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Protogeosuchidae
Topic Started: May 12 2015, 04:07 PM (94 Views)
the dark phoenix
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the dark phoenix of wonderland
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Protogeosuchids: The beginning of a Sly empire

Appearing in the Triassic, these were the weasel crocs before the true weasel crocs which appeared in the Mid-Jurassic and live to the present day. Fossils of these animals appear in Northern South America but strangely no where else in the world. This may be due to competition with other small predators such as lagerpetids and cynodonts. Over time, they pushed the lagerpetids out of their niche and reduced the weasel-like cynodonts to only a few genera. By the Early-Jurassic, they paved the way for their descendants and handed the torch to the next generation.

The fossil skull of the 3 ft long Protogeosuchus benii resembles that of the small prestosuchid Decuriasuchus quartacolonia This places protogeosuchids and geosuchids in with giant predators of the time like Saurosuchus galilei and Prestosuchus chiniquensis. This makes them interesting in that while most other predators where growing larger and more fearsome, these were downsizing and ending up as the banes of any small animal's existence. A fossil from Brazil showing a long tail and well developed digitigrade legs indicate that these animals were fast runners, taking fast prey like insects or small dicynodonts. This same fossil was found in a burrow with a few eggs and a second adult fossil, showing parental behavior and burrowing adaptations.


Scientific Name: Protogeosuchus benii
Meaning: Ben's early earth croc
Common name: Ben's Dawn Geocroc
Age: Carnian-Rhaetian
Diet: Insectivore/Carnivore
Location: Northern South America
Habitat: Fossil plants from around the Burrow Parent's fossil indicate a flood plain with many trees and a dense layer of ferns covering the forest floor.
Description: It resembles its ancestor,†Decuriasuchus quartacolonia. The snout is narrow when looking at it from above. It posses long legs and tail with all from digits being equipped with curved claws for digging and pinning down prey. It is known from two complete skeletons, a skull, eggs, and the possible holotype which is a upper jaw piece(May belong to another genus).
Notes: It's named after its discoverer, a dinosauromorph specialist named Benjamen James who found the holotype specimen and confused it at first for a Subterranean lagerpetid skull piece. later studies noticed it is a new animal related to earlier found geosuchids and thus the group protogeosuchids was erected.

Scientific Name: Benodon braziliensis
Meaning: Ben's Brazilian tooth
Common name: Brazilian Dawn Geocroc
Age: Early Carnian
Diet: Insectivore/Carnivore
Location: Northern South America
Habitat: similar to P. benii
Description: Jaw fragment resembles that of P. benii and its ancestor †Decuriasuchus quartacolonia. Later a complete skull was found and gave us more insight on this animal.
Notes: Once confused for a larger P. benii, it is now reclassified as its own genus. It may be basal to the group as the jaw piece is large for a protogeosuchid and resembles D. quartacolonia more than later protogeosuchids.
Edited by the dark phoenix, May 13 2015, 02:53 AM.
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DK1000
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Fixed some spelling and grammar errors in there, as well as correcting a couple nomenclatural errors (clade names like "lagerpetid", "cynodont", "geosuchid", etc. aren't capitalised, and neither are specific names).

I'm a little confused with the situation regarding the naming of Protogeosuchus benii, because from what I can gather the name Benodon braziliensis would still be the valid name, while P. benii would be a junior synonym. When two names exist for the same species, it is the name given first (the senior synonym) that takes priority and so the second name is sunk into the first (the junior synonym). In this instance, the name B. braziliensis came first, and with no apparent reason for the name to be disused it is therefore the correct name for this taxon. Binomial names can't just be changed on a whim to something more fitting (Basilosaurus can testify to that), so for P. benii to take priority, there has to be a reason for B. braziliensis to be unavailable.

Seeing as how the remains of B. braziliensis are fragmentary, the piece of skull could be regarded as undiagnostic and not able to confidently distinguish it from other taxa, which would make the name B. braziliensis a nomen dubium. P. benii on the hand—known from better better, diagnostic material—would be valid, and while the fragment of "B. braziliensis" could be generally attributed to P. benii, it is not enough to formally synonymise the two and so P. benii holds priority.
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the dark phoenix
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the dark phoenix of wonderland
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Then I'll consider them two different species that may be the same but more material is needed.
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DK1000
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Corrected the nomenclatural errors (clade names were capitalised again).

The situation with the names is still confusing me. If the "Benodon braziliensis" is a nomen nudum, and the jaw fragment the name was attributed to was diagnosed as the holotype of Protogeosuchus benii, then if that specimen was found to be distinct from the other P. benii specimens then the name P. benii could only be used for the jaw fragment whilst the other specimens would require a new name.

Also, if "B. braziliensis" is a nomen nudum and the jaw fragment is the holotype of P. benii, why is it even included as its own distinct taxon? Taxonomically, "B. braziliensis" doesn't exist in this case as the name was not formally published (hence a nomen nudum) and the only specimen has been made the holotype of another species and given a new name.

From what I can gather, if you want to keep the name P. benii safe, have one of the other skeletons be the holotype while the "B. braziliensis" fragment is attributed as a (potential?) synonym while the name remains a nomen nudum. That way if the two are synonymised, P. benii holds priority while if they are separate P. benii and "B. braziliensis" can both exist as (at least for the former) valid species.
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the dark phoenix
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I pulled a megalosaur.

Fossils lump in the "wastbasket taxon" P. benii now getting spread out into their own things.
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