A "cerebral rubicon" in paleontology is the minimum

cranial capacity The size of the brain is a frequent topic of study within the fields of anatomy, biological anthropology, animal science and evolution. Measuring brain size and cranial capacity is relevant both to humans and other animals, and can be done by wei ...

required for a specimen to be classified as a certain paleospecies or genus. The term is mostly used in reference to human evolution. The Scottish anthropologist Sir

Arthur Keith Sir Arthur Keith FRS FRAI (5 February 1866 – 7 January 1955) was a British anatomist and anthropologist, and a proponent of scientific racism. He was a fellow and later the Hunterian Professor and conservator of the Hunterian Museum of the ...

set the limit at 750 cc for the genus ''Homo''. The minimum cranial capacity for the species

Homo sapiens Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

is generally set at 900cc. One of the reasons for the proposal to exclude ''

Homo habilis ''Homo habilis'' ( 'handy man') is an extinct species of archaic human from the Early Pleistocene of East and South Africa about 2.4 million years ago to 1.65 million years ago ( mya). Upon species description in 1964, ''H. habilis'' was highly ...

'' from the genus ''Homo'', and renaming it as "''Australopithecus habilis''", is the small capacity of their cranium (363cc -600 cc).

Origin

The term is most likely a reference to the

Rubicon The Rubicon (; ; ) is a shallow river in northeastern Italy, just south of Cesena and north of Rimini. It was known as ''Fiumicino'' until 1933, when it was identified with the ancient river Rubicon, crossed by Julius Caesar in 49 BC. The ri ...

river, which in the time of the

Roman Empire The Roman Empire ruled the Mediterranean and much of Europe, Western Asia and North Africa. The Roman people, Romans conquered most of this during the Roman Republic, Republic, and it was ruled by emperors following Octavian's assumption of ...

marked the border between

Cisalpine Gaul Cisalpine Gaul (, also called ''Gallia Citerior'' or ''Gallia Togata'') was the name given, especially during the 4th and 3rd centuries BC, to a region of land inhabited by Celts (Gauls), corresponding to what is now most of northern Italy. Afte ...

and Italy proper. Crossing the river with an army, as

Julius Caesar Gaius Julius Caesar (12 or 13 July 100 BC – 15 March 44 BC) was a Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey in Caesar's civil wa ...

did in 49 B.C., was illegal by Roman law and is commonly seen as the "point-of-no-return" for Caesar's revolution. As such, a "rubicon" can be used

idiom An idiom is a phrase or expression that largely or exclusively carries a Literal and figurative language, figurative or non-literal meaning (linguistic), meaning, rather than making any literal sense. Categorized as formulaic speech, formulaic ...

atically as any strict dividing line or point-of-no-return.

References

External links

The Human Brain: Its Size and Its Complexity
*{{cite journal , author=Ashley Montagu, title=The "Cerebral Rubicon": Brain Size and the Achievement of Hominid Status , journal=American Anthropologist, date=April 1961, volume=63, issue=2, pages=377–378, doi=10.1525/aa.1961.63.2.02a00100 , jstor=667535 Anthropology

Origin

See also

References

External links