Molecular clocks indicate turnover and diversification of modern coleoid cephalopods during the Mesozoic Marine Revolution

Coleoid cephalopod molluscs comprise squid, cuttlefish and octopuses, and represent nearly the entire diversity of modern cephalopods. Sophisticated adaptations such as the use of colour for camouflage and communication, jet propulsion and the ink sac highlight the unique nature of the group. Despite these striking adaptations, there are clear parallels in ecology between coleoids and bony fishes. The coleoid fossil record is limited, however, hindering confident analysis of the tempo and pattern of their evolution. Here we use a molecular dataset (180 genes, approx. 36 000 amino acids) of 26 cephalopod species to explore the phylogeny and timing of cephalopod evolution. We show that crown cephalopods diverged in the Silurian–Devonian, while crown coleoids had origins in the latest Palaeozoic. While the deep-sea vampire squid and dumbo octopuses have ancient origins extending to the Early Mesozoic Era, 242 ± 38 Ma, incirrate octopuses and the decabrachian coleoids (10-armed squid) diver...

鞘亚纲头足类软体动物（coleoid cephalopod molluscs）包含鱿鱼、乌贼与章鱼，几乎涵盖了现代头足类的全部物种多样性。诸如用于伪装与通讯的体色调控、喷水推进机制以及墨囊等复杂适应性特征，凸显了该类群的独特性。尽管具备这些极具特色的适应性特征，鞘亚纲头足类与硬骨鱼类的生态特征仍存在清晰的相似性。然而鞘亚纲头足类的化石记录较为匮乏，这阻碍了对其演化速率与演化模式的精准分析。本研究基于涵盖26种头足类的分子数据集（包含180个基因，约36000个氨基酸位点），探究头足类的系统发育关系与演化时间线。研究结果表明，冠群头足类（crown cephalopods）的分化发生于志留纪至泥盆纪时期，而冠群鞘亚纲头足类的起源则可追溯至古生代末期。尽管深海吸血鬼乌贼（vampire squid）与小飞象章鱼（dumbo octopuses）的起源可追溯至距今242±38百万年前的中生代早期，无触须章鱼（incirrate octopuses）与十腕鞘亚纲头足类（decabrachian coleoids，10腕鱿鱼）的分化则...