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The Eocene-Oligocene Transition (EOT) was one of the most profound climate changes in the Cenozoic era, characterized by global cooling around 34 million years ago. This time period also witnessed major faunal turnovers, such as the “Mongolian Remodeling” of Asia, characterized by the dominance of rodents and lagomorphs after the EOT. Previous studies have primarily focused on overall faunal change across the EOT. Here, we examined one genus, the earliest ctenodactylid Karakoromys, based on rich fossils from continuous sections at Ulantatal, Nei Mongol, magnetostragraphically dated to latest Eocene-Early Oligocene. Based on a systematic paleontological study of these fossils, we recognized four species of Karakoromys (Karakoromys decussus, K. arcanus, K. chelkaris, and K. conjunctus sp. nov.), indicating a relatively high diversity of the most primitive ctenodactylids during the latest Eocene-Early Oligocene (~34.9–30.8 Ma). The turnover of ctenodactylids primarily occurred during a regional aridification event around 31 Ma rather than during the EOT cooling event, suggesting that regional precipitation variation in the semi-arid area may have played a more important role than global temperature change in the evolution of early ctenodactylids.

Sayimys assarrarensisLÓPEZ-ANTOÑANZAS et SEN, 2004 H o l o t y p e. A fragmentary left maxilla with P4–M2. P a r a t y p e s. Some 18 isolated cheek teeth. Ty p e l o c a l i t y. As-Sarrar, Dam Formation, Saudi Arabia; assigned age of the site: later part of the early Miocene, 15–17 Ma. D i s c u s s i o n. This small species is similar in size to Sayimys intermedius. The As Sarrar locality is slightly older than the type locality of S. intermedius. The single reasonably preserved dp4 of S. assarrarensis shows a welldeveloped mesolophid and a slightly elongated anteroconid. Considering the large variation in dental morphology and size of large Sayimys assemblages, we consider S. assarrarensis a junior synonym of S. intermedius. More material is needed from the type localities to ascertain specific differences, if any., Published as part of Hartman, Julian, Van De Weerd, Andrew A., Bruijn, Hans De & Wessels, Wilma, 2019, An Exceptional Large Sample Of The Early Miocene Ctenodactyline Rodent Sayimys Giganteus, Specific Variation And Taxonomic Implications, pp. 359-382 in Fossil Imprint 75 (3 - 4) on page 373, DOI: 10.2478/if-2019-0023, http://zenodo.org/record/5457521

An assemblage of the early Miocene Sayimys giganteus (Ctenodactylinae, Rodentia) from its type locality Keseköy, and smaller assemblages of Yapıntı and Horlak (Anatolia, Turkey) are described. Almost all Sayimys species are known from small collections of isolated cheek teeth. The very large assemblage from Keseköy is of special interest, because it allows the study of the intra-specific variation of dental morphology: size, the morphological changes through wear and the criteria for recognition of the tooth position of molars. The results have been used to review the formally named Sayimys species and to evaluate the dental features used to define the species. The review of the early and middle Miocene succession of Sayimys in the Siwaliks (Pakistan) resulted in the resurrection of S. minor; S. baskini is considered to be a junior synonym of S. minor. S. sivalensis and S. obliquidens are nomina dubia, and restricted to their holotypes, S. hintoni n. sp. is established for mediumsized Sayimys from the Kamlial, lower Chinji and Manchar Formations and S. chinjiensis is resurrected for Sayimys from the upper Chinji and Nagri Formations. It is suggested that the middle Miocene species Sayimys intermedius and S. assarrarensis from Saudi Arabia are synonymous.

5. Desert Gundi Ctenodactylus vali French: Goundi du désert / German: Wiistengundi / Spanish: Gundi del desierto Other common names: Sahara Gundi, Thomas's Gundi Taxonomy. Cienodactylus vali Thomas, 1902, “Wadi Bey,just northwest of Bonjem” (= ¢.330 km south-east of Tripoli, Libya). This species is monotypic. Distribution. N Africa in two discrete and widely separated areas (NE Morocco & NW Algeria and NW Libya). Descriptive notes. Head-body 124-185 mm, tail 27-43 mm; weight up to 185 g. The Desert Gundi is, on average, smaller than but similar in external morphology and color to the Common Gundi (C. gundi). Despite their similarity, there are some morphological, behavioral, and communicative differences between them. The Desert Gundi has more inflated auditory bullae and proportionally longer large intestine than the Common Gundi. Fecal pellets of the Desert Gundi are shorter than those of the Common Gundi. Calls of the Desert Gundi are of higher frequency than those of the Common Gundi. Habitat. Rocky deserts including mountain slopes, edges of “hamadas” (stony desert plains), “wadis” (ephemeral riverbeds), “rift” (linear down-faulted depressions), and small mountains. The Desert Gundi can be found in semi-desert areas. Food and Feeding. The Desert Gundiis herbivorous. It lives in areas with plant cover of ¢.2%, exceptfor a few weeks every few years following rain. The Desert Gundieats, in order of preference, the crucifer Eremophyton chevallieri (Brassicaceae) and the composite Amberboa leucantha (Asteraceae), followed by grass genera Cymbopogon and Aristida (both Poaceae). Plants included in its diet have lower water content than those eaten by the Common Gundi. The Desert Gundi mainly forages at dawn and dusk when temperatures are less extreme. Breeding. Desert Gundis start breeding at 7-9 months old, and females have a vaginal closure membrane during periods of sexual inactivity. Unlike the Common Gundi, the Desert Gundiis sexually inactive most of the time, and its gestation is 60-65 days. Desert Gundis produce two litters each year under favorable conditions with up to three newborns in them (two on average), but they do not reproduce in extreme conditions and scarcity of food. Firstlitters are usually born in February-March and the second in April-May (these dates are delayed by c.2 months for individuals that live in high elevations). A prepartum estrus is suspected for the second copulation. Females are able to store spermatozoa in their genital tracts for at least two months and use them without further copulation to produce a replacement litter. Social behavior of the Desert Gundi greatly differs from that of the Common Gundi. A Desert Gundi lives alone most of the year. At the end of autumn, a female settles in a place, and several males try to join her. After a familiarization period, only one male is selected, and supernumerary males disappear. The male stays with the female during gestation, but he leaves before birth of the first litter. Neonates are precocial and born fully furred with their eyes and ears open and functional. Young remain close to their shelter, but sharing a night shelter between mother and youth is short-lived and stops well before weaning. The mother joins the young in the morning and may spend the rest of the afternoon with them. Young Desert Gundis from the first litter disperse before birth of the second litter in April-May. At the end ofJune, all individuals become erratic, and it is not until November after establishment of male-female relationships that these individuals become sedentary again. Activity patterns. Desert Gundis sunbathe, forage, rest in the shade, and groom. The Desert Gundi spends more time (50-70%) outside than the Common Gundi (50%), but during the hot season, these percentages decrease, never exceeding 15%; in June, the Desert Gundi might be inside its shelter from 11:00 h to 17:00 h, longer than for the Common Gundi. The Desert Gundi replaces sunbathing by resting in the shade at lower temperatures than the Common Gundi, perhaps because of lower water content in plants that the Desert Gundi consumes compared with those eaten by the Common Gundi. Desert Gundis emit panic calls if a predator suddenly appears or alert calls if it is seen from a safe distance. Movements, Home range and Social organization. The Desert Gundi is usually sparsely distributed, but high density may be observed under favorable conditions (up to 18 ind/ha). It is essentially solitary from June to late October. Home ranges are usually smaller (100-500 m* in the wet season and 1125 m® in the hot season) than those of the Common Gundi. Unlike Common Gundis, Desert Gundis do not establish strong or lasting social bonds. Status and Conservation. Classified as Data Deficient on The [UCN Red List. The Desert Gundi does not seem to be threatened, and decreases in densities are probably due to climatic changes. Bibliography. Aulagnier (2008d), Dieterlen (2005b), George (1974, 1978, 1981a, 1982, 2001), Gouat, J. (1985, 1986, 1989), Gouat, J. & Gouat (1984, 1987), Gouat, J. et al. (1985), Gouat, P (1991, 1992, 1993, 2013), Gouat, P & Gouat (1983, 1987), Lopez-Antonanzas & Knoll (2011), Pocock (1922), Ranck (1968), de Rouffignac et al. (1981)., Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Ctenodactylidae, pp. 288-299 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on pages 298-299, DOI: 10.5281/zenodo.6587796

