Download 1 The Lophophorate Phyla Lophophorate Characteristics

The Lophophorate Phyla
Lophotrochozoa
Lophophorata
Lophophorate Characteristics
=“crest bearers”
phoronids, brachiopods, ectoprocts
(bryozoa), entoprocts (kampozoa)
at first members have little in
common
allied with deuterostomes =
tripartite body plan (pro-, meso-,
metasome)
each part contains a separate
coelom
U-shaped gut, often transient
reproductive
nearly all secrete casings/shells
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Phylum Phoronida
=“horseshoe worms”
20 species, 2 genera (Phoronis,
Phoronopsis)
0.6-50cm long, 5mm thick
entirely marine
vermiform body enclosed in chitinous
tube
sedentary, infaunal, benthic
intertidal - 400m
Lifespan = up to a year
lophophore = 1-many 100s tentacles
suspension feeders = lophophore into
current
Phoronid Distribution
Phoronid Bauplan
prosome (protocoelom) =
epistome = fold extending
along tentacles, overhanging
mouth
mesosome (mesocoelom) bears
lophophore, diaphragm
metasome (trunk, metacoelom)
= slender, cylindrical, posterior
ampulla
NS= ganglion b/w mouth-anus,
nerve ring (lophophore) & giant
nerve fibers
metanephridia
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Phoronid Bauplan continued
Closed circulation, 2 longitudinal
vessels, stomach blood plexus,
erythrocytes
Phoronid Reproduction
hermaphrodites
fertilization likely internal
2 strategies:
1. few, large eggs (12-25), yolk,
brooded
2. large # of small eggs (500),
hatch after days
larvae = actinotroch,
planktotrophic for 2-3 weeks
metamorphosis = catastrophic
(30 min)
asexual through regeneration
Phylum Ectoprocta (Bryozoa)
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Bryozoan Characteristic
= “moss animals”, sessile,
colonial
5000 known species
marine, freshwater (50 species)
less than 0.5 cm
each colony lives inside a
chamber
antineoplasic reagents = Bugula
= Bryostatin
Bryozoan Bauplan
colony = zoarium
zooid = 1 animal
exoskeleton =
zoecium
polyp(ide) =
lophophore & soft
body
orifice = opening
operculum =
flaplike covering
Bryozoan Bauplan
Nature of exoskeleton/ form of colony differs
Forms are either lophopodid or plumatellid
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Bryozoan Bauplan
Colony forms can be categorized as stoloniferous
or nonstoloniferous
Bryozoan Bauplan
Zooids in many colonies are polymorhpic
autozooids
heterozooids
kenozoids
avicularia
Bryozoan Bauplan
lophophore can be retracted in
membranous sac = dilator
muscles
atrium closure = sphincter
muscles
ciliary tracts in tentacles =
current towards mouth
http://bryozoa.blogspot.com/2007/11/ecology.html
U-shaped digestive tract
brown bodies = waste elimination
NS and sense organs reduced
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Bryozoan Reproduction
Asexual
budding = colony expansion
Sexual
hermaphrodites
external fertilization, some
brood (ovicells)
larvae of free = feed, larvae of
brooding = no feeding
commonly cyphonaute larva
Phylum Entoprocta
Entoprocta Characteristics
= goblet worms, nodding heads,
kamptozoans
0.5-5mm in size,
150 species
aquatic, mostly marine
speculated to be related to
bryozoans, but pseudocoelomate
superficially resemble Hydra polyp
sequential hermaphrodites
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Entoprocta Bauplan
goblet shaped and bilaterally symmetrical
6-36 tentacles around mouth/anus, fold over mouth
contractile stalk attaches to substrate
no muscle layers, circulatory or gas exchange organs
Phylum Brachiopoda
Brachiopoda Characteristics
solitary, benthic, marine, 2shelled, attach to substrate
by pedicle
most 4-6cm but range from
1mm-9cm
335 living species
= rare today, dominant during
Paleozoic
incredibly rich fossil record
outcompeted
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Brachiopod Bauplan
ventral/pedicle valve
= animals ventral side up
dorsal/brachial valve
outer shell = periostracum
inner = variable substances
=> secreted by mantle lobes
many shells with
perforations = punctate
articulated by adductor
muscles
reduced NS= dorsal/ventral
ganglion
ciliated lophophore
Brachiopod Reproduction
no asexual reproduction (similar to
bivalves)
diecious, gonad transient in
metacoel
fertilization external
some brood (sperm picked up by
female feeding current)
cleavage = holoblastic, radial and
leads to coeloblastula
lobate larva
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