Taxonomic account

The IUCN Red List database lists 106 species covering all NWM orders (i.e. Didelphimorphia, Microbiotheria and Paucituberculata), included in the following Red List Categories (Fig. 1a): 1 (0.9%) Extinct, 2 (1.9%) Critically Endangered (CR), 9 (8.5%) Vulnerable (VU), 7 (6.6%) Near Threatened (NT), 15 (14%) Data Deficient (DD), and 72 (68%) Least Concern (LC).

Of the three NWM orders, Microbiotheria and Paucituberculata have most of their species in NT and VU categories (Fig. 1a), presenting restricted distributions along the Andes, overlapping with four of the Global 200 priority ecoregions (Olson & Dinerstein 2002): the northern Andean Montane Forest, the northern Andean Paramo, the central Andean Yungas, and the Valdivian Temperate Rainforest/Juan Fernández Islands. Three of these ecoregions (i.e. the northern Andean Montane Forest, the central Andean Yungas, and the Valdivian Temperate Rainforests/Juan Fernández Islands) have an estimated conservation status categorised as critical or endangered (CE), while the northern Andean Paramo is relatively stable or intact (RS) (Olson & Dinerstein 2002). Didelphimorphia, the most species-rich and broadly distributed NWM order, has 12 of its species in Threatened or Near Threatened categories, while most species (n = 70; 51%) are listed as LC (Fig. 1b). The ongoing recognition of new species, have already changed these percentages, with several taxa (32 species; 23%) not yet assessed (Fig. 1b; Appendix S1).

