BLASTOID FOSSIL PLATE Sea Life Matrix Mineral Specimen Echinoderm ILLINOIS RARE for Sale

BLASTOID FOSSIL PLATE Sea Life Matrix Mineral Specimen Echinoderm ILLINOIS RARE For Sale

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BLASTOID FOSSIL PLATE Sea Life Matrix Mineral Specimen Echinoderm ILLINOIS RARE:
$199.99

This fossil plate weighs 127.59 grams. The entire plate measures 66 mm x 64 mm x 35 mm.

The individual blastoid specimens range from 13 mm to 22 mm in length.

I offer ashipping discount for customers who combine their payments for multiplepurchases into one payment! The discount is regular shipping price for thefirst item and just 50 cents for each additional item! To be sure you get yourshipping discount just make sure all the items you want to purchase are in yourcart. sales you win are added to your cart automatically. For any "buyit now" items or second chance offers, be sure to click the "add tocart" button, NOT the "buy it now" button. Once all of youritems are in your cart just pay for them from your cart and the combinedshipping discount should be applied automatically.

I offer amoney back guarantee on every item I sell.If you are not 100% happy with yourpurchase just send me a message to let me know and I will buy back the item foryour full purchase price.

Hi there. I am selling this really amazing fossil plate containing tfour spectacularly detailed blastoid specimens as well as some fossil sea fan fragments! It is from the Upper Mississippian, Ridenhower Formation from St. Clair, Illinois. The blastoids are approximately 250 million years old. It's really interesting and I hope it finds a good home out there. If you have any questions please don't hesitate to ask. Thanks for shopping at my store!

Blastoid

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Blastoids

Temporal range: Ordovician - Permian

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Pentremites Glen Dean Fm KY.jpg

Pentremites godoni, a blastoid from the Lower Carboniferous of Illinois.

Scientific classification

Kingdom: Animalia

Phylum: Echinodermata

Subphylum: Blastozoa

Class: Blastoidea

Say, 1825

Orders

Fissiculata

Spiraculata

Incertae sedis:

†Macurdablastus

"Blastoidea", from Ernst Haeckel's Art Forms of Nature, 1904

Blastoids (class Blastoidea) are an extinct type of stemmed echinoderm, often referred to as sea buds.[1] They first appear, along with many other echinoderm classes, in the Ordovician period, and reached their greatest diversity in the Mississippian subperiod of the Carboniferous period. However, blastoids may have originated in the Cambrian. Blastoids persisted until their extinction at the end of Permian, about 250 million years ago. Although never as diverse as their contemporary relatives, the crinoids, blastoids are common fossils, especially in many Mississippian-age rocks.

Contents

1 Description

2 Taxonomy

3 References

4 External links

Description

Like most echinoderms, blastoids were protected by a set of interlocking plates of calcium carbonate, which formed the main body, or theca. In life, the theca of a typical blastoid was attached to a stalk or column made up of stacked disc-shaped plates. The other end of the column was attached to the ocean floor by a holdfast, very much like stalked crinoids. The stalk was usually relatively short, and in some species, was absent, with the holdfast being attached directly to the base of the theca.

The mouth was located at the summit of the theca. Radiating like flower petals from the center were five food grooves, or ambulacra. Each ambulacrum had many long, thin, fine structures called brachioles, which were used to trap food particles and bring them to the mouth. Brachioles were delicate structures, and in fossils are not usually preserved in place. A series of five spiracle plates surrounded the star-shaped mouth, which included the anus, mouth and entrances to a set of five complex, folded respiratory organs known as hydrospires. These spiracles prevented mixing of the various fluids. Waste elimination was through the anispiracle, an opening formed by the fusing of anus and adjacent spiracles.

Pentremites godoni, a blastoid from the Lower Carboniferous of Illinois; basal view of theca.

Like crinoids, blastoids were high-level, stalked suspension feeders (feeding mainly on planktonic organisms) that inhabited clear-to-silty, moderately agitated ocean waters from shelf to basin. The food gathering system of blastoids consisted of several types of ambulacra. Food entered the brachiolar ambulacra, was transferred to the side ambulacra through the brachiolar pit, then transferred to the main (median) ambulacra, and finally entered the mouth. Each of these ambulacra was roofed by cover plates. The cover plates of the brachiolar groove were movable and could open, allowing food to enter, or close as needed. Other cover plates may also have been movable.

Taxonomy