bird – Page 6 – Nix Illustration

Island Weirdness #04 – Gargantuavis philoinos

By far the biggest island in the Late Cretaceous European archipelago, the Ibero-Armorican island (sometimes also known as the Ibero-Occitan island) was made up of most of the Iberian Peninsula and France and was larger than modern-day Madagascar.

Around 73-71 million years ago one of the residents of this island was the aptly-named Gargantuavis – the largest known Mesozoic bird, and probably an example of island gigantism.

Although only known from a few isolated bones, it’s estimated to have been slightly larger than a modern cassowary, somewhere in the region of 2m tall (6′6″). At that size it would have also been secondarily flightless, which is surprising for a bird that was living alongside larger fast-moving theropods like abelisaurs.

Not much else is known about it due to the scarce remains, but it seems to have had a long slender neck and probably had a small head. Its hips were fairly broad, suggesting it wasn’t capable of running very fast, and it was likely a slow-moving herbivore that was a fairly rare member of its ecosystem.

Exactly where it belongs in the bird evolutionary tree is also unclear, with the best current guess being “some sort of euornithean”.

Enantiophoenix

Enantiophoenix electrophyla, an enantiornithean bird from the Late Cretaceous of Lebanon (~95 mya).

It was similar in size to a modern starling, around 20cm (8″) long, and although only known from a fragmentary fossil it had fairly chunky leg bones with large claws. It was probably a strong percher like most other avisaurid enantiornitheans.

Several tiny pieces of amber were also found within the fossil, which have been suggested to be stomach contents. This could perhaps be evidence of Enantiophoenix feeding on tree sap like modern sapsuckers, but without a known skull it’s hard to tell for certain whether it was specialized for that sort of diet or not.

Eons Roundup

This year I’ve been lucky enough to have some of my work featured in several PBS Eons videos – and I even recently got the opportunity to do some custom images for them! Since I didn’t show any of these off at the time, here they are now:

The basal temnospondyl amphibian Iberospondylus, from “When Giant Amphibians Reigned”
https://www.youtube.com/watch?v=rGthtRZl8B0

The flying paleognath bird Lithornis, from “When Birds Stopped Flying”
https://www.youtube.com/watch?v=M3h05ajJw0o

The ground sloth Nematherium, from “How Sloths Went From the Seas to the Trees”
https://www.youtube.com/watch?v=pt9tBtQoAHo

Happy new year, everybody!

Almost-Living Fossils Month #26 – Angry Land-Flamingo-Ducks

The presbyornithids were an early group of waterfowl birds – relatives of modern ducks, geese, swans, and screamers – that first appeared in the Late Cretaceous, about 71 million years ago. With their long necks, long legs, and duck-like bills adapted for filter-feeding, they seem to have essentially been primitive ducks converging on the body shape and lifestyle of flamingos – and as a result they’re sometimes even nicknamed “flamingo ducks”.

They lived in shallow freshwater environments all around the world, and after surviving through the end-Cretaceous extinction they even became some of the most common waterbirds in the early Cenozoic. Some species have been found in large bonebeds containing fossils from thousands of individuals all in one place, suggesting they were very social and lived in huge flocks.

Around the mid-to-late Eocene (~40-37 mya) they seemed to disappear completely, until some fossils from Australia that were originally thought to be from a species of ancient stone-curlew were reassessed in 2016 and found to actually represent the latest-surviving members of the presbyornithids.

Named Wilaru, this bird lived in South Australia during the Late Oligocene and Early Miocene (~28-20 mya). Two different species have been identified: Wilaru tedfordi and its slightly larger and stockier descendant Wilaru prideauxi. With only partial pieces of their skeletons known it’s difficult to estimate their full life size, but based on similar presbyornithids they were probably both somewhere around 1m tall (3′3″).

As well as outliving the rest of their kind, the two Wilaru species were also rather weird compared to the other known flamingo-ducks, with adaptations that indicate they were spending much more time walking around on land than wading in water. Their feet resembled those of modern screamers (which are also more terrestrial) and may have partially or fully lost their webbing, and since they lived alongside various other species of waterfowl and early flamingos they clearly weren’t competing for the same ecological niches. It’s possible they might have also shifted away from their ancestral filter-feeding diet, perhaps becoming more herbivorous, but without any preserved skulls we can’t tell for certain.

Unlike other presbyornithids they also had large spurs on their wings – and based on the behavior of modern spurred waterfowl this suggests they were much less social. They were probably rather aggressive animals, living solitary or in pairs and fighting each other over mates and territory.

