The Jebel Qatrani Formation (also Gebel Qatrani, Gabal Qatrani or Djebel Qatrani) is a geologic formation located in the Faiyum Governorate of central Egypt. It is exposed between the Jebel Qatrani escarpment and the Qasr el Sagha escarpment, north of Birket Qarun lake near Faiyum. The formation conformably overlies the Qasr el Sagha Formation and is topped by the Widan el Faras Basalt. The age of the formation has been subject to debate, but the most recent research indicates that it covers both the latest parts of the Eocene and the Early Oligocene, spanning over the boundary between these two time periods.
The geology and fauna of this formation gives a good idea of the environment and animals present during this time period. Research suggests that the Jebel Qatrani Formation featured a mix of subtropical to tropical forest, lowland swamps and marshes, ponds and rivers that would empty northward into the Tethys Sea. This is supported by the presence of water-dependent fauna including podocnemidid turtles, crocodilians, sea cows, various fish, jacanas, early flamingo-relatives, ospreys, herons and shoebills.
Besides these, the fossil record of the Jebel Qatrani Formation is especially well known for its value to understanding the early evolution of many modern mammal groups. Primates are represented by over a dozen genera, several forms of early elephants have been recovered from the sediments including the terrestrial Phiomia and the semi-aquatic Moeritherium. The fossil rodents of the formation meanwhile are thought to be an important link between the African phiomorphs (dassies, old world porcupines, mole rats and cane rats) and the caviomorphs of South America (capybaras, chinchillas and new world porcupines). Besides these early members of groups that would later rise to prominence, the formation was also home to a variety of unique groups no longer found today or only found in a greatly diminished diversity. This includes the enigmatic, possibly carnivorous ptolemaiids, large hyaenodonts, a vast number of highly diverse hyracoids including species the size of rhinos, anthracotheres and the bizarre embrithopodArsinoitherium.
Geography and history
Outcrops of the Jebel Qatrani Formation are present in the northern Fayum Depression southwest of Cairo.[1] The Fayum Depression is an oasis west of the Nile in northern Egypt.[2]
The formations of the Fayum have been studied for a significant amount of time by numerous paleontologists, with research dating back to as early as the 19th century. During this time the region was studied extensively by scientists including but not limited to Charles William Andrews, Henry Fairfield Osborn, René Fourtau and Ernst Stromer. Among the first names for what is now known as the Jebel Qatrani formation was the “Fluvio-Marine Series”, as coined by Hugh J. L. Beadnell. However, despite the bulk of research conducted in the late 19th and early 20th century, the Fayum localities would eventually enter a period of obscurity following the outbreak of World War I which continued throughout the mid 20th century and World War II. Research resumed during the 1960s, following an expedition under Elwyn LaVerne Simons.[2] Previously, the formations of the region had been primarily known for the preservation of mammals, but Birds were also known from few specimens uncovered in the early 20th century. During the 60s, improved collection methods and additional expeditions by the Yale and Duke University gathered much additional material in association with the Egyptian Geological Survey and the General Petroleum Company.[1] Around the 70s, the scope of the expedition was broadened to account for more diverse fields of study, leading to more precise datings of the strata.[2]
Geology and stratigraphy
The formation overlies the Eocene Qasr el Sagha Formation and is overlaid by the Oligocene Widan el Faras Basalt. The formation contains at least two major fossil bearing layers, one in the upper sequence, which is used to refer to the top layers of the formation, and a second in the lower sequence. These two layers have also been called the Upper and Lower Fossil Wood Zones in older publications. Both sequences of the Jebel Qatrani Formation are separated from one another by the so-called Barite Sandstone, a layer with a thickness of 4–10 m (13–33 ft).[1][2]
The dating of the Jebel Qatrani Formation has historically been under debate, with some research having placed it either entirely within the Eocene or Oligocene and some arguing that it spans both periods. Rasmussen and colleagues for instance argued that the central Barite Sandstones separating both fossil bearing layers mark the exact Eocene-Oligocene Boundary. Part of the reasoning for this connects to the primate fauna of the formation, with propliopithecids and parapithecines only appearing in the upper localities. Other dating methods meanwhile have generally not been applicable. According to Seiffert, the mammal fauna of the formation on its own is too endemic and marine invertebrates are absent, preventing biostratigraphic dating. Radioisotopic dating was conducted on the overlying Widan