Phylogeny and evolutionary history of the Aplodontoidea (Mammalia: Rodentia)

Athough over a hundred species of fossil aplodontoids have been described since the extant species, Aplodontia rufa (the mountain beaver), was first described by Rafinesque in 1817, a thorough survey of the relationships among all the species in this clade has not been undertaken since McGrew's study in 1941. Here, a complete phylogenetic analysis of all published species of aplodontoids is used to reconstruct the evolutionary relationships within the clade, and to present an updated classification of the Aplodontoidea. Several of the traditionally recognized subfamilies are found to be paraphyletic, namely the Prosciurinae, the Allomyinae, and the Meniscomyinae. Others, however, including the Aplodontinae and the Mylagaulidae, appear to be monophyletic. These latter two taxa, which include all of the hypsodont members of the aplodontoid clade, seem to be sister taxa. The history of the aplodontoid clade shows several episodes of rapid diversification in the Early Oligocene, the Late Oligocene, and the Early to Middle Miocene. The Ansomyinae and Aplodontinae show comparatively low speciation rates. The patterns of change in morphology and evolutionary rates suggest a need for a more detailed study of the causes of diversification, extinction, and ecological change in this lineage.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153 , 769–838.     

Lung morphology in rodents (Mammalia, Rodentia) and its implications for systematics

A new nomenclature of the lung lobes and of the bronchial tree is presented, with which the lungs in 40 species of 11 rodent families are described. Whole, fixed lungs and silicone casts of the bronchial tree are tested for 23 characters, based on the distribution of lung lobes, the number and geometry of first order bronchi, the pulmonary blood supply, and lung symmetry. Ten lung morphotypes are recognized, seven of them representing one or more families: Castor type (Castoridae), Cryptomys type (Bathyergidae), Ctenodactylus type (Ctenodactylidae), Eliomys type (Gliridae), Myocastor type (Myocastoridae), Octodon type (Octodontidae and Echimyidae) and Rattus type (Sciuridae, Muridae pt. and Dipodidae). The Hydromys type is found only in Hydromys chrysogaster (Muridae), while Galea type A and B both appear in Galea musteloides (Caviidae). The data are phylogenetically analyzed by the program PAUP 4.0 using as outgroup Lagomorpha or Insectivora. On the species level, there are no well-resolved cladograms. On the family level, the cladograms do not contradict traditional rodent systematics with one exception: the Caviidae do not fall within Caviomorpha or even within the Hystricomorpha, but form a sister group to Dipodidae (Myomorpha). This appears to be a result of convergence. The lungs of Gliridae are more similar to those of Muridae than to those of Sciuridae. Included in the ingroup, Oryctolagus (Lagomorpha) forms a clade with Caviidae + Dipodidae. Thus, the "Glires hypothesis" is neither supported nor refuted.     

Higher-level systematics of rodents (Mammalia,Rodentia): Evidence from the mitochondrial 12S rRNA gene

Phylogenetic relationships among major rodent superfamilies traditionally have been difficult to establish because of the apparent high level of convergence and parallelism seen among morphological characters and/or rapid differentiation of rodent groups in the Paleocene/Eocene. Nucleotide sequence data from the mitochondrial 12S rRNA gene were used to clarify phylogenetic relationships among the major groups of rodents as defined by Brandt (1855) and Tullberg (1899). Based on the approximately 800 bp analyzed for the 12S rRNA gene in 59 mammalian species, including 25 of the 32 extant rodent families, the major rodent groups that could be defined as monophyletic clades were the Hystricognathi, the Muroidea, and the Geomyoidea. In addition, support for superfamilial sister-group relationships was found for Aplodontoidea with Sciuroidea and Dipodoidea with Muroidea.     

A phylogenetic appraisal of Sigmodontinae (Rodentia,Cricetidae) with emphasis on phyllotine genera: systematics and biogeography

Here, we present a comprehensive phylogenetic analysis based on nuclear and mitochondrial DNA sequences of rodents of the subfamily Sigmodontinae. The emphasis is placed on the large tribe Phyllotini; sampling includes for the first time in any molecular‐based phylogenetic analysis representatives of several genera traditionally considered to be phyllotines. Given the broad taxonomic sampling, results provide substantial improvements in our knowledge on both the structure of the sigmodontine radiation and of phyllotine phylogenetic relationships. For instance, the tribe Ichthyomyini was not recovered monophyletic. Similarly, in a novel hypothesis on the contents of the tribe Phyllotini, it is shown that unlike Galenomys, the genera Chinchillula, Neotomys and Punomys are not phyllotines. The later genera together with Andinomys, Euneomys, Irenomys and Juliomys form part of novel generic clades of mostly Andean sigmodontine rodents. More in general, results strongly suggest the occurrence of several instances of putative morphological convergence among distinct sigmodontine lineages (e.g. among now considered to be ichthyomyines; between Phyllotini and some Andean taxa; among Euneomys‐Neotomys and Reithrodon). Finally, we suggest that the historical biogeography of the sigmodontine rodents is far more complex than earlier envisioned.     

