Jebel Qatrani Formation

Heinrich Harder's reconstruction of Arsinoitherium zitteli in the Oligocene grassland of Jebel Qatrani escarpment.

The Jebel Qatrani Formation is a palaeontological and geologic formation located in the Faiyum Governorate of central Egypt.

Conformably overlying the Qasr el Sagha Formation. It is exposed namely between the Jebel Qatrani escarpment and the Qasr el Sagha escarpment, north of Birket Qarun lake near Faiyum.

Geology

These rocks were laid down in the Eocene-Oligocene period (Priabonian - Rupelian). This formation was originally thought to be between 35.4 and 33.3 million years old, based on initial analysis of the formation. However, analysis by Erik Seiffert in 2006 concluded that the age of the Jebel Qatrani Formation should be revised. His assessment of more recent evidence indicates an age for most of the formation of between 30.2 and 29.5 million years ago, placing it almost entirely in the Early Oligocene. Seiffert states that only the lowest 48 metres was laid down in the Eocene,^[1] but recent opinion holds the original hypothesis of a sediment straddling the Eocene-Oligocene boundary to be correct.

Mostly sandstones deposited by meandering rivers and seasonal lakes, the lower (Eocene) part of the formation represents a woodlanded ecosystem of which lots of petrified wood also remain. In contrast, the upper (Oligocene) layers present indication of much drier and cooler conditions, with savanna replacing the woodland for several million years before the climate turned wetter and warmer again and the forests regrew.

The fauna changes also notably during this time, which seems to be coincident with the Eocene–Oligocene extinction event recorded in Eurasia.

Fossils

Life restoration of prehistoric primate Aegyptopithecus zeuxis.

Reconstruction of Jebel Qatrani swamp forest at the end of the Eocene, with two Bothriogenys fraasi in front of an Arsinoitherium zitteli

Mammals

Arsinoitherium zitteli, an arsinoitheriid
Bothriogenys fraasi, an anthracotheriid
Herodotius pattersoni, a pseudoungulate
Plesiopithecus, an enigmatic lemur-like primate
Pliohyracidae, large hyraxes
Ptolemaiida, carnivorous afrothere mammals
Qatranilestes and Widanelfarasia, relatives of golden moles, otter shrews, and tenrecs
Several hyaenodontids (Akhnatenavus cf. leptognathus, Metapterodon)
Several hystricognath rodents (e.g. Acritophiomys bowni, A. woodi, Elwynomys lavocati, Gaudeamus hylaeus)
A primitive marsupial, maybe related to Peratherium
Primitive Old World monkeys (e.g. Aegyptopithecus zeuxis, Biretia fayumensis & B. megalopsis)

Birds

Eremopezus, an enigmatic large groundbird
Goliathia, a large shoebill relative
Palaeoephippiorhynchus dietrichi, a large stork
Xenerodiops, an unusual heron
A cormorant-like bird, possibly related to genus Piscator
Several jacanas
One or two species of primitive osprey and another bird of prey (possibly an ancestral sea eagle)
A turaco

Other animals

Albertwoodemys, a side-necked turtle
"Crocodylus" megarhinus, an ancestral crocodile
Eogavialis africanum, a primitive gharial
Parachanna fayumensis, a snakehead fish
Pterosphenus, a snake
African tetras (Alestidae) or similar Characiformes
Catfish, perhaps of genus Fajumia

References

↑ Seiffert Erik R. (Jan 2006). "Revised age estimates for the later Paleogene mammal faunas of Egypt and Oman". Proceedings of the National Academy of Sciences of the United States of America. 103 (13): 5000–5005. doi:10.1073/pnas.0600689103. PMC 1458784.

Vickers-Rich, Patricia & Rich, Thomas Hewett (1993); Wildlife of Gondwana. Reed. ISBN 0-7301-0315-3

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[Seiffert-1] Seiffert Erik R. (Jan 2006). "Revised age estimates for the later Paleogene mammal faunas of Egypt and Oman". Proceedings of the National Academy of Sciences of the United States of America. 103 (13): 5000–5005. doi:10.1073/pnas.0600689103. PMC 1458784.