Patterns of endemism and species richness in Malagasy cophyline frogs support a key role of mountainous areas for speciation

Cophyline narrow-mouthed frogs (Anura: Microhylidae) are a diverse endemic radiation of Madagascar. Cophylines contain a high proportion of range restricted species and constitute a good model system to understand patterns of evolutionary diversification in tropical ecosystems. We combine spatial and phylogenetic analyses for a near-complete taxon sample to test competing explanations for patterns of species richness (SR) and endemism. Our reconstruction of the phylogeny of cophylines indicates the presence of 22 new species and several instances of nonmonophyly. We found a strong historical signal in current cophyline ranges indicating a high degree of spatial niche conservatism in clade diversification, with clades occurring in the North of Madagascar constituting the most derived in the phylogeny. We identified six positively correlated centers of SR and endemism that can neither be explained by stochastic models such as elevational or latitudinal mid-domain effect, nor by low-elevation river catchments. Instead, the locations of these centers in areas spanning a high altitudinal range in combination with specific climatic parameters support a key role of mountainous areas for speciation of these anurans, although we cannot exclude an influence of habitat loss due to human impact. High conservation priority is ascribed to these areas.     

The systematics and adaptations of some Papuan microhylid frogs which live underground

A taxonomic, anatomical and behavioural account is given of some burrowing microhylid frogs from New Guinea. Six species belonging to four genera are dealt with, of these four are described as new species. Two genera are removed from synonomy to accommodate four of the burrowing species. Histological and anatomical modifications to the head, which are associated with head-first burrowing, are described. The calls of the male frogs are described in detail and attention is drawn to the similarity of calls made by all burrowing species. This is discussed in relation to the problems of sound transmission below ground.     

Nuclear gene phylogeny of narrow-mouthed toads (Family: Microhylidae) and a discussion of competing hypotheses concerning their biogeographical origins

The family Microhylidae has a large circumtropic distribution and contains about 400 species in a highly subdivided taxonomy. Relationships among its constituent taxa remained controversial due to homoplasy in morphological characters, resulting in conflicting phylogenetic hypotheses. A phylogeny based on four nuclear genes (rag-1, rag-2, tyrosinase, BDNF) and one mitochondrial gene (CO1) of representatives of all currently recognized subfamilies uncovers a basal polytomy between several subfamilial clades. A sister group relationship between the cophylines and scaphiophrynines is resolved with moderate support, which unites these endemic Malagasy taxa for the first time. The American members of the subfamily Microhylinae are resolved to form a clade entirely separate from the Asian members of that subfamily. Otophryne is excluded from the subfamily Microhylinae, and resolved as a basal taxon. The placement of the Asian dyscophine Calluella nested within the Asian Microhyline clade rather than with the genus Dyscophus is corroborated by our data. Bayesian estimates of the divergence time of extant Microhylidae (47-90 Mya) and among the subclades within the family are discussed in frameworks of alternative possible biogeographic scenarios.     

Molecular phylogeny and biogeography of Malagasy frogs of the genus Gephyromantis

The genus Gephyromantis is a clade within the Malagasy-Comoroan family Mantellidae composed of rainforest frogs that live and breed to varying degrees independently from water. Based on DNA sequences of five mitochondrial and five nuclear genes we inferred the phylogeny of these frogs with full taxon coverage at the species level. Our preferred consensus tree from a partitioned Bayesian analysis of 5843 base pairs of 51 nominal and candidate species supports various major clades within the genus although the basal relationships among these remain unresolved. The data provide strong evidence for the monophyly of the subgenera Gephyromantis (after exclusion of Gephyromantis klemmeri), Laurentomantis, Vatomantis, and Phylacomantis. Species assigned to the subgenus Duboimantis belong to two strongly supported clades of uncertain relationships. G. klemmeri, previously in the subgenus Gephyromantis, was placed with high support sister to the Laurentomantis clade, and the Laurentomantis + G. klemmeri clade was sister to Vatomantis. A reconstruction of ancestral distribution areas indicates a diversification of several subgenera in the northern biogeographic regions of Madagascar and the dispersal out of northern Madagascar for several clades.     

