Definition of Crossopterygii
1 : a superorder of Choanichthyes comprising the lobe-finned fishes that have existed since the Devonian but are now largely extinct, that have paired fins somewhat resembling limbs with a scaly axis fringed on one or both sides by dermal rays, and that are generalized fishes in some respects resembling elasmobranchs and in others foreshadowing terrestrial vertebrates which may have evolved from unknown early members of the group — compare latimeria
Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.
Start your free trial today and get unlimited access to America's largest dictionary, with:
- More than 250,000 words that aren't in our free dictionary
- Expanded definitions, etymologies, and usage notes
- Advanced search features
- Ad free!
Origin and Etymology of crossopterygii
New Latin, from cross- + -pterygii
Seen and Heard
What made you want to look up Crossopterygii? Please tell us where you read or heard it (including the quote, if possible).