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Aim Location Time Period Major Taxa Studied Methods Results Main Conclusions There is an urgent need to explore, characterize, describe and preserve as many species as possible to prevent their decline. Tropical biodiversity hotspots harbour most of the known land diversity and vast amounts of undiscovered and undescribed species. Here, we quantify the taxonomically unassessed amphibian species richness in Madagascar, one of the best‐studied and explored tropical hotspots worldwide, to identify knowledge gaps and conservation implications.Madagascar.Present.Amphibians.We used the Madagascar amphibian fauna as a model to unveil neglected diversity by analysing 10,873 mitochondrial sequences using species delimitation algorithms and incorporating all previously published bioacoustics, distributional, morphological and nuclear data with an integrative approach.Besides the currently described 413 species, we identified 408 divergent lineages. Among this, 310 fit the category of candidate species pending a taxonomic assessment, while 98 are considered deep conspecific lineages. These figures suggest that species richness could be twice as high as represented in the current taxonomy. Geographically, most of these candidate species occur in well‐studied areas within the island.Despite being one of the best‐studied and explored tropical countries worldwide for amphibians, we found that many species are awaiting a taxonomic assessment in Madagascar. Paradoxically, this unassessed diversity concentrates on highly explored regions, emphasizing the importance of exploring and inventorying new areas. Our results highlight the magnitude of the Linnean and Wallacean shortfalls, affecting both species richness estimates and the distribution ranges and biogeographic setting known for this fauna. Current conservation efforts should consider this novel diversity and unexplored areas as they will likely harbour yet many new species to be discovered. We expect similar patterns across less studied tropical realms and encourage researchers to perform such studies in different clades before this neglected biodiversity becomes irremediably lost. [ABSTRACT FROM AUTHOR]

Steroid hormones play a pivotal role in shaping arthropod phenotypes, with 20‐hydroxyecdysone (20E) serving as a key regulator of molting, a vulnerable period in an insect's lifecycle. Despite its critical role in arthropod growth and development, the influence of 20E on arthropod behavior, particularly defensive strategies, remains poorly understood. We investigated the impact of 20E on the bioacoustic characteristics of hisses in the Madagascar hissing cockroach (Gromphadorhina portentosa), a social species with multiple complex acoustic signals. With increased 20E, we predicted that hiss production would be more likely and more defensive (i.e., longer hisses with greater intensity (dB) and reduced frequency (Hz)). We injected male G. portentosa with either a low‐ (35 μg) or high‐dose (70 μg) of 20E or a control (0 μg 20E), and we measured the presence/absence of hissing responses and their bioacoustic characteristics following a standardized tactile stimulus. Contrary to our prediction, there was no difference in the likelihood of hissing or hiss duration with 20E administration. However, administering 20E resulted in reduced hiss intensity and increased hiss frequency (as measured by peak and center frequencies), suggesting potential shifts from defensive to aggressive signaling. Our study contributes to the limited knowledge of the behavioral effects of 20E, suggesting that some arthropods may experience increased aggression or energetic limitations to defense during molting. Behavioral changes elicited by hormones have important implications for both fundamental ecology and applied pest management. [ABSTRACT FROM AUTHOR]

A range-wide assessment of genetic variation in one mitochondrial (16S rRNA) and one nuclear-encoded (Rag-1) gene fragment of the widespread Madagascar frog Blommersia blommersae revealed the presence of up to 12 deep genetic lineages. Many of these differed by genetic distances >3% in the 16S gene. In the Ranomafana area in the southern central east of Madagascar, two mitochondrial lineages differing by 1.2–1.8% in 16S occurred in close syntopy across multiple sites. A phylogeny of representative samples based on multiple mitochondrial genes supported three main mitochondrial clades within B. blommersae, with lineages from the (i) north, (ii) north and northern central east, and (iii) southern central east, respectively. In addition, one lineage from Sainte Luce in the south-east was sister to all other species of Blommersia, and thus clearly not belonging to B. blommersae, to which it has been tentatively assigned previously. Except for the Sainte Luce population, most of the mitochondrial lineages did not show a concordant and consistent differentiation in Rag-1 and no obvious morphological differences were detected among the lineages. We therefore refrain from taxonomic conclusions for them at this time, although indications exist that the populations from the northern central east and southern central east may show certain differences in relative note duration of advertisement calls, which require further study. However, the Sainte Luce individuals were highly divergent in 16S (>10%) and Rag-1, phylogenetically isolated, and characterised by differences in colour pattern. This lineage represents the most evolutionarily divergent species of Blommersia known to date and is herein formally named and described as Blommersia dupreezi sp. nov. [ABSTRACT FROM AUTHOR]

