77 Mammals — 2000–2017 Robert M. Timm Richard K. LaVal Mammalogists currently recognize We are fortunate that a number of nearly 6,400 species of Recent mammals biologists have worked at Monteverde worldwide and the number of new species beginning in the 1960s and considerable being recognized has increased dramatically information and voucher material are in recent decades. It is estimated that available for study. We now know that at perhaps as many as 7,500 species might least 90 of mammals occur in the greater occur when additional studies are Monteverde area. However, one of the completed. This increase in the number of outcomes of these studies is that a number of mammal species known is a result of name changes are proposed each year. exciting new discoveries in the field, as well These better reflect relationships between as additional study of scientific specimens species; however, a bewildering array of housed in museums. Using new techniques, new names often makes it difficult to including genetic data, as well as traditional understand what is happening when authors morphological studies, scientists are refer to an animal for which more than one undertaking taxonomic revisions that scientific name exists, sometimes significantly increase our understanding of surrounded by controversy. A scientific the diversity of mammals and the name associated with a species is a relationships among species. hypothesis. Eventually, usage of these new 2 names in scientific publications will lead to comparisons should be made for each zone their acceptance (or refinement, in some and not the entire list as representative of cases). Meanwhile, it is up to researchers to Monteverde. Comparisons are best made make the sometimes difficult decisions as to with specific habitats (life zones) within the whether to use the new names in our greater Monteverde area. publications. Herein, our decisions are LaVal’s (in press) extensive use of based on the current literature, our Anabat detection systems has added a experience with these species both in the number of species of bats new to the various field and in study of museum specimens, life zones that were not detected via standard and the best information currently available mist nets. This has been especially true for to us. Many of the name changes we the emballonurid and molossid bats. provide below to the list of mammals of Life zones are generally agreed to be Monteverde appear in specialized systematic biologically defined areas in which there is revisions; to assist researchers interested in notable similarity between the flora and Monteverde mammals, we provide the new fauna throughout the zone. These are often name as well as a footnote to the older defined by the species of birds and plants name. that occur there because these are easily At present, only one species of mammal, observed and that has been especially true at a newly described small-eared shrew, is Monteverde. On mountain slopes, upper apparently endemic to Monteverde. A and lower elevational limits can help to single specimen of shrew found in the define the zones, but it is generally agreed Reserve in 1973 was described recently as now that any boundaries between two Cryptotis monteverdensis; extensive efforts adjacent zones are poorly defined and to obtain additional specimens have proven flexible over time. When climate change futile to date (Woodman and Timm 2017). leads to warmer (or cooler or drier) A species of harvest mouse of the genus conditions, these elevational limits may Reithrodontomys found in the cloud forest move up or down the mountain as organisms also represents an undescribed species (see attempt to remain within the temperature below). Additionally, intriguing and humidity limits to which they are observations suggest that one or more adapted. Thus, a bat for example originally unrecognized species of rodents might be restricted to Zone 1 in Monteverde, might found in the cloud forest (LaVal, pers. obs.). move up to Zone 2 under warming Researchers who wish to make conditions (see LaVal 2004). In our 2000 comparisons between regions, habitats, or list of distributions of mammals in the elevations should use this English version or Monteverde region, we listed southern the Spanish updated version (LaVal and cotton rats as rare in zones 1 and 2. Today, Timm 2014; Apéndice 11) of our species cotton rats are abundant in those zones in lists of Monteverde mammals because a disturbed habitats. The rain shadow on the significant number of changes have been Pacific slope, heavily disturbed grassy areas, made since 2000. These changes are due in and climate change have seemly created part to a more refined understanding of abundant habitat for this grassland species at distributions and