Mantidactylus majori Boulenger 1896

Mantidactylus majori Oral disc: Oral configuration is described and illustrated in Randrianiaina et al. (2011a) and reproduced here (Fig. 1). SEM micrographs show slight flaking of a keratinized epithelium on the surface of the three, large, thorn-like papillae in the normal position of the upper jaw sheath (Fig. 5A, B); lower jaw sheath U-shaped, slightly keratinized, and marginally smooth (Fig. 5D). B uccalfloor (Fig.5D, E): Fivepairsoftall, conicalinfra-labialpapillae aligned on the posterior margin of Meckel’s cartilage. Tongue anlage with one pair of tall, flat, lingual papillae with pustulated tips. Buccal floor arena delimited by two long, thick crests formed of about 20 transverse ruffled ridges closely spaced (365–375 µm long, 40–200 µm wide; detail in Fig. 5E); crests meet medially thus forming a horse-shoe intricate margin surrounding the whole buccal floor arena. Central region of the arena smooth, except a medial, posterior area where several scattered short, pustulated papillae appear. Buccal pockets oriented transversely. Ventral velum without marginal projections and median notch. Glottis fully covered. Buccal roof (Fig. 5F, G): Prenarial arena with a wide inverted-V crest with smooth margin. Internal nares large and slit-like, transversely oriented; margins thick and mostly smooth, with a long, conical papilla at the anterolateral edge, projecting posteriorly. Median ridge rectangular, taller than wide, and with crenulated free margin. Buccal roof arena entirely ornamented with c. 22 bilateral, transverse, parallel ruffled ridges of densely packed, short papillae; posteriorly to the median ridge, these ridges meet medially with the contralateral one and papillae appear less packed; some larger papillae are scattered along the midline; laterally, each ridge ends in a hand-like flap papilla that recurves medially (detail in Fig. 5G); these flaps are large in the middle section, and gradually decrease in size rostral and caudally. Overall, ridges are 400–830 µm long and 90–160 µm wide, and cover about 45% of the buccal roof. Threedimensional reconstruction of the buccal cavity (Fig. 5C) shows how buccal roof and floor structures align relative to each other, with dorsal crests fitting exactly within the space defined by ventral crests. Unfortunately, the dorsal velum was broken in SEM images.