New advance on crown formation time of anterior teeth of fossil orangutan from South China

Jan 03, 2013
Perikymata of a lower canine of fossil orangutan from South China.

Perikymata are typical enamel growth markings of anterior teeth, and their spacing pattern and total counts can provide helpful information on dental development and life history. Recently, researchers from Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) studied the perikymata spacing pattern and counts of anterior teeth of fossil orangutans from South China and published their study in recent Vertebrata PalAsiatica (issue 4, volume 32).

Lingxia Zhao and Rong Hu observed and analyzed perikymata spacing pattern and counts of anterior teeth of fossil orangutans by . By dividing tooth crown into three equal parts: cuspal, middle and cervical, the density of perikymata in cuspal third is lower than 10/mm, and there is no significant difference between the middle and cervical third, counting about 10-15/mm. Total numbers of perikymata counts are more in the upper central incisor than in the upper lateral incisor, more in canines than in incisors, and more in male canines than in female canines.

Referring to the cuspal enamel formation time of anterior teeth in extant apes, Lingxia Zhao and Rong Hu estimated that these formation times in incisors and canines of fossil orangutans were 0.5 year and 1.0 year, respectively. Lateral enamel formation time equals perikymata counts multiplied by nine-day periodicity of the Retzius line (which is very popular in our section analysis on molars). According to cuspal and lateral enamel formation times, they estimated that the incisor crown formation time was about 2.97-6.66 years. Canine crown formation times of male orangutans from were longer than that of females, and estimated between 6.25-11.31 years and 4.28-7.29 years, respectively.

"Compared with some fossil large apes, and Paranthropus, early Homo, Homo sapiens and extant apes, perikymata spacing of anterior teeth of from South China is more dense than that of Australopithecus and Paranthropus, and less than that of African apes, Homo sapiens and Lufengpithecus lufengensis", said Zhao. Except for the upper lateral incisor, perikymata counts of anterior teeth of fossil orangutan are similar to extant great apes, and greater than Australopithecus, Paranthropus, and early Homo. Crown formation times of these orangutan teeth was much longer than Proconsul, Australopithecus and Paranthropus, and closer to extant African apes, Lufengpithecus lufengensis and modern orangutan, especially.

Explore further: Egypt archaeologists find ancient writer's tomb

add to favorites email to friend print save as pdf

Related Stories

Humans related to orangutans, not chimps

Jun 18, 2009

New evidence underscores the theory of human origin that suggests humans most likely share a common ancestor with orangutans, according to research from the University of Pittsburgh and the Buffalo Museum of ...

Recommended for you

Egypt archaeologists find ancient writer's tomb

Apr 19, 2014

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Crowd-sourcing Britain's Bronze Age

Apr 17, 2014

A new joint project by the British Museum and the UCL Institute of Archaeology is seeking online contributions from members of the public to enhance a major British Bronze Age archive and artefact collection.

Roman dig 'transforms understanding' of ancient port

Apr 17, 2014

(Phys.org) —Researchers from the universities of Cambridge and Southampton have discovered a new section of the boundary wall of the ancient Roman port of Ostia, proving the city was much larger than previously ...

User comments : 0

More news stories

Clippers and coiners in 16th-century England

In 2017 a new £1 coin will appear in our pockets with a design extremely difficult to forge. In the mid-16th century, Elizabeth I's government came up with a series of measures to deter "divers evil persons" ...

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.