1. Speke’s Gundi Pectinator spekei French: Goundi de Speke / German: Buschschwanz-Gundi / Spanish: Gundi de Speke Other common names: Bushy-tailed Gundi, Speke's Pectinator Taxonomy. Pectinator spekei Blyth, 1856, “Somali country” (= Laasqoray area, about 1040 km north-north-east of Mogadishu, Somalia. This species is monotypic. Distribution. Horn of Africa (Eritrea, Djibouti, Ethiopia, and Somalia), geographically isolated from the other gundis. Descriptive notes. Head-body 155-190 mm, tail 60-80 mm; weights up to 194 g. External characteristics of Speke’s Gundi are similar to those of other living members of the family. Dorsal pelage is sandy colored, intermixed with black or brown, and it becomes grayish white ventrally. Speke’s Gundi and the Felou Gundi (Felovia vae) have long tails used in social displays and moderately inflated auditory bullae. Speke’s Gundi has the largest pinnae of all ctenodactylids, and in contrast with other gundis, they are only partially flattened on the head. Mandible has a short angular process. Speke’s Gundi is the only living species of ctenodactylid that conserves numerous archaic dental characters present in the first ctenodactylines; e.g. it has retained the primitive dental formula of its ancestors, which includes deciduous premolars (aP*t/dP). Deciduous third premolar is generally present in maxilla but lost in mandible. Some specimens of Speke’s Gundi for which dP, have been identified are now suspected to be anterior fragments of dP,. The fourth upper and lower deciduous premolars (dP4) are replaced by fourth permanent premolars. Remaining modern species of gundis have lost the dP3 and seem to bear only deciduous premolars that are lost without being replaced in adulthood. Therefore, they show a more simplified dental formula. Cheekteeth are euhypsodont (rootless and ever-growing) in all-living ctenodactylids, except for Speke’s Gundi that has high-crowned (hypsodont) but still rooted molars. Habitat. Semi-desert rocky areas, occupying fissures in limestone cliffs. Speke’s Gundi is the only living ctenodactylid that inhabits the Horn of Africa. Food and Feeding. Speke’s Gundiis herbivorous and eats dry grass, seeds, and leaves of Cadaba rotundifolia (Capparaceae). When possible, it prefers leaves of acacia, particularly Acacia senegal (Fabaceae), which has short spines (6 mm), to those of A. seyal. When A. senegal is not available, Speke’s Gundis cope with the 65mm sharp spines of A. seyal. Breeding. Timing of reproduction of Speke’s Gundis occurs relative to habitat and geographical location. Unpublished recent field observations by P. Gouat in Djibouti suggest that Speke’s Gundis start to reproduce in August. They produce two litters/ year that are mostly singletons. Juveniles from the two litters are seen in late October to early November. As is the case with all species of gundis, newborn Speke’s Gundis are precocial and grow relatively fast; they attain adult size in ¢.6 months. Activity patterns. Similarly to the other gundis, Speke’s Gundis mainly sunbathe, forage, rest in the shade, and groom. Peak activity occurs 0-3 hours after dawn when temperatures are 23-29°C. As temperatures rise, Speke’s Gundis find refuge in shelters; they reappear outside in late afternoon. Movements, Home range and Social organization. Speke’s Gundis are social and live in comparatively dense colonies up to 237 ind/ha. These colonies contain close and extended family groups. Home ranges are 1500-2000 m?, Status and Conservation. Classified as Least Concern on The IUCN Red List. Currently, Speke’s Gundis do not face any significant conservation threats. Bibliography. Coetzee & Grubb (2008), Dieterlen (2005b), George (1974, 1978, 1981a, 2001), Gouat (2013, 2015), Lépez-Antonanzas & Knoll (2011)., Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Ctenodactylidae, pp. 288-299 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on page 296, DOI: 10.5281/zenodo.6587796

3. Felou Gundi Felovia vae French: Goundi de Félou / German: Senegal-Gundi / Spanish: Gundi de Félou Other common names: Senegal Gundi Taxonomy. Massoutiera (Felovia) wvae Lataste, 1886, “Felou Senegalis” (= ¢.410 km north-west of Bamako, Mali). This species is monotypic. Distribution. C Mauritania, W Mali, and E Senegal, geographically isolated from the other gundis. Descriptive notes. Head-body 169-190 mm, tail 67-80 mm; weight up to 188 g. External characteristics of Felou Gundi are generally similar to other gundi species. It can be distinguished from all living ctenodactylids by strongly grooved upper incisors and less inflated auditory bullae. Pinnae resemble those of Speke’s Gundi (Pectinator spekei), but the Felou Gundi has a shorter, flattened head, bordered with hairs. The Felou Gundi has a furry tail, longer than tails of other gundi species except Speke’s Gundi. Both species differ from the other gundi species by having short angular processes in their mandibles. Habitat. Rocky areas where rainfall is relatively high (more than 600 mm/year) for a semi-desert habitat but also areas with scarce and seasonal rains. The Felou Gundi is found in river canyons, fissures of sandstone hills, and among boulders and cliffs. Food and Feeding. The Felou Gundiis herbivorous. It lives in less hostile areas than the Mzab Gundi (Massoutiera mzabi) and the Desert Gundi (Ctenodactylus vali). Thus, the Felou Gundi experiences seasons of relatively high abundance of food, followed by months of scarcity. It feeds on leaves of the leguminous shrub Tephrosia mossiensis (Fabaceae), dropped stalks offig trees, leaves, dry grass, and seeds in the dry season. The Felou Gundi is the only gundi species that has been seen drinking from oasis and water ponds in Mauritania. Breeding. Reproduction of the Felou Gundi is poorly known. Births have been suspected to occur in mid-December—January. All knownlitters are singletons. Activity patterns. Similarly to the other gundis, Felou Gundis mainly sunbathe, forage, rest in the shade, and groom. A Felou Gundi was seen sunbathing in a rock with a surface temperature of 38°C. The Felou Gundi and the Common Gundi may tolerate higher temperatures than other gundi species, which may be related to availabilities of plants with higher water content. Movements, Home range and Social organization. The Felou Gundi lives in small family groups, sharing a territory of ¢.3000 m* with other nearby family groups. It lives in relatively dense colonies depending on the area (up to 25 ind/ha in Mali but much less in central Mauritania). Felou Gundis live in permanent shelters; they still occur at the same place where Lataste discovered them in 1885. Due to their flat and compressible thorax, all gundis are capable of flattening into narrow crevices of ¢.25 mm when threatened (even narrower for the Felou Gundi and Speke’s Gundi). Felou Gundis are noisy and emit alert calls that can go on for one-half hour. Status and Conservation. Classified as Data Deficient on The IUCN Red List. A study by C. G. Vale and colleagues in 2012 concluded that the Felou Gundi was not threatened. Drought and general desertification and deforestation of the Sahel may threaten the Felou Gundi, mainly because ofits link to water availability. Felou Gundis may have been affected by past droughts (e.g. 1970s), and continued decrease in habitat quality is expected in the future because of climate change. Assessment of populations of Felou Gundis projected for the next two decades, taking into account probability of more frequent or severe droughts within its distribution,still suggests populations above the IUCN threshold given for threatened taxa. Bibliography. Aulagnier (2008b), Dieterlen (2005b), George (1974, 1978, 1981a, 2001), Gouat (2013), Granjon & Duplantier (2011), Honigs & Greven (2003), Lopez-Antonanzas & Knoll (2011), Padial & Telleria (2009), Vale et al. (2012).

