''Coltraneia'' is a genus of

trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...

, that lived during the upper Emsian and lower Eifelian, and has been found in Algeria, France, Germany, Morocco and Spain.

Description

The frontal lobe of the central raised area of the headshield (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 to ...

) is rounded. The furrow defining the glabella is curved behind the frontal lobe. Both lobes directly behind the frontal lobe (L3 and L2) are more elevated than the lobe (L1) just in front of the occipital ring (L0). All sighted phacopina have schizochroal eyes, but in ''Coltraneia'' these are particularly large with 13–14 lenses in each of the vertical rows (or

dorsoventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

file) at midlength. The front of these eyes almost touches the furrow separating the frontal from the following lobe, while the back of the eyes touch the posterior border furrow. The axis of the tailshield (or pygidium) has 13 to 15 rings, and is constricted between the 6th and 7th rings. In the pleural region to the side of the pygidial axis, 8–11 segments can be identified. The five pairs of pygidial spines (or lappets) extend from both the anterior and posterior pleural bands. These lappets are shorter than the corresponding pleural segments, narrow and pointed, more so further to the back. The terminal medial spine is so short, it almost is confluent with the lateral edge of the pygidium between the spines.

Taxonomy

left, The anterior border in ''Coltraneia'' is arched''Coltraneia'' is most related to ''Treveropyge'' from which it differs by larger eyes with 13-14 lenses per file, rather than 8-12 lenses. ''Treveropyge'' only has 12-13 pygidial rings with a constriction between the 4th and 5th ring, and lappets as long as the corresponding pleural segments, while the terminal medial spine is short but triangular. Viewed from the front the anterior border in ''Treveropyge'' is straight, while in ''Coltraneia'' it is arched upwards like a fold in a rug.

Etymology

''Coltraneia'' is named for the jazz saxophonist John Coltrane.

References

{{Taxonbar, from=Q15477141 Acastidae Devonian trilobites of Europe Fossils of Algeria Fossils of France Fossils of Germany Fossils of Morocco Fossils of Spain Early Devonian first appearances Eifelian extinctions Devonian trilobites of Africa