The Malagasy genus Gephyromantis contains 51 species of primarily terrestrial or scansorial frogs. Although many species are morphologically weakly divergent from each other, the combination of molecular and bioacoustic evidence has led to a continuous flow of species discoveries in the last years. Previous works have notably shown the existence of numerous additional deep mitochondrial lineages of uncertain status in the nominal subgenus Gephyromantis, some of these considered as confirmed or unconfirmed candidate species, some as deep conspecific lineages. Here we use DNA sequences of one mitochondrial and one nuclear marker, as well as morphological and bioacoustic data, to conduct an integrative revision of the subgenus Gephyromantis. The analyses reveal at least 12 distinct and independent evolutionary lineages belonging to the G. blanci and G. boulengeri species complexes. Evidence for the species status of these lineages included multiple cases of syntopic occurrence without genetic admixture, as well as differences in advertisement calls or morphological differentiation without intermediate forms, suggesting reproductive isolation. We discuss the relevance of these different lines of evidence and describe six new species of Gephyromantis. [ABSTRACT FROM AUTHOR]

The study of how animals adapt their behaviors depending on weather variables has gained particular significance in the context of climate change. This exploration offers insights into endangered species' potential threats and provides information on the direction to take in conservation activities. In this context, noninvasive, cost-effective, and potentially long-term monitoring systems, such as Passive Acoustic Monitoring (PAM), become particularly appropriate. Our study investigates the relationship between weather variables and the vocal behavior of Indri indri, the sole singing lemur species, within Madagascar's Maromizaha New Protected Area. Using PAM, we explore the factors shaping the vocalization patterns of this primate species in response to some environmental factors in their natural habitat. Analysis of an extensive audio data set collected across different years revealed the differential influence of temperature and precipitation on Indri indri vocal activity. We found that rainfall negatively influenced the emission of the vocalizations while warmer temperatures correlated with a greater emission of songs. The various environmental factors we considered also affected the timing of vocal emissions, showing the same pattern. Furthermore, our study confirms, once again, the strength of PAM as a valuable tool for studying vocal animal communication quickly, giving us information about long-term behavioral patterns that would be difficult to get in other ways. This research gives us further valuable information about how indris use vocalizations in their environment and how they adjust to environmental changes., (© 2024 The Author(s). American Journal of Primatology published by Wiley Periodicals LLC.)

Although molecular methods and bioacoustical analysis have been used to uncover cryptic species, the combination of both methodologies is still rare. The humbug damselfish complex, Dascyllus aruanus , is composed of at least two species with Dascyllus aruanus in the Pacific Ocean and Dascyllus abudafur in the Indian Ocean. However, genetic data suggest that additional species could be found. Therefore, we aimed to determine whether the sounds produced by different populations of fish could help to distinguish cryptic species. Recordings of chase and courtship sounds were made on humbug damselfish populations from Madagascar, Taiwan and French Polynesia. Chase sound features are more variable than courtship sounds, suggesting more constraints on courtship sounds, since they would contribute to premating isolation. Comparison between courtship sounds show the variation in acoustic features between Taiwan and Madagascar align with genetic differences, supporting that sounds could discriminate cryptic species in Teleosts. Moreover, differences in both acoustic features and genetic data are also found between Taiwan and French Polynesia, suggesting two clearly distinct populations. Consequently, the name D. emamo can be resurrected for the Polynesian humbug damselfish. External phenotype traits do not allow the distinction between populations, illustrating that only behaviour has been modified. [ABSTRACT FROM AUTHOR]

