Annelid Allies Flashcards
annelid affinities
- Pogonophora (Siboglinidae)
- Echiura
Molluscan affinities
Sipuncula
Pseudocoelomates affinities
Priapulida
(most similar to Ecdysozoa (Nematoda, Nematomorpha, Kinoryhncha and Loricifera))
molts any may have pseudocoel
Shared characteristics
- vermiform
- hydrostatic skeleton
- unsegmented (except Siboglinidae)
- used to be lumped into one phylum
adaptive zones
Priapulida- marine burrowers, some interstitial, some tubiculous
Sipuncula- marine burrowers, some bore into coral, deposit feeders
Echiura- marine burrowers, filter+deposit feeding
Pogonophora- deep sea, tube building, symbiosis w/ chemoautotrophic bacteria
tubicolous
(of a marine worm) living in a tube
meiofauna
minute interstitial animals living in soil and aquatic sediments
Priapulida characteristics
$-Cambrian fossil (1500 specimens) >> Phylum $-coelum or pseudocoel $-molts $-through gut -separate sexes $-spiny proboscis -no circulatory system, respiratory pigment Hemerythrin -planktonic larvae $-tail-like appendage
Sipuncula characteristics
- first fossil most likely Cambrian»_space; Phylum
-protostome
-cilliary photorecepters near mouth
-coelum
$-trochophore larvae (characteristic of most mollusks) can become pelagosphaera larvae (unique to sipuncula)
$- can develop directly, can go through troch. larva stage, or troch. and pelago. stages
-separate sexes
$-urn cells
-U shaped gut (like gastropoda?)
$-introvert w/ tentacles
-ventral nerve
Trochophore larva
top shaped cilliated larva
-Most mollusks, most marine annelids, Entoproctoa, Sipuncula, and Echiura
Echiura Characteristics
$-annelid class $-earliest fossil Pennsylvanian >> class $-"in-keeper" worm, burrow w/ symbionts -proboscis -through gut -open circulatory system with hemoglobin -setae -trochophore larvae -separate sexes -ventral nerve
Pogonophora- Siboglinidae characteristics
$-posterior segmentation
- deuterostomes, but gut lost in adults
- few cm to a few m
- spiral cleavage
- ventral nerve cord, ganglia
- closed circulatory system, hemoglobin
- separate sexes
- body sections sepatarted by septa
- coelomate
- rare fossils