Eocryphops sp (with reduced Schizochroal Eye Facets)

Trilobites Order Phacopida Suborder Phacopina, Superfamily Phacopoidea, Family Phacopidae
Geologic Age: Middle Devonian
Trilobite is 24 mm long
Jorf, Morocco
Remarks: Eocryphops presents somewhat of an evolutionary mystery. Note the very small number of Schizochroal Eye facets. Some three-to four fold more is more typical in Suborder Phacopina. Such a reduction eyes was not uncommon in phacopida, especially in the Devonian period, and is also seen in genus Plagiolaria (Holloway, 2005) - also see (Crônier and Fortey, 2006). This trilobite cames from Jorf in Morocco where a reduced eye Gerastos proetid and a blind Gerastos also occur. Apparently the environment at Jorf in the Devonian lacked positive selection for eye sight in some trilobites. Mysteriously, trilobites with reduced eyes are found in association with species with typical eyes. While the environment is believed to have been in deep water, it was still one in the photic zone, where good eye sight would seem to have been a survival benefit and selected for. Was there a particular niche in the environment where good sight was not selected for, or even selected against, leading to secondary eye loss? Was the Eocryphops trilobite we see here actually blind, and its reduced eyes just vistigal organs?

Also see: Moroccan Trilobites Evolutionary Secondary Blindness Among Trilobites Trilobite Eyes










Eocryphops Phacopid Trilobite

Eocryphops trilobite Schizochroal Eyes with greatly reduced number of facets:

Eocryphops Moroccan Trilobite

Eocryphops trilobite Schizochroal Eye with greatly reduced number of facets