The stump-toed frogs of the Madagascar-endemic genus Stumpffia are mostly diminutive in size, but there is one group of comparatively large frogs within the genus, which we herein refer to as the Stumpffia hara species group. Each of the four known members of this species group is endemic to a single location of deciduous dry forest with exposed karstic limestone rock. Here, we report on the discovery of members of this species group on Montagne d'Ambre, a rainforest-covered extinct volcano in the North of Madagascar that has a rich Stumpffia fauna but has been thought to lack members of the S. hara species group until now. We found two members of the species group, one at the peak, and one in transitional and dry deciduous forest on the west and northern slopes of the mountain. The high-elevation species is new to science, and we here describe it as Stumpffia bishopi sp. nov. It occupies a highly distinct position in the phylogeny of these frogs, characterized by = 9.8% uncorrected pairwise distance from all other nominal Stumpffia in a fragment of the mitochondrial 16S rRNA gene. It is also the smallest of the members of the S. hara species group. Our genetic results show that the low-elevation species is Stumpffia megsoni, constituting a range expansion of that species and considerably expanding our understanding of its morphology and ecology. We report its advertisement call for the first time. Our results highlight the importance of continued surveys of even well-sampled localities, with special attention on the high elevation sites of northern massifs and collection of voucher specimens, and how much there still remains to understand about even the largest of Madagascar's small frogs. [ABSTRACT FROM AUTHOR]

Bioacoustics can be a non-invasive, cost-effective way of studying echolocating bats, and is especially useful for detecting and identifying rare or cryptic species. The insectivorous bats of Madagascar are understudied in comparison to the rest of the island's fauna, and very little is known about their habitat use. Here, we used a remote bioacoustic surveying technique in a bat survey of the Sahamalaza-Îles Radama National Park, northwest Madagascar, to study constant frequency echolocating bats (Hipposideridae and Rhinonycteridae). We used two passive acoustic monitoring units to automatically record bat activity from dusk until dawn in a range of habitat types that are characteristic of the region. Analysis of call acoustic parameters revealed three distinct constant-frequency phonic types within the national park, which we identified as Commerson's leaf-nosed bat (Macronycteris commersoni), the red trident bat (Triaenops menamena) and an unknown phonic type of ca. 78 kHz. We found significant differences in the habitat usage of these three species, suggesting species-specific habitat preferences among Madagascar's bats. Our statistical analyses revealed significant differences between the acoustic echolocation calls of these three phonic types. The 78 kHz calls do not match any of the other constant frequency-calling bat species currently described for Madagascar, indicating either acoustic divergence among bat sub-populations or the possible existence of a new undescribed species. These results highlight the need for increased survey efforts to gain an understanding of species-specific geographic distributions and habitat usage among Malagasy bats and to disentangle their cryptic species complexes. [ABSTRACT FROM AUTHOR]

Baleen whales face the challenge of finding patchily distributed food in the open ocean. Their relatively well-developed olfactory structures suggest that they could identify the specific odours given off by planktonic prey such as krill aggregations. Like other marine predators, they may also detect dimethyl sulfide (DMS), a chemical released in areas of high marine productivity. However, dedicated behavioural studies still have to be conducted in baleen whales in order to confirm the involvement of chemoreception in their feeding ecology. We implemented 56 behavioural response experiments in humpback whales using two food-related chemical stimuli, krill extract and DMS, as well as their respective controls (orange clay and vegetable oil) in their breeding (Madagascar) and feeding grounds (Iceland and Antarctic Peninsula). The whales approached the stimulus area and stayed longer in the trial zone during krill extract trials compared to control trials, suggesting that they were attracted to the chemical source and spent time exploring its surroundings, probably in search of prey. This response was observed in Iceland, and to a lesser extend in Madagascar, but not in Antarctica. Surface behaviours indicative of sensory exploration, such as diving under the stimulus area and stopping navigation, were also observed more often during krill extract trials than during control trials. Exposure to DMS did not elicit such exploration behaviours in any of the study areas. However, acoustic analyses suggest that DMS and krill extract both modified the whales’ acoustic activity in Madagascar. Altogether, these results provide the first behavioural evidence that baleen whales actually perceive prey-derived chemical cues over distances of several hundred metres. Chemoreception, especially olfaction, could thus be used for locating prey aggregations and for navigation at sea, as it has been shown in other marine predators including seabirds. [ABSTRACT FROM AUTHOR]