3. Felou Gundi Felovia vae French: Goundi de Félou / German: Senegal-Gundi / Spanish: Gundi de Félou Other common names: Senegal Gundi Taxonomy. Massoutiera (Felovia) wvae Lataste, 1886, “Felou Senegalis” (= ¢.410 km north-west of Bamako, Mali). This species is monotypic. Distribution. C Mauritania, W Mali, and E Senegal, geographically isolated from the other gundis. Descriptive notes. Head-body 169-190 mm, tail 67-80 mm; weight up to 188 g. External characteristics of Felou Gundi are generally similar to other gundi species. It can be distinguished from all living ctenodactylids by strongly grooved upper incisors and less inflated auditory bullae. Pinnae resemble those of Speke’s Gundi (Pectinator spekei), but the Felou Gundi has a shorter, flattened head, bordered with hairs. The Felou Gundi has a furry tail, longer than tails of other gundi species except Speke’s Gundi. Both species differ from the other gundi species by having short angular processes in their mandibles. Habitat. Rocky areas where rainfall is relatively high (more than 600 mm/year) for a semi-desert habitat but also areas with scarce and seasonal rains. The Felou Gundi is found in river canyons, fissures of sandstone hills, and among boulders and cliffs. Food and Feeding. The Felou Gundiis herbivorous. It lives in less hostile areas than the Mzab Gundi (Massoutiera mzabi) and the Desert Gundi (Ctenodactylus vali). Thus, the Felou Gundi experiences seasons of relatively high abundance of food, followed by months of scarcity. It feeds on leaves of the leguminous shrub Tephrosia mossiensis (Fabaceae), dropped stalks offig trees, leaves, dry grass, and seeds in the dry season. The Felou Gundi is the only gundi species that has been seen drinking from oasis and water ponds in Mauritania. Breeding. Reproduction of the Felou Gundi is poorly known. Births have been suspected to occur in mid-December—January. All knownlitters are singletons. Activity patterns. Similarly to the other gundis, Felou Gundis mainly sunbathe, forage, rest in the shade, and groom. A Felou Gundi was seen sunbathing in a rock with a surface temperature of 38°C. The Felou Gundi and the Common Gundi may tolerate higher temperatures than other gundi species, which may be related to availabilities of plants with higher water content. Movements, Home range and Social organization. The Felou Gundi lives in small family groups, sharing a territory of ¢.3000 m* with other nearby family groups. It lives in relatively dense colonies depending on the area (up to 25 ind/ha in Mali but much less in central Mauritania). Felou Gundis live in permanent shelters; they still occur at the same place where Lataste discovered them in 1885. Due to their flat and compressible thorax, all gundis are capable of flattening into narrow crevices of ¢.25 mm when threatened (even narrower for the Felou Gundi and Speke’s Gundi). Felou Gundis are noisy and emit alert calls that can go on for one-half hour. Status and Conservation. Classified as Data Deficient on The IUCN Red List. A study by C. G. Vale and colleagues in 2012 concluded that the Felou Gundi was not threatened. Drought and general desertification and deforestation of the Sahel may threaten the Felou Gundi, mainly because ofits link to water availability. Felou Gundis may have been affected by past droughts (e.g. 1970s), and continued decrease in habitat quality is expected in the future because of climate change. Assessment of populations of Felou Gundis projected for the next two decades, taking into account probability of more frequent or severe droughts within its distribution,still suggests populations above the IUCN threshold given for threatened taxa. Bibliography. Aulagnier (2008b), Dieterlen (2005b), George (1974, 1978, 1981a, 2001), Gouat (2013), Granjon & Duplantier (2011), Honigs & Greven (2003), Lopez-Antonanzas & Knoll (2011), Padial & Telleria (2009), Vale et al. (2012)., Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Ctenodactylidae, pp. 288-299 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on pages 297-298, DOI: 10.5281/zenodo.6587796

Don E. Wilson, Thomas E. Lacher, Jr, Russell A. Mittermeier (2016): Ctenodactylidae. In: Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I. Barcelona: Lynx Edicions: 288-299, ISBN: 978-84-941892-3-4, DOI: http://doi.org/10.5281/zenodo.6587796

2. Mzab Gundi Massoutiera mzabi French: Goundi du Mzab / German: Langhaar-Gundi / Spanish: Gundi de Mzab Taxonomy. Ctenodactylus mzabi Lataste, 1881, “Sahara algérien: Gardaia (Mzab)” (= Ghardaia, c.480 km south of Algiers, Algeria). Allocated by F. Lataste to the new genus Massoutiera in 1885. Monotypic. Distribution. Discontinuous distribution in C & SE Algeria, E Mali, W Niger, and NW Chad and possibly in SW Libya. Descriptive notes. Head-body 125-210 mm, tail 33-85 mm; weight up to 234 g. Similar to other species of gundis, the Mzab Gundi has a thick and compact body with dense pelage, short and flattened ears, long black vibrissae, big distally positioned eyes, short limbs, and tetradactyle feet with comb-like bristles in the two inner digits of the hindfeet. Pelage of the Mzab Gundi is highly variable, usually cream to reddish brown dorsally and paler ventrally. In basaltic areas, the Mzab Gundi tends to be uniformly chocolate brown. The Mzab Gundi differs from other species gundi by its hugely expanded auditory bullae (among the most expanded of any desert rodent). Its furry tail is intermediate in size, longer than in the Common Gundi (Ctenodactylus gundi) and the Desert Gundi (C. vali) but shorter than in Speke’s Gundi (Pectinator speket). It is mobile and can be used to balance. The Mzab Gundi also has the longest large intestine of all gundi species. Skull and mandible are quite similar in all species of Ctenodactylidae, but the angular process is most developed in the Common Gundi, the Desert Gundi, and the Mzab Gundi compared with the Felou Gundi (Felovia vae) and Speke’s Gundis. The Mzab Gundi has a simplified dental formula; cheekteeth are euhypsodont and covered by cementum. Upper incisors are faintly grooved, or not at all, and morphology of cheekteeth is quite different compared with other species of gundis. Habitat. Rocky mountains and edges of “hamadas” (stony desert plains) in desert and semi-desert areas. The Mzab Gundilives under a variety of climatic conditions, and along with the Desert Gundi,it can be found in areas with extremely high mean temperatures and low rainfall (less than 20 mm of rain/year). Breeding. Mzab Gundis breed when they are 7-9 months old. Females have vaginal closure membranes during periods of sexual inactivity and distinct periods of estrus. Gestation is 60-65 days. Similar to Common Gundis and Desert Gundis, Mzab Gundis produce two litters/year under favorable conditions, with up to three newborns in each (two on average), but they do not reproduce under extreme conditions and food scarcity. In the Mzab region, first litters are usually born in January-March and second litters in April-May. Female Mzab gundis are sedentary and territorial and occupy the same area of 1000-2000 m* throughout the year. In autumn (September— December), a male joins a female in her territory and stays with her until the birth of their first litter and, if food is available, until the birth of their second litter, at the latest until the beginning of summer (June). During this period, they cooperate to defend their territory. After birth and during the first month oflife, the male hardly ever interacts with his offspring, but he may watch them from a distance. The mother carries her young in her mouth from one shelter to another, feeds them, and spends at least part of the night with them. Young males stay with their mothers until the beginning of summer, but females stay longer and even, whenever possible, establish themselves in a home range near their mothers. Food and Feeding. The Mzab Gundi is herbivorous. In winter (November—March), it forages all the time, but in summer (April-September), it forages only during the coolest times of the day. In summer, it becomes partly nocturnal, foraging before sunrise until 10:00 h and then again in late afternoon until after sunset. The Mzab Gundi seems to be less selective than the Common Gundi, and although it shows preference for crucifers and composites, it eats the most abundant plants available. When there is a choice, the Mzab Gundi favors fresh leaves to stalks and frequently eats flower heads. It prefers the cruciferous purple-flowered Moricandia arvensis (Brassicaceae), leaves of the herbaceous Reseda sp. (Resedaceae), and flower heads of the yellow Launea sp. (Asteraceae); it also eats Stipa retorta (Poaceae). Survival of the Mzab Gundi in hostile environments of the Sahara is possible because ofits behavioral patterns and access to plants with water content in excess of 50% in the early hours of the morning. Activity patterns. Similarly to the other gundis, Mzab Gundis mainly sunbathe, forage, rest in the shade, and groom. The Mzab Gundiis the only known gundi that remains active after nightfall but only during the hot season. It has the most effective behavioral adaptations to temperature variation of all gundi species, dissipating body heat and conserving water. The Mzab Gundi avoids direct sun exposure at temperatures of 20° or more, and it is typical to see it lying on cooler ledges, allowing it to stay outside longer. During eight hours and 20 minutes of observation when temperatures ranged from 18°C at dawn and 35°C by midday, a Mzab Gundi spent 40% of its time dashing about, 12% sunbathing, 6% foraging, and 42% resting in the shade. Movements, Home range and Social organization. Mzab Gundis live at low densities (0-3-3-2 ind/ha) and shelter in small and disperse family groups. They can travel long distances before making contact with other groups. Females are sedentary and territorial; each adult female lives in a territory of 1000-2000 m* throughout the year and uses many temporary shelters instead of a few permanent ones. In autumn (September—-December), a male joins a female in her territory to reproduce, and he stays with her at most until the beginning ofJune, depending on food availability. At this time, young males of both litters also disperse; therefore, solitary Mzab Gundis are common in summer. During cohabitation, an adult male and female cooperate to defend their territory from conspecific intruders. The Mzab Gundi is the mostsilent ofall gundis, but young and adults emit alarm calls when a predator is detected. Status and Conservation. Classified as Least Concern on The IUCN Red List. The Mzab Gundi does not face any serious conservation threats. It is known from the prehistoric (c. 7000 Bc) site of Ti-n-Torha (Tadrart Acacus, Libya). Bibliography. Aulagnier (2008a), Dieterlen (2005b), Gautier (1987), Gautier & van Neer (1982), George (1974, 1978, 1981a, 1988), Gouat (1991, 1993, 2013), Gouat et al. (1984), Lataste (1885), Lopez-Antonanzas & Knoll (2010, 2011), Nutt (2008), Pocock (1922), Ranck (1968)., Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Ctenodactylidae, pp. 288-299 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on page 297, DOI: 10.5281/zenodo.6587796

