New Stratigraphic Data from the Erlian Basin: Implications for the Division, Correlation, and Definition of Paleogene Lithological Units In Nei Mongol (Inner Mongolia)

New Material of Eocene Helaletidae (Perissodactyla, Tapiroidea) from the Irdin Manha Formation of the Erlian Basin, Inner Mongolia, China and Comments on Related Localities of the Huheboerhe Area

“…Furthermore, the upper cheek teeth of Teleolophus are obviously distinguished from those of "Helaletes" mongo-liensis in having P2-4 with a protoloph joining the equally developed metaloph a short distance before its lingual end (hypocone), and M1-3 with protoloph, paracone, and metaloph forming an inverted "U" and a metacone greatly reduced. Last, the earliest known deperetellid is from the Arshantan, earlier than Irdinmanhan "Helaletes" mongoliensis (Radinsky, 1965a;Meng et al, 2007;Wang et al, 2010). As a result, we are skeptical of considering "Helaletes" mongoliensis the most primitive member of the family Depetellidae, and the main reason for erecting the new genus "Irdinolophus" is not tenable.…”

“…839) at Camp Margetts; both were collected by CAE in 1930. Recent works have clarified that the Camp Margetts site was near the Duheminboerhe locality, and the "Houldjin gravels" and "Irdin Manha" beds in the Camp Margetts area are considered equivalent to the Irdin Manha Formation and Arshanto Formation, respectively (Meng et al, 2007;Sun et al, 2009;Wang et al, 2010;Wang et al, 2012). Nevertheless, reexamining the original CAE field notes and specimens, we found that the type specimen of P. fissus was actually from the Irdin Manha Formation.…”

“…Based on the sketches of sections in CAE field books and lithological characters, Meng (1990) first correctly pointed out that "Camp Margetts" was located in Duheminboerhe, and the localities identified in the field books as 6 miles west, 7 miles west and southwest, and 10 miles southwest of "Camp Margetts" were located along the Huheboerhe escarpment. After more detailed fieldwork in recent years, Meng et al (2007) and Wang et al (2010Wang et al ( , 2012 further demonstrated that the locality 6 miles west of Camp Margetts is Nuhetingboerhe, that 7 miles southwest of Camp Margetts is Wulanboerhe, and that 10 miles southwest of Camp Margetts is Huheboerhe, while the locality 5 miles east of Camp Margetts (described as an "overnight camp" in the field books) is Daoteyin Obo. Meng et al (2007) also considered the locality 7 miles southwest to be the same as that 7 miles west.…”

“…After more detailed fieldwork in recent years, Meng et al (2007) and Wang et al (2010Wang et al ( , 2012 further demonstrated that the locality 6 miles west of Camp Margetts is Nuhetingboerhe, that 7 miles southwest of Camp Margetts is Wulanboerhe, and that 10 miles southwest of Camp Margetts is Huheboerhe, while the locality 5 miles east of Camp Margetts (described as an "overnight camp" in the field books) is Daoteyin Obo. Meng et al (2007) also considered the locality 7 miles southwest to be the same as that 7 miles west. By contrast, Wang et al (2010Wang et al ( , 2012 considered the locality 7 miles southwest and the one described as 7 miles west of Camp Margetts should be different localities, the former Wulanboerhe, and the latter a place in the north of Wu lanboerhe.…”

New Craniodental Materials of Litolophus gobiensis (Perissodactyla, “Eomoropidae”) from Inner Mongolia, China, and Phylogenetic Analyses of Eocene Chalicotheres

“…The field investigation clarified some uncertainties about the stratigraphy of the region as raised by Radinsky (1964b) and demonstrated that Nuhetingboerhe is the same area where the holotype of Litolophus gobiensis was found. The recent study also shows that the strata containing the Litolophus specimens are the basal Arshanto Formation rather than the Irdin Manha Formation and are of Early Eocene in age (Meng et al, 2007b;Sun et al, 2009). All materials were collected from the ''chalicothere pit'' quarry during several field seasons in the last few years.…”