Juvenile cranial anatomy of Nimravidae (Mammalia, Carnivora): biological and phylogenetic implications

The anatomy of the spectacular sabretoothed carnivorans has been studied many times. Their behavioural and biomechanical implications are well known in adults, but not in juvenile individuals, which are poorly represented in the fossil record. This work reports on a newly discovered Hoplophoneini (Nimravidae Nimravinae) of 5–6 months of age, which represents the earliest and one of the most complete juvenile crania discovered. We discuss and compare the juvenile anatomy of Palaeogene nimravids relative to that of other mammals, especially other carnivorans including the Miocene nimravids (i.e. Barbourofelinae). We also discuss the ontogenetic development of this individual and other sabretoothed predators, which provides important data for reconstructing the biology of these extinct predators. Our study of the juvenile anatomy of the Hoplophoneini reveals an original association of basicranial features: the ectotympanic rotates away from the cranium earlier than in other mammals, which may be an additional autapomorphy distinguishing the Palaeogene Nimravidae from other Carnivora; within Palaeogene Nimravidae, at a similar ontogenetic stage, there is a major difference in development and maximum ventral extension of ossification of the caudal entotympanic; in contrast to the Miocene nimravid Barbourofelis, there is no strong relationship between the eruption of the upper canines and the development of other sabretoothed features (especially the mandibular flange) in the individual described. These results confirm the conclusions of recent studies which suggested that Palaeogene Nimravidae (Nimravinae) and Miocene Nimravidae (Barbourofelinae) are not closely related. Muscular reconstruction and biomechanical models also confirmed that juvenile individuals were probably not able to kill or hunt any prey. They may have fed on carcasses, eating muscles by using the incisors, and associated with a pulling or twisting action of neck. © 2003 The Linnean Society of London. Zoological Journal of the Linnean Society, 2003, 138 , 477–493.     

The evolution of fossoriality and the adaptive role of horns in the Mylagaulidae (Mammalia: Rodentia)

Ceratogaulus, a member of the extinct fossorial rodent clade Mylagaulidae, is the only known rodent with horns and the smallest known horned mammal. The function of the large, dorsally projecting nasal horns on this burrowing animal has been the subject of wide speculation among palaeontologists; suggested uses range from sexual combat to burrowing. Mammals have evolved adaptations for digging repeatedly; horns and other cranial appendages have also evolved numerous times. These two adaptations co-occur in mammals extremely rarely: only two fossil genera (Ceratogaulus and the xenarthran Peltephilus) and no extant mammals are both horned and fossorial. Tracing the evolution of fossoriality in aplodontoid rodents (the larger clade to which Ceratogaulus belongs) reveals that Ceratogaulus descended from ancestors who dug by head-lifting. Whereas this suggests an obvious explanation for the horns of this rodent, evidence from functional morphology, anatomy, phylogeny and geologic context indicates that the horns in Ceratogaulus were used for defence, rather than digging, and evolved to offset increased predation costs associated with spending more time foraging above ground as body size increased.     

Miocene Sanitheriidae (Suiformes, Mammalia) from Namibia and Kenya: systematic and phylogenetic implications

Sanitheres are enigmatic small suoids with bunoselenodont cheek teeth and a tendency for complication of the premolars by polycuspy and polycristy. Until a few years ago virtually nothing was known about their anterior dentition, but recent discoveries in Greece, Kenya and Namibia have thrown light on their incisor and canine morphology, and reveals among other things that the canines are highly sexually dimorphic, and the dm/1 is replaced by a p/1. Material from Kipsaraman, Kenya, collected between 1997 and 2003, consists of parts of mandibles and many isolated teeth, including elements of the deciduous dentition, a significant proportion of which are unworn. These new finds confirm the aberrant nature of the sanithere dentition within a suoid framework, and support their classification as a family separate from Suidae and Palaeochoeridae (= Old World Tayassuidae).

