The latest study resolves a debate about whether it is the first member of the chordate family .
这个最新的研究终结了一场关于它是否是脊椎动物家族中第一个成员的争论。
Dean 's area of expertise is conodonts , an obscure group of microfossils thought to have been an extinct animal called the chordate - which , judging from the pictures , looked a bit like a worm .
