Reptilian megafauna of the Paleocene era

[Joseph Fossil]

Around 66 Million years ago, at the end of the Maastrichtian stage of the Late Cretaceous period, an astroid struck what is now the Yucatan Peninsula of Mexico. The subsequent impact and its effects caused the KT mass extinction event. The event wiped out 75% of all life on Earth. This included all the non-avian dinosaurs and most genera of marine reptiles. The end of the event also heralded the beginning of the Cenozoic era with the Paleocene period (66.0-56.0 Million years ago), and the dawn of the age of the mammals (one of the survivors from the Cretaceous Paleocene extinction event). But what most people don't realize is that in large areas of the planet, mammals didn't immediately takeover over the top ecological niches the Non-Avian Dinosaurs left vacant. That is because many surviving reptile groups filled those voids first (albeit briefly). In many parts of the globe, The Paleocene was still the age of the reptiles.

 

https://news.agu.org/press-release/scientists-reconstruct-ancient-impact-that-dwarfs-dinosaur-extinction-blast/

 

A Geologic Time Scale 2004. (2004). Nigeria: Cambridge University Press.

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6842625

 

This was partly due to the fact that the climate of the Paleocene and Eocene was generally hotter than today, which favored Ectothermic reptiles. As a result, these reptiles quickly grew to large body sizes and many filled the voids left vacant by the extinction of the endothermic non-avian theropod dinosaurs. Here is a list of these reptiles which hopefully demonstrates the diversity of these incredible creatures during the Paleocene. Let me know if I forgot any examples.

 

 

North America - Thoracosaurus neocesariensis (Gavialoidea) (Late Cretaceous-Paleocene (70.6-56.0 Million Years ago))

(Note: Thoracosaurus species could grow up to 5 meters (16 feet) in length)

 

Kosmodraco dakotensis (Choristodera) (Paleocene (60.2-56.8 Million Years ago)

(Note: Kosmodraco dakotensis could grow up to 5 meters (16 feet) in length)

 

Kosmodraco magnicornis (Choristodera) (Paleocene (56.8-55 Million Years ago))

 

Champsosaurus gigas (Choristodera) (Paleocene)

(Note: Champsosaurus gigas could grow up to 3 meters (9 feet) in length)

 

Borealosuchus acutidentatus (Crocodylomorpha) (Late Cretaceous-Paleocene (66.0-63.3 Million Years ago))

 

Axestemys splendida (Soft-shell turtle-Trionychidae) (Late Cretaceous-Paleocene)

(Note: Axestemys species could grow up to 2 meters (6 feet) in length)

 

Axestemys montinsana (Soft-shell turtle-Trionychidae) (Late Cretaceous-Paleocene)

(Note: Axestemys species could grow up to 2 meters (6 feet) in length)

 

Adocus onerosus (turtle-Dermatemyidae) (Paleocene)

(Note: Adocus species could grow up to 80 cm. (2 feet) In length)

 

 

 

Europe - Thoracosaurus isorhynchus (Gavialoidea) (Late Cretaceous-Paleocene (70.6-56.0 Million Years ago))

(Note: Thoracosaurus species could grow up to 5 meters (16 feet) in length)

 

 

 

South America - Cerrejonisuchus improcerus (Dyrosaurid) (Mid-Late Paleocene (60-58 Million Years ago))

 

Acherontisuchus guajiraensis (Dyrosaurid) (Mid-Late Paleocene (60-58 Million Years ago))

 

Titanoboa cerrejonensis (Boa snake-Boidae) (Mid-Late Paleocene (60-58 Million Years ago))

(Note: Titanoboa cerrejonensis could grow up to 12.8 meters (42 feet) in length)

 

Carbonemys cofrinii (turtle-Podocnemididae) (Mid-Late Paleocene (60-58 Million Years ago))

 

Cerrejonemys wayuunaiki (turtle-Podocnemididae) (Mid-Late Paleocene (60-58 Million Years ago))

(Note: Cerrejonemys wayuunaiki could have grown to 1 meter (3 feet) in length))

 

Puentemys mushaisaensis (turtle-Bothremydidae) (Mid-Late Paleocene (60-58 Million Years ago))

(Note: Puentemys mushaisaensis could have grown to 1.51 meters (5 feet) in length))

 

 

Africa - Arambourgisuchus khouribgaensis (Dyrosaurid) (Late Paleocene (59-55 Million Years ago))

 

Chenanisuchus lateroculi (Dyrosaurid) (Late Cretaceous-Paleocene)

(Note: Chenanisuchus lateroculi could grow up to 4.5 meters (14 feet) in length)

 

Amananulam sanogoi (aquatic snake-Nigerophiidae) (Paleocene)

 

Acleistochelys maliensis (turtle-Bothremydidae) (Paleocene 61.7-55.8 Million Years ago)

 

 

What do you guys think?

 

[Joseph Fossil]

Also I almost forgot to add the following species to the list:

 

Europe (+) - Boverisuchus sp. (Planocraniidae) (Paleocene (58.7-55.8 Million years ago))

(Note: Boverisuchus species could grow up to 3 meters (9.8 feet) in length)

(Extra info source: http://www.fossilworks.org/cgi-bin/bridge.pl?a=collectionSearch&taxon_no=278987&max_interval=Paleocene&country=Germany&is_real_user=1&basic=yes&type=view&match_subgenera=1)

 

Asia - Asiatosuchus nanlingensis (Crocodilia) (Paleocene (61.7-58.7 Million Years ago))

(Note: Asiatosuchus species could grow up to 4 meters (13 feet) in length)

 

South America (+) - Bretesuchus bonapartei (Sebecidae) (Paleocene (58.7-55.8 Million Years ago))

(Note: Bretesuchus bonapartei could grow up to 4 meters (13 feet) in length)

[Al Dente]

There were also giant birds like Gastornis.

[Joseph Fossil]

5 hours ago, Al Dente said:

There were also giant birds like Gastornis.

 

@Al Dente You're absolutely correct (Birds are technically dinosaurs and members of the Archosaur group). However, for this post I wanted to focus strictly on reptiles like crocodilians, snakes, and turtles.

[Joseph Fossil]

@Al Dente The Paleocene also saw the rise of the famous flightless bird group the penguins. Many of these species like Kumimanu (at 1.77 meters in height) were massive for penguins.