Résumé

Les sanithères sont de petits Suoïdes aux dents jugales bunosélénodontes avec des prémolaires qui présentent une tendance à la multiplication des cuspides et des crêtes (“polycuspidie” et la “polycristie”). Jusqu’à récemment, on ne connaissait rien sur la morphologie de leur dentition antérieure, mais des découvertes récentes réalisées en Grèce, au Kenya et en Namibie, lèvent le voile sur la morphologie de leurs incisives et de leur canine. Ainsi, il apparaît que les canines sont très dimorphes et que la dm/1 inférieure est remplacée par une p/1. Le matériel de Kipsaraman au Kenya, récolté entre 1997 et 2003, consiste en des fragments de mandibules et de nombreuses dents isolées, dont des dents déciduales, qui pour la plus grande part ne sont pas usées. Ces nouveaux fossiles confirment la nature aberrante de la dentition des sanithères au sein des Suoidea, et supporte leur classification dans une famille distincte des Suidae, et des Palaeochoeridae (= Tayassuidae de l’Ancien Monde).     

Biogeographical variation in the diet of Holarctic martens (genus Martes,Mammalia: Carnivora: Mustelidae): adaptive foraging in generalists

Aim Studies comparing feeding habits across a genus in different geographical regions or habitats can identify factors associated with adaptive feeding behaviour, linking key ecological traits between consumers and their environment. We investigated biogeographical patterns in dietary composition and trophic diversity across the genus Martes in relation to geographical range and environmental variables. We hypothesized that widely distributed opportunistic Martes species should demonstrate adaptive variations in dietary composition and trophic diversity relative to regional geographical location (e.g. latitude, elevation), environmental variation (e.g. temperature, rainfall, snow cover and primary productivity) and concomitant variation in food supply. Location Europe, Asia and North America. Methods We examined the dietary habits of martens (Martes spp.) using original data expressed as relative frequency of occurrence, and using principal components analysis to extract the main gradients in diet composition. These were then used as response variables in regression analyses, predicted from latitude or elevation. Multiple regression analyses were performed to assess the influence of food types and environmental variables on the trophic diversity index. Results A clear latitudinal gradient in dietary composition was observed. Small mammals were the primary food type, but were less abundant in the diet of martens at lower latitude and elevation. Vegetable matter and insects were consumed more frequently in southerly and/or lower‐elevation localities. Trophic diversity was lower at higher elevation, and increased with a decline in consumption of the dominant food types, i.e. rodents, fruits and insects. Trophic diversity also increased with increasing mean temperature. Main conclusions Biogeographical variations in feeding habits across the genus Martes proved to be associated with latitude, local climate (especially temperature regime) and the availability of alternative potential foods. On an extensive geographical scale, martens respond to varying food availability by adjusting their foraging strategy and thus should be considered facultative generalists. At the species level, however, different climatic variables emerged as differentially important, indicative of adaptations to local conditions. Martes species are opportunistic and flexible feeders, and thus their conservation requires informed management, mindful of how changes in environmental conditions might influence their varied food supply.     

中国森林田鼠族系统分类研究进展(啮齿目:仓鼠科:䶄亚科)

森林田鼠族（Myodini）是䶄亚科（Arvicolinae）的重要类群,广泛分布于整个全北区及东洋区部分区域,该族目前存在的分类学问题是缺乏化石标本、短时间的物种分化、有限分子样本和部分类群采样困难等综合因素影响的结果。近年中国森林田鼠族的系统分类研究成果主要有：（1）绒鼠属（Eothenomys）的采样和系统发育研究基本涵盖了全部类群,发现1新亚属和4新种,分别为川西绒鼠亚属（Ermites）和石棉绒鼠（Eothenomys shimianensis）、金阳绒鼠（E.jinyangensis）、美姑绒鼠（E.meiguensis）、螺髻山绒鼠（E.luojishanensis）,原来被普遍接受的黑腹绒鼠福建亚种（E.melanogaster colurnus）、中华绒鼠康定亚种（E.chinensis tarquinius）、西南绒鼠康定亚种（E.custos hintoni）被证实为3个独立有效种,滇绒鼠（E.eleusis）、丽江绒鼠（E.fidelis）的种级分类地位进一步得到确认;大绒鼠贡山亚种（E.miletus confinii）和黑腹绒鼠滇西亚种（E.melanogaster libonotus）实为克钦绒鼠（E.cachinus）的同物异名。（2）基于形态和分子系统发育的研究支持恢复东亚䶄属（Craseomys）的属级分类地位,同时解决了䶄属（Myodes）的非单系起源问题;研究进一步证实山西䶄（Craseomys shanseius）应为棕背䶄的山西亚种（Craseomys rufocanus shanseius）。（3）高山䶄属（Alticola）的平颅高山䶄亚属（Platycranius）分类地位受到分子系统发育研究结果质疑,该亚属的唯一物种平颅高山䶄（Alticola strelzowi）与高山䶄属指名亚属物种聚在同一枝;库蒙高山䶄（A.stracheyi）实为斯氏高山䶄（A.stoliczkanus）的同物异名。基于近年系统分类研究结果,目前中国森林田鼠族分布有5属共30种。     

