Mantidactylus zipperi, VENCES & GLAW, 2004

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 : 170-171

MANTIDACTYLUS ZIPPERI VENCES & GLAW, 2004

The tadpoles of M. zipperi have no obvious diagnostic characters compared to those of other species of Chonomantis , except for some subtle details of uncertain diagnostic value, and except for M. aerumnalis and M. sp. 59, which can be distinguished, 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. zipperi is based on the DNA voucher specimen in stage 35, ZSM 1825/2007 (field number ZCMV 3532; GenBank accession number GU808508 ) from An’Ala (TL 36.7 mm, BL 12.3 mm). Buccopharyngeal features are described based on the DNA voucher specimen in stage 40, ZSM 1824/2007 (ZCMV 3531; GU808509 ) from An’Ala.

External morphology: In profile ( Fig. 1 ), BW 105% of BH, snout truncate. In dorsal view, see Figure 1 . Eyes moderately sized, ED 13% of BL, slightly bulging, barely visible in ventral view, positioned slightly more dorsally than strictly dorsolaterally. Pineal ocellus present at the level of anterior edge of eye balls. Nares elliptical elongate, positioned more dorsally than strictly dorsolaterally, aperture directed horizontally, RN 43% of NP, NN 72% of PP. Spiracle moderately sized, external wall displaced anteriorly, orientated slightly more posteriorly than strictly posterodorsally; spiracular opening more or less round, directed posterolaterally, at a level situated closer to hindlimb insertion than to apex of myotomes of caudal muscle. Tail musculature, TMH 64% of BH and 72% of MTH, TMW 54% of BW, increasing in height in proximal third then gradually tapering with a sudden reduction in last third, not reaching tail tip. Upper fin absent in proximal third, SU 150% of BL, UF 25% of MTH, increasing suddenly at proximal third then slightly convex in following caudal muscle, lower fin shallow in proximal third, convex, following caudal muscle; tail moderately long, TAL 194% of BL, point of maximum height of tail located just before middle of tail length, MTH 89% of BH. Anal tube moderately small, short, bulging, directed almost posteriorly, linked to ventral tail fin except its distal tip free, opening elliptical. Lateral line organs present on snout and behind eyes until level of spiracular opening. Oral disc ( Fig. 2 ), ODW 35% of BL and 66% of BW. Jaw sheaths white with black serrations; upper jaw sheath with a small median convexity.

Coloration in preservative: Upper side beige covered with relatively big brown dots irregularly arranged forming irregular spots. Flanks with fewer dots than on back, forming smaller spots and so leaving more unpatterned space. Belly translucent with few regularly arranged dots, intestine visible; thorax and throat with numerous regularly arranged dots. Upper part of caudal muscle of same colour as body with same brown dots although more densely arranged, upper fin and anterior upper part of caudal muscle free of fin unpatterned; lateral part with densely arranged dots leaving few irregular depigmented areas, these areas increasing in size and number towards tip of tail, a depigmented area anteriorly on lower half of caudal muscle. Fins translucent; proximal half of upper fin depigmented, distal half with numerous dense spots; two proximal thirds of lower fin depigmented, distal third with some rare dense spotting.

Variation: The ratios taken from three other tadpoles (except for the two ratios involving ODW where only two tadpoles were measured) at stages 39–40 (ZSM 1820/2007, field number ZCMV 3522, GU808510 ; ZSM 1821/2007, ZCMV 3523, GU808511 ; and ZSM 1824/2007 from An’Ala; TL 40.5–44.5 mm, BL 10.5– 11.1 mm) vary in the following proportions: BW 107– 111% of BH; ED 15–16% of BL; RN 46–55% of NP; NN 63–76% of PP; SS 48–55% of BL; TMH 54–67% of BH; TMH 55–69% of MTH; TMW 57–60% of BW; UF 24–25% of MTH; LF 22–25% of MTH; SU 167–177% of BL; TAL 270–292% of BL; MTH 90–100% of BH; ODW 40–53% of BL; ODW 65–86% of BW.

The spiracle can be directed posteriorly. Tail long in these specimens. Lateral line present on upper part of body until tail, and on apex of caudal myotomes and on interface caudal muscle/upper fin on specimen ZSM 1820/2007. Lateral line on tail of other specimens present but hard to see. One specimen (ZSM 1821/2007) with a depigmented mediodorsal line on back extending the depigmented area of upper part of caudal muscle.

Buccal floor ( Fig. 3 ): Prelingual arena trapezoidal, deep, two vertical ridges on inner side of lower beak; two pairs of small and simple prelingual papillae on lateral wall of arena, the anterior pair the lowest, directed dorsomedially. Tongue anlage prominent, almost square; one pair of relatively long and simple lingual papillae orientated posterodorsally. Buccal floor arena oval delimited by a row of seven stocky and very small papillae on each side, the biggest in front of buccal pocket bifid, two posterior-most pairs fine; interior of arena with fewer than 20 faint pustules. Buccal pockets fine, curved, almost obliquely orientated; a row of at least six prepocket papillae on each side continuous with row of buccal floor arena papillae. Ventral velum wavy, with spicular support, bearing a projection above the second filter plate and four fine projections medially on each side (above first filter plate and oesophagus); medial notch present; posterior end of glottis visible through medial notch; no secretory pits visible. Branchial baskets wider than long, curved dorsally; with three filter cavities, filter plates obliquely arranged, filter mesh with main folds and some secondary folds.

Buccal roof ( Fig. 4 ): Prenarial arena rectangular, almost square, two vertical ridges on anterior wall surrounding a depression; one pair of flat and triangular prenarial papillae at posterior end of ridges, orientated ventrally. Choanae moderately sized, transverse; anterior wall slightly elevated, smooth, bearing a small projection halfway; narial valve elevated, forming a rounded flap wrapping medial extremity of choana, a ventrally orientated prominence at extremity of each flap. A large, flat, and rounded flap behind each choana on a prominence, probably homologous to postnarial papilla. Postnarial arena with four pustules. Median ridge as an arrow with a posteriorly directed tip. No lateral ridge papillae. Buccal roof arena without buccal roof arena papillae; interior with very faint pustules, the most prominent anterior. Posterolateral ridge present, prominent, formed by pustules laterally and medially, shortly interrupted medially. Glandular zone present, narrow medially, very big laterally. Dorsal velum margin free, bearing papillae on its free margin, interrupted medially on width of the oesophagus. Secretory pits present behind dorsal velum. 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.