Opabiniidae
Opabiniidae is an extinct family of marine stem-arthropods. Its type and best-known genus is Opabinia. It also contains Utaurora, and Mieridduryn. Opabiniids closely resemble radiodonts, but their frontal appendages were basally fused into a proboscis. Opabiniids are also distinguishable from radiodonts by setal blades covering at least part of the body flaps and serrated caudal rami.
File:20210807 Opabiniidae opabiniid trunk cross section.png|thumb|Cross section of the trunk of Utaurora and Opabinia
File:20220214 Opabiniidae size.png|thumb|Size comparison of Utaurora and Opabinia
History of study
Opabiniidae was named by Charles Doolittle Walcott in 1912, alongside its type species Opabinia. Walcott interpreted Opabiniidae as a family of anostracan crustaceans, most closely related to Thamnocephalidae. Opabinia was restudied in the 1970s, and reinterpreted as a stranger animal. Stephen Jay Gould referred to Opabinia as a "weird wonder", and an illustration of Opabinia prompted laughter when it was first revealed at a paleontological conference. In 2022, two more opabiniids were discovered, those being Utaurora and Mieridduryn.Myoscolex from Emu [Bay Shale] is sometimes suggested to be an opabiniid, but morphological features supporting this interpretation are controversial.
Works cited
Category:Dinocaridida