Fossil Starfish - 4.58" Petraster
Fossil Starfish - 4.58" Petraster
Starfish are one of the oldest groups of animals in the fossil record. Their iconic body shapes have remained relatively unchanged through hundreds of millions of years, which is a testament to their evolutionary success.
This specimen is a 4.58" Ordovician Petraster Starfish fossil, which lived over 440 million years ago. Members of the genus could be found all over the world and resembled modern starfish in shape and behavior. This particular starfish comes from the Ktaoua Formation in Morocco.
📸 The fine detail of a fossilized Pestraster Starfish
Starfish are a truly ancient group of animals and have survived a number of extinction events since their first appearance in the fossil record during the Cambrian.
This specimen is an Ordovician Petraster Starfish, which lived over 440 million years ago. Members of the genus could be found all over the world and resembled modern starfish in shape and behavior. These starfish come from the Ktaoua Formation fossil beds in Morocco.
📸 A Sample Fossil Starfish Plate
Petraster starfish lived their whole lives on the ocean floor. Upon their death, they were covered in loose sediments and fossilized over the course of millions of years. This fossil is an imprint of one such starfish.
This specimen is a one-of-a-kind fossil starfish which comes with a a stand for display. An informational card that serves as a certificate of authenticity is also included.
Each of these fossil starfish is a unique item and sold by size. You can see all of our starfish at the collection below!
MORE ABOUT STARFISH
ESTIMATED AGE : c. 440,000,000 years old
Ancient stars of the sea
Starfish have existed in the fossil record for hundreds of millions of years, making them one of the oldest groups of animals on the planet. While they are slow moving, starfish have been incredibly important predators in the benthic ocean food chain.
The first fossil evidence we have of starfish is over 480,000,000 years old, coming from the early Ordovician period. This means that they appeared only a few million years after the Cambrian explosion brought diverse and complex life to the seas. Several subgroups of Asterozoa have been observed, but all include the iconic star shaped body and radial symmetry.
In spite of their passive appearance, starfish are voracious hunters, scouring the benthic zone for any unlucky mussel or clam that may come their way. Throughout their history, they have played the role of ocean floor predator. Ancient starfish crawled with small tube feet under their bodies, and could use their arms to toss food at their mouth slits.
Petraster in particular was an especially brutal hunter. When it discovered its prey, usually a mollusc, Petraster would raise the center of its body up and over the meal. It would then descend like a dome over the unfortunate bivalve, prying open the shell with its tube feet and feeding with a central mouth.
Even though Petraster was slow moving, its prey was plentiful and even slower. This meant that the starfish could thrive as a top bottom feeder predator. However, its role in the ecosystem didn't stop at predation– it was also an important food source for even larger animals. Early fish, cephalopods, and perhaps even sea scorpions may have found a tasty snack in the starfish. This made them a ubiquitous middle step in the food web between small creatures and apex predators.
Petraster thrived across much of the global ocean in its time and fossils have been found all over the world. These particular specimens come from the Katoua formation in Morocco, which dates back to the Ordovician.
Fossilization and Deep Time
Starfish which died of disease or age remained intact on the ocean floor and could be covered with sediment before decomposers destroyed the body. These animals then underwent the process of fossilization, preserving them in stone for millions of years. Petraster fossils show the body structure of these animals in fine detail. When examining them, you can make out the texture of their arms and identify markings of tube feet, spines, and even mouth slits.
When looking at a starfish fossil today, it is quite easy to see how similar they were to modern specimens. This is a testament to the Asteroidea group's staying power. Starfish have been around since long before the dinosaurs, and have long outlived them as well. Members of the class survived all six mass extinctions since the Cambrian with a relatively consistent body structure throughout. Though we may think of them as small and slow creatures, they are actually highly adaptable and highly successful through much of deep time.
Front of the Specimen Card
Back of the Specimen Card
Spencer, W. K. “Early Palaeozoic Starfish.” Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, vol. 235, no. 623, 1951, pp. 87–129.
“Petraster.” Mindat.org, https://www.mindat.org/taxon-4872699.html.