The only species considered as Extinct, Cryptonanus ignitus (Díaz, Flores, and Barquez, 2002), was recently synonymized with Cryptonanus chacoensis (Teta & Díaz-Nieto 2019) and should be removed from this category. Only two species are included in the CR category: Monodelphis unistriata and Marmosops handleyi (Fig. 1a,b; Appendix S1). Monodelphis unistriata (Wagner, 1842) is a small marmosine with only two known records from southern Brazil and northeastern Argentina (Pine et al. 2013), which has not been recorded for the past 120 years (Pavan 2016). Marmosops handleyi (Pine, 1981) is a thylamyine species only known from five localities around Valdivia (Colombia), and with an extent of occurrence smaller than 100 km² (Díaz-Nieto et al. 2011, Pérez-Hernandez & Cáceres 2016). Nine species are listed as VU, including three marmosines (Marmosa phaea, Marmosa xerophila, and Monodelphis reigi), three thylamyines (Marmosops juninensis, Marmosops pakaraimae, and Thylamys karimii), and three caenolestids (Caenolestes condorensis, Caenolestes convelatus, and Caenolestes sangay) (Fig. 1a,b; Appendix S1). The taxonomic status of Marmosa phaea Thomas, 1899 was reevaluated by Voss et al. (2020) who found that it presents a wider distribution, from the Colombian Andes to the Amazonian lowlands of northwestern Brazil. Since some species of Marmosa are sympatric and morphologically similar, the name Marmosa phaea was attributed to other taxa, now identified as Marmosa adleri Voss, Giarla, and Jansa, 2021, and Marmosa perplexa Anthony, 1922 (Voss et al. 2021, Voss & Giarla 2021). Therefore, the threat status of Marmosa phaea, as well as the new taxa recently described or revalidated, need to be reevaluated in light of each current species' range. Seven species are listed as NT, including four Thylamyini didelphids (Chacodelphys formosa, Thylamys fenestrae, Thylamys macrurus, and Thylamys velutinus), the microbiotherian Dromiciops gliroides, and two Paucituberculata (Caenolestes caniventer and Rhyncholestes raphanurus). Thylamys fenestrae (Marelli, 1931) was revalidated by Martin (2008, 2009) based on morphometric analysis and morphologic data, but synonymized with Thylamys pallidior (Thomas, 1902) based on molecular data (Giarla et al. 2010) or considered a subspecies of Thylamys pallidior (Palma et al. 2014). Fifteen species are listed as DD, one Didelphini (Philander olrogi), five Marmosini (Marmosa andersoni, Marmosa rubra, Marmosa tyleriana, Monodelphis handleyi, and Monodelphis iheringi), and nine Thylamyini (Cryptonanus agricolai, Cryptonanus guahybae, Cryptonanus unduaviensis, Gracilinanus emiliae, Marmosops cracens, Marmosops creightoni, Marmosops fuscatus, Thylamys tatei, and Thylamys venustus). Philander olrogi Flores, Barquez, and Díaz, 2008 was treated as a synonym of Philander canus by Voss et al. (2018) based on morphologic data. Marmosops cracens (Handley and Gordon, 1979) is now considered a synonym of Marmosops fuscatus (Thomas, 1896) (Díaz-Nieto & Voss 2016). The majority of NWMs are listed as LC, including 70 Didelphimorphia and two Paucituberculata (Caenolestes fuliginosus and Lestoros inca). Of the 70 didelphid species, several have been found to be species complexes and were split into new species, with narrower distributional ranges, including 12 in the genus Marmosa (see below), two in the genus Monodelphis: Monodelphis arlindoi Pavan, Rossi, and Schneider, 2012 and Monodelphis touan (Shaw, 1800) (Pavan et al. 2012); one in the genus Metachirus: Metachirus myosuros (Temminck, 1824) (Voss et al. 2019); five in the genus Philander (Voss et al. 2018), one in the genus Gracilinanus: Gracilinanus peruanus (Tate, 1931) (Semedo et al. 2022), and one in the genus Marmosops: Marmosops woodalli (Pine, 1981) (Ferreira et al. 2020). Within the genus Marmosa, Marmosa adleri and Marmosa nicaraguae Thomas, 1905, now treated as valid and distinct species, were previously considered as part of Marmosa alstoni (Allen, 1900) (Voss et al. 2021); Marmosa rapposa Thomas, 1899 (or its junior synonym Marmosa budini Thomas, 1920) was previously considered as part of Marmosa constantiae Thomas, 1904 (Silva et al. 2019) or Marmosa regina Thomas, 1898 (Voss et al. 2020); Marmosa zeledoni Goldman, 1911 was treated as part of Marmosa mexicana Merriam, 1897 (Rossi et al. 2010); Marmosa macrotarsus (Wagner, 1842) and Marmosa waterhousei (Tomes, 1860) were splitted from the previously recognised Marmosa murina (Linnaeus, 1758) (Voss et al. 2014); Marmosa germana Thomas, 1904; Marmosa jansae Voss and Giarla, 2021; Marmosa parda Tate, 1931 and Marmosa rutteri Thomas, 1924 were part of the old concept of Marmosa regina, which is now a suppressed name under Marmosa isthmica Goldman, 1912 (Voss et al. 2020, Voss & Giarla 2021); and Marmosa isthmica and Marmosa simonsi Thomas, 1899 were part of Marmosa robinsoni Bangs, 1898 (Rossi et al. 2010). Within Philander, Philander nigratus (Thomas, 1923) was part of Philander andersoni (Osgood, 1913) (Voss & Giarla 2020); Philander canus (Osgood, 1913), Philander quica (Temminck, 1824), Philander pebas Voss, Díaz-Nieto, and Jansa, 2018 and Philander melanurus (Thomas, 1899) were part of the wide-distributed Philander opossum (Linnaeus, 1758) (Voss et al. 2018). Recent taxonomic advances, including data from Astúa (2015), Voss (2022), Beck et al. (2022), Astúa et al. (2022), and the Mammal Diversity Database v 1.12 (Mammal Diversity Database 2024) show an increase in living NWMs from 105 (IUCN Red List) to 137 (Astúa et al. 2022), or 135 species (Mammal Diversity Database 2024) (Appendix S2). Major taxonomic changes occurred in small and highly polytypic genera (e.g. Marmosa, Monodelphis, Marmosops), but also in medium-sized and broadly distributed genera (e.g. Philander, Metachirus). These changes affect the conservation status of several species, as available information on some taxa is restricted to forms within their original distribution (see below).

The description of new species, as well as the reevaluation of the taxonomic status of several taxa, especially within Didelphimorphia, has been a common trend for the last 5–10 years, as a result of new research in poorly studied and broadly distributed genera and species (e.g. Cryptonanus, Didelphis, Marmosa, and Metachirus) (e.g. Voss et al. 2018, Fegies et al. 2021). As more revisionary studies are being conducted on widely distributed taxa (e.g. Didelphis albiventris, Metachirus myosuros, and Caluromys spp.) it is expected that new species will be described, old nominal taxa might be revalidated, synonymized or even suppressed (Teta et al. 2022, Chemisquy et al. 2023). These changes will be considered non-genuine according to the IUCN terminology, where a new species originates from the splitting of an already known and previously assessed taxon (IUCN Standards and Petitions Committee 2022). The splitting of known species into new, different ones, has a direct impact on their conservation status, since all parameters evaluated change (Voss et al. 2020, 2021).