el Faras Basalt, however the results of this suggested an age of 23.6 million years for its lower units, much younger than prior estimates for the Jebel Qatrani Formation. However, in a 2006 publication Seiffert draws a comparison between the Fayum fauna and the fossil record of the Ashawq Formation in Oman, which notably preserved vertebrates as well as foraminifera useful in dating. Foraminifera biostratigraphy and magnetostratigraphy suggest that the examined localities in Oman date to approximately 31-31.5 (Taqah locality) and 33.7-33.3 Ma (Thaytiniti locality). Seiffert argues that the mammal fauna from Oman most closely resembles those found in the oldest localities of the Lower Sequence of the Jebel Qatrani Formation (L-41) and the oldest localities of the Upper Sequence (quarries G and V). The hyraxes Thyrohyrax and Saghatherium occur in both formations, as does the primate Moeripithecus. More generally, both formations preserve propliopithecids and parapithecineparapithecids as well as oligopithecids. While the former two groups are restricted to the younger Fayum sequence, the latter is the most common primate family in the older sediments. Assuming the traditional interpretation of the Jebel Qatrani Formation, this would mean that many of these taxa would have had to appear 2 to 4 million years earlier in Egypt than in Oman, which is considered to be unlikely by Seiffert. According to them the formation spans approximately 8 million years, with its oldest localities situated in latest Eocene strata. Locality BQ-2 has been estimated to be 37 million years old (early Priabonian), while L-41 falls into an age range of 34.8–33.7 million years old, a timespan that includes the Eocene-Oligocene Boundary. Although an earliest Oligocene age could not be disproven by Seiffert, he argues that a latest Eocene age should be considered more likely based on an unconformity present just above the locality (one also acknowledged as a possible candidate for the EOB by Rasmussen). This means that only the lower 48 m (157 ft) of the formation are Eocene in age, including both the BQ-2 and L-41 localities. The remainder of the Lower Sequence, as well as the entire Upper Sequence, would subsequently fall within the Oligocene. The position of quarries A and B in regards to the boundary is ambiguous, however Quarry E on the other hand is considered without doubt Oligocene (ca. 33 Ma) in age by Seiffert.[3]
Paleoenvironment
The environment of the Jebel Qatrani formation has been described as a subtropical to tropical lowland plain by Bown, who further suggests the presence of streams and ponds. Based on the fossil bird remains, which includes the fossils of a variety of animals highly associated with water (ospreys, early flamingos, jacanas, herons, storks, cormorants and shoebills), Rasmussen and colleagues inferred that the environment featured slow-moving freshwater with a substantial amount of aquatic vegetation, which matches the prior hypothesis. Although lithology suggests that most fossils were deposited on sandbanks after being transported by currents, the authors argue that swamps could have easily formed along the banks of the river that was present during the Oligocene and may account for the mudstone found in certain quarries. They furthermore suggest that the fossil birds of Fayum, due to their affinities with modern groups, should be considered a more valuable indicator of the environment when compared with the fossil mammals, many of which belonged to families lacking modern examples. The absence of other birds typical for such an environment may be explained either through sampling bias or due to the fact that said groups had simply not yet been present in Oligocene Africa. Generally, Rasmussen and colleagues compare the environment of Jebel Qatrani to freshwater habitats in modern Central Africa.[1] The discovery of snakehead fossils seem to support Rasmussen's interpretation, as the genus Parachanna today prefers slow-moving backwaters with plenty of vegetation. Other fish present meanwhile, notably Tylochromis, suggest that deep, open water was likewise present. The river channels may have been overgrown with reeds, papyrus and featured floating vegetation like water lilies and Salvinia.[4] In a 2001 paper Rasmussen et al. argued that the sandstone and mudstone of the formation likely formed as sediments were aggraded by a system of river channels that emptied towards the west into the Tethys. Here they reconstructed the environment as a tropical lowland swamp forest intermingled with marshes. They furthermore suggest that the environment would have experienced monsoons.[5] Overall this indicates that this region was a part of an extensive belt of tropical forest that stretched across what is now northern Africa, which would gradually give rise to open woodland and even steppe the further one was to travel inland.[2]
Different teeth belonging to Characiformes, they are common across both fossil bearing members. A large range of tooth morphotypes is present in the formation, however this may not reflect the actual diversity of African tetra species present.