Don E. Wilson, Thomas E. Lacher, Jr, Russell A. Mittermeier (2016): Ctenodactylidae. In: Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I. Barcelona: Lynx Edicions: 288-299, ISBN: 978-84-941892-3-4, DOI: http://doi.org/10.5281/zenodo.6587796

Family CTENODACTYLIDAE (GUNDIS) • Medium-sized rodents with short legs, short tails, flat ears, big eyes, and long whiskers. • 16-30 cm. • Palearctic and Afrotropical regions. • Essentially desert or semi-desert terrains. • 4 genera, 5 species, 5 taxa. • No species threatened; none Extinct since 1600., Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Ctenodactylidae, pp. 288-299 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on page 288, DOI: 10.5281/zenodo.6587796

Vianey-Liaud, Monique, Rodrigues, Helder Gomes, Marivaux, Laurent (2010): A new Oligocene Ctenodactylinae (Rodentia: Mammalia) from Ulantatal (nei Mongol): new insight on the phylogenetic origins of the modern Ctenodactylidae. Zoological Journal of the Linnean Society 160 (3): 531-550, DOI: 10.1111/j.1096-3642.2010.00615.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2010.00615.x

CTENODACTYLINAE HINTON, 1933 Type genus: Ctenodactylus, Gray, 1828. Included genera: Sayimys, Prosayimys, Metasayimys, Africanomys, Sardomys, Pireddamys, Irhoudia, Pellegrinia, Pectinator, Massouteria, Felovia, Helanshania gen. nov. The genus Testouromys was erected by Robinson & Black (1974) for one complete m3, one broken m1, and one eroded M1, from a Tunisian Miocene locality (Testour). The m3 has a pattern close to that of some species of Sayimys, with open – V shaped mesosynclinid and metasynclinid, like in Sayimys baskini (López-Antoñanza & Sen, 2004). For that reason, Testouromys could be synonymized with Sayimys. Akzharomys, erected by Shevyreva (1994) on the basis of a few teeth from the lower Miocene Akhzarian Formation, has not been further used. From its trilobate pattern, the lack of a trigonoid structure on the m3, and the M2 with a sinus relatively longer than in molars of Helanshania or Prosayimys, as in the species of Sayimys, this genus is possibly a junior synonym of Sayimys. Geological range and geographical distribution: Late early to early late Oligocene in Central Asia (Inner Mongolia), from early to late Miocene (North China, Mongolia, Kazakhstan, North India, Pakistan, Greece, Turkey, Libya, Morocco, Sardinia), Pleistocene (Sicily), Recent (arid zones of North Africa, from Morocco to Libya, Saharan Africa from Mauritania, Algeria, Chad to Ethiopia and Somalia). Emended differential diagnosis Ctenodactylinae differ from Tataromyinae in: Skull and mandible: ‘reduction’ of the temporal masticatory apparatus, which includes a small temporal fossa and a weak temporal crest, low condyle and low to absent coronoid process; sciurognathous mandible showing a great development of the masseter -pterygoid masticatory apparatus, with a single horizontal heavy masseteric crest. Cheek teeth: reduction of the premolars (in size and eventually in number) compared to the Tataromyinae; dental formula 1/1, 2-1/1-0, 3/3. DP4/dp4 may be retained a more or less long time; then P4/p4 may be lost early in life. Cheek teeth from unilaterally hypsodont to hypsodont; cementum occasionally filling the sinus (sinusid) and synclines (synclinids). Entolophid displaced forward, to the middle of the lower molars; possible reduction of the mesosynclinid; anterocone absent on the upper cheek teeth; hypocone as strong as the protocone; reduction of the anterior and posterior synclines on the upper molars; tendency to produce a bilobate pattern, first on upper, then on lower, molars., Published as part of Vianey-Liaud, Monique, Rodrigues, Helder Gomes & Marivaux, Laurent, 2010, A new Oligocene Ctenodactylinae (Rodentia: Mammalia) from Ulantatal (nei Mongol): new insight on the phylogenetic origins of the modern Ctenodactylidae, pp. 531-550 in Zoological Journal of the Linnean Society 160 (3) on page 533, DOI: 10.1111/j.1096-3642.2010.00615.x, http://zenodo.org/record/5493899, {"references":["Hinton MAC. 1933. Diagnoses of new Genera and Species of Rodents from the Indian Tertiary deposits. Annales and Magasine of Natural History 10 (12): 620 - 622.","Robinson P, Black CC. 1974. Vertebrate faunas from the Neogene of Tunisia. Annals of the Geological Survey of Egypt IV: 319 - 332.","Lopez-Antonanza R, Sen S. 2004. Ctenodactylids from the lower and middle Miocene of Saudi Arabia. Paleontology 47: 1477 - 1494.","Shevyreva N. 1994. A new neogene Ctenodactyloidea (Rodentia, Mammalia) from the Zaisan depression (Eastern Kazakhstan). Paleontologicheskii Zhurnal 28: 126 - 131."]}

