A new fossil marten from Jinyuan Cave, northeastern China reveals the origin of the Holarctic marten group

Abstract Martes is one of the most widely spread genera and has the probably longest evolutionary history among the living Carnivora, yet its fossil record is incomplete, especially those related to the crown group of Martes. Here we describe a fossil species, Martes crassidens sp. nov. from the Jinyuan Cave, Luotuo Hill, Dalian Puwan Economic Zone, Liaoning Province in northeastern China. The materials were found from the lower deposits belonging to the early-middle Early Pleistocene. Our morphological comparison, morphometric and morphotype analyses suggest the fossil species shows a clear affinity to the Holarctic marten group (here referred to HMG), i.e. Martes, Martes zibellina, Martes melampus, Martes americana, in having robust dentition, enlarged P4 protocone and M1 inner lobe. It also has unique characters, e.g. relatively large body size, very robust carnassial, high crowned m1 and relatively short talonid, which is different from any living and known fossil species and probably suggests a durophagous dietary behavior. Martes crassidens represents so far the earliest record of the HMG, and provides evidence for the chronological framework of the crown marten diversification.