Introduction

Ecosystems around the world are losing biodiversity at an accelerated rate as a result of habitat loss, overexploitation, introduction of invasive species, and climate change (^{Naeem et al. 2012}; ^{Johnson et al. 2017}; ^{Ceballos et al. 2020}). This loss of biodiversity has negative repercussions on ecological processes and the services they provide to human populations (^{Brodie et al. 2021}). For example, the loss of primate species can have detrimental effects on seed dispersal and consequently on forest regeneration and tree community structure (^{Gardner et al. 2019}). Knowing the diversity of mammal species in a given area can not only help to identify the impact of anthropogenic activities on it and its natural habitats (^{Rocha et al. 2014}; ^{González-Maya et al. 2016}; ^{Brodie et al. 2021}), but also contributes to the creation of baseline studies on different biological aspects (e. g., biogeography, ecology), environmental education, disease prevention or control, and more. From this arises the importance and need to generate updated lists of mammal species at any geographical level, but especially in high diversity areas.

Costa Rica, located in Central America, is a small country with a land area of approximately 51,100 km², yet it is among the 20 most diverse countries in the world (^{Obando 2002}; ^{Kappelle 2016}). Previous work has described a high richness and functional diversity of mammals (^{González-Maya et al. 2015}; ²⁰¹⁶) that results from its geographical location and geological history (^{Janzen 1991}), and a complex biogeographic history as land bridge and barrier for different groups of mammals that originated in the north and south of the American continent, giving rise to a species composition with origins in both hemispheres (^{Carrillo et al. 2010}; ^{Rodríguez-Herrera et al. 2014}a; ^{Wilson et al. 2014}; ^{González-Maya et al. 2016}).

Since ^{Rodríguez-Herrera et al. (2014}a) mammal’s list, where 249 species were reported for the country, there have been changes in the number of species and their taxonomy. This is remarkable, given that information about mammals in the country has been collected for more than 150 years (^{Rodríguez-Herrera et al. 2005}, ^2014b). The ongoing effort to document the mammalian community of Costa Rica has resulted in several updates to the list (e. g., ^{Wilson 1983}; ^{Rodríguez and Chinchilla 1996}; ^{Rodríguez-Herrera et al. 2002}; ^{Rodríguez-Herrera et al. 2014}a), such that it reflects current taxonomic and systematic classifications (e. g., ^{Pérez Consuegra and Vázquez-Domínguez 2015}; ^{Lim et al. 2020}), accounts for new records and species descriptions (e. g.^{Woodman and Timm 2017}; ^{Salas-Solano et al. 2020}; ^{Villalobos-Chaves et al. 2018}), and changes in distribution range extensions (e .g., ^{González-Maya et al. 2017}; ^{Ramírez-Fernández et al. 2020}). The continued addition of mammal species to the list over the years reflects increased efforts on biological research in the country. This study presents an updated list of the mammals of Costa Rica, including notes on their global and local conservation status.

Materials and methods

This updated list of the mammals of Costa Rica was based on the list of ^{Rodríguez-Herrera et al. (2014}a), compared and matched with the most updated taxonomic review made for the class Mammalia in the Mammal Diversity Database (^{MDD 2022}), from where the original sources were obtained and consulted. Comments on species taxonomic changes and new additions to the list were provided according to a bibliographic review for the taxa differing between both lists. For changes in the total number of species and species by order, we reviewed previous species lists for the country (^{Frantzius 1869}; ^{Alfaro 1897}; ^{Harris 1943}; ^{Goodwin 1946}; ^{Wilson 1983}; ^{Rodríguez and Chinchilla 1996}; ^{Rodríguez-Herrera et al. 2002}; ^{Rodríguez-Herrera et al. 2014}a). Information on the global conservation status of each species was compilated from the latest International Union for Conservation of Nature Red List assessment (^{IUCN 2022}), and the national conservation status according to Costa Rican environmental authorities (^{SINAC 2017}). Common names, and the phylogenetic order of the different orders, families, subfamilies and tribes follows the most recent publication of the Handbook of the Mammals of the World series (^{Mittermeier et al. 2013}; ^{Wilson et al. 2016}, ²⁰¹⁷; ^{Wilson and Mittermeier 2009}, ²⁰¹¹, ²⁰¹⁴, ²⁰¹⁵, ²⁰¹⁸, ²⁰¹⁹), with genera and species listed in alphabetical order.

