Starfish first appeared in the fossil record in the Cambrian. The first known asterozoans were the Somasteroidea, which exhibit characteristics of both groups. Starfish are infrequently found as fossils, possibly because their hard skeletal components separate as the animal decays. Despite this, there are a few places where accumulations of complete skeletal structures occur, fossilized in place in Lagerstätten — so-called "starfish beds". By the late Paleozoic, the crinoids and blastoids were the predominant echinoderms, and some limestones from this period are made almost entirely from fragments from these groups. In the two major extinction events that occurred during the late
Chloroflexi (phylum) Class Thermomicrobia Class Chloroflexia The name ""Chloroflexi"" is a Neolatin nominative case masculine plural of "Chloroflexus", which the name of the first genus described. The noun is a combination of the Greek adjective "chloros, -a, on (χλωρός, -ά, -όν)" meaning "greenish-yellow" and the Latin masculine passive perfect participle "flexus" (of "flecto") meaning "bent" to mean "a green bending". It should be therefore noted that the etymology is not due to chlorine, an element (dephlogisticated muriatic acid air) which was confirmed as such in 1810 by Sir Humphry Davy and named after its pale green colour. Another phylum with the same