Leptodactylodon mertensi Perret, 1959

Mapouyat, Lissa, Hirschfeld, Mareike, Rödel, Mark-Oliver, Liedtke, H. Christoph, Loader, Simon P., Gonwouo, L. Nono, Dahmen, Matthias, Doherty-Bone, Thomas M. & Barej, Michael F., 2014, The tadpoles of nine Cameroonian Leptodactylodon species (Amphibia, Anura, Arthroleptidae), Zootaxa 3765 (1), pp. 29-53 : 37-39

Leptodactylodon mertensi Perret, 1959

We examined 48 tadpoles, all from Mount Manengouba: ZMB 78499 (two tadpoles, Gosner stages 25 & 40, Ebonemin, 5°1’33.42” N, 9°45’46.74”E, 1356 m, 13 December 2010); ZMB 78500 (eight tadpoles, Gosner stages 25 & 42, Ebonemin, 5°0’46.5”N, 9°45’46.74”E, 1372 m, 16 December 2010); ZMB 78501 (one tadpole, Gosner stage 25, Ebonemin, 5°0’46.5”N, 9°46’5.8”E, 1372 m, 7 October 2011); ZMB 78503 (one tadpole Gosner stage 25, Ebonemin, 5°1’6.2”N, 9°46’16.8”E, 1447 m, 9 October 2011); ZMB 78504 (two tadpoles, Gosner stages 25 & 27, Caldera, 5°2’26.2”N, 9°48’30”E, 1889 m, 2 September 2011); ZMB 78505 (two tadpoles, Gosner stage 25 & 28, Caldera, 5°2’26.2”N, 9°48’30”E, 1889 m, 17 October 2011); ZMB 78507 (three tadpoles, Gosner stage 25, Manengouba village, 4°56’50.3”N, 9°52’45.8”E, 996 m, 28 June 2011); ZMB 78508–09 (six tadpoles and one tadpole, respectively, Gosner stage 25, M’Bouroukou, 5°3’48.2”N, 9°52’0.09”E, 1518 m, 22 September 2011); ZMB 78511 (one tadpole, Gosner stage 25, Nkack, 5°2’17.4”N, 9°46’27.3”E, 1466 m, 12 October 2011); ZMB 78513 (five tadpoles, Gosner stage 25, Pastoral Nkongsamba, 4°59’13.26”N 9° 52’45.9”E, 1459 m, 18 January 2011); ZMB 78514–16 (two tadpoles, eight tadpoles and six tadpoles, respectively; Gosner stages 25 & 26, Pastoral Nkongsamba, 4°58’47.1”N, 9°53’41.9”E, 1225 m, 29 September 2011). The tadpoles occurred in small to mid-sized rivers between 996 m and 1889 m altitude. These riverbanks were covered with forest and farmbush vegetation ( Fig. 2 ).

The description is based on ten genotyped tadpoles (ZMB 78500–01, 7850–304, 78507–09, 78511, 78513, 78515) at Gosner stage 25. Body length/total length ratio and description of tail tips was based on non-genotyped specimens of the same developmental stage.

Morphology. Long but robust tadpole with long tail and very broad muscular tail axis; body elliptical in dorsal and robust and pointed in lateral view ( Fig. 8 a, b); body length 28.3 ± 2.4% (N= 31) of total length; body height 42.2 ± 3.9% (N= 10) of body length; body width 54.0 ± 4.2% (N= 10) of body length, maximum body width on level of spiracle insertion; snout truncate to nearly rounded in dorsal view; nostrils oval and situated laterally; nostrils equidistant from eye and snout tip; eye diameter 12.7 ± 0.9% (N= 10) of body length; inter-orbital distance slightly smaller than inter-nostril; tail fins narrow; dorsal fin mostly originating posterior to tail base (exceptionally fin insertions at or slightly anterior to tail base were observed); narrow dorsal fins, reaching deepest point posterior to mid-tail, slightly deeper than ventral fin; ventral fin originates at level with tail base, runs almost parallel to tail axis; tail tip rounded; tail axis very broad and muscular in dorsal and lateral view; body height 91.0 ± 4.1% (N= 10) of total tail height; maximum height of tail axis 69.1 ± 5.9% (N= 9) of maximum tail height; vent tube dextral; lateral sacs present, extending from spiracle to end of body, covering lower two thirds of flanks; short sinister spiracle, translucent, opening lateral, not visible in dorsal view, originating at mid-body; mouth opening frontal; labial tooth row formula 0/0; both jaw sheaths completely keratinized; upper jaw narrow, almost rectangular, slightly bent, distinctly and uniformly serrated; lower jaw U-shaped, distinctly serrated with a lateral pair of caniniform projections (fangs), median part with six to seven needle-like cusps ( Fig. 8 d; Channing et al. 2012: 8); two distinct serrations abaxial to fangs; posterior lip huge semicircular to oval bean shaped, covered with 21 papillae ( Channing et al. 2012: 20); arrangement of papillae symmetric to vertical body axis; papillae arranged in two semicircular rows ( Fig. 8 c); straight to semicircular skin fold on lower lip, just posterior to lower jaw sheath; oral disc width 34.0 ± 2.6% (N= 10) of body length; mouth width 26.2 ± 3.2% (N= 10) of oral disc width.

The most advanced individuals (ZMB 78499, Gosner stage 40; ZMB 78500, three tadpoles of Gosner stages 40–42) measured 43.3–46.2 mm (body length. 11.3–13.9 mm; tail length: 29.7–32.6 mm). A few tadpoles of Gosner stages 25–26 even reached 46.1–49.5 mm total length. Channing et al. (2012) reported 52 mm total length. Amiet (1980) measured metamorphs, still possessing 4–5 mm tails, with 13.5–15.5 mm SVL.

Coloration in preservation. Pale brown body and tail; dorsal parts of body and entire tail axis heavily mottled with little dark spots; ventral parts lighter; fins with very few dark markings, translucent cream white; some individuals with cream-white snout.

Figures

FIGURE 2. Habitats of Leptodactylodon tadpoles; a: small forest fragment behind Manengouba-Village, habitat of L. mertensi and L. ornatus ornatus, Mt. Manengouba, N 4 ° 57 ' 12.6 " E 9 ° 51 ' 33.36 ", 1093 m; b: mountainous forest, habitat of L. erythrogaster, Mt. Manengouba, N 4 ° 57 ' 12.6 " E 9 ° 51 ' 33.36 ", 2100 m; c: strongly degraded farmbush area, habitat of L. bicolor, Mt. Manengouba, near Pola N 5 ° 3 ' 27.78 " E 9 ° 50 ' 8.88 ", 1742 m; d: small forest fragment between farms, habitat of L. mertensi, Mt. Manengouba, near Nkack, N 5 ° 0 ' 46.5 " E 9 ° 46 ' 5.82 ", 1372 m. The tadpoles were caught hiding under stones in river parts with little current.

FIGURE 8. Dorsal (a) and lateral view (b) of Leptodactylodon mertensi with sketches of the mouthpart in frontal view (c) and jaw sheaths with caniniform projections (d); scale bars: 1 mm.