Tadpoles collected at two distinct sites in the ditch near Yesod HaMa’ala on 15 May 2015 agree with the description of Mendelssohn and Steinitz (1943) in having double keratodont rows and a network of black epidermal lines. They were small (total length 14 mm at Gosner stage 25 and 24 mm at Gosner stage 34), uniformly brown, with an unpigmented ventral side and ventral spiracle. The LTRF was 2/3(1), not considering double rows (Fig. 7). For a detailed description of the tadpoles see Appendix 3, for raw measurements see S5 in the Supplement.
The tadpoles of L. nigriventer are distinguished from those of the three other anuran species in this area (Bufotes variabilis (Pallas, 1769), H. savignyi and P. bedriagae) as well as those of Pelobates syriacus Boettger, 1889, by their medial ventral spiracle, distinct epidermal reticulations and double keratodont rows. Such biserial rows of keratodonts are a unique state for the basal anuran genera Discoglossus and Ascaphus, and are, with exception of Hoplobatrachus, not found in more advanced frogs (Grosjean et al., 2004). Dorsally, L. nigriventer tadpoles mostly resemble the ones of Bufotes in the position of their eyes and general appearance, but they lack the distinctly golden speckled venter as observed in the latter. The unpigmented venter of L. nigriventer tadpoles likewise serves as an immediate distinguishing characteristic from both Hyla and Pelophylax tadpoles that display a silvery venter.
Of the 40 tadpoles (Gosner stages roughly between 25 and 35) found on 15 May, 9 were successfully raised to post-metamorphs at the School of Marine Sciences (Ruppin Academic Center), Michmoret, where metamorphosis took place between 3–15 June 2015. Recently metamorphosed frogs had a SVL of 6–9 mm. At the end of June, all post-metamorphs were transferred to the Garden of Zoological Research at Tel Aviv University for further rearing.