Suminia getmanovi: First Arboreal Vertebrates With Grasping Hands and Opposable Thumbs Lived 260 Million Years Ago

The skeleton of the tree-climbing synapsid Suminia getmanov, a 260-million-year-old animal which scientists believe was the first known tree-dweller. The tiny, agile animal predated the arrival of the dinosaurs.

The Department of Geology, Field Museum Public Relations, Chicago on July 28, 2009, released the following press release: "In the Late Paleozoic (260 million years ago), long before dinosaurs dominated the Earth, ancient precursors to mammals took to the trees to feed on leaves and live high above predators that prowled the land, Jörg Fröbisch, PhD, a Field Museum paleontologist has concluded. Elongated fingers, an opposable "thumb," and a grasping tail of Suminia getmanovi demonstrate that this small plant-eating synapsid is the earliest known tree-climbing vertebrate.

"Suminia was relatively small, about 20 inches from its nose to the tip of its tail. The tree-climbing lifestyle of this Paleozoic relative of mammals is particularly important because for the first time in vertebrate evolution it gives access to new food resources high off the ground, and also provides protection from ground-dwelling predators. The evidence for this lifestyle is based on several excellent skulls and more than a dozen exceptionally well preserved, complete skeletons from a single large block of red mudstone that was discovered in central Russia's Kirov region.

"Having so many individual specimens, some of mature individuals and some of youngsters, was helpful in providing a complete picture of the animal's skeletal anatomy, said Fröbisch. "It's relatively rare to find several animals locked on a single block," he said. "We have examples of virtually every bone in their bodies."

"Finding that vertebrates took to trees so early in Earth's evolution was unexpected. "It's a surprise, but it makes sense," Fröbisch said. "It was a new niche for vertebrates. There was food available and they avoided predators on the ground."

"The study also provides the first evidence in the fossil record of food partitioning between small climbing and large ground-dwelling plant-eaters and this happens shortly after the establishment of the modern terrestrial ecosystem with large numbers of plant-eaters supporting few top predators. Earlier terrestrial vertebrate communities did not have this modern hierarchy, but instead were composed of various-sized predators and relatively few plant-eaters, with most of the food resources being provided by insects and aquatic organisms."

Fleshed-out and skeletal restorations of Suminia. From Frobisch and Reisz (2009)

"As the first tree-climbing vertebrate, Suminia had very long fore and hind limbs, with especially long hands and feet," lead author Jorg Frobisch said. Frobisch continued: "In particular, its long fingers, or digits, contributed to these large hands and feet," ... It further had long, strongly-curved claws — terminal phalanges — that helped with clinging onto tree trunks and branches... Non-mammalian synapsids were formerly unofficially known as 'mammal-like reptiles,' but they are actually not at all reptiles, but are more closely related to mammals," Frobisch said, adding that Suminia indeed "is a distant relative of mammals."

Frobisch explained that before the first known tree-dweller emerged, "terrestrial vertebrate communities were composed of various-sized predators and relatively few plant-eaters, with most of the food resources being provided by insects and aquatic organisms."

"So this shift in what food is eaten all of a sudden increases competition for plant food resources, and shortly after this shift, you see Suminia invade this ecological space for the first time," he added.

The hand of Suminia (right) compared to terrestrial anomodonts (mostly toothless herbivores) Galechirus (middle) and Robertia (left). Note the claw-like finger bones and divergent "thumb" of Suminia. From Frobisch and Reisz (2009)

Brian Switeka science writer who focuses on paleontology, evolution, and the history of science provided the following assessment: "The hands of Suminia widely differed from those of terrestrial anomodonts and more closely resembled those of other arboreal vertebrates from various groups and time periods. It appeared that lineages that adopted an arboreal lifestyle evolved similar traits over and over again, these similarities being due to convergent evolution. Comparisons between Suminia and living arboreal vertebrates supported this hypothesis, and Frobisch and Reisz make a very well-supported case that Suminia moved through the trees by clinging and grasping.

Switeka continued: "Why the ancestors of Suminia moved into the trees, however, is another question. The Permian deposits in which Suminia was found is relatively well-sampled. During the time the little synapsid was skittering through the trees the local environment supported a large number of herbivores (about 83% of all the vertebrates present) and a much smaller number of carnivores (about 13% of all the vertebrates present). While it is true that an arboreal lifestyle may have helped keep Suminia out of the jaws of predators, the authors hypothesize that it was competition with other herbivores that might have driven some synapsids into the trees. These plants would have been a resource unexploited by other vertebrates, and this may have allowed for the evolution of Suminia from more terrestrially-adapted ancestors."

