Lophotrochozoa “Minor Lophotrochozoa “Minor Phyla”Phyla”

Ecdysozoa: Onychophora, Tardigrada, Arthropoda, Nematoda, Nematomorpha,Kinorhyncha, Loricifera, Priapulida

Gastrotricha

Cuticulata

Protostomia

Lophotrochozoa

Eutrochozoa: Rotifera, Acanthocephala, Entoprocta,Platyhelminthes, Nemertea, Mollusca, Sipuncula, Annelida

Lophophorata: Ectoprocta, Brachiopoda, Phoronida

Ectoprocta

Brachiopoda

Phoronida

Lophophorata

Lophotrochozoa

RotiferaAcanthocephala

Platyhelminthes

Annelida

SipunculaEntoprocta

Nemertea

Mollusca

Parenchymia

Phylum SipunculaPhylum Sipuncula The Phylum Sipuncula (from Latin: The Phylum Sipuncula (from Latin:

meaning “little pipe”) consists of meaning “little pipe”) consists of approximately 250 species of benthic, approximately 250 species of benthic, marine wormlike animals, most from 15-30 marine wormlike animals, most from 15-30 cm in length (range 2mm to 70cm). cm in length (range 2mm to 70cm).

Sipunculids produce a trochophore larva Sipunculids produce a trochophore larva similar in structure to that of the annelids.similar in structure to that of the annelids.

Phylum SipunculaPhylum Sipuncula Sometimes referred to as the Sometimes referred to as the

“peanut worms” (probably for the “peanut worms” (probably for the gridlike pattern on their epidermis) gridlike pattern on their epidermis) most sipunculids burrow in sand or most sipunculids burrow in sand or silt or occupy crevices or empty silt or occupy crevices or empty mollusc shells or worm tubesmollusc shells or worm tubes

http://www.glaucus.org.uk/Sipunculus-nudus-RL.jpg

Sipunculid clipSipunculid clip One minute clip of sipunculidOne minute clip of sipunculid http://www.youtube.com/watch?v=S

1zQCa5cfcQ

Phylum SipunculaPhylum Sipuncula The body is unsegmented and divided into an The body is unsegmented and divided into an

anterior introvert and a posterior trunk.anterior introvert and a posterior trunk.

The introvert is a retractile structure at the The introvert is a retractile structure at the anterior end of the animal and can be half the anterior end of the animal and can be half the body length.body length.

Sipunculids have a fluid filled coelom and a Sipunculids have a fluid filled coelom and a hydrostatic skeleton. The pressure of the fluid hydrostatic skeleton. The pressure of the fluid in the coelom is used to extend the introvert.in the coelom is used to extend the introvert.

http://www.eol.org/pages/8871

Phylum SipunculaPhylum Sipuncula Sipunculids are generally non-selective Sipunculids are generally non-selective

deposit feeders and they use the deposit feeders and they use the ciliated tentacles or lobes surrounding ciliated tentacles or lobes surrounding the tip of the introvert to collect food. the tip of the introvert to collect food.

They eat a variety of small easy to They eat a variety of small easy to acquire food items: algae, unicellular acquire food items: algae, unicellular organisms, larvae and detritusorganisms, larvae and detritus

Phylum SipunculaPhylum Sipuncula The introvert is also used to burrowing The introvert is also used to burrowing

into sediments. into sediments.

Coelomic pressure is used to extend the Coelomic pressure is used to extend the introvert into the sediment and anchor it introvert into the sediment and anchor it in place. Retractor muscles then contract in place. Retractor muscles then contract pulling the introvert forward and drawing pulling the introvert forward and drawing the rest of the animal forward.the rest of the animal forward.

