Evidence for increased hominid diversity in the Early to Middle Pleistocene of Indonesia

Abstract

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A distinguishing feature of Pongo upper molars and its implications for the taxonomic identification of isolated hominid teeth from the Pleistocene of Asia

“…= 10). Furthermore, it should be noted that our Meganthropus sample is represented by Trinil 11620 and Trinil 11621, specimens with controversial affinities and that have been previously attributed to other taxa (see above, and Zanolli et al, ). Additional details of the fossil specimens used in this study are provided in Table S1.…”

“…Previous studies of tooth microstructure and dental tissue proportions have identified additional dental features that differ between pongines and hominins, such as the equal reduction of enamel and dentine in Pongo , but preferential loss of dentine in Homo during the process of tooth size reduction in these two groups (Grine & Franzen, ; Smith et al, ; with the exception of Neanderthals, see Olejniczak, Smith, Feeney, et al, ). Pongo molars also differ from those of humans in having lower dentine horns and an overall different shape of the EDJ with broader crowns, broad, and shallow dentinal intercuspal furrow pattern and less medially placed lingual dentine tips (Olejniczak, Martin, & Ulhaas, ; Olejniczak, Smith, Wang, et al, ; Smith et al, ; Zanolli et al, ). In addition, when only fossil individuals were considered, Smith et al () found that enamel has a more uniform distribution across the enamel cap in fossil Pongo than in H. erectus , although relative enamel thickness values overlap substantially in the two taxa (Smith et al, ).…”

“…Hominid biogeography in Asia during the Pleistocene is characterized by a complex scenario where at least four genera— Pongo , Homo , Gigantopithecus , and Meganthropus —coexisted in mainland and island Asia (Ciochon, ; Zanolli et al, ). Although orangutans are today restricted to Borneo ( Pongo pygmaeus ) and northern Sumatra ( Pongo abelii and Pongo tapanuliensis ; Nater et al, ), they were widely distributed in China, Vietnam, Thailand, Laos, Cambodia, Peninsular Malaysia, Borneo, Sumatra, and Java during the Pleistocene (Bacon et al, ; Bacon & Long, , ; Ciochon, Olsen, & James, ; Groves, ; Harrison, , ; Harrison, Jin, Zhang, & Wang, ; Harrison, Krigbaum, & Manser, ; Hooijer, ; Ibrahim et al, ; Kaifu, Fachroel, & Baba, ; Nisbett & Ciochon, ; Olsen & Ciochon, ; Schwartz, Long, Cuong, Kha, & Tattersall, , ; Spehar et al, ; Wang et al, ; Zhao, Wang, Jin, Qin, & Pan, ).…”

“…Several dental remains from Sangiran Dome and Trinil in Java, dated to the Early or Middle Pleistocene have been attributed to Homo erectus, Meganthropus palaeojavanicus , or Pongo sp. (Antón, ; de Vos, ; Harrison et al, , ; Hooijer, ; Smith et al, ; Tyler, ; von Koenigswald, ; Zanolli et al, ; Zanolli, Grine, Kullmer, Schrenk, & Macchiarelli, ), with a few authors even suggesting morphological affinities with Homo habilis , Paranthropus robustus , Australopithecus africanus , and Pan sp. (e.g., Tyler, , ).…”

“…(e.g., Tyler, , ). In particular, the taxonomic affinities of the following specimens from Southeast Asia have been the subject of intense debate among scholars: Trinil 11620 and Trinil 11621 from Trinil, Indonesia, and SMF‐8855, SMF‐8864, SMF‐8865, SMF‐8879, SMF‐8898, SMF‐100055, S5, S6a, S7‐9, S7‐20, S7‐53, S7‐62, S7‐64, S7‐65, and S7‐76 from Sangiran, Indonesia (reviewed in Smith et al, ; Zanolli et al, ).…”