Franco Andreone

Vast underestimation of Madagascar's biodiversity evidenced by an integrative amphibian inventory

Amphibians are in decline worldwide. However, their patterns of diversity, especially in the tropics, are not well understood, mainly because of incomplete information on taxonomy and distribution. We assess morphological, bioacoustic, and genetic variation of Madagascars amphibians, one of the first near-complete taxon samplings from a biodiversity hotspot. Based on DNA sequences of 2,850 specimens sampled from over 170 localities, our analyses reveal an extreme proportion of amphibian diversity, projecting an almost 2-fold increase in species numbers from the currently described 244 species to a minimum of 373 and up to 465. This diversity is widespread geographically and across most major phylogenetic lineages except in a few previously well-studied genera, and is not restricted to morphologically cryptic clades. We classify the genealogical lineages in confirmed and unconfirmed candidate species or deeply divergent conspecific lineages based on concordance of genetic divergences with other characters. This integrative approach may be widely applicable to improve estimates of organismal diversity. Our results suggest that in Madagascar the spatial pattern of amphibian richness and endemism must be revisited, and current habitat destruction may be affecting more species than previously thought, in amphibians as well as in other animal groups. This case study suggests that worldwide tropical amphibian diversity is probably underestimated at an unprecedented level and stresses the need for integrated taxonomic surveys as a basis for prioritizing conservation efforts within biodiversity hotspots.

The Challenge of Conserving Amphibian Megadiversity in Madagascar

Highly diverse and so far apparently untouched by emergent diseases, Malagasy frogs nevertheless are threatened by ongoing habitat destruction, making pro-active conservation actions especially important for preserving this unique, pre-decline, amphibian fauna.

The Italian batrachofauna and its conservation status: a statistical assessment

Abstract The status of the Italian autochtonous batrachofauna has been analysed taking into consideration a set of 13 variables, ranging from natural history traits (e.g. type of reproduction, number of eggs, frequented habitat), to distribution and areal fragmentation, taxonomic uniqueness and insularity. Each variable was categorized into four ranks (0–3) of increasing risk for survival. Urodeles and anurans were treated separately for both univariate and multivariate analyses. The results confirm a general sensitivity of urodeles, although in many cases newts and salamanders may react more promptly to habitat alteration and human disturbance. On the other hand, the anurans, except for three species that are widely distributed and largely euryecious ( Bufo bufo, Rana temporaria, R. “esculenta” ), appear more sensitive than urodeles for a series of factors. Some anurans (such as Pelobates fuscus insubricus and R. latastei ) are restricted to low altitude habitats (which are in general more subject to alteration), or are restricted to islands. Conservation actions should be applied for protecting Salamandra lanzai, S. atra aurorae, the Sardinian plethodontids (genus Speleomantes ), and Euproctus platycephalus . For the anurans, the most endangered taxon appears to be P. fuscus insubricus , while some insular species such as Discoglossus pictus, D. sardus , and Hyla sarda should be carefully managed by the creation of protected areas.

Exploring the potential of life-history key innovation: brook breeding in the radiation of the Malagasy treefrog genus Boophis

The treefrog genus Boophis is one of the most species‐rich endemic amphibian groups of Madagascar. It consists of species specialized to breeding in brooks (48 species) and ponds (10 species). We reconstructed the phylogeny of Boophis using 16S ribosomal DNA sequences (558 bp) from 27 species. Brook‐breeders were monophyletic and probably derived from an ancestral pond‐breeding lineage. Pond‐breeders were paraphyletic. The disparity in diversification among pond‐breeders and brook‐breeders was notable among endemic Malagasy frogs, although it was not significant when considering Boophis alone. Sibling species which have different advertisement calls but are virtually indistinguishable by morphology were common among brook‐breeders; genetic divergence between these species was high (modal 8% total pairwise divergence). Substitution rates in brook‐breeding species were significantly higher than in pond‐breeders. Speciation of pond‐breeders may be hindered by their usually more synchronous reproduction and a higher vagility which enhances gene flow, while a higher potential of spatial segregation and speciation may exist along brooks.

