Earliest Embrithopod Mammals (Afrotheria, Tethytheria) from the Early Eocene of Morocco: Anatomy, Systematics and Phylogenetic Significance

Geochemical investigation of the taphonomy, stratigraphy, and palaeoecology of the mammals from the Ouled Abdoun Basin (Paleocene-Eocene of Morocco)

“…If it is correct, it would be the stratigraphically youngest mammal recovered in the Ouled Abdoun phosphate series. A stratigraphic origin of S. major from the sillons beds is further supported by its larger size and its more derived morphology with respect to S. minor, and also by the chert content and the selachian assemblage found in its matrix (Gheerbrant et al, 2018(Gheerbrant et al, , 2020. In fact, this species yielded very different Ce/Ce* and Pr/Pr* ratios from the rest of the mammals (see Figure 4d), and when Tukey's pairwise comparison is applied to all these younger taxa it reveals that S. major is significantly different from the rest of the remains (p < 0.05, Table 4), which further supports its younger origin in the phosphate series (i.e., Horizon 1 -late Middle Ypresian).…”

“…The EECO warming is likely also to have driven an evolution to increased size the Ouled Abdoun mammals (e.g., Yans et al, 2014). The embrithopods lineage S. minor-S. major (Gheerbrant et al, 2020) records a significant increase in size during the early-middle Ypresian. Similar size changes are observed between Phosphatherium and Daouitherium, however with much less stratigraphic difference between these taxa as inferred here (Figure 6).…”

“…c) Examples of some of the mammals found in the Ouled Abdoun phosphate series, successively from lowermost to uppermost levels: Eritherium azzouzorum (skull rostrum with teeth in ventral view;Gheerbrant, 2009), the earliest known proboscidean, lower bone bed of bed IIa, Selandian; Phosphatherium escuilliei (skull in ventral view;Gheerbrant et al, 2005), early proboscidean, intercalary beds II/I, early Ypresian; Daouitherium rebouli (lower jaw ML 20269987 in lateral view), the first large proboscidean(Gheerbrant et al, 2002), upper phosphates levels (bed 0? ), middle Ypresian; Stylolophus major (maxillary with teeth;Gheerbrant et al, 2018Gheerbrant et al, , 2020, earliest known embrithopod with S. minor, uppermost phosphates levels, bed 0 or sillons, middle Ypresian.…”

Total evidence time-scaled phylogenetic and biogeographic models for the evolution of sea cows (Sirenia, Afrotheria)

“…The same biogeographic hypothesis can be stated for the other two extant paenungulate orders (Proboscidea and Hyracoidea). The first appearance of the extinct paenungulate order Embrithopoda is in the early Eocene of Morocco ( Gheerbrant et al, 2021 ). The embrithopod group has been phylogenetically placed as the sister of Sirenia to the exclusion of Proboscidea ( Seiffert, 2007 ; Cooper et al, 2014 ), or as the sister of a Sirenia + Proboscidea clade ( Gheerbrant et al, 2021 ).…”

“…The first appearance of the extinct paenungulate order Embrithopoda is in the early Eocene of Morocco ( Gheerbrant et al, 2021 ). The embrithopod group has been phylogenetically placed as the sister of Sirenia to the exclusion of Proboscidea ( Seiffert, 2007 ; Cooper et al, 2014 ), or as the sister of a Sirenia + Proboscidea clade ( Gheerbrant et al, 2021 ). In either case, the geographic signal from all the paenungulate orders seems to indicate that their individual and joint origins were Afro-Arabian, and proximate to the Tethys Sea.…”