Halkeria
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Halkeria is an animal of unknown affinity that lived in the early Cambrian. After being known from armour fragments for several decades, intact fossil specimens were recovered in 1998 from shales in an unglaciated area of northeast Greenland.
The animal turns out to be an armored worm-like form a few centimeters in length with two distinctive features. The body armor is made of hollow spines known as sclerites. The head and tail each bear a shell that in very similar to that of inarticulate brachiopods. The resemblance to the middle Cambrian form Wiwaxia is not terribly surprising, but the connection between these and the sponge-like Chancelloria is a mystery. The presence of brachiopod-like shells is a total (and not especially welcome) surprise. It is possible that Halkeria is related to later animals known as Machaerids and/or to sclerite bearing worm like animals from the Lower Cambrian of China.
- External link: Halkieriida at palaeos.com (http://www.palaeos.com/Invertebrates/Procoelomates/Halkieriida.html)