Animal translocations provide striking examples of the human footprint on biodiversity. Combining continental-wide genomic and DNA-barcoding analyses, we reconstructed the historical biogeography of the Asian black-spined toad (Duttaphrynus melanostictus), a toxic commensal amphibian that currently threatens two biodiversity hotspots through biological invasions (Wallacea and Madagascar). The results emphasize a complex diversification shaped by speciation and mitochondrial introgression that comprises two distinct species. One species (true D. melanostictus) is distributed in the Indian subcontinent and is invasive in Wallacea. The other species, whose nomenclature remains unsettled, diverged from D. melanostictus in the Miocene era (~7 Mya) and diversified across Southeast Asia, from where it was introduced to Madagascar. Remarkably, the Indonesian population of D. melanostictus was recently established from India, which suggests historical, possibly human-assisted dispersal across the Bay of Bengal, reflecting the centuries-old connection between these regions.
The area around the Malagasy village of Andasibe, which includes Analamazaotra-Mantadia National Park as well as other protected areas, is characterized by very species-rich and well-studied communities of animals and plants, but new species are still regularly discovered. Three species of phytotelmic frogs of the subgenus Pandanusicola in the genus Guibemantis are known from this area, G. flavobrunneus, G. liber, and G. pulcher. Further Pandanusicola frogs from this area have been provisionally assigned to G. bicalcaratus or G. albolineatus, pending detailed taxonomic review. During preliminary exploration of the ecology of these specialized frogs that live and reproduce in the leaf axils of Pandanus screw pines, we noticed the syntopic presence of two differently colored and differently sized Pandanusicola in Andasibe that could not be unambiguously assigned to any known species. A genetic screening revealed that these correspond to yet two further species in the area. Based on our data, seven species of Pandanusicola occur in Andasibe and nearby forests: (1) G. liber, the only non-phytotelmic species of the subgenus in the region; (2) G. flavobrunneus which is the largest species and characterized by a diagnostic yellowish brown dorsal pattern; (3) G. pulcher, characterized by translucent-green color with purplish brown spotting not observed in any other species in the area; (4) G. methueni, a brownish species usually lacking contrasted dorsolateral bands that differs from the other species in the area by emitting a characteristic trill-like advertisement call series (rather than clicks or chirps) and according to our data is widespread along Madagascar’s east coast; as well as three new species: (5) G. ambakoana sp. nov., a brownish species, typically with contrasted incomplete light dorsolateral bands and with single click-like advertisement calls; (6) G. vakoa sp. nov., a species that is equally brownish but lacks contrasted light dorsolateral bands and that has single click-like advertisement calls of very short duration; and (7) G. rianasoa sp. nov., a species that is smaller sized and has less distinct femoral glands than all the others, and emits a short series of soft chirp-like advertisement calls. All these species are genetically highly distinct, with >5% uncorrected pairwise distances in the mitochondrial 16S rRNA gene, and lack of haplotype sharing in two nuclear-encoded genes. The co-occurrence of seven Pandanusicola frogs in a relatively small geographic area is unprecedented in Madagascar and calls for in-depth studies of a possible differentiation in habitat use and life history.
Turtle body size is associated with demographic and other traits like mating success, reproductive output, maturity, and survival. As such, growth analyses are valuable for testing life history theory, demographic modeling, and conservation planning. Two important but unsettled research areas relate to growth after maturity and growth rate variation. If individuals exhibit indeterminate growth after maturity, older adults may have an advantage in fecundity, survival, or both over younger/smaller adults. Similarly, depending on how growth varies, a portion of the population may mature earlier, grow larger, or both. We used 23-years of capture-mark-recapture data to study growth and maturity in the Spotted Turtle (Clemmys guttata), a species suffering severe population declines and for which demographic data are needed for development of effective conservation and management strategies. There was strong support for models incorporating sex as a factor, with the interval growth model reparametrized for capture-mark-recapture data producing later mean maturation estimates than the age-based growth model. We found most individuals (94%) continued growing after maturity, but the instantaneous relative annual plastral growth rate was low. We recommend future studies examine the possible contribution of such slow, continued adult growth to fecundity and survival. Even seemingly negligible amounts of annual adult growth can have demographic consequences affecting the population vital rates for long-lived species.
The Golden Mantella (Mantella aurantiaca) is a highly threatened frog species found in east-central Madagascar. They are seasonally active and difficult to observe outside the summer breeding season. We used a captive population maintained within the native range of the species to examine two aspects of life history that otherwise would be impracticable to observe in the field: sheltering behavior and nearest neighbor distance (NND). We made weekly observations on seven groups of frogs for 1 yr, recording NND of each individual and how many individuals were sheltering under cover. We also recorded whether eggs were present in terraria to better define the breeding season and determine how time of year relates to NND and sheltering behavior. Frogs were closer together and more often took shelter during cool winter months. This corresponds to the time of year when fewer egg clutches were recorded. There was no difference between NND and sheltering behavior in wild-caught vs. captive-bred frogs, and there was no significant difference between NND of males and females. Golden Mantellas may be at increased risk from infectious diseases because behavior that increases contact between infected individuals can facilitate disease transmission.
Turtles and tortoises are among the most threatened vertebrate groups. Their life history is characterized by delayed sexual maturity and a long lifespan, making populations susceptible to decline following perturbations. Despite the urgent conservation need, we are missing estimates of basic demographic traits for many species and populations. The ornate box turtle Terrapene ornata is a species lacking crucial demographic data. Many populations are isolated in fragmented habitats, especially in the eastern portion of their range. We carried out long‐term capture–mark–recapture surveys on two isolated populations in northern Illinois to estimate population vital rates and project population persistence with deterministic stage‐based matrix models. Using 34 years of data, we estimated adult female survival = 0.974 (95% CI: 0.946–0.988) and juvenile survival = 0.867 (95% CI: 0.688–0.951) at our most intensively surveyed site. At a second site using eight years of data, we estimated adult female survival = 0.897 (95% CI: 0.783–0.954) and juvenile survival = 0.844 (95% CI: 0.551–0.960). Despite seemingly high annual survival rates, populations declined under population projections using mean vital rates. Population growth was most sensitive to adult survival, with increasing sensitivity under more pessimistic scenarios. Our results highlight the importance of long‐term demographic studies for threatened species and demonstrate protecting adult female ornate box turtles is critical for ensuring populations persist at the northern edge of their distribution.