Paleontologists have redescribed Epitornoceras bardisi Using new fossils from the Chigua Formation, researchers have uncovered a mysterious species of ammonite cephalopod that lived in the Devonian Period of Argentina.
Artistic Reproduction of an Ammonite Epitornoceras bardisi During the Middle Devonian. Image courtesy of H. Santiago Druetta / CICTERRA / National University of Córdoba.
Epitornoceras bardisi It lived in the marine environment of the supercontinent Gondwana during the Late Givetian Stage of the Middle Devonian, approximately 383 million years ago.
“During the Early to Middle Devonian, southwestern Gondwana was characterized by a circumpolar marine environment with a remarkable phase of increasing specificity and the near absence of typical Palaeozoic groups (mainly conodonts, graptolites and stromatoporoids),” Dr. Ninon Allaire By the National University of Córdoba and colleagues.
“One of these families is Ammonite They are extremely rare, with only a few reported finds in deposits from the Early Eifelian to Early Frasnian (393 to 383 million years ago) in Bolivia and Argentina.
Epitornoceras bardisi It was first described as a member of the cephalopod genus in 1968. Tornoceras.
The team's new findings suggest that the species should be reclassified into a separate genus. Epitornoceras.
The genus has been recorded from North America, North Africa and Europe, but this is its first record from South America.
“Epitornoceras “It inhabits North Africa, the Rhine-Bohemian basin and the Appalachian basin,” the paleontologists said.
“Their diversification and acquisition of a wide geographic range occurred after the Taganic biotic crisis in the mid-late Givetian.”
“therefore, Epitornoceras Its occurrence in the southernmost part of West Gondwana during the Late Givean is not surprising, given the well-documented pattern of tropical migration into the circumpolar basins following the Taganic biotic crisis.”
New specimens Epitornoceras bardisi From the type area of the Chigua Formation, San Juan Province, Argentina. Image courtesy of Allaire others., doi: 10.5252/geodiversitas2024v46a7.
In this study, the authors examined 10 new specimens. Epitornoceras bardisi It was collected from the top of the Chigua Formation in San Juan Province, Argentina.
The study area is located in the Argentine Precordillera, an intraplate fold-fault zone at the southern edge of the Central Andean foreland basin.
“Epitornoceras “Records from Appalachia, Morocco and Europe indicate that the genus is distributed worldwide and diversified after the Taganic biotic crisis in the mid-late Givetian,” the researchers said.
“Its presence at the southernmost tip of western Gondwana suggests a late Givetian migration from the tropics into the cooler Malvinocossan realm.”
“Despite the presence of ammonites from all over the world in the Argentine Precordillera, the coexisting trilobites are Carmoniaceae Additional endemic genera include Bellenopigue“We confirm that the Malvinoxosan (Malvinocafric) realm is still identifiable as a major biogeographic unit during the Late Givettian of southernmost West Gondwana, based on its typical diagnostic elements.”
Team paper Published in the journal Geodiversitas.
_____
N. Alaïa others2024. Late Givetian (Middle Devonian) ammonoids Epitornoceras Flake, 1902, from Argentina (southwest Gondwana). Geodiversitas 46(7):327-341; doi: 10.5252/geodiversitas2024v46a7
Source: www.sci.news
