#opabiniid

[franzanth]

Utaurora comosa, the second known opabiniid

This fossil from Utah is named after Aurora (Roman goddess of dawn who turned her lover into a cicada – a modern arthropod).

The species name comosa reflects the ‘hairy’ appearance of the dorsal surface, and tail fan composed of many ‘leaves’.

This artwork was done last year but never posted here. I thought it’s appropriate to do it now, since I also just posted Mieridduryn.

Read the paper

[typhlonectes]

New opabiniid diversifies the weirdest wonders of the euarthropod stem group

Pates et al.

Abstract

Once considered ‘weird wonders’ of the Cambrian, the emblematic Burgess Shale animals Anomalocaris and Opabinia are now recognized as lower stem-group euarthropods and have provided crucial data for constraining the polarity of key morphological characters in the group. 

Anomalocaris and its relatives (radiodonts) had worldwide distribution and survived until at least the Devonian. However, despite intense study, Opabinia remains the only formally described opabiniid to date. Here we reinterpret a fossil from the Wheeler Formation of Utah as a new opabiniid, Utaurora comosa nov. gen. et sp. 

By visualizing the sample of phylogenetic topologies in treespace, our results fortify support for the position of U. comosa beyond the nodal support traditionally applied. Our phylogenetic evidence expands opabiniids to multiple Cambrian stages. 

Our results underscore the power of treespace visualization for resolving imperfectly preserved fossils and expanding the known diversity and spatio-temporal ranges within the euarthropod lower stem group.

Read the paper here:  

https://royalsocietypublishing.org/doi/10.1098/rspb.2021.2093