkness, T. splendens shows free-running rhythms of slightly shorter than 24 h (2340 ± SD 013 h), while still exhibiting most of its activity during subjective night. Upon inversion of the light cycle, time of reentrainment was exceptionally long. Nocturnal activity time (α) was shortened in response to a shorter night length from 1129 to 0746 h; however, when the dark phase was lengthened, α remained roughly similar to that of the 12L:12D photoperiod at 1124 h. A difference in circadian activity is apparent from the laboratory and field findings, thus in a natural situation, other environmental factors may influence activity patterns.

University of Dar es Salaam [UDSM–World Bank Fund (C1B1) ], Tanzania.South African Department of Science and Technology (DST)/National Research Foundation (NRF) SARChI Chair for Mammal Behavioural Ecology and Physiology, University of Pretoria.

We describe the production of substrate-borne vibrations in a subterranean mole rat of the genus Tachyoryctes for the first time. These signals with a supposed communication function were recorded using two approaches. Firstly, we recorded the production of spontaneous substrate-borne vibrations of individual test animals in artificial tunnels simulating a mole rat burrow system. Secondly, we recorded substrate-borne vibrations in individuals with interconnected home systems divided by a barrier. We found that Tachyoryctes produces these seismic signals by striking its head against the ceiling of the tunnel. Two types of seismic signals differing in physical parameters were identified. A slow signal (inter-pulse distance 0.12 s, inter-bout distance 3.89 s, number of pulses within each bout 9.53) was produced in both experiments, whereas a fast signal (inter-pulse distance 0.05 s, inter-bout distance 18.44 s, number of pulses within each bout 22.54) was produced mainly in close proximity to another individual. Our results indicate that fast signals are probably individually specific, because the success rate of classification according to discriminant function analysis was 70.4 % for the three tested individuals.

The Rhizomyinae is a subfamily of myomorph rodents within the family Spalacidae. It is subdivided into two tribes: the Asian Rhizomyini and the Tachyoryctini. Even though the origin of the Tachyoryctini is to be found in Asia, they are nowadays restricted to Africa. African Tachyoryctini are known from the Late Miocene and include a single genus with five species: the recently discov- ered Tachyoryctes makooka, which is described in detail in this work, T. pliocaenicus, T. konjiti and the two extant T. splendens and T. macrocephalus. Their closest Asian coun- terparts are the Late Miocene Protachyoryctes and Eicooryc- tes. A cladistic analysis involving all the above-mentioned taxa was carried out. Protachyoryctes tatroti turned out to be the most basal species of the ingroup followed by the Ethiopian T. makooka. Both taxa show some primitive traits like the protosinus on the first upper molars, short but dis- tinct mesolophids on the lower molars and the presence of the mure on the cheek teeth. T. pliocaenicus and the most derived Tachyoryctini share the synapomorphic reduction or loss of these characters. The increase in hypsodonty evi- denced in this lineage is correlated with the transition from a humid to a drier climate that started at the beginning of the Pliocene.

The taxonomy and systematic status of the African fossorial rodent Tachyoryctes was assessed using geometric morphometric analyses of the skull. 522 specimens from the 11 species currently recognised were grouped in 31 operational taxonomic units. Skull size and shape were analysed after Procrustes analysis of two dimensional landmarks collected over its dorsal and ventral sides. No significant effect of age and sex were observed. Size allows the recognition of one taxon only, i.e. T. macrocephalus, while shape differences are significant for the majority of the comparisons. Furthermore, as a general pattern, two‐block partial least squares analysis identifies a strong relationship of size and shape with geographical and ecological parameters. Changes in size and shape appear to reflect adaptations to local climate and current conditions, and size apparently increases according the Bergmann's rule. Out of the 11 recognised species, these results confirm only the specific status of T. macrocephalu...

