Contributions to Zoology, 86 (4) – 2017Samuel G. Penny; Angelica Crottini; Franco Andreone; Adriana Bellati; Lovasoa M.S. Rakotozafy; Marc W. Holderied; Christoph Schwitzer; Gonçalo M. Rosa: Combining old and new evidence to increase the known biodiversity value of the Sahamalaza Peninsula, Northwest Madagascar

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Results

This survey increases the total number of amphibian and reptile species known from the Sahamalaza Peninsula to 20 and 43 respectively (Table 2). A total of 17 amphibian species and 38 reptile species were found during the current survey period; all were encountered during either opportunistic or transect searching, 14 of the amphibian species were also detected through automated acoustic recording (40122 minutes analysed) and one species of amphibian and three of reptile during pitfall trapping (840 pitfall trap days which yielded a capture rate of 1.12%). Survey effort amounts to 84 days in Ankarafa and 16 days in Anabohazo, or 28 days if survey effort by Andreone et al. (2001) is included. The cumulative number of species detected rose quickly during the start of the survey period and then began to stabilise, with almost 82% of the species being found in the first 50 days of survey (Figure 2). After reaching a plateau, we observed again the discovery of new species during the last 13 days (Figure 2). This overall pattern is observed on both groups of species.

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Table 2. Distribution of amphibian and reptile species of the Sahamalaza Peninsula. The survey at Analavory Forest was conducted by Raselimanana (2008), while previous surveys at Anabohazo Forest and Betsimipoaka village were conducted by Andreone et al. (2001). The most recent survey conducted in 2011-13 revisited Anabohazo Forest and Betsimipoaka village, and also surveyed Ankarafa Forest and Antafiabe village and its surroundings. * species ID limited to photographic record. † species ID limited to observation only. CCS: confirmed candidate species, UCS: unconfirmed candidate species, DCL: deep conspecific lineage (according to Vieites et al., 2009).

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Figure 2. Species accumulation curves (based on all sampling techniques) for amphibian and reptiles species in Sahamalaza Peninsula. Curves show the accumulation during the full duration of the project, covering the wet season.

Six species of amphibians (Figure 3) and eleven reptiles (Figure 4) were documented for the first time from Sahamalaza (Table 2), with two of these taxa qualifying as new candidate species. These are Boophis ankarafensis, already described previously as a direct result of this survey (Penny et al., 2014) and Stumpffia sp. aff. pygmaea Ca “Sahamalaza” (UCS) (Table 2 and S1).

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Figure 3. Amphibian species documented for the first time from the Sahamalaza Peninsula during the survey period 2011-2013: A. Heterixalus tricolor from Ankarafa Forest; B. Boophis brachychir from Ankarafa Forest; C. Boophis ankarafensis recently described from Ankarafa Forest; D. Blommersia sp. Ca05 (UCS), a candidate species reported from Ankarafa Forest; E. Stumpffia sp. aff. pygmaea Ca “Sahamalaza” (UCS), a candidate species reported from Ankarafa Forest; F. Hoplobatrachus tigerinus from Anketsakely. Photo A by S. Penny, B-F by G. M. Rosa.

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Figure 4. Reptile species documented for the first time from the Sahamalaza Peninsula during the survey period 2011-2013: A. Acrantophis madagascariensis from Berara Forest; B. Ithycyphus perineti from Ankarafa Forest; C. Dromicodryas bernieri from Ankarafa Forest; D. Ebenavia inunguis from Ankarafa Forest; E. Phelsuma sp. aff. quadriocellata from Ankarafa Forest; F. Phelsuma vanheygeni from Ankarafa Forest; G. Phelsuma laticauda from Ankarafa Forest; H. Geckolepis humbolti from Anketsakely; I. Brookesia minima from Ankarafa Forest; J. Pelomedusa subrufa from Betsimipoaka. Photos A-C, E-F by S. Penny, and D, G-J by G. M. Rosa.

Seven taxa are so far known exclusively from the peninsula: Boophis ankarafensis, Boophis tsilomaro, Cophyla berara, Platypelis sp., Rhombophryne sp., Stumpffia sp. aff. pygmaea Ca “Sahamalaza” and Pseudoacontias menamainty; although also Lygodactylus tolampyae show a distinct genetic distance from the other known localitity from where genetic data are available (12% uncorrected pairwise genetic distance at 16S fragment between the population from Sahamalaza and Ankarafantsika) and future taxonomic revisions of this genus might confirm this record as a further candidate new species. There were several species previously recorded from Sahamalaza that were not detected during this last survey: three amphibians (Laliostoma labrosum, Platypelis sp. and Rhombophryne sp.) and five reptiles (Alluaudina bellyi, Ithycyphus miniatus, Paracontias hildebrandti, Pseudoacontias menamainty and Sanzinia madagascariensis) (see Table 2).

Nine of the species in our survey are treated as synonymous with those identified by Andreone et al. (2001), these are: Boophis tsilomaro (with Boophis albilabris), Cophyla berara (with Cophyla sp. 12), Stumpffia gimmeli (with Stumpffia cf. gimmeli), Flexiseps tanysoma (with Amphiglossus sp.), Phelsuma kochi (with Phelsuma madagascariensis), Pseudoacontias menamainty (with Pseudoacontias n. sp.), Blaesodactylus ambonihazo (with Blaesodactylus sakalava), Hemidactylus mercatorius (with H. cf. frenatus) and Lycodryas granuliceps (with L. pseudogranuliceps).