Results

Species and family richness. In this study we report a total of 256 extant mammal species for Costa Rica, increasing the number of species by seven according to the last list published (^{Rodríguez-Herrera et al. 2014}a; Figure 1). The order Chiroptera accounts for almost half (46 %) of the total number of species documented in Costa Rica with 118 species (9 families), followed by Rodentia (51 species, 8 families), Artiodactyla (31 species, 7 families) and Carnivora (25 species, 6 families; Figure 2). About 88 % of the species are primarily terrestrial environments and 12 % are fully adapted to an aquatic life. In terms of evolutionary distinctiveness (i. e., a measurement of the uniqueness of a species evolutionary history), the updated list includes two artiodactyls Physeter macrocephalus and Balaenoptera musculus, the perissodactyl Tapirus bairdii, and the sirenian Trichechus manatus (^{May-Collado and Agnarsson 2011}; ^{Isaac et al. 2007}).

Figure 1 Changes in the number of mammal species from previous species lists for Costa Rica ranging from 1869 to date; orders taxonomic classification follows this work. References: ^{Frantzius (1869}), ^{Alfaro (1897}), ^{Goodwin (1946}), ^{Wilson (1983}), ^{Rodríguez and Chinchilla (1996}), ^{Rodríguez-Herrera et al. (2002}), Rodríguez-Herrera et al. (2014a). 

Endemism. Within the list, we listed 30 mammal species that are endemics to some specific region within the geographic area ranging from southern Nicaragua to western Panama, as follows. A total of 20 species have a distribution that encompasses Costa Rica and Panama. These species include members of the orders Didelphimorphia (1 species), Lagomorpha (1), Rodentia (13), Primates (1), Eulipotyphla (2), and Chiroptera (2). The Nicaraguan woolly mouse opossum Marmosa nicaraguae, and two species of rodents Reithrodontomys brevirostris and R. paradoxus are distributed in northern Costa Rica and are shared only with Nicaragua. Seven species are exclusively found in Costa Rica, six rodents Heterogeomys heterodus, Heteromys nubicolens, H. oresterus, Reithrodontomys cherrii, R. musseri, R. rodriguezi, and one shrew Cryptotis monteverdensis. Among these species, the taxonomic group with the greatest endemism corresponds to the order Rodentia, with 21 species, followed by Eulipotyphla with three, and Chiroptera with two (Supplementary material).

Conservation status. According to the IUCN (^{IUCN 2022}), eight species are reported as Endangered. These include the manatee Trichechus manatus, the tapir Tapirus bairdii, the primates Aloautta palliata and Saimiri oerstedii, the pinnipeds Arctocephalus galapagoensis and Zalophus wollebaeki, and the artiodactyls Balaenoptera borealis, and B. musculus. Six species are considered Vulnerable, including the giant anteater Myrmecophaga tridactyla, the primates Ateles geoffroyi and Cebus imitator, the oncilla Leopardus tigrinus, the white-lipped peccary Tayassu pecari, and the endemic lagomorph species Sylvilagus dicei; nine species are listed as Near Threatened, and 11 as Data Deficient, with six endemics among them. Nationally, according to environmental authorities (^{SINAC 2017}), 21 Costa Rican mammal species are endangered with extinction (Supplementary material). These include all six species of felids, three out of four monkey species, and the endemic rodents Reithrodontomys musseri and Rheomys raptor. In addition, a total of 42 species, including nine endemics, have seen their populations reduced or threatened (Supplementary material).

Figure 2 Distribution of the number of mammal species and families according to orders in Costa Rica. 

