Hibernacula of bats in Mexico, the southernmost records of hibernation in North America.

Although Mexico holds the southernmost hibernating bats in North America, information on winter behavior and hibernacula microclimate use of temperate Mexican bats is limited. We studied hibernating bats at high altitudes (>1,000 m a.s.l.) in northern and central Mexico during 5 consecutive winters. Our aims were to document and describe the hibernacula, winter behavior (such as abundance and roost pattern), and microclimates (estimated as adjacent substrate temperature) of cave-hibernating bats in Mexico. We found 78 hibernacula and 6,089 torpid bats of 10 vespertilionid species, increasing by over 50% the number of cave-hibernating bat species and quadrupling the number of hibernacula for Mexico. Hibernacula were at altitudes between 1,049 and 3,633 m a.s.l., located in 3 mountain ranges, mainly in oak and conifer forests. Myotis velifer was the most common species, followed by Corynorhinus townsendii and C. mexicanus. We recorded the adjacent substrate temperatures from 9 species totaling 1,106 torpid bats and found differences in microclimate use among the 3 most common species. In general, abundance of torpid bats in our region of study was similar to those in the western United States, with aggregations of tens to a few hundred individuals per cave, and was lower than in the eastern United States where a cave may hold thousands of individuals. Knowledge of bat hibernation is crucial for developing conservation and management strategies on current conditions while accommodating environmental changes and other threats such as emerging diseases.

Aunque México tiene los murciélagos hibernantes más sureños en Norteamérica, la información sobre el comportamiento invernal y el uso de microclimas en los refugios de hibernación de los murciélagos templados mexicanos es limitada. Estudiamos a los murciélagos hibernantes en altitudes altas (>1000 msnm) en el norte y centro de México durante cinco inviernos consecutivos. Nuestros objetivos fueron documentar y describir las cuevas de hibernación, el comportamiento invernal (como la abundancia y patrón de percha), y el uso de microclimas (estimado como la temperatura del sustrato adyacente), de los murciélagos que hibernan en cuevas en México. Encontramos 78 cuevas de hibernación con 6089 murciélagos en torpor de 10 especies de vespertiliónidos, incrementando en más del 50% el número de especies de murciélagos que hibernan en cuevas y cuadriplicando el número de cuevas de hibernación para México. Las cuevas de hibernación estuvieron en elevaciones entre 1049 y 3633 msnm, localizadas en tres cadenas montañosas, principalmente en bosques de encinos y coníferas. Myotis velifer fue la especie más común, seguida por Corynorhinus townsendii y C. mexicanus. Reportamos las temperaturas del sustrato adyacente de 1106 murciélagos en torpor de nueve especies y encontramos diferencias en el uso de microclimas entre las tres especies más comunes. Aquí proveemos información relevante para especies de murciélagos templados en la ocurrencia más sureña de hibernación de murciélagos en Norteamérica. En general, la abundancia de murciélagos en torpor que encontramos fue similar a las del oeste de Estados Unidos, con agregaciones de decenas y algunos cientos de individuos por cueva; y fue menor que las del este de Estados Unidos, donde las cuevas pueden albergar miles de murciélagos. El conocimiento de la hibernación de murciélagos es crucial para el desarrollo de estrategias de conservación y manejo adecuadas en la actualidad y mientras se adaptan a los cambios ambientales y a otras amenazas tales como las enfermedades emergentes.

Did Azara discover Myotis simus or Myotis midastacus (Mammalia: Chiroptera: Vespertilionidae) at least a century before their formal description?

The true identity of the "Chauve-Souris Onzieme ou Chauve-Souris Cannelle" of Azara (1801) and the "LXXXII Murcielago Acanelado" of Azara (1802) has never been clarified. Though it has historically been associated with the Red Myotis, Myotis ruber (É. Geoffroy St.-Hilaire, 1806), there are clear inconsistencies with that species. Unusual features of the description such as the position of the attachment of the wing membrane to the limbs confirm that the species described by Azara belongs to the Myotis simus Thomas, 1901 group. Two members of that group occur in Paraguay, from where Azara described his specimen: Myotis cf. simus and the recently described Myotis midastacus Moratelli & Wilson, 2014. Measurements and collection locality slightly favour its identity as the former, but it is not possible to conclusively state which of these species Azara had in his possession.(AU)

The natural interaction between Myotis nigricans (Schinz, 1821) and its trematodes: A histopathological analysis.

