Mantidactylus

Schmidt, Heike, Glaw, Frank, Teschke, Meike & Vences, Miguel, 2009, Description of tadpoles of five frog species in the subgenus Brygoomantis from Madagascar (Mantellidae: Mantidactylus), Zootaxa 1988, pp. 48-60 : 55-56

Mantidactylus sp. aff. curtus "Ankaratra"

Series examined. Four tadpole series, ZSM 570/2008 (9 specimens; field number ZCMV 2601), ZSM 564/ 2008 (5 specimens; field number ZCMV 2607), ZSM 565/2008 (5 specimens; fieldnumber ZCMV 2609), ZSM 571/2008 (5 specimens; fieldnumber ZCMV 2615), all collected by R.D. Randrianiaina and D. R. Vieites on 14–15 February at Ambohimirandrana, Ankaratra Massif, Central Madagascar, in a mountain stream above the tree line, bordered by only isolated trees and bushes. The stream was of about 1 m width and rather fast-flowing. The collecting site was below a cascade. Mantidactylus sp. aff. curtus was one of the most common frogs along this stream.

Taxonomic note. Previous tadpole descriptions under the name Mantidactylus curtus by Arnoult & Razarihelisoa (1967) and Blommers-Schlösser (1979) likely refer to this species and not to M. curtus , because no specimens from near the M. curtus type locality were studied and genetic data indicate that the populations previously assigned to M. curtus are genetically highly divergent, with different areas and massifs in central Madagascar harbouring exclusive species of the complex (Andringitra: M. bourgati ; Itremo and Antoetra areas: M. curtus ; Ankaratra: M. sp. aff. curtus "Ankaratra"; Ambohitantely / Tampoketsa d'Ankazobe: M. sp. aff. curtus "Ambohitantely").

In the descriptions of Arnoult & Razarihelisoa (1967) an error in the drawings of mouthparts was detected ( Blommers-Schlösser 1979). In the study of Blommers-Schlösser (1979), additional specimens from the locality Angavokely were also used for the descriptions. Because specimens from this site have not yet been studied genetically, it is at present uncertain if the description of Blommers-Schlösser (1979) may refer to a composite of species. We here provide a redescription of tadpoles of M. sp. aff. curtus “Ankaratra based on reliably identified specimens, all from the Ankaratra Massif.

Description. Based on the DNA voucher tadpole of the series ZSM 570/2008 (Genbank accession number EU717889 ; Figure 4 ). Tadpole in developmental stage 36, and in good state of preservation (a part of the ventral tail has been excised for DNA analysis). BL 17.0 mm, TL 46.2 mm, for further measurements see Table 1 . Colouration of preserved tadpole dark to light brown with a slightly yellowish transparent shade. Head and body slightly separated by a constriction of body wall at plane of spiracle. Behind this separation, at the end of body, dark brown colouration in dorsal and lateral view. Next to each nostril, a dark brown coloured short line visible through transparent skin, not visible in ventral view. In dorsal and lateral view, large irregular brown spots, particularly concentrated on posterior fourth of tail. Belly and first two-thirds of ventral caudal fin lacking these darker spots. In dorsal view body shape elongated-elliptical. In lateral view, body depressed, BW 1.32 of BH. Body shape in lateral view without a distinct flattening toward snout. Nostrils rimmed with a mediodorsal projection giving them an arrow shape, not protuberant, positioned dorsolaterally, IND 0.63 of IOD. Nostrils closer to tip of snout than to eyes. Eyes positioned dorsally, directed dorsolaterally, ED 0.12 of BL, not protuberant. Spiracle sinistral, attached to body wall but its inner wall lifting up from body wall to tip. Spiracular opening oval, oriented posteriorly, slightly visible in dorsal view, upper margin situated under level of lower margin of eye, slightly closer to snout than to end of body, ESD 0.21 of BL. Intestinal spiral slightly visible in lateral view and well visible in ventral view, not visible in dorsal view. Medial vent tube with lateral displacement, dextral. Caudal musculature well developed, TMH 0.87 of BH and 0.71 of MTH. Dorsal fin originating at body-tail junction, vastly increasing in height at proximal quarter of tail, MTH 1.23 of BH, equal height throughout two-thirds of tail, slightly diminishing to finely rounded tip. Dorsal and ventral fin convex in outline, nearly equally sized. Oral disc small, generalized, laterally emarginated, ODW 0.33 of BL and 0.69 of BW, anteroventrally positioned, transversely rounded. Oral disc margins not visible in dorsal view, but visible in lateral view. Total number of papillae 91. LTRF 5(2–5)/3(1), about 30 teeth per mm in A2. Large medial gap in second anterior tooth row. Only the first posterior row with small medial gap.

Upper labium with large dorsal gap, upper and lower labium with two continuous rows of papillae. Papillae with a rounded tip, few of them pigmented, sporadically with a pointed tip. Dark coloured beak which slightly lost keratinisation to the border. Upper jaw sheath M-shaped, lower jaw sheath V-shaped, both with almost equal-sized serrations.

Variation. To summarize variation we grouped specimens from all series based on their developmental stages. 12 specimens were in stages 25–30: stage 25 (1 specimen), 28 (2 specimen), 29 (3 specimens) and 30 (6 specimens). Proportions: BW 1.15–1.51 of BH, IND 0.42–0.62 of IOD, ED 0.07–0.13 of BL, ESD 0.21–0.28 of BL, TMH 0.72–0.97 of BH, TMH 0.68–0.85 of MTH, MTH 0.74–1.5 of BH, ODW 0.29–0.36 of BL, ODW 0.52–0.79 of BW, TAL 1.59–2.35 of BL, BL 0.30–0.39 of TL, TAL 0.61–0.70 of TL. LTRF: 5(2–5)/3(1); 4(2–4)/3(1). Labial teeth per mm in A2: 27–34. Numbers of papillae: 66–113.

11 additional tadpoles were in stages 31–38: stage 31 (1 specimen), 32 (2 specimens), 33 (4 specimens), 34 (2 specimens), 35 (1 specimen), 38 (1 specimen). Proportions: BW 1.24–1.60 of BH, IND 0.39–0.83 of IOD, ED 0.08–0.13 of BL, ESD 0.20–0.27 of BL, TMH 0.58–1.13 of BH, TMH 0.69–0.89 of MTH, MTH 0.74–1.45 of BH, ODW 0.25–0.35 of BL, ODW 0.46–0.80 of BW, TAL 1.56–2.49 of BL, BL 0.29–0.39 of TL, TAL 0.63–0.71 of TL. LTRF: 5(2–5)/3(1); 4(2–4)/3(1) (small non-medial gaps in some specimens in A1, here interpreted as oral deformities). There was no obvious correlation between the number of tooth rows and developmental stages of the tadpoles. Labial teeth per mm in A2: 24–31. Numbers of papillae: 76–100.

In earlier stages the skin is less brownish and often more transparent. Behind the separation at the end of the body, sometimes dark brown colouration in dorsal and lateral views and in other cases (not age-related) light brown in dorsal view.

Figures

FIGURE 4. Drawings of the preserved DNA voucher tadpole of Mantidactylus sp. aff. curtus Ankaratra (stage 36), series ZSM 570 / 2008; (a) oral disc, (b) dorsal view, (c) lateral view. Scale bars represent 1 mm.