Isotopic paleoecology (δ13C, δ18O) of late Quaternary herbivorous mammal assemblages from southwestern Amazon. (1st January 2021)

• Record Type: Journal Article
• Authors: Asevedo, Lidiane; Ranzi, Alceu; Kalliola, Risto; Pärssinen, Martti; Ruokolainen, Kalle; Cozzuol, Mário Alberto; Nascimento, Ednair Rodrigues do; Negri, Francisco Ricardo; Souza-Filho, Jonas P.; Cherkinsky, Alexander; Trindade Dantas, Mário André
• Is Part Of: Quaternary science reviews. Volume 251(2021)
• Publication Date: 2021-01-01
• Subjects: Pleistocene -- Amazonia -- Megafauna -- Paleodiet -- Stable isotopes -- AMS 14C dating; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2020.106700
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: We report the first radiocarbon datings and carbon (δ 13 C) and oxygen (δ 18 O) stable isotopes data to reconstruct the paleoecology of medium to large herbivorous mammals from late Quaternary of southwestern Amazon (Acre and Rondônia states, Brazil). AMS 14 C dates for Neochoerus sp. (29, 072 - 27, 713 Cal yr BP), Notiomastodon platensis (25, 454 - 24, 884 Cal yr BP) and Eremotherium laurillardi (11, 320 - 11, 131 Cal yr BP) support the Lujanian ages. All fossils have low δ 13 C and δ 18 O isotopic values that suggest C3 -dominated environments from closed canopy forests to wooded savannas, agreeing with paleovegetation reconstitution. Most species were browsers ( pi C3 =100%; Niche breadth, B A =0), where the key species with the largest body mass, N. platensis (∼6, 300 kg) and E. laurillardi (∼3, 500 kg), possibly had a more generalized browser diet in closed-canopies to woodlands. Their diet distinguished from the C3 /C4 generalist Trigodonops lopesi (∼1, 900 kg), which foraged in wooded savannas ( p i C3 =70%; B A =0.72), similarly with its relative Toxodon platensis (∼1, 800 kg) that had a browse-dominated mixed feeder diet ( p i C3 ≥ 84%, B A ≤ 0.38) in Peruvian and Bolivian Amazon localities. Palaeolama major (∼280 kg) was possibly a strictly folivorous within forest canopies, whereas Tapirus sp. (∼250 kg) and Mazama sp. (∼40 kg) were browsers in closed-canopies to woodlands. Holmesina rondoniensis (∼120 kg) was a browser but not restricted, where could also feed on herbaceous from understories in woodlands, and Neochoerus sp. (∼200 kg) feeding predominantly herbaceous plants in wooded savannas ( pi C3 =∼69%; B A =0.75). We estimate that the interspecific competition could have been avoid by different feeding strategies, although more investigations are still needed to better understand their ecological interactions in the habitats of the southwestern Amazon during the late Quaternary. Highlights: AMS 14 C dates support Lujanian ages for the mammal fossils in southwestern Amazon. δ 13 C and δ 18 O data suggest closed canopy forest to wooded savanna habitats. Most species were browsers feeding on leaves/fruits of wood plants ( pi C3 = 100%). Trigodonops lopesi and Neochoerus sp. consumed more proportions of herbaceous plants ( p i C4 = ∼30%). Different feeding strategies and habitat use avoided interspecific competitions.