The cardiac portion of the stomach is lined with macrovilli in a few rodent genera. These are Mystromys (Cricetinae, Cricetidae), Myospalax (Myospalacinae, Cricetidae), Tachyoryctes (Tachyoryctinae, Cricetidae), and Cryptomys(Bathyergidae). The macrovilli favor the development of symbiotic flora and are called symbiovilli. Growth of the corneal epithelium of the cardiac portion of the stomach serves as a morphological basis of symbiovilli. Cases of a hereditary malignant neoplasm giving rise to the formation of multiple macrovilli in the cardiac portion of the stomach have been found in Microtus abbreviatus (Microtinae, Cricetidae), a vole endemic to St. Matthew Island in the Bering Sea. The macrovilli resulting from the papillomatosis mutation are morphologically and histologically identical to the macrovilli of the stomach of the four aforementioned genera. The voles affected with papillomatosis still survive long enough to reproduce. Therefore, the macromutation that leads to death in adult and old voles has been fixed as a species character in some rodent genera. At the early stages of papillomatosis, the pathogenic morphogenesis creates favorable conditions for the development of symbiotic microflora, which gives a selective advantage to the affected animals. It is assumed that mutations with pathogenic effects have been fixed as a species character as a result of heterochrony. The pathogenic neoplasm serves as a preadaptation for the growth of symbiotic flora in the stomach. The mechanisms of the fixation of Goldschmidt's “systemic mutations” during phylogeny are discussed.

The masticatory muscles and related apparatus of the hoary Rhizomys pruinosus and lesser bamboo rats Cannomys badius from Thailand, and the East African mole rat Tachyoryctes splendens from Ethiopia were morphologically examined and compared. The zygomatic arch was found to be robust in the two Asian species, with well-developed superficial, intermediate, lateral, and caudal parts of the deep layer of the masseter muscle. The temporal muscle was not well-developed in the hoary bamboo rat. The well-developed infraorbital foramen in the East African mole rat is consistent with the significant role of the medial part of the deep layer of the masseter muscle. These findings reveal that the Asian and African lineages are obviously different in terms of their masticatory systems, and indicate that the different taxa have evolved independently. These evolutionarily divergent taxa appear to represent examples of functional convergence in their similar adaptations to digging behavior and to a fossorial lifestyle.

The Ethiopian wolf ( Canis simensis ) is a rare and endangered carnivore found in only a few mountain ranges of the Ethiopian highlands. We studied its diet and feeding behavior in Bale Mountains National Park, Ethiopia, from 1988 through 1992. Observations of foraging behavior ( n = 380) and scat analysis ( n = 689) suggested that the Ethiopian wolf specializes in eating rodents. Rodents accounted for 96% of the prey occurrences and 97% volume in the droppings. The giant molerat ( Tachyoryctes macrocephalus ) was the main food item, followed in importance by three species of rats ( Arvicanthis blicki, Lophuromys melanonyx , and Otomys typus ). Ethiopian wolves foraged solitarily throughout the day, but occasionally small packs (≤6) hunted hares, young antelopes, and sheep. During food-choice experiments, wolves significantly preferred Tachyoryctes to Arvicanthis and Lophuromys , Arvicanthis to Lophuromys , and either of them to Stenocephalemys , which was invariably discarded. Lepus starcki was preferred to any of the species of rats. The contribution of different species of prey to the diet of the Ethiopian wolf correlated with abundance of prey.

Received February 2, 2012; accepted March 15, 2012 ; previously published online May 13, 2012, Tachyoryctes , the most derived genus within the tribe Tachyoryctini (Rhizomyinae, Spalacidae, Rodentia), is known from Pliocene to Recent. It comprises four species: the fossil T. pliocaenicus and T. konjiti and the extant T. splendens and T. macrocephalus . A detailed description of the morphology and dental wear pattern of the cheek teeth of T. splendens is provided based on the study of 297 skulls. For the first and second lower and upper molars, fi ve stages of wear are recognized (0 – 4). The third lower and upper molars show four stages of wear (0 – 3). The dental wear pattern in T. splendens is comparable to that of the Pleistocene T. konjiti., My sojourn in Berlin and Paris were funded by the SYNTHESYS Project (http://www.synthesys.info/ ), which is financed by European Community Research Infrastructure Action under the FP7 “Capacities” Program and by the EDIT Gender Action Plan, respectively., My research is currently supported by the Ramón y Cajal Program and the research project CGL2011-24829.

