EEMB 136L Lecture 11: Lab 11
15 Nov 2017
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Document Summary
An extinct group that flourished in the paleozoic. Like ostacodes, it has mineralized exoskeletons and lived in exclusively aquatic habitats-> more preserved fossil records. Bilateral symmetry with a segmentation (body divided into specialized regions called tamata) Hard exoskeleton (jointed cuticle) for support and protection from predators/ dehydration. Ecdysis: growth by shedding the exoskeleton and secreting a larger one. 2 pairs of antennae in front of mouth and 1 pair of mandibles behind the mouth a. Have cuticles that are reinforced with calcium carbonate -> good fossil record iii. b. Larvae mobile, but become sedentary as adults by attaching themselves to a substrate head-first, and then forming a calcareous shell around their bodies, using their legs for filter feeding. c. Secrete 2 calcareous shells that completely encase body. Benthic filter feeders have significantly reduced bodies with two pairs of antennae, two pairs of mouthpart appendages, three pairs of leg-like thoracic appendages, and a pair of furcal claws vi. d.
