Ophiura
A cosmopolitan genus of echinoderms in the family Ophiuridae.
Ophiura is a genus within the echinoderm family Ophiuridae. Its members are found worldwide. The genus contains both living species and those known only from fossils; the oldest confirmed fossil species, *Ophiura achatae*, dates from the Early Paleocene.
Quick Facts
- Taxon
- Ophiura
Facts from the source article.
Lore & Background
Ophiura is a genus within the family Ophiuridae, comprising both living and fossil species. The genus has a cosmopolitan distribution, meaning its members are found worldwide. The taxonomy includes a list of extant species, though the source article does not enumerate them individually. The fossil record of Ophiura is well documented, with definitive fossil species known from the Early Paleocene onward, the earliest being Ophiura achatae described by Rasmussen in 1972. Other definitive fossil species include Ophiura bartonensis, Ophiura bognoriensis, Ophiura costata, Ophiura furiae, Ophiura hendleri, Ophiura marylandica, Ophiura paucilepis, Ophiura pohangensis, ?Ophiura sternbergica, and Ophiura wetherelli. These species span various geological periods, with authors such as Rasmussen, Blake & Aronson, Berry, Stöhr, Jagt & Klompmaker, Ishida et al., Kutscher, and Forbes contributing to their descriptions.
Reader's Guide
The significance of Ophiura lies in its extensive fossil record, which provides insights into the evolutionary history of ophiuroids. The genus dates back to at least the Early Paleocene, as evidenced by Ophiura achatae, and includes numerous definitive fossil species described by multiple researchers over decades. Notably, the article also lists former fossil species originally placed in Ophiura but now reassigned to other subdivisions or recognized as not belonging to the genus. These former species, dating back to the Early Jurassic, include Ophiura astonensis, Ophiura bridgerensis, Ophiura cretacea, Ophiura graysonensis, Ophiura davisi, Ophiura parviformis, Ophiura straini, Ophiura texana, Ophiura tinurtiensis, Ophiura travisana, Ophiura utahensis, and Ophiura vindobonensis. This distinction highlights the ongoing refinement of ophiuroid taxonomy, where earlier assignments are revised as new evidence emerges. The cosmopolitan distribution of Ophiura further underscores its widespread occurrence across ancient and modern seas, making it a key genus for studying echinoderm biogeography and paleoecology.
Did You Know?
- Ophiura belongs to the family Ophiuridae.
- The genus has cosmopolitan distribution.
- The earliest definitive fossil species is Ophiura achatae from the Early Paleocene.
- Twelve former fossil species originally placed in Ophiura are now thought to belong to a different subdivision.
Frequently Asked Questions
What is Ophiura?
Ophiura is a genus of brittle stars that falls under the family Ophiuridae. It encompasses both living species and those known exclusively from the fossil record.
Where do Ophiura species occur?
Members of this genus are found in ocean waters on every continent, giving the group a truly cosmopolitan range. This worldwide distribution makes Ophiura one of the more broadly represented brittle-star genera.
How far back does the Ophiura fossil record extend?
The oldest unambiguously identified fossil, Ophiura achatae, dates to the Early Paleocene. That places the confirmed lineage just after the Cretaceous–Paleogene mass-extinction boundary.
How many fossil species are currently assigned to Ophiura?
Eleven species are firmly recognized as definitive fossils of the genus. A further twelve species were once placed in Ophiura but have since been moved to other taxa.
Why is Ophiura significant to echinoderm fans and researchers?
Because it spans both extant and deep-time species across a global range, Ophiura provides a long, continuous window into brittle-star evolution. Its cosmopolitan presence also makes it a handy reference point when comparing ancient and modern echinoderm diversity.
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