This PhD. thesis focuses on the vibrational communication of subterranean mammals, in particular, vocal communication of bathyergids (Heliophobius argenteocinereus, Fukomys mechowii, Fukomys darlingi) and seismic communication of Tachyoryctes. We recorded and analyzed the vocalization of three species and discussed the physical parameters of their vocalization in relationship to the special underground acoustic environment. Moreover, social systems of African mole-rats range from solitary to eusocial and thus our results enabled us to discuss the influence of sociality on vocal repertoire richness and its composition. Long distance communication possesses many challenges in underground environments; the only effective mean is seismic communication. We described for the first time seismic signaling in Tachyoryctes and proposed its function.

The new karyotypic form of Tachyoryctes splendens (Ruppell 1836) from Ethiopia is described. It consists of 48 chromosomes, of which three pairs (1, 2, 4) are subtelocentric with very short additional arms, 17 pairs are acrocentric and three pairs are metacentric. The sex pair is composed of the largest submetacentric X-chromosome and large metacentric Y-chromosome. The fundamental number is 62. C-banding reveals pericentromeric heterochromatin in almost all autosomes and X- chromosome, additional heterochromatic blocks at the short arms of subtelocentric autosomes, telomeric blocks of X-chromosome and fully heterochromatinized Y-chromosome. The Ag-NORs are localized at the telomeric ends of the short arms of the first and the second autosomal pairs. The data on T. splendens of Ethiopia are compared with those from earlier studies of the karyotypes of representatives of the family Rhizomyidae to which T. splendens belongs.

The lungs of two fossorial rodents, the mole ratTachyoryctes splendens and the naked mole ratHeterocephalus glaber were investigated by transmission and scanning electron microscopy and a comparative morphometric analysis of the lungs carried out in an attempt to find out whether there are any possible structural adaptational features which may be associated with fossoriality. The data from these two ecologically disparate fossorial rodents were compared with those of surface dwelling rodents on which equivalent data are available. Morphologically, the lung ofT. splendens is essentially similar to that of terrestrial mammals while that ofH. glaber shows features of underdevelopment. InH. glaber, a cuboidal epithelium extends down the respiratory tree to line what appear to be alveolar spaces, the blood capillaries constitute a double capillary system and the type I pneumocytes have microvilli on their free surface. Morphometrically,H. glaber has notably lower values indicative of rather unspecialized lungs. While the volume density of the parenchyma is 88% inT. splendens, that inH. glaber is only 76%. The blood-gas (tissue) barrier inH. glaber is notably thicker than inT. splendens. When normalized with body weight, the surface area of the blood-gas (tissue) barrier, the pulmonary capillary blood volume, the diffusing capacities of the tissue barrier and of the whole lung are consistently appreciably lower inH. glaber. When compared withMus musculus, Rattus rattus andCavia porcellus, T. splendens has somewhat comparable values with the surface dwelling rodents but the values ofH. glaber are the lowest in the group. It is suggested thatT. splendens has not undergone full adaptation to fossoriality as is supported by its behavioural activities, particularly those of occasionally surfacing to feed and making overland excursions. The low values ofH. glaber may be commensurate with its extreme physiological adaptations for fossoriality, features which culminate in low basal metabolism and may in part explain paedomorphic traits of its respiratory system.

