Hox genes
in brachiopods and priapulids and protostome evolution.
Not exact matches
A little further
in the rock record, a few
brachiopod species recover, Wignall says, and then mollusks take over en masse, before the devastation of the Permian extinction, 8 million years later.
For years, scientists have been debating the phylogenetic position of
brachiopods and molluscs, as well as their affinities for other animals
in the same group, the Lophotrochozoa, comprising segmented worms, clams, oysters, snails, squids, and so on.
The Navesink Formation preserves many invertebrate and vertebrate species common
in the Late Cretaceous near shore marine sediments, such as bivalves,
brachiopods, crustaceans, teleost fish, sharks, turtles and the occasional mosasaur and dinosaur.
A similar arrangement also occurs
in mollusk (23) and
brachiopod larvae (24), and ventral midline muscles are observed
in most lophotrochozoan phyla (table S3), suggesting that an axochord is ancestral for lophotrochozoa.
The Devonian is often appropriately called the «Age of Fishes», since the fish took their place
in complex reef systems containing nautiloids, corals, graptolites, blastods, echinoderms, trilobites, sponges,
brachiopods and conodonts.
Permian marine environments were abundant
in mollusks, echinoderms, and
brachiopods.