Suminia getmanovi

Missing Link: A Transitional Species Between Ancient Mammals and Primates Thought to be Found in Fossil of "Ida"

The beautifully preserved remains of a 47-million-year-old, lemur-like creature have been unveiled in the US.

"Scientists have unveiled a 47-million-year-old fossilised skeleton of a monkey hailed as the missing link in human evolution.

"The search for a direct connection between humans and the rest of the animal kingdom has taken 200 years - but it was presented to the world today at a special news conference in New York.

"The discovery of the 95%-complete 'lemur monkey' - dubbed Ida - is described by experts as the "eighth wonder of the world"

"The preservation is so good, it is possible to see the outline of its fur and even traces of its last meal.



"The fossil, nicknamed Ida, is claimed to be a "missing link" between today's higher primates - monkeys, apes and humans - and more distant relatives.

"But some independent experts, awaiting an opportunity to see the new fossil, are sceptical of the claim.

"And they have been critical of the hype surrounding the presentation of Ida.

"The fossil was launched amid great fanfare at the American Museum of Natural History in New York, by the city's mayor.

"Although details of the fossil have only just been published in a scientific journal - PLoS One - there is already a TV documentary and book tie-in.

"She belongs to the group from which higher primates and human beings developed but my impression is she is not on the direct line." Dr Jens Franzen conjectured.

"Ida was discovered in the 1980s in a fossil treasure-trove called Messel Pit, near Darmstadt in Germany. For much of the intervening period, it has been in a private collection.

"The investigation of the fossil's significance was led by Jorn Hurum of the Natural History Museum in Oslo, Norway.



"He said the fossil creature was "the closest thing we can get to a direct ancestor" and described the discovery as "a dream come true".

"The female animal lived during an epoch in Earth history known as the Eocene, which was crucial for the development of early primates - and at first glance, Ida resembles a lemur.

"But the creature lacks primitive features such as a so-called "toothcomb", a specialised feature in which the lower incisor and canine teeth are elongated, crowded together and projecting forward. She also lacks a special claw used for grooming.

"The team concluded that she was not simply another lemur, but a new species. They have called her Darwinius masillae, to celebrate her place of origin and the bicentenary of the birth of Charles Darwin.

"Dr Jens Franzen, an expert on the Messel Pit and a member of the team, described Ida as "like the Eighth Wonder of the World", because of the extraordinary completeness of the skeleton.

"It was information "palaeontologists can normally only dream of", he said.

"In addition, Ida bears "a close resemblance to ourselves" he said, with nails instead of claws, a grasping hand and an opposable thumb - like humans and some other primates. But he said some aspects of the teeth indicate she is not a direct ancestor - more of an "aunt" than a "grandmother".

"She belongs to the group from which higher primates and human beings developed but my impression is she is not on the direct line."

Independent experts are keen to see the new fossil but somewhat sceptical of any claim that it could be "a missing link".

Dr Henry Gee, a senior editor at the journal Nature, said the term itself was misleading and that the scientific community would need to evaluate its significance.

"It's extremely nice to have a new find and it will be well-studied," he said. But he added that it was not likely to be in the same league as major discoveries such as "Flores man" or feathered dinosaurs.

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"Dr Chris Beard, curator of the Carnegie Museum of Natural History and author of The Hunt for the Dawn Monkey, said he was "awestruck" by the publicity machine surrounding the new fossil.

"He argued that it could damage the popularisation of science if the creature was not all that it was hyped up to be.

"Dr Beard has not yet seen scientific details of the find but said that it would be very nice to have a beautiful new fossil from the Eocene and that Ida would be "a welcome new addition" to the world of early primates.

"But he added: "I would be absolutely dumbfounded if it turns out to be a potential ancestor to humans."

"In the PLoS paper itself, the scientists do not actually claim the specimen represents a direct ancestor to us. But Dr Hurum believes that is exactly what Ida is.

"He told BBC News that the key to proving this lay in the detail of the foot. The shape of a bone in the foot called the talus looks "almost anthropoid".

"He said the team was now planning a 3D reconstruction of the foot which would prove this.

"We're not finished with this specimen yet," said Dr Hurum. "There will be plenty more papers coming out."