Wiwaxia is a genus of soft-bodied animals that were covered in carbonaceous scales and spines that protected it from predators. Wiwaxia fossils - mainly isolated scales, but sometimes complete, articulated fossils - are known from early Cambrian and middle Cambrian fossil deposits across the globe.[4][6][7] The living animal would have measured up to 5 cm (2 inch) when fully grown, although a range of juvenile specimens are known, the smallest being 2 millimetres (0.079 in) long.[7]
Wiwaxia's affinity has been a matter of debate: Researchers were long split between two possibilities. On the one hand, its rows of scales looked superficially similar to certain scale worms (annelids); conversely, its mouthparts and general morphology suggested a relationship to the shell-less molluscs. More recently, evidence for a molluscan affinity has been accumulating, based on new details of Wiwaxia's mouthparts, scales, and growth history.[7][8]
The proposed clade Halwaxiida contains Wiwaxia as well as several similar Cambrian animals.
Негізгі бет Ғылым және технология Wiwaxia Tribute
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