关键词: 真牙形石, 脊椎动物, 牙本质, 比较组织学

Abstract: The hypothesis that conodonts are vertebrates has been supported by the evidence of the microstructural, topological and developmental homology of hard tissues between conodonts and vertebrates. However, this conclusion was based on the evidence from some highly derived euconodont taxa; the degree of their plesimophic to basal euconodonts still remains in question. By employing the oil-immension techniques, the authors observed tubular and atubular (parallel-and wavy-lamellar) dentine in the basal bodies of the most primitive euconodont Proconodontus tenuiserratus Miller, 1980 and Proconodontus muelleri Miller, 1969, respectively. The tubular dentine is also recognized from Granatodontus ani (Wang, 1985). Because these data represent the earliest euconodonts, these new histological data can be treated as the plesiomorphic feature of the basal euconodonts, strongly supporting that euconodonts have tight affinity with vertebrates.

Key words: euconodont, vertebrate, dentine, comparative histology