Molecular phylogeny and karyotype differentiation in <Emphasis Type="Italic">Paratelmatobius</Emphasis> and <Emphasis Type="Italic">Scythrophrys</Emphasis> (Anura,Leptodactylidae)

Paratelmatobius and Scythrophrys are leptodactylid frogs endemic to the Brazilian Atlantic forest and their close phylogenetic relationship was recently inferred in an analysis that included Paratelmatobius sp. and S. sawayae. To investigate the interspecific relationships among Paratelmatobius and Scythrophrys species, we analyzed a mitochondrial region (approximately 2.4 kb) that included the ribosomal genes 12S and 16S and the tRNAval in representatives of all known localities of these genera and in 54 other species. Maximum parsimony inferences were done using PAUP* and support for the clades was evaluated by bootstrapping. A cytogenetic analysis using Giemsa staining, C-banding and silver staining was also done for those populations of Paratelmatobius not included in previous cytogenetic studies of this genus in order to assess their karyotype differentiation. Our results suggested Paratelmatobius and Scythrophrys formed a clade strongly supported by bootstrapping, which corroborated their very close phylogenetic relationship. Among the Paratelmatobius species, two clades were identified and corroborated the groups P. mantiqueira and P. cardosoi previously proposed based on morphological characters. The karyotypes of Paratelmatobius sp. 2 and Paratelmatobius sp. 3 described here had diploid chromosome number 2n = 24 and showed many similarities with karyotypes of other Paratelmatobius representatives. The cytogenetic data and the phylogenetic analysis allowed the proposal/corroboration of several hypotheses for the karyotype differentiation within Paratelmatobius and Scythrophrys. Namely the telocentric pair No. 4 represented a synapomorphy of P. cardosoi and Paratelmatobius sp. 2, while chromosome pair No. 5 with interstitial C-bands could be interpreted as a synapomorphy of the P. cardosoi group. The NOR-bearing chromosome No. 10 in the karyotype of P. poecilogaster was considered homeologous to chromosome No. 10 in the karyotype of Scythrophrys sp., chromosome No. 9 in the karyotype of Paratelmatobius sp. 1, chromosome No. 8 in the karyotypes of Paratelmatobius sp. 2 and of Paratelmatobius sp. 3, and chromosome No. 7 in the karyotype of P. cardosoi. A hypothesis for the evolutionary divergence of these NOR-bearing chromosomes, which probably involved events like gain in heteochromatin, was proposed.     

Alkaloid evolution and angiosperm systematics

The correlation of biosynthetic steps leading to the primary precursors of the shikimate pathway with the distribution of derived alkaloids on dahlgren's system of classification of angiosperm orders suggests that evolution paralleled gradual blocking of these steps. Phenylalanine-derived alkaloids, with the centre of radiation situated in the magnoliales, are of widespread occurrence in angiosperms, an indication of the antiquity of the character. Anthranilic acid-derived alkaloids, with the centre of radiotion in the rutales, are less widespread. Orders in which such alkaloids co-occur with the former biogenetic group are considered to be of more recent origin. Finally, mevalonate-derived iridoid alkaloids, with the centre of radiation in the gentianales, are even less widespread. Orders in which such alkaloids co-occur with the former biogenetic groups should thus be of still more recent origin. These concepts are summarized bg a phylogenetic tree, which illustrates the divergence of three major groups of angiosperm superorders.     

New insights into the systematics of Malagasy mongoose‐like carnivorans (Carnivora,Eupleridae, Galidiinae) based on mitochondrial and nuclear DNA sequences

The Malagasy carnivorans (Eupleridae) comprise seven genera and up to ten species, depending on the authority, and, within the past decades, two new taxa have been described. The family is divided into two subfamilies, the Galidiinae, mongoose‐like animals, and the Euplerinae, with diverse body forms. To verify the taxonomic status of Galidiinae species, including recently described taxa, as well as some recognized subspecies, we studied intrageneric genetic variation and structure, using both mitochondrial and nuclear markers. Our results suggest the recognition of four species in the Galidiinae, rendering each genus monospecific. We propose to recognize three subspecies in Galidia elegans (G. e. dambrensis, G. e. elegans, and G. e. occidentalis), two subspecies in Mungotictis decemlineata (M. d. decemlineata and M. d. lineata), and two subspecies in Galidictis fasciata (G. f. fasciata and G. f. grandidieri, the latter was recently described as a distinct species). Our results indicate also that Salanoia durrelli should be treated as a junior synonym of Salanoia concolor. Low levels of intraspecific divergence revealed some geographical structure for the Galidiinae taxa, suggesting that environmental barriers have isolated certain populations in recent geological time. All taxa, whether at the species or subspecies level, need urgent conservation attention, particularly those with limited geographical distributions, as all are threatened by forest habitat degradation.     