Variations in age, size at maturity and gestation duration among two neighbouring populations of the alpine salamander (Salamandra lanzai)

We describe the age structures of two neighbouring terrestrial salamander populations. The skeletochronological method was also used on larvae in utero and on new-born individuals. The age of adults was 8‐24 years in population A, while males reached maturity at 3‐5 years old and the youngest females were 6 years old in population B. Males and females from population B were also larger than those in population A. For the first time, lines of arrested growth (LAGs) were also found in the humerus of intra-uterine larvae and new-born individuals, indicating that young can spend up to 3 years in utero (population B) and up to 4 years (population A) before hatching. Growth of adults (fitted by the Bertalanffy model) also exhibited differences in growth coefficient ( k ) and mean asymptotic length (SVLmax) between sexes and populations. Local climatic conditions differed between the two areas of these populations and we hypothesize that the number of rainy days directly influences foraging during the short period of activity (< 3 months), leading to a delay in age at maturity, smaller length and growth rate, and increased gestation duration in the drier environment. The discussion is focused on proximate environmental influences on the variation of length and associated life-history traits in ectotherms, especially in terrestrial salamanders.

Conservation priorities and potential threats influencing the hyper‐diverse amphibians of Madagascar

Abstract The conservation of Madagascan amphibians was assessed using a set of natural history parameters. The more than two hundred species were grouped into 51 operational conservation units to get more reliable results than those afforded by the low level of knowledge available for most of the species. Results in terms of ecological sensitivity were obtained by means of a univariate ranking and cluster analysis. Mantelline mantellids and cophyline microhylids were among the amphibians most sensitive, since they are closely related to a stable rainforest environment. The less sensitive species in terms of ecological preferences appeared to be those breeding in temporary ponds and living in dry‐arid and savannah‐like areas (e.g., Dyscophinae, Laliostoma labrosum, and Hyperoliidae). Other species, closely linked to the aquatic environment, are less affected by deforestation, and may occur in already degraded areas when a stream network and associated gallery forest still exist. For some genera (e.g., Mantella and Scaphiophrynè) the pet trade may constitute a threat (when dealing with already disturbed and restricted populations). In this sense, most Mantella species must be managed in terms of number of specimens exported. This is especially true for M. cowani and M. bernhardi, which have a very narrow distribution area. Mantella cowani is severely endangered, since it is a “plateau”; species, and suffers from a combination of both habitat degradation and capture for commerce. A principal component analysis on Ranidae, Boophinae, Mantellinae, Laliostominae, Dyscophinae, Scaphiophryninae, Cophylinae, and Hyperoliidae showed that the variables ordering the various taxa were activity type, distribution, and habitat breadth.

Malagasy scincid lizards: descriptions of nine new species, with notes on the morphology, reproduction and taxonomy of some previously described species (Reptilia, Squamata: Scincidae)

The taxonomy and/or natural history of 33 species of scincid lizards from Madagascar are reviewed. Most of the material, consisting of 187 specimens now housed in the Museo Regionale di Scienze Naturali, Turin, Italy, has been collected recently, but some dates to the 19th century. Nine new species are described in three genera: Amphiglossus mandady, A. nanus, A. spilostichus, A. stylu, A. tanysoma, Paracontias manify, P. hafa, P. tsararano and Pseudoacontiasmenamainty, increasing the known skink fauna of Madagascar (62 species) by 14.5%. All the new species come from the closed forests of north-eastern Madagascar. Additionally, Amphiglossus praeornatus is resurrected from the synonymy of A. frontoparietalis, and Androngo alluaudi, A. crenni and A. elongatus are transferred to the genus Amphiglossus. There is also a key to the species of Paracontias and a new interspecifically variable character for Mabuya. Information on morphological variation, basic reproductive biology, habits and habitats is provided, as available, for all species. Perhaps most interestingly, Amphiglossus nanus n. sp. represents the eighth skink lineage in which an oviduct has been lost and Amphiglossus melanopleura decreases the number of longitudinal scale rows at mid-body and the number of subdigital lamellae with altitude.