Australasian marsupials comprise 265 species in 17 families and four orders (Woinarski & Fisher 2023) a pattern clearly different from NWMs, for which most of its richness has become extinct (Goin & Martin 2022). Comparisons between Australasian and NWMs (Fig. 1b,c) show a higher number of extinct Australian species (n = 17; 6.4% EX), as well as those in threatened categories (CR = 15, 5.7%; EN = 21, 7.9%; VU = 34, 13%) (Woinarski & Fisher 2023). Also, DD and non-assessed species represent a small percentage of Australasian marsupials (n = 4; 1.6%; n = 19, 7.2%) compared to the 15 DD NWM species (11%) and 32 non-assessed species (23%) (Fig. 1b,c). This evidences the recent advances in NWM knowledge, with several species being recently validated, and, as well, the lack of studies on rare or narrowly distributed species, mostly represented in DD category. This difference is likely to increase when more species are recognised within broadly distributed taxa.

Population trends

The population trend is unknown for more than half of the species listed (n = 82; 60%), with 34 species (25%) considered stable, 30 species (22%) with decreasing trends, and only three species (2.2%), Didelphis virginiana, Monodelphis domestica, and Monodelphis kunsi, with increasing trends (Appendix S1). Of the 105 species with IUCN assessments (excluding Cryptonanus ignitus), 45 have unknown population trends, with three of them (i.e. Gracilinanus agilis, Gracilinanus microtarsus, and Marmosops incanus) considered stable by the WWF Living Planet Report (2022), Astúa (2015; only the last one), and Rossi and Leiner (2022, 2023; only the first one). Population trends have not been formally evaluated for 43 species, representing 31% of the currently recognised richness (Astúa et al. 2022), with only one considered stable (Philander quica) (Appendix S1). Of the species in which populations are decreasing, all four Caluromyinae are included, one Didelphini, seven Marmosini, 14 Thylamyini (most of them in the genus Thylamys), Dromiciops gliroides, and three Paucituberculata (Caenolestes caniventer, Caenolestes convelatus, and Rhyncholestes raphanurus) (Appendix S1). Stable populations were described for nine Didelphini (most of them in the genus Didelphis), 12 Marmosini (most of them in the genus Marmosa), Metachirus nudicaudatus, 12 Thylamyini (most of them in the genus Marmosops) (Appendix S1). Unknown population trends were recorded for 12 Didelphini (most of them in the genus Philander), 36 Marmosini (most of them in the genus Monodelphis), 25 Thylamyini (most of them in the genus Marmosops), Metachirus myosuros, Glironia venusta, Hyladelphys kalinowskii, and four Paucituberculata (Appendix S1).

Population dynamics in NWM are poorly known, and only a few species have been studied. In their latest review, Gentile et al. (2022) list studies on three Caluromyinae (two Caluromys and Caluromysiops irrupta), nine Marmosini (four Marmosa, four Monodelphis, and Tlacuatzin canescens), six Didelphini (four Didelphis and two Philander), one Metachirini (Metachirus myosuros), and six Thylamyini (four Marmosops and two Thylamys). Most of these studies (>50%) were carried out in the Atlantic Forest of Brazil, also showing a strong bias towards tropical species of forest environments (Gentile et al. 2022, WWF Living Planet Report 2022). However, some data was also reported for open area inhabitants in the WWF Report (2022), including population trends for the species Monodelphis domestica (Braga et al. 2016) and Monodelphis kunsi (AES Tietê 2017), which although based on short-time periods (2–4 years), showed an increase in abundance for both species (Appendix S1).

Apart from these works, Albanese (2010) studied the population ecology of Thylamys pallidior in the Monte desert of Argentina, González-Chávez et al. (2019) the population trends in Caenolestes fuliginosus in central Colombia, and several studies have dealt with the population dynamics (but no overall trends) of Dromiciops gliroides in southern Argentina (Rodríguez-Cabal et al. 2008, Balazote Oliver et al. 2017) and Chile (Fontúrbel et al. 2010, Celis-Diez et al. 2012). Comparisons show Microbiotheria to be one of the best-studied groups of NWMs, despite its limited distribution. Didelphid species living in open areas or extra-tropical environments are poorly represented taxonomically, and their population dynamics are poorly studied. A similar pattern was found in Paucituberculata, with three of seven species with some information available.

