Mantidactylus opiparis, (PERACCA, 1893)

Grosjean, Stéphane, STRAUss, Axel, Glos, Julian, Randrianiaina, Roger-Daniel, Ohler, Annemarie & Vences, Miguel, 2011, Morphological and ecological uniformity in the funnel-mouthed tadpoles of Malagasy litter frogs, subgenus Chonomantis, Zoological Journal of the Linnean Society 162 (1), pp. 149-183 : 169-170

MANTIDACTYLUS OPIPARIS ( PERACCA, 1893)

The tadpole of this species was described by Blommers- Schlösser (1979) but without certainty of allocation because of the high species diversity of Chonomantis in central-eastern Madagascar from where her specimens originated ( Vences & Glaw, 2004).

According to our data the tadpoles of M. opiparis have no obvious diagnostic characters compared to those of other species of Chonomantis , except for the presence of a thin vertebral line in many (but not all) specimens, that we did not detect in other species, plus some subtle details of uncertain diagnostic value, and except for M. aerumnalis and M. sp. 59, which can be distinguished from M. opiparis , respectively, by their coloration and by the presence of rudimentary keratodonts (see accounts on these species for details).

The description of the external morphology of the tadpoles of M. opiparis is based on the DNA voucher specimen in stage 25, ZSM 416/2004 (field number FGMV 2002.1605; GenBank accession number GU808503 ) from An’Ala (TL 39.9 mm, BL 10.0 mm). A second specimen from the same batch, in stage 25, was used for the description of the tail, measurements, and drawings (TL 39.3 mm, BL 9.67 mm). Buccopharyngeal features are described based on the DNA voucher specimen at stage 25, ZSM 422/2004 (field number FGMV 2002.1662; GenBank accession number GU808505 ) from Fierenana, and another DNA voucher in stage 27, ZSM 418/2004 (FGMV 2002.1632; GU808506 ) from Andasibe, was used for verification.

External morphology: In profile ( Fig. 1 ), BW 119% of BH. In dorsal view ( Fig. 1 ), widest both at level of gills and middle part of intestine. Eyes not visible in ventral view. Nares ovoid elongate, positioned more dorsally than strictly dorsolaterally, aperture directed horizontally, RN 54% of NP, NN 66% of PP. Spiracle conical, small, lateral, external wall displaced anteriorly, closer to end of body than to tip of snout, SS 57% of BL; spiracular opening round, directed posterolaterally, at level of mediolateral line. Tail musculature, TMH 87% of BH and 70% of MTH, TMW 75% of BW, parallel in proximal third then gradually tapering. Upper fin shallow in proximal third, increasing at proximal third then slightly convex in following caudal muscle, SU 166% of BL, lower fin convex, following caudal muscle, LF 26% of MTH; TAL 303% of BL, point of maximum height of tail located just before middle of tail length, MTH 123% of BH. Anal tube moderately small, short, tubular, directed more posteriorly than posterolaterally, linked to ventral tail fin except its distal tip free, opening elliptical. Lateral line organs present on snout and until behind eyes.

Oral disc ( Fig. 2 ), ODW 36% of BL and 64% of BW. The large and round structure on midline of lower labium medium sized relative to other species. Jaw sheaths transparent except serrations of lower jaw sheath brown.

Coloration in preservative: Upper side orange-brown, lighter on tip of snout and around eyes. Flanks transparent with irregular orange-brown zones. Ventral side transparent, internal organs visible through skin, some orange-brown spots of different size laterally and on throat. Caudal muscle orange-brown except depigmented proximal part of upper part and proximal half of lower part. Fins translucent with irregular blotches on posterior part of lower fin and on upper fin (fewer anteriorly) leaving very light depigmented areas.

