Boophis siskoi, Vences & Köhler & Hutter & Preick & Petzold & Rakotoarison & Ratsoavina & Glaw & Scherz, 2024

Vences, Miguel, Köhler, Jörn, Hutter, Carl R., Preick, Michaela, Petzold, Alice, Rakotoarison, Andolalao, Ratsoavina, Fanomezana M., Glaw, Frank & Scherz, Mark D., 2024, Communicator whistles: A Trek through the taxonomy of the Boophis marojezensis complex reveals seven new, morphologically cryptic treefrogs from Madagascar (Amphibia: Anura: Mantellidae), Vertebrate Zoology 74, pp. 643-681 : 643-681

Boophis siskoi sp. nov.

Lineage G Figures 6 , 11

Identity.

This species has been previously referred to as B. marojezensis [Ca 52 JQ 518215 ] = B. marojezensis [Ca 52] in Randrianiaina et al. (2012), and B. sp. Ca 52 in Perl et al. (2014) and Hutter et al. (2018). It was included in B. marojezensis sensu lato in Glaw and Vences (2007) and not explicitly included or mentioned by Glaw et al. (2001) and Vieites et al. (2009).

Holotype.

ZSM 614 / 2001 (FGMV 2001.64), adult male (call voucher) collected by F. Andreone, F. Mattioli, J. Randrianirina, and M. Vences on 3 February 2001 at Antsahamanara campsite , Manarikoba forest, Tsaratanana Massif (14.045 ° S, 48.784 ° E, ca. 1000 m a. s. l.), Sambirano region, Madagascar.

Paratypes.

ZSM 615 / 2001 (FGMV 2001.71) and ZSM 616 / 2001 (FGMV 2001.80), two adult males with same collecting data as holotype but collected 4‒9 February 2001 ( ZSM 615 / 2001 not DNA barcoded) . ZSM 10 / 2016 (MSZC 186), adult male, collected by M. D. Scherz, J. Borrell, L. Ball, T. Starnes, E. Razafimandimby, D. H. Nomenjanahary, and J. Rabearivony on 9 January 2016 at Ampotsidy , 15.7 km NNW of Bealanana (8.7 km NNW of Beandrarezona; 14.4276 ° S, 48.7223 ° E, 1320 m a. s. l.) .

Definition.

A small treefrog assigned to the genus Boophis , subgenus Boophis , in the family Mantellidae based on occurrence on Madagascar, presence of intercalary element between ultimate and penultimate phalanx of fingers and toes (verified by external examination), presence of webbing between fingers, presence of nuptial pads in males, and absence of femoral glands in males. Assigned to the Boophis blommersae group based on small body size (male SVL 25.0– 27.2 mm), predominantly brownish dorsal coloration, absence of red color on webbing or ventral side of limbs, suctorial stream-dwelling tadpoles, and molecular phylogenetic relationships. Within the B. blommersae group, defined by absence of dorsolateral bands, absence of red color in outer iris area, and advertisement calls with dominant frequencies of 4688–5332 Hz, consisting of 7–12 whistling notes of 44–220 ms duration, each with constant upward frequency modulation. Also characterized by numerous diagnostic nucleotide positions in the mitochondrial 16 S rRNA gene: MolD identified the following robust diagnostic nucleotide combination compared to all other species in the B. marojezensis complex (sites given relative to the full-length 16 S sequence of Mantella baroni ): “ G ” in the site 109, “ T ” in the site 163, “ A ” in the site 233.

Diagnosis.

