Differences in larval survival and development among three Chilean decapods are consistent with their southern range limits

In marine organisms with complex life cycles, the planktonic larval stage is among the most sensitive to environmental variation, affecting dispersal potential in early life. We compared larval mortality and development at 10, 13, 16, and 19 °C among three Chilean decapods with contrasting southern range limits: the brachyuran crabs Cancer porteri (38°S) and Metacarcinus edwardsii (55°S), and the anomuran Petrolisthes violaceus (46°S). Metacarcinus edwardsii completed development across the full range, whereas C. porteri presented complete mortality in zoea III at 10 °C and in zoea V at 13 °C, and P. violaceus had complete mortality in zoea I at 10 °C, with partial survival to the megalopa at 13 °C. Development in M. edwardsii was less affected at low temperatures. At the cold end of the range, the probability of reaching the megalopa followed southern range limits, although spring sea temperatures near those limits were lower than the temperatures that constrained development in our cultures. Laboratory values therefore indicate a relative ordering among species rather than the temperatures that set a range edge. This consistency between larval performance and geographic distribution suggests that early-life thermal constraints may contribute to biogeographic patterns along the Chilean coast.