a tapering profile that possibly merges into the base of a thick tail and with short, curved limbs splayed out to the side.

and并列了profile的二个后置定语。其中一个是定语从句，一个是with复合结构。虽然that从句和with复合结构在结构上不对等，但它们都是profile的定语，功能相同，所以用并列连词and并列。其实with复合结构可以改为定语从句， a tapering profile that possibly merges into the base of a thick tail and with short,curved limbs splayed out to the side.同样的意义：

 a tapering profile that possibly merges into the base of a thick tail and which has short, curved limbs splayed out to the side.
一个逐渐变细的轮廓可能与一条粗尾巴的根部融合，其侧方有短而弯曲的肢体向外伸出。