Prodistylomys lii, n. sp. Figures 6–7, table 1 HOLOTYPE: IVPP V16015.1, right fragmentary mandible with broken i2, and m1–m3. REFERRED MATERIAL: IVPP V 16015.2, right M3; V 16015.3, right p4. STRATIGRAPHIC AND GEOGRAPHIC PROVENANCE: Suosuoquan Formation of Chibaerwoyi, Xinjiang. Early Miocene. ETYMOLOGY: Named for Professor Li Chuankui for his many contributions to the study of Asiatic rodents. DIAGNOSIS: Similar to P. xinjiangensis in size, but differs in having well-developed roots, the absence of the metaflexid, and less hypsodonty. COMPARATIVE DESCRIPTION: The only preserved upper cheek tooth V16015.2 is a heavily worn M3 (fig. 7–A). The M3 trigon is kidney shaped, whereas it is trapezoidal in Distylomys burqinensis. The talon is much narrower than the trigon. At this stage of wear, the flexi are already fused and form a fossette. No cement is present in the fossette. The two strong roots of M3 are fused. The mandible (fig. 6) is similar to that of the type species, P. xinjiangensis. The diastema is short and shallow. The mental foramen opens dorsally and lies on the dorsal side of the diastema. In contrast, in P. xinjiangensis the mental foramen opens labially and occurs near the level of the dorsal shelf. The lower incisor is short, extending posteriorly to below m2 as in P. xinjiangensis and D. qianlishanensis, whereas it extends as far as m 3 in D. burqinensis. The tip of the lower incisor is broken and its cross section is subrectangular with flat anterior and lingual walls. The enamel thins and extends a short distance onto the labial and lingual walls. The p4 is not preserved in the holotype, but the alveolus indicates presence of three roots (fig. 6). The only known p4 is IVPP V16015.3 (fig. 7B). The trigonid is shaped like an isosceles triangle with gently concave labial and lingual margins. The anterolophid is short and blunt. The hypoflexid extends only halfway down the tooth, whereas the mesoflexid is much longer, extending to the root. The flexids are U-shaped and have no cement. In P. xinjiangensis, the flexids are V-shaped and cement filled. The talonid is wider than the trigonid; the talonid is slightly broken posteriorly, but what remains suggests absence of a metaflexid. This p4 has 3 roots. Although the p4 crown morphology is similar to that of dp4 of P. xinjiangensis except for the absence of the posterolophid, we prefer to consider this tooth as p4 because the roots are not splayed apart. If so interpreted, it is probable that p4 and dp4 have similar general crown morphology. The lower molars have the same bilophodont occlusal pattern as P. xinjiangensis, but lack the posterolophid. The flexids extend only to the alveolus, clearly showing welldeveloped roots in all the lower molars. In P. xinjiangensis, the flexids extend all the way into the tooth base, indicating reduced roots. COMMENTS: In the Chibaerwoyi locality, fossils were mostly collected from beds A and B (7–12 m, and 14–21 m from the base of the formation, respectively). P. lii was collected from Bed A. The exact stratigraphic level of P. xinjiangensis was uncertain, but most likely was collected from Bed A. However, P. lii is morphologically more primitive than P. xinjiangensis in having stronger roots, or less hypsodonty, and lack of posterolophid, suggesting an earlier occurrence.

Distylomys burqinensis, n. sp. Figures 2���5, table 1 DIAGNOSIS: Intermediate sized species, slightly larger than D. tedfordi and smaller than D. qianlishanensis. Differing from D. tedfordi in having p4 longer than m1, a more elongate anterolophid and absence of posterolophid on p4, m1 relatively wider with a more acute lingual apex of the trigonid. Differs from D. qianlishanensis in having a more acute anterolophid and subtriangular talonid on p4, lower molar trigonid triangular, and mental foramen higher on the mandible. HOLOTYPE: IVPP V16014.1, anterior partial skull with P4���M3 and associated mandible. REFERRED MATERIAL: IVPP V 16014.2, palate with dentition; V 16014.3, palate with broken left P4���M2 and right M1���M3; V 16014.4, palate with left M1���M2 and right P4���M2; V 16014.5, palate with left M1 and right M1���M2; V 16014.6, partial premaxilla with incisors; V 16014.7, left premaxilla with broken I2; V 16014.8���9, 2 right premaxillae with broken I2; V 16014.10���14, 5 left M1; V 16014.15, left M2; V 16014.16���21, 6 right M1; V 16014.22, right M2; V 16014.23���26, 4 right M3; V 16014.27���32, 6 left fragmentary mandibles with broken i2, and p4���m3; V 16014.33���34, 2 left fragmentary mandibles with broken i2 and p4���m2; V 16014.35���39, 5 left fragmentary mandibles with p4���m1; V 16014.40, left fragmentary mandible with p4; V 16014.41, left fragmentary mandible with broken p4���m1; V 16014.42, left fragmentary mandible with m1���m2; V 16014.43, left fragmentary mandible with m2���m3; V 16014.44, left m1; V 16014.45���46, 2 left m2; V 16014.47, left m3; V 16014. 48, right fragmentary mandible with broken i2 and p4���m3; V 16014.49, right fragmentary mandible with broken p4 ���m1 and complete m2���m3; V 16014.50���51, 2 right fragmentary mandibles with p4���m2; V 16014.52��� 55, 4 right fragmentary mandibles with p4; V 16014.56���57, 2 right fragmentary mandibles with m1���m2; V 16014.58, right fragmentary mandible with m2���m3; V 16014.59, right fragmentary mandible with broken m1; V 16014.60���61, 2 right p4; V 16014.62���64, 3 right m1; V 16014.65���66, 2 right m3. ETYMOLOGY: the species name refers to Burqin County, where site XJ200601 is located. LOCALITY AND AGE: Locality XJ200601 (47 �� 23.198 9 N, 86 �� 47.981 9 E), Burqin County, Xinjiang, China. Suosuoquan Formation, early Miocene. REPOSITORY: The specimens are stored in the collections of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing. DESCRIPTION: The holotype IVPP V16014.1 is a partial skull with articulated mandible. The skull preserves the anterior half, including the rostrum, palate, and partial frontal (fig. 2) and has been crushed and distorted, with the premaxilla shifted slightly lateroventrally. The incisive foramen is obscured due to distortion. Judging from what is preserved in the holotype and V16014.2 (fig. 4), it is very slender and narrow and ends posteriorly at the level of the center of the anterior zygomatic root. The base of the zygomatic root is preserved and shows that the zygomatic plate is not developed; its anterior margin is located far in front of P4 and its posterior margin is between P4 and M1. The tooth rows are convergent anteriorly. The palate is wider than the length of m1. The palatine-maxillary suture starts from anterior to M1. No palatine foramen can be recognized. In dorsal view, the nasal bones are narrow and extend posteriorly as far as the premaxillae. Laterally, the premaxillary-maxillary suture extends above M1. The infraorbital foramen, although broken, is evidently large and hystricomorphous. The frontals are flat and broadened relative to the width of the rostrum. The diastema of the mandible is shallow and shorter than the tooth row (fig. 3). The mental foramen is small and near the dorsal surface of the diastema. The mandible has a robust ventral masseteric crest, but there is no trace for the dorsal crest. The ventral crest terminates slightly anterior to the talonid of p4. Very little of the ascending ramus and angular process is preserved, but what remains suggests that the angular process is in the plane of the incisor within the horizontal ramus, as in other distylomyids. The dental formula is 1/1, 0/0, 1/1, 3/3. All cheek teeth are hypselodont and at least moderately worn, so that little is known about tooth cusps. The upper incisors are broad and flattened anteriorly. Upper cheek teeth are strongly recurved toward the root, and the curvature increases posteriorly (fig. 4). P4 is nonmolariform, unilobate, and somewhat trapezoidal in occlusal outline, with the posterior border slightly wider than the anterior one (fig. 4). Enamel is thinner at posterior margin. All upper molars are strongly bilophodont without the mure, so that the trigon and talon form two separated enamel loops. The trigon and talon are straight and parallel to each other. They are separated by a transverse central flexus, which is almost completely filled with cement. In side views, lateral and medial flexi persist to the base of the tooth crown. The trigon is trapezoidal with a flattened lingual wall and a gently convex labial one. The talon is subrectangular, slightly wider than long. Given the tooth curvature, the upper tooth crown inclines posteriorly. Each molar bears four transverse enamel lophs that form the cutting edges of the tooth. M1 is on average larger than M2 (table 1). In M1, the talon is wider but anteroposteriorly more compressed than the trigon. In M2 the talon is equal to or narrower than the trigon. M3 is larger than the preceding molars. In M3, the talon is reduced and much narrower, but slightly longer than the trigon. The lower incisors extend posteriorly in the jaw to below m3 (fig. 3). The incisor enamel is thick, relative to the depth of the incisor (fig. 5D���F). It has a flat buccal surface and similarly wraps around to cover the medial and lateral sides of the tooth to a significant extent. The enamel microstructure is multiserial (Korvenkontio, 1934; Wahlert, 1968, 1989; Martin, 1992, 1997), and more specifically it consists of multiserial Hunter-Schreger bands (HSB) with rectangular interprismatic matrix (IPM), a more derived type than the parallel IPM that has an acute angle to the bands (Martin, 1992; 1997). The enamel is 150��� 165 Mm thick, of which the portio interna (PI) and portio externa (PE) account for about 85% and 15%, respectively. Within the PI, each band consists mostly of four prisms. The HSB has a 50 �� ���60 �� angle to the enamel-dentine junction, as measured following Martin (1992). Unlike P4, which is nonmolariform, p4 is fully molariform and the largest of lower cheek teeth (fig. 4). The p4 trigonid is narrower than the talonid, with an acute anterior projection; its anterolingual edge is concave. The talonid is shorter but wider than the trigonid. No posterolophid is present except for three specimens that bear a shallow one. In 11 mandibles with check teeth, the premolar is less worn or in the same stage of wear as m1. Therefore we identify it as permanent p4, although Wang (1997) suggested that it may be deciduous p4. All lower molars are similar in overall morphology. The m1 is longer than m2, but shorter than m3. All molars are bilophodont but have the mure; therefore, the trigonid and talonid are confluent through a narrow neck. The trigonid is triangular, with a tapered and acute lingual apex and straight anterolingual edge. The mesoflexid and hypoflexid intrude transversely halfway across the crown and are filled by thin cement. In side view, both flexids extend to the base of the crown. In m1, the talonid is wider than the trigonid with gently convex posterior edge. In m2, the talonid is equal to or slightly narrower than the trigonid. In m3, the talonid is much narrower than the trigonid. COMMENT: The type species D. tedfordi was described by Wang (1988) on the basis of a single mandible, which was collected in 1928 by the Third Asiatic Expedition, AMNH, from the middle Miocene Tunggur Formation of the Tairum Nor Basin of Inner Mongolia. No additional material has since been referred to the species, restricting the comparison of the new materials to the lower jaw only. D. burqinensis is similar to D. tedfordi and is clearly closely related to it. The type specimen of D. tedfordi from Tunggur lies within the lower size range of D. burqinensis from Burqin. Morphologically, however, D. tedfordi differs from D. burqinensis in several aspects: p4 shorter than m1, having a less elongate anterolophid and subelliptical talonid, m1 relatively narrower with an inward curved anterolingual edge and more blunt lingual apex. In D. tedfordi, the posterolophid is distinct on p4; in Burqin specimens, it is distinct in three, and absent in eight. D. burqinensis is smaller than D. qianlishanensis and differs in having a more acute anterolophid and subtriangular talonid on p4; triangular trigonid on lower molars, and higher position of the mental foramen on the mandible. Wang (1988) thought D. tedfordi was morphologically more primitive than D. qianlishanensis because it possesses a well-developed posterolophid, a condition considered primitive. This, as Wang noted, is inconsistent with the stratigraphic occurrences of the species because D. tedfordi was found in later deposits (middle Miocene) than D. qianlishanensis (late Oligocene). D. burqinensis, with an early Miocene age, also lacks the posterolophid or has only an incipient one. We therefore offer an alternative interpretation: the presence of the posterolophid is a derived character within the genus, appearing in species with a younger age. If this is true, D. burqinensis is morphologically intermediate between D. qianlishanensis and D. tedfordi, but is more similar to the latter. It should be noted that size decreases in this lineage., Published as part of Bi, Shundong, Meng, Jin, Wu, Wenyu, Ye, Jie & Ni, Xijun, 2009, New Distylomyid Rodents (Mammalia: Rodentia) from the Early Miocene Suosuoquan Formation of Northern Xinjiang, China, pp. 1-20 in American Museum Novitates 3663 on pages 4-11, DOI: 10.1206/665.1, http://zenodo.org/record/4735501, {"references":["Korvenkontio, V. A. 1934. Mikroskopische Untersuchungen an Nagerincisiven unter Hinweis auf die Schmelzstruktur der Backenzahne. Annales Zoologici Societatis Zoologicae-Botanicae Fennicae ' Vanamo' 2: 1 - 274.","Wahlert, J. H. 1968. Variability of rodent incisor enamel as viewed in thin section, and the microstructure of the enamel in fossil and Recent rodent groups. Breviora of the Museum of Comparative Zoology 309: 1 - 18.","Wahlert, J. H. 1989. The three types of incisor enamel in rodents. In C. C. Black and M. R. Dawson (editors), Papers on fossil rodents in honor of Albert Elmer Wood. Natural History Museum of Los Angeles County Science Series 33: 7 - 16.","Martin, T. 1992. Schmelzmikrostructur in den incisiven alt- und neuweltlicher hystricognather Nagetiere. Palaeovertebrata Memoire Extraordinaire: 1 - 168.","Martin, T. 1997. Incisor enamel microstructure and systematics in rodents. In W. V. Koenigswald and P. M. Sander (editors), Tooth enamel microstructure, 163 - 175. Rotterdam: Balkema.","Wang, B. - Y. 1997. The mid-Tertiary Ctenodactyloidea (Rodentia, Mammalia) of eastern and central Asia. Bulletin of the American Museum of Natural History 234: 1 - 88.","Wang, B. - Y. 1988. Distylomyidae fam. nov. (? Ctenodactyloidea, Rodentia) from Nei Mongol, China. Vertebrata Palasiatica 26 (1): 35 - 49."]}

