New evidence charaterizing TSD in Broad-snouted Caiman

PARACHÚ MARCÓ, M. V.; LEIVA, P.; IUGMAN, J.; SIMONCINI, M.; PIÑA, C. I.

Herpetological Conservation and Biology

HerpConBio

Año: 2017

1931-7603

Temperature-dependent sex determination (TSD) occurs in all three families of the Crocodylia.  This study explored the sex ratio of hatchlings under incubationtemperatures not previously tested in Caimanlatirostris to delineate the transitional range of temperature (TRT)between male- and female-producing temperatures.  We also estimated the pivotal temperature (Tpiv)of C. latirostris in our study site.  Eggs were incubated at various temperatures(31, 32, 33 and 34°C).   Incubationtemperature had a significant effect on sex determination, but had no effect inhatching success.  Eggs incubated at 31°Cproduced 100% females, 32°C produced approximately 70% females, and incubationat 33°C and 34°C produced only males.  TheTRT was >31°C to <33°C for female to male transitions, and >34°C and atemperature higher than 34.5°C male to female. Resultsindicate that the limits of Tpiv should be between 32 - 33°C (lowerTpiv), and between 34 - 34.5°C (upper Tpiv) for thepopulation of C. latirostris in SantaFe, Argentina.  Our analysis support the female-male-female (FMF) pattern but higher temperature femalesmay be rarely seen in wild since survival of females incubated at such hightemperatures is very low.