Troll_Man

WWD: Thalassodraco etchesi

Added 2023-04-26 10:17:59 +0000 UTC

Possibly the most infamous episode of the original series, for reasons that will be seen very soon. This is the point where the series starts getting a bit liberal with what lived when, because nearly every animal in the original episode, set during the Mid Tithonian, is only known from the Early Oxfordian epoch, about fifteen million years earlier. This isn't entirely their fault, since several of the genera depicted were once thought to have longer temporal ranges, but it's since been found this only seemed so because they were wastebasket taxa. This includes the first genus, Ophthalmosaurus; at least five different species have since been split off from it since 2000, and several other fragmentary ichthyosaur fossils assigned to it are considered dubious.

The locale for the episode has been changed from the Oxford Clay to the Kimmeridge Clay, for the obvious reason of reducing any possible anachronisms and keeping the original time period. A number of ichthyosaur species are known from the formation, but to help keep the predator-prey size dynamic the same, I chose the smallest one from the site, Thalassodraco, which is known from a nearly complete skeleton. Functionally, it's about the same, partly because it was a very close relative of Ophthalmosaurus and partly because ichthyosaurs tend to be same-y in appearance from the Mid Jurassic onward.

The episode depicted adult Ophthalmosaurus as being toothless; this was based on a fossil lacking teeth, but it is now known that the animal had teeth in life, but they fell out during the decomposition process. But, overall, compared to the other prehistoric animals of WWD, there are relatively few flaws, mostly because ichthyosaurs were known from complete fossils since the early 19th century, and their close physical similarity to a certain living marine tetrapod makes their appearance and lifestyle easy to infer. It's a lot harder to make mistakes about them.