''Eoagnostus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

from a well-known class of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

marine

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

s, the

trilobite Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most succ ...

s. It lived during the terminal Lower Cambrian (

Toyonian Cambrian Stage 4 is the still unnamed fourth stage of the Cambrian and the upper stage of Cambrian Series 2. It follows Cambrian Stage 3 and lies below the Wuliuan. The lower boundary has not been formally defined by the International Commission ...

), until the earliest Middle Cambrian (earliest ''Kounamkites''-zone, part of the lower Amgaian).

Distribution

* ''Eoagnostus roddyi'' terminal Lower Cambrian of the United States (''Bonnia''-zone, Kinzers Shale, Lancaster, New York; Pennsylvania; Vermont)Whittington, H. B. et al. Part O, Treatise on Invertebrate Paleontology. Revised, Volume 1 – Trilobita – Introduction, Order Agnostida, Order Redlichiida. 1997 and the early Middle Cambrian of Newfoundland, and Greenland (around the boundary of ''Ovatoryctocara''-zone, Henson Gletscher Formation). * ''Eoagnostus acrorhachis'' occurs in the terminal Lower Cambrian of the United States (''Bonnia''-zone, Hatch Hill, New York).

Description

Almost identical to ''

Archaeagnostus ''Archaeagnostus'' is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived from the terminal Toyonian Cambrian Stage 4 is the still unnamed fourth stage of the Cambrian and the upper stage of Cambrian S ...

'', but the frontal lobe of the central raised area of the cephalon (or

glabella The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior ...

) is effaced, while the back of glabella is inflated.

References

Peronopsidae Agnostida genera Cambrian trilobites Fossils of Greenland Fossils of the United States {{agnostida-stub