Malagasy cichlids differentially limit impacts of body shape evolution on oral jaw functional morphology

Patterns of trait covariation, such as integration and modularity, are vital factors that influence the evolution of vertebrate body plans. In functional systems, decoupling of morphological modules buffers functional change in one trait by reducing correlated variation with another. However, for complex morphologies with many‐to‐one mapping of form to function (MTOM), resistance to functional change may also be achieved by constraining morphological variation within a functionally stable region of morphospace. For this research, we used geometric morphometrics to evaluate the evolution of body shape and its relationship with jaw functional morphology in two independent radiations of endemic Malagasy cichlid (Teleostei: Cichlidae). Our results suggested that the two subfamilies used different strategies to mitigate impacts of body shape variation on a metric of jaw function, maxillary kinematic transmission (MKT): (1) modularity between cranial and postcranial morphologies, and (2) integration of body and jaw evolution, with jaw morphologies varying in a manner that limits change in MKT. This research shows that, unlike modularity, MTOM allows traits to retain strong evolutionary covariation while still reducing impacts on functionality. These results suggest that MTOM, and its influence on the evolution of correlated traits, is likely much more widespread than is currently understood.     

Phenotypic and genetic diversity in aposematic Malagasy poison frogs (genus Mantella)

Intraspecific color variation has long fascinated evolutionary biologists. In species with bright warning coloration, phenotypic diversity is particularly compelling because many factors, including natural and sexual selection, contribute to intraspecific variation. To better understand the causes of dramatic phenotypic variation in Malagasy poison frogs, we quantified genetic structure and color and pattern variation across three closely related species, Mantella aurantiaca, Mantella crocea, and Mantella milotympanum. Although our restriction site‐associated DNA (RAD) sequencing approach identified clear genetic clusters, they do not align with current species designations, which has important conservation implications for these imperiled frogs. Moreover, our results suggest that levels of intraspecific color variation within this group have been overestimated, while species diversity has been underestimated. Within major genetic clusters, we observed distinct patterns of variation including: populations that are phenotypically similar yet genetically distinct, populations where phenotypic and genetic breaks coincide, and populations that are genetically similar but have high levels of within‐population phenotypic variation. We also detected admixture between two of the major genetic clusters. Our study suggests that several mechanisms—including hybridization, selection, and drift—are contributing to phenotypic diversity. Ultimately, our work underscores the need for a reevaluation of how polymorphic and polytypic populations and species are classified, especially in aposematic organisms.     

New evidence for parallel evolution of colour patterns in Malagasy poison frogs (Mantella)

Malagasy poison frogs of the genus Mantella are diurnal and toxic amphibians of highly variable and largely aposematic coloration. Previous studies provided evidence for several instances of homoplastic colour evolution in this genus but were unable to sufficiently resolve relationships among major species groups or to clarify the phylogenetic position of several crucial taxa. Here, we provide cytochrome b data for 143 individuals of three species in the Mantella madagascariensis group, including four newly discovered populations. Three of these new populations are characterized by highly variable coloration and patterns but showed no conspicuous increase of haplotype diversity which would be expected under a scenario of secondary hybridization or admixture of chromatically uniform populations. Several populations of these variable forms and of M. crocea were geographically interspersed between the distribution areas of Mantella aurantiaca and Mantella milotympanum. This provides further support for the hypothesis that the largely similar uniformly orange colour of the last two species evolved in parallel. Phylogenies based on over 2000 bp of two nuclear genes (Rag-1 and Rag-2) identified reliably a clade of the Mantella betsileo and Mantella laevigata groups as sister lineage to the M. madagascariensis group, but did not support species within the latter group as monophyletic. The evolutionary history of these frogs might have been characterized by fast and recurrent evolution of colour patterns, possibly triggered by strong selection pressures and mimicry effects, being too complex to be represented by simple bifurcating models of phylogenetic reconstruction.     

