Ivan Horáček

Increasing Incidence of Geomyces destructans Fungus in Bats from the Czech Republic and Slovakia

Background White-nose syndrome is a disease of hibernating insectivorous bats associated with the fungus Geomyces destructans. It first appeared in North America in 2006, where over a million bats died since then. In Europe, G. destructans was first identified in France in 2009. Its distribution, infection dynamics, and effects on hibernating bats in Europe are largely unknown. Methodology/Principal Findings We screened hibernacula in the Czech Republic and Slovakia for the presence of the fungus during the winter seasons of 2008/2009 and 2009/2010. In winter 2009/2010, we found infected bats in 76 out of 98 surveyed sites, in which the majority had been previously negative. A photographic record of over 6000 hibernating bats, taken since 1994, revealed bats with fungal growths since 1995; however, the incidence of such bats increased in Myotis myotis from 2% in 2007 to 14% by 2010. Microscopic, cultivation and molecular genetic evaluations confirmed the identity of the recently sampled fungus as G. destructans, and demonstrated its continuous distribution in the studied area. At the end of the hibernation season we recorded pathologic changes in the skin of the affected bats, from which the fungus was isolated. We registered no mass mortality caused by the fungus, and the recorded population decline in the last two years of the most affected species, M. myotis, is within the population trend prediction interval. Conclusions/Significance G. destructans was found to be widespread in the Czech Republic and Slovakia, with an epizootic incidence in bats during the most recent years. Further development of the situation urgently requires a detailed pan-European monitoring scheme.

Dual epithelial origin of vertebrate oral teeth

The oral cavity of vertebrates is generally thought to arise as an ectodermal invagination. Consistent with this, oral teeth are proposed to arise exclusively from ectoderm, contributing to tooth enamel epithelium, and from neural crest derived mesenchyme, contributing to dentin and pulp. Yet in many vertebrate groups, teeth are not restricted only to the oral cavity, but extend posteriorly as pharyngeal teeth that could be derived either directly from the endodermal epithelium, or from the ectodermal epithelium that reached this location through the mouth or through the pharyngeal slits. However, when the oropharyngeal membrane, which forms a sharp ecto/endodermal border, is broken, the fate of these cells is poorly known. Here, using transgenic axolotls with a combination of fate-mapping approaches, we present reliable evidence of oral teeth derived from both the ectoderm and endoderm and, moreover, demonstrate teeth with a mixed ecto/endodermal origin. Despite the enamel epithelia having a different embryonic source, oral teeth in the axolotl display striking developmental uniformities and are otherwise identical. This suggests a dominant role for the neural crest mesenchyme over epithelia in tooth initiation and, from an evolutionary point of view, that an essential factor in teeth evolution was the odontogenic capacity of neural crest cells, regardless of possible ‘outside-in’ or ‘inside-out’ influx of the epithelium.

GENERIC STATUS OF THE AMERICAN PIPISTRELLES (VESPERTILIONIDAE) WITH DESCRIPTION OF A NEW GENUS

Abstract Although traditionally placed in the genus Pipistrellus, studies since the mid-1900s have shown that the western pipistrelle (P. hesperus) and eastern pipistrelle (P. subflavus), the only 2 representatives of Pipistrellus-like bats in the Western Hemisphere, do not share a most recent common ancestry with true Pipistrellus or each other. More than 20 years ago, authors recommended taxonomic revision for the American pipistrelles by placing subflavus in a separate genus called Perimyotis, and hesperus in a another separate genus called “Parastrellus.” Recently, a comprehensive study of the molecular phylogenetics of vespertilionid bats affirmed these suggested revisions. However, the name “Parastrellus” is currently unavailable according to the International Code of Zoological Nomenclature because no formal description of the genus has been provided. In this study, we provide additional morphological and genetic data demonstrating the marked divergence among hesperus, subflavus, Pipistrellus, and other Pipistrellus-like genera, and provide a formal description of a new generic name for the nominal species P. hesperus.