Phylogeny and systematics of the Orycteropodidae (Mammalia,Tubulidentata)

The systematics of the order Tubulidentata is poorly known. Its phylogeny has never been thoroughly analysed and only a single review has ever been performed, which was over 30 years ago. This situation has hampered palaeoecological and palaeobiogeographical studies of these Neogene mammals. The present revision of the Orycteropodidae deals with the phylogeny and systematics of all African and Eurasian species over the last 20 Myr. The first comprehensive cladistic analysis of the family is presented here. The results of this analysis, based on 39 coded morphological characters, supplemented by non‐coded features taken from all over the skeleton, was used to reconstruct the phylogeny of the order Tubulidentata. Two distinct lineages within the genus Orycteropus are recognized and characterized. The new genus Amphiorycteropus is subsequently created, in order to harmonize taxonomy and phylogeny. The fossil genera Leptorycteropus and Myorycteropus are validated, bringing the number of genera in the order Tubulidentata to four. Moreover, within the family Orycteropodidae, the number of confirmed species is now 14. The outcome of this study allows us to propose a consistent palaeobiogeographical scenario for aardvarks. Finally, this revision represents the most comprehensive work on the evolutionary history of the order Tubulidentata to date, and provides a new framework for future studies. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 649–702.     

Functional morphology of the hindlimb of tupaiids (Mammalia,Scandentia) and its phylogenetic implications

In this study, the hindlimb of 12 species of tupaiids was analyzed functionally and compared to that of primates, dermopterans, and chiropterans. Many aspects of the tupaiid hindlimb vary in relation to differential substrate use. These differences include width of the ilium, shape of the acetabulum, size of the anterior inferior iliac spine, size of the greater and third trochanters, depth of the femoral condyles, shape of the patellar groove, and size of the tibial tuberosity. The hindlimb of the arboreal Ptilocercus lowii, the only ptilocercine, is better adapted for arboreal locomotion, whereas that of tupaiines is better adapted for rapid terrestrial (or scansorial) locomotion. The hindlimb of Ptilocercus seems to be habitually flexed and has more joint mobility, a condition necessary for movement on uneven, discontinuous arboreal supports. The tarsus of Ptilocercus facilitates inversion of the foot and its grasping hallux is capable of a great range of abduction. Tupaiines, on the other hand, are characterized by more extended hindlimbs and less mobility in their joints. These restricted joints limit movements more to the parasagittal plane, which increases the efficiency of locomotion on a more even and continuous surface like the ground. The hindlimb of tupaiines is adapted for powerful flexion and extension. Even the most arboreal tupaiines remain similar to terrestrial tupaiines in their hindlimb morphology, which probably reflects the terrestrial ancestry of Tupaiinae (but not Tupaiidae). Many attributes of the tupaiid hindlimb, especially those of the foot, reflect the arboreal ancestry of Tupaiidae and it is proposed that the ancestral tupaiid was arboreal like Ptilocercus. Also, compared to the hindlimb character states of tupaiines, those of Ptilocercus are more similar to those of other archontans, and it is proposed that the hindlimb features of Ptilocercus are primitive for the Tupaiidae. Hence, Ptilocercus should be considered in any phylogenetic analysis that includes Scandentia.     