Changes in distribution. In terms of the distribution of localities of the recently recorded species Cryptotis monteverdensis, Ichthyomys tweedii, Cynomops greenhalli, Diplomys labilis, Micronycteris tresamici, Molossus alvarezi, Mormoops megalophylla, Myotis armiensis, Nyctinomops laticaudatus, and Speothos venaticus there is no clear pattern. Most of the new species are the result of taxonomic changes, although some indicate range expansion towards both borders of the country, with most of the new ones occurring in lowlands (Figure 3).

Taxonomic changes. Several taxonomic changes have occurred in the last decade at various taxonomic levels. These changes include:

Orders

Eulipotyphla. Based on phylogenetic analysis using molecular data (^{Douady et al. 2002}), and following the classification proposed by ^{Wilson and Mittermeier (2018}), we acknowledge the inclusion of the former orders Soricomorpha (shrews) and Erinaceomorpha (hedgehogs) in the widely accepted order Eulipotyphla.

Artiodactyla. Following the International Code of Zoological Nomenclature (^{Asher and Helgen 2010}), and according to the most recent morphological and molecular phylogenetic analyses (e. g., ^{Agnarsson and May-Collado 2008}; ^{Hassanin et al. 2012}; ^{Gatesy et al. 2013}, ²⁰¹⁷), we recognized Cetacea as an infraorder of the order Artiodactyla, along with their respective parvorders and families.

Families

Chlamyphoridae. Molecular phylogenetic analysis including fossils and extant species supports the division of the traditional family Dasypodidae into the families Chlamyphoridae and Dasypodidae (^{Delsuc et al. 2016}; ^{Gibb et al. 2016}). Dasypodidae is currently restricted to the genus Dasypus, while all other modern armadillos, including Cabassous, and the extinct glyptodonts are grouped in Chlamyphoridae.

Choloepodidae. Two-toed sloths of the genus Choloepus are now placed in a new family, Choloepodidae, instead of the family Megalonychidae. This new placement is based on phylogenetic analysis of DNA data from fossils and extant species (^{Delsuc et al. 2019}; ^{Presslee et al. 2019}).

Figure 3 Map showing localities of recorded new mammal species for Costa Rica since ^{Rodríguez-Herrera et al. (2014}) list: 1, Micronycteris tresamici; 2, Mormoops megalophylla; 3, Cryptotis monteverdensis; 4, Molossus alvarezi; 5, Nyctinomops laticaudatus; 6, Cynomops greenhalli; 7, Myotis armiensis; 8, Speothos venaticus; 9, Ichthyomys tweedii; 10, Diplomys labilis. 

Subfamilies

Former Phyllostominae. We follow the proposal of ^{Baker et al. (2016}), and ^{Cirranelo et al. (2016)}, who recognized 11 subfamilies and 12 tribes within the family Phyllostomidae, adding the following subfamilies to the list: Glyphonycterinae, Lonchophyllinae, Lonchorhininae, and Micronycterinae.

Genera

Heterogeomys. Following the latest systematic revision of the genus Orthogeomys (^{Spradling et al. 2016}), we recognize the genus Heterogeomys for the different species of the family Geomyidae occurring in Costa Rica. The genus Orthogeomys is restricted to the species O. grandis, distributed from México to Honduras.

Heteromys. Phylogenetic analysis based on molecular data of the family Heteromyidae shown that the genus Liomys is paraphyletic with respect to Heteromys (^{Hafner et al. 2007}). Therefore, the formal taxonomy of the group suggests a synonymy between the two genera, and the name Heteromys salvini is accepted.

Coendou. According to the latest research in systematics and phylogeny of the family Erethizontidae (^{Voss 2011}; ^{Voss et al. 2013}; ^{Menezes et al. 2021}), the correct and most commonly used genus is Coendou and not Sphiggurus, for Coendou mexicanus.

Gardnerycteris. According to phylogenetic analysis, the new genus Gardnerycteris is recognized for the former members of Mimon under the taxon "Anthorhina'' (represented by M. crenulatum and M. koepckeae; ^{Hurtado and Pacheco 2014}). Thus, Gardnerycteris crenulatum is accepted as a valid species.

Artibeus. In accordance with the most recent morphological and molecular phylogenetic analysis (^{Baker et al. 2016}; ^{Cirranelo et al. 2016}; ^{Cirranelo and Simmons 2020}), the genus Artibeus is used for the forms formerly assigned to the genus Dermanura.