Development and evolution of the vertebrate primary mouth

The vertebrate oral region represents a key interface between outer and inner environments, and its structural and functional design is among the limiting factors for survival of its owners. Both formation of the respective oral opening (primary mouth) and establishment of the food‐processing apparatus (secondary mouth) require interplay between several embryonic tissues and complex embryonic rearrangements. Although many aspects of the secondary mouth formation, including development of the jaws, teeth or taste buds, are known in considerable detail, general knowledge about primary mouth formation is regrettably low. In this paper, primary mouth formation is reviewed from a comparative point of view in order to reveal its underestimated morphogenetic diversity among, and also within, particular vertebrate clades. In general, three main developmental modes were identified. The most common is characterized by primary mouth formation via a deeply invaginated ectodermal stomodeum and subsequent rupture of the bilaminar oral membrane. However, in salamander, lungfish and also in some frog species, the mouth develops alternatively via stomodeal collar formation contributed both by the ecto‐ and endoderm. In ray‐finned fishes, on the other hand, the mouth forms via an ectoderm wedge and later horizontal detachment of the initially compressed oral epithelia with probably a mixed germ‐layer derivation. A very intriguing situation can be seen in agnathan fishes: whereas lampreys develop their primary mouth in a manner similar to the most common gnathostome pattern, hagfishes seem to undergo a unique oropharyngeal morphogenesis when compared with other vertebrates. In discussing the early formative embryonic correlates of primary mouth formation likely to be responsible for evolutionary–developmental modifications of this area, we stress an essential role of four factors: first, positioning and amount of yolk tissue; closely related to, second, endoderm formation during gastrulation, which initiates the process and constrains possible evolutionary changes within this area; third, incipient structure of the stomodeal primordium at the anterior neural plate border, where the ectoderm component of the prospective primary mouth is formed; and fourth, the prime role of Pitx genes for establishment and later morphogenesis of oral region both in vertebrates and non‐vertebrate chordates.

Molecules, morphometrics and new fossils provide an integrated view of the evolutionary history of Rhinopomatidae (Mammalia: Chiroptera)

BackgroundThe Rhinopomatidae, traditionally considered to be one of the most ancient chiropteran clades, remains one of the least known groups of Rhinolophoidea. No relevant fossil record is available for this family. Whereas there have been extensive radiations in related families Rhinolophidae and Hipposideridae, there are only a few species in the Rhinopomatidae and their phylogenetic relationship and status are not fully understood.ResultsHere we present (a) a phylogenetic analysis based on a partial cytochrome b sequence, (b) new fossils from the Upper Miocene site Elaiochoria 2 (Chalkidiki, Greece), which represents the first appearance datum of the family based on the fossil record, and (c) discussion of the phylogeographic patterns in both molecular and morphological traits. We found deep divergences in the Rhinopoma hardwickii lineage, suggesting that the allopatric populations in (i) Iran and (ii) North Africa and the Middle East should have separate species status. The latter species (R. cystops) exhibits a shallow pattern of isolation by distance (separating the Middle East and the African populations) that contrasts with the pattern of geographic variation in the morphometrical traits. A deep genetic gap was also found in Rhinopoma muscatellum (Iran vs. Yemen). We found only minute genetic distance between R. microphyllum from the Levant and India, which fails to support the sub/species distinctness of the Indian form (R. microphyllum kinneari).ConclusionThe mtDNA survey provided phylogenetic tree of the family Rhinopomatidae for the first time and revealed an unexpected diversification of the group both within R. hardwickii and R. muscatellum morphospecies. The paleobiogeographic scenario compiled in respect to molecular clock data suggests that the family originated in the region south of the Eocene Western Tethyan seaway or in India, and extended its range during the Early Miocene. The fossil record suggests a Miocene spread into the Mediterranean region, followed by a post-Miocene retreat. Morphological analysis compared with genetic data indicates considerable phenotypic plasticity in this group.

Testing hypotheses of bat baculum function with 3D models derived from microCT

The baculum (os penis) has been extensively studied as a taxon‐specific character in bats and other mammals but its mechanical function is still unclear. There is a wide consensus in the literature that the baculum is probably a sexually selected character. Using a novel approach combining postmortem manipulation and three‐dimensional (3D) imaging, we tested two functional hypotheses in the common noctule bat Nyctalus noctula, the common pipistrelle Pipistrellus pipistrellus, and Nathusius’ pipistrelle Pipistrellus nathusii: (i) whether the baculum can protect the distal urethra and urethral opening from compression during erection and copulation; and (ii) whether the baculum and corpora cavernosa form a functional unit to support both the penile shaft and the more distal glans tip. In freshly dead or frozen and thawed bats, we compared flaccid penises with artificially ‘erect’ penises that were inflated with 10% formalin. Penises were stained with alcoholic iodine and imaged with a lab‐based high‐resolution x‐ray microtomography system. Analysis of the 3D images enabled us to compare the changes in relative positions of the baculum, corpora cavernosa, urethra, and corpus spongiosum with one another between flaccid and ‘erect’ penises. Our results support both functional hypotheses, indicating that the baculum probably performs two different roles during erection. Our approach should prove valuable for comparing and testing the functions of different baculum morphologies in bats and other mammals. Moreover, we have validated an essential component of the groundwork necessary to extend this approach with finite element analysis for quantitative 3D biomechanical modeling of penis function.