Sipunculid clipSipunculid clip

Sipunculid burying itself one minuteSipunculid burying itself one minute http://www.youtube.com/watch?v=a

q6kEX9igeI

Ectoprocta

Brachiopoda

Phoronida

Lophophorata

Lophotrochozoa

RotiferaAcanthocephala

Platyhelminthes

Annelida

SipunculaEntoprocta

Nemertea

Mollusca

Parenchymia

Phylum EntoproctaPhylum Entoprocta AKA the kamptozoans or the “goblet AKA the kamptozoans or the “goblet

worms”, entoprocts are small (1cm), worms”, entoprocts are small (1cm), sessile marine animals most of which are sessile marine animals most of which are colonial.colonial.

The body, which is covered by a thin The body, which is covered by a thin external cuticle consists of a long mobile external cuticle consists of a long mobile contractile stalk topped by a calyx, which contractile stalk topped by a calyx, which contains the organs and a crown of contains the organs and a crown of tentacles.tentacles.

http://www.biocyclopedia.com/index/general_zoology/phylum_entoprocta.php

Phylum EntoproctaPhylum Entoprocta Entoproct means “anus inside” and this Entoproct means “anus inside” and this

refers to the fact that the mouth and the refers to the fact that the mouth and the anus are surrounded by the ring of anus are surrounded by the ring of tentacles.tentacles.

The tentacles are solid and non rectracile, The tentacles are solid and non rectracile, Instead they can be rolled up and covered Instead they can be rolled up and covered by the intertentacular membrane.by the intertentacular membrane.

Phylum EntoproctaPhylum Entoprocta Entoprocts occur in shallow water Entoprocts occur in shallow water

and feed on suspended particles that and feed on suspended particles that they trap using mucus covered cilia they trap using mucus covered cilia on their tentacles.on their tentacles.

The food is directed down the The food is directed down the tentacles to the mouth.tentacles to the mouth.

Phylum EntoproctaPhylum Entoprocta Reproduction occurs either asexually by Reproduction occurs either asexually by

budding or sexually (they are budding or sexually (they are hermaphroditic).hermaphroditic).

Fertilized eggs are incubated in a pouch Fertilized eggs are incubated in a pouch within the calyx and the embryos are fed within the calyx and the embryos are fed by parental cells. The embryo develops by parental cells. The embryo develops into a free-swimming trochophore larva into a free-swimming trochophore larva that settles and metamorphoses into the that settles and metamorphoses into the adult form. adult form.

Ectoprocta

Brachiopoda

Phoronida

Lophophorata

Lophotrochozoa

RotiferaAcanthocephala

Platyhelminthes

Annelida

SipunculaEntoprocta

Nemertea

Mollusca

Parenchymia

Phylum RotiferaPhylum Rotifera Rotifers are named for their characteristic Rotifers are named for their characteristic

ciliated crown or ciliated crown or corona,corona, which when it which when it beats looks like a rotating wheel.beats looks like a rotating wheel.

Rotifers are tiny animals (most are 100-Rotifers are tiny animals (most are 100-300300µµm long and the largest only 3mm long) m long and the largest only 3mm long) the majority of which live in freshwater and the majority of which live in freshwater and are benthic inhabitants (live on the bottom). are benthic inhabitants (live on the bottom).

About 2000 species have been described.About 2000 species have been described.

9.1

Figure 15.18

Phylum RotiferaPhylum Rotifera The beating of the cilia in the corona draws The beating of the cilia in the corona draws

in plankton-containing water for food.in plankton-containing water for food.

The mouth opens to a modified muscular The mouth opens to a modified muscular pharynx known as a pharynx known as a mastaxmastax, which is a , which is a structure unique to rotifers.structure unique to rotifers.

The mastax has a set of complex jaws, which The mastax has a set of complex jaws, which are used to grasp and chew food.are used to grasp and chew food.

Rotifer video 1 minuteRotifer video 1 minute http://www.youtube.com/watch?v=cY

NJOVDQexA

Phylum RotiferaPhylum Rotifera One group of rotifers, the Bdelloid One group of rotifers, the Bdelloid

rotifers, are very unusual in that there rotifers, are very unusual in that there are no males, hermaphrodites, or are no males, hermaphrodites, or evidence of meiosis.evidence of meiosis.

