Boophis praedictus, Glaw & Köhler & Riva & Vieites & Vences, 2010

Glaw, Frank, Köhler, Jörn, Riva, Ignacio De La, Vieites, David R. & Vences, Miguel, 2010, Integrative taxonomy of Malagasy treefrogs: combination of molecular genetics, bioacoustics and comparative morphology reveals twelve additional species of Boophis 2383, Zootaxa 2383 (1), pp. 1-82 : 35-40

Boophis praedictus sp. nov.

( Fig. 17 , Appendix 9)

Remark. This species has been referred to as Boophis sp. aff. albilabris "red eyes" by Glaw & Vences (2007:166–167) and as Boophis sp. 5 in Vieites et al. (2009).

Holotype. ZMA 20131 ( ZCMV 678 ), adult female, from Vevembe , 22°47.686' S, 47°11.228' E, 581 m a.s.l., southeastern Madagascar, collected on 10 February 2004 by E. Rajeriarison and M. Vences.

Paratype. ZSM 478 /2009 ( ZCMV 11237 ), subadult female, from a campsite locally known as Ampofoko , Makira forest, 15°25'22.3'' S, 49°07'15.1'' E, 1034 m a.s.l.; collected on 22 June 2009 by M. Vences, D . R. Vieites, F. Ratsoavina , R.- D. Randrianiaina, E. Rajeriarison , T. Rajoafiarison and J. Patton .

Etymology. The specific name is an adjective derived from the Latin "praedictus", meaning "previously mentioned", and refers to the fact that the existence of this species was known from a photograph published in 1993 in which its distinctive character, the red iris periphery, was clearly recognizable.

Diagnosis. Assigned to the genus Boophis based on the presence of an intercalary element between ultimate and penultimate phalanges of fingers and toes (verified by external examination), enlarged terminal discs of fingers and toes, lateral metatarsalia separated by webbing, absence of outer metatarsal tubercle, molecular phylogenetic relationships (see Vieites et al. 2009 for a complete molecular analysis of Boophis ), and overall similarity to other Boophis species. Assigned to the Boophis albilabris group based on the following combination of characters: large size (female SVL 62–89 mm; Appendix 5); well developed webbing between fingers; presence of vomerine teeth; green colouration in life and colouration in preservative with a purple shade; presence of a white line along upper lip; molecular phylogenetic relationships ( Vieites et al. 2009); and overall similarity to B. albilabris . Boophis praedictus differs from the other two described species in the Boophis albilabris group by strong genetic differentiation (see below). It further differs from B. occidentalis by its larger size and different body colouration (absence of yellow dorsolateral stripes) and iris colouration (yellowish iris and red iris periphery vs. turquoise iris and bluish posterior iris periphery), and from B. albilabris by a different colouration of the posterior iris periphery (red vs. whitish or greenish).

Description of the holotype. Adult female, SVL 89.3 mm. Body moderately slender; head slightly longer than wide, slightly wider than body; snout rounded in dorsal view, obtuse in lateral view, nostrils directed laterally, slightly nearer to tip of snout than to eye; canthus rostralis sharp in cross section, slightly concave in dorsal view, loreal region slightly concave; tympanum distinct, rounded, TD 60% of ED; supratympanic fold thin, distinct; vomerine odontophores distinct, well separated in two elongated patches, positioned posteromedial to choanae; choanae medium-sized, elongated. Tongue posteriorly bifid, free. Arms slender, subarticular tubercles single, round; metacarpal tubercles not recognizable; fingers broadly webbed and with lateral dermal fringes; webbing formula 1(1), 2i(1.5), 2e(0), 3i(1.25), 3e(0), 4(0); relative length of fingers 1<2<4<3 (finger 2 distinctly shorter than finger 4); finger discs enlarged. Hindlimbs slender; tibiotarsal articulation barely reaching nostril when hindlimb is adpressed along body; lateral metatarsalia separated by webbing; inner metatarsal tubercle small, distinct, elongated; no outer metatarsal tubercle; toes almost fully webbed; webbing formula 1(0), 2i(0.25), 2e(0), 3i(0.25), 3e(0), 4i(0.25), 4e(0.25), 5(0); relative length of toes 1<2<5=3<4; toe discs enlarged. Skin finely granular on dorsal surfaces, smooth on throat and chest, coarsely granular on belly and ventral surfaces of thighs. A tissue sample was removed from the right thigh.

