Embryonic development of the myobatrachine frogs Geocrinia laevis, Geocrinia victoriana, and their natural hybrids

Abstract

The Australian frogs Geocrinia laevis and Geocrinia victoriana undergo prolonged embryonic development inside their egg capsules, before hatching as advanced tadpoles. Despite the presence of large amounts of yolk, the course of development follows the typical anuran pattern rather closely, and is essentially identical in the two species and their natural hybrids. We present a modification of Gosner's (1960) staging table, using mainly changes in the eye and the mouthparts to define stages (20 to 26) in a phase of development, when the Gosner table is not applicable to myobatrachine frogs.

Phenotypic differences in terrestrial frog embryos: effect of water potential and phase

“…Egg clutches were collected over a 10 day period and thereafter containers were continuously sealed ensuring ψ v was undisturbed. After 47 days of incubation the oldest embryos reached hatching stage 26 (Gollmann and Gollmann, 1991) and were removed for measurement of morphological traits and rate of oxygen consumption (V O 2). Removal of embryos from the remaining clutches occurred over the next 10 days when each clutch was 47 days old.…”

A comparative study of divergent embryonic and larval development in the Australian frog genus Geocrinia (Anura: Myobatrachidae)

“…The mean number of eggs in 20 egg masses from Kinglake West (Littlejohn and Martin 1964) was 121 (90-162). Early development has been well documented by Littlejohn and Martin (1964), Martin and Cooper (1972) and Gollmann and Gollmann (1991a). The mean diameters of ova prior to stage 10 vary from 3.1 mm at Kinglake West (Littlejohn and Martin 1964) to 1.9 mm (at Gellibrand; Gollmann and Gollmann 1996b), the latter nearer to the hybrid zone with G. laevis.…”

“…In this table, Gosner (1960) stages (indicative of hind limb development only) are given in parenthesis to assist comparison with the Gosner limb development stages in the exotrophic Geocrinia species. For the exotrophic species, stages in Appendix 2 are those of Gosner (1960) and incorporate features for stages 20-26 of Gollmann and Gollmann (1991a).…”

“…Stages 20-26 of Gollmann and Gollmann (1991a) devised to suit these early development stages of the eastern G. laevis and G. victoriana are incorporated here for G. leai as well (Appendix 2).…”

“…Various descriptions of the embryonic and larval development of the two eastern exotrophic species have been published (Littlejohn and Martin 1964;Martin 1967;Littlejohn et al 1971;Watson and Martin 1973;Martin and Littlejohn 1982;Gollmann and Gollmann 1991a,b, 1992a,b, 1993, 1996aAnstis 2002). For the southwestern species, there are studies including some developmental descriptions of G. leai and G. rosea by Main (1957Main ( , 1965 and of G. vitellina by Mitchell (2001).…”