Blommersia bara, Vences & Multzsch & Köhler & Crottini & Andreone & Rakotoarison & Scherz & Glaw, 2023

Vences, Miguel, Multzsch, Malte, Köhler, Jörn, Crottini, Angelica, Andreone, Franco, Rakotoarison, Andolalao, Scherz, Mark D. & Glaw, Frank, 2023, Integrative revision of the Blommersia wittei complex, with description of a new species of frog from western and north-western Madagascar, Zootaxa 5319 (2), pp. 178-198 : 192-194

Blommersia bara sp. nov.

Figures 4 , 8

Identity. This species was considered Mantidactylus wittei by Guibé (1974) and Blommers-Schl̂sser & Blanc (1991) for specimens from Ankarafantsika, and called Mantidactylus cf. wittei by Glos (2003), Blommersia sp. aff. wittei “Isalo” by Glaw & Vences (2007), Blommersia sp. aff. wittei by Mercurio et al. (2008), Blommersia sp. ( aff. wittei ) by Bora et al. (2010), Blommersia sp. 5 by Vieites et al. (2009) and Wollenberg et al. (2011), Blommersia sp. Ca5 by Perl et al. (2014), Penny et al. (2016) and Glaw et al. (2019), Blommersia sp. Ca05 by Penny et al. (2017), and Blommersia sp. aff. wittei Ca 05 “Isalo” by Cocca et al. (2018).

Holotype. ZSM 31/2004 (field number FGZC 47), an adult male, collected by F. Glaw, M. Puente, M. Thomas & R. Randrianiaina at a stream near Ranohira, Isalo Massif (22.5856°S, 45.3997°E, 813 a.s.l.), southwestern Madagascar, on 21 January 2004.

Paratypes. A total of 30 specimens, all from western Madagascar. ZSM 22/2004 ( FGZC 34 ) and ZSM 24/2004 ( FGZC 38 ) two adult males with the same collecting data as the holotype ; ZSM 706/2001 ( FGMV 2001.279 ), adult male, collected by M. Vences, D.R. Vieites, G. Garcia, V. Raherisoa, & A. Rasoamamonjinirina at Ampijoroa , Ankarafantsika National Park (approximately 16.3°S, 46.82°E) on 24 February 2001 ; ZSM 246/2003 and ZSM 247/2003, two adult males, collected by J. Glos at Kirindy Forest (site “G2”) in January 2001 ; ZSM 13/2006 ( FGZC 691 ), ZSM 30/2006 ( FGZC 727 ), ZSM 52/2006 ( FGZC 779 ), and ZSM 68/2006 ( FGZC 809 ), two adult females and two adult males, collected by F. Glaw, J. K̂hler, P. Bora & H. Enting at Tsingy de Bemaraha National Park , Andranopasazy, “Camp 1” (18.7086°S, 44.7189°E, 146 m a.s.l.), on 17, 19, and 24 March 2006 , respectively; ZSM 2284/2007 ( ZCMV 5801 ) and ZSM 2285/2007 ( ZCMV 5804 ), one adult male and one adult female, collected by M. Vences and collaborators at Isalo National Park , on 17 February 2007 ; ZSM 2281/2007 ( ZCMV 5625 ), ZSM 2282/2007 ( ZCMV 5626 ), ZSM 2283/2007 ( ZCMV 5643 ), and ZSM 2320/2007 ( ZCMV 5621 ), collected by L. du Preez, C. Weldon & L. Raharivololoniaina at Ankarafantsika , on 9 February 2007 ; ZSM 3222/2012 ( ZCMV 14143 ), adult male collected by A. Rakotoarison, J. Erens & E. Rajeriarison at Mariarano (15.4978°S, 46.6943°E, 11 m a.s.l.), on 28 December 2012 ; MRSN A2957 and A2958 (FAZC 11807–11808), two males, collected by F. Andreone, G. Aprea & V. Mercurio in the Isalo Massif, Andohasahenina (22.8333°S, 45.1880°E, 876 m a.s.l.) on 15 January 2004; MRSN A5349 ( FAZC 12550 ), female, and MRSN A5350 ( FAZC 12551 ), male, collected by F. Andreone, F. Mattioli & V. Mercurio in the Isalo Massif, Zahavola (22.6215°S, 45.3587°E, 881 m a.s.l.), on 17 November 2004 ; MRSN A5353 and A5354 (FAZC 12968 and 12970), two males, collected by F. Andreone, F. Mattioli & V. Mercurio in the Isalo Massif, Sakamalio (22.4348°S, 45.2552°E, 726 m a.s.l.) on 16 December 2004; MRSN A5351 ( FAZC 12591 ), female, collected by F. Andreone, F. Mattioli & V. Mercurio in the Isalo Massif, Andriamanero (22.3672°S, 45.3920°E, 663 m a.s.l.), on 20 November 2004; as well as seven specimens deposited in the UADBA collection (uncatalogued but accessible via field tags): UADBA-ZCMV 5620, 5641, 5642, 5644, four specimens collected by L. du Preez, C. Weldon & L. Raharivololoniaina at Ankarafantsika , on 9 February 2007 ; and UADBA-ZCMV 5800, 5802, 5803, three specimens collected by collected by M. Vences and collaborators at Isalo National Park , on 17 February 2007 .

