Retracted: Early hominin biogeography in Island Southeast Asia

Abstract

Island Southeast Asia covers Eurasia's tropical expanse of continental shelf and active subduction zones. Cutting between island landmasses, Wallace's Line separates Sunda and the Eastern Island Arc (the Arc) into distinct tectonic and faunal provinces. West of the line, on Sunda, Java Island yields many fossils of Homo erectus. East of the line, on the Arc, Flores Island provides one skeleton and isolated remains of Homo floresiensis. Luzon Island in the Philippines has another fossil hominin. Sulawesi preserves early hominin archeology. This insular divergence sets up a unique regional context for early hominin dispersal, isolation, and extinction. The evidence is reviewed across three Pleistocene climate periods. Patterns are discussed in relation to the pulse of global sea-level shifts, as well as regional geo-tectonics, catastrophes, stegodon dispersal, and paleogenomics. Several patterns imply evolutionary processes typical of oceanic islands. Early hominins apparently responded to changing island conditions for a million-and-a-half years, likely becoming extinct during the period in which Homo sapiens colonized the region.

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

“…These included large areas of open woodland, indicated by the presence of Stegodon trigonocephalus, an abundance of large bovids (e.g., Bubalus palaeokerabau, Bibos palaeosondaicus), and various cervids and carnivores (e.g., Panthera) 2,29 , and by a pollen record revealing the dominance of sedges, grasses, and ferns, with scattered trees such as Acacia, leaf-flower and Indian albizia 30 . Freshwater marsh and lake-edge habitats, as well as wet grasslands with scattered shrubs, were also found in lower elevations of the landscape, indicated by a variety of aquatic and semi-aquatic vertebrate (Hexaprotodon, tortoise, crocodiles, turtles, fish) and invertebrate species 2,29 . The occurrence of two monkey species, Macaca fascicularis and Trachypithecus cristatus, is a strong indicator for the presence of forested areas in the ecosystem as well 2 .…”

“…Freshwater marsh and lake-edge habitats, as well as wet grasslands with scattered shrubs, were also found in lower elevations of the landscape, indicated by a variety of aquatic and semi-aquatic vertebrate (Hexaprotodon, tortoise, crocodiles, turtles, fish) and invertebrate species 2,29 . The occurrence of two monkey species, Macaca fascicularis and Trachypithecus cristatus, is a strong indicator for the presence of forested areas in the ecosystem as well 2 .…”

“…To these can now be added Meganthropus from Java, formerly suggested to be an ape by some 112,1314, 14 15 but only confidently demonstrated to be so by the comparative analyses presented here. As demonstrated by paleobotanical, paleontological and geochemical proxies 2,[38][39][40] , the Early to Middle Pleistocene palaeoenvironments of Sangiran and Trinil included a variety of mixed and temporally shifting habitats, ranging from open woodland areas hominid specimens were performed using various equipments with the following parameters: 95-kV, 0.04-0.40 µA, 0.17-0.36° of angular step. The final volumes were reconstructed with voxel sizes ranging from 8.3 to 60.0 µm.…”

Paleospecies as cognitive construct: The meme of “Homo floresiensis”

“…Nonetheless, in some papers stressing the uniqueness of the "H. floresiensis" species, the LB1 vault is represented as relatively thick (Baab et al 2009(Baab et al , 2015. Yet other papers emphasizing the same morphological-based species uniqueness (Larick et al 2015) state the reverse: "LB1 exhibits a marked reductive trend in its facial skeleton, with extremely low overall cranial size, a primitive low and anteriorly narrow vault shape with thin cranial bones [our emphasis], a relatively prognathic face, and small teeth [again our emphasis]." Fact checking is in order at this point.…”

Understanding Late Pleistocene human land preference using ecological niche models in an Australasian test case

“…ENMs have been used to assess both biogeographic patterns and species distributions throughout time (Maguire et al, 2015), as well as to find or reconstruct refugia (Waltari et al, 2007;Svenning et al, 2011;Gavin et al, 2014;Shi et al, 2014). Reconstructing refugia using ENM is of great interest to studies of human evolution and dispersal, as refugia have been considered a key element in hominin survival and dispersal (Dennell et al, 2011;Louys and Turner, 2012;Stewart and Stringer, 2012;Larick and Ciochon, 2015;Roberts and Petraglia, 2015;Bacon et al, 2018b). ENMs have been used to successfully identify Pleistocene refugia based on fossil occurrence data and extant environmental data in several plant species (Martínez-Meyer and Peterson, 2006;Gavin et al, 2014).…”