Bats have a wide diversity of digeneans; however, even with the recent increased interest in studies of parasites on these hosts, there are no data on the microscopic alterations of this host-parasite interaction. The present work characterizes and compares the histological aspects of the liver, gallbladder, and intestine of non-parasitized and parasitized Myotis nigricans by digeneans. Ten specimens of Myotis nigricans collected in an urban area of Western Amazonia were analyzed for parasites. The digeneans were removed from the hosts and identified. Tissue samples of the liver, gallbladder, and intestines of parasitized and non-parasitized hosts were collected for histological studies. The gallbladder was observed in repletion and presents mucosa formed by simple epithelium that varies from cubic to cylindrical. The hepatic lobes do not have a classic polyhedral-hexagonal aspect. Variations in basophilia, acidophile, and cytoplasmatic granulations were observed in hepatocytes. The parasitism of the intestinal digeneans was restricted to space delimited by the extensions of villi in high association with the intestinal epithelium, not invading the region of the intestinal glands at the base of the villi. Trematodes maintained attached to the villus by the oral sucker and acetabulum, connected by a "pleat" composed of epithelium and lamina propria layers. We observed no signs of inflammatory processes and cellular defense infiltrates in host tissues. Cytochemistry alterations, size variation, and granular deposits in hepatocytes, enterocytes, and goblet cells were observed. Thus, this report is the first study of the natural parasite-host interaction in the liver, gallbladder, and intestine in M. nigricans in the neotropical region.

Redescription of Myotis atacamensis (Chiroptera: Vespertilionidae) with neotype designation

Myotis atacamensis (Lataste, 1892) was described based on three syntypes from San Pedro de Atacama, Chile. The type series is lost. The original description was based on few external and cranial characters, and the diagnosis became obsolete and useless considering the current diversity of South American Myotis. Based on 12 specimens of M. atacamensis from southern Peru and northern Chile, we provide a morphological comparison with its South American congeners, designate a neotype, and provide a new diagnosis.(AU)

A New Species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from Myotis riparius Handley, 1960 (Chiroptera: Vespertilionidae) in the Atlantic Forest of Brazil, with a Checklist of Eimeria spp. Reported from Bats.

INTRODUCTION: A new coccidian species of the genus Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae), is reported from the bat host Myotis riparius Handley from Ilha Grande, a large island off the coast of the State of Rio de Janeiro, in southeastern Brazil. METHODS: Bats were captured in 13 mist nets (10 × 3 m), which were set within the experimental plots, and through active searches of the daytime roosts of Molossus molossus Pallas found in Vila Dois Rios. Containment was made in bags for the collection of feces and identification of coccidia. A survey was conducted on the coccidia species described so far (Table 2). RESULTS: The oöcysts of Eimeria riparii n. sp. are ellipsoidal to cylindroidal with an extremely thin, bi-layered wall, slightly rough. Two polar granules are present, micropyle and oöcyst residuum are both absent. The sporocysts are ellipsoidal, the sporocyst residuum is formed by sparse, rounded granules of varying sizes; the Stieda body is trapezoidal and a sub-Stieda body is absent. Sporozoites are banana shaped. With the new species described here, a total of 40 Eimeria spp. have been described infecting bat hosts, belonging to 30 species of 18 genera and 5 families. CONCLUSION: The subsequent increase in the known diversity of bats has been derived from the ongoing expansion of research in a number of different areas of taxonomy and ecology although the number of studies of the associated coccidian parasites of the family Eimeriidae has increased more slowly.