There is evidence that spalacine, tachyoryctine, and myospalacine mole-rats all communicate with conspecifics through a form of seismic signaling, but the route for the detection of these signals is disputed. It has been proposed that two unusual anatomical adaptations in Spalax allow jaw vibrations to pass to the inner ear via the incus and stapes: a pseudoglenoid (=postglenoid) fossa which accomodates the condylar process of the mandible, and a bony cup, supported by a periotic lamina, through which the incus articulates with the skull. In this study, a combination of dissection and computed tomography was used to examine the ear region in more detail in both Spalax and its subterranean relatives Tachyoryctes and Eospalax, about which much less is known. Tachyoryctes was found to lack a pseudoglenoid fossa, while Eospalax lacks a periotic lamina and bony cup. This shows that these structures need not simultaneously be present for the detection of ground vibrations in mole-rats. Based on the observed anatomy, three hypothetical modes of bone conduction are argued to represent more likely mechanisms through which mole-rats can detect ground vibrations: ossicular inertial bone conduction, a pathway involving sound radiation into the external auditory meatus, and a newly-described fluid pathway between pseudoglenoid fossa and cranial cavity. The caudolateral extension of the tympanic cavity and the presence of a bony cup might represent synapomorphies uniting Spalax and Tachyoryctes, while the loss of the tensor tympani muscle in Spalax and Eospalax may be convergently derived. J. Morphol., 2010. © 2009 Wiley-Liss, Inc.

Summary The morphogenesis of the foetal membranes and placenta of the root-rat Tachyoryctes splendens was studied by light microscopy. Implantation of the blastocyst is antimesometrial. The mode of implantation is secondary interstitial and the decidual reaction is similar to that in other rodents. Amniogenesis is by cavitation with a temporary open epamniotic cavity. Inversion of the yolk sac is complete but the disappearance of the parietal segment occurs relatively late. With the breakdown of both the decidua capsularis and parietalis, the yolk sac wall near the margins of the placenta becomes bathed in a pool of maternal blood and tissue debris resembling the haemophagous organ. The yolk sac villi are well vascularized. The allantoic cavity is persistent up to the limb bud stage. The definitive placenta is haemochorial and shows conspicuous endodermal sinuses or placental pits.

Tachyoryctes splendens (Rüppell, 1835). Neue wirbelt. Fauna Abyssin. Gehörig., Säugeth., 1:36. TYPE LOCALITY: Ethiopia, Dembea Prov, Gondar. DISTRIBUTION: Ethiopia (500-3900 m; Rupp, 1980), Somalia, and NW Kenya; limits unknown. SYNONYMS: canicaudus, cheesmani, gallarum, ibeanus, omensis, pontifex, somalicus. COMMENTS: Yalden et al. (1976) claimed that the synonyms (except for ibeanus) listed here clearly apply to one species. Osgood (1936), however, noted that two species, splendens and cheesmani, could be distinguished among the Ethiopian samples he examined. We include ibeanus because it is geographically close to the range of T. splendens and was originally described as a subspecies of that species (see Allen, 1939). Hollister (1919) identified series from SE Kenya as T. ibeanus., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 687, DOI: 10.5281/zenodo.7353098, {"references":["Rupp, H. 1980. Beitrage zur Systematik, Verbreitung und Okologie athiopischer Nagetiere. Ergebnisse mehrerer Forschungsreisen. Saugetierkundliche Mitteilungen, 28 (2): 81 - 123.","Yalden, D. W., M. J. Largen, and D. Kock. 1976. Catalogue of the mammals of Ethiopia. 2. Insectivora and Rodentia. Monitore Zoologico Italiano, Supplemento 8 (1): 1 - 118.","Osgood, W. H. 1936. New and imperfectly known small mammals from Africa. Field Museum of Natural History, Zoological Series, 20: 217 - 256.","Allen, G. M. 1939. A checklist of African mammals. Bulletin of the Museum of Comparative Zoology at Harvard College, 83: 1 - 763.","Hollister, N. 1919. East African mammals in the United States National Museum. Part II. Rodentia, Lagomorpha, and Tubulidentata. Bulletin of the United States National Museum, 99 (2): 1 - 184."]}

