Hardouinia kellumi echinoid from the Pee Dee formation

Echinoids are cool critters that come in two basic flavors, regular and irregular. The regular echioids are the ones you see in aquariums and on nature shows with the long spines crawling along the bottom of the reef. Irregular echinoids are more often partially submerged in the sediment and do not have large showy spines.  Hardouinia kellumi is an example of an irregular urchin and could also be known as a sea biscuit.  The specimen below is from the Cretaceous ages sediments at Rocky Point Quarry in North Carolina. It comes from the Peedee formation which is dated to the late Maastrichtian (66-67 mya)

Adaptical surface

Anterior

Left profile

Posterior

Right profile

Adoral surface

Macraster sp. echinoid from the Duck Creek formation of Texas

Not only does the Duck Creek formation have ammonites, it has some echinoids as well. I found a couple of nicely inflated specimens of the irregular echinoid Macraster. I sent pictures of my find to a friend in Texas, who is familiar with the Duck Creek formation, and he said they could be either M. elegans or M. washitae. Macraster has a suboval shaped test with a sub rectangular cross section. The adapical surface has the typical five arm imprint of the ambulacra which is where the feet of the animal would have extended from. There is a small oval shaped opening in the posterior of the test called the periproct which is where the anus of the animal would have been. On the underside, or adoral surface, is the opening for the animals mouth called the peristome.

When I was a kid I called echinoids with this shape "sea biscuits".

Specimen #1 is a little water worn.
Adapical surface

Posterior

Left profile

Anterior

Right profile

Adoral surface

Specimen #2 is missing some of the test on the adoral surface
Adapical surface

Posterior

Left profile

Anterior

Right profile

Adoral surface

The only other Echinoid evidence that I found was this isolated piece from a regular echinoid.

The above specimens come from the Duck Creek formation which is Cretaceous (Albian stage) in age.

Coenholectypus planatus echinoid from the Walnut formation of Texas

This round echinoid is Coenholectypus planatus echinoid from the Walnut formation of Texas (Cretaceous, Albian stage). It is one of many that I have received from a friend who collects in the Lone Star State. The test is round when viewed from the dorsal or ventral sides and shaped like a dome when viewed from the sides. In like it would have been covered with many small spines, the bases of which you can see preserved. I think this is considered a "regular" echinoid due to it's shape. Based on the shape of the test and small spine bases I think that C. Planatus would have lived in the littoral zone in rocky and sandy areas.

Adoral surface

Profile views

Oral surface

Macraster ibizaensis echinoid from Spain

This is a nice specimen of Macraster ibizaensis from the Aptian stage of the Cretaceous near Jbiza, Spain. Thank you to my friend Karoly for the cool specimen!

Adapical surface (top)

Anterior (front)

Side profile

Posterior (rear)

Side profile

Adoral surface (underside or bottom)

Rhyncholampas gouldii echinoid from Florida

Here we have a Rhyncholampas gouldii echinoid from FL. It was found in the Oligocene aged Suwannee Limestone southeast of Tallahassee. It is very similar in appearance to the genus Hardouinia (Cretaceous) but is found much later in the geologic column.

Adapical surface (top)

Anterior

Right profile

Posterior

Left profile

Adoral surface (underside or bottom)

The label that was originally included with this specimen listed it as Rhynchopygus but that genus is only valid in the late Cretaceous of Europe.

Arbacina monilis echinoid from Hungary

The wee regular echinoid pictured below is Arbacina monilis from the Eocene near Nyirád, Hungary. I received them as part of an exchange with a collector in Hungary. The fossils have a bit of matrix on them still but you can clearly see the tubercles (the round bumps that the spines attach to). The fossils are from the Badenian stage of the Miocene which corresponds to the Langhian stage of the ICS).

Apical side

Oral side

Thanks to Karoly for the fossils!

Echinocorys vulgaris echinoid from Spain

I've featured the genus Echinocorys before from both France and Denmark. Below is a specimen of Echinocorys vulgaris from Spain that comes from the Navarro-Cantabrian Basin in northern Spain.

Thank you to my friend Jenaro for this fossil. The rocks of the Navarro-Cantabrian Basin are dated to the Santonian stage of the Cretaceous.

Heteraster, Nucleopyrina and Coelopleurus echinoids from Spain

Here are three small echinoids that I received in a trade with a friend in Spain. I'll start off with Heteraster oblongus from the Cretaceous (Aptian stage) near Castellon, Spain

Next is Nucleopyrina cylindrica from the Cretaceous (Aptian stage) near Castellon, Spain

Finally there is Coelopleurus coronalis from the Eocene (Lutetian stage) near Barcelona, Spain

Thanks to my friend Jenaro for these fossils.