Bite force, cranial morphometrics and size in the fishing bat Myotis vivesi (Chiroptera: Vespertilionidae)

Abstract Fish-eating in bats evolved independently in Myotis vivesi (Vespertillionidae) and Noctilio leporinus (Noctilionidae). We compared cranial morphological characters and bite force between these species to test the existence of evolutionary parallelism in piscivory. We collected cranial distances of M. vivesi, two related insectivorous bats (M. velifer and M. keaysi), two facultatively piscivorous bats (M. daubentonii and M. capaccinii), and N. leporinus. We analyzed morphometric data applying multivariate methods to test for differences among the six species. We also measured bite force in M. vivesi and evaluated if this value was well predicted by its cranial size. Both piscivorous species were morphologically different from the facultatively piscivorous and insectivorous species, and skull size had a significant contribution to this difference. However, we did not find morphological and functional similarities that could be interpreted as parallelisms between M. vivesi and N. leporinus. These two piscivorous species differed significantly in cranial measurements and in bite force. Bite force measured for M. vivesi was well predicted by skull size. Piscivory in M. vivesi might be associated to the existence of a vertically displaced temporal muscle and an increase in gape angle that allows a moderate bite force to process food.(AU)

Resumen La alimentación por peces en murciélagos evolucionó independientemente en Myotis vivesi (Vespertilionidae) y Noctilio leporinus (Phyllostomidae). En este estudio se compararon características craneales morfológicas y fuerza de mordida entre estas especies, para probar la existencia de paralelismo evolucionario en piscivoría. Se recolectaron distancias craneales en M. vivesi, dos parientes insectívoros (M. velifer y M. keaysi), dos murciélagos piscívoros facultativos (M. daubentonii y M. capaccinii), y N. leporinus. Se analizaron datos morfométricos aplicando múltiples métodos para probar las diferencias entre las seis especies. Se midió la fuerza de mordida en M. vivesi y se evalúo si puede ser predicha por el tamaño del cráneo. Las especies piscívoras fueron morfológicamente diferentes de las facultativamente piscívoras y las insectívoras, el tamaño del cráneo tuvo una contribución significativa en esta diferencia. Sin embargo, no encontramos semejanzas morfológicas y funcionales que puedan ser interpretadas como paralelismos entre M. vivesi y N. leporinus. Estas dos especies piscívoras difieren significativamente en medidas craneales y fuerza de mordida. La fuerza de mordida en M. vivesi fue efectivamente predicha por el tamaño de cráneo. La piscivoría en M. vivesi puede estar asociada con la existencia de un músculo temporal verticalmente desplazado y el incremento en el ángulo de apertura mandibular que permite moderar la fuerza de mordida para procesar el alimento.(AU)

The taxonomic status of Myotis aelleni Baud, 1979 (Chiroptera, Vespertilionidae).

Myotis aelleni Baud, 1979 was described based on a large series from Chubut, Argentina, and is known only from the type locality and Río Negro, also in Argentina. According to the original description, M. aelleni is closest morphologically to M. chiloensis (Waterhouse, 1840), but can be distinguished based on the tricolored dorsal hairs and skull size and shape. The taxonomic status of M. aelleni has been questioned but the species is still treated as valid. Based on qualitative and quantitative analyses of the type series of M. aelleni, and series of M. chiloensis, including the neotype, we recognize M. aelleni as a junior synonym of M. chiloensis. M. aelleni and M. chiloensis have bicolor dorsal hairs and cannot be distinguished on the basis of the skull size and shape. After synonymy, M. chiloensis occur from Central Chile and western Argentina to central Patagonia and Tierra del Fuego archipelago. Twenty-one species of Myotis occur in South America, including Trinidad and Tobago.

A comparative study of Trypanosoma cruzi infection in sylvatic mammals from a protected and a disturbed area in the Argentine Chaco.