Measurements (in mm): SVL 89.3, HW 32.0, HL 33.3, ED 10.4, END 7.6, NSD 7.4, NND 9.5, TD 6.3, TL 45.8, HAL 27.9, FOL 40.8, FOTL 65.9.

After almost four years in preservative, ground colour of upper surface of head and dorsum dark greyish purple with scattered small, dark cream dots. A diffuse stripe at midflanks, paler than dorsum; lower flanks creamy yellow with irregular blotches of the same colour as dorsum. A creamy white, narrow stripe on upper lip, lateral edge of lower arm, tarsus, and heel. Ground colour of ventral surfaces uniformly creamy yellow; a dark greyish purple line along the lower jaw. Posterior surfaces of thighs cream with a purple reticulation. Posterior part of eye purplish.

In life, dorsal surfaces green with scattered small, cream dots. Lower flanks cream with irregular greenish grey blotches. A white, narrow stripe on upper lip, lateral edge of lower arm, tarsus, and heel. Upper surfaces of thighs and shanks the same colour as dorsum, with darker bars. Iris golden with brown reticulations, more densely arranged around the pupil; eye periphery red posteriorly ( Fig. 17 ). Upper surface of fingers, toes and terminal discs reddish. Ventral life colouration of holotype unknown.

Natural history. A single female of this species was collected at night, sitting about 2 m high in the vegetation, along a stream in disturbed rainforest.

Molecular relationships. The phylogenetic tree of species assigned to the Boophis albilabris group ( Fig. 16 ) provides evidence for a large molecular homogeneity of the species B. albilabris across its entire distribution range: sequences from Manongarivo in the Sambirano region in northern Madagascar showed almost no differences to sequences from Andasibe in the Northern Central East (0.6%), Ranomafana in the Southern Central East (0.4%), and Andohahela in the South East (0.2%). On the contrary, specimens from Berara forest (Sahamalaza Peninsula in the North West) previously assigned to B. occidentalis by Andreone et al. (2002) are divergent (3.1–3.3%) as compared to topotypical specimens from Isalo (see also Glaw & Vences 2007). The Berara population probably merits recognition as separate species and will be subject of a forthcoming study. The specimen of B. praedictus studied here is placed basally in the phylogeny and has a strong differentiation to all other species in the group (4.4–4.8% to B. albilabris ; 4.4–4.6% to B. occidentalis and B. sp. aff. occidentalis ).

Distribution. At present Boophis praedictus is known from (1) its type locality, Vevembe, and from three localities at the border between the Northern Central East and North East regions: from (2) Makira Reserve (paratype specimen), (3) Ambatovaky Special Reserve (Appendix 10), based on a photograph by C. J. Raxworthy reproduced in Blommers-Schlösser & Blanc (1993), and (4) Masoala based on a photograph by O. Jovanovic (not reproduced here) that shows a specimen probably belonging to this species as well, although the colour of the iris periphery is less distinctly visible. In both these photographs, the red iris periphery typical for B. praedictus is clearly recognizable.

Available names and justification. Boophis albilabris ( Boulenger, 1888) was described based on a single adult holotype, reportedly a male specimen from "eastern Imerina". The Imerina, one of Madagascar's indigenous tribes, inhabit the central portion of the high plateau in the vicinity of Antananarivo, but B. albilabris is unlikely to have occurred in this now deforested area and the type most likely came from the rainforest escarpment to the east ( Cadle 1995). The species so far usually considered to be B. albilabris (e.g., Cadle 1995; Andreone et al. 2002; Glaw & Vences 2007), and the species with red eye periphery here described as B. praedictus , both occur on the eastern escarpment. To assess the identity of the nomen albilabris we examined the holotype in the Natural History Museum, London (BMNH 1947.2.9.16) which is in moderately good state of preservation and we assume is probably a female, not a male specimen. The identity of this specimen is not unambiguous as it shares characters that seem to characterize either of the two species known, requiring a careful evaluation of its identity and the taxonomic consequences.

