Hindlimb of a giant terrestrial bird from the upper Eocene, Fayum, Egypt

Abstract

ABSTRACT. Eremopezus eocaenus Andrews, 1904 is a giant groundbird from upper Eocene deposits of the Fayum, Egypt, which has hitherto been known from non-diagnostic fragmentary material. New fossils collected from quarry L-41 of the Jebel Qatrani Formation include two well-preserved distal tarsometatarsi and an associated whole tarsometatarsus and distal tibiotarsus that allow a more precise evaluation of the phylogenetic position and tarsal function of Eremopezus. Unlike most ratites, the distal tarsometatarsus has a patent distal foramen and a slight hallucal digit. The trochlea for digits II and IV are only slightly reduced in size, are splayed to the right, and the heads lack deep grooving. These features resemble the condition seen in Balaeniceps and Sagittarius, suggesting active use of the toes in grasping or manipulation, rather than the condition in graviports and cursors, which have reduced medial and lateral trochleae often with distinct grooving of the heads. The limb is relatively long and gracile, another difference from graviports. There is no compelling evidence to link Eremopezus to any known ratite lineage, to the Phorusrhacoidea, or to the extinct predatory birds of the Eocene (e.g. Diatryma, Gastornis). We suggest that Eremopezus represents an endemic African group that independently attained large size and¯ightlessness.

Late Eocene and early Oligocene teleost and associated ichthyofauna of the Jebel Qatrani Formation, Fayum, Egypt

“…Based on the living relatives of the Jebel Qatrani teleosts, the palaeoenvironment represented by these deposits probably included open waters and deep rivers, along with abundant vegetation. The teleost ®shes from the Jebel Qatrani indicate the same type of environment as has previously been proposed based on the bird assemblage (Rasmussen et al 1987). The fossil birds are related to modern forms that prefer waters with slow currents and lentic conditions with emergent aquatic vegetation, swampy areas, or extensive over-bank areas (Rasmussen et al 1987).…”

“…The teleost ®shes from the Jebel Qatrani indicate the same type of environment as has previously been proposed based on the bird assemblage (Rasmussen et al 1987). The fossil birds are related to modern forms that prefer waters with slow currents and lentic conditions with emergent aquatic vegetation, swampy areas, or extensive over-bank areas (Rasmussen et al 1987). Wing and Tiffney (1982) have suggested that in Oligocene times, the Fayum contained a shallow swampy river, or series of rivers, overgrown in places with papyrus, reeds and¯oating vegetation such as Salvinia and water lilies.…”

“…Rasmussen et al (2001) noted that the formation consists mainly of sandstones and mudstones deposited as river bars and overbank sediment, and suggested that the formation accumulated as part of an aggrading system of river channels, which¯owed primarily westward into a basin south of the Tethys Sea shoreline. Their studies led to the reconstruction of the depositional environment as a lowland area of tropical swamp forests, marshes and meandering rivers that probably had a monsoonal climate (Rasmussen et al 2001).The ®sh material discussed in this paper comes from several different sites (Text-®g. 1) in the formation, which is separated by the Barite Sandstone into upper and lower parts.…”

“…The Jebel Qatrani Formation is capped by the Widan el Faras basalt, which has been dated radiometrically between 24´7 6 0´4±31´0 6 1´0 Ma (Gingerich 1992), but Kappleman et al (1992) suggested that 23´64 6 0´035 Ma is an appropriate date. One of the oldest sites, L-41, consists of ®ne mudstones and claystones with abundant evaporites (Rasmussen et al 2001), which have produced remains of lung®sh, cat®sh, characiforms, and channid ®shes, as well as remains of frogs and mammals. This site has been interpreted as a sizeable freshwater lake with evidence of current action (DeBlieux and Simons 2002).…”

A new method for estimating locomotion type in large ground birds

“…However, among the sub‐fossil birds that went extinct very recently, Aepyornithidae are considered to be graviportal (Amadon ; Rasmussen et al . ; Murray and Vickers‐Rich ) and can therefore serve for comparison.…”