Molecular evidence suggests that there Molecular evidence suggests that there has been only asexual reproduction in has been only asexual reproduction in this group for several million years.this group for several million years.

http://www.arcodiv.org/seaice/rotifers/Antarctic_rotifer_Philodina_gregaria_400x300.jpg

Phylum RotiferaPhylum Rotifera Because of the problem of accumulation of Because of the problem of accumulation of

deleterious mutations in lineages of deleterious mutations in lineages of exclusively asexually reproducing animals (a exclusively asexually reproducing animals (a process known as Muller’s ratchet) it is process known as Muller’s ratchet) it is unclear how the bdelloids have been able to unclear how the bdelloids have been able to dispense with sexual reproduction entirely.dispense with sexual reproduction entirely.

Other rotifers reproduce using a combination Other rotifers reproduce using a combination of sexual and asexual reproduction.of sexual and asexual reproduction.

Ectoprocta

Brachiopoda

Phoronida

Lophophorata

Lophotrochozoa

RotiferaAcanthocephala

Platyhelminthes

Annelida

SipunculaEntoprocta

Nemertea

Mollusca

Parenchymia

Phylum AcanthocephalaPhylum Acanthocephala Acanthocephalans are commonly known as Acanthocephalans are commonly known as

spiny-headed worms because of the spiny spiny-headed worms because of the spiny eversible proboscis they use to attach to eversible proboscis they use to attach to the gut of their host.the gut of their host.

All 1100 species of Acanthocephalan are All 1100 species of Acanthocephalan are endoparasitic and most parasitize fish, birds endoparasitic and most parasitize fish, birds and mammals. Most small 1mm to 3-4cm a and mammals. Most small 1mm to 3-4cm a few up to 1m long.few up to 1m long.

http://rydberg.biology.colostate.edu/Dissections/acanthocephala/acanthfemmal.jpg

Phylum AcanthocephalaPhylum Acanthocephala Bilaterally symmetricalBilaterally symmetrical No gutNo gut Body unsegmentedBody unsegmented Prominent spiny proboscisProminent spiny proboscis Body cavity is a pseudocoelom (mesoderm Body cavity is a pseudocoelom (mesoderm

lines only outer edges of blastocoel, body lines only outer edges of blastocoel, body cavity not lined with peritoneum).cavity not lined with peritoneum).

No respiratory or circulatory systemNo respiratory or circulatory system Simple nervous system single anterior Simple nervous system single anterior

ganglion with connecting nerves to organs.ganglion with connecting nerves to organs.

9.3

Figure 15.20

http://upload.wikimedia.org/wikipedia/commons/9/99/Acanthocephala_Rhadinorhynchus.jpg

Acanthocephalan proboscis

Phylum AcanthocephalaPhylum Acanthocephala Body wall covered with numerous Body wall covered with numerous

minute depressions which increase minute depressions which increase the surface area of tegument and the surface area of tegument and facilitate (as in cestodes) absorption facilitate (as in cestodes) absorption of food from host’s gut. of food from host’s gut.

As in cestodes, Acanthocephalans As in cestodes, Acanthocephalans lack a gut.lack a gut.

Phylum AcanthocephalaPhylum Acanthocephala Acanthocephalans have a lifecycle in which Acanthocephalans have a lifecycle in which

a vertebrate is the definitive host (in a vertebrate is the definitive host (in alimentary canal) and an invertebrate the alimentary canal) and an invertebrate the intermediate host.intermediate host.

Acanthocephalans, as other parasites do, Acanthocephalans, as other parasites do, modify the behavior of the intermediate modify the behavior of the intermediate host to enhance the chances of its being host to enhance the chances of its being eaten.eaten.