Changes to our knowledge of population trends and other aspects of species biology are likely to change when species are reassessed, especially taking into account the current taxonomic changes. For example, Ferreira et al. (2015) reported the population dynamics of Metachirus nudicaudatus from the Atlantic Forest ecoregion of Brazil, but these specimens are now treated as Metachirus myosuros (Astúa et al. 2022, Voss 2022). The same is true for the recent split of Philander opossum (see Voss 2022), for which population studies throughout their range need to be reassessed. Also, several studies have documented semelparity or partial semelparity as part of the reproductive traits of some NWMs, influencing their population trends in the short term and their potential susceptibility to different threats (e.g. fire) (Mendonça et al. 2015, Rossi & Leiner 2023). Although semelparity or partial semelparity is not a common reproductive pattern of NWMs, it has been documented in two very distinct tribes (i.e. Marmosini and Thylamyini) and three genera (i.e. Gracilinanus, Marmosa, and Monodelphis), indicating it could be more widespread than previously thought. Other population studies (e.g. Marmosops incanus, Zangrandi 2011) show that some species of NWMs are highly seasonal, which could impact their long-term population persistence under different disturbances and climate change (Sergio et al. 2018). However, the magnitude and severity of the disturbance may lead to population crashes as observed by Fisher et al. (2014) and Mendonça et al. (2015).

Threats

Only 32 species have identified threats in their current IUCN assessments. However, habitat loss through fragmentation and/or land conversion was described as a possible threat for most species (Fig. 2). We identified 32 species for which ecosystem conversion and degradation represent the main threats (Fig. 2). Of these, small-holder farming (n = 15), agro-industry farming (n = 13), small-holder grazing, ranching, farming, or plantations (n = 9), and housing and urban areas (n = 9) are the main identified threats. However, many species (n = 16) present unknown/unrecorded motivations for native habitat loss or conversion (Fig. 2).

When threats were analysed in detail with the proposed classification and other sources of information were included (e.g. Astúa 2015, Table 1), the category ‘No major threats’ was identified for 69 species, of which 26 species included a conditional threat in the form of ‘No threats are known for this species, although/but…’ and reported that habitat loss in different forms (e.g. deforestation and agriculture) represents possible threats. Of the 61 species in which ‘Habitat loss, fragmentation, and conversion’ were identified as the main threats, 35 had the sub-category ‘deforestation and/or logging’, and 34 had ‘agriculture (including coca plantations)’ as the main threat, 20 species shared ‘deforestation and/or logging’ and ‘agriculture’ as their main threats (Table 1). Other threats were identified for 14 species with ‘agriculture (including coca plantations)’ as their main threat: 10 of them including ‘urbanization and different types of settlements’, six including ‘cattle grazing’, and five including ‘oil, gas and mining’. ‘Urbanization and different types of settlements’ were listed as a threat for 10 species, always considered within the main category of ‘Habitat loss, fragmentation, and conversion’ (Table 1).