Within the B. blommersae group, distinguished from B. blommersae by calls consisting of a series of whistles (vs. pulsed trills); and from B. vittatus by calls consisting of a series of whistles (vs. series of short clicks), and absence of dorsolateral stripes (vs. presence). Furthermore, distinguished from B. marojezensis by somewhat larger body size (male SVL 25.0–27.2 vs. 20.0– 25.7 mm), advertisement calls consisting of notes of rather similar duration (vs. clear distinction of short and long notes); from B. kirki sp. nov. by larger body size (male SVL 25.0–27.2 vs. 20.0– 23.4 mm), advertisement calls with notes of maximum duration of 220 ms (vs. max. duration of 105 ms) and with regularly ascending frequency modulation (vs. very steep initial frequency ascent in the beginning of each note, slowing down towards end of note), and absence of red color in outer iris area (vs. presence in some specimens); from B. picardi sp. nov. by larger body size (male SVL 25.0–27.2 vs. 21.3–23.2 mm), advertisement calls consisting of notes of rather similar duration (vs. clear distinction of short and long notes), and absence of red color in outer iris area (vs. distinct in many specimens); and from B. pikei sp. nov. by larger body size (male SVL 25.0–27.2 vs. 21.4–25.0 mm), and advertisement calls consisting of 7–12 notes (vs. 25–33 notes) of maximum duration of 220 ms (vs. max. duration of 98 ms). For a distinction from other species of the B. marojezensis complex described herein, see accounts of these new species below.

Description of the holotype.

Adult male, in excellent state of preservation, SVL 25.8 mm, muscle tissue removed from left thigh for molecular analysis. Body moderately slender; head slightly wider than long and slightly wider than body; snout rounded to truncate in dorsal view, moderately rounded to sloping in lateral view; nostrils directed laterally, nearer to tip of snout than to eye; canthus rostralis rather weakly expressed, concave in dorsal view, loreal region slightly concave; tympanum rather distinct, round, TD 39 % of ED; supratympanic fold distinct, slightly curved in its anterior and straight in its posterior half; vomerine odontophores weakly developed, well-separated in two very small rounded aggregations, positioned posteromedial to choanae; choanae small to medium-sized, rounded; maxillary teeth present. Tongue ovoid, posteriorly bifid, free. Arms slender, forearms of slightly larger diameter, subarticular tubercles single, round; metacarpal tubercles not recognizable; fingers weakly webbed and with lateral dermal fringes; webbing formula 1 (traces), 2 i (traces), 2 e (traces), 3 i (traces), 3 e (2), 4 (1); relative length of fingers 1 <2 <4 <3 (finger 2 distinctly shorter than finger 4); finger discs enlarged, rounded; nuptial pads recognizable as unpigmented swelling on first finger. Hindlimbs slender; tibiotarsal articulation reaching beyond tip of snout when hindlimb is adpressed along body; lateral metatarsalia separated by webbing; inner metatarsal tubercle small, distinct, elongated; no outer metatarsal tubercle; toes broadly webbed; webbing formula 1 (0.5), 2 i (0.75), 2 e (0.5), 3 i (1.25), 3 e (0.5), 4 i (2), 4 e (2), 5 (0.5); relative length of toes 1 <2 <3 <5 <4; toe discs enlarged, rounded. Skin smooth on dorsal surfaces, throat, chest, and ventral surface of thighs, finely granular on belly; cloacal region surrounded by an area of distinct, large, white-colored granules.

In preservative, 22 years after collection (Fig. 6 ), dorsally red brown with a distinct and moderately contrasted dark brown hourglass marking on anterior part of the dorsum, and a dark brown curved transverse bar on the posterior part of the dorsum. A narrow dark transverse bar is visible between the eyes. Dorsum with many poorly delimited and indistinct small dark spots. Limbs light brown with distinct darker brown crossbands: about 3 on forearm, 3–5 on shank, 5 on thigh. Ventrally cream, white on belly and with dark pigment on ventral side of feet. In life (Fig. 11 ), similar but dorsal color light brown rather than reddish brown. Outer iris color yellowish, inner iris color light brown, iris periphery turquoise.

Variation.

All paratypes in preservative have the typical pattern of a dark hourglass-patch on the anterior and a transverse bar or inverted U-patch on the posterior dorsum. ZSM 616 / 2001 has a small pink dot on the central dorsum. In life, the dark dorsal markings are sometimes poorly contrasted (Fig. 11 A ).

Etymology.

