Figure 1.
Location of the Khoratpithecus-bearing localities of Thailand and Myanmar.
a: map of Southeast Asia. b: general map of Myanmar. c: local map of the region of Magway displaying the Irrawaddy Formation outcrops [6] in light grey.
Figure 2.
MFI-K171, holotype mandible of Khoratpithecus ayeyarwadyensis n. sp.
A: lingual view. B: buccal view. C: interpretive drawing of the lingual view. D: interpretive drawing of the buccal view. E: ventral view. F: occlusal view. G: enlarged occlusal view of the tooth row. H: Detailed view of the anterior region displaying alveoli shadows. Scale bars: 5 cm for A–F and I–J and 1 cm for G–H. Abbreviations: cr, crown remnant; r, ramus. I: lingual view displaying roots shadows for P3-M3 and alveoli shadows for incisors and the canine. J: dental row with virtually extracted roots in buccal view.
Table 1.
Mandibular measurements of Khoratpithecus ayeyarwadyensis (in millimeters).
Table 2.
Comparison of the corpora measurements and indices of MFI-K171, TF 6223, and Ouranopithecus macedoniensis.
Figure 3.
Comparison of the symphyseal sections of Khoratpithecus ayeyarwadyensis and selected fossil and extant hominoids.
Khoratpithecus ayeyarwadyensis MFI-K171 (A), Khoratpithecus piriyai TF 6223 (B), Indopithecus giganteus (C), Lufengpithecus lufengensis adult female PA 895 (D1), young male PA 548 (D2) and adult male LC 102 (D3), Sivapithecus sivalensis GSP 9564 (E) and GSP 13875 (F), Ankarapithecus meteai female AS-95-500 (G), six symphyses of male (H) and female (I) Pongo pygmaeus pygmaeus aligned on their centroid. B from [18]; C, E, F, H, I from [20]; D from [21]; G from [37]. Symphyses not to scale. Note that Lufengpithecus lufengensis symphyseal sections are presumably deformed.
Figure 4.
Comparison of the symphysis angulation of MFI-K171 with those of selected living and fossil hominoids.
The angulation (measured between the long axis of the outline and alveolar margin plane and/or the occlusal plane) where obtained from CT-scans (Pongo, Pan, Gorilla, Khoratpithecus piriyai TF 6223, and MFI-K171) and pictures of casts (Indopithecus, Gigantopithecus AMNH 99528 and 39527, Sivapithecus GSP 15000, 9564 and 13875, Lufengpithecus PA 820 and 548, Ankarapithecus). The notation X/Y was used when the symphyseal angulations were measured between the long axis and the alveolar margin on X individuals and between the long axis and the occlusal plane on Y individuals.
Figure 5.
Principal component analysis plots of the elliptic Fourier coefficients of the symphyseal outlines of Khoratpithecus MFI-K171 and TF 6223 and extant hominoids.
Only the outlying individuals are represented for the extant hominoids. For each component, extreme outlines and expressed variance are given.
Table 3.
Dental measurements of Khoratpithecus ayeyarwadyensis (in millimeters).
Figure 6.
MFI 89, upper molar of Khoratpithecus.
A: right M2 MFI89 in occlusal view. B: interpretive drawing of MFI89. C–D: interpretive drawings of Khoratpithecus chiangmuanensis left M2 TF 6176 (mirror image) and right M2 TF 6169. The upper arrows point the valley between the paracone and the protocone which is deviated in MFI89. Scale bar: 1 cm. C–D are not to scale.
Figure 7.
Magnetic polarity stratigraphy of the hominoid section.
A: lithology and stratigraphic position of the sampled levels. B: latitude of the virtual geomagnetic pole vs. stratigraphic position. C: polarity column (black bar: normal polarity zone) and potential correlations with the GPTS of [35].
Figure 8.
Paleomagnetic analyses of the samples from the hominoid section.
A–C: Orthogonal vector diagrams (closed/open symbols correspond to the horizontal/vertical component), stereoplots (crosses: upper hemisphere, circles: lower hemisphere), intensity and step plots for representative samples after thermal and alternating field demagnetization. D: Equal-area stereographic projections of site mean ChRM directions. Open triangle: site mean direction (Declination = 7.3°; Inclination = 23.9°; α95 = 7; k = 23; n = 20), Ellipse: 95% confidence ellipse for mean direction. Solid star: direction derived from the 10-Ma apparent polar wander path. E: Isothermal remanent magnetization (IRM) acquisition curves (normalized values) for two representative samples. F–G: Stepwise thermal demagnetization of the differential IRM components (X, Y, and Z). 99B022A: medium grained sandstone. 99B039A: grey claystone.
Table 4.
Site-mean ChRM directions and associated virtual geomagnetic pole paleolatitude.
Table 5.
Faunal list of the Magway section.
Table 6.
δ13C and δ18O values obtained from six Hipparion (s.l.) specimens from the hominoid section.