Do larger cephalopods live longer? Effects of temperature and phylogeny oninterspecific comparisons of age and size at maturity

The relationship between size and age at maturity in cephalopods is unresol ved. The most recent interspecific comparison of size and age of cephalopod s contradicts two previous studies by concluding that larger species do not live longer. This paper addresses the confounding effects of temperature a nd phylogeny while answering the question, "Do larger cephalopods live long er?". To test this hypothesis, life-history data from 18 species of cephalo pods, from five orders, with sizes at maturity spanning five orders of magn itude, were obtained from the literature. Without temperature consideration and with Nautilus spp. included in the sample, regression analysis suggest s (r(2) = 0.376, p = 0.007) that larger cephalopods take longer to reach ma turity. Once temperature was controlled by using physiological time (degree -days), the coleoid cephalopods moved closer to the best fit line and the g enus Nautilus became an outlier. When Nautilus was removed and time measure d in degree-days, the relationship was very strong (r(2) = 0.785, p < 0.001 ). We conclude that coleoid cephalopods achieve larger size by delaying mat urity and that temperature, as well as phylogeny, must be considered when m aking interspecific comparisons.