Front Physiol. 2018 Dec 18;9:1833. doi:10.3389/fphys.2018.01833

Zhang QL, Zhang GL, Yuan ML, Dong ZX, Li HW, Guo J, Wang F, Deng XY, Chen JY, Lin LB.

A Phylogenomic Framework and Divergence History of Cephalochordata Amphioxus.

Supports “a phylogeny of [(B. belcheri + B. japonicum) + (B. lanceolatum + B. floridae) + Asymmetron lucayanum] in amphioxus”. Estimates that “the most recent common ancestor of the living amphioxus species (the divergence time between Asymmetron and Branchiostoma) was estimated to be ∼104 Mya [23.74—211.63]; the early splits within each main clade occurred at ∼87 Mya [41.02—162.19]; B. lanceolatum diverged from B. floridae at ∼72 Mya [31.93—149.68], and the divergence time between B. belcheri and B. japonicum was ∼61 Mya [10.21—136.41]”.