Functional morphology of the forelimb of tupaiids (Mammalia, Scandentia) and its phylogenetic implications

In this study, the forelimb of 12 species of tupaiids was analyzed functionally and compared to that of other archontan mammals. Several differences that relate to differential substrate use were found in the forelimb morphology of tupaiids. These differences included shape of the scapula, length and orientation of the coracoid process, size of the lesser tuberosity, shape of the capitulum, length of the olecranon process, and shape of the radial head and central fossa. The forelimb of the arboreal Ptilocercus lowii, the only ptilocercine, is better adapted for arboreal locomotion, while that of tupaiines is better adapted for terrestrial (or scansorial) locomotion. While the forelimb of the arboreal Ptilocercus appears to be habitually flexed and exhibits more mobility in its joints, a necessity for movement on uneven, discontinuous arboreal supports, all tupaiines are characterized by more extended forelimbs and less mobility in their joints. These restricted joints limit movements more to the parasagittal plane, which increases the efficiency of locomotion on a more even and continuous surface like the ground. Even the most arboreal tupaiines remain similar to their terrestrial relatives in their forelimb morphology, which probably reflects the terrestrial ancestry of Tupaiinae (but not Tupaiidae). The forelimb of Urogale everetti is unique among tupaiines in that it exhibits adaptations for scratch-digging. Several features of the tupaiid forelimb reflect the arboreal ancestry of Tupaiidae and it is proposed that the ancestral tupaiid was arboreal like Ptilocercus. Also, compared to the forelimb character states of tupaiines, those of Ptilocercus are more similar to those of other archontans and it is proposed that the attributes of the forelimb of Ptilocercus are primitive for the Tupaiidae. Hence, Ptilocercus should be considered in any phylogenetic analysis that includes Scandentia.     

Genets and 'genet-like' taxa (Carnivora, Viverrinae): phylogenetic analysis, systematics and biogeographic implications

The subfamily Viverrinae is a taxon of uncertain systematic status. This study consists of cladistic analyses based on morphological characters of specimens belonging to the genera Genetta , Osbornictis , Poiana and Prionodon . Two levels of analysis are carried out, one concerning generic relationships (intergeneric analysis) and one dealing with the interrelationships of species within the genus Genetta (intrageneric analysis). In the first analysis, different outgroups were used in order to test the ingroup topology.
With regard to the intergeneric analysis, Osbornictis , Poiana and Prionodon , together with Genetta johnstoni , constitute a monophyletic group (including Nandinia ), which is the sister-group of a clade formed by the other species of genets. Thus, the genus Genetta is regarded as paraphyletic. Prionodon appears to be a derived taxon. The Poiana – Prionodon clade is well supported, especially by ultrastructural hair characters. The cladogram topology in the intrageneric analysis indicates an ecological transition from the rain forest genets to the savanna genets. This supports a rain forest origin of the genus Genetta , a conclusion which may be generalized to the entire study group. © 2002 The Linnean Society of London, Zoological Journal of the Linnean Society , 2002, 134 , 317–334.     

Molecular evolution of Holarctic martens (genus Martes,Mammalia: Carnivora: Mustelidae)

The Bering Land Bridge has served as a major corridor of interchange between the northern continents for many organisms. We investigated the phylogeny of all extant species of Martes (except for Martes gwatkinsi from India) to infer evolutionary relationships and characterize the extent of trans-Beringian movements. Analyses of complete sequences of the mitochondrial cytochrome b gene and partial sequences of the nuclear aldolase C gene (241bp) suggested that the genus Martes may be paraphyletic with respect to Gulo gulo. These data supported the fossil record's indication that early radiations gave rise to two subgenera (Pekania and Charronia) and that a more recent, possibly rapid, radiation gave rise to species of the third subgenus (Martes). Two colonizations of North America are evident, one by members of the subgenus Pekania and another by member of the subgenus Martes. Contrary to hypotheses based on morphological evidence, the "americana" and "caurina" subspecies groups of Martes americana are not the result of independent colonizations of North America. The phylogenetic analyses of cytochrome b data were consistent with the recognition of these subspecies groups as monophyletic clades; however, variation in the aldolase C sequences indicated that these generally parapatric groups may interbreed in a region of limited geographic overlap.     

Comparative study of the phylogenetic structure in six Apodemus species (Mammalia,Rodentia) inferred from ISSR-PCR data

The utility of the Inter Simple Sequence Repeat-Polymerase Chain Reaction (ISSR-PCR) was explored in order to determine genetic variation in six species of the genus Apodemus (A. flavicollis, A. sylvaticus, A. uralensis, A. agrarius, A. mystacinus and A. epimelas) at the individual level, population level, in separate geographic samples and in the species as a whole. Six optimized primers produced highly reproducible and polymorphic DNA markers with 98.3% polymorphic bands on a total sample of 91 individuals from 32 localities in Europe and Asia. Moreover, each primer allowed for an exact diagnosis of each of the six Apodemus species and thus provides a simple and reliable tool for the hitherto problematic discrimination of species from the subgenus Sylvaemus. Genetic distances between species ranged from 0.079, among the closely related A. flavicollis and A. sylvaticus, to 0.203 between A. mystacinus and A. agrarius. A. flavicollis, A. uralensis and A. sylvaticus display a strong population substructure. The range of genetic distances among geographic samples within last two species reaches the values obtained for closely related species. ISSR markers proved to be a simple and reliable tool for species diagnosis, as well as for estimating genetic diversity below the species level and for closely related species, but they showed questionable reliability for larger genetic distances.     