Dasypterus. We follow the proposal of ^{Baird et al. (2015}, ²⁰²¹) of three separate genera within the tribe Lasiurini: Lasiurus (red bats), Dasypterus (yellow bats), and Aeorestes (hoary bats). Thus, we recognize de genus Dasypterus for the yellow bats L. ega and L. intermedius.

Herpailurus. The species Puma yagouaroundi was reassigned to the genus Herpailurus according to morphometric analyses by ^{Segura et al. (2013}). Although some authors still use the genus Puma for the species (e. g., ^{Li et al. 2016}; ^{Tamazian et al. 2021}), we follow the designation from the Cat Classification Task Force of the IUCN Cat Specialist Group (^{Kitchener et al. 2017}).

Neogale. According to the latest review of the phylogeny and nomenclature of the genus Mustela, M. frenata should now be recognized in the genus Neogale (^{Patterson et al. 2021}).

Dicotyles. In accordance with the International Code of Zoological Nomenclature the genus Dicotyles is accepted as valid, and the former genus Pecari becomes a junior synonym of it (^{Acosta et al. 2020}).

Species

Marmosa nicaraguae. According to the latest phylogenetic revision using molecular data of the didelphid marsupial genus Marmosa, M. nicaraguae was separated and recognized as a valid species from M. alstoni (^{Voss et al. 2021}). Therefore, both species deserve an endemic status, M. nicaraguae with a distribution limited to Nicaragua and Costa Rica, and M. alstoni distributed in Costa Rica and Panama (^{Voss et al. 2021}; ^{Carter 2022}).

Philander melanurus. This species was splitted from the Philander opossum species complex and validated as a species after phylogenetic and morphological analysis (^{Voss et al. 2018}).

Cyclopes dorsalis. Based on phylogenetic analyses using molecular data, coalescent analyses of species delimitation, cranial diagnostic characters, and patterns of coloration and fur structure, we accept the proposal of ^{Miranda et al. (2018}) to separate the species Cyclopes didactylus into seven equally valid species. Therefore, the species recognized for Costa Rica, with a Mesoamerican distribution, corresponds to C. dorsalis, while C. didactylus is restricted to the northeastern region of South America.

Cryptotis orophilus. Following the ^{International Commission on Zoological Nomenclature (2006)} the specific epithet changes from orophila to orophilus because Cryptotis gender is masculine.

Peromyscus nicaraguae. This species was separated from the P. mexicanus species complex and revalidated as a species by ^{Pérez Consuegra and Vázquez-Domínguez (2015}). The distribution reported by the authors includes only Honduras and Nicaragua, however two subspecies of P. nudipes, hesperus and orientalis, are included as synonyms of P. nicaraguae (^{Bradley et al. 2016}), which have been reported in the past for the northern and central mountain ranges of Costa Rica respectively, confirming its presence in the country.

Peromyscus nudipes. Mitochondrial cytochrome-b gene data revealed that the Peromyscus mexicanus species complex has a polyphyletic origin (^{Pérez Consuegra and Vázquez-Domínguez 2015}). Therefore, it was decided to elevate P. nudipes to specific level, due to its monophyletic origin (^{Bradley et al. 2016}). This species has a restricted distribution to the highlands of the Talamanca Mountain Range in Costa Rica and Panama.

Reithrodontomys cherrii. According to molecular (^{Arellano et al. 2005}), and morphological data (^{Gardner and Carleton 2009}), R. cherrii was separated from R. mexicanus and is recognized as a valid species. Recently, this condition was also reinforced with ecological data (^{Martínez-Borrego et al. 2022}). R. cherri is an endemic species and its distribution is restricted to the highlands of central Costa Rica.

Reithrodontomys garichensis. This species was recognized as such and separated from the R. mexicanus species complex based on morphological data (^{Gardner and Carleton 2009}). R. garichensis is distributed in the Talamanca Mountain Range in Costa Rica and Panama.