Understanding the complex epidemiology of Trypanosoma cruzi transmission cycles requires comparative studies in widely different environments. We assessed the occurrence of T. cruzi infection in sylvatic mammals, their infectiousness to the vector, and parasite genotypes in a protected area of the Argentine Chaco, and compared them with information obtained similarly in a nearby disturbed area. A total of 278 mammals from >23 species in the protected area were diagnosed for T. cruzi infection using xenodiagnosis, kDNA-PCR and nuclear satellite DNA-PCR (SAT) from blood samples. The relative abundance and species composition differed substantially between areas. Didelphis albiventris opossums were less abundant in the protected area; had a significantly lower body mass index, and a stage structure biased toward earlier stages. The capture of armadillos was lower in the protected area. The composite prevalence of T. cruzi infection across host species was significantly lower in the protected area (11.1%) than in the disturbed area (22.1%), and heterogeneous across species groups. The prevalence of infection in D. albiventris and Thylamys pusilla opossums was significantly lower in the protected area (nil for D. albiventris), whereas infection in sigmodontine rodents was three times higher in the protected area (17.5 versus 5.7%). Parasite isolates from the two xenodiagnosis-positive mammals (1 Dasypus novemcinctus and 1 Conepatus chinga) were typed as TcIII; both specimens were highly infectious to Triatoma infestans. Fat-tailed opossums, bats and rodents were kDNA-PCR-positive and xenodiagnosis-negative. Desmodus rotundus and Myotis bats were found infected with T. cruzi for the first time in the Gran Chaco.

First evidence of frugivory in Myotis (Chiroptera, Vespertilionidae, Myotinae).

BACKGROUND: Myotis occurs from tropical to temperate regions throughout the globe, and it is the largest bat genus with more than 100 species. Most species are insect-eaters, but a few also feed on other invertebrates and fishes; there is no confirmed evidence of a plant item in their diet. NEW INFORMATION: During fieldwork in the Brazilian Atlantic Forest, small seeds were retrieved from the feces of one adult female of the Black Myotis, Myotis nigricans-one of the most common Neotropical bats. In a germination experiment, 40% of those seeds grew into seedlings. Our findings are the first evidence of fruit consumption for any Myotis species. We reject a possible contamination because the cotton bag was never used before for bats. This study is the first evidence of frugivory in the genus Myotis.

Range extension of Myotis midastactus​ (Chiroptera, Vespertilionidae) to Paraguay.

BACKGROUND: Myotis midastactus Moratelli and Wilson, 2014 (Vespertilionidae, Myotinae) was described from the Myotis simus Thomas, 1901 complex based on collections from the Bolivian Savannah. NEW INFORMATION: Four vouchers previously assigned to M. simus from the Alto Chaco in Paraguay (West of the Paraguay River) are reassigned here to M. midastactus. These specimens extend the geographic distribution of M. midastactus 1200 km southward, and constitute the first evidence of the species in the country. Based on other material from the Brazilian Pantanal and Cerrado, Central Paraguay and north-eastern Argentina, we also discuss the identity of simus-like populations south of the Amazon Basin. The status of these populations is still unclear, but the little evidence we have at hand indicates that these populations may represent another taxon-M. guaycuru Proença, 1943; whereas M. simus seems to be restricted to the Amazon basin. This hypothesis is still very speculative and requires further investigation. With the assignment of material from Alto Chaco to M. midastactus, seven species of Myotis are confirmed for Paraguay: M. albescens, M. lavali, M. levis, M. midastactus, M. nigricans, M. riparius, and M. ruber.

First record of Myotis albescens (Chiroptera, Vespertilionidae) in French Guiana.

BACKGROUND: Myotis albescens occurs from Mexico southward to Uruguay and Argentina. The species is known for all South American countries except French Guiana and Chile. NEW INFORMATION: Based on one specimen recently collected in French Guiana we fill part of the gap in the distribution of the species in South America. Myotis albescens occurs in the Guiana Shield with other four congeners, from which it can be distinguished by external and skull traits. As an aid to future identifications, we provide a key to this assemblage.