Prodistylomys Wang and Qi, 1989 TYPE SPECIES: Prodistylomys xinjiangensis Wang and Qi, 1989. INCLUDED SPECIES: Prodistylomys lii, n. sp.; P. wangae, n. sp. GEOLOGICAL RANGE: Early Miocene. GEOGRAPHIC DISTRIBUTION: Xinjiang, China EMENDED DIAGNOSIS: M3 bilophodont without the mure and asymmetrical with the corresponding lower molar, as in Distylomys. Differs from Distylomys in having rooted, hypsodont cheek teeth, M3 trigon semilunar shaped in outline, p4 with shorter trigonid, m1���2 with short trigonid and narrower talonid than the trigonid, thinner cement in hypoflexid and mesoflexid in lower molars., Published as part of Bi, Shundong, Meng, Jin, Wu, Wenyu, Ye, Jie & Ni, Xijun, 2009, New Distylomyid Rodents (Mammalia: Rodentia) from the Early Miocene Suosuoquan Formation of Northern Xinjiang, China, pp. 1-20 in American Museum Novitates 3663 on page 11, DOI: 10.1206/665.1, http://zenodo.org/record/4735501, {"references":["Wang, B. - Y., and T. Qi. 1989. Prodistylomys gen. nov. (Distylomyidae,? Ctenodactyloidea, Rodentia) from Xinjiang, China. Vertebrata Palasiatica 27 (1): 28 - 36."]}

Distylomys Wang, 1988 TYPE SPECIES: Distylomys tedfordi Wang, 1988. INCLUDED SPECIES: Distylomys qianlishanensis Wang, 1988; D. burqinensis, n. sp. GEOLOGICAL RANGE: Late Oligocene to middle Miocene. GEOGRAPHIC DISTRIBUTION: Inner Mongolia, Gansu, and Xinjiang, China. EMENDED DIAGNOSIS: Incisive foramen small; tooth rows convergent anteriorly; mental foramen in diastema; distinct ventral masseteric crest extending below p4; sciurognathous angular process; dental formula 1/1, 0/0, 1/1, 3/3; cheek teeth hypselodont with asymmetrical pattern; P4 nonmolariform; upper molars bilophodont without the mure; p4 molariform; lower molars bilophodont with the mure; mesoflexid and hypoflexid deep and wide, opposite to each other and with cement; worn occlusal surface of cheek teeth smoothly concave with enamel thin or interrupted at the posterior edge of teeth., Published as part of Bi, Shundong, Meng, Jin, Wu, Wenyu, Ye, Jie & Ni, Xijun, 2009, New Distylomyid Rodents (Mammalia: Rodentia) from the Early Miocene Suosuoquan Formation of Northern Xinjiang, China, pp. 1-20 in American Museum Novitates 3663 on page 4, DOI: 10.1206/665.1, http://zenodo.org/record/4735501, {"references":["Wang, B. - Y. 1988. Distylomyidae fam. nov. (? Ctenodactyloidea, Rodentia) from Nei Mongol, China. Vertebrata Palasiatica 26 (1): 35 - 49."]}