Melanomys chrysomelas. Using mitochondrial DNA nucleotide sequences of the cytochrome-b gene, phylogenetic relationships were inferred in Melanomys caliginosus (^{Hanson and Bradley 2008}). This study included samples from populations in Nicaragua, Costa Rica, Panama, Venezuela and Ecuador, resulting in the elevation of these four groups to a specific level. Thus, the accepted species for Costa Rica is M. chrysomelas, and is distributed in Honduras, Nicaragua and Costa Rica (^{Hanson and Bradley 2008}; ^{Wilson et al. 2017}).

Oligoryzomys costaricensis. This species was separated from the Oligoryzomys fulvescens species complex according to Bayesian analyses of the mitochondrial cytochrome-b gene (^{Hanson et al. 2011}). According to this study the form of this species complex accepted for Nicaragua, Costa Rica and Panama is O. costaricensis.

Gardnerycteris keenani. Based on genetic analyses and morphological comparisons, it was proposed to elevate the subspecies Gardnerycteris crenulatum keenani to specific level (^{Hurtado and D'Elía 2018}).

Diaemus youngii. The correct original spelling of the species epithet is youngii and not youngi (^{Kwon and Gardner 2008}).

Lophostoma silvicola. The specific epithet changes from silvicolum to silvicola because it is an invariable noun ^{(MDD 2022}).

Tonatia bakeri. Based on descriptions and morphometric analyses, and a phylogenetic reconstruction, the three recognized subspecies of T. saurophila were recognized and elevated to species level (^{Basantes et al. 2020}). Tonatia bakeri is distributed from southeastern México to northern South America (^{Wilson and Mittermeier 2019}).

Glossophaga mutica. Based on morphometric analyses with cranial characteristics and their relationship with environmental variables, the four subspecies of Glossophaga soricina were elevated to specific level (^{Calahorra-Oliart et al. 2021}). The distribution of G. mutica includes Central America.

Artibeus aztecus and A. toltecus. It is appropriate to use the specific epithets aztecus and toltecus instead of azteca and tolteca because Artibeus gender is masculine.

Chiroderma gorgasi. According to the latest phylogenetic revision of the genus Chiroderma (^{Lim et al. 2020}), based on morphological and molecular analyses, the trans-Andean populations of C. trinitatum should be elevated to specific level, adopting the name C. gorgasi.

Uroderma convexum. The trans-Andean subspecies of U. bilobatum was elevated to specific level according to a review of the genus Uroderma, through analyses of morphological, karyotypic, and molecular variation, and taxonomic affinities between geographic variants (^{Mantilla-Meluk 2014}).

Eumops ferox. Based on morphological and genetic analyses, the Eumops glaucinus species complex was separated into four entities (^{McDonough et al. 2008}). The species E. ferox was defined for the Caribbean region, México and Central America, while E. glaucinus has a South American distribution.

Molossus nigricans. Based on the most recent phylogenetic analysis of the genus Molossus (^{Loureiro et al. 2020}), M. nigricans is revalidated and recognized as a distinct species from M. rufus. The former has a Mesoamerican distribution, and the latter is restricted to South America.

Lasiurus frantzii. According to a molecular systematic review of the tribe Lasiurini, L. frantzii was recognized as a distinct species from L. blossevillii, leaving the former with a Mesoamerican distribution (^{Baird et al. 2015}), including Costa Rica.

Myotis pilosatibialis. The subspecies Myotis keasy pilosatibialis was elevated to specific level and separated from M. keaysi according to morphological and phylogenetic studies (^{Mantilla-Meluk and Muñoz-Garay 2014}; ^{Carrion-Bonilla and Cook 2020}); this being the species present in Costa Rica.

Kogia sima. The specific epithet changes from simus to sima (^{McGowen et al. 2020}).

Recent records since^{Rodríguez-Herrera et al. (2014}) list

Cryptotis monteverdensis. We add a new species of shrew, belonging to the Cryptotis thomasi group, described for the Monteverde Cloud Forest Biological Reserve, Puntarenas Province (^{Woodman and Timm 2017}).