Molecular systematics of mantelline frogs from Madagascar and the evolution of their femoral glands

Several genera of frogs from Madagascar, classified in the family Mantellidae, subfamily Mantellinae, possess structures commonly called 'femoral glands' on the ventral side of their shanks. The question arises as to the origin and phylogenetic significance of these glands. A molecular phylogeny based on 3601 nucleotide DNA sequences of three mitochondrial and two nuclear genes of 30 mantellid species provided strong support for monophyly of the included mantellines, all characterized by enlarged femoral gland clusters, as well as for those with gland clusters of coordinated central arrangement of secretion ducts. However, the phylogeny also strongly supported the hypothesis of convergent evolution of structurally similar glands in unrelated frogs ( Indirana , Petropedetes ), and several trends of convergent evolution of gland structure within mantellines. We studied the light microscopic structure of the femoral glands in a representative array of 18 mantellid species. Males of all species of the subfamily Mantellinae were characterized by clusters of distinct single glands. Each was structurally similar to an enlarged granular gland and secreted independently, probably through a single duct. By contrast, the largely semi-aquatic frogs in the genus Mantidactylus had a specialized cluster of glands, in which the secretion ducts led into a macroscopically recognizable central depression. In Boophis opisthodon , a mantellid species of the subfamily Boophinae without externally recognizable femoral glands, we observed a large number of enlarged granular glands of various sizes in the ventral skin of the shank. This observation is consistent with the hypothesis that the large and more uniform organs of mantellines are derived granular glands.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 529–539.     

Molecular phylogeny of Malagasy reed frogs, Heterixalus, and the relative performance of bioacoustics and color-patterns for resolving their systematics

The members of the genus Heterixalus constitute one of the endemic frog radiations in Madagascar. Here we present a complete species-level phylogeny based on DNA sequences (4876 base pairs) of three nuclear and four mitochondrial markers to clarify the phylogenetic relationships among and within all known species of this genus, as well as the phylogenetic position of the monospecific Seychellean Tachycnemis seychellensis. Although the performance to resolve supported clades of Heterixalus species differed among the investigated gene fragments when analyzed separately, we could identify five well-supported species groups within Heterixalus in the combined analysis of all gene fragments. Our data strongly support a Heterixalus-Tachycnemis clade, and indicate the probable monophyly of Heterixalus placed sister to Tachycnemis. However, the diversification of these lineages may have happened in a short interval of time, leading to an unstable placement of Tachycnemis in the single-gene fragment phylogenies. Referring to the hitherto existing classification of Heterixalus, which is predominantly based on chromatic and bioacoustic characters, we examined the relative performance of these data sets relative to our molecular phylogeny. A Bayesian tree reconstructed with a bioacoustic data set yielded a higher resemblance to the molecular phylogeny than a tree constructed using a chromatic data set, which supports the importance of bioacoustic characters for systematic analyses of these anurans.     

Phylogeny and systematics of Anatolian mountain frogs

Anatolian mountain frogs (Rana macrocnemis, Rana camerani, Rana holtzi, and Rana tavasensis) are one of the most specious amphibian groups in Turkey containing two endemic taxa (R. holtzi and R. tavasensis). The taxonomy of this group remains controversial as there are several unresolved issues.In the present study, we aimed to resolve the taxonomic uncertainty of the Anatolian mountain frogs through two mitochondrial genes (CYTB, 481 bp and COI, 743 bp) and two protein-coding nuclear genes (POMC, 401 bp and RAG1, 717 bp). The mitochondrial DNA (mtDNA) markers were found to be highly polymorphic in this group. Haplotype network analysis revealed that R. tavasensis was different for at least 33 and 52 mutational steps according to CYTB and COI gene regions, respectively. High bootstrap and posterior probability values obtained from the mtDNA genes support the idea that Anatolian mountain frogs are represented by two distinct species in Anatolia: R. macrocnemis and R. tavasensis. However, no genetic variation was detected according to nuclear DNA (nDNA) markers.The analysis of molecular variance (AMOVA) revealed no differences among the groups of R. macrocnemis, R. camerani, and R. holtzi. Despite the low genetic distance among R. macrocnemis, R. camerani, and R. holtzi species, the pairwise distances estimated from R. tavasensis were higher compared with other Anatolian mountain frog lineages.     

Genomic organization of repetitive DNAs in the cichlid fish <Emphasis Type="Italic">Astronotus ocellatus</Emphasis>

To contribute to the knowledge of fish genomes, we identified and characterized by means of nucleotide sequencing and physical chromosome mapping, three classes of repetitive DNAs in the genome of the South American cichlid fish Astronotus ocellatus. The first class corresponds to a satellite DNA family (AoSat) that shares similarity with a centromeric satellite DNA of the pufferfish Tetraodon nigroviridis. The second repetitive DNA class (AoRex3) is related to the retrotransposon Rex3, which is widely distributed among teleost fishes. The last repetitive element (AoLINE) shows a high similarity to the CR1-like LINE element of other teleosts. The three isolated repetitive elements are clustered in the centromeric heterochromatin of all chromosomes of the complement. The repetitive sequences are not randomly distributed in the genome, suggesting a pattern of compartmentalization on chromosomes.     