Update on the distribution of Myotis atacamensis (Chiroptera: Vespertilionidae): southernmost record and description of its echolocation / calls

Myotis atacamensis is a vespertilionid bat known from western Peru to northern Chile, where it is usually associated with coastal deserts. We report the first record of this species from central Chile, extending its geographical distribution ca. 160 km southward. This represents the first observation of M. atacamensis in the temperate sclerophyllous forest of central Chile, a pluviseasonal Mediterranean-climate ecosystem, suggesting it might not be restricted to arid and semiarid environments, as previously thought. We also present the first description of echolocation calls of this understudied species.

Update on the distribution of Myotis atacamensis (Chiroptera: Vespertilionidae): southernmost record and description of its echolocation / calls

Myotis atacamensis is a vespertilionid bat known from western Peru to northern Chile, where it is usually associated with coastal deserts. We report the first record of this species from central Chile, extending its geographical distribution ca. 160 km southward. This represents the first observation of M. atacamensis in the temperate sclerophyllous forest of central Chile, a pluviseasonal Mediterranean-climate ecosystem, suggesting it might not be restricted to arid and semiarid environments, as previously thought. We also present the first description of echolocation calls of this understudied species.(AU)

Genomic landscape of human, bat, and ex vivo DNA transposon integrations.

The integration and fixation preferences of DNA transposons, one of the major classes of eukaryotic transposable elements, have never been evaluated comprehensively on a genome-wide scale. Here, we present a detailed study of the distribution of DNA transposons in the human and bat genomes. We studied three groups of DNA transposons that integrated at different evolutionary times: 1) ancient (>40 My) and currently inactive human elements, 2) younger (<40 My) bat elements, and 3) ex vivo integrations of piggyBat and Sleeping Beauty elements in HeLa cells. Although the distribution of ex vivo elements reflected integration preferences, the distribution of human and (to a lesser extent) bat elements was also affected by selection. We used regression techniques (linear, negative binomial, and logistic regression models with multiple predictors) applied to 20-kb and 1-Mb windows to investigate how the genomic landscape in the vicinity of DNA transposons contributes to their integration and fixation. Our models indicate that genomic landscape explains 16-79% of variability in DNA transposon genome-wide distribution. Importantly, we not only confirmed previously identified predictors (e.g., DNA conformation and recombination hotspots) but also identified several novel predictors (e.g., signatures of double-strand breaks and telomere hexamer). Ex vivo integrations showed a bias toward actively transcribed regions. Older DNA transposons were located in genomic regions scarce in most conserved elements-likely reflecting purifying selection. Our study highlights how DNA transposons are integral to the evolution of bat and human genomes, and has implications for the development of DNA transposon assays for gene therapy and mutagenesis applications.

Three new bat species in the state of Oaxaca, Mexico

The state of Oaxaca, in southeastern Mexico,is one of the regions with the greatest species richness in the country,comparable even with that of some Central American countries. Over the courseof a study on the southeastern portion of the state of Oaxaca, we recorded thepresence of three new species for the state: two New World leaf-nosed bats (Phylloderma stenops and Micronycteris schmidtorum) and onevesper bat (Myotis albescens). Thelocalities of these registers represent the northeastern extreme of thegeographic distribution of the former two species. The three species includedin the present work bring the number of terrestrial mammalian wildlife speciesin Oaxaca to 209, and the number of bat species to 93.

Three new bat species in the state of Oaxaca, Mexico

The state of Oaxaca, in southeastern Mexico,is one of the regions with the greatest species richness in the country,comparable even with that of some Central American countries. Over the courseof a study on the southeastern portion of the state of Oaxaca, we recorded thepresence of three new species for the state: two New World leaf-nosed bats (Phylloderma stenops and Micronycteris schmidtorum) and onevesper bat (Myotis albescens). Thelocalities of these registers represent the northeastern extreme of thegeographic distribution of the former two species. The three species includedin the present work bring the number of terrestrial mammalian wildlife speciesin Oaxaca to 209, and the number of bat species to 93.(AU)

Ultrastructural characteristics of the spermatogenesis during the four phases of the annual reproductive cycle of the black myotis bat, Myotis nigricans (Chiroptera: Vespertilionidae).

