What is "spriggina"

Fossils of Spriggina are known from the Ediacaran period, around . The segmented organism reached about 3–5 cm in length and may have been predatory. Its bottom is covered with two rows of tough interlocking plates, while one row covered its top; its front few segments fused to form a "head", which may have borne eyes and antennae.

Spriggina's affinity is currently unknown; it has been classified as an annelid worm, a rangeomorph-like frond, Proarticulata, and/or an arthropod, perhaps related to the trilobites. Lack of known segmented legs or limbs, and glide reflection instead of symmetric segments, suggest an arthropod classification is premature despite some superficial resemblance.