Astylosternus perreti Amiet, 1978

Griesbaum, Frederic, Hirschfeld, Mareike, F. Barej, Michael, Schmitz, Andreas, Rohrmoser, Mariam, Dahmen, Matthias, Muehlberger, Fabian, Christoph Liedtke, H., L. Gonwouo, Nono, Doumbia, Joseph & Roedel, Mark-Oliver, 2019, Tadpoles of three western African frog genera: Astylosternus Werner, 1898, Nyctibates Boulenger, 1904, and Scotobleps Boulenger, 1900 (Amphibia, Anura, Arthroleptidae), Zoosystematics and Evolution 95 (1), pp. 133-160 : 143-144

Astylosternus perreti Amiet, 1978

Material examined.

ZMB 82877 (GenBank MK318864), Gosner stage 25, Cameroon, Mt Manengouba, Ebonemin, 1365 m, 5°0'33"N, 9°46'30"E, 14 December 2010, leg. M. Hirschfeld; ZMB 82879 (GenBank MK318865), Gosner stage 25, Cameroon, Mt Manengouba, Ebonemin, 1372 m, 5°0'46.5"N, 9°46'5.82"E, 16 December 2010, leg. M. Hirschfeld; ZMB 82880 (GenBank MK318866), Gosner stage 25, Cameroon, Mt Manengouba, near Pastoral Nkongsamba, 1457 m, 4°59'13.26"N, 9°52'45.9"E, 18 January 2011, leg. M. Hirschfeld & F. Grözinger; ZMB 82881 (GenBank MK318867), 2 tadpoles, 1 genotyped, both Gosner stage 25, Cameroon, Mt Manengouba, Ebonemin, 1356 m, 5°1'33.4"N, 9°45'46.7"E, 16 August 2011, leg. M. Hirschfeld; ZMB 82882 (GenBank MK318868), Gosner stage 25, Cameroon, Mt Manengouba, Ebonemin, 1372 m, 5°0'46.45"N, 9°46'5.82"E, 7 October 2011, leg. M. Hirschfeld; ZMB 82883 (GenBank MK318869), 2 tadpoles, 1 genotyped, both Gosner stage 25, Cameroon, Mt Manengouba, Ebonemin, 1372 m, 5°0'46.5"N, 9°46'5.8"E, 7 October 2011, leg. M. Hirschfeld; ZMB 82884A, Gosner stage 28, ZMB 82884B (GenBank MK318870), Gosner stage 27, Cameroon, Mt Manengouba, Ebonemin, 1342 m, 5°0'46.5"N, 9°46'30.9"E, 8 October 2011, leg. M. Hirschfeld; ZMB 82816 (GenBank MK318871), Gosner stage 26, Cameroon, Mt Manengouba, Ebonemin, 1356 m, 5°1'33.42"N, 9°45'46.74"E, 13 December 2010, leg. M. Hirschfeld.

All tadpoles were caught in small to medium-sized streams and rivers in secondary and very degraded forests. The description is mainly based on ZMB 82881B and ZMB 82884B. Genotyped tadpoles have been compared with an adult from Mount Kupe, Cameroon (MHNG 2715.38; GenBank MK318872). The uncorrected pairwise p-difference between tadpoles and between tadpoles and the adult ranged from 0-0.4% (0-2 bp).

Description.

Long slender tadpole with strong and muscular tail (Fig. 12); longish oval in dorsal view, slightly flatter in lateral view; back with medial, longitudinal depression; snout broadly rounded in dorsal view, more narrowly rounded in lateral view; body length 31.2 ± 2.2% of total length; body height 43.4 ± 4.5% of body length; body width 54.7 ± 5.9% of body length; eyes positioned dorsolaterally, eye diameter 12.0 ± 1.5% of body length; nostrils positioned dorsolaterally, closer to snout tip than to eyes; inter-nostril distance 87.7 ± 5.1% of interorbital distance; tail fins narrow; dorsal and ventral fin originating from tail base; ventral fin height 79.9 ± 6.8% of dorsal fin height; highest part of tail approximately in the middle of the tail; body height 98.8 ± 11.2% of maximum tail height; tail axis width 48.5 ± 10.3% of body width; tail axis height 72.3 ± 7.3% of maximum tail height; tail tip very narrow, filamentous; vent tube dextral; body with large lateral sacs, extending from spiracle to end of body; short spiracle, sinistral; mouth ventral, near snout and narrower than interorbital distance; keratodont formula 1:2+2/2+2:1; anterior lip with only a few lateral papillae and large rostral gap; posterior lip with 2 or 3 rows of ca 20-30 small, broadly triangular (shark tooth-shaped) papillae (Fig. 12c), medial papillae bigger than lateral ones; black, massive, serrated jaw sheaths; upper jaw broadly arched with a small medial projection (fang), lower jaw narrow U- to V-shaped.

The largest tadpole in Gosner stage 25 measured 26.2 mm body length and had an approximate total length of 78 mm. The most advanced specimen at Gosner stage 28 had a total length of 108.1 mm.

Coloration in preservation.

Body dark brown; tail very light brown to beige; lateral sacs and ventrum lighter brown or dark gray; a broad dark brown longitudinal band on tail axis reaching about middle to two-thirds of tail length, proximate end of tail with smaller dark speckles; fins light yellowish beige (Fig. 12). In life body and tail light brown with black blotches on back and broad black bands and spots on tail axis; lateral sacks light grayish brown; tail fins transparent greyish brown (Fig. 13).

Variation.

In larger specimens (Fig. 12b, c) the dark pattern on body and tail axis seems to fade, base color becomes darker. Size and arrangement of dark marks differ between specimens (Figs 12b, c, 13).

Taxonomic remarks.

Whereas all genotyped tadpoles and the comparative adult were genetically almost identical, a single specimen (MHNG 2715.40 from Mofako Balue, Rumpi Hills) differed genetically by about 2%, indicating intraspecific genetic variability or cryptic diversity. The tadpoles used for the description are from the area of the type locality (Mouandong) of A. perreti .