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
Broad-headed spiny rat end of the wet season. Broad-headed spiny rat The broad-headed spiny rat ("Clyomys laticeps") is a spiny rat species from South America. The etymology of the species name is the Latin word "laticeps" meaning "wide-headed". The species has a head-body length that ranges from , with a tail long, and weigh between . They have short ears and limbs, and feet with powerful claws adapted for digging. The fur is interspersed with spines; it is grizzled reddish or yellowish and black over most of the body, and paler grey to almost white on the underparts. Broad-headed spiny rats are native