The amphibians and reptiles of Nosy Be (NW Madagascar) and nearby islands: a case study of diversity and conservation of an insular fauna

Surveys of the amphibians and reptiles on Nosy Be (an island off north-west Madagascar) and nearby islands were undertaken between 1991 and 2001 and are discussed here in view of biodiversity considerations and conservation efforts. Since Nosy Be is the type locality of several amphibian and reptile taxa, their exact status is of crucial importance for the nomenclatural stability of many groups of the Madagascan herpetofauna. A total of 20 amphibian and 61 reptile species (excluding marine reptiles) was confirmed for this archipelago. Other species (Mantidactylus horridus, Androngo elongatus, Typhlops madagascariensis, T. reuteri, Micropisthodon ochraceus and Pararhadinea melanogaster) were not found during these inventories, but are quoted in the literature or housed in herpetological collections, and are considered as likely to be present at Nosy Be. A further 18 taxa are tentatively excluded from its fauna, due to biogeographic incongruence and/or lack of reliable voucher specimens. Few taxa are so far only known from the island; they may represent endemics or may have been overlooked on the adjacent mainland. They are respectively Stumpffia pygmaea, Mabuya lavarambo, Lygodactylus h. heterurus, Lycodryas granuliceps and Typhlops reuteri. Heterixalus tricolor too is likely to be present on Nosy Be only, but the difference with respect to taxa present on the mainland needs to be confirmed. Several species are known from nearby islands and islets surveyed (11 amphibians and 26 reptiles). A few of them (Heterixalus 'variabilis', Kinixys belliana, Furcifer oustaleti, Mabuya comorensis, Paracontias milloti) are present on some of these islands but have not yet been found on Nosy Be. Much of the field research was conducted at Lokobe, a strict nature reserve still characterized by good forest coverage (typical of the Sambirano Domain), and an important area of biodiversity. With 15 amphibian and 45 reptile species, Lokobe hosts 81% of the overall Nosy Be herpetofauna: of the species found during our surveys, only Heterixalus tricolor, Hoplobatrachus tigerinus, Gehyra mutilata, Phelsuma dubia and Crocodylus niloticus were only found outside the reserve. In view of this, the protection of Lokobe should be assured and reinforced. Except for Lokobe, habitats on Nosy Be are largely anthropogenic, and have a lower species diversity, especially where there is intensive agriculture. At other sites (e.g. ylang-ylang and coffee plantations) and in forested bands along roads, species diversity is still high: careful management of these anthropogenic habitats might also assure the survivorship and conservation of a diverse herpetofauna outside the protected area.     

Geckos are milking honeydew-producing planthoppers in Madagascar

In this paper we describe for the first time an extraordinary example of an interspecific trophobiotic relation between reptiles and planthoppers in Madagascar. Day gecko species of the genera Phelsuma and Lygodactylus as well as the nocturnal gecko Homopholis sakalava (Grandidier, 1867) show a particular behaviour that induces planthoppers of the family Flatidae to excrete a drop of honeydew in the course of an interspecific key stimulus reaction. Similar behaviour patterns are well known between ants and green flies or planthoppers, but have not been reported for vertebrates.     

Herpetological diversity across intact and modified habitats of Nosy Komba Island,Madagascar

A six month herpetological survey was undertaken between March and September 2015 on Nosy Komba, an island off of the north-west coast of mainland Madagascar which has undergone considerable anthropogenic modification. A total of 14 species were found that have not been previously recorded on Nosy Komba, bringing the total island diversity to 52 (41 reptiles and 11 frogs). The species assemblage, richness and abundance of four distinct habitat types were compared: closed-canopy forest, disturbed-canopy forest, shade-grown coffee plantation and mixed open plantation. The anthropogenic habitats on Nosy Komba were found to be of high conservation value for reptile species, where species richness and abundance found during surveys was equal to or higher than closed-canopy forest. By contrast, the abundance and species richness for frogs was reduced in anthropogenic habitats, especially in sun-exposed plantations. The forested areas of Nosy Komba contain twelve IUCN threatened species (9 reptiles and 3 frogs). Of these, Uroplatus henkeli, Uroplatus ebenaui, Phelsuma seippi, Zonosaurus subuniclor, Stumpffia psologlossa and Stumpffia pygmaea were also found in shade-grown coffee plantations, demonstrating the conservation value of these anthropogenic environments. Five threatened species on Nosy Komba were found exclusively in forested areas: Brookesia minima, Brookesia ebenaui, Lygodactylus madagascariensis, Rhombophryne testudo and Thamnosophis stumpffi. Our surveys demonstrate the importance of Nosy Komba for conserving regionally endemic and threatened species, and the often under-appreciated value of anthropogenic environments in species conservation, when also coupled with the protection of primary forest.     

