Palaehoplophorus

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Palaehoplophorus
Temporal range: Middle-Late Miocene
~16–7  Ma
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cingulata
Family: Chlamyphoridae
Subfamily: Glyptodontinae
Genus: Palaehoplophorus
Ameghino, 1883
Type species
Palaehoplophorus antiquus
Ameghino 1883
Species
  • P. antiquusAmeghino 1883
  • P. meridionalisAmeghino 1904
  • P. pressulusAmeghino 1885
  • P. scalabriniiAmeghino 1883

Palaehoplophorus (also spelled, historically, Palaeohoplophorus) is an extinct genus of glyptodont. It lived from the Middle to the Late Miocene, and its fossilized remains were discovered in South America.

Contents

Description

This animal, like all glyptodonts, had a thick carapace, composed of numerous osteoderm fused together, covering a large part of its body. The plates of its carapace bore a medium-sized, depressed central figure, surrounded by a wrinkled peripheral zone, divided by barely defined furrows and irregular tubercles. Large perforations opened in the furrows around the central figure and between the peripheral figures. The tail was protected by a series of mobile osteoderm rings, presenting a similar ornamentation, and by a terminal straight and cylindrical "tube", formed by contiguous, rounded osteoderms, separated by deep grooves with large perforations, similar to those of the carapace. The terminal and lateral osteoderms were almost identical to each other.

Classification

The genus Palaehoplophorus was first described in 1883 by Florentino Ameghino, based on fossil remains found in Argentina in Middle Miocene terrains. Several species have been attributed to the genus, such as Palaehoplophorus antiquus, P. disjunctus, P. meridionalis, P. pressulus, P. scalabrinii, from the Middle to the Late Miocene. Several of these species may be synonymous with each other.

Palaehoplophorus was identified as an archaic representative of the glyptodonts, notably due to the morphology of its caudal tube, with barely differentiated osteoderms, a characteristic generally considered primitive. The ornamentation of the osteoderms was however rather derived, which tends to confirm that this genus wasn't nested in a basal position of the group. Palaehoplophorus was a member of the tribe Hoplophorini, along with its relatives Hoplophorus and Plohophorus .

Modern cladistic analysis suggests that Palaehoplophorus is more closely related to other glyptodonts with caudal tubes like Doedicurus than to Glyptodon. Cladogram after Barasoain et al. 2022 [1] :

Glyptodonts
Traditional Glyptodontinae

Boreostemma

Glyptotherium

Glyptodon

"Austral clade"

Propalaehoplophorus

Eucinepeltus

Cochlops

Palaehoplophorus

Kelenkura

Eosclerocalyptus

Plohophorus

Pseudohoplophorus

Doedicurinae

Doedicurus

Eleutherocercus

Neosclerocalyptus

Hoplophorini

Hoplophorus

Propanochthus

Panochthus

Bibliography

  1. Barasoain, Daniel; Zurita, Alfredo E.; Croft, Darin A.; Montalvo, Claudia I.; Contreras, Víctor H.; Miño-Boilini, Ángel R.; Tomassini, Rodrigo L. (June 2022). "A New Glyptodont (Xenarthra: Cingulata) from the Late Miocene of Argentina: New Clues About the Oldest Extra-Patagonian Radiation in Southern South America". Journal of Mammalian Evolution. 29 (2): 263–282. doi:10.1007/s10914-021-09599-w. ISSN   1064-7554. S2CID   245945029.

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