systematic relationships of Monteverde as well as elsewhere on Costa the mammals, but also to improved ability to Rica’s Pacific slopes. At Monteverde, detect species and distributional changes due plants and birds were originally used to to climatic change. Because six life zones define the life zones, whereas most species are represented in the updated species lists, of mammals were distributed across two or 3 more life zones (see Timm and LaVal book in 2000. The first in this series, 2000a, b, c). Apéndice 10 (Timm and LaVal 2014), is a Owing to our ever-increasing knowledge Spanish translation of the original Appendix of Monteverde mammals and the long-term 10 from the Monteverde book. The second work that has been done there, interesting (LaVal and Timm 2014) is a Spanish changes in distributional and ecological updated version of that original listing of patterns are being discovered. Distributions Monteverde mammals and their distributions of mammals across the elevational zones and abundance. Herein, we update the clearly are changing. LaVal documented distributions of mammals in the six life that vampire bats moved up into the zones represented in the greater Monteverde Monteverde area in the 1990s and cotton rats region, add species newly discovered in the moved up and became abundant in the past region, and provide literature updates. In decade. LaVal noted that cotton rats first these updated versions, we provide brief started appearing in zone 2 in the early comments explaining taxonomic changes 2000s, whereas they were previously known that have occurred since the original listing only from zone 1. An intriguing example of was published in 2000 provided as footnotes a truly sympatric distribution is the to the original appendix. In the References discovery of the two species of mouse below, we include the 25 publications that opossums—Marmosa mexicana and M. have appeared based on the study of zeledoni—in LaVal’s home. The mammals at Monteverde since our 2000 observations were made years apart so the overview, as well as references that we cite two similarly appearing species may not be in preparation of these updated versions. temporally sympatric, but the dry forest Keys to the bats of Costa Rica based species (M. mexicana) and the wet forest extensively on our experience at Monteverde species (M. zeledoni) are now documented were provided in English (Timm and LaVal from a single residence in Monteverde. 1998) and Spanish (Timm et al. 1999). A Three similarly-sized species of small-eared very useful and beautifully illustrated key to shrews are known from the Reserve with the rodents of Costa Rica was provided by Cryptotis nigrescens widespread and Villalobos-Chaves et al. (2016). common throughout the area, whereas C. On a positive note, two factors favor a merriami and C. monteverdensis are known bright future for Monteverde mammals: 1) only in the reserve and are both rare. An immense area of contiguous pristine Considerable differences in the forearm habitat and regenerating forest, around bones of the three similarly-appearing 50,000 hectares, has been preserved and is shrews were documented by Woodman and relatively well-protected in the Monteverde Timm (2017), and they speculated that the area; 2) Most, although not all, Monteverde differences reflected more ambulatory above mammals have distributional and ecological ground versus more semi-fossorial foraging. ranges that cover several life zones and thus This chapter was undertaken along with are less threatened by climate change than two companion chapters (apéndices 10, 11) many birds and herps that may be restricted to update the research and findings in the to one or two life zones. field of mammalogy that have taken place since the publication of the Monteverde 4 Table 1. Mammal distributions and abundances in the Monteverde region—2017. Richard K. LaVal and Robert M. Timm Scientific Name Common Name Abundance 1 Life Zone 2 _____________________________________________________________________________________________ Didelphimorpha Marsupials Didelphidae American Opossums Caluromys derbianus Woolly Opossum uncommon 1, 2, 3 Chironectes minimus Water Opossum uncertain 1 Didelphis marsupialis Common Opossum abundant 1, 2, 3, 4, 5, 6 Marmosa mexicana Mexican Mouse Opossum uncommon 1 Marmosa zeledoni Mouse Opossum common 2, 3, 5, 6 Metachirus nudicaudatus Brown Four-eyed Opossum rare 6 Micoureus alstoni Alston’s Opossum uncommon 2, 3, 6 Philander opossum Gray Four-eyed Opossum uncommon 1, 2, 3, 5, 6 Eulipotyphla Shrews Soricidae Shrews Cryptotis merriami Merriam’s Small-eared Shrew rare 3 Cryptotis nigrescens Blackish Small-eared Shrew common 2, 3, 4, 5, 6 Cryptotis monteverdensis 3 Monteverde Small-eared Shrew rare 3 Chiroptera Bats Emballonuridae