We describe a new species of the genus Gephyromantis, subgenus Vatomantis (Mantellidae, Mantellinae), from moderately high elevation (1164-1394 m a.s.l.) on the Marojejy, Sorata, and Andravory Massifs in northern Madagascar. The new species, Gephyromantis (Vatomantis) lomorina sp. n. is highly distinct from all other species, and was immediately recognisable as an undescribed taxon upon its discovery. It is characterised by a granular, mottled black and green skin, reddish eyes, paired subgular vocal sacs of partly white colour, bulbous femoral glands present only in males and consisting of three large granules, white ventral spotting, and a unique, amplitude-modulated advertisement call consisting of a series of 24-29 rapid, quiet notes at a dominant frequency of 5124-5512 Hz. Genetically the species is also strongly distinct from its congeners, with uncorrected pairwise distances =10 % in a fragment of the mitochondrial 16S rRNA gene to all other nominal Gephyromantis species. A molecular phylogeny based on 16S sequences places it in a clade with species of the subgenera Laurentomantis and Vatomantis, and we assign it to the latter subgenus based on its morphological resemblance to members of Vatomantis. We discuss the biogeography of reptiles and amphibians across the massifs of northern Madagascar, the evidence for a strong link between Marojejy and Sorata, and the role of elevation in determining community sharing across this landscape. [ABSTRACT FROM AUTHOR]

We describe two new microhylid frog species of the genus Rhombophryne from the humid forests of northeastern Madagascar: Rhombophryne botabota sp. n. and R. savaka sp. n. The former is a medium-sized species, characterised by darkened lateral sides of the head (present in only one other congener, R. laevipes) and a unique combination of morphological, osteological, and molecular characters. The latter is a rather small species, characterised by medially undivided vomerine teeth with two large lateral diastemata, and presence of inguinal spots. Rhombophryne savaka sp. n. is the first species of the genus known from Makira Natural Park, and is reported also from Marojejy National Park and Ambolokopatrika (Betaolana Forest). Although its distribution range is relatively large compared to those of congeners, its known extent of occurrence is less than 2,000 km². As deforestation and habitat degradation persist as threats despite formal legal protection, we suggest an IUCN Red List status of Vulnerable for this species. Rhombophryne savaka sp. n. is possibly endemic to the Marojejy National Park, like several other Rhombophryne species, but is unusual in being found at a relatively low altitude. As such, it is likely to be at high risk of habitat loss and decreasing range, and we propose a status of Endangered for it. We discuss the affinities of these new species and the variability of calls in this genus. [ABSTRACT FROM AUTHOR]

The acoustic structure of primate loud calls can be used as a powerful, inexpensive, and noninvasive tool for intra- and interspecific comparative analyses, reconstruction of phylogeny, and primate surveys. Despite the range of possibilities offered by acoustic analysis, only few studies so far have focused on quantitative descriptions of the acoustic structure of primate loud call repertoires. Here we aimed to assess the vocal repertoire of the solitary Sahamalaza sportive lemur, Lepilemur sahamalazensis, and to investigate potential communication functions. We recorded every sportive lemur vocalization we heard during 1000 h of nocturnal observations of eight collared individuals, as well as opportunistic searches in the Ankarafa Forest, Sahamalaza Peninsula in northwest Madagascar. In addition, we used playback experiments with four call types to clarify call function. We measured both temporal and spectral properties to describe calls quantitatively and used cross-validated discriminant function analysis to validate call types that we identified from a preliminary qualitative inspection of the spectrograms of 107 calls. We identified six distinct loud call types with the possibility of a seventh call type, with six loud call types similar to those of Lepilemur edwardsi and two loud call types similar to those of four other sportive lemur species. The described call types most likely function in mate advertisement, offspring care, and territorial defense. Future studies of loud calling of the Sahamalaza sportive lemur are needed to clarify if certain call types are sex specific and if loud calls could be used for recognition of individuals to enable noninvasive density measurements and species monitoring. [ABSTRACT FROM AUTHOR]