Diagnosis. A species of the genus Blommersia in the subfamily Mantellinae of the family Mantellidae based on presence of intercalary elements between penultimate and ultimate phalanges of fingers and toes (verified by external examination), occurrence in Madagascar, relatively small body size (male SVL <27 mm), presence of femoral glands in males and absence of femoral gland rudiments in females, head distinctly longer than wide, and molecular phylogenetic relationships.

From other species of Blommersia , the new species is mainly distinguished as follows: from B. angolafa by the presence of vomerine teeth in many individuals (vs. absence) and a totally different color pattern without whitish spots on the flanks and on the finger- and toe-tips (vs. presence); from B. dejongi by a femoral gland placed centrally on the thigh (vs. distally); from B. blommersae by having lateral metatarsalia separated by webbing (vs. connected by dense tissue); from B. domerguei by having lateral metatarsalia separated by webbing (vs. connected by dense tissue), by the presence of vomerine teeth in many individuals (vs. absence), a larger body size (SVL> 20 mm vs. <18 mm), and absence of a distinct pattern with three dark brown bands on a copper-brown dorsum (vs. presence); from B. dupreezi by having lateral metatarsalia separated by webbing (vs. connected by dense tissue) and absence of distinct black lateral stripe (vs. presence); from B. galani by presence of vomerine teeth in many individuals (vs. absence); from B. grandisonae by presence of vomerine teeth in many individuals (vs. absence) and a largely different color pattern (but see discussion in Vences et al. 2023 on the identity of B. grandisonae ); from B. kely by having lateral metatarsalia separated by webbing (vs. connected by dense tissue), presence of vomerine teeth in many individuals (vs. absence), and larger body size (SVL> 20 mm vs. <17 mm); from B. nataliae by ovoid femoral glands in small distance to each other (vs. more rounded, distant glands) and absence of a dark face mask (vs. presence); from B. sarotra by having lateral metatarsalia separated by webbing (vs. connected by dense tissue); from B. transmarina by a narrower head (male HW/SVL ratio 0.29‒0.34 vs. 0.34–0.36) and somewhat shorter hands (male HAL/SVL ratio 0.29–0.33 vs. 0.30–0.35); from B. variabilis by having lateral metatarsalia separated by webbing (vs. connected by dense tissue in most individuals) and probably a smaller distance between femoral gland. Furthermore, differentiated from all these species by differences in advertisement calls and genetic distances>5% in the analyzed mitochondrial 16S rRNA gene fragment of these two species. It differs from B. wittei , however, in a substantial divergence of mitochondrial genes (5.0‒8.2% uncorrected pairwise distance in 16S) and lack of haplotype sharing in RAG1 and SACS, and in advertisement calls lacking distinct pulses vs. being clearly pulsed in B. wittei (except in the Sambava population whose taxonomic status is in need of revision).

Description of the holotype. Adult male specimen with distinct femoral glands, in a good state of preservation ( Fig. 8 ). Tongue removed as tissue samples for molecular analysis. SVL 18.5 mm, for further measurements see Table 1 . Body slender; head longer than wide, of same width as body; snout rounded in lateral view, obtusely pointed in dorsal and ventral views; nostrils directed laterally, protuberant, nearer to snout tip than to eye; canthus rostralis rounded; loreal region slightly concave; tympanum distinct, round, its diameter 63% of eye diameter; supratympanic fold distinct, curved above tympanum where it follows the tympanum outline; tongue absent, its shape therefore not ascertainable; vomerine teeth not visible; choanae small, round, located toward the front of the palate; maxillary teeth present.Arms slender, subarticular tubercles present, single; fingers without webbing; relative length of fingers 1<2<4<3, finger discs enlarged, nuptial pads absent. Hindlimbs slender; tibiotarsal articulation reaches center of eye when the hind limb is adpressed along the body; lateral metatarsalia entirely separated by webbing; comparatively small inner and much smaller outer metatarsal tubercles, which are present but not very distinct; webbing formula 1(traces), 2i(traces), 2e(1), 3i(2.5), 3e(1.75), 4i(2.75), 4e(3), 5(1.75); relative length of toes 1<2<5<3<4. Skin on the upper surface smooth, without folds or ridges. Ventral skin smooth to slightly shagreened. Femoral glands distinct and prominent.

After 19 years in preservative ( Fig. 8 ), the dorsum is rather uniformly brownish, with a weakly recognizable dark brownish inverted chevron, a faint small dark transverse bar on the forehead anterior to the eyes, and a very weakly recognizable dark interorbital bar. A dark stripe runs from the nostril to the eye and continues broader posterior to the eye, encompassing the entire tympanic region underneath the supratympanic fold. Underneath these brown elements, a weakly expressed light frenal stripe is visible from the snout tip to the forelimb insertions. Fore- and hindlimbs dorsally with distinct and sharply delimited brown crossbars (three crossbars on thigh and four on shank). Ventral side uniformly beige (unpigmented), throat being a bit lighter than chest, belly and limbs. In life, color was very similar but somewhat more contrasted ( Fig. 4A ); whitish color was present on the throat; femoral glands granules were somewhat yellowish ( Fig. 4B ).