Phylum AcanthocephalaPhylum Acanthocephala For example, acanthocephalans that parasitize For example, acanthocephalans that parasitize

Gammarus,Gammarus, a small freshwater crustacean, a small freshwater crustacean, cause the cause the GammarusGammarus to alter its behavior in to alter its behavior in the presence of ducks, a common predator. the presence of ducks, a common predator.

Instead of diving to the bottom when a duck Instead of diving to the bottom when a duck appears, the appears, the GammarusGammarus swims into the light swims into the light and grasps tightly onto a piece of vegetation, and grasps tightly onto a piece of vegetation, greatly increasing its chances of being eaten. greatly increasing its chances of being eaten.

Phylum AcanthocephalaPhylum Acanthocephala The change in behavior appears to be caused by The change in behavior appears to be caused by

the Acanthocephalan pumping a serotonin-the Acanthocephalan pumping a serotonin-boosting molecule into the boosting molecule into the GammarusGammarus’ brain.’ brain.

This causes the This causes the GammarusGammarus to think it’s having to think it’s having sex and cling as it would if mating. Interestingly, sex and cling as it would if mating. Interestingly, the parasite’s manipulation also causes female the parasite’s manipulation also causes female GammarusGammarus to mimic the males mating behavior. to mimic the males mating behavior.

Phylum AcanthocephalaPhylum Acanthocephala Another Acanthocephalan that parasitizes pill Another Acanthocephalan that parasitizes pill

bugs causes them to reverse their normal bugs causes them to reverse their normal behavior and avoid humid, dark areas. behavior and avoid humid, dark areas.

Instead they wander in the open where they are Instead they wander in the open where they are much more vulnerable to birds, the much more vulnerable to birds, the acanthocephalans definitive host. acanthocephalans definitive host.

The parasite’s manipulations are very effective. The parasite’s manipulations are very effective. Although fewer than 1% of pill bugs are typically Although fewer than 1% of pill bugs are typically infected with acanthocephalan parasites, 30% of infected with acanthocephalan parasites, 30% of pill bugs delivered to nestlings are infected. pill bugs delivered to nestlings are infected.

Ectoprocta

Brachiopoda

Phoronida

Lophophorata

Lophotrochozoa

RotiferaAcanthocephala

Platyhelminthes

Annelida

SipunculaEntoprocta

Nemertea

Mollusca

Parenchymia

Phylum EctoproctaPhylum Ectoprocta Also known as the bryozoans or moss Also known as the bryozoans or moss

animals they are small (<0.5mm) colonial animals they are small (<0.5mm) colonial animals, but colonies can be up to 1 meter animals, but colonies can be up to 1 meter across (although most are 10cm or so)across (although most are 10cm or so)

Most are marine and form masses on Most are marine and form masses on rocks and other substrates where they rocks and other substrates where they feed on phytoplankton and other small feed on phytoplankton and other small organisms which they catch using cilia on organisms which they catch using cilia on their lophophore.their lophophore.

Lophopodella carteri

http://www.bio.umass.edu/biology/conn.river/bryozoa.html

lophophore

Phylum EctoproctaPhylum Ectoprocta Individual zooids are genetically identical. Individual zooids are genetically identical. The zooids are connected to each other The zooids are connected to each other

and surrounded by a protective calyx as in and surrounded by a protective calyx as in entoprocts.entoprocts.

Most zooids are feeding zooids called Most zooids are feeding zooids called autozooids. These use the lophophore to autozooids. These use the lophophore to feed. The tentacles are extended by feed. The tentacles are extended by hydrostatic pressure and prey is trapped hydrostatic pressure and prey is trapped using cilia using cilia

Phylum EctoproctaPhylum Ectoprocta The lophophore and mouth are mounted The lophophore and mouth are mounted

on a tube called an invert that can be on a tube called an invert that can be everted through an opening in the calyx everted through an opening in the calyx and rapidly withdrawn if threatened.and rapidly withdrawn if threatened.

