(This is a couple of days late for Halloween, but since this October saw the description of a new dinosaur species with a particularly spooky name, I couldn’t resist putting it into the schedule anyway.)
Spectrovenator ragei was an early member of the abelisaurid lineage, living in southeastern Brazil during the Early Cretaceous, about 120 million years ago. It was one of the smallest known abelisaurids, measuring just 2m long (6’6″), and lacked a lot of the skull specializations seen in larger-bodied Late Cretaceous forms like Carnotaurus, suggesting it was more of a generalist predator.
Its genus name translates to “ghost hunter” due to it being found underneath the fossil remains of another dinosaur entirely – a “ghost” unexpectedly appearing when the specimen was being prepared – but it’s extra appropriate since it also helps to fill in a rather sizeable ghost lineage in the fossil record of abelisaurids.
Named after the mythological bird-like Anzû – and also nicknamed “the chicken from hell” – Anzu wyliei was one of the larger known oviraptorosaurs, measuring about 3m long (9’10”).
Its fossils are some of the most complete for a North American member of this dinosaur group, with four different specimens representing about 80% of the whole skeleton.
Living right at the end of the Cretaceous, about 66 million years ago in North Dakota and South Dakota, USA, Anzu inhabited the ancient floodplains of Hell Creek and appears to have been a fairly fast-moving omnivorous generalist. It had a large crest on its head made of rather fragile thin-walled bone, which may have been used for display or sound amplification similar to the casque of modern cassowaries.
Some of the fossil specimens also show evidence of healed injuries, including a broken rib and an arthritic toe.
These large-headed predators were part of the hyaenodont lineage, evolutionary cousins to modern carnivorans that convergently developed similar shearing carnassial teeth in their jaws. Hyainailourids originated in Africa during the late Paleocene or early Eocene, and repeatedly dispersed into Eurasia and North America before eventually going extinct in the mid-Miocene.
Kerberos was one of the earliest of its kind known from Europe, living in Southern France during the mid-Eocene about 41-38 million years ago. It was close in size to a small American black bear, standing around 65cm tall at the shoulder (2’2″), not nearly as large as some of its later relatives but still making it one of the biggest carnivorous mammals in Europe at the time.
It was a heavily-built animal with a fully plantigrade posture, and would have been an active apex predator hunting similarly-sized early ungulates. While it wasn’t anatomically specialized for fast running it didn’t really need to be – it’s important to remember that modern bears have a similar chunky flat-footed build and yet can move surprisingly quickly.
Its incredibly powerful jaw muscles and premolar teeth adapted for bone-cracking also suggest it ate like a hyena, efficiently consuming entire carcasses.
Mainly known from mid-Triassic deposits on the Swiss-Italian border, dating around 247–235 million years ago, fossils of the species Tanystropheus longobardicus have been found in two different “morphs” – small forms less than 2m long (6’6″), and larger ones up to 6m long (19’8″).
For a long time the smaller fossils were thought to be juveniles, but while they certainly had juvenile-looking facial proportions they also had very different teeth compared to the larger forms. They had pointed teeth at the front of their mouths and multi-cusped cheek teeth further back, and the “adults” had jaws containing only the pointed teeth, suggesting very different diets and lifestyles between the two size classes.
Extreme changes in dentition and diet during maturation aren’t unheard of in fossil species, but something particularly odd was going on here. Larger forms over 2m long always had just the pointed teeth, and there were no signs of intermediate tooth arrangements at all.
And a new study using x-ray microtomography has given an answer: they weren’t actually the same species!
Turns out the smaller Tanystropheus longobardicus were all skeletally mature adults, already fully grown at that size. The larger ones were a completely separate species occupying a different ecological niche to their smaller relatives, and have been named Tanystropheus hydroides in reference to the mythical hydra.
Comparison of the skulls of T. hydroides and T. longobardicus
[ From fig 3 in Spiekman, S. N. et al (2020). Aquatic Habits and Niche Partitioning in the Extraordinarily Long-Necked Triassic Reptile Tanystropheus. Current Biology. https://doi.org/10.1016/j.cub.2020.07.025 ]
While the exact lifestyle of Tanystropheus is an ongoing paleontological argument, Tanystropheus hydroides at least appears to have been much more on the aquatic side of things, with nostrils positioned on the top of its snout and its pointed teeth forming a “fish trap” in its jaws.
Stomach contents suggest it mainly ate fast-moving aquatic prey like fish and cephalopods, but its body wasn’t really adapted for strong swimming and so it couldn’t have been catching them via active pursuit. Instead it was probably an ambush predator hunting in a similar manner to some plesiosaurs, using its incredibly long neck and relatively small head to carefully approach prey species without the rest of its body startling them, and then catching them with fast snapping sideways lunges.
Now that Spectember has wrapped up, and I’m catching my breath before we return to the regular paleo-theming of this blog, a couple extra notes:
Anyone who suggested a concept during the original submission period back in May, but didn’t see it get used this month – don’t worry! I got far more entries than I could possibly fit into the schedule (almost a hundred), and they were all wonderfully creative ideas, so I’m going to try to do something with them at a later date.
(Everyone else, please be aware I’m not currently accepting extra specevo suggestions. While I appreciate all the enthusiasm I can’t take on even more work right now.)
Also, here’s a few other neat specevo things that I didn’t have time to go into detail about this month:
Created by Gert van Dijk, a Dutch professor of neurophysiology and a talented artist (often writing under the name Sigmund Nastrazzurro), the Furaha project has been in development since 1979 – starting as a series of paintings of speculative alien creatures, and eventually expanding to detailed essays on their anatomy and ecology.
Set on the planet Nu Phoenicis IV, Furaha documents the natural history of the world and its plants and animals using paintings, illustrations, CG models, and even animations to show how their limb arrangements work. Although only a small number of organisms are featured on the main site, the associated blog provides much more information, including the incredible amount of scientific background that goes into the creation of the Furahan ecosystems.
Few specevo projects are this rigorous, with van Dijk using physical and biological constraints along with computer simulations to figure out the biomechanics of how Furahan creatures live and move, from the giant millipede-like rusps to the four-winged flying tetrapterates to the swimming membranes of the cloakfish. One of the most heavily debated subjects over the years has involved trying to determine if floating balloon-like “ballont” animals are actually possible.
The blog also occasionally discusses other elements of speculative biology and creature design, including reviews of other spec projects and media.
A fully illustrated book version of Furaha is currently in the works – although being a solo project entirely in van Dijk’s spare time it’s very much a “it’ll be done when it’s done” situation.