Mungotictis decemlineata lineata (Carnivora: Herpestidae), a mysterious Malagasy mongoose

The Malagasy narrow-striped mongoose Mungotictis decemlineata has two currently recognized subspecies: M. d. decemlineata and M. d. lineata. Recent literature indicates that the latter is very rare, occurring in the Toliara region of southwestern Madagascar, however there are no original locality data available for the sole specimen of this taxon, and there is no evidence to suggest that it occurs anywhere near Toliara. Fieldwork to find it should be targeted initially in the Kirindy-Sud/Marofihitse region south of Morondava, central western Madagascar.     

Revision of the Madagascan genus Madecorphnus Paulian (Coleoptera: Scarabaeidae: Orphninae)

A scarab beetle genus, Madecorphnus Paulian, endemic to Madagascar, is revised. Nine new species are described: M. brunneus sp. nov., M. dentatus sp. nov., M. montreuili sp. nov., M. niger sp. nov., M. pauliani sp. nov., M. perinetensis sp. nov., M. peyrierasi sp. nov., M. punctatus sp. nov., M. simplex sp. nov. Diagnosis of the genus is clarified. Distribution map and a diagnostic key to all species are presented.     

Sogalabana ochracea gen. et sp. nov. from Tsaratanana massif in northern Madagascar (Hemiptera: Fulgoromorpha: Flatidae)

The paper describes a new flatid genus, Sogalabana gen. nov., and a new species Sogalabana ochracea sp. nov. from Madagascar. Illustrations of the female internal genital structures are provided.

htpp://zoobank.org/urn:lsid:zoobank.org:act:CF80D959-FB22-4EDB-A2BA-A1628ABF9C15     

Elevational zonation of birds,insectivores, rodents and primates on the slopes of the Andringitra Massif,Madagascar

A review is presented of the birds, lipotyphlans, rodents and lemurs occurring across an elevational transect from 720 to 2450 m within the 31160ha Parc National (PN) d'Andringitra in south-central Madagascar. The broad range of habitats within this reserve consists of lowland forest, montane forest, sclerophyllous forest, montane thicket, to open areas of bare rocks covered by geophytes. Eight different zones were surveyed across this elevational range for most of these four vertebrate orders. On the basis of these surveys and other sources of information, 106 species of birds, 16 species of Lipotyphla, 11 species of rodents (including two introduced species) and 13 species of primates are documented within the reserve. Surveys of the carnivores are incomplete, although eight species, three of which are introduced, have been recorded in the reserve. Forty-eight species of non-volant mammals are known from the Andringitra Massif, 43 of which are endemic to Madagascar. The highest species richness for birds was 85 species in the disturbed lowland forest at 720m zone and there was a subsequent reduction in the number of species at each site with increasing elevation. The two zones at 1210 and 1625 m with montane and mixed montane/sclerophyllous forest had the greatest species richness of non-volant mammals with 26 species (25 non-introduced). Lemurs showed decreasing species richness with increasing elevation. Small mammals showed broad elevational ranges and high species diversity in the middle to upper portion of the forest zone, with lipotyphlans peaking at 1990 m and rodents between 1625 and 1960 m. About 88 species of extant native rodents, carnivores, lipotyphlans and primates are currently recognized to occur on Madagascar. Thus, the PN d'Andringitra holds nearly 50% of the total known fauna of these groups from the island. This relatively small reserve plays a major role in safe-guarding a large proportion of the non-volant mammal fauna of Madagascar.     