Variation: Based on 18 other DNA voucher tadpoles at stages 25–28: ZSM 416/2004 from An’Ala; ZSM 418/ 2004 and ZSM 419/2004 (field number FG/MV 2002.1633; GenBank accession number GU808507 ) from Andasibe; ZSM 422/2004 from Fierenana, ZSM 448/2004 ( FG / MV 2002.1877 ; GU808504 ) ; ZSM 586/ 2007 (T0257; GU808473 ) ZSM 720/2007 (T0254; GU808470 ) ; ZSM 1052/2007 (T0255; GU808471 ) ; ZSM 1059/2007 (T0256; GU808472 ) ; ZSM 734/2007 ( ZCMV 5152 ; GU808468 ) ; ZSM 1299/2007 ( ZCMV 4481 ; GU808469 ) ; ZSM 60/2008 ( ZCMV 4988 ; GU808474 ) ; and ZSM 126/2008 ( ZCMV 4628 ; GU808475 ) from Ranomafana National Park ;

These tadpoles (TL 24.7–43.9 mm, BL 7.4–11.8 mm) vary in the following proportions: BW 107–124% of BH; ED 13–17% of BL; RN 35–74% of NP; NN 59–73% of PP; SS 46–59% of BL; TMH 71–87% of BH; TMH 63–82% of MTH; TMW 53–75% of BW; UF 23–29% of MTH; LF 22–27% of MTH; SU 91–175% of BL; TAL 230–293% of BL; MTH 98–131% of BH; ODW 30–41% of BL; ODW 51–76% of BW. The maximum height of tail can be reached just after halfway. The ventral side of the tadpole can be almost entirely covered of small points except the posterior part. A fine grey mediodorsal line as displayed in Figures 1J and 5F 6–F 7 (although usually very fine and straight) can be present or absent.

Buccal floor ( Fig. 3 ): Prelingual arena very small and deep, two vertical ridges on inner side of lower beak, ridges reappearing just before tongue anlage after being interrupted in bottom of arena; two pairs of small and simple prelingual papillae, the most anterior pair the lowest on lateral wall of arena. Tongue anlage prominent, roughly trapezoidal, the largest side anterior and curved backwards; one pair of relatively long and simple lingual papillae orientated posterodorsally. Buccal floor arena oval, seven and eight small buccal floor arena papillae on each side in an oblique row orientated posteromedially, the three ones in front of buccal pocket the largest; interior with about 30 very faint pustules, the most prominent posterior. Buccal pockets narrow, obliquely orientated and strongly curved anteriorly; a longitudinal row of seven prepocket papillae on each side in continuity with buccal floor arena papillae. Ventral velum with spicular support, wavy, bearing a very small projection above third filter plate, a projection above both second and first filter plates, six projections medially between filter plates, the two median forming the median notch; glottis entirely covered by velum; no secretory pits visible. Branchial baskets wider than long; with three filter cavities, filter plates obliquely arranged, filter mesh with main folds and some secondary folds.

Buccal roof ( Fig. 4 ): Prenarial arena rectangular, a medial and vertical depression on anterior wall, following upper beak; one pair of flat and triangular prenarial papillae at posterior end of depression, orientated ventrally. Choanae moderately sized, transverse; anterior wall slightly elevated, smooth, bearing a small papilla on lateral half; narial valve elevated, forming a rounded flap wrapping medial extremity of choana with an anteriorly orientated prominence of each flap. A large, flat, and rounded flap behind each choana on a prominence, probably homologous to postnarial papilla. Postnarial arena without ornamentation. Median ridge arrow-like, with tip directed posteriorly, a pustule on each side of longitudinal branch. No lateral ridge papillae. Buccal roof arena round; two tiny buccal roof arena papillae on each side, the biggest pair laterally, the smallest pair posterolaterally; interior of arena with about 60 faint pustules. Posterolateral ridge present and prominent, raised, not continuous across dorsal roof, two pustules above the lateral end of posterolateral ridge in a longitudinal row. Glandular zone vertical with relatively large secretory pits. Dorsal velum damaged during dissection but seemingly interrupted medially, lateral parts free, bearing papillae on their margins. Pressure cushions not evident, maybe damaged during dissection.

Figures

Figure 1. Lateral and dorsal views of tadpoles of Mantidactylus belonging to the subgenus Chonomantis. Mantidactylus albofrenatus, specimen in stage 26 from the batch ZSM 420/2004. Mantidactylus brevipalmatus, specimen ZMA 7078 in stage 28. Mantidactylus delormei, specimen ZSM 440/2004 in stage 40 (coloration of specimen largely faded and therefore only outline drawn). Mantidactylus melanopleura, specimen ZSM 1318/2007 in stage 26. Mantidactylus opiparis, a specimen from the batch ZSM 416/2004 in stage 25. Mantidactylus zipperi, specimen ZSM 1825/2007 in stage 35. Mantidactylus sp. 59, specimen ZSM 707/2007 in stage 27. Scale bars = 10 mm.

