Sam Gon III's A Guide to the Orders of Trilobites (June 19, 2009)
"Given that trilobites are Arthropods, what is their place among the known arthropod groups?..."
"...For a long time, trilobites were considered the most primitive of arthropods, since they were among the first Cambrian arthropods discovered, but this turns out to have been mistaken; an artifact of preservation. The first recorded Cambrian outcrops only preserved species with hard, shelly parts, such as trilobites, brachiopods, mollusks, and echinoderms. When the Burgess Shale, Chengjiang, and other similar Cambrian Konservat-Lagerstätten (remarkably preserved fossil deposits) were discovered, large numbers of more delicate Cambrian arthropod species (that typically do not preserve at all) were revealed as contemporaries of trilobites, rather than their descendants (see diorama below)...."
Have you ever awakened in the small hours of the morning, wondering "were trilobites, anomalocaris, and hallucigenia alive around the same time?"
But if you were, you're in for a treat: because here's an article that will help you sleep nights.
About those names: hallucigenia is a - thing - that looks sort of like a spikey worm - or a walking siphon - or something; anomalocaris looks like it swam out of someone's nightmare - and was the last thing many trilobites saw.
I don't know how authoritative the information in the article is - but the author lists quite a number of sources, which is often an indication that someone's bothered to research their subject.
The page is amply illustrated, and written so that someone who's moderately familiar with Cambrian animals should be able to follow what's going on.
- "Astrobiology, the Vatican, and the Meaning of Our Existence"
A Catholic Citizen in America (November 12, 2009)
- "Trilobites, Arthropods, Evolution, and Why Mothra Isn't Real"
(October 17, 2009)
- "Change, American Culture, Trilobites, Humanity's History, and the Big Picture"
(September 26, 2009)