Ichthyomys tweedii. This species was recorded for southern Costa Rica, at the Las Cruces Biological Station (^{Ramírez-Fernández et al. 2020}). This record represents the northern distribution limit for the genus Ichthyomys.

Diplomys labilis. Reported for the Osa Peninsula, Puntarenas Province, in the south of the country (^{Ramírez-Fernández et al. 2015}).

Mormoops megalophylla. Captured at the Venado Caves, Alajuela Province (Vicente and Ledezma comm. pers.; see ^{York et al. 2019}).

Micronycteris tresamici. A new species described based on morphometric analysis, and cariological and morphological comparisons (^{Siles and Baker 2020}). Confirmed for Alajuela and Guanacaste provinces in Costa Rica, and Honduras.

Molossus alvarezi. Described by ^{González-Ruiz et al. (2011}), apparently this species used to be misidentified as Molossus sinaloae, from which it differs in size, fur coloration, and other morphological characteristics. M. sinaloae distribution is restricted to México, therefore we replaced it with the new species M. alvarezi.

Cynomops greenhalli. Reported for Veragua Rainforest, Liverpool, ^{Limón Province, and confirmed in scientific collections by Salas-Solano et al. (2020}). This represents a distribution range extension into the Caribbean for the species in Central America.

Nyctinomops laticaudatus. Reported for Santa Ana, San José Province (^{Villalobos-Chaves et al. 2018}).

Myotis armiensis. This species was described by ^{Carrion-Bonilla and Cook (2020}). Its distribution includes the premontane and montane forests of Chiriquí (Panama), Valle del Silencio (Costa Rica), and the Cordillera Oriental (Ecuador).

Speothos venaticus. Reported for Zona Protectora Las Tablas, Talamanca Mountain Range (^{González-Maya et al. 2017}).

Discussion

Increasing interest in studying mammals, not only abroad, but also locally in Costa Rica (^{Rodríguez-Herrera et al. 2005}, 2014b) is leading to the discovery of new species. Ongoing systematic and phylogenetic revisions using a combination of fossils, morphology, and molecular data is revealing cryptic species, and more powerful hypotheses about the evolutionary relationships of mammals at various taxonomic levels. This is particularly evident in the orders Chiroptera, Rodentia and Eulipotyphla which are not only small-sized mammals from very diverse groups, but also more taxonomically challenging (e. g., cryptic species, species complexes) than other orders of mammals. This is reflected in the new additions to the list, where six bat species, two rodent species, and one shrew are among the ten recent records. Of these, four correspond to new species descriptions to science: the bats M. tresamici, M. alvarezi, and M. armiensis; and the shrew C. monteverdensis. The latter stands out for being an endemic species for Costa Rica, known only for the Monteverde region, Puntarenas Province (^{Woodman and Timm 2017}).

Another species that stands out among the new records, belonging to the well-studied group of the carnivores, is the bush dog Speothos venaticus. This poorly known species, reported to be rare throughout its distribution, was recorded in camera traps for southern Costa Rica (^{González-Maya et al. 2017}). According to the authors, the low frequency of records of this species in the study area is consistent with and reinforces the idea of its cryptic habits and natural rarity. This also highlights the great importance and scope of modern technologies for field work, such as camera traps, and long-term research, in developing complete mammal inventories, making it possible to record species that would otherwise go unnoticed.

Regarding aquatic species, as expected the cetaceans are the most diverse group of marine mammals within the Costa Rican Exclusive Economic Zone with 27 species. However, it is important to highlight that this is likely an underestimation. While monitoring efforts in terrestrial habitats continue to grow in Costa Rica, the aquatic environments remain largely unexplored. Deep diving and offshore species are likely missed in opportunistic boat surveys. To this day, no dedicated effort to evaluate the species richness and abundance of cetaceans in Costa Rican waters have taken place. Most survey efforts are near the coast, and temporally and spatially limited (^{May-Collado et al. 2018}).

