Erbenochile
Encyclopedia
Erbenochile is a genus of spinose phacopid (acastid) trilobite found in Lower to Middle Devonian
age rocks from Algeria
and Morocco
. Originally described from an isolated pygidium (the posterior body part or shield), the first complete articulated specimen of E. erbeni revealed the presence of extraordinarily tall eyes:
Number of lenses has been estimated at 560 or 450 incomplete preservation accounting for the uncertainty. A lens count of 18 lenses per file is unusually high (twice that of closely related genus) and accounts for the height of the eye, as opposed to a noticeable increase in the size of the individual lenses. A recently found undescribed species of Erbenochile has smaller eyes, with fewer files (33-35) and fewer lenses per file (15 max) than E. erbeni. E. erbeni eyes allow full 360 degree coverage in the horizontal plane and were high enough to allow the trilobite to see backwards over its thorax. The presence of eye shades, blocking glare from over head, validates the suggestion that (at least some) trilobites were diurnal and not nocturnal,
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
age rocks from Algeria
Algeria
Algeria , officially the People's Democratic Republic of Algeria , also formally referred to as the Democratic and Popular Republic of Algeria, is a country in the Maghreb region of Northwest Africa with Algiers as its capital.In terms of land area, it is the largest country in Africa and the Arab...
and Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
. Originally described from an isolated pygidium (the posterior body part or shield), the first complete articulated specimen of E. erbeni revealed the presence of extraordinarily tall eyes:
Number of lenses has been estimated at 560 or 450 incomplete preservation accounting for the uncertainty. A lens count of 18 lenses per file is unusually high (twice that of closely related genus) and accounts for the height of the eye, as opposed to a noticeable increase in the size of the individual lenses. A recently found undescribed species of Erbenochile has smaller eyes, with fewer files (33-35) and fewer lenses per file (15 max) than E. erbeni. E. erbeni eyes allow full 360 degree coverage in the horizontal plane and were high enough to allow the trilobite to see backwards over its thorax. The presence of eye shades, blocking glare from over head, validates the suggestion that (at least some) trilobites were diurnal and not nocturnal,
External links
- Big-eye trilobite: Erbenochile - Natural History Museum (London) virtual tour
- Richard ForteyRichard ForteyRichard A. Fortey FRS is a British palaeontologist and writer.-Career:Richard Fortey studied geology at the University of Cambridge and had a long career as a palaeontologist at the Natural History Museum in London. Prof. Fortey’s research interests include, above all, trilobites...
's book cover Fossils - key to the past features E. erbeni