Answer 1:
Semicossyphus pulcher previously held the
scientific name of Pimelometopon pulchrum. I was not able to determine the meaning of either name.
Specific epithets (the species names) are usually meaningless because they can be the name of someone's dog or their favorite beverage. The
Genus name is usually better to analyze.
As far as the trophic position of the sheephead, the fish is a large predator (up to 16 kg) and is considered to be fairly high up the food chain in reef/kelp ecosystems. These fish eat hard-shelled organisms such as sea urchins, mollusks, lobsters and crabs. These organisms differ in their trophic
status, as urchins and mollusks can eat plant
matter while lobsters and crabs eat mainly
animals. If we consider a classical food chain,
from plants, to herbivores, to primary consumers,
to secondary consumers (an example would be a
plant eaten by an insect eaten by a lizard eaten
by a hawk) the sheephead probably falls somewhere
between a primary and secondary consumer as its
trophic position, because it feeds both on
herbivores and on primary consumers.
The "job" of a sheephead is complex. The best way to think about this is to see what would happen if we took sheepheads away from the kelp ecosystem.
Sheepheads can live up to 50 years, and grow
slowly, so over their lifetimes they likely
consume many prey. Depending on how many sheephead
are present in a kelp ecosystem, they probably
control the population growth of their prey, such as urchins and crabs. This is an important job: We know that if many of the organisms which eat urchins are lost from a kelp forest, the urchins will grow out of control and eat all the kelp, which can reduce or eliminate many forest species.
In addition, sheepheads are eaten by seals and sea lions. | 
