Complete Primate Skeleton from the Middle Eocene of Messel in Germany: Morphology and Paleobiology

Abstract

BackgroundThe best European locality for complete Eocene mammal skeletons is Grube Messel, near Darmstadt, Germany. Although the site was surrounded by a para-tropical rain forest in the Eocene, primates are remarkably rare there, and only eight fragmentary specimens were known until now. Messel has now yielded a full primate skeleton. The specimen has an unusual history: it was privately collected and sold in two parts, with only the lesser part previously known. The second part, which has just come to light, shows the skeleton to be the most complete primate known in the fossil record.Methodology/Principal FindingsWe describe the morphology and investigate the paleobiology of the skeleton. The specimen is described as Darwinius masillae n.gen. n.sp. belonging to the Cercamoniinae. Because the skeleton is lightly crushed and bones cannot be handled individually, imaging studies are of particular importance. Skull radiography shows a host of teeth developing within the juvenile face. Investigation of growth and proportion suggest that the individual was a weaned and independent-feeding female that died in her first year of life, and might have attained a body weight of 650–900 g had she lived to adulthood. She was an agile, nail-bearing, generalized arboreal quadruped living above the floor of the Messel rain forest.Conclusions/Significance Darwinius masillae represents the most complete fossil primate ever found, including both skeleton, soft body outline and contents of the digestive tract. Study of all these features allows a fairly complete reconstruction of life history, locomotion, and diet. Any future study of Eocene-Oligocene primates should benefit from information preserved in the Darwinius holotype. Of particular importance to phylogenetic studies, the absence of a toilet claw and a toothcomb demonstrates that Darwinius masillae is not simply a fossil lemur, but part of a larger group of primates, Adapoidea, representative of the early haplorhine diversification.

Evolution and the Media

“…At the American Museum of Natural History, New York City Mayor Michael Bloomberg and other luminaries gazed at the slab preserving a 47-million-year-old specimen (known as Ida, named after the daughter of one of the paleontologists who described the fossil). Minutes before the press conference commenced, the journal PLOS One electronically published a paper about the fossil (Franzen et al 2009). Some of the paper's authors, speaking at the press conference, described the fossil as the Holy Grail of paleontology and the lost ark of archeology.…”

Ancestor or Adapiform? Darwinius and the Search for Our Early Primate Ancestors

“…1 Slab a (to the left) and slab b (to the right; dashed outlines enclose authentic skeletal material) of the Eocene fossil primate D. masillae (from Franzen et al 2009b) the rock as seas retreated, climates changed, and organisms evolved and slipped into extinction over tens of millions of years. Then in 1875, members of our relatively young species began finding fossils from the Messel site.…”

“…Despite these findings, however, there was no major effort to start scientific study of the site until the latter part of the twentieth century, but just as soon as the research started it seemed as if it might be halted forever. As of 1975, plans were put in action to turn the defunct oil shale quarry into a garbage dump, and both scientists and amateur collectors began to take what they could from the site (Franzen 1985(Franzen , 2010Franzen et al 2009a).…”

“…During preparation, however, the main slab was used as a guide to fabricate the missing parts of the lesser slab, and in 1991 the partially forged slab was sold to the Wyoming Dinosaur Center. It is a testament to the workmanship of the unknown preparatory team that the partially fabricated nature of the specimen was not discovered until after the purchase had been made (Franzen et al 2009a). It was not then apparent that it represented a new genus of fossil primate different from those previously discovered at Messel.…”

Saving our science from ourselves: the plight of biological classification

“…Public perception of taxonomy and systematics differs remarkably from that of science funding bodies and end-users of taxonomic data, as shown by the recent discovery of Ida, the lemur-like primate Darwinius masillae (Franzen et al 2009). The discovery of this wonderfully well-preserved fossil from Messel, Germany, and the possibility that it represents a "missing link" between primates and humans took the public by storm.…”