In the midst of the Cambrian Period, life took on many different shapes and sizes. Most sea creatures evolved symmetrical, stable forms, but there were a few rebels that bucked this trend.

Carpoids may be closely related to their echinoderm cousins like starfish and sand dollars, but they lack their fivefold symmetry. Instead, these sea creatures appeared in unusual asymmetrical forms, making each fossil utterly unique.

These Carpoid specimens were uncovered in Morocco's Ktaoua Formation. Each specimen has been individually photographed and listed by size and all of them come complete with an informational card that serves as our statement of authenticity.

You can explore all the specimens in the collection below!

Nature prizes the efficiency of symmetrical forms, but not every animal follows this trend. Carpoids, also known as homalozoa and calcichordates, share many traits with their echinoderm cousins like starfish and sand dollars but without their fivefold radial symmetry. Instead, carpoids spawn off in asymmetrical forms that vary considerably species by species. These unusual shapes are just the most obvious eccentricity in their form. Carpoids seem to lack the water vascular system seen in other echinoderms and are armored with an exoskeleton of monocrystalline calcite plates. They also may have had gills or gill slits.

Because of these unusual features, finding the carpoid branch on the evolutionary tree has been a difficult task. The creatures are very basic members of the deuterostomia superphylum that also includes echinoderms, the worm-like hemichordates, and the chordates of which humans and all other vertebrae are a part. Pinning down Carpoid’s exact place in evolution might tell us much about when their unusual traits first appeared in nature. Complicating matters are the differences between the four main Carpoid groups: ctenocystoids, cinctans, solutes and stylophorans

When they were discovered in the 1850s, Carpoids were first thought to be primitive echinoderms, evolving before radial symmetry appeared. In the 1960s, a counter position suggested that the solutes and the stylophorans groups were early chordates, while a third theory holds that Carpoids are advanced echinoderms that lost their radial symmetry during their evolutionary trajectory. If Carpoids are chordates, that would mean that these unusual sea creatures are direct ancestors of all of humanity. Lucky for us, we’re a bit more symmetrical than our forebearers.