Tachyoryctes ruddi Thomas, 1909. Ann. Mag. Nat. Hist., ser. 8, 4:547. TYPE LOCALITY: Kenya, Mt. Elgon, Kirui, 6000 ft. DISTRIBUTION: SW Kenya (vicinity of Mt. Elgon) and SE Uganda. SYNONYMS: badius. COMMENTS: Hollister (1919) commented on pelage traits., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 687, DOI: 10.5281/zenodo.7353098, {"references":["Hollister, N. 1919. East African mammals in the United States National Museum. Part II. Rodentia, Lagomorpha, and Tubulidentata. Bulletin of the United States National Museum, 99 (2): 1 - 184."]}

Tachyoryctes ruandae Lönnberg and Gyldenstolpe, 1925. Ark. Zool., 17B, no. 5:6. TYPE LOCALITY: Rwanda, Mt. Muhavura. DISTRIBUTION: E Zaire (Kivu), Rwanda, and Burundi. COMMENTS: See Elbl et al. (1966) and Rahm (1967) for distributional and ecological information. Stomach morphology was described by Rahm (1976) and chromosomal data was reported by Matthey (1967)., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 686, DOI: 10.5281/zenodo.7353098, {"references":["Elbl, A., U. Rahm, and G. Mathys. 1966. Les mammiferes et leurs tiques dans La Foret du Ruggege (Republique Rwandaise). Acta Tropica, 23: 223 - 263.","Rahm, U. 1967. Les Murides des environs du Lac Kivu et des regions voisines (Afrique Centrale) et leur ecologie. Revue Suisse de Zoologie, 74: 439 - 519.","Rahm, U. 1976. Zur Morphologie des Magens von Tachyoryctes splendens Ruppell, 1835 (Rodentia, Rhizomyidae). Saugetierkundliche Mitteilungen, 24: 148 - 150."]}

Tachyoryctes daemon Thomas, 1909. Ann. Mag. Nat. Hist., ser. 8, 4:545. TYPE LOCALITY: N Tanzania, Mt Kilimanjaro, 5000 ft. DISTRIBUTION: Recorded from N Tanzania (Mt Kilimanjaro, Mt Meru and other highlands between Kilimanjaro and Lake Victoria and between the lake and Rwanda); limits unknown. COMMENTS: Records are from Hollister (1919) and Swynnerton and Hayman (1951), who also listed daemon as a species., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 686, DOI: 10.5281/zenodo.7353098, {"references":["Hollister, N. 1919. East African mammals in the United States National Museum. Part II. Rodentia, Lagomorpha, and Tubulidentata. Bulletin of the United States National Museum, 99 (2): 1 - 184.","Swynnerton, G. H., and R. W. Hayman. 1951. A checklist of the land mammals of the Tanganyika Territory and the Zanzibar Protectorate. Journal of the East African Natural History Society, 20 (6): 274 - 392."]}

Tachyoryctes macrocephalus Riippell, 1842. Mus. Senckenberg., 3:97. TYPE LOCALITY: Ethiopia, Shoa. DISTRIBUTION: Ethiopia; endemic to high southern plateau (Rupp, 1980). SYNONYMS: hecki. COMMENTS: Inhabitant of Afro-alpine moorland and grassland, which it shares with the other Ethiopian endemics Stenocephalemys albocaudata, Lophuromys melanonyx, and Arvicanthis blicki (Yalden, 1988). Tachyoryctes splendens ranges from below 1000 m to the high moorland (4000 m) where it occurs together with T. macrocephalus (Rupp, 1980; Yalden et al., 1976). Yalden (1975) provided ecological observations for T. macrocephalus and morphological contrasts between it and T. splendens. See Yalden (1985, Mammalian Species, 237)., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 686, DOI: 10.5281/zenodo.7353098, {"references":["Rupp, H. 1980. Beitrage zur Systematik, Verbreitung und Okologie athiopischer Nagetiere. Ergebnisse mehrerer Forschungsreisen. Saugetierkundliche Mitteilungen, 28 (2): 81 - 123.","Yalden, D. W. 1988. Small mammals of the Bale Mountains, Ethiopia. African Journal of Ecology, 26: 281 - 294.","Yalden, D. W., M. J. Largen, and D. Kock. 1976. Catalogue of the mammals of Ethiopia. 2. Insectivora and Rodentia. Monitore Zoologico Italiano, Supplemento 8 (1): 1 - 118.","Yalden, D. W. 1975. Some observations on the giant mole-rat Tachyoryctes macrocephalus (Ruppell, 1842) (Mammalia, Rhizomyidae) of Ethiopia. Monitore Zoologico Italiano, n. s., Supplemento VI, 15: 275 - 303.","Yalden, D. W. 1985. Tachyoryctes macrocephalus. Mammalian Species, 237: 1 - 3."]}