This major departure from the lifestyle of their ancestors may have been what allowed Wilaru to survive for so much longer than all the other presbyornithids. They might potentially have lasted a few more million years into the mid-Miocene, but a cooling and drying climate – especially a sudden temperature drop about 14 million years ago – may ultimately have altered their habitat and food sources too quickly for them cope with.

Copepteryx

Copepteryx hexeris, a plotopterid bird from the Late Oligocene of Japan (~28-23 mya).

Known from around the North Pacific rim from about 33-15 million years ago, plotopterids were flightless diving birds which used their small but powerful wings to propel themselves through the water. They were convergently similar to penguins in body shape and lifestyle, but not actually closely related to them – instead being relatives of gannets, cormorants, and anhingas.

Smaller plotopterids were about the size of modern cormorants, around 70cm long (2′4″), but the larger known genera like Copepteryx rivalled the southern giant penguins at around 1.8m (6′).

And a second species of Copepteryx known only from a single leg bone (Copepteryx titan) may have been ever bigger. Estimated at over 2m in length (6′6″), it was possibly one of the largest diving birds to have ever lived.

Ergilornis

Ergilornis rapidus, a 1.2-1.5m tall bird (4′-5′) from the Early Oligocene of Mongolia (~33-28 mya). Closely related to modern cranes, trumpeters, and limpkins, it was part of an extinct group called eogruids – flightless birds which existed across Eurasia for a large portion of the Cenozoic from roughly 40-3 million years ago.

Although the earliest known eogruids were smaller and less specialized, and may even have still been somewhat capable of flying, later forms like Ergilornis had highly reduced wings, long legs adapted for running, and convergently ostrich-like feet with only two toes each.

Longipteryx

Longipteryx chaoyangensis, an enantiornithine from the Early Cretaceous of China, about 120 million years ago. With a body length of only around 15cm (6″), it had a long snout tipped with a few hooked teeth and feet capable of perching – features that indicate it may have lived very similarly to modern kingfishers, feeding on fish and small invertebrates in its swampy forest habitat.

The enantiornithines were a sort of “cousin” lineage to modern birds. Most had toothy jaws and clawed wings, and the wide variety in their skull shapes suggests that they were specialized for many different dietary niches. The entire group went extinct during the K-Pg mass extinction and left no living descendants, but during the Cretaceous they were the most widespread and diverse group of birds*, with fossils currently known from every continent except Antarctica.

* Depending on how you define “bird”.

Jamaican flightless ibis

The Jamaican ibis (Xenicibis xympithecus) was a bird unique to the Caribbean island of Jamaica. One of only two known types of completely flightless ibises, it was similar in size to a chicken – probably around 75cm long (2′5″) and weighing 2kg (4.4 lbs).

It had some incredibly unusual wing anatomy, with strengthened bones, a proportionally short forearm, and the “hand” section modified into a thick club-like shape. Some remains show evidence of blunt-force injuries, suggesting these birds fought each other by swinging around their heavy wings like baseball bats.

Its bones have found in several cave deposits which are difficult to accurately date, but are likely to be somewhere between 10,000 and 2,200 years old. It’s unclear whether Xenicibis was still around when humans first colonized the island, but if so it was probably driven to extinction soon after.

Turtle-jawed moa-nalo

The turtle-jawed moa-nalo (Chelychelynechen quassus) was a large flightless goose-like duck from the Hawaiian island of Kaua‘i. About 90cm tall (3′) and weighing around 7kg (15lbs), these birds and their relatives were descended from dabbling ducks and existed on most of the larger Hawaiian islands for the last 3 million years or so – before going extinct around 1000 years ago following the arrival of Polynesian settlers.

Chelychelynechen had an unusually-shaped bill, tall and broad with vertically-oriented nostrils, convergently similar to the beak of a turtle. It would have occupied the same sort of ecological niche as giant tortoises on other islands, filling the role of large herbivore in the absence of mammals.

Bathornis

Bathornis grallator, a flightless bird about 75cm tall (2′6″) from the Late Eocene and Early Oligocene of Midwestern USA (~37-34 mya).

It was originally mistaken for a long-legged vulture (under the name Neocathartes) when first discovered in the 1940s, but later studies have shown it was actually one of the smaller members of the bathornithids – close cousins of the more well-known South American “terror birds”, successfully occupying terrestrial predator niches alongside large carnivorous mammals.