The evolution of primate communities and societies in Madagascar

During their 120 to 165 million years of isolation, the flora and fauna of Madagascar evolved, to a large extent, independently of the African mainland.¹ In contrast to other oceanic islands, Madagascar is large enough to house the major components of tropical ecosystems, allowing tests of evolutionary hypotheses on the level of complete communities. Taking lemurs, the primates of Madagascar, as an example, evolutionary hypotheses correctly predict the organization of their community structure with respect to ecological correlates. Lemur social systems and their morphological correlates, on the other hand, deviate in some respects from those of other primates. Apparently, lemur social systems are influenced by several selection pressures that are weak or rare in other primates. These include variable activity patterns and avoidance of infanticide. The interspecific variation in lemur social systems therefore offers a unique opportunity for a comprehensive study of the determinants of primate social systems.     

Early Holocene chronology and environment of Ampasambazimba,A Malagasy subfossil lemur site

According to a traditional but hitherto untested reconstruction of Madagascar’s Holocene environment, continuous forest preceded the monotonous grassland formations that now cover most of the island’s interior. Preliminary analyses of pollen samples collected near¹⁴C-dated horizons at Ampasambazimba (central Madagascar) indicate that a mosaic of woodlands, bushlands, and savanna existed close to this important vertebrate subfossil site around 7000–8000 BP. Although most members of Madagascar’s recently extinct “subfossil” fauna are thought to have been forest dwellers, several may have preferred a more open habitat like the one inferred for the region of Ampasambazimba. Dry savanna-woodland burns more readily than does dense forest and may have been more severely affected by the forces which transformed the Malagasy environment during the later Holocene. If so, the loss of savanna-woodland, not dense forest, may have been an important factor in the subfossil extinctions.     

Pair-specific usage of sleeping sites and their implications for social organization in a nocturnal Malagasy primate, the Milne Edwards' sportive lemur (Lepilemur edwardsi)

Safe sleeping sites may be a limited resource crucial for survival. In order to investigate their potential significance for social organization in nocturnal primates, we analyzed the spatial distribution of daily sleeping sites, their characteristics, their usage, and sleeping group compositions in the nocturnal Milne Edwards' sportive lemur during a 6-month field study in the dry deciduous forest of northwestern Madagascar. Sexes did not differ either in body size or in body mass. Sleeping sites were used almost exclusively by adult male-female pairs. Individuals showed a high sleeping-site fidelity limited to 2-3 different sleeping sites in close vicinity during the whole study period. Most females showed a higher fidelity to one distinct sleeping site than their male partners. Sleeping groups consisted of one adult male and one adult female and remained stable in composition over the whole study period. Exclusive pair-specific usage of sleeping sites suggests sleeping site related territoriality of male-female pairs, perhaps influenced by inter- and intrasexual resource competition. Results give first insights into the distribution patterns and social organization of this species. They imply dispersed monogamy for the Milne Edwards' sportive lemur, with sleeping sites as a potentially restricted and defendable resource.     

海南隔距兰属植物6个种的核型分析

采用压片法对海南产隔距兰属植物6个种,即：大序隔距兰Cleisostoma paniculatum（ker—Gawl．）Garay、短序隔距兰C．striatum（Rchb.f．）Garay、短茎隔距兰C.parishii（Hook．f.）Garay、金塔隔距兰C．filiforme,（Lindl．）Garay、尖喙隔距兰C.rostratum（Lodd．）Seidenf．、红花隔距兰C．williamsonii（Rchb．f）Garay的染色体数目和核型进行了研究。结果如下：大序隔距兰2n=2x=38：36m＋2sm;短序隔距兰2n=2x=38=2M＋36m;短茎隔距兰2n=2x=38=2M＋34m＋2sin;金塔隔距兰2n=2x=38=38m;尖喙隔距兰2n=2x=38=36m＋2sin;红花隔距兰2n=2x=38=34m＋4sm（2SAT）。主要由正中部着丝点区染色体组成。除尖喙隔距兰核型分类为1A型外,其他的都为1B型。