- generally large trilobites
- had a lot of pleura which means they have the ability to enroll for protection - lots of legs 1 pleura = 2 legs
- epifaulnal - they crawl on the sea floor looking for food as active hunters or scavengers
- had very good eyes 360* vision, the eyes would have been sensitive to movement to detect food and predators an advantage over other bottom dwellers in the same enviroment- could explain why they where so successfull.
Pelagic (e.g. Agnostus)
They where blind as no eyes
- had few pleura, and therefore few legs or gills.
- found in sediments such as shales formed in low energy deep waters
- had a pelagic planktonic lifestyle
- possible lack of eyes means in deep water where theres no light
- they where small and probably light weight
Nektonic (e.g. Deiphon)
- These where small trilobites - to stay a float
- show streamlining
- actively swimming, possibly as active hunters
- eyes on stalks- ability to see 360* and beneth
- inflated glabella may be filled with fat org as to help to float
- has lots of pleura , with spines - has many legs for swimming and spines to increase surface area
Burrowing (e.g. Trinucleus)
- These trilobites lack eyes
- shovel like head
- benthonic and infaunal
- no eyes due to depth
- dug shallow burrows for protection or to feed
- extended genal spines - to spread its mass on soft substrate
- pitted cephalic fringe
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