Embryonic and Larval Development of the Sunset Frog, Spicospina flammocaerulea (Anura: Myobatrachidae), from Southwestern Australia
The eggs, embryos, and tadpoles of Spicospina flammocaerulea are described. The free-swimming tadpole has a distinctive body form among described Australian genera but shares morphological similarities with the myobatrachid genera Taudactylus and Uperoleia. The egg capsules have an unusual semiopaque outer envelope that is similar to a firm gelatinous envelope present on egg capsules of some species of Uperoleia. The embryos are unique among described Australian genera in that they do not develop visible adhesive organs. Spicospina and Taudactylus and some Uperoleia larvae share a narial flap. Both Spicospina and Uperoleia have large nares that open in a dorsal direction. Larvae of S. flammocaerulea can be readily distinguished from other sympatric species by a combination of features of the oral disc and nares, position of the spiracle and eyes, and the low tail fins.Abstract
Embryos, hatchlings, and tadpoles of Spicospina flammocaerulea. Note scale bar differences: scale bars between A and B, C and D = 1 mm; between E and F = 1 mm; between G and H = 5 mm. (A) Stage 9, note gelatinous envelope. (B) Stage 9 with envelope peeled back. (C) Stage 18 lateral view. (D) Stage 18 dorsal view. (E) Stage 20, note that there are no adhesive organs. (F) Stage 22. (G) Lateral view, tadpole at stage 29: note the narial flap, low fins with no distinct arch, the position of the spiracle two-thirds along length of body and above horizontal body axis and the fine melanophores dermally and subdermally, on the spiracle and limb buds, and the clusters of melanophores on the dorsal surface and the dorsal tail fin. (H) Dorsal view, tadpole at stage 29: note the dorsal nares with narial flap, dorsolateral eyes and again the fine melanophores dermally and subdermally and the clusters of melanophores on the dorsal surface and the dorsal tail fin
Oral disc of Spicospina flammocaerulea. Scale bar = 1 mm. Note the downward directed flaplike fold across the anterior margin, and LTRF of 1/3(1)
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(Mad) School of Animal Biology (M092), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 Australia; and (MA) 26 Wideview Road, Berowra Heghts, New South Wales 2082 Australia. E-mail: (MAD) mdzimins@cyllene.uwa.edu.au Send reprint requests to MAD.