Considering the species Red List categories, CR species (n = 2) have ‘Habitat loss, fragmentation, and conversion’ as their main threat; VU species (n = 9) have also ‘Habitat loss, fragmentation, and conversion’ as their main threat, with ‘agriculture (including coca plantations)’ as the main sub-threat category affecting seven species; NT species (n = 7) have ‘Habitat loss, fragmentation, and conversion’ as their main threat, with ‘deforestation and/or logging’ and ‘agriculture (including coca plantations)’ as the main sub-threat categories; DD taxa (n = 15) present three species with unknown threats, four species with no major threats (one conditional with habitat loss, fragmentation, and conversion), and eight species with ‘Habitat loss, fragmentation, and conversion’ as their main threat. For species within this category, ‘agriculture (including coca plantations)’ was identified as the main sub-threat affecting almost half of the species (n = 7). Within the LC category (n = 72), 65 species present no major threats (of which 26 species show conditional threats with habitat loss, fragmentation, and conversion), 32 species present ‘Habitat loss, fragmentation, and conversion’ as their main threat, with ‘deforestation and/or logging’ and ‘agriculture (includes coca plantations)’ as their main sub-threat categories (n = 19 and n = 14, respectively; Table 1). ‘Human consumption’ was identified as a threat for only the two black-eared opossums Didelphis aurita and Didelphis marsupialis; ‘Hunt for fur’ was identified as a threat also for the black-eared opossum Didelphis aurita, and the water opossum Chironectes minimus; ‘Introduced species’ was identified as a threat for the grey mouse opossum Tlacuatzin canescens (Table 1). ‘Habitat loss, fragmentation, and conversion’ was identified exclusively as the main threat for 37 species of Didelphimorphia (32 Didelphinae, 4 Caluromyinae, and Glironia venusta), the Microbiotheria Dromiciops gliroides, and four species of Paucituberculata (three in the genus Caenolestes and Rhyncholestes raphanurus) (Table 1). No major threats were conditionally identified for 67 Didelphimorphians (62 Didelphinae, four Caluromyinae and Hyladelphys kalinowskii), and two Paucituberculata species (Caenolestes fuliginosus and Lestoros inca), including 14 Didelphini, 24 Marmosini, Metachirus nudicaudatus, and 23 Thylamyini species (Table 1).

The majority of NWMs live in tropical and subtropical biomes, including moist broadleaf forests, tropical and subtropical savannas, and shrublands (Goin & Martin 2022), with higher species richness in South America, concentrated in southern Peru and surrounding areas in northwestern Bolivia and western Amazonia, southeastern Brazil, and central Colombia (Martin et al. 2021). These areas comprise distinct ecoregions (sensu Dinerstein et al. 2017) such as Southwestern Amazonian moist forests, Bolivian Yungas, Cordillera Oriental montane forests, and Alto Paraná Atlantic forest, some of them identified as key Neotropical regions for the conservation of terrestrial vertebrates by Loyola et al. (2009).

When threats were analysed in detail, most species appeared to have no direct threats (e.g. consumption and hunting), but all assessments, explicitly or implicitly, pointed at different forms of habitat degradation (e.g. deforestation and agriculture) and fragmentation as important indirect threats to NWMs (Table 1). Studies show that some marsupials move throughout most of the habitats available to them (Pires & Fernandez 1999, Passamani & Fernández 2011), and are highly resistant to habitat fragmentation (Passamani & Fernández 2011). However, these studies are geographically restricted to the Atlantic Forest of southeastern Brazil, or their ecotone with the Cerrado (Machado et al. 2021), and there is scarce information on how fragmentation affects species in other ecoregions (e.g. Southwestern Amazon moist forests, Bolivian Yungas, and Northern Andean montane forests), especially in areas with high anthropic pressure and deforestation.

Research needed

We identified Research needed (combining IUCN assessments with other sources like Astúa 2015) for 85 species (62%), included in five, non-excluding categories: ‘Taxonomy’, with nine species; ‘Life History and Ecology’ with 75 species; ‘Population size, Distribution, and Trends’ with 80 species; ‘Threats’ with 78 species; and ‘Actions’ with two species (Table 2). At the ordinal level, more than 70% of the species of the order Didelphimorphia need information on any of the five categories, with ‘Population size, Distribution and Trends’ (69%), ‘Threats’ (66%) and ‘Life History and Ecology’ (63%) showing the highest values. All Paucituberculata species need more information on ‘Life History and Ecology’ and ‘Population size, Distribution and Trends’, while all species in this order need information on ‘Threats’ (Table 2). The microbiotherian Dromiciops gliroides needs information on ‘Life History and Ecology’ and ‘Threats’ according to IUCN, although recent work has substantially increased our knowledge of this species, especially regarding aspects of its natural history (e.g. Abarzúa et al. 2023) and spatial ecology and threats (e.g. González-Ancín et al. 2021, Fernández et al. 2022). Although considered as a single species by many authors (Valladares-Gómez et al. 2017, Martin 2018, Suárez-Villota et al. 2018), Quintero-Galvis et al. (2021) presented molecular evidence supporting two species: Dromiciops gliroides in the southern part of the distribution, and Dromiciops bozinovici in the northern part. If the second species is considered valid, it might be experiencing more immediate threat than Dromiciops gliroides due to the dramatic native forest conversion to exotic tree plantations and the expansion of urban areas.