Myotis nigricans is an endemic species of vespertilionid bat, from the Neotropical region, that resembles temperate zone bats in their reproductive cycle; presenting an annual reproductive cycle with two periods of testicular regression, which are not linked to the apoptotic process and seems to be not directly linked to any seasonal abiotic variation. Thus, this study aimed to ultrastructurally evaluate their reproductive cycle. The process of testicular regression could be divided into four periods: active; regressing; regressed and recrudescence; with all presenting distinct characteristics. The active period was similar to that of other bats, presenting the complete occurrence of spermatogenesis, with three main types of spermatogonia (A(d), A(p), and B) and 12 steps in spermatid differentiation; however, it differed in having the outer dense fibers 1, 5, 6, and 9 larger than the others. These three types of spermatogonia undergo considerable morphologic changes from regressing to the regressed period, and in the recrudescence, they return to the basic morphology, which reactivates spermatogenesis. In conclusion, our study described the process of spermatogenesis, the ultrastructure of the spermatozoa and the distinct morphologic variations in the ultrastructure of the testicular cells of M. nigricans during the four different periods of its annual reproductive cycle.

The taxonomic status of Myotis levis levis and Myotis levis dinellii (Mammalia: Chiroptera: Vespertilionidae)

Investigating the Myotis levis complex is important for understanding the taxonomic status of the two subspecies currently recognized in it: Myotis levis levis (I. Geoffroy, 1824) and M. levis dinellii Thomas, 1902. Both M. levis levis and M. levis dinellii have been recently observed in sympatry in Argentina. This finding suggests that these populations might in fact correspond to distinct species rather than subspecies, as they have traditionally been designated. By using a multivariate morphometric approach, we demonstrate that M. l. levis has secondary sexual dimorphism in several measurements, with females being larger than males; sexual dimorphism was not detected in M. levis dinellii. However, we found morphometric differences between the two taxa. These differences exceeded those documented for other Neotropical Myotis. Based on their sympatry, morphological, and morphometrical differences, we propose a change in the status of both subspecies to M. levis and M. dinellii.

Habitos alimeticios de un ensamble de murciélagos insectívoros aéreos de un bosque montano en las Yungas Argentinas

In spite of their fundamental ecological role in the Neotropics, little is known about the diet of many bat species. Although insectivorous species have long been considered effectives insect populations controllers, there has been no systematic study of the diet of insectivorous bats in Argentina. In this study, the diet of seven species of Vespertilionidae and Molossidae families of aerial insectivorous bats was analyzed seasonally at ensemble and species level in a montane forest. Lepidoptera and Coleoptera showed high contribution in terms of percent occurrence and percent volume of the diet at both the assemblage and species levels. Coleoptera dominated fecal sample of Eptesicus chiriquinus. No seasonaldifferences were observed at the assemblage level or for species analyzed in greater detail, Histiotus macrotus and Myotis nigricans. In spite of the limited sample size, data suggest a partitioning of food resources between species of different sizes. This partitioning is likely related to size of prey that a bat can actually catch and manipulate. The consumption of Lepidoptera and Coleoptera in proportions of more than 40% shows a tendency towards specialization of the entire ensemble in these orders.

The taxonomic status of Myotis levis levis and Myotis levis dinellii (Mammalia: Chiroptera: Vespertilionidae)

Investigating the Myotis levis complex is important for understanding the taxonomic status of the two subspecies currently recognized in it: Myotis levis levis (I. Geoffroy, 1824) and M. levis dinellii Thomas, 1902. Both M. levis levis and M. levis dinellii have been recently observed in sympatry in Argentina. This finding suggests that these populations might in fact correspond to distinct species rather than subspecies, as they have traditionally been designated. By using a multivariate morphometric approach, we demonstrate that M. l. levis has secondary sexual dimorphism in several measurements, with females being larger than males; sexual dimorphism was not detected in M. levis dinellii. However, we found morphometric differences between the two taxa. These differences exceeded those documented for other Neotropical Myotis. Based on their sympatry, morphological, and morphometrical differences, we propose a change in the status of both subspecies to M. levis and M. dinellii.