Ehmaniella
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''Ehmaniella'' is a genus of
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 ...
known from the Middle
Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...
Burgess Shale The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest fos ...
. 392 specimens of ''Ehmaniella'' are known from the Greater
Phyllopod bed The Phyllopod bed, designated by USNM locality number 35k, is the most famous fossil-bearing member of the Burgess Shale fossil ''Lagerstätte''. It was quarried by Charles Walcott from 1911–1917 (and later named Walcott Quarry), and was ...
, where they comprise 0.74% of the community. Ehmaniella's major characteristics are a wide cranidium, heavy eye ridges, longitudinal
striae Stretch marks, also known as striae () or striae distensae, are a form of scarring on the skin with an off-color hue. Over time, they may diminish, but will not disappear completely. Striae are caused by tearing of the dermis during periods of ...
on the pre-
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 ...
r area, and a small
pygidium The pygidium (: pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is compos ...
with few segments.Coppold, Murray and Wayne Powell (2006). ''A Geoscience Guide to the Burgess Shale'', p.56. The Burgess Shale Geoscience Foundation, Field, British Columbia. .


References


External links

* Burgess Shale fossils Alokistocaridae Cambrian trilobites Cambrian genus extinctions {{Ptychopariida-stub