Tachyoryctes spalacinus Thomas, 1909. Ann. Mag. Nat. Hist., ser. 8, 4:547. TYPE LOCALITY: Kenya, Embi, near Mt. Kenya, 5400 ft. DISTRIBUTION: Recorded from the plains in vicinity of Mt. Kenya (Hollister, 1919)., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 687, DOI: 10.5281/zenodo.7353098, {"references":["Hollister, N. 1919. East African mammals in the United States National Museum. Part II. Rodentia, Lagomorpha, and Tubulidentata. Bulletin of the United States National Museum, 99 (2): 1 - 184."]}

Tachyoryctes annectens Thomas, 1891. Ann. Mag. Nat. Hist., ser. 6, 7:304. TYPE LOCALITY: Kenya, Mianzini, E of Lake Naivasha (Hollister, 1919). DISTRIBUTION: Known only from vicinity of type locality. COMMENTS: Hollister (1919) commented on the distinctive large size of the holotype., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 686, DOI: 10.5281/zenodo.7353098, {"references":["Hollister, N. 1919. East African mammals in the United States National Museum. Part II. Rodentia, Lagomorpha, and Tubulidentata. Bulletin of the United States National Museum, 99 (2): 1 - 184."]}

Tachyoryctes rex Heller, 1910. Smithson. Mise. Coll., 56:4. TYPE LOCALITY: Kenya, W slopes of Mt. Kenya, 10,000 ft. DISTRIBUTION: Recorded only from 9000 to 10,700 ft on slopes of Mt. Kenya (Hollister, 1919). COMMENTS: A large-bodied and distinctive species (Hollister, 1919)., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 686, DOI: 10.5281/zenodo.7353098, {"references":["Hollister, N. 1919. East African mammals in the United States National Museum. Part II. Rodentia, Lagomorpha, and Tubulidentata. Bulletin of the United States National Museum, 99 (2): 1 - 184."]}

Tachyoryctes naivashae Thomas, 1909. Ann. Mag. Nat. Hist., ser. 8, 4:547. TYPE LOCALITY: Kenya, Lake Naivasha, 6350 ft. DISTRIBUTION: Kenya; recorded from W and S of Lake Naivasha (Hollister, 1919). COMMENTS: Considered by Thomas (19090:547) to be the smallest of the East African Tachyoryctes and occurring "quite close" to the two largest (annectens and storeyi)., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 686, DOI: 10.5281/zenodo.7353098, {"references":["Hollister, N. 1919. East African mammals in the United States National Museum. Part II. Rodentia, Lagomorpha, and Tubulidentata. Bulletin of the United States National Museum, 99 (2): 1 - 184."]}

