The most likely candidate eye type is the simple pigment-cup eye, which is the most widespread among the bilateria.
12.
Searches of publicly available databases of genetic sequences have found putative neuropsin orthologs in both major branches of Bilateria : protostomes and deuterostomes.
13.
All bilateria are thought to have descended from a common wormlike ancestor that appeared in the Ediacaran period, 550 600 million years ago.
14.
Recent molecular studies suggest they are related to Bilateria or Cnidaria, with Cnidaria being closer morphologically because both groups have extrusive filaments,.
15.
They work by considering the " genes " common to all bilateria, but problems arise because very similar genes can be co-opted for different roles.
16.
In this case, Schmid and Seipel argue that the last common ancestor of bilateria, ctenophora, and cnidaria was a striated muscles similar to that observed in bilaterians.
17.
Here, " C-opsins ( ciliary ) " refers to a clade found exclusively in Bilateria and excludes cnidarian ciliary opsins such as those found in the box jellyfish.
18.
The flatworms were bilateria, but they lacked coeloms, and also often lacked an anus, so were considered the earliest or a degenerate offshoot, rather than highly evolved.
19.
A modern ( 2011 ) consensus phylogeny for bilateria is shown below, although the position of certain clades are still controversial and the tree has changed considerably between 2000 and 2010.
20.
The kingdom Animalia was divided into four subkingdoms : Radiata ( phyla Porifera, Cnidaria, Placozoa, and Ctenophora ) Myxozoa, Mesozoa, and Bilateria ( all other animal phyla ).
