#baptornis

[esmaniottoart]

Sketch_Walking With Baptornis.

Pencils, 2019.

[a-dinosaur-a-day]

Baptornis advenus

By José Carlos Cortés on @quetzalcuetzpalin-art​

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Name: Baptornis advenus

Name Meaning: Diving Bird

First Described: 1877

Described By: Marsh

Classification: Dinosauria, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostylia, Ornithothoraces, Euornithes, Ornithuromorpha, Ornithurae, Hesperornithes

Baptornis is our first decidedly in-order Hesperornithine, the group of diving, eventually fully aquatic & flightless almost-birds that so well occupy depictions of Late Cretaceous dinosaurian life. Baptornis is one that was fully aquatic, so not a transitional Hesperornithine - weirdly enough, the ones that show the process from an Ichthyornis-like ancestor to the weird and highly specialized Hesperornis are coming later in the week because I’m bad at scheduling. Baptornis was described a while ago, by Marsh, and this makes it one of the first Mesozoic near-birds described by paleontologists. It was found in the Niobrara Formation of Kansas, and as such, lived in the great Western Interior Seaway of North America, in the Coniacian to Campanian ages of the Late Cretaceous, about 83 or so million years ago. It is known from an extensive amount of material, possibly even more than Hesperornis itself. 

By Scott Reid on @drawingwithdinosaurs

It had a wingspan of about 36 centimeters, and its body length was about 70 centimeters, though the length of its tail is unknown. It had a long and slender head with a slim toothed snout, as well as a long and slender neck, allowing it to dive and grab fish in its mouth. It had a cylindrical body and its wings really weren’t used for much of anything, though its legs were long. It was the smallest Hesperornithine in the Western Interior Seaway, and as such it probably lived in shallower water and fed on smaller fish, such as herring-like fish, and other small ocean foods than its close by relatives. It also had webbed feet, and was very clumsy on land, pushing itself around rather than walking, because its legs would have been tucked into its body and the feet spread out - it might have been able to waddle or hop, more so than Hesperornis, but still not great. 

Sources:

Martyniuk, M. P. 2012. A Field Guide to Mesozoic Birds and other Winged Dinosaurs. Pan Aves; Vernon, New Jersey. 

https://en.wikipedia.org/wiki/Baptornis

Shout out goes to @invisiblecake!

[palaeopedia]

The diving bird, Baptornis (1877)

Phylum : Chordata Class : Aves Order : Hersperornithiformes Family : Baptornithidae Genus : Baptornis Species : B. advenus

Late Cretaceous (83,5 - 80,5 Ma)

1 m long and 5 kg (size)

North America and Northern Europe (map)

The 1 m long Baptornis had lost the ability to fly, possessing only vestigial wings. Unlike its larger relative Hesperornis, the manual bones were not fully reduced, and it seems to have retained a tiny, finger-like stub. Its legs were powerful and the feet were very large with long toes that could not rotate well, allowing the animal to swim and dive at considerable speed. Its foot, altogether, was rather similar to that of a large loon which it also resembled in overall bulk.

Thus the toes of Baptornis were probably webbed as in loons or ducks, rather than lobed as in grebes and Hesperornis: for birds with lobed toes, rotating the toes is necessary to reduce drag when pulling the foot forward for a new stroke. Still, no skin impressions have been found of webs or lobes, leaving the matter open to debate. What is known from fossil skin impression is that the tarsometatarsus was covered by larger scutes in front and smaller scales behind like in loons, rather than all-scaled as in grebes.

Like other Hesperornithes, Baptornis probably had teeth in its beak which allowed it to grab fish and other slippery prey. The skull is still unknown, but some teeth of the right size and shape have been found in the same rocks as Baptornis bones, and these are likely to be from the bird rather than a non-avian theropod dinosaur. Its neck was unusually long, further extending its reach.

The pygostyle was long, high and narrow. The tail thus probably was laterally compressed and served as rudder; a similar adaptation though less extreme is found in today's loons.

As its relatives, the bones of Baptornis were dense, much like in mammals. This helped the animal to dive by reducing its buoyancy. It also made the bones fossilize better, making them more common than those of flying birds like Ichthyornis which, compared to other vertebrate bones, are rare as fossils.