Figure 2. Oral discs of tadpoles of Mantidactylus belonging to the subgenus Chonomantis. Mantidactylus albofrenatus, specimen in stage 26 from the batch ZSM 420/ 2004. Mantidactylus brevipalmatus, specimen ZMA 7080 in stage 27. Mantidactylus delormei, specimen ZSM 440/ 2004 in stage 40. Mantidactylus melanopleura, specimen ZSM 415/2004 in stage 25. Mantidactylus opiparis, specimen from the batch ZSM 416/2004 in stage 25. Mantidactylus zipperi, specimen ZSM 1821/2007 in stage 39. Mantidactylus sp. 59, specimen ZSM 707/2007 in stage 27. Note that the oral disc of M. sp. 59 is drawn in frontal view (all other drawings in dorsal view), and that it contains a row with a low number of keratodont-like structures. Scale bars = 1 mm.

Figure 3. Scanning electron microscopic pictures of buccal floor in tadpoles of Mantidactylus belonging to the subgenus Chonomantis. Mantidactylus albofrenatus, a specimen in stage 26 from the batch ZSM 420/2004. Mantidactylus brevipalmatus, specimen ZMA 6991 in stage 36. Mantidactylus zipperi, specimen ZSM 1824/2007 in stage 40. Mantidactylus sp. 59, specimen ZSM 1079/2007 in stage 27. Mantidactylus delormei, specimen ZSM 446/2004 in stage 36. Mantidactylus melanopleura, specimen ZSM 461/2004 in stage 38. Mantidactylus opiparis, specimen ZSM 422/2004 in stage 25. Scale bars = 1 mm.

Figure 4. Scanning electron microscopic pictures of buccal roof in tadpoles of Mantidactylus belonging to the subgenus Chonomantis. Specimens and stages as in Figure 3. Scale bars = 1 mm.

Figure 5. Life coloration of tadpoles of six species of Mantidactylus in the subgenus Chonomantis, sampled in Ranomafana National Park in February and March 2007. Mantidactylus aerumnalis, A1/A3/A5: ZSM 249/2007 lateral/ ventral/dorsal, A2/A4/A6: ZSM 505/2007 lateral/ventral/dorsal; Mantidactylus delormei, B1: ZSM 1410/2007 dorsal; Mantidactylus melanopleura, C1/C4: ZSM 837/2007 lateral/ dorsal, C2: ZSM 1141/2007 lateral, C3: ZSM 1318/2007 lateral, C5: ZSM 1123/2007 dorsal, C6: ZSM 685/2007 dorsal, C7: ZSM 652/2007 dorsal; Mantidactylus sp. 59, D1/D3: ZSM 797/2007 lateral/dorsal, D2/D4: ZSM 1208/2007 lateral/dorsal; Mantidactylus sp. 13, E1: ZSM 70/2008 lateral, E2: ZSM 74/2008 dorsal. Mantidactylus opiparis, F1/F4: ZSM 706/2007 lateral/dorsal, F2/F5: ZSM 797/2007 lateral/dorsal, F3/F6: ZSM 118/2007 lateral/dorsal, F7: ZSM 622/2007 dorsal. Scale bars = 10 mm.

Figure 6. Results of multivariate morphometric analysis of tadpoles of Mantidactylus species in the subgenus Chonomantis (DNA voucher specimens only). A: plot of discriminant functions based on all 18 measurements; B: plot of principal component factor 1 against factor 2.

Figure 7. Histogram showing the mean preferences for microhabitat structures by tadpoles of six Mantidactylus species in the subgenus Chonomantis, sampled during a tadpole community study in Ranomafana National Park. Ivlev’s electivity index (E, Ivlev, 1961) is plotted for each species and each microhabitat. Positive values indicate that microhabitat was used more often than expected by chance, negative values represent an avoidance of microhabitat structure. Missing bars show that the respective microhabitat was not available to the specific species.