Regarding the last list of mammals published for the country (^{Rodríguez-Herrera et al. 2014}a), two bat species, Sturnira hondurensis and M. sinaloae, and four cetaceans, Kogia breviceps, Mesoplodon europaeus, M. ginkgodens and Stenella clymene, were removed from our list. The bats were previously included, most likely given they are cryptic species with respect to S. burtonlimi and M. alvarezi, respectively, and having little knowledge about their taxonomy, their correct identification has been mistaken since the first records. In the case of cetaceans, these were included in the list based on distribution maps from various sources, that generalize their presence throughout the Pacific or Indian Ocean (e. g., ^{MacLeod et al. 2006}; ^{Jefferson and Braulik 2018}; ^{Kiszka and Braulik 2020}). However, these species have not yet been documented in the field or in strandings in Costa Rican territory.

The main areas of mammal endemism in Costa Rica correspond to the high parts of the different mountain ranges, with 21 of the 30 endemic species restricted to these regions, mainly in the mountainous extension of the Talamanca Mountain Range in Costa Rica and Panama. This mountain range presents the highest elevations in the country, reaching a maximum of 3820 masl (^{Kappelle and Horn 2005}), is considered one of the five great forests of Mesoamerica, and is home to the largest forest extension in the country, with more than 400,000 ha of protected areas. These high elevation regions are considered endemism hotspots because of its historical biogeographical formation that has served as a refugee for some species, due to the isolation of relatively small areas with specific climate ranges enhancing speciation rates (^{Obando 2002}; ^{Savage 2002}; ^{Kluge and Kessler 2006}). It is important to highlight rodents among the endemic species in the country, which comprises 70 % of the total, being at the same time one of the least known groups and with most uncertain conservation status.

Among the Mesoamerican countries, Costa Rica has historically stood out as a leader in conservation. Costa Rica has 166 protected areas that cover approximately 25 % of the national territory (^{Alvarado et al. 2012}; ^{González-Maya et al. 2015}). These protected areas include 50 % of the coastline and 20 of them are exclusive marine protected areas (^{Alvarado et al. 2012}). In addition, the land administration has favored the prevalence of wildlife populations in much of the country, including species categorized as threatened and with a special conservation status, both nationally and globally (^{SINAC 2017}; ^{IUCN 2022}). In groups such as primates and felids, all species are under some category of threat, and the same happens with the tapir T. bairdii, the largest land mammal in the region. In the case of the giant anteater, listed by both ^{SINAC (2017)} and ^{IUCN (2022)}, this has been considered as extirpated from Costa Rica by some authors (^{Ruiz León 2019}).

For other members of the Costa Rican mammal assemblage, long-term monitoring efforts are urgently needed to help identify the impact of direct and indirect anthropogenic activities on their populations. In particular for endemic species, most of which are not included under any threat category despite poor knowledge on its biology and its reduced global distribution range, so its conservation status should be carefully reviewed. Management of protected areas in Costa Rica over time has provided space for the mammal diversity recorded in this study; however, it is necessary to invest in conservation efforts, especially on species that receive less attention, to guarantee their survival and presence in Costa Rican territory in the future.

Although some researchers consider Costa Rican mammalian diversity well known, still new species are continuously being described and some are even periodically reported for the first time for the country. This is reinforced not only by cientific research, but it encompasses constant informal field work, observation and documentation of wildlife by local naturalists; furthermore, growing citizen science and participatory research initiatives (e. g., camera-trapping monitoring, bird counts) are now surveying many areas across the country and will provide new information about multiples groups in the coming years (^{Gómez Hoyos et al. 2021}). Moreover, contributions on systematics have proved their need and value as taxonomic boundaries between species from complex groups, as bats and rodents, are being clarified adding more changes to the list.

Although multiple threats still exert pressure over many mammal populations in the country (^{González-Maya et al. 2015}, ²⁰¹⁶), Costa Rica stood globaly as a leader in conservation, and the country’s economy benefits largely from ecotourism (^{Echeverri et al. 2022}). This is reflected in the recent creation of new protected areas (^{Presidencia de la República de Costa Rica 2022}), where more than 15,000,000 hectares were added. So we expect that the country will continue towards a conservation-minded path for the future, maintaining committed efforts for safeguarding its biodiversity for the long term, although still many challenges remain to be covered by local government and policies.