Scaphiophryne spinosa, Steindachner, 1882

Grosjean, Stéphane, Glos, Julian, Teschke, Meike, Glaw, Frank & Vences, Miguel, 2007, Comparative larval morphology of Madagascan toadlets of the genus Scaphiophryne: phylogenetic and taxonomic inferences, Zoological Journal of the Linnean Society 151 (3), pp. 555-576 : 564-565

SCAPHIOPHRYNE SPINOSA STEINDACHNER, 1882

Specimens were collected from an ephemeral pond in the forest of Ranomafana National Park. The muddy bottom of the pond was completely covered with dead leaves and it had a maximal water depth of 20 cm. The water was clear. The external morphological description is based on a specimen at stage 30, ZSM 602/2004 (BL is 9.7 mm, DNA voucher, with part of the tail missing for molecular determination), and a specimen at stage 30, ZSM 603/2004, which served for verification, calculation of the ratios and tail description (TL and BL are 22.6 and 10.4 mm, respectively). The drawings are based on a specimen at stage 29 (ZSM 604/2004). Buccopharyngeal features are based on a tadpole at stage 29, ZSM 612/2004. One specimen was used for the photographic documentation ( Fig. 4 ).

External morphology: In dorsal view ( Fig. 1E ), body discoid. In profile ( Fig. 1F ), body almost flat above and below, BW 129% of BH, snout vertical and directed slightly upward. Eyes small, ED 7% of BL, not bulging. RN 167% of NP, NN 24% of PP. Spiracle formed by a square piece of skin, large, SS 80% of BL; spiracular opening clinging to the body wall, on a plane situated just above the opening of ventral tube. TMH 28% of BH and 30% of MTH, maximum height of tail musculature reached at the proximal quarter of the tail. UF 38% of MTH, LF 38% of MTH; point of maximum height of tail located between the proximal third and the middle of tail length, MTH 95% of BH. Ventral tube tubular but its posterior part folded against ventral fin.

Oral disc ( Fig. 2G ) in position and orientation terminal, ODW 32% of BL and 38% of BW. A row of submarginal papillae separated from the row of marginal papillae on the upper labium, a row of submarginal papillae separated from the row of marginal papillae on the lower labium with a cluster of small papillae between the extremities of this row and the lower jaw sheath; papillae round, stocky, some of them blunt, those on the top of upper labium very small, submarginal papillae positioned posterolaterally from the lower beak smaller. Jaw sheaths white; upper jaw sheath a large arch, flat on the most part; lower jaw sheath U-shaped, narrow.

Coloration in preservative: Tadpole transparent, all underlying organs visible. External tissue of upper side and upper flanks transparent, underlying tissues bearing numerous small light brown spots, more densely distributed around the digestive tract, a few small light brown spots on the external tissue at the level of gills laterally. Lower flanks and ventral side immaculate and perfectly transparent. Upper half of caudal muscle bearing a high density of the same small light brown spots, very few on the lower half. Fins immaculate except 2–3 blots on the upper fin near the caudal muscle.

Variation: The ratios taken on ten tadpoles at stages 27–30 (ZSM 604/2004-ZSM 613/2004) vary in the following proportions: BW 128–142% of BH; RN 127– 167% of NP; NN 23–27% of PP; SS 75–86% of BL; TMH 27–37% of BH; TMH 24–33% of MTH; UF 34– 40% of MTH; LF 35–40% of MTH; SU 93–100% of BL; MTH 106–116% of BH; ODW 29–34% of BL; ODW 35– 43% of BW. The spiracle can be orientated in a more posterodorsal than almost posterior direction, but is never fully posterodorsal.

Buccal floor ( Fig. 2H ): Prelingual arena small, two pustules anteriorly on the internal wall of the beak and two small filiform papillae laterally; a pair of small prelingual papillae on the lateral wall of the arena, directed dorsally; a single medial curved gutter-shaped papilla originating from the floor of the prelingual arena, the laterodistal projections highly developed. Buccal floor arena round, delimited posteriorly by a transversal row of about 15 large papillae. Buccal pockets wide, deep, transversely orientated, unperforated; two small prepocket papillae. A pair of projections on each half of the ventral velum medially, a small papillae in front of the glottis; secretory pits not obvious. Branchial baskets longer than wide.

Buccal roof ( Fig. 2I ): Prenarial arena wide and triangular. Anterior wall of choanae pustulate; narial valve greatly enlarged into an elongate structure not curved dorsally, covering the posterior end of the choana. Postnarial arena small and concave, without ornamentation. Median ridge irregularly shaped with a wide median cleft. The larger pair of lateral ridge papillae roughly triangular and smooth. Buccal roof arena non-existent, interior without ornamentation. Posterolateral ridge continuous through buccal roof, more prominent laterally. Glandular zone present anteriorly to dorsal velum, uninterrupted across buccal roof. Secretory pits not obvious on the posterior side of the dorsal velum.

Figures

Figure 1. Dorsal and lateral views of tadpoles of Scaphiophryne madagascariensis (stage 35, ZSM 595/2004) (A, B), S. menabensis (stage 35, ZSM 413/2004) (C, D), S. spinosa (stage 29, ZSM 604/2004) (E, F), S. brevis (stage 31, ZSM 618/ 2004) (G, H) and S. calcarata (stage 31, ZSM 410/2004) (I, J). Scale bars represent 5 mm.

Figure 2. Oral disc (OD), buccal floor (BF) and buccal roof (BR) of tadpoles of Scaphiophryne madagascariensis (OD: ZSM 600/2004; BF, BR: stage 38, ZSM 599/2004) (A–C), S. menabensis (OD: stage 36 BF, BR: stage 36); all from specimens in batch ZSM 413/2004) (D–F), S. spinosa (OD: stage 28, ZSM 616/2004; BF, BR: stage 29, ZSM 612/2004) (G–I), S. brevis (OD: stage 34; BF, BR: stage 31, ZSM 619/2004) (J–L) and S. calcarata (OD: stage 34; BF, BR: stage 32; both from specimens in batch ZSM 410/2004) (M–O). Scale bars are indicated on the images.

Figure 4. Dorsal, lateral, and ventral views of a tadpole of Scaphiophryne spinosa (ZSM 606/2004) showing the typical morphology of the relatively large tadpoles of the Scaphiophryne (Scaphiophryne) type.