Alcathoe Bat (Myotis alcathoe) in the Czech Republic: Distributional Status, Roosting and Feeding Ecology

Between 2001 and 2008, we recorded Myotis alcathoe at nine sites within three distant areas in the Czech Republic. The species identification was confirmed with cyt b sequences and four distinct haplotypes were identified. All the localities exhibit surprisingly uniform habitat characteristics: (1) old full-grown oak-hornbeam forests, with (2) numerous large trees in advanced stages of decay are present, and (3) a very small to large water bodies and/or patches of riparian vegetation surrounded by the forest. Using radiotracking techniques, we discovered 27 day roosts of M. alcathoe, located mostly in big oak, birch and lime trees inside extensive forest stands. All roosts were fissures or small cavities in a tree trunk and in branches in the canopies, some 16m above the ground. Bats preferred trees that were higher, had higher canopy and canopy basement and had larger diameter at breast height than other available trees. Roost trees were surrounded by lower trees with lower canopy basements than available trees. Roost trees were in a poorer condition than other available trees. Roosts were occupied by up to 83 individuals in July but usually single individuals were found in the roosts in September. In contrast to syntopic M. mystacinus and M. brandtii, M. alcathoe has never been found in an anthropogenic roost (except for a fissure in concrete electricity pole). Preliminary analysis of the diet showed that nematoceran flies were the most important prey item along with spiders, caddis flies, small moths and neuropterans. In the observed ecological characteristics, M. alcathoe markedly differs from other European species of the genus Myotis. Its restricted habitat requirements are perhaps responsible for an islet-like pattern of its distribution and suggest an essential conservation value of the habitats of its occurrence.

Craseonycteris thonglongyai (Chiroptera: Craseonycteridae) is a Rhinolophoid: Molecular Evidence from Cytochrome b

Craseonycteris thonglongyai (Chiroptera: Craseonycteridae), an enigmatic taxon which shares morphological traits with both Rhinopomatidae and Emballonuridae was for the first time investigated with the aid of molecular phylogenetic techniques. Three methods of phylogenetic inference, parsimony, maximum-likelihood, and Bayesian phylogenetics were used. Based on 402 bp of DNA sequence from the mitochondrial cytochrome b gene, placement of Craseonycteridae within the superfamily Rhinolophoidea was demonstrated. Our results also suggest close proximity of Craseonycteridae to Hipposideridae rather than to Rhinopomatidae, close relationships between Megadermatidae and Rhinolophidae, sister group position of Pteropodidae to Rhinolophoidea, and closer affiliation of Nycteridae with the infraorder Yangochiroptera. Spectral analysis was in agreement with all these outcomes except for closer relationships of Craseonycteris with Rhinopomatidae.

Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta

This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non‐functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non‐functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals.

Syntopic Occurrence in Turkey Supports Separate Species Status for Miniopterus schreibersii schreibersii and M. schreibersii pallidus (Mammalia: Chiroptera)

Miniopterus schreibersii is a complex, polytypic species group with a wide distribution ranging from Northern Africa, Southern Europe to Asia, the Solomon Islands and Northern Australia. Two subspecies previously recognized in Turkey, M. s. schreibersii and M. s. pallidus, differ significantly in nuclear and mitochondrial DNA, and in morphology. Until now, the distribution records of M. s. schreibersii and M. s. pallidus showed that they were allopatric and hence even though there was clear morphological and genetic differentiation between the two taxa, whether they represented separate species or subspecies was still not determined with certainty. Here we present the first data on syntopic occurrence of both forms in three caves in south-eastern Turkey. We show that the three caves host individuals of both taxa by using mitochondrial DNA, nuclear DNA and morphometric analyses. These findings provide the final line of evidence to date, for designation of M. s. schreibersii and M. s. pallidus as two separate species, M. schreibersii and M. pallidus. This will raise the number of species in the Eurobats agreement area from 45 to 46.