Teilhardina belgica is one of the earliest fossil primates ever recovered and the oldest fossil primate from Europe (~ 56 Million years). It was originally described by Teilhard de Chardin (1927) from the MP7 reference level of Dormaal (Belgium), which is situated at the Paleocene-Eocene boundary at the base of the Tienen Formation (Smith & Smith, 1996). Teilhardina is known on all three northern continents in association with the carbon isotope excursion marking the Paleocene–Eocene Thermal Maximum. Relative position within the carbon isotope excursion indicates that Asian Teilhardina asiatica is oldest, European T. belgica is younger, and North American T. brandti and T. americana are, successively, youngest. Analysis of morphological dental characteristics of all four species supports an Asian origin and a westward Asia-to-Europe-to-North America dispersal for Teilhardina. High-resolution isotope stratigraphy indicates that this dispersal happened in an interval of 25,000 years (Smith et al, 2006). Moreover, Teilhardina is one of the most primitive fossil primates known to date and the earliest haplorhine with associated three dimensional postcranials making it relevant to a reconstruction of the ancestral primate morphotype. As such, Teilhardina has often been hypothesized as a basal tarsiiform on the basis of its primitive dental formula with four premolars and a simplified molar cusp pattern. Until recently, little was known concerning its postcranial anatomy with the exception of its well-known tarsals. Here we describe additional postcranial elements for Teilhardina belgica and compare these to other tarsiiforms and to primitive adapiforms. Teilhardina is a small primate with an estimated body mass between 30-60 g, similar to the size of a mouse lemur. Its hindlimb anatomy suggests frequent and forceful leaping with excellent foot mobility and grasping capabilities. It can now be established that it exhibits critical primate postcranial synapomorphies such as a grasping hallux and a tall knee (Gebo et al, 2012), and nailed digits (Rose et al, 2011). This anatomical pattern and behavioral profile is similar to what has been inferred before for other omomyids and adapiforms. The most unusual feature of Teilhardina belgica is its elongated middle phalanges suggesting that this early primate had very long fingers similar to those of living tarsiers. Our phyletic analysis indicates that we can identify several postcranial characteristics shared in common for stem primates as well as note several derived postcranial characters for Tarsiiformes.
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