The mouth is found within the ring of The mouth is found within the ring of tentacles but the anus is outside the tentacles but the anus is outside the ring (in contrast to entoprocts).ring (in contrast to entoprocts).

Phylum EctoproctaPhylum Ectoprocta Other types of zooids include Other types of zooids include

spinozooids which possess protective spinozooids which possess protective spines, gonozooids, which act as spines, gonozooids, which act as brood chambers for developing eggs brood chambers for developing eggs and modified autozooids called and modified autozooids called avicularia which use a modified avicularia which use a modified operculum to snap at threatening operculum to snap at threatening organisms. organisms.

www.marlin.ac.uk

Phylum EctoproctaPhylum Ectoprocta Colonies of ectoprocts in freshwater Colonies of ectoprocts in freshwater

temperate habitats die in the fall, but temperate habitats die in the fall, but leave behind statoblasts, which are leave behind statoblasts, which are groups of cells surrounded by a groups of cells surrounded by a protective envelope.protective envelope.

Zooids emerge in the spring and a Zooids emerge in the spring and a new colony forms by budding.new colony forms by budding.

Phylum EctoproctaPhylum Ectoprocta Ectoprocts have a rich fossil record Ectoprocts have a rich fossil record

and over 15,000 fossil species have and over 15,000 fossil species have been described. been described.

Fossils are known from as far back as Fossils are known from as far back as the Cambrian period (500mya).the Cambrian period (500mya).

Phylum EctoproctaPhylum Ectoprocta Ectoproct video 1 minuteEctoproct video 1 minute

http://www.youtube.com/watch?http://www.youtube.com/watch?v=tpifpqrQKRAv=tpifpqrQKRA

Ectoprocta

Brachiopoda

Phoronida

Lophophorata

Lophotrochozoa

RotiferaAcanthocephala

Platyhelminthes

Annelida

SipunculaEntoprocta

Nemertea

Mollusca

Parenchymia

Phylum BrachiopodaPhylum Brachiopoda Greek: Greek: brachion:brachion: branch; branch; pouspous: foot.: foot. The living brachiopods are the The living brachiopods are the

remnants of a once much more diverse remnants of a once much more diverse group. There are about 335 living group. There are about 335 living species vs > 26,000 fossil species.species vs > 26,000 fossil species.

Superficially similar in lifestyle and Superficially similar in lifestyle and external appearance to bivalve external appearance to bivalve molluscs.molluscs.

http://paleo.cortland.edu/tutorial/Brachiopods/Brachiopod%20Images/lingula.GIF

Brachiopod characteristicsBrachiopod characteristics The body is enclosed within a The body is enclosed within a

symmetrical bivalve shell as is the symmetrical bivalve shell as is the case in molluscs. However, unlike case in molluscs. However, unlike molluscs brahiopods have a molluscs brahiopods have a dorsoventrally oriented shell with two dorsoventrally oriented shell with two unequally sized valves unlike unequally sized valves unlike molluscs which have left and right molluscs which have left and right valves.valves.

Phylum BrachiopodaPhylum Brachiopoda Brachipods possess a stalk or pedicle Brachipods possess a stalk or pedicle

(1-30cm in length), which is typically (1-30cm in length), which is typically attached to rock or anchored in attached to rock or anchored in sedimentsediment

A large, anterior mantle cavity A large, anterior mantle cavity contains the lophophore which is contains the lophophore which is used for suspension feeding.used for suspension feeding.

