Darwinius masillae – Missing Link Debate Hots Up

Earlier this year, a paper published on the discovery of an ancient primate fossil from the Messel shales, a World Heritage site in Germany, attracted a great deal of publicity.  It was heralded as an important discovery, the earliest example of a primate whose descendants were to become the higher apes and eventually the hominids.  The species was named Darwininus masillae.

To read an article on the discovery of D. masillae: The Relationship between Hominids and Lemurs – Darwinius.

Darwinius masillae

The 47-million-year-old fossil, regarded as “humanity’s long lost ancestor” and publicised as “the first link in human evolution”, was unveiled earlier this year.  The fossil was nicknamed “Ida” by Dr Jorn Hurum, the scientist who revealed the fossil to the world, Ida is the name of the doctor’s daughter.  However, other scientists have refuted the claim that this fossil represents an early ancestor of the line of apes that were to lead to humans.

There was even a documentary on the discovery narrated by Sir David Attenborough and shown at peak viewing time on the BBC.  Dr Hurum and his team identified “Ida” as having lived at around the time the primates were splitting into two distinct branches, the Haplorhines, which includes the apes and a second group which includes the lemurs, lorises and pottos (Strepsirrhines).

Lemur-like Characteristics

Darwinius excited palaeontologists as this fossil lacked lemur-like characteristics, no fused teeth in the middle of the lower jaw and no grooming claw, suggesting that this material represented the newly developing “human branch” of primates.  Dr Hurum reported this fossil as being the “first link in human evolution”, guaranteeing a great deal of media interest.

However, the significance of “Ida” is being called into doubt by a paper that will be published in the scientific magazine “Nature”.  A team of scientists, led by D. Erik Seiffert from Stony Brook University in New York, examined another primate fossil, a 37-million-year-old fossil very closely related to “Ida”.  Dr Seiffert and his team have stated that both mammals belong to a group called the Adapoids, extinct primates that are believed not to be related to Hominids.

Dr Seiffert stated:

“Phylogenetic analysis of over 300 characteristics across 117 living and extinct primates reveals that the Adapoids are not ancestors to higher primates but rather a separate lineage with no known descendants”.

He went on to add:

“This means that the features they share with higher primates, such as the loss of the upper and lower second premolar, must have evolved independently.”

Some Examples of Messel Shale Fossils

The atmospheric Messel gallery at the Senckenberg Museum (Frankfurt). Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

This new paper is a little embarrassing considering the amount of publicity the unveiling of Darwinius generated.  It questions the main findings of the earlier discovery.  It seems that the importance of the Darwinius fossil will be debated for many years to come.

Visit Everything Dinosaur’s website for prehistoric animal figures: Prehistoric Animal Figures.

Fruitadens haagarorum – Tiniest Dinosaur known to Science

Thirty years after its fossils were discovered in Colorado, a new genus of ornithischian dinosaur has been named and described, perhaps the smallest dinosaur discovered to date.  In a paper published in the scientific journal “Royal Society Journal Proceedings B (Biology)”, the research team claim that this little dinosaur weighed less than a kilogramme.  This puts the tiny Fruitadens haagarorum in pole position when it comes to identifying the smallest species of dinosaur discovered to date.  Other contenders include the feathered Microraptor gui from the Liaoning Province of north-east China.

Microraptor is estimated to have measured something like 40-60 centimetres.  The diminutive Micropachycephalosaurus, also from China was of a similar size, although the exact taxonomic classification of this Late Cretaceous ornithischian remains uncertain (incertae sedis).

Ornithischian Dinosaur

There were certainly many small theropods but for the moment it is Fruitadens haagarorum that is taking the plaudits for being the smallest dinosaur known from the fossil record,  with a body weight no more than two bags of sugar.

Classifying Dinosaurs

Classifying dinosaurs by the shape of their hip bones.

Pictures show an artist’s impression of Fruitadens haagarorum in comparison with an adult human.   The fossils had been housed at the Natural History Museum of Los Angeles County, since they were discovered in Colorado in 1979.  The partial remains of at least four individuals including skull material are known and it is believed that this animal was a a member of the Heterodontosauridae, a primitive group of ornithopods.

The fossils were found in sandstones dating from the Late Jurassic (Tithonian faunal stage), approximately 150 million years ago.  The sandstones are part of the famous Morrison Formation of rocks from the Upper Jurassic which have yielded a large number of famous dinosaurs such as Apatosaurus, Diplodocus, Allosaurus and Stegosaurus.

The study into this tiny, fleet footed dinosaur was led by Richard Butler from the Bavarian State Collection for Palaeontology in Munich, southern Germany.  Analysis of the teeth in the minute jaw indicate that this ornithischian may have been an omnivore.  Most ornithischians are totally herbivorous but this agile little dinosaur may have eaten a variety of food stuffs, plant material, insects and perhaps small mammals, amphibians and lizards.

Fruitadens haagarorum

Photographs show a tiny fragment of lower jaw with dentition (teeth) of the minute dinosaur Fruitadens.

Commenting on the prospect of an ornithischian dinosaur being an omnivore, Richard Butler stated:

“This is unusual for that group [Ornithischia] most of them were strict herbivores.  But if you’re small, it is hard to feed on just vegetation, as it is difficult to digest”.

Bigger animals with much larger guts were better able to survive on a plant-only diet.  Larger animals have bigger guts, and a big gut is what you need to help digest tough plant material.  The genus name refers to an area of Colorado called Fruita, where the fossils were first discovered.  The specific name is in honour of the Haaga family who have long been supporters of the Natural History Museum of Los Angeles County.

Dr Butler went onto add:

“Fruitadens, comes from a series of rocks, the Morrison Formation, which palaeontologists have studied intensively for 130 years, and from which dozens of dinosaur species are already known.  Yet it is still possible to discover completely unique and remarkable species.  If dinosaur ecosystems were that diverse, who knows what astonishing beasts are waiting for us to discover”?

This little dinosaur probably scampered around the undergrowth, avoiding predators such as Ornitholestes, using its speed to keep itself out of trouble.  Ironically, some of the contemporaries of Fruitadens, the sauropods were so large that this little dinosaur could have run around these leviathans without them noticing.

Everything Dinosaur stocks a huge range of models of ornithischian dinosaurs to view this range: Everything Dinosaur – Prehistoric Animal Models and Figures.