Image caption: A dwarf crocodile. (C) Jim Frazee
Because the model we use to explain sex determination in crocodiles cannot help explain this evidence, we must keep asking questions and build better models for looking at our evidence.
Langer: Half of the 22 extant species of crocodilians have been examined for occurrence of temperature dependent sex determination (TSD). In TSD reptiles, masculinizing temperatures yield 100% or a majority of males, whereas feminizing temperatures yield 100% or a majority of females. In the transition range of temperature (TRT), a mix of males, females and sometimes intersexes are obtained. However, the molecular mechanisms behind TSD and an explanation for the occurrence of intersexuality remain elusive.
References
C. Johnston, M. Barnett, and P. Sharpe, 1995, The molecular biology of temperature-dependent sex determination, Phil. Trans. R. Soc. Lond., ser. B, 350: 297-304.
J.W. Lang and H. Andrews, 1994, Temperature-dependent sex determination in crocodilians, J. Exp. Zool. 270-28-44.
S. Langer, K. Ternes, D. Widmer, & Frank Mutschmann. The first case of intersexuality in an African dwarf crocodile (Osteolaemus tetraspis). Zoo Biol. 33:459–462, 2014. DOI:10.1002/zoo.21149
C. Smith and J. Joss, 1993, Gonadal sex differentiation in Alligator mississippiensis, a species with temperature-dependent sex determination, Cell Tissue Res. 273:149-62.
Wibbles, Bull, and Crews, 1994, Temperature-dependent sex determination. Journal of Experimental Zoology 270(1):71 - 78. DOI: 10.1002/jez.1402700108