Brachipod cross section: http://aalliiffaazzeellii.googlepages.com/pra1.gif  Principal organs of a brachiopod as typified by Terebratulina. (After R. C. Moore, ed., Treatise on Invertebrate Paleontology, pt. H, Geological Society of America, Inc., and University of Kansas Press, 1965)

Phylum BrachiopodaPhylum Brachiopoda The lophophore occupies much of the The lophophore occupies much of the

internal space of the brachipod and internal space of the brachipod and has a branched rather than circular has a branched rather than circular structure (hence the name as brach structure (hence the name as brach means a branch) with complex means a branch) with complex folding of the lophophore being folding of the lophophore being common.common.

http://rydberg.biology.colostate.edu/Dissections/terint.htm

Phylum BrachiopodaPhylum Brachiopoda Brachipods are entirely marine and Brachipods are entirely marine and

most occur in areas without strong most occur in areas without strong waves or currents.waves or currents.

They occur at depths ranging from They occur at depths ranging from the intertidal to the deep sea.the intertidal to the deep sea.

Ectoprocta

Brachiopoda

Phoronida

Lophophorata

Lophotrochozoa

RotiferaAcanthocephala

Platyhelminthes

Annelida

SipunculaEntoprocta

Nemertea

Mollusca

Parenchymia

Phylum PhoronidaPhylum Phoronida Sometimes called horseshoe worms Sometimes called horseshoe worms

they build tubes of chitin and filter they build tubes of chitin and filter feed using a lophophore. feed using a lophophore.

The are marine and occur in The are marine and occur in sediments between the intertidal and sediments between the intertidal and about 400m depth.about 400m depth.

Phylum PhoronidaPhylum Phoronida Most phoronids range in length from Most phoronids range in length from

2-20cm, but can reach 50 cm.2-20cm, but can reach 50 cm.

They secrete a tube of chitin and the They secrete a tube of chitin and the lower end of the animal is swollen into lower end of the animal is swollen into an ampulla, which anchors the animal an ampulla, which anchors the animal and allows it to quickly retract its and allows it to quickly retract its lophophore into the tube. lophophore into the tube.

Phylum PhoronidaPhylum Phoronida Phoronids can be extremely Phoronids can be extremely

abundant numbering thousands of abundant numbering thousands of individuals per sq. meter. They are individuals per sq. meter. They are unpalatable to many predators and unpalatable to many predators and that likely explains the high that likely explains the high densities.densities.

Phylum PhoronidaPhylum Phoronida Phoronids feed on a variety of small Phoronids feed on a variety of small

filterable prey including algae, small filterable prey including algae, small invertebrates and flagellates which invertebrates and flagellates which are caught using the lophophore.are caught using the lophophore.

Phylum PhoronidaPhylum Phoronida Some species are hermaphroditic Some species are hermaphroditic

and the rest dioecious. Eggs are in and the rest dioecious. Eggs are in many species brooded for a while many species brooded for a while before being released into the water.before being released into the water.

Most species develop free-swimming Most species develop free-swimming larvae that feed on plankton that larvae that feed on plankton that they catch using tentacles.they catch using tentacles.

http://en.wikipedia.org/wiki/File:Phoronid_ASlotwinski.jpgPhoronid larva (they are called actinotrochs

Phylum PhoronidaPhylum Phoronida After a larval period of about 20 days After a larval period of about 20 days

the larva settles on the bottom and in the larva settles on the bottom and in about 30 minutes undergoes a rapid about 30 minutes undergoes a rapid metamorphosis in which the larval metamorphosis in which the larval hood and tentacles are reabsorbed, hood and tentacles are reabsorbed, the adult lophophore is formed and the adult lophophore is formed and the gut forms a u-bend with the anus the gut forms a u-bend with the anus opening outside the tentacles.opening outside the tentacles.

Phylum PhoronidaPhylum Phoronida There are only a dozen described There are only a dozen described

species, but this is certainly an species, but this is certainly an underestimate as more than 25 underestimate as more than 25 larval forms have been described.larval forms have been described.

Phylum PhoronidaPhylum Phoronida Phoronid worm (1 minute)Phoronid worm (1 minute)

http://www.youtube.com/watch?v=j-http://www.youtube.com/watch?v=j-Z1bibYY1wZ1bibYY1w