Rhombophryne testudo Boettger 1880

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Rhombophryne testudo Boettger, 1880 Figures 2, 4 –12 Holotype. SMF 4241 (formerly 1177.2 a), an adult female, collected on an unknown date on ‘ insula Nossi Bé’ (Nosy Be; approx. coordinates 13.2– 13.4°S, 48.2– 48.4°E), Diana Region, Madagascar, by Carl Ebenau (erroneously later designated as a lectotype by Mertens 1967) (Figs 8, 9, 11). Paratypes. None. Boettger (1880 a) states explicitly that the species is based on a single specimen. Referred specimens. Numerous specimens claimed to be syntypes / paralectotypes exist as a result of the erroneous designation of SMF 4241 as lectotype by Mertens (1967). We are not aware of an exhaustive list, but Barbour and Loveridge (1929) stated there were seven in the Museum of Comparative Zoology of Harvard, namely MCZ 2163 (one specimen), 2236 (one), 2731 (three), plus 9317 and 9318 (two). At least one of the specimens in MCZ 2731 was exchanged to the Field Museum of Natural History, where it is archived as FMNH 73363 and incorrectly listed as a ‘ co-type’. A further specimen (EHT-HMS 44690, ex- SMF 4267) is listed as present in the type collection of the University of Illinois Museum of Natural History (Phillips 2015). This is also not a type. Four specimens formerly under catalogue number ZMB 10059 (now divided into ZMB 10059 [one specimen] and 51041–51043) were also originally incorrectly included in the catalogue of the Museum für Naturkunde, Berlin as types of R. testudo, but this was corrected in the digital catalogue. We here examined SMF 4247 –4263 (16 specimens), which Mertens (1967) incorrectly considered paralectotypes — none of these specimens in fact has type status. Additionally, we examined ZSM 474/2000 (FGMV 2000.276) and ZSM 475/2000 (FGMV 2000.277), two adult specimens of uncertain sex, collected on 11 March 2000 on the east coast of Lokobe National Park (13.4133°S, 48.3342°E, 110 m a. s. l.), Nosy Be, Diana Region, northern Madagascar, by F. Glaw, K. Schmidt, and M. Vences; UADBA -A- FGZC 5620, an adult male, collected on 29 April 2019 on the Kindro trail, Ampasindava (13.4099°S, 48.3051°E, ca 80 m a. s. l.), Lokobe National Park, Nosy Be, Diana Region, northern Madagascar, by F. Glaw, M. D. Scherz, and A. Razafindraibe (Fig. 10); and ZMB 51041, an adult female, collected in 1887 on Nosy Be (no precise collection data), Diana Region, northern Madagascar, by C. Reuter (originally part of ZMB 10059). We further examined photographs of the false ‘ syntypes’, MCZ 2163, MCZ 9317, and MCZ 9318, to confirm their identity and morphological agreement with the holotype. Assignment of specimens. All referred specimens are unambiguously assigned to the species based on their overall morphology (the rotund body, short limbs, and chin barbels are unmistakable) and collection around the type locality. ZSM 475/2000 is used as the reference specimen for this species in 16 S rRNA barcoding (16 S 3 ’ EU 341110 / AY 594125; 16 S 5 ’ EU 341110 / AY 594087; Vieites et al. 2009); a sample from either this specimen or ZSM 474/2000, with the tissue number MV 2000 - B 59, was used as the reference for COI barcoding (COI KF 611596 / MH 940140; Perl et al. 2014). These specimens cluster in our mitochondrial phylogeny (Fig. 2). Both specimens are included in the RAG 1 haplotype network (Fig. 4). Definition. Type species of the genus Rhombophryne. Within the R. testudo group, this species is sister to R. matavy (Fig. 2; Belluardo et al. 2022). It is characterised by having the following unique suite of characters: (1) medium to large body size, adult SVL 33.0– 43.1 mm; (2) head much wider than long (HW / HL 2.00–2.60); (3) small eyes (ED / HL 0.23–0.39); (4) short hindlimbs (HIL / SVL 1.18–1.41); (5) large inner metatarsal tubercle (IMTL / FOL 0.15–0.24); (6) generally pronounced outer metatarsal tubercle; (7) second finger slightly shorter than fourth; (8) third toe distinctly longer than fifth; (9) dorsal skin rough with converging paravertebral ridges; (10) presence of chin