At the subfamilial level within Didelphimorphia, most members of Didelphinae and Glironia venusta (Glironiinae) need information on ‘Life History and Ecology’, ‘Population size, Distribution and Trends’, and ‘Threats’, while Hyladelphys kalinowskii needs information on ‘Taxonomy’ and ‘Population size, Distribution and Trends’. There is no information on research needed for Caluromyinae, a subfamily that includes four species (Table 2).

At the tribal level within Didelphinae, information is needed for 75% of the species of each tribe for almost all five categories listed except for ‘Actions’, with the majority needing information on ‘Population size, Distribution and Trends’ (71%) and ‘Threats’ (69%) (Table 2). Didelphini presents information on Research need for seven species (44%), Marmosini for 33 species (79%), Metachirini for 1 species (100%), and Thylamyini for 34 species (83%) (Table 2).

Of the 137 recognised species (Astúa et al. 2022), 69 (50%) species have no identified research needed, of which 32 (46%) have not been assessed by the IUCN, and 37 (54%) have assessments without identified research needed. The latter group comprises species that appear relatively common, moderately to well-known, and with broad distributions (e.g. Didelphis spp.), which might lead to the perception that no information is needed about them. However, available information for most of these species come from well studied populations in small areas of their range (e.g. Caluromys in French Guiana, Didelphis, Marmosa, and Marmosops from the Atlantic Forest).

The information presented and analysed above accounts for 77% of NWM species, with unknown population trends and research needed for more than half of the species. The lack of data for a large number of species in the main categories analysed, together with the outdated nature of some of these datasets, posed limitations on the outcomes of our study. We know so little about the ecology of the majority of NWM species, that revisionary work will inevitably generate more data deficient (DD) or even threatened species (endangered, EN; vulnerable, VU), since several recently delimited taxa have been shown to present restricted distributional ranges (e.g. Pavan et al. 2012). These data highlight the need for overcoming the Linnean and Wallacean shortfalls for most NWMs in time to preserve their habitats, and this becomes even more critical in the face of future climatic changes. Although climate change projections from different sources show contrasting views of how South American biomes will be impacted (Salazar et al. 2007, Lyra et al. 2016, Santos Pereira et al. 2017, Anjos et al. 2021), land conversion and especially deforestation will change ecosystem architecture, affecting marsupials by reducing their ‘optimal’ habitats (Martin et al. 2022). Fire has also been identified as an important source of ‘habitat loss, fragmentation and conversion’ (following the terminology used in this study), especially in semiarid ecosystems (Miranda et al. 2002, Mendonça et al. 2015, Giorgis et al. 2021), and has been shown to impact NWM differently (Martin et al. 2021, Rossi & Leiner 2023).

Studying NWM taxonomy, systematics, biogeography, and how ecological features could be applied to less studied, sister species, will be crucial for a rapid assessment of poorly known species, but this information should be precisely stated. Because it is an almost impossible task to study all species, we should try to find ways to extrapolate broad-scale information to poorly known species within speciose genera (e.g. Marmosops, Marmosa), and concentrate on monotypic genera (e.g. Chacodelphys formosa and Hyladelphys kalinowskii), geographically restricted species (e.g. Caenolestes condorensis, Marmosa andersoni) or those living in unique environments within a genus (e.g. Cryptonanus chacoensis, Thylamys macrurus).

The IUCN Red List database only provides assessments for 106 species of NWM, while the currently accepted number includes 135–137 species (Patterson 2015, Astúa et al. 2022, Beck et al. 2022, Voss 2022). This means that ca. 23% of all the known species are lacking an assessment and proper distribution maps. Our analyses also showed that there is a need for more information on NWM, as research needed was identified for 65 out of 106 species, plus the 32 (53%) species not assessed by the IUCN. This is likely to increase when the recently described or delimited taxa present their own assessments. The ecology of several species with large distributions are only known from scattered parts of their range (e.g. Caluromys philander, Julien-Laferrière & Atramentowicz 1990), and it would be crucial to have information throughout their distribution. Also, many charismatic or large-sized species have been thoroughly studied (e.g. Dromiciops gliroides, Didelphis albiventris, and Marmosa robinsoni), but many of their narrowly distributed counterparts are poorly known (e.g. Didelphis pernigra and Marmosa isthmica). This is critical from a conservation point of view, as many analyses rely on IUCN data to provide accurate information on distribution trends and conservation priorities (Martin et al. 2021).