New paper alert, just in time for #FossilFriday! A reevaluation of the #crocodylian fossils from the #Pliocene Otibanda Formation in Papua New Guinea. For a quick summary, check out the thread below 🧵👇 You can read the paper here (contact me if you need a PDF): www.tandfonline.com/doi/full/10.... - ThreadSky

jorgoristevski.bsky.social • 90 days ago

New paper alert, just in time for #FossilFriday! A reevaluation of the #crocodylian fossils from the #Pliocene Otibanda Formation in Papua New Guinea. For a quick summary, check out the thread below 🧵👇

You can read the paper here (contact me if you need a PDF):
https://www.tandfonline.com/doi/full/10.1080/08912963.2024.2429585

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jorgoristevski.bsky.social•90 days ago

When more material is discovered, it may be demonstrated that at least some (if not all!) of the postcranial croc elements from the Otibanda Formation could be assigned to Mekosuchinae.

jorgoristevski.bsky.social•90 days ago

The postcranial elements were more challenging to determine as to which taxon/taxa they may belong, so we provisionally referred to them as Crocodylia incertae sedis. However, some of the postcranial elements are mekosuchine-like in appearance.

jorgoristevski.bsky.social•90 days ago

The conidont (meaning conical) teeth from the Otibanda Formation probably belong to a species of the genus #Crocodylus (which has surviving species today, both in New Guinea and mainland Australia). So, we provisionally referred the conidont teeth as cf. Crocodylus sp. indet.

jorgoristevski.bsky.social•90 days ago

#Sebecosuchia is a group of extinct crocodyliforms that do not have a known fossil record from Australasia. The last known sebecosuchians went extinct in South America by the end of the Miocene. Therefore, we provisionally referred the Otibanda ziphodont teeth as ?Mekosuchinae gen. et sp. indet.

jorgoristevski.bsky.social•90 days ago

Because the ziphodont teeth from Otibanda are similar to those of ziphodont mekosuchines and they are from a time (Pliocene) and location (New Guinea, which shares A LOT of faunal similarities with Australia), it is most likely that the Otibanda ziphodont was a mekosuchine and not a sebecosuchian.

jorgoristevski.bsky.social•90 days ago

At present, there is only one named ziphodont mekosuchine genus - #Quinkana (although Quinkana was not the only ziphodont mekosuchine genus; a different conversation for a different time).

jorgoristevski.bsky.social•90 days ago

Ziphodont crocodylians inhabited mainland Australia for millions of years, and survived well into the Pleistocene. All ziphodont crocs from Australia belong to the now extinct group called #Mekosuchinae.

jorgoristevski.bsky.social•90 days ago

We also attempted to provide a more thorough and updated definition as to what ziphodont dentition is in #Crocodylomorpha (the group that includes all crocodylians and their extinct relatives).

jorgoristevski.bsky.social•90 days ago

The ziphodont teeth were the main focus of our study. #Ziphodonty is a type of dentition that is characterized by labiolingually compressed tooth crowns (i.e., longer than wide tooth crowns) that have serrated carinae (i.e., serrated front and back cutting edges).

jorgoristevski.bsky.social•90 days ago

Fast forward 57 years, I teamed up with my friends & co-authors Ralph Molnar and Adam Yates to finally examine this material in detail. What we found was 8 postcranial elements, 72 non-serrate conidont teeth and 11 #ziphodont teeth. We gave detailed descriptions accompanied by photographs.

jorgoristevski.bsky.social•90 days ago

Intriguingly, Plane (1967) also mentioned of serrated teeth that he stated “can probably be referred to the suborder Sebecosuchia”. Aside from the short paragraph dedicated to the crocodylian fossils, Plane (1967) did not provide detailed descriptions and none of this material was figured either.

jorgoristevski.bsky.social•90 days ago

The crocodylian fossils mainly consist of isolated teeth and several postcranial fragments. Plane (1967) suggested that most of the isolated teeth and the postcranial elements “can probably be referred to the genus Crocodilus” (notice the archaic spelling Crocodilus instead of Crocodylus).

jorgoristevski.bsky.social•90 days ago

The Otibanda Formation in Papua New Guinea is a fossil bearing site that has been dated as Pliocene in age. Back in 1967, Michael D. Plane published the first detailed faunal assessment of the Otibanda Formation where he briefly mentioned of fragmentary crocodylian fossils.

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