Variation. ZSM 52/2006 exhibits a broad middorsal light band. Vomerine teeth are clearly visible in paratype ZSM 2281/2007 from Ankarafantsika, also recognizable (although weakly expressed) in the paratypes from Bemaraha. We observed substantial differences in body size among populations, with individuals from the type locality Isalo being distinctly smaller than those from other sites. According to available data (Supplementary Table 2; available at DOI 10.5281/zenodo.8049142) male SVL across all populations ranges between 18.2–25.7 mm and female SVL between 22.0– 26.4 mm.

Etymology. Named after the Bara people, the ethnic group living in the area of Madagascar that includes the type locality of the new species, the Isalo Massif. The name is used as a noun in apposition.

Natural history. A relatively common species in Madagascar, living in areas of a certain humidity such as streams or swamps, including areas of secondary vegetation. During the rainy season, males call during day and night from the low vegetation of these water bodies. In Isalo this species is commonly found on the ground of gallery forests (e.g., Andriamanero, Sakamalio), along temporary rivers and in Pandanus swamps in the open savannah (e.g., Ilakaka, Zahavola). Tadpoles develop in temporary ponds and individuals of this species have been observed in egg-guarding behaviour both in Ankarafantsika ( Fig. 4C ) and Isalo ( Mercurio et al. (2008). In the Sahamalaza Peninsula, this species seems to be abundant and it is found along streams and ponds in intact forested areas as well as in paddy fields in cleared areas. In Bemaraha, specimens were found in the leaf litter. In Kirindy, Glos (2003) found the species in the largest out of 200 ponds studied, and observed males calling at night from a bush at the water edge between 1–4 m above ground.

Vocalizations: Advertisement calls recorded on 29 January 1994 at Isalo (air temperature 21.5°C) consist of a single short pulsatile note repeated in call series at rather regular intervals within series ( Fig. 6 ). Each call exhibits some irregular amplitude modulation, sometimes with 2–4 peaks recognizable within each call, with the second peak usually having the highest energy. Numerical parameters of 23 analyzed calls of one male are as follows: call duration (= note duration) 13–18 ms (15.2 ± 1.6 ms); inter-call intervals within regular call series 69–78 ms (74.8 ± 3.0 ms); duration of regular call series 2034 ms (n = 1); call rate within call series approximately 670 calls/minute; dominant frequency 5813–6115 Hz (5968 ± 119 Hz); second dominant frequency peak around 3000 Hz; prevalent bandwidth 2600–9500 Hz.

Advertisement calls recorded on 24 February 2001 at Ankarafantsika (air temperature 28°C) consist of a single short pulsatile note repeated in call series at regular intervals within series ( Fig. 6 ). In some calls (= notes) two barely separated peaks of amplitude are recognizable, but call energy is distributed rather equally along the first two thirds of the call’s duration, then dropping rapidly towards its end. Numerical parameters of 18 analyzed calls of one male are as follows: call duration (= note duration) 19–28 ms (23.2 ± 2.5 ms); inter-call intervals within regular call series 94–107 ms (97.3 ± 4.8 ms); duration of regular call series 2078 ms (n = 1); call rate within call series approximately 500 calls/minute; dominant frequency 4694–4758 Hz (4735 ± 27 Hz); second frequency peak around 2370 Hz; prevalent bandwidth 1900–9700 Hz.

Distribution. Known from Isalo in the South-West up to Sahamalaza Peninsula in the North-West (see Fig. 2 for genetically confirmed sites). The precise contact zone with B. wittei has not yet been identified but can be expected to be located between Sahamalaza and Ambanja.

Figures

FIGURE 2. Map of Madagascar showing the distribution records of the Blommersia wittei species complex. Only locations confirmed by molecular data are shown.

FIGURE 4. Blommersia bara sp. nov. (= B. sp. Ca5) in life. (A,B): Male holotype ZSM 31/2004 (FGZC 47) from Isalo in dorsolateral and ventral view. (C) Individual from Ankarafantsika displaying egg-guarding behavior. (D) Female paratype ZSM 13/2006 from Tsingy de Bemaraha. (E) Additional individual (not clearly referable to a voucher) from Tsingy de Bemaraha.

FIGURE 6. Audiospectrograms and corresponding oscillograms of advertisement calls of Blommersia bara sp. nov. (= B. sp. Ca5) from two different localities (each showing several calls of a call series).

FIGURE 8. Preserved name-bearing type specimens of Blommersia wittei and Blommersia bara sp. nov. in dorsal and ventral views. Photographs of the B. wittei holotype by RECOLNAT (ANR-11-INBS-0004) / Antoine Fraysse, available from https:// science.mnhn.fr/institution/mnhn/collection/ra/item/1953.60.