Its absence from the lacustrine L-41 environment might indicate that the water was too shallow. Modern Lates can grow large and prefer large lakes and rivers.[8]
Three skulls and various postcranial remains, predominantly fin spines.
The three known skulls are approximately the same size, but may not represent the same taxon. The postcranial elements indicate a greater size range. In some aspects the Jebel Qatrani catfish resemble the genus Fajumia.
A partial plastron with articulated peripheral elements of the upper shell.
A side-necked turtle of the family Podocnemididae with a high-domed shell likely similar to tortoises. It may be a related taxon to specimen UCMP 42008, from the Miocene of Kenya.
A side-necked turtle of the family Podocnemididae previously known as "Stereogenys" lybica. The holotype specimen, among the best preserved turtle shells from Fayum, was thought to be lost before being rediscovered and used to erect a new genus. Several additional specimens are known from the Jebel Qatrani and its underlying formations.
A large and broad-snouted species of crocodilian incorrectly assigned to Crocodylus. A second Fayum crocodile, "Crocodylus" articeps, has been considered a younger individual of this species by Christopher Brochu.
A side-necked turtle of the family Podocnemididae that may be a related taxon to specimen UCMP 42008. It is possible that Dacquemys represents skull material of Albertwoodemys.
An early genus of gavialoid common in the formation. Two species have originally been named from Jebel Qatrani,Eogavialis gavialoides and Eogavialis tenuirostre (both originally as Tomistoma), however recent research suggests that all Fayum Eogavialis species including those of other formations in the region may simply represent a single species.[2]
Various remains of the plastron and carapace as well as skull material.
A side-necked turtle of the family Podocnemididae, similar to Erymnochelys and previously assigned to said genus. The type specimen, an anterior plastron, has potentially been lost. They are among the most common fossils in the quarries L-41, I and M.
I single bone described by Smith et al. and originally assigned to the genus Varanus. Later research by Holmes et al. suggests it was a stem-varanid, distinct from other remains found in the formation.
Isolated bones described by Holmes et al. and considered to be part of the modern genus Varanus. They argue that this represents the oldest known member of the genus and indicates an African origin for modern monitor lizards.
A bird of prey similar in size and morphology to the modern sea eagles. The early strata of the formation indicate closer proximity to the shore, possibly supporting a lifestyle similar to modern Haliaeetus species.
A large species of jacana, exceeding all modern taxa in size but still smaller than Nupharanassa bulotorum. The Fayum jacanas already show signs of a lifestyle like that of their modern relatives and subsequently may indicate a dense floating vegetation.
Multiple specimens preserving the tarsometatarsus.
A large species of jacana, between 30 and 35% larger than the largest extant species, the bronze-winged jacana.
N. tolutaria
Lower Sequence
Quarry E
The distal end of a tarsometatarsus.
A smaller relative of Nupharanassa bulotorum, it is distinguished by its much smaller size and older age. It is the only known jacana in the lower sequence of the Jebel Qatrani Formation.
A nearly complete rostrum with mandible and partial cranium and the distal end of a right tibiotarsus.
A large stork comparable in size to the modern jabiru and marabou stork. While the type material bears great resemblance to the extant saddlebill, a tibiotarsus found in a different quarry shares no similarities with any modern taxa and may or may not belong to Palaeoephippiorhynchus.
