This article is written in British English, which has its own spelling conventions (colour, travelled, centre, defence, artefact, analyse) and some terms that are used in it may be different or absent from other varieties of English. According to the relevant style guide, this should not be changed without broad consensus.
Echinoderm is within the scope of WikiProject Animals, an attempt to better organize information in articles related to animals and zoology. For more information, visit the project page.AnimalsWikipedia:WikiProject AnimalsTemplate:WikiProject Animalsanimal articles
This article is within the scope of WikiProject Marine life, a project which is currently considered to be inactive.Marine lifeWikipedia:WikiProject Marine lifeTemplate:WikiProject Marine lifeMarine life articles
I was slightly amazed there was so little information about the evolution of Echinoderms. When I did my first-year course on invertebrates I'm sure I was told more than given here, so there must be a lot more info on this with the specialists (they were well studied). Just looking at plate 95 of Haeckels Kustformen der Natur I see weird bilateral forms from the lower Silurian period, so plenty to tell I would imagine. And also I would expect molecular biologists have more to tell. Codiv (talk) 23:08, 16 July 2022 (UTC)[reply]
Well, this is a general article and it certainly covers "the main points". The 'Fossil history' illustrates eight forms including several that are distinctly oddly shaped by modern standards, and including near-spherical, blastoid, and bilaterally-symmetric forms, so it clearly gives a clue that early forms did not much resemble the five-star form that readers will recognize. By the way, Haeckel's illustrations are often imaginative and sometimes definitely wrong, so they are unreliable guides to ancient anatomy. It might well be desirable to have an article on the Early echinoderms or indeed on the Evolution of echinoderms, but those and the more specialized detail that they might contain would naturally form subsidiary articles with "main" links from here. For comparison, Arthropod contains images of just two fossils, and it is a well-balanced article; Mollusca similarly pictures two fossils in its phylum. All the best, Chiswick Chap (talk) 08:42, 17 July 2022 (UTC)[reply]