Prodistylomys wangae, n. sp. Figure 8, table 1 HOLOTYPE: IVPP V16016.1, right fragmentary mandible with broken incisor and complete p4–m2. REFERRED MATERIAL: IVPP V 16016.2, right M3; V 16016.3, left fragmentary mandible with broken i2–p4, and m1–m2; V 16016.4, right fragmentary mandible with broken i2 and p4–m2; V 16016.5, left m1. LOCALITY AND AGE: Locality XJ200601 (47 ° 23.198 9 N, 86 ° 47.981 9 E) in Burqin County of Xinjiang, Suosuoquan Formation, early Miocene. ETYMOLOGY: The species name, wangae, is in honor of our colleague, Wang Banyue, for her contribution to the study of distylomyids. REPOSITORY: The specimens are stored in the collections of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing. DIAGNOSIS: Slightly larger than P. lii and P. xinjiangensis. Differs from P. lii in having weak roots, thicker cement, rounded lingual apex of m1 trigonid, shorter talonid on m2. Differs from P. xinjiangensis in having thicker cement, rounded lingual apex of m1 trigonid, and the absence of the metaflexid on lower molars. DESCRIPTION: The M3 trigon is semicircular in outline, with a straight posterior margin (fig. 8A). The enamel is very thick, becoming thinner on the posterior margin. The hypoflexus extends to the base of the crown and becomes shallower while approaching the base. The mesoflexus extends L of the height of the crown and is fused toward the base, suggesting a rudimentary root. On the contrary, in P. lii, both flexi are fused, showing a well-developed root. The talon is circular shaped, much narrower than the trigon. The state of the masseteric crest is typical for the genus; the ventral crest is strong and extends under p4 and the dorsal crest is absent. The lower incisor extends posteriorly to underneath m3. The lower incisor is similar in its general morphology and microstructure to that of Distylomys burqinensis except that the pulp cavity is significantly smaller (fig. 5A, D). The p4 is shorter than m1 (fig. 8C). The trigonid is much narrower than the talonid compared with that in P. lii and P. xinjiangensis and has a stout anterolophid. The anterolophid is blunt and lies well toward the labial side of the tooth rather than in the center. Only thin cement is present in the flexids. The talonid has a vestigial posterolophid. Only m1 and m2 are preserved (fig. 8C; table 1). The lower molars are bilophodont, and hypsodont. The crown expands toward the base. The trigonid is subelliptical with a rounded anterior wall and a long axis oriented slightly anterolabial-posterolingually. The flexids are Ushaped with thin cement; the mesoflexid shallows but extends all the way to the base, and the hypoflexid extends down 2/3 of the height of the crown where it closes, indicating a rudimentary root (fig. 8B). The talonid is narrower than the trigonid, and is compressed with acute labial and lingual angles. The m1 and m2 are identical in crown morphology, but m2 is shorter than m1, and the lingual apex of its trigonid is more acute. COMMENT: Although the Xinjiang specimens are very similar to Distylomys in crown morphology, the rudimentary roots of the cheek teeth, shorter trigonid and narrower talonid on lower molars, and thinner cement suggest that it is better to assign the specimens to the genus Prodistylomys rather than to Distylomys. P. wangae differs substantially from P. lii in showing a tendency to the loss of roots and subelliptical trigonid. It differs from P. xinjiangensis in the absence of the posterolophid (or metaflexid) and subelliptical trigonid.

Three new distylomyid species, Distylomys burqinensis, Prodistylomys wangae, and P. lii, are described from the Suosuoquan Formation, early Miocene, of Xinjiang Province, northwestern China. Previously unknown cranial materials and upper dentitions add new information for the higher-level taxonomy of distylomyid rodents. Based on these new discoveries, the Family Distylomyidae is resurrected. These fossils demonstrate that distylomyids have a combination of primitive “ctenodactylid” characters and derived hystricognathous ones, possibly indicating a close affinity with South American caviomorph rodents and thereby offering new evidence to challenge the hypothesis that the traditional “Ctenodactyloidea” are monophyletic. Prodistylomys lii was recovered from Suosuoquan mammal assemblage III (magnetostratigraphically dated as 21.69–21.16 Mya) at the Chibaerwoyi locality. Distylomys burqinensis and Prodistylomys wangae were collected from a new fossiliferous locality, Locality XJ200601 of Burqin Coun...

Major crown-groups of rodents were well established in the early Tertiary, and fossils provide an invaluable window into their evolutionary history. The main focus of this project was to perform a cladistic assessment of the dental evidence for early Tertiary rodent cladogenesis – the masticatory apparatus and teeth are the most frequently preserved anatomical features in the fossil record. We focused on groups that existed in a period corresponding to their early history, combining fossils belonging to extinct lineages and to stem-groups leading to modern lineages. While the monophyly of some groups is not systematically explored, our results have important implications for high-level rodent relationships and systematics. These results are consistent with those of recent molecular phylogenies and reliably congruent with the stratigraphic record, thus enhancing the pertinence of dental characters for phylogenetic inference. Our approach provides evidence of a fundamental dichotomy in early rodent history. Two major clades have been identified: (1) the earliest ‘ctenodactyloid’ (Ctenodactylidae, Chapattimyidae, Yuomyidae, Diatomyidae) and hystricognathous (Tsaganomyidae, Baluchimyinae, ‘phiomorphs’, ‘caviomorphs’) rodents, and (2) the earliest ‘ischyromyoid’ rodents with their closest relatives (Muroidea + Dipodoidea + Geomyoidea + Anomaluroidea + Castoroidea + Sciuravidae + Gliroidea, and Sciuroidea + Aplodontoidea + Theridomorpha). This topology has led us to endorse Ctenohystrica as the first clade and propose a new taxon, Ischyromyiformes, for the second. Although minimized in our working hypothesis, the homoplasy in dental characters remains significant. However, a number of homoplasic characters reveal structuring in their internal distribution, allowing us to discern evolutionary morphological patterns, notably the pentalophodonty of molars, zygomasseteric complex and incisor enamel microstructure. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 142, 105–134.

The ctenodactylids from the Lower and Middle Miocene of Saudi Arabia are represented by two species: Sayimys intermedius (Sen and Thomas, 1979) and Sayimys assarrarensis sp. nov. This new taxon differs from the other species of Sayimys by its larger size together with an association of characters such as the presence of a metalophulid II in d4 and the strength of the anteroloph and posteroloph in P4. A cladistic analysis involving Prosayimys flynni, Sayimys obliquidens, S. assarrarensis sp. nov., S. intermedius, S. sivalensis, S. baskini, and Metasayimys curvidens is provided. Sayimys assarrarensis sp. nov. nests between Sayimys obliquidens and Metasayimys curvidens as a relatively primitive taxon.

A new species of Sayimys (Ctenodactylidae, Mammalia), Sayimys giganteus sp. nov., is described from the Early Miocene localities of Keseko¨ y 1, Keseko¨ y 2, and Hisarcik (Turkey). Sayimys giganteus sp. nov. differs from other known species of Sayimys by its larger size and several plesiomorphies (e.g., metalophulid II on dp4, strong anterolophid and posterolophid on P4, and a long paraflexus and metaflexus on upper molars), but also in the presence of some derived characters. Two species of Sayimys are currently recognized in Turkey: Sayimys cf. Sayimys intermedius (at Pas¸alar, Middle Miocene) and Sayimys giganteus sp. nov. Based on a cladistic analysis involving all known species of Sayimys, Metasayimys, and Prosayimys, Sayimys giganteus sp. nov. emerges as the sister taxon of Sayimys obliquidens.