The distal end and partial shaft of a tarsometatarsus.
A bird bearing resemblance to modern crowned cranes, cranes of the genus Grus and the limpkin. Its size is between that of the limpkin and the demoiselle crane, although closer to the former.
Various fragmentary leg bones including the distal end of a tibiotarsus and the distal end of a tarsometatarsus.
An enigmatic large groundbird comparable in size to a modern rhea. It was initially thought to be a type of ratite, but its relationship with other birds has repeatedly been questioned. Stromeria fajumensis, found in the same formation, is thought to be synonymous with Eremopezus.
A partial rostrum, a distal tarsometatarsus of a juvenile specimen and the first phalanx of the third toe.
A medium-sized heron comparable in size to the reddish egret and the great white egret. The lack of overlapping material means that it is uncertain if these fossils represent one or several species.
A bird whose remains are described as being identical to that of the extant black-crowned night heron, indicating that night herons diverged from other herons at least 31 million years ago.
Multiple specimens including the tibiotarsus and parts of the metacarpals.
Several bones of the Fayum phoenicopteriform show both similarities to derived flamingos as well as to the more basal Palaeolodus, which Rasmussen and colleagues considered Phoenicopterids rather than placing it within its own family. The material suggests a bird approximately the size of Palaelodus gracilipes.
An indetermined cormorant showing a more gradually tapering and more strongly hooked beak. Among modern cormorants, it most closely resembles the guanay cormorant.
A large anthracothere from the uppermost levels of the formation, it may have been most closely related to B. fraasi, either through anagenesis or by splitting from the B. fraasi lineage.
B. fraasi
Upper Sequence
Quarry I
A species of Bothriogenys arising from B. gorringei. It may have either split into two lineages or given rise to B. andrewsi through anagenesis.
B. gorringei
Lower and Upper Sequence
Quarry A, B & M
Originally described based on a mandible.
The oldest species of Bothriogenys in Jebel Qatrani, it may have split into two lineages giving rise to B. fraasi and B. rugulosus. It may have been a semi-aquatic browser or grazer, feeding primarily on foliage. Though typical for the lower sequence, material tentatively assigned to this species have been recovered from Quarry M as well.
B. rugulosus
Upper Sequence
A species of Bothriogenys that likely evolved from B. gorringei.
A bat of uncertain affinities. It was the first fossil bat discovered in Africa and the largest bat of the Fayum succession, weighing up to 120 g (4.2 oz). This puts it within the size range of the Egyptian fruit bat.
Just above Quarry L-41 to Quarry M, spanning most of the sequence.
A large arsinoitheriidembrithopod well known for its two horns. A large amount of material is known and in the past a second species from Jebel Qatrani, A. andrewsi, has been proposed. Some researchers however consider it to be a synonym of A. zitteli with the differences possibly being caused by sexual dimorphism.
A member of the Hyainailourinae, it was originally described as Pterodon leptognathus. It was smaller than the two other "Pterodon" species from Jebel Qatrani and Metapterodon.
A. nefertiticyon
Lower Sequence
Quarry L-41
A complete cranium as well as a palate and dentary.
A second species of Akhnatenavus smaller than A. leptognathus. The skull also appears to have been much shorter than in the type species. Calculations resulted in an average bodymass of 19.2 kg (42 lb), approximately as large as a Eurasian lynx or wolverine.
Although named in 1910, A. altidens was not properly described until 1911. A mandible was also referred to this species, but this decision has been considered dubious by Lange-Badré and Böhme.
A. macrognathus
Lower Sequence
Quarry A & B
Skulls and mandibles
A hyaenodont originally described as a species of Pterodon.
A teratodontine hyaenodont approximately as heavy as a modern red fox or American badger. Although the name was coined in a dissertation in 1994, it was not formally described until 2016.
Erected by Holroyd as a species of Metapterodon, it was even then noted to be possibly distinct. Morales and Pickford later raised it to a distinct genus. There may be additional material from Quarry B in the lower sequence, however the assignment of said fossils is only tentative.
