petalonamae – Nix Illustration

Tulaneia amabilia was an enigmatic Ediacaran animal that lived in what is now Nevada, USA just before the start of the Cambrian Period, about 540 million years ago.

Up to around 10cm across (~4″), its body was made up of a fan-shaped frill of airbed-like tubes, with tips that separated from each other and tapered to blunt points. Much like its close relative Ernietta it would have lived with its base buried in the seafloor sediment, and it was probably a suspension feeder catching organic particles in water currents.

One Tulaneia fossil specimen shows birfurcating tips, but it’s unclear whether this was a common feature of this species or a developmental anomaly in this particular individual.

Much like the sponges, the ctenophores (commonly known as “comb jellies”), are one of the oldest animal lineages, but their exact position in the evolutionary family tree is a little uncertain. Traditionally they’re placed between sponges and all other animals, as the earliest branch of the eumetazoans, but some studies have suggested that they might be much more ancient, possibly branching off before even the sponges did.

And while their fossil record is poor due to their soft gelatinous bodies, some of what we do have is starting to hint that their ancestry was very different from their modern jellyfish-like representatives – and they might even have links to some weird Precambrian creatures.

Tag: petalonamae

Tulaneia

Cambrian Explosion Month #04: Phylum Ctenophora (And Petalonamae?)