Although important advances have been made in recent years in the taxonomy of different families and subfamilies of Malagasy bats, those belonging to the Vespertilioninae remain partially unresolved. Herein using a mitochondrial marker (cytochrome b) as the point of departure for 76 specimens of Malagasy vespers and appropriate African taxa, we diagnose the six taxa of this subfamily on the island by overlaying different morphological and bioacoustic characters on the clade structure of sequenced animals. The species include: endemic Neoromicia matroka, which is sister to African N. capensis; endemics N. malagasyensis and N. robertsi, which form sister species; a member of the genus Hypsugo, which is sister to African H. anchietae and described herein as new to science; Pipistrellus hesperidus for which Madagascar animals are genetically close but distinct from African populations of the same species; and endemic P. raceyi, which shows segregation of eastern (mesic) and western (dry) populations and its sister species relationships are unresolved. While the external and craniodental measurements, as well as bioacoustic variables, allow only partial differentiation of these six species of Vespertilioninae, molecular characters provide definitive separation of the taxa, as do male bacular morphology. © 2015 The Linnean Society of London [ABSTRACT FROM AUTHOR]

Molecular phylogenetic studies suggest that the genus Emballonura, a member of the Old World tribe Emballonurini (Family Emballonuridae), is paraphyletic. This genus has a broad distribution across islands in the Indo-Pacific, southern Asia, and Madagascar. The paraphyly is the result of the genus Coleura, known from sub-Saharan Africa, portions of the Arabian Peninsula, Madagascar, and the Seychelles, being embedded between the Malagasy and Asian/Indo-Pacific clades of Emballonura, and the latter clade has priority for the use of the name. To resolve this situation, we propose a new genus for the Malagasy Emballonura clade. Furthermore, with greater molecular sampling of Coleura across portions of its range in association with morphological and bioacoustical characters, we are able to resolve aspects of the phylogenetic history and species limits of this genus. Coleura contains two well supported clades, including C. afra from mainland Tanzania and the offshore island of Pemba and a sister clade composed of C. cf. afra from Madagascar and C. seychellensis from the Seychelles. The average genetic distance between animals from Madagascar and the Seychelles is 6%, whereas Pemba/Tanzania and Madagascar is 10%. Because of the paraphyletic relationship of populations of C. afra with respect to C. seychellensis, we describe a new species of Coleura from Madagascar. [ABSTRACT FROM AUTHOR]

The Strict Nature Reserve of Betampona protects one of the last remaining relicts (about 2,228 ha) of low elevation rainforests in eastern Madagascar. Yet little has been previously published about the amphibian fauna of this rainforest. During 2004 and 2007, Betampona was surveyed over a total period of 102 days. Frogs were searched by opportunistic searching, pitfall trapping and acoustic surveys. The survey work confirmed the occurrence of 76 taxa, of which 36 are currently candidate species and about 30% were first considered as undescribed species. The identification of species included a multidimensional and integrative approach that links morphology, bioacoustics, ecology and genetics. Of these taxa, 24 species are potentially endemic to this low elevation eastern region. Considering the relatively small area of the Betampona forest, and its narrow elevational range, 76 amphibian species represents an unusually high richness compared to other sites in Madagascar. Although the eastern region is now largely deforested, our results reveal the importance of this relict forest, which is protecting a diverse amphibian fauna that includes many potentially endemic species. [ABSTRACT FROM AUTHOR]

Anuran vocalizations have a broad role in communication. In many cases, some calls help to avoid escalation to aggressive interactions that are energetically costly. The calling activity and agonistic behaviour of a Guibemantis sp. aff. bicalcaratus are here reported based on observations made at the Réserve Naturelle Intégrale de Betampona, East Madagascar. In addition, we describe a novel “aggressive” call type, produced to challenge territorial intruders. [ABSTRACT FROM AUTHOR]

The number of Miniopterus bat species on Madagascar and the nearby Comoros islands (Malagasy region) has risen from four to 11. These recently described cryptic taxa have been differentiated primarily based on molecular markers and associated a posteriori morphological characters that corroborate the different clades. Members of this Old World genus are notably conservative in morphology across their range. Several sites on Madagascar hold up to four small-bodied taxa of this genus that are morphologically similar to one another, although they can be distinguished based on the tragus, an ear structure associated with echolocation. Miniopterus often emit species-specific calls. In the present study, we analyze the bioacoustics of the 11 species of Miniopterus currently recognized from the Malagasy region, with an initial identification of the 87 recorded and collected individuals based on molecular markers and certain morphological characters. In most cases, bioacoustic parameters differentiate species and have taxonomic utility. Miniopterus griveaudi populations, which occur on three islands (Madagascar, Anjouan, and Grande Comore), showed no significant differences in peak echolocation frequencies. After running a discriminant function analysis based on five bioacoustic parameters, some mismatched assignments of Malagasy species were found, which include allopatric sister-taxa and sympatric, phylogenetically not closely-related species of similar body size. Because the peak echolocation frequencies of two species ( Miniopterus sororculus and Miniopterus aelleni) were independent of body size, they were acoustically distinguishable from cryptic sympatric congeners. The small variation around the allometric relationship between body size and peak echolocation frequency of Malagasy Miniopterus species suggests that intraspecific communication rather than competition or prey detection may be the driver for the acoustic divergence of these two species. Our well-defined echolocation data allow detailed ecological work to commence aiming to test predictions about the relative roles of competition, prey availability, and social communication on the evolution of echolocation in Malagasy Miniopterus species. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104, 284-302. [ABSTRACT FROM AUTHOR]

