Rubicundus is a genus of hagfishes, the only extant member of the subfamilyRubicundinae. All species in it were formerly classified in Eptatretus. R. eos, R. lakeside, and R. rubicundus are known from single specimens caught in the Tasman Sea, Galápagos, and Taiwan, respectively. They are named after the distinctive red coloration that all species share.[2]
They represent the sister lineage to all other extant lineages of hagfishes, and may represent the sister group to the Cretaceous fossil hagfish Tethymyxine, from which they potentially diverged during the Late Jurassic or Early Cretaceous. Both Rubicundus and Tethymyxine share an elongate snout, indented barbels, and numerous slime glands.[3] Phylogenetic studies indicate that the Rubicundinae lineage may have diverged from other extant hagfishes during the Permian, making them an extremely old lineage.[4]
Species
Four recognized species are placed in this genus:[5][6]
^Fernholm, B., Norén, M., Kullander, S.O., Quattrini, A.M., Zintzen, V., Roberts, C.D., Mok, H.-K. & Kuo, C.-H. (2013): Hagfish phylogeny and taxonomy, with description of the new genus Rubicundus (Craniata, Myxinidae). Journal of Zoological Systematics and Evolutionary Research, 51 (4): 296–307.