barbels; (11) absence of pronounced superciliary spines; (12) absence of inguinal ocelli or spots; (13) absence of distinctive markings along the posterior thigh; (14) highly robust skull with very broad squamosal, maxilla, and posterior process of angulosplenial; (15) clavicles absent; and (16) advertisement call (based on 4 analysed calls by one individual) highly pulsed (162–177 pulses per call), with (17) call duration 823–894 ms, (18) inter-call interval 6071–10186 ms, and (19) dominant frequency 508–524 Hz. Rhombophryne testudo is furthermore distinguished from all other Rhombophryne species analysed by the following robust diagnostic nucleotide combination in the mitochondrial 16 S rRNA gene (positions relative to the full 16 S sequence of Anilany helenae MZ 751042): in 16 S 5 ’, ‘ T’ at site 456, ‘ T’ at site 651 and ‘ C’ at site 734; in 16 S 3 ’, ‘ C’ at site 1099, ‘ C’ at site 1179, and ‘ G’ at site 1216. Diagnosis. Within the genus Rhombophryne, R. testudo can easily be distinguished from all other species by the presence of several distinct chin barbels and its fortified skull, and from all species except R. coudreaui, R. matavy, and R. maraorao sp. nov. described below by its rotund body. From R. matavy it can further be distinguished by its pulsed (vs tonal) advertisement call that is much longer (call duration 823–894 ms vs 161–209 ms), and with a lower dominant frequency (508–524 Hz vs 1588–1688 Hz). Redescription of the holotype. A specimen in a good state of preservation, quite stiff and hard, somewhat desiccated (Figs 8, 9). Developing eggs evident in a micro-CT scan of the specimen. Body robust, rhomboid. Head very wide and short, much wider than long (HW / HL 2.45). Eyes small, pupils small, round. Snout obtuse, slightly protruding and rounded in dorsal view, angular in lateral view, with five barbels on it, two slightly above and between the nostrils, two directly below these, and a central one below these over the commissure of the jaws. Canthus rostralis distinct, convex. Loreal region concave, slightly oblique. Nostril openings small, angled anterolaterally, equidistant between tip of snout and eye, slightly protuberant. Tympanum indistinct, vertically oval. TDH / ED 0.827. Supratympanic fold distinct, weakly raised but tubercular and so uneven in height, forming a gentle curve from the line of the top of the eye over the tympanum, sloping down to the posterior of the top of the arm. Superciliary spines are absent but there is a small light-coloured spot centrally above each eye, with several small tubercles on the dorsal surface of the eye. The jaw is firmly shut, such that it is impossible to open without damaging the specimen irreparably. The original description described the specimen as lacking maxillary teeth, having small and weak palatal bones (interpreted as the neopalatines), a simple unfringed ‘ fold’ on the palate, which is interpreted as being the vomerine ridge, as the species lacks proper vomerine teeth (see Variation below), and having a large tongue that is wider than it is long, attached anteriorly and posteriorly free with a longitudinal furrow but without lateral emargination. Given that the jaw is so tightly shut, it is not clear how this information was obtained. Forelimbs relatively short and thick, the upper arm hardly distinguishable from the trunk (FARL / SVL 0.397). Fingers without webbing, all short, relative lengths 1 <2 = 4 <3 (Fig. 9). Finger subarticular tubercles indistinct, single, round; inner metacarpal tubercle large, slightly shorter than first finger (IMCL / HAL 0.278); outer metacarpal / palmar tubercle indistinct, single. Hind limb thick, tibiotarsal articulation extent when adpressed anteriorly along the body cannot be assessed due to strong fixation. TIBL / SVL 0.259. Inner metatarsal tubercle present, large, longer than first toe, roughly as long as second toe (IMTL / FOL 0.193). Outer metatarsal tubercle faint. Toes not webbed; first toe distinctly reduced, toe lengths 1 <2 <5 <

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.