Embryonic and Larval Development of the Sunset Frog, Spicospina flammocaerulea (Anura: Myobatrachidae), from Southwestern Australia

Abstract 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.