Boophis archeri, 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 archeri sp. nov.

Lineage E Figures 6 , 13

Identity.

This species has been newly discovered in this study and has not been included in any of the previous studies including B. marojezensis and allied candidate species (e. g., Glaw et al. 2001; Glaw and Vences 2007; Vieites et al. 2009; Randrianiaina et al. 2012; Perl et al. 2014; Hutter et al. 2018).

Holotype.

ZSM 12 / 2016 (MSZC 213), adult male, collected by M. D. Scherz and M. Rakotondratisma on 15 January 2016 at Bevitagnono forest , 33.1 km SW of Bealanana on the road RN 31 (14.7387 ° S, 48.5170 ° E, 1016 m a. s. l.), North West of Madagascar.

Paratypes.

ZSM 11 / 2016 (MSZC 198), adult male, collected by M. D. Scherz and M. Rakotondratsima on 14 January 2016 at Andranonafindra forest , 30 km SW of Bealanana on the road RN 31 (14.7360 ° S, 48.5481 ° E, 1169 m a. s. l.) ; ZSM 13 / 2016 (MSZC 243), adult female, collected by M. D. Scherz and M. Rakotondratsima on 17 January 2016 at Andranonafindra forest , 30 km SW of Bealanana on the road RN 31 (14.7360 ° S, 48.5489 ° E, 1138 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– 25.3 mm), predominantly brownish dorsal coloration, absence of red color on webbing or ventral side of limbs, males calling along streams, 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 4130–4799 Hz, consisting of a series of 3–6 whistling notes of 158–308 ms duration and strong frequency modulation (frequency ascending and then descending in each note). 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 ): “ D ” in the site 253, “ T ” in the site 277, “ A ” in the site 303.

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 advertisement calls consisting of notes of rather similar duration (vs. clear distinction of short and long notes), and minimum note duration of 158 ms (vs. 15 ms); from B. kirki sp. nov. by advertisement calls consisting of 3–6 notes (vs. 9–19 notes) and longer note duration (158–308 ms vs. 54–105 ms), and absence of red color in outer iris area (vs. presence in some specimens); from B. picardi sp. nov. by advertisement calls consisting of notes of rather similar duration (vs. clear distinction of short and long notes), consisting of 3–6 notes (vs. 17–25 notes), minimum note duration 158 ms (vs. 19 ms), and absence of red color in outer iris area (vs. distinct in many specimens); from B. pikei sp. nov. by advertisement calls consisting of 3–6 notes (vs. 25–33 notes) of 158–308 ms note duration (vs. max. duration of 98 ms); from B. siskoi sp. nov. by advertisement calls consisting of 3–6 notes (vs. 7–12 notes), with each note strongly frequency-modulated with an initial ascent and final descent of frequency (vs. regularly ascending frequency); and from B. janewayae sp. nov. by advertisement calls with each note strongly frequency-modulated with an initial ascent and final descent of frequency (vs. regularly ascending frequency), and higher dominant frequency (4130–4799 vs. 2687–3404 Hz). 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 25.3 mm, muscle tissue removed from left thigh for molecular analysis. Body moderately slender; head slightly wider than long, as wide as body; snout rounded in dorsal view, sloped to rounded in lateral view; nostrils directed laterally, nearer to eye than to tip of snout; canthus rostralis indistinct, slightly concave in dorsal view, loreal region slightly concave; tympanum very indistinct, estimated TD about 43 % of ED; supratympanic fold poorly recognizable, slightly curved in its anterior and more straight in its posterior half; vomerine odontophores weakly developed, well-separated in two small rounded aggregations, positioned posteromedial to choanae; choanae medium-sized, rounded to ovoid; 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 (1.5); 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 anterior edge of eye 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 (0.25), 2 i (0.75), 2 e (0), 3 i (1.25), 3 e (0), 4 i (1.75), 4 e (1.75), 5 (0.25); 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, 7 years after collection (Fig. 6 ), dorsally light reddish brown with a moderately contrasted but incomplete and somewhat discontinuous brown hourglass marking on anterior part of the dorsum, a broad brown transverse bar on the posterior part of the dorsum, and a narrow dark transverse bar between the eyes. Dorsum densely spotted with poorly contrasted small brown spots. Limbs light brown with darker brown crossbands: about 4 poorly marked crossbands on forearm, 5 on shank, 7–8 on thigh. Ventrally cream, white on belly and with dark pigment on ventral side of feet. In life (Fig. 13 ), dorsally cream and all dark dorsal elements poorly contrasted. Iris rather uniformly beige, iris periphery turquoise.

Variation.

The female ZSM 13 / 2016 in preservative has a pattern of fine blackish spots across the dorsum, in addition to a moderately contrasted hourglass-patch on the anterior dorsum and second dark patch on the posterior dorsum. In life, the female had a more reddish brown dorsal color, and reddish brown color also in the iris; it contains a large number of mature oocytes, recognizable without dissection.

Etymology.

Named after the fictional character Captain Jonathan Archer, first portrayed by Scott Bakula in Rick Berman and Brannon Braga’s Star Trek: Enterprise.

Tadpole.

The tadpole of this species is unknown.

Natural history.

An arboreal, nocturnal treefrog found in humid rainforests. Little is known of the ecology of the species. At the type locality, there was a remarkable density of these frogs in diminutive riparian forest fragments. Males frequently emitted calls whilst moving among the narrow twigs overhanging the stream.

Calls.

Advertisement calls of B. archeri sp. nov., recorded at Bevitagnono and Andranonafindra forests from the holotype and the male paratype on 14–15 January 2016 (air temperature not recorded), consist of multiple tonal notes, sounding like whistles. Within calls, inter-note intervals become longer from the beginning to the end of the call. All notes exhibit a distinct upward frequency modulation, with a frequency shift comprising approximately 400 Hz. The first note of each call is lower in relative amplitude when compared to subsequent notes. Amplitude modulation within notes is only slightly expressed (most distinct in first note), with increasing amplitude reaching its maximum at the second half of the note’s duration. Numerical parameters of nine analyzed calls of three different individuals (among them call vouchers MSZC 198 and MSZC 213) are as follows: call duration 889–1582 ms (1242.0 ± 231.8 ms); notes / call 3–6 (4.3 ± 1.0); note duration 158–308 ms (209.3 ± 33.6 ms); inter-note interval 77–162 ms (120.7 ± 28.8 ms); dominant frequency 4130–4799 Hz (4493 ± 191 Hz); harmonic frequency band present at around 9000 Hz; prevalent bandwidth 3400–5000 Hz.

Distribution.

According to molecular data summarized herein, the species is known from (1) the type locality, Bevitagnono forest, and (2) Andranonafindra forest. The known elevational range of the species spans from 1016–1169 m a. s. l.

Figures

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

Figure 13. Individuals of Boophis archeri sp. nov. in life. A, B male holotype ZSM 12 / 2016 (MSZC 213) from Bevitagnono forest in dorsal and dorsolateral view. C male paratype ZSM 11 / 2016 (MSZC 198) from Andranonafindra forest. D female paratype, ZSM 13 / 2016 (MSZC 243) from Andranonafindra forest.