a) Hallucigenia Sparsa is a now extinct
Middle Cambrian libopodian.
structure: H. sparsa varied from 0.5 to 3cm in length. They had
a pair of eyes on top of their head. Beneath their head was a long neck,
connecting to its tubular body. Below the body was 10 pairs of appendages. On
top of the body was 7 pairs of spines (Yeager, 2015). The mouth was of circular
shape and the stomach lined with acicular teeth (Smith & Caron, 2105).
There is a tubular, tail-like extension at the end of the body following the
Protection: The seven
pairs of hard spines on top of the body protected it from predation, as well as
the appendages which provided manoeuvrability
Carnivorous. S. Conway Morris (1976) suggests that they were scavengers,
gathering to feed on already dead prey and that they probably mainly grazed on
immobile organisms such as marine sponges.
lived in a marine environment, and it’s tentacle-like limbs acted as legs
assisted in moving around the seafloor.
b) H. sparsa’s
ability to escape from predators played a huge role in its survival success in
the beginning of the Cambrian explosion. It was able to pace the ocean floor
using its appendages with and against currents, advantageous in the event of
being hunted. Its spikes would have also produced great advantages in
protection against predators unlike other soft-bodied worms such as relatives
of the Hallucigenia. In addition to
this, H. Sparsa were amongst the earlier organisms to evolve hard body parts so
this would have aided its succession in comparison to other soft-bodied organisms.
sparsa is now extinct, with arthropods as modern day living relatives. The
closest living relative to H. sparsa is the velvet worm. Both species share the
ability of growing a new set of claws before they shed their skins in order to
grow. H. sparsa had this trait in their claws and the velvet worm has this in
both their claws and jaws. Although lacking the teeth lining within the
stomach, velvet worms similarly have paired limbs also used for manoeuvrability
(Oliveira & Mayer, 2013).