Taxonomy as the first step towards conservation: an appraisal on the taxonomy of medium- and large-sized Neotropical mammals in the 21st century

ABSTRACT The Anthropocene brought an accelerated risk of extinction for species across the globe. However, extinction proneness is not even across groups. Past and current events show large-sized mammals at greater extinction risk than smaller ones. For practical reasons, conservation actions tend to focus on the species level; therefore, well-founded species limits are pivotal. Since 2005, the number of known mammal species is about 20% higher but largely due to taxonomic discoveries in small-sized taxa. Here we review the recent taxonomic advances on medium- and large-sized mammals (MLM) from the Neotropics, and discuss misperceptions concerning the taxonomy stability in this group and how this may hinder proper conservation actions. We advocate that apparent taxonomic inertia toward large-sized mammals is partly related to limited systematic inquiry rather than representing an accurate knowledge of their diversity. Fortunately, this scenario has slowly changed in recent years. Linked to integrative analyses that took place during the 21st century, the Neotropical region represents a major example of recent growth in MLM diversity. Taxonomic novelties were found in eight orders of MLM and occurred across taxonomic ranks, from family to subspecies. Most changes comprise subspecies or synonyms elevated to full species, but new taxa of Artiodactyla, Carnivora, Lagomorpha, Pilosa, Primates, Perissodactyla, and large rodents have also been discovered. Recent reshuffles in MLM classification clearly illustrate the risk that bias in taxonomy studies can bring to conservation. Considering the new findings, some species previously labeled as “least concern” for conservation, stand now in some level of threat. This appraisal challenges the misperception of MLM as well-known and shows that taxonomy is a conservation issue.

摘要
人类世（Anthropocene）给全球范围内的物种带来了加速加剧的灭绝风险。然而，物种的灭绝易感性并非在各个类群间均匀分布。过往与当下的观测与研究均表明，体型较大的哺乳动物相较于小型哺乳动物，面临着更高的灭绝风险。出于保护实践的实际需求，相关行动往往以物种为核心实施单元，因此严谨可靠的物种界定标准至关重要。
自2005年以来，全球已知哺乳动物物种的数量增长了约20%，这一增幅在很大程度上源于对小型哺乳类类群的分类学新发现。本文综述了新热带区（Neotropics）内大中型哺乳动物（medium- and large-sized mammals, MLM）近期的分类学研究进展，并探讨了针对该类群分类稳定性的认知误区，以及这些误区可能如何阻碍恰当的保护行动开展。
我们主张，针对大中型哺乳动物的分类学研究看似停滞不前，这在一定程度上与系统性调查研究的匮乏有关，而非意味着我们已准确掌握了它们的物种多样性全貌。所幸近年来这一局面已逐步改观。伴随21世纪以来开展的整合性分类学分析，新热带区成为了大中型哺乳动物多样性研究近期取得突破性进展的典型范例。
研究在8个大中型哺乳动物的类群中均发现了分类学新类群，且涉及从科到亚种的各个分类阶元。多数分类变更涉及将亚种或异名提升为独立物种，但同时也新发现了偶蹄目（Artiodactyla）、食肉目（Carnivora）、兔形目（Lagomorpha）、披毛目（Pilosa）、灵长目（Primates）、奇蹄目（Perissodactyla）以及大型啮齿类的新类群。
近期大中型哺乳动物分类体系的重构清晰地表明，分类学研究中的偏倚可能给保护工作带来实质性风险。结合最新的研究发现，部分此前被列为“无危（least concern）”的物种，如今已面临不同程度的生存威胁。本评估对“大中型哺乳动物已是研究充分的类群”这一认知误区提出了挑战，并阐明了分类学本身便是与保护工作紧密相关的核心议题。