A smaller species of Masrasector from older deposits. Its estimated body size was within the range of modern striped skunks and small-spotted genets. The limb bones indicate it was a fast runner that could have hunted the local rodents.
Named as a species of Hyaenodon, it was eventually placed in Metapterodon by Holroyd. While Morales and Pickford restrict the genus to the Miocene and place Holroyd's other species in separate genera, they do not mention M. brachycephalus.
Mandibles, a rostrum and an assigned neck vertebra.
The first hyaenodont described from Fayum, later analysis showed that it was much more derived than Pterodon dasyuroides, the type species. Consequently, a different genus name is required.
P. phiomensis
Lower Sequence
Quarry A
A mandible smaller than that of "P." africanus.
Like "P." africanus, "P." phiomensis is much more derived than the type species of Pterodon and thus requires a different genus name. Furthermore, analysis showed that it was not closely related to "P." africanum either. It is most closely allied with the clade formed by Akhnatenavus, Isohyaenodon and Hyainailouros.
P. sp.
Lower Sequence
Quarry E
A broken canine.
An isolated tooth similar in size to "P." phiomensis.
Originally named as a species of Apterodon alongside A. altidens, later research showed it clearly differed from this genus. It may instead be related to "Sinope" ethiopica.
S. markgrafi was initially named by Holroyd as a species of Metapterodon in 1999, but placed in the new genus Sectisodon by Morales and Pickford in 2017.
A hyaenodont originally described as a species of Sinopa, although later research clearly shows that it does not belong to the American-Asian genus. Its exact relation to other hyaenodonts remains uncertain until further study, however it has been suggested to be a relative of Quasiapterodon.
Holroyd also identified several indetermined pterodontine hyaenodonts from various sequences of the Jebel Qatrani Formation, but doesn't identify them beyond subfamily level.[30]
Mandibles, a crushed cranium as well as various incomplete skull fossils and postcranial elements.
A gazelle-like titanohyracine described in 2000. The teeth and limb bones indicate that it was a cursorial browser, similar to modern antelopes and gazelles.
Various skull remains including maxillary fragments and dentary remains.
It is the smallest species of Geniohyus, with the name originating when it was still considered a part of Saghatherium. Its dentition forms an intermediate between other Geniohyus and Bunohyrax.
Saghatherium had heavy jaws and possibly fed on nuts and seeds. Furthermore, members of this genus display pronounced sexual dimorphism and may have had complex mating rituals. The species S. sobrina was shown to simply represent female individuals of this species.
A hyracoid named for its selenodont teeth (molars with crescent-shaped ridges), which are much more developed than in Titanohyrax. These teeth indicate a diet that required it to slice vegetation rather than grind it. It is a small hyrax, only slightly larger than Saghatherium which it might have descended from.
Primarily mandibular remains and teeth, but also some limb elements and vertebrae.
Thyrohyrax is among the smaller hyracoids of Fayum and resembles today's arboreal Dendrohyrax. Species of Thyrohyrax display little size-related sexual dimorphism, however males do possess enlarged, tusk-like second incisors and chambered mandibles.
The front of a skull with an associated mandible as well as several teeth from another specimen.
A close relative of direct descendant of T. litholagus. It was originally assigned to Saghatherium magnum, then described as a species of Megalohyrax before being moved into Pachyhyrax and eventually Thyrohyrax.
Five specimens including two mandibles and a single maxilla.
Titanohyrax species are the largest hyracoids of the Fayum Depression and form the clade Titanohyracinae with Antilohyrax. Like their smaller relative, they are thought to have been folivores. The lower incisors of T. andrewsi were shaped like spatulas, rather than tusks.
Eight specimens including maxillary, premaxillary and mandibular remains.
T. angustidens has the most complex history among Titanohyrax species, initially assigned to Megalohyrax and given the name M. palaeotheroides, it was later recognized as Titanohyrax and variably considered distinct or synonymous with T. andrewsi. The name T. palaeotheroides was not retained as it was a nomen nudum.