Sciuridae (Rodentia,Mammalia) from the Late Miocene of Venta del Moro (Cabriel Basin,Spain): biostratigraphical,phylogenetic and palaeoecological inferences

Abstract

Fossil squirrels are relatively abundant in Aragonian and Ramblian assemblages, but very scarce in the Late Turolian and Ruscinian of the Iberian Peninsula. Until now, the locality of Venta del Moro has yielded over 4500 micromammal dental remains, but just nine of them are sciurids. In this assemblage, we have identified the taxa Pliopetaurista pliocaenica, Heteroxerus cf. mariatheresae and Atlantoxerus cf. margaritae. This is the first co-occurrence of the genera Pliopetaurista, Heteroxerus and Atlantoxerus in the same locality, being also one of the oldest records of P. pliocaenica, the oldest record of a form that could be related to A. margaritae, and the youngest record of the genus Heteroxerus. In addition, we hypothesize about the phylogeny of Pliopetaurista in the light of recent discoveries. Finally, the presence of the genera Heteroxerus and Atlantoxerus suggests an open environment and relatively dry environmental conditions, while Pliopetaurista is purportedly a flying squirrel, dweller of forested habitats and wet climates. Based on this, we infer an open environment of grassland type, bordered by forested habitats, agreeing with the conditions supposed for Venta del Moro according to its macromammal and floral assemblages.     

Systematics and evolution of the subfamily Gerbillinae (Mammalia, Rodentia, Muridae)

Although they represent a quarter of the mammalian species, the evolutionary relationships among as well as within, the main murid lineages are still controversial. The subfamily Gerbillinae is no exception as previous studies based on morphological, karyotypical, and allozyme characters are highly incongruent. Here, we present the first molecular phylogeny for gerbils based on cytochrome b and 12S rRNA mitochondrial genes. Results are largely congruent between the two genes as well as with the concatenated data set with most of the nodes being well-supported. Based on the topologies retrieved here, we (1) propose the identification of three main clades, (2) support the split of Tatera genus into an Asian and an African group, the latter including Gerbillurus species, and (3) provide some evidence towards the inaccuracy of subgeneric divisions within both Gerbillus and Meriones. In addition, the sharp contrast between the genetic characters and morphological data sets suggest high levels of convergence, probably as a result of strong environmental constraints imposed on these rodents adapted to arid and semi-arid regions. Finally, molecular datings for the various cladogenetic events are in good agreement with the known gerbilline fossil record and support an African origin with subsequent migrations to Asia.     

A new Oligocene Ctenodactylinae (Rodentia: Mammalia) from Ulantatal (nei Mongol): new insight on the phylogenetic origins of the modern Ctenodactylidae

The four living genera of Ctenodactylidae (Rodentia) are the only survivors of a flourishing Tertiary group. In this paper, we describe a new Oligocene species from Ulantatal (Chinese Mongolia) that highlights the origins of crown ctenodactylids. This species, Helanshania deserta gen. et sp. nov. , is lophodont and displays semi‐hypsodont teeth, a dental pattern that is somewhat transitional between that of primitive Oligocene ctenodactylids and the later hypsodont genera. We perform here a cladistic assessment of the dental evidence for species produced by the successive radiations of the group. In order to get new data, to decipher homologies for the dental pattern of modern ctenodactylids, and to specify their dental replacement, we describe additional dental material of Ctenodactylus, Massoutiera, and Felovia. The phylogenetic analysis (using PAUP) considered 45 characters (mainly dental) and 31 species. The performed heuristic searches yielded 596 equally most parsimonious trees. Protataromys and Karakoromys are stem ctenodactylids and appear as the earliest offshoots of the Ctenodactylidae clade, which represents a well‐supported family rank. Within this family, the Tataromyinae appear paraphyletic, whereas the Ctenodactylinae sensu lato are a clade including the new taxon Helanshania. As such, a revision of the Tataromyinae is envisaged and a new subfamily is erected (Yindirtemyinae). Amongst the Ctenodactylinae, a tribe Ctenodactylini encompassing the crown ctenodactylines is proposed. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 531–550.