Tachyoryctes Rüppell, 1835. Neue wirbelth. Fauna Abyssin. Gehörig., Säugeth., 1:35, footnote. TYPE SPECIES: Bathyergus splendens Rüppell, 1835. SYNONYMS: Chrysomys. COMMENTS: Hollister (1919:40) listed eight species of Tachyoryctes, noting that "all have constant characters of differentiation, and intergradation between any two of them is not indicated by this material," and speculated that the "numerous forms will doubtlessly be connected by complete chains of intergrades and the final monographer of the genus will be obliged to reduce many of the named forms to the rank of subspecies." Allen (1939) and Ellerman (1941) listed 14 species of Tachyoryctes, but these were reduced to T. macrocephalus and T. splendens by Misonne (1974) who was followed by Corbet and Hill (1991). Of the twenty forms described, Rahm (1980) considered about 16 of them to be valid subspecies of T. splendens. This change from 14 to 2 species was not based on careful analyses of morphological variation characterizing the named forms. Aside from Bekele's (1986) inconclusive univariate analyses of craniometric data from samples of Tachyoryctes, no assessment of morphological variation in the genus is available in context of a systematic revision. Until such a study provides documentation and definition of specific limits and their geographic distributions, we return to a modifed treatment of the arrangement by Allen (1939) and Ellerman (1941), which reflects the diagnostic information now available., Published as part of Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, pp. 501-755 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on pages 685-686, DOI: 10.5281/zenodo.7353098, {"references":["Hollister, N. 1919. East African mammals in the United States National Museum. Part II. Rodentia, Lagomorpha, and Tubulidentata. Bulletin of the United States National Museum, 99 (2): 1 - 184.","Allen, G. M. 1939. A checklist of African mammals. Bulletin of the Museum of Comparative Zoology at Harvard College, 83: 1 - 763.","Ellerman, J. R. 1941. The families and genera of living rodents. Vol. II. Family Muridae. British Museum (Natural History), London, 690 pp.","Misonne, X. 1974. Order Rodentia. Part 6. Pp. 1 - 39, in The mammals of Africa: An identification manual (J. Meester and H. W. Setzer, eds.). [issued 10 Sep 1974]. Smithsonian Institution Press, Washington, D. C., not continuously paginated.","Corbet, G. B., and J. E. Hill. 1991. A world list of mammalian species. Third ed. British Museum (Natural History) Publications, London, 243 pp.","Rahm, U. 1980. Die afrikanische Wurzelratte, Tachyoryctes. Die Neue Brehm-Bucherei, 528: 1 - 60.","Bekele, A. 1986. The status of some mole-rats of the genus Tachyoryctes (Rodentia: Rhizomyidae) based upon craniometric studies. Revue de Zoologie Africaine, 99: 411 - 417."]}

The effect of flooding on the behaviour of most mammals has not been studied, even though in tropical areas there are well delineated wet and dry seasons which produce flood conditions on a regular basis. Fossorial mammals can be expected to be particularly vulnerable to flooding because of the absolute dependence on a sub-surface existence and poor climbing ability. Behaviour of the East-African mole-rat, Tachyoryctes splendens, was studied under flood conditions and compared with published field work conducted under non-flood conditions. Four completely excavated burrow systems were obviously abbreviated (2–9 m in length), although the nest area did not appear to be affected. Live-trapped animals released on the surface travelled as far as 80 m before attempting to dig; surface speed was generally slow (7 m/min). Animals generally (83% of the trials) excavated towards the increase in slope on the study area; total digging time before closure of the tunnel ranged from 7–49 min. In swimming trials, animals were not hesitant to enter water but swimming endurance was short (range 115-550s). Flooding may be a very disruptive but not an entirely negative aspect of the biology of Tachyoryctes. Dispersal may be instigated and even assisted by providing surface routes over edaphic barriers and moist soils which are readily workable.

A new genus and species, Nakalimys lavocati, is described from the Nakali locality, Kenya, of about 10 Ma. This muroid rodent is assigned to the Rhizomyidae and is most similar to Kanisamys indicus from the Miocene of Pakistan, with which it was originally considered congeneric. Nakalimys, with other rodents and vertebrates, points to interchange between eastern Africa and southern Asia earlier than 10 Ma, before a more recent period of strong faunal similarity at about the beginning of the Pliocene. Nakalimys possesses many primitive characters, but was not directly ancestral to fossil and extant Tachyoryctes of Africa.