Thursday, January 7, 2010

Oldest Anthropoid Fossil Hails From Thailand, Said Thai Officials

So supposedly a newly publicized paper back in November 2009 confirms that the oldest primate anthropoid fossil comes from the southern province of Krabi, Thailand (according to some Thai news articles, which unfortunately I cannot find where they cited their primary sources). It was discovered 14 years ago by Thailand's Mineral Resources Department archaeologists. Siamopithecus eocaenus supposedly roamed the earth 35 million years ago and is in fact currently the oldest primate anthropoid fossil from the fossil record (again, can't find where they cited the primary source). Thanks to Mae Kai Fa for pointing out that it is the oldest "anthropoid" fossil not primate fossil, which makes more sense.

Siamopithecus eocaenus or the Siam Ape gets its name from the country it was found. Siam was the official name of Thailand until 1939, although it is still somewhat used synonymously with Thailand.

Fragments of the fossil includes the lower right molars and upper left and right molars that are attached to the eye bone. Researchers think that S. eocaenus is about the size of a gibbon, weighs around 7kg and belongs to the Amphipithecidae family.

So, I don't know. This sounds a bit like the Darwinius massilae fiasco all over again. I also wonder why no one picked up this news, except a sprinkle of Thai news websites. What do you think? The paper pointed out by these articles is possibly The Face of Siamopithecus: New Geometric-Morphometric Evidence for Its Anthropoid Status by Zollikoffer et al. (2009) that was published in The Anatomical Record on November. Unfortunately I do not have access to that journal so I can't verify whether the paper did point out that S. eocaenus is indeed 35 million years ago.

Some Thai news article:
Oldest primate fossils found by Bangkok Post.
35-mn-year-old fossil raises questions on primates' origin by
Oldest primate fossils found in Krabi by National News Bureau of Thailand (NNT).


Mae Kai Fa said...

Hi. I live in Thailand and found my way here after reading the Bangkok Post's version of the Anatomy Record article.

This is from the home page of Christoph P.E. Zollikofer. The primary author of the article. It claims an age of 40 million years for the formation the fossil was found in and says the "oldest anthropoid fossil" rather than the "oldest primate fossil", which is a far more sensible claim.

Siamopithecus: the first anthropoid

The fragmentary maxillofacial and mandibular remains of a Siamopithecus specimen from the Late Eocene Krabi formation, Thailand (approximately 40 million years ago) plays a key role in the investigation of early anthropoid evolution from lemuroid stem groups. Computer-assisted reconstruction of the deformed and compressed remains revealed a series of anthropoid features that is currently being checked against an extended sample of fossil and extant prosimian and simian specimens. Geometric-morphometric analysis focuses on quantitative features characterizing taxon-specific relationships between mandibular, maxillar and orbital morphology in prosimians and simians. This project is carried out in cooperation with Yaowalak Chaimanee (Geological Survey, Bangkok) and J.-J. Jaeger (University of Montpellier II).

Raymond Ho, FCD said...

Hi Mae Kai Fa. Thanks for the comment.

Yes, I think the anthropoid claim is far more sensible than the "primate" claim and would make much more sense. Thanks for the clarification!