Target-enriched DNA sequencing from historical type material enables a partial revision of the Madagascar giant stream frogs (genus Mantidactylus)

ABSTRACT

The subgenus Mantidactylus is a group of frogs endemic to Madagascar, including the largest anuran species on the island. Although these frogs are common and widely distributed, their taxonomy remains unclear. Two species are currently recognised, M. grandidieri and M. guttulatus, with another available name, Rana pigra, considered to be a synonym of M. grandidieri. However, molecular studies have suggested the presence of several cryptic species within the group. Additionally, due to the lack of prominent morphological features, allocating the available names to evolutionary lineages has proven challenging. In the present study, we take a first step towards solving these problems by using fragments of the 16S mitochondrial gene and RAG1 nuclear gene from all over the range of the subgenus to describe its genetic diversity. We also use a newly designed target enrichment laboratory protocol to sequence three mitochondrial fragments from five name-holding museum specimens (as old as 120 years) in order to determine to which lineages the existing names should be applied. The study of the 16S mitochondrial gene revealed 7 geographically separated lineages, distinct enough to be considered candidate species. Out of the five museum specimens analysed, four successfully yielded DNA sequences and could be attributed to one of the aforementioned lineages. Therefore, the name Mantidactylus grandidieri should be applied to the populations from North-Eastern Madagascar, while M. guttulatus refers to populations from inland localities along the Eastern coast of the island. On the other hand, the holotype of Rana pigra did not yield enough genetic material to allow definitive identification. While our data were not sufficient to assess the status of the four lineages distributed along the Eastern coast, the populations from North-Western Madagascar were highly distinct on both the mitochondrial and nuclear markers. We thus describe them as a new species, M. radaka sp. nov.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:1EDDAF0D-FE37-490A-B09E-E136A0C5CB35     

Mixed‐species social aggregations in Madagascan tadpoles—determinants and species composition

The frequency, species composition, and determinants of mixed‐species tadpole aggregations were analysed under natural conditions in a dry forest of western Madagascar. Most aggregations (73%) were formed by more than one species, with up to four species per individual aggregation. Dyscophus insularis (Microhylidae) and Aglyptodactylus securifer (Mantellidae) were the most abundant species in these aggregations. Using a logistic regression model we analysed to what extent the presence and absence of aggregations in a pond can be predicted by its biotic and abiotic habitat variables. Aggregations are more likely in deep, clear ponds with little leaf litter cover on the bottom, while the overall density of invertebrate predators in the pond seems to play a minor role. Our observations suggest that the formation of mixed‐species aggregations in tadpoles of the Kirindy Forest in our system is primarily a reaction to vertebrate predators. Therefore, aggregation behaviour may play a key role in the ability of several anuran species to utilize these spawning waters that are unpredictable in regard to the presence of fish and other vertebrates.     

A new species of Mantidactylus (subgenus Guibemantis) from Madagascar,with a comparative survey of internal femoral gland structure in the genus (Amphibia: Ranidae: Mantellinae)

A new species of Mantidactylus (subgenus Guibemantis) from the rainforests of eastern Madagascar is described. The new species is sympatric with the closely related M. depressiceps (Boulenger, 1882) and M. tornieri (Ahl, 1929) but differs by larger size, a more strongly developed prepollex, and by advertisement calls. Mantidactylus acuticeps Ahl, 1929 and Rhacophorus mocquardii Boulenger, 1896 are confirmed to be junior synonyms of M. depressiceps. The presence of distinct femoral glands in the new species was noted; a feature so far not reliably recognized in other members of the subgenus Guibemantis. Femoral gland structure was investigated in representatives of each of the subgenera included in Mantidactylus by dissecting and reflecting the femoral skin. Four femoral gland types were identified. Type 1: many small, single granules in an ill-delimited patch, grouped in rosettes at the patch edges; type 2: a group of moderately sized granules in a well-delimited patch; type 3: comprising two different structures: distal granules enclosing externally a distinct central depression, and smaller proximal granules or groups of granules; type 4: as type 3, but lacking the proximal granules. Mantidactylus rivicola Vences, Glaw and Andreone, 1997, M. cf. malagasius (Methuen and Hewitt, 1913) and M. ventrimaculatus (Angel, 1935) differed from all other species examined; their femoral glands comprise a reduced number of large granules with an indistinct central depression in external view. The presence of a distal granule group with external central depression (types 3 and 4 above) provides a probable synapomorphy for the subgenera Brygoomantis, Ochthomantis, Hylobatrachus, Chonomantis and Mantidactylus. In females of these subgenera rudimentary femoral glands are present, but they lack completely in females of the other groups.