The article describes a new species of treefrog from southeastern Madagascar, Boophis quasiboehmei sp. n., that is highly similar in external adult morphology, bioacoustics and colouration to Boophis boehmei except for a differentiation in a fragment of the mitochondrial 16S ribosomal (RNA) gene. The reseachers concluded that the differentiation is concordant with the pattern in two nuclear genes showing no haplotype sharing of the new species with B. boehmei and with a consistent difference in tadpole morphology. The Boophis quasiboehmei sp. n. group of treefrogs contains several more cryptic species.

We provide a partial revision of the microhylid frogs of the genus Anodonthyla, endemic to Madagascar, based on comprehensive molecular, bioacoustic and morphological data sets that include newly collected specimens from multiple localities. The molecular trees provide strong evidence for the polyphyly of several nominal species as they were previously defined, especially of Anodonthyla boulengeri and A. nigrigularis. As a consequence, we here resurrect the nomen Mantella pollicaris Boettger as Anodonthyla pollicaris from the synonymy of A. boulengeri, and we describe four new species, all with strong genetic divergences to other nominal species: Anodonthyla emilei from Ranomafana National Park, a comparatively medium-sized species characterized by a multi-note advertisement call with high note repetition rate; A. theoi from Manombo Special Reserve, a small species characterized by low note repetition rate, long note duration and high spectral call frequency; A. vallani, a medium-sized species from Ambohitantely Special Reserve, characterized by low note repetition rate, long note duration and low spectral call frequency; and A. jeanbai, a small species from Andohahela National Park, characterized by a long and narrow head, presence of short dorsolateral folds, a very short first finger, and a yellowish ventral colour. A further candidate species comprises populations previously assigned to A. boulengeri from the Ranomafana region, which we do not describe because the corresponding data set is too fragmentary, and we refer to it as A. sp. aff. boulengeri 'Ranomafana'. The molecular phylogeny indicates recurrent shifts between high and low note repetition rates in calls, based mainly on three strongly supported sister groups: A. moramora with low repetition rate and A. nigrigularis with moderately low repetition rate; A. theoi with low repetition rate and A. pollicaris with high repetition rate; and A. vallani with low repetition rate and A. sp. aff. boulengeri 'Ranomafana' with high repetition rate. The two species with the northernmost ranges, A. hutchisoni and A. boulengeri, are phylogenetically nested within clades of species occurring further south, confirming that the center of origin of the genus Anodonthyla was most likely in the South East of Madagascar. [ABSTRACT FROM AUTHOR]

The article discusses the result of a study which described the spectral and temporal features of echolocation calls produced by 15 insectivorous bat species in three families of forest bats from Madagascar. A collection of bat vocalizations that can be used for acoustic inventories were provided. They involve heterodyne and time-expansion bat detectors to analyze time-expanded recordings of calls from 153 bats from 15 species. The study suggests that the combination of echolocation call structure and wing morphology are important indicators of foraging ecology which may lead to a better understanding of the ecology of Madagascar's bats.

Presents a study that analyzed the genetic and bioacoustic variability in Mantidactylus granulatus, a semi-arboreal frog species endemic to the northern portion of Madagascar. Examination of inter-regional differences of advertisement calls attributed to the species from several biogeographic regions in the northern part of the country; Description of distinct call and genetic features of Tsaratanana Massif, Mantidactylus zanova; Morphological comparison of M. zanova and M. granulatus.