Dental and cranial anatomy of Eritherium azzouzorum from the Paleocene of Morocco, earliest known proboscidean mammal

Abstract

We describe and compare in detail the oldest know proboscidean Eritherium azzouzorum from the Paleocene phosphate beds (early local Thanetian = Selandian, ca. 60 mys) of the Ouled Abdoun basin, Morocco. Eritherium azzouzorum is one of the best and rare species of an extant placental order known before the Eocene. It is documented by most of the dentition and by the skull rostrum. It resembles especially Phosphatherium and Khamsaconus and displays several significant proboscidean synapomorphies, but it is also very primitive. Many primitive characters of Eritherium are found in the earliest known hyracoids and are probable paenungulate traits. Some of its primitive traits such as the bunodont incipiently lophodont molars are noticeably shared with louisinids and early macroscelidids and are remarkable ungulate-like features among Afrotheria. The primitive morphology of Eritherium suggests rapid paenungulate radiation at the beginning of the Tertiary and rapid evolution of the Proboscidea at the beginning of the Ecocene.

The ear region of earliest known elephant relatives: new light on the ancestral morphotype of proboscideans and afrotherians

“…The isolated petrosal described in this study was mentioned by Gheerbrant et al. (), as specimen PM88, but was not described or illustrated. It is associated with other broken elements of the skull of the same individual, including maxillae, parietals and basicranium, all belonging to specimen PM88.…”

“…It is represented by some elements of the skull and most of the dentition (Gheerbrant, ; Gheerbrant et al. ). The isolated petrosal described in this study was mentioned by Gheerbrant et al.…”

“…The maxillae associated with the petrosal of specimen PM88 are confidently identified as Eritherium azzouzorum (see Gheerbrant et al. , plate 2) , and the size and aspect of the bone of the isolated petrosal indicate that they belong to the same individual. This petrosal is partly damaged by two fissures that run across its surface (one on the tympanic surface and one on the cerebellar surface).…”

“…The left petrosal PM88 of Eritherium azzouzorum was found broken and isolated, but in association with several other skull fragments (Gheerbrant et al. ). It was oriented indirectly based on comparisons with the petrosals of Protungulatum (O'Leary, ) and Ocepeia (Gheerbrant et al.…”

Convergence of Afrotherian and Laurasiatherian Ungulate-Like Mammals: First Morphological Evidence from the Paleocene of Morocco

“…Eritherium comes from the same Selandian level in the Ouled Abdoun basin (Morocco) than Abdounodus and Ocepeia , and is the most primitive known proboscidean [ 19 – 20 ]. Abdounodus intriguingly resembles Eritherium in several traits ( Fig 7 ).…”