Named after the fictional character Captain Benjamin Sisko, first portrayed by Avery Brooks in Rick Berman and Michael Piller’s Star Trek: Deep Space Nine.

Tadpole.

The tadpole of this species (under the name B. marojezensis [Ca 52]) was described and illustrated by Randrianiaina et al. (2012), based on the DNA barcoded specimen ZSM 541 / 2010 (ZCMV 13168; GenBank accession number JQ 518215 ) from Ambinanitelo. As typical for all tadpoles of the group, the larvae belong to the “ suctorial ” ecomorphological guild. They have a large oral disk used to adhere to stones in fast-flowing water, a labial tooth row formula of 7 (5-7) / 3, and large numbers of oral papillae (258 marginal and 522 submarginal; without dorsal gap). They are characterized by presence of a (poorly recognizable) lateral transparent area of the integument, and absence of dark (melanophoric) pigment on the tail.

Natural history.

An arboreal, nocturnal treefrog found in humid rainforests along fast flowing streams. Little is known of the ecology of the species. At Ampotsidy, this species was only encountered along a large river, and was not heard along narrower streams at higher elevations.

Calls.

Advertisement calls of B. siskoi sp. nov. recorded at the type locality, Antsahamanara, Tsaratanana massif, on 3 February 2001 (24 ° C air temperature) consist of multiple notes (almost tonal in character, but with some irregular amplitude modulation) of variable duration, repeated at variable intervals. Within calls, note duration and inter-note intervals become longer from the beginning to the end of the call. Each note exhibits upward frequency modulation, which is most expressed in the last note (comprising a frequency shift of about 300 Hz) and much less in the first notes of the call. Overall frequency of the call exhibits a slight drop from the beginning to the end of about 200 Hz from the first notes compared to the last note (Fig. 5 ). However, in some calls the first 2–3 notes exhibit a lower frequency than subsequent ones. Each note is amplitude modulated with maximum call energy usually present somewhere in the first half of the note’s duration. Numerical parameters of four analyzed calls are as follows: call duration 1549–2168 ms (1877.0 ± 311.2 ms); notes / call 10–12 (10.7 ± 1.2); note duration 44–220 ms (89.8 ± 44.5 ms); inter-note interval 41–162 ms (72.6 ± 31.7 ms); dominant frequency 4890–5332 Hz (5125 ± 222 Hz); prevalent bandwidth 4000–5600 Hz.

A call of B. siskoi sp. nov. recorded at Ampotsidy, on 13 January 2016 at 18: 43 (air temperature not recorded), differs from the calls described from Tsaratanana by less variation in note duration and lack of a distinct overall frequency drop from the beginning to the end of the call (Fig. 5 ). Numerical parameters of this analyzed call are as follows: call duration 1805 ms; notes / call 7; note duration 114–165 ms (144.3 ± 18.5 ms); inter-note interval 88–180 ms (125.7 ± 30.8 ms); dominant frequency 4688 Hz; prevalent bandwidth 3800–5200 Hz.

Distribution.

According to molecular data summarized herein, the species is known from (1) the type locality, Antsahamanara campsite on the western versant of the Tsaratanana Massif, (2) Ambinanitelo forest (14.2254 ° S, 48.9635 ° E, 1182 m a. s. l.; Randrianiaina et al. 2012), and (3) Ampotsidy forest. The elevational range of the species spans between ca. 1000–1320 m a. s. l.

Figures

Figure 5. Comparative spectrograms and oscillograms illustrating representative calls of various species in the Boophis marojezensis complex, all at 4000 ms time scale.

Figure 6. Preserved holotypes in dorsal and ventral views of the eight nominal species in the Boophis marojezensis complex described in this study.

Figure 11. Individuals (adult males) of Boophis siskoi sp. nov. in life. A paratype ZSM 10 / 2016 (MSZC 186) from Ampotsidy. B holotype ZSM 614 / 2001 (FGMV 2001.64) from the Tsaratanana Massif (Antsahamanara campsite).