Natural history and larval morphology of Boophis occidentalis (Anura: Mantellidae: Boophinae) provide new insights into the phylogeny and adaptive radiation of endemic Malagasy frogs

During a zoological survey in north-west Madagascar (Sahamalaza Peninsula) we documented aspects of the natural history of Boophis occidentalis (formerly a subspecies of B. albilabris and here raised to species level). Individual age assessed by skeletochronology ranged from 4 to 11 years. Breeding behaviour was observed at a seasonal stream after heavy rainfalls: five choruses of eight to 90 males aggregated in shallow brook sections. The males emitted low frequency calls and engaged in scramble battles. Only two females were found. A couple laid a large number of eggs, attached as a single layer on submerged stones. Tadpoles reared from these eggs had the typical morphology of brook-breeding Boophis species with a 1:5+5/3 keratodont formula and a relatively flattened body. Adult males had an anteroventrally oriented cloaca, a morphological trait shared with B. albilabris. Advertisement calls were similar in general structure to those of B. albilabris recorded at Anjanaharibe-Sud. They were unharmonious and consisted of pulsed notes emitted at irregular intervals. Much lower pulse rates in B. albilabris (30‐38 pulses/s) than in B. occidentalis (90‐109 pulses/s) support the specific distinctness of these taxa. The combination of characters related to reproductive biology in B. occidentalis and B. albilabris is unique in Boophis. The acontinuous breeding behaviour and large number of eggs per clutch are traits found in the pond-breeding species of the B. tephraeomystax group, while larval morphology and habitat are characteristic of brook-breeding species. Available morphological and molecular data place B. albilabris and B. occidentalis into the brookbreeding Boophis radiation. The acontinuous timing of reproduction and large egg number may be secondary adaptations that allowed the species to colonize arid regions of western Madagascar.

Widespread presence of the pathogenic fungus Batrachochytrium dendrobatidis in wild amphibian communities in Madagascar

Amphibian chytridiomycosis, an emerging infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd), has been a significant driver of amphibian declines. While globally widespread, Bd had not yet been reported from within Madagascar. We document surveys conducted across the country between 2005 and 2014, showing Bds first record in 2010. Subsequently, Bd was detected in multiple areas, with prevalence reaching up to 100%. Detection of Bd appears to be associated with mid to high elevation sites and to have a seasonal pattern, with greater detectability during the dry season. Lineage-based PCR was performed on a subset of samples. While some did not amplify with any lineage probe, when a positive signal was observed, samples were most similar to the Global Panzootic Lineage (BdGPL). These results may suggest that Bd arrived recently, but do not exclude the existence of a previously undetected endemic Bd genotype. Representatives of all native anuran families have tested Bd-positive, and exposure trials confirm infection by Bd is possible. Bds presence could pose significant threats to Madagascars unique “megadiverse” amphibians.

Fossorial but widespread: the phylogeography of the common spadefoot toad (Pelobates fuscus), and the role of the Po Valley as a major source of genetic variability

Pelobates fuscus is a fossorial amphibian that inhabits much of the European plain areas. To unveil traces of expansion and contraction events of the species’ range, we sequenced 702 bp of the mitochondrial cytochrome b gene. To infer the population history we applied phylogeographical methods, such as nested clade phylogeographical analysis (NCPA), and used summary statistics to analyse population structure under a neutral model of evolution. Populations were assigned to different drainage systems and we tested hypotheses of explicit refugial models using information from analysis of molecular variance, nucleotide diversity, effective population size estimation, NCPA, mismatch distribution and Bayesian dating. Coalescent simulations were used as post hoc tests for plausibility of derived or a priori assumed biogeographical hypotheses. Our combination of all approaches enabled the reconstruction of the colonization history and phylogeography of P. fuscus and confirmed a previous assumption of the existence of two major genetic lineages within P. fuscus. Using the Afro‐European vicariance of Pelobates cultripes and Pelobates varaldii and applying Bayesian dating we estimated the divergence of these phylogeographical lineages to the Pliocene. We suggest the existence of three different glacial refugia: (i) the area between the Caspian and Black Seas as the origin for the expansion of the ‘eastern lineage’; (ii) the Danube system as a centre of diversity for part of the ‘western lineage’; (iii) the Po Valley, the largest centre of genetic variability. This fits the hypothesis that climatic fluctuation was a key event for differentiation processes in P. fuscus.