Taxonomic assessment, conservation status, and future perspectives for New World Marsupials

New World Marsupials (NWMs) comprise over 135 species ranging from Patagonia (Argentina) to northern North America, classified within the orders Didelphimorphia, Microbiotheria and Paucituberculata. This study examines recent taxonomic revisions and conservation priorities for NWMs, based on the IUCN Red List assessments and current literature. NWMs are included in the following IUCN Red List categories: 2 (1.5%) Critically Endangered (CR), 9 (6.6%) Vulnerable (VU), 7 (5.1%) Near Threatened (NT), 15 (11%) Data Deficient (DD), and 72 (53%) Least Concern (LC), with 32 (23%) species awaiting formal assessments. Population trends remain unknown for more than half of the 137 species (n = 82; 60%), with 34 stable species (25%), 30 declining (22%), and only three showing increasing trends (2.2%). Of the 105 IUCN assessed species, 45 (43%) have unknown population trends. Identified threats for assessed species (n = 32) include ecosystem conversion and degradation as the main threats, with habitat loss through fragmentation and/or land conversion potentially affecting 26 additional species. When analysed in detail with the proposed classification ‘Habitat loss, fragmentation, and conversion’ were identified as the main threat to 61 species. Research needs were identified for 85 species (62%), across five categories: Taxonomy (9 species), Life History and Ecology (75 species), Population size, Distribution and Trends (80 species), Threats (78 species), and Actions (2 species). We propose four key steps to enhance the conservation of NWMs: 1) update assessments to include all valid species, 2) identify priority areas for NWM conservation, 3) encourage research collaboration, and 4) integrate data into conservation strategies at various spatial and political scales.