The largest species of Titanohyrax, weight estimates for T. ultimus range from 600–1,300 kg (1,300–2,900 lb), making it possibly as large as the modern sumatran rhino.
Several specimens including a maxilla and three mandibles
A primitive marsupial and the basalmost mammal found in the sediments of the formation. It was at one point known under the name Qatranitherium, however this name has since then been deemed a junior synonym.
This species also includes several specimen previously assigned to Phiomys andrewsi. However, as it was not adequately described it is considered a nomen nudum.
A. bowni
Lower Sequence
Quarry L-41
Complete upper and lower dentition as well as parts of the lower jaw and the skull.
A basal member of Phiomorpha and the largest member of the family "Phiomyidae", although the group is now considered to be paraphyletic. It is the only species of Acritophiomys that had been validly named, as both A. adaios and A. woodi were only described in a thesis.
A. woodi
Lower Sequence
Quarry L-41
The first phiomydid described from the Quarry L-41. However, as it was not adequately described it is considered a nomen nudum.
The type species of the genus, described by Wood in the 1960s. It is intermediate in size among the Fayum rodents, larger than the small Phiocricetomys but smaller than Metaphiomys. Its phylogeny is enigmatic and it has variably been placed as a sister to old world porcupines or within Caviomorpha.
G. aslius
Lower Sequence
Quarry L-41
A distorted skull and various fragmentary remains.
It shows several primitive features and may resemble the ancestral form of this genus.
G. hylaeus
Lower Sequence
Quarry L-41
A flattened skull and various additional fragments.
G. hylaeus was initially named by Holroyd in a PhD Thesis, rendering it a nomen nudum until the full description authored by Sallam, Seiffert and Simons.
Initially thought to be a species of Phiomys, it was named Elwynomys in a doctoral dissertation from 1994. Due to the rules of the ICZN, the name Talahphiomys later took precedence.
The fragmentary remains of what may have been a pangolin. The presence of termite nests bearing excavation marks may support this, however the identity of these finger bones is not universally supported and has been questioned.
A ptolemaiid afrothere. Despite being from a younger animal, the material of Q. meyeri is larger than that of Ptolemaia lyonsi which is known from the same locality. Simons and Rasmussen suggest it may have been a racoon-like omnivore.[2]
A parapithecid primate known from a rich fossil record. Apidium phiomense is the type species and one of the first primates described from Jebel Qatrani.
A rarer species of oligopithecid. Members of this family are almost absent in the upper sequence of the formation, which may be a delayed result of climate change during the Eocene-Oligocene transition. The teeth of Oligopithecus indicate it may have been a frugivore.
A left hemimandible with alveoli for all teeth and a single, mostly complete molar tooth.
The smallest known oligopithecid and one of the smallest anthropoids. It is comparable in body mass to modern marmosets of the genus Callithrix and has been noted to be smaller than the fat-tailed dwarf lemur.
A disputed genus of proteopithecid primate. It was originally named as a species of Parapithecus, but later raised to its own genus. However, this is not universally accepted.
A small, possibly semi-aquatic proboscidean roughly the size of a tapir. M. trigodon has some features of its dentition that may suggest that it could be a genus distinct from Moeritherium. Another species was also named from the formation, M. andrewsi, but modern research has drastically cut down on the number of valid species, with most now being lumped into either the type species of M. trigodon.
An early proboscidean named by Andrews in 1901. It is the type species of the genus Palaeomastodon. Unlike Moeritherium, Palaeomastodon and Phiomia are considered to have been terrestrial animals.
P. minor
A species distinguished from P. beadnelli through its smaller size. The status of most Palaeomastodon species is complex and has been discussed repeatedly.
P. parvus
Another small species of Palaeomastodon.
P. wintoni
Although morphologically similar to P. minor it was slightly larger, but fails to approach the size of the type species. It is the most common species in the formation.
