Irregular Sea Urchin
Vendor: Fossil Soup
SKU Number: SQ1346055
Irregular sea urchin from the Oil River, Late Ordovician locality on Anticosti Island, Quebec. Although highly worn, this is an unusual find and quite possibly an undescribed species.
The ambulacra are no longer visible and the plates of the Interambulacra are also worn away. What you can clearly see are the the anus and the mouth locations.
Irregular sea urchins are distinguished from other "Regular" sea urchins by their shape. Instead of a pentaradial symmetry they exhibit bilateral symmetry. The anus and the mouth are also not found on the dorsal and ventral surfaces of the test (Exoskeleton), but instead more towards the anterior and posterior ends.
Full dimensions are listed below.
Vendor: Fossil Soup
SKU Number: SQ1346055
Irregular sea urchin from the Oil River, Late Ordovician locality on Anticosti Island, Quebec. Although highly worn, this is an unusual find and quite possibly an undescribed species.
The ambulacra are no longer visible and the plates of the Interambulacra are also worn away. What you can clearly see are the the anus and the mouth locations.
Irregular sea urchins are distinguished from other "Regular" sea urchins by their shape. Instead of a pentaradial symmetry they exhibit bilateral symmetry. The anus and the mouth are also not found on the dorsal and ventral surfaces of the test (Exoskeleton), but instead more towards the anterior and posterior ends.
Full dimensions are listed below.
Vendor: Fossil Soup
SKU Number: SQ1346055
Irregular sea urchin from the Oil River, Late Ordovician locality on Anticosti Island, Quebec. Although highly worn, this is an unusual find and quite possibly an undescribed species.
The ambulacra are no longer visible and the plates of the Interambulacra are also worn away. What you can clearly see are the the anus and the mouth locations.
Irregular sea urchins are distinguished from other "Regular" sea urchins by their shape. Instead of a pentaradial symmetry they exhibit bilateral symmetry. The anus and the mouth are also not found on the dorsal and ventral surfaces of the test (Exoskeleton), but instead more towards the anterior and posterior ends.
Full dimensions are listed below.
Additional Information
Sea urchins belong to the Phylum Echinodermata and includes crinoids, brittle stars and sea cucumbers. The first echinoderms appear in the Lower Cambrian period.
It has been suggested that he ancestor of all echinoderms was a simple bi-laterally symmetrical animal with a mouth, gut and anus. This ancestral organism adopted an attached mode of life with suspension feeding, and developed radial symmetry. Even so, the larvae of all echinoderms are bilaterally symmetrical, and all develop radial symmetry at metamorphosis. Like their ancestor, the starfish and crinoids still attach themselves to the seabed while changing to their adult form.
