Marivaux Laurent, Adnet Sylvain, Altamirano-Sierra Ali J, Pujos François, Ramdarshan Anusha, Salas-Gismondi Rodolfo, Tejada-Lara Julia V, Antoine Pierre-Olivier
Laboratoire de Paléontologie, Institut des Sciences de l'Évolution de Montpellier (ISE-M, UMR 5554, CNRS/UM/IRD/EPHE), c.c. 064, Université de Montpellier, F-34095 Montpellier, Cedex 05, France.
Departamento de Paleontología de Vertebrados, Museo de Historia Natural-Universidad Nacional Mayor San Marcos (MUSM), Lima 11, Peru.
Am J Phys Anthropol. 2016 Nov;161(3):478-493. doi: 10.1002/ajpa.23052. Epub 2016 Jul 19.
Undoubted fossil Cebidae have so far been primarily documented from the late middle Miocene of Colombia, the late Miocene of Brazilian Amazonia, the early Miocene of Peruvian Amazonia, and very recently from the earliest Miocene of Panama. The evolutionary history of cebids is far from being well-documented, with notably a complete blank in the record of callitrichine stem lineages until and after the late middle Miocene (Laventan SALMA). Further documenting their evolutionary history is therefore of primary importance.
Recent field efforts in Peruvian Amazonia (Contamana area, Loreto Department) have allowed for the discovery of an early late Miocene (ca. 11 Ma; Mayoan SALMA) fossil primate-bearing locality (CTA-43; Pebas Formation). In this study, we analyze the primate material, which consists of five isolated teeth documenting two distinct Cebidae: Cebus sp., a medium-sized capuchin (Cebinae), and Cebuella sp., a tiny marmoset (Callitrichinae).
Although limited, this new fossil material of platyrrhines contributes to documenting the post-Laventan evolutionary history of cebids, and besides testifies to the earliest occurrences of the modern Cebuella and Cebus/Sapajus lineages in the Neotropics. Regarding the evolutionary history of callitrichine marmosets, the discovery of an 11 Ma-old fossil representative of the modern Cebuella pushes back by at least 6 Ma the age of the Mico/Cebuella divergence currently proposed by molecular biologists (i.e., ca. 4.5 Ma). This also extends back to > 11 Ma BP the divergence between Callithrix and the common ancestor (CA) of Mico/Cebuella, as well as the divergence between the CA of marmosets and Callimico (Goeldi's callitrichine).
This discovery from Peruvian Amazonia implies a deep evolutionary root of the Cebuella lineage in the northwestern part of South America (the modern western Amazon basin), slightly before the recession of the Pebas mega-wetland system (PMWS), ca. 10.5 Ma, and well-before the subsequent establishment of the Amazon drainage system (ca. 9-7 Ma). During the late middle/early late Miocene interval, the PMWS was seemingly not a limiting factor for dispersals and widespread distribution of terrestrial mammals, but it was also likely a source of diversification via a complex patchwork of submerged/emerged lands varying through time.
到目前为止，确凿无疑的卷尾猴科化石主要记录于哥伦比亚中新世中期晚期、巴西亚马孙地区中新世晚期、秘鲁亚马孙地区中新世早期，以及最近发现的巴拿马中新世最早期。卷尾猴科的进化史远未得到充分记录，尤其是在中新世中期晚期（拉文塔期南美大陆哺乳动物阶）及其之后的狨猴亚科干群谱系记录完全空白。因此，进一步记录它们的进化史至关重要。
近期在秘鲁亚马孙地区（洛雷托省孔塔马纳地区）的野外考察发现了一个中新世晚期早期（约1100万年前；马约亚期南美大陆哺乳动物阶）的灵长类化石产地（CTA - 43；佩瓦斯组）。在本研究中，我们分析了灵长类材料，其包括五颗孤立牙齿，记录了两个不同的卷尾猴科物种：僧面猴属的一种中型卷尾猴（僧面猴亚科），以及侏狨属的一种小型狨猴（狨猴亚科）。
尽管有限，但这些新的阔鼻猴类化石材料有助于记录拉文塔期之后卷尾猴科的进化史，并且证明了现代侏狨属和僧面猴属/白脸僧面猴属谱系在新热带界的最早出现。关于狨猴亚科狨猴的进化史，发现一个1100万年前的现代侏狨属化石代表，将分子生物学家目前提出的米科狨属/侏狨属分化时间（即约450万年前）至少向前推了600万年。这也将狨属与米科狨属/侏狨属的共同祖先的分化时间追溯到了超过1100万年前，以及狨猴亚科与卡利米科狨（戈尔迪狨猴亚科）的共同祖先的分化时间。
在秘鲁亚马孙地区的这一发现意味着侏狨属谱系在南美洲西北部（现代亚马孙盆地西部）有着深厚的进化根源，略早于佩瓦斯大湿地系统（PMWS）消退的时间，约1050万年前，且远早于随后亚马孙排水系统的形成（约900 - 700万年前）。在中新世中期晚期/中新世晚期早期期间，佩瓦斯大湿地系统似乎并非陆生哺乳动物扩散和广泛分布的限制因素，但它也可能通过一个随时间变化的复杂的淹没/露出陆地的拼凑区域成为了物种多样化的一个源头。