The two female type specimens of B. praedictus and photographs of additional females with reddish iris periphery assigned to that species seem to differ from most specimens assigned to B. albilabris by (1) the colouration of the flanks below the dorsolateral border which differs from the dorsal colouration, (2) more strongly developed white dermal ridge along the elbow and the lower arm, and (3) generally fewer, broader and less distinct crossbands on the hindlimbs. The holotype of albilabris is uniformly light purple, indicating that it probably was uniformly green in life, which agree with Boulenger's (1888) statement of a green colour in life in the original description. Crossbands on the hindlimbs are not recognizable, the skin on the flanks is shrinked and of greyish colour, and there is a prominent white ridge on heel and elbow. However, regarding the latter character, we have observed that this is a sexually dimorphic character in several species of the B. albilabris group (such as B. occidentalis ), being in general more prominent in female specimens than in males, which have more muscular forelimbs (and most specimens assigned to B. albilabris known to us are males). The lack of crossbands on the limbs and the lack of purple (originally green) colour on the flanks can be due to fading of these pigments during the long period of preservation, and additionally weak expression of crossbands and dense marbling with colours other than green also occurs in some specimens of the species usually assigned to B. albilabris .

One additional piece of evidence to take in mind is the distribution of the two species. Although both occur in eastern rainforests, the species usually assigned to B. albilabris has been commonly encountered and photographed by multiple researchers and tourists in localities of mid-altitude (900–1100 m a.s.l.) of the eastern escarpment, some of which are close to the highland Imerina area (e.g. Andasibe). In contrast, the species described as B. praedictus has usually been found at lower elevations, and in particular in the north-east in Masoala. It is unlikely that any of these low-elevation localities would have been characterized as "eastern Imerina" by early collectors. However, the situation is complicated by the presence of B. praedictus at Makira at an elevation of above 1000 m a.s.l., and by its possible presence in An'Ala, a locality near Andasibe but at slightly lower elevation and known to contain faunal elements typical for low-elevation sites. This latter record is based on tadpoles only and became available after the present paper had been accepted for publication; it needs further study as it may indicate a contact zone between the two species between An'Ala and Andasibe. It also became recently clear that subadult specimens from Masoala and Mananara considered as separate candidate species Boophis sp. aff. albilabris "reticulated lips" (see Glaw & Vences 2007) probably correspond to subadults of B. praedictus ; this provides another character (juvenile colour pattern) clearly distinguishing this form, and further confirms its presence at mainly east coast sites of low elevation. This evidence will be reported more in detail in forthcoming studies.

Eventually, the most important character distinguishing B. praedictus from the specimens usually assigned to B. albilabris is its red iris periphery. This is a conspicuous character that in our specimens, after several years in preservative, is still recognizable. Boulenger (1888) noted that the holotype of albilabris was green in life, suggesting that he had a fresh specimen or additional information available, but he did not mention any reddish iris periphery. Upon examination in 2009, the iris periphery of the albilabris holotype is uniformly light grey to silver without traces of red or orange colour, in full agreement with the species usually considered to be B. albilabris . There obviously remain doubts whether the colour of the iris periphery in the albilabris holotype may have faded over the past ca. 120 years, but there is no evidence that it was redddish in life shortly after preservation.

Summarizing, we conclude that there is no clear evidence supporting the albilabris holotype to be conspecific with the species here described as B. praedictus : similarities can either be explained by sexual dimorphism (heel and elbow ridges) or by partly faded colour pattern in the albilabris type (lack of limb crossbands and light flank colour) and furthermore fall into the variability of the species usually assigned to B. albilabris . In contrast, the lack of dark (red in life) pigment in the iris periphery and the type locality "Imerina" support that the species with light iris periphery common in the Andasibe and Ranomafana areas, and hence in at least some localities bordering the Imerina region, are to be considered as B. albilabris . Since this definition of B. albilabris is also in accordance with most accounts that provided data on the biology, morphology and colouration of this species (in particular Andreone 1993; Cadle 1995; Andreone et al. 2002), taxonomical stability is best served by accepting the evidence from biogeography and iris colour (although it is not unambiguous) and to continue the prevalent definition of B. albilabris , describing the mainly lowland species with red iris periphery as the new species Boophis praedictus .

Figures

FIGURE 16. Maximum parsimony 16S rRNA phylogram for species in the Boophis albilabris group. From 535 total characters, 445 were constant and 35 parsimony informative. MP searches retained 6 trees of which a strict consensus is shown. Consensus support values higher than 50, from 2000 bootstrap replicates, are shown; an asterisk indicates Bayesian posterior probabilities equal or higher than 95%. The species newly described herein is in bold.

FIGURE 17. Female holotype of Boophis praedictus sp. nov. (ZMA 20131) from Vevembe.