Ctenodactylids are common elements of Early-Middle Miocene mammal faunas of the Indian subcontinent, West Asia, and North Africa. They are of great interest for biostratigraphical correlations and palaeogeographical relationships between these areas. The study of new ctenodactylid remains from Early-Middle Miocene localities of Saudi Arabia, Turkey, and Chios Island has revealed that the systematics of the Early-Middle Miocene ctenodactylids from the Indian subcontinent are problematic. Seven species belonging to two genera have been recognized so far in the Indo-Pakistani Mio-Pliocene: Prosayimys flynni Baskin 1996, Sayimys minor de Bruijn et al. 1981, Sayimys intermedius (Sen & Thomas 1979), Sayimys sivalensis (Hinton 1933), Sayimys chinjiensis Baskin 1996, Sayimys perplexus Wood 1937, and Sayimys badauni Vasishat 1985. We consider that, at best, only five ctenodactylid species are recognizable in the Mio-Pliocene of the Indian subcontinent: Prosayimys flynni Baskin 1996, Sayimys baskini nov. sp., Sayimys intermedius (Sen & Thomas 1979), Sayimys sivalensis (Hinton 1933), and perhaps Sayimys badauni Vasishat 1985.

Pectinator spekei Blyth, 1856. J. Asiat. Soc. Bengal for 1855, (2)24:294 [1856]. TYPE LOCALITY: Somalia (between Goree Bunder and Nogal), ca 09°N, 47°E. DISTRIBUTION: Ethiopia, Somalia, Djibouti. SYNONYMS: legerae de Beaux, 1934; meridionalis de Beaux., Published as part of Fritz Dieterlen, 1993, Order Rodentia - Family Ctenodactylidae, pp. 761 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 761, DOI: 10.5281/zenodo.7353064, {"references":["de Beaux, O. 1934. Mammiferi raccolti dal Prof. G. Scorteccinella Somalia Italiana Centrale e Settentrionale Nel 1931 con l'aggiunta di aleuni mammiferi della Somalia Italiana meridionale. Atti della Societa Italiana De Scienze Naturali e del Museo Civico Di Storia Naturale in Milano, 73: 261 - 300."]}

Ctenodactylus vali Thomas, 1902. Proc. Zool. Soc. Lond., 1902(2):11. TYPE LOCALITY: Libya, "Wadi Bey" (NW of Bonjem, Tripoli). DISTRIBUTION: S Morocco, W Algeria, NW Libya. SYNONYMS: joleaudi Heim de Balsac, 1936. COMMENTS: Corbet (1978c: 160) included vali in gundi, but George (1982) and Corbet and Hill (1991) listed both as distinct species., Published as part of Fritz Dieterlen, 1993, Order Rodentia - Family Ctenodactylidae, pp. 761 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 761, DOI: 10.5281/zenodo.7353064, {"references":["Corbet, G. B. 1978 c. The mammals of the Palaearctic region: A taxonomic review. British Museum (Natural History), London, 314 pp.","Corbet, G. B., and J. E. Hill. 1991. A world list of mammalian species. Third ed. British Museum (Natural History) Publications, London, 243 pp."]}

Pectinator Blyth, 1856. J. Asiat. Soc. Bengal for 1855, (2)24:294 [1856]. TYPE SPECIES: Pectinator spekei Blyth, 1855. SYNONYMS: Petrobates Heuglin, 1860., Published as part of Fritz Dieterlen, 1993, Order Rodentia - Family Ctenodactylidae, pp. 761 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 761, DOI: 10.5281/zenodo.7353064

Massoutiera mzabi (Lataste, 1881). Bull. Soc. Zool. Fr., 6:314. TYPE LOCALITY: Algeria, Ghardaia. DISTRIBUTION: SE Algeria, SW Libya, NE Mali, N Niger, N Chad. SYNONYMS: harterti Thomas, 1913; rothschildi Thomas and Hinton, 1921., Published as part of Fritz Dieterlen, 1993, Order Rodentia - Family Ctenodactylidae, pp. 761 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 761, DOI: 10.5281/zenodo.7353064, {"references":["Hinton, M. A. C. 1921. Some new African mammals. Annals and Magazine of Natural History, ser. 9, 7: 368 - 373."]}

Felovia vae Lataste, 1886. Le Naturaliste, 7(36):287. TYPE LOCALITY: Senegal, upper Senegal River, Medina Dist., Felou. DISTRIBUTION: Senegal, Mauritania, Mali., Published as part of Fritz Dieterlen, 1993, Order Rodentia - Family Ctenodactylidae, pp. 761 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 761, DOI: 10.5281/zenodo.7353064

Massoutiera Lataste, 1885. Le Naturaliste, 7(3):21. TYPE SPECIES: Ctenodactylus mzabi Lataste, 1881., Published as part of Fritz Dieterlen, 1993, Order Rodentia - Family Ctenodactylidae, pp. 761 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 761, DOI: 10.5281/zenodo.7353064

Felovia Lataste, 1886. Le Naturaliste, 7(36):287. TYPE SPECIES: Felovia vae Lataste, 1886. COMMENTS: Proposed as a subgenus of Massoutiera; recognized as a valid genus by Thomas (1913a:31) and St. Leger (1931:978)., Published as part of Fritz Dieterlen, 1993, Order Rodentia - Family Ctenodactylidae, pp. 761 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 761, DOI: 10.5281/zenodo.7353064, {"references":["Thomas, O. 1913 a. Ernst Hartert's expedition to the Central Western Sahara. Mammals. Novitates Zoologicae, Triung, 20: 28 - 33.","St. Leger, J. 1931. A key to the families and genera of African Rodentia. Proceedings of the Zoological Society of London, 1931: 957 - 997."]}

Fritz Dieterlen (1993): Order Rodentia - Family Ctenodactylidae. In: Don E. Wilson, DeeAnn M. Reeder (Eds): Mammal Species of the World (2nd Edition). Washington and London: Smithsonian Institution Press: 761, ISBN: 1-56098-217-9, DOI: http://doi.org/10.5281/zenodo.7353064

Ctenodactylus Gray, 1830. Spicil. Zool., p. 10. TYPE SPECIES: Ctenodactylus massonii Gray, 1830 (= Mus gundi Rothmann, 1776). COMMENTS: Reviewed by W. George (1979)., Published as part of Fritz Dieterlen, 1993, Order Rodentia - Family Ctenodactylidae, pp. 761 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 761, DOI: 10.5281/zenodo.7353064, {"references":["Gray, J. E. 1830 - 1834. Illustrations of Indian zoology; chiefly selected from the collection of Major-General Hardwicke. Treuttel, Wurtz, Treuttel, Jun. and Richter, London, [vol 1, 1830 - 1832; vol 2, 1833 - 1834]."]}

Family Ctenodactylidae REVIEWED BY: H. Levenson (HL). COMMENT: Reviewed by George, 1979, Zool. J. Linn. Soc., 65:261 -280. ISIS NUMBER: 5301410033000000000., Published as part of James H. Honacki, Kenneth E. Kinman & James W. Koeppl, 1982, Order Rodentia (Part 6), pp. 560-594 in Mammal Species of the World (1 st Edition), Lawrence, Kansas, USA :Alien Press, Inc. & The Association of Systematics Collections on page 594, DOI: 10.5281/zenodo.7353039

Felovia Lataste, 1886. Le Naturaliste, 3:287. ISIS NUMBER: 5301410033002000000., Published as part of James H. Honacki, Kenneth E. Kinman & James W. Koeppl, 1982, Order Rodentia (Part 6), pp. 560-594 in Mammal Species of the World (1 st Edition), Lawrence, Kansas, USA :Alien Press, Inc. & The Association of Systematics Collections on page 594, DOI: 10.5281/zenodo.7353039

Pectinator Blyth, 1855. J. Asiat. Soc. Bengal, 24: 294. ISIS NUMBER: 5301410033004000000., Published as part of James H. Honacki, Kenneth E. Kinman & James W. Koeppl, 1982, Order Rodentia (Part 6), pp. 560-594 in Mammal Species of the World (1 st Edition), Lawrence, Kansas, USA :Alien Press, Inc. & The Association of Systematics Collections on page 594, DOI: 10.5281/zenodo.7353039