Although multiple species have been named in the past, Phiomia serridens is currently the only valid species of this genus native to Fayum. Species of Palaeomastodon were at times also assigned to Phiomia.
^ abcdGaffney, E.S.; Meylan, P.A.; Wood, R.C.; Simons, E.; de Almeida Campos, D. (2011). "Evolution of the side-necked turtles: the family Podocnemididae". Bulletin of the American Museum of Natural History. 350: 1–237. doi:10.1206/350.1. hdl:2246/6110. S2CID83775718.
^Pérez-García, A. (2017). "New information and establishment of a new genus for the Egyptian Paleogene turtle "Stereogenys" libyca (Podocnemididae, Erymnochelyinae)". Historical Biology. 31 (3): 1–10. doi:10.1080/08912963.2017.1374383. S2CID90915135.
^Sileem, A.H.; Sallam, H.M.; Hewaidy, A.G.A.; Miller, E.R.; Gunnell, G.F. (2016). "A new anthracothere (Artiodactyla) from the early Oligocene, Fayum, Egypt, and the mystery of African 'Rhagatherium' solved". Journal of Paleontology. 90 (1): 170–181. Bibcode:2016JPal...90..170S. doi:10.1017/jpa.2016.13. S2CID132618649.
^Patricia A. Holroyd, Fabrice Lihoreau, Gregg F. Gunnell und Ellen R. Miller: Anthracotheriidae. In: Lars Werdelin und William Joseph Sanders (Hrsg.): Cenozoic Mammals of Africa. University of California Press, Berkeley, Los Angeles, London, 2010, S. 843–851
^ abcGunnell, G. F.; Simons, E. L.; Seiffert, E. R. (2008). "New bats (Mammalia: Chiroptera) from the late Eocene and early Oligocene, Fayum Depression, Egypt". Journal of Vertebrate Paleontology. 28 (1): 1–11. doi:10.1671/0272-4634(2008)28[1:nbmcft]2.0.co;2. S2CID86125632.
^ abMorales, J.; Pickford, M. (2017). "New hyaenodonts (Ferae, Mammalia) from the early Miocene of Napak (Uganda), Koru (Kenya) and Grillental (Namibia)". Fossil Imprint. 73 (3–4): 332–359. doi:10.2478/if-2017-0019. hdl:10261/195968. S2CID31350436.
^De Blieux, D.D.; Simons, E.L. (2002). "Cranial and dental anatomy of Antilohyrax pectidens: a late Eocene hyracoid (Mammalia) from the Fayum, Egypt". Journal of Vertebrate Paleontology. 22 (1): 122–136. doi:10.1671/0272-4634(2002)022[0122:CADAOA]2.0.CO;2. S2CID87901588.
^ abMatsumoto, H. (1922). "Megalohyrax, Andrews and Titanohyrax, gen. nov. A revision of the genera of hyracoids from the Fayum, Egypt". Proceedings of the Zoological Society (1921): 839–850.
^ abcdRasmussen, D.T.; Simons, E.L. (1991). "The Oldest Egyptian Hyracoids (Mammalia: Pliohyracidae): New Species of Saghatherium and Thyrohyrax from the Fayum". Neues Jahrbuch für Geologie und Paläontologie. 182 (2): 187–209. doi:10.1127/njgpa/182/1991/187.
^ abcdefghiSeiffert, E. R.; Simons, E. L. (2013). "Last of the oligopithecids? A dwarf species from the youngest primate-bearing level of the Jebel Qatrani Formation, northern Egypt". Journal of Human Evolution. 64 (3): 211–215. doi:10.1016/j.jhevol.2012.10.011. PMID23416038.
^ abcdeSimons, E. L.; Seiffert, E. R.; Chatrath, P. S.; Attia, Y. (2001). "Earliest Record of a Parapithecid Anthropoid from the Jebel Qatrani Formation, Northern Egypt". Folia Primatologica. 72 (6): 316–331. doi:10.1159/000052748. PMID11964500. S2CID34259124.