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Lophotrochozoa “Minor Phyla”. Ecdysozoa : Onychophora, Tardigrada, Arthropoda, Nematoda, Nematomorpha, Kinorhyncha, Loricifera, Priapulida Gastrotricha.

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Presentation on theme: "Lophotrochozoa “Minor Phyla”. Ecdysozoa : Onychophora, Tardigrada, Arthropoda, Nematoda, Nematomorpha, Kinorhyncha, Loricifera, Priapulida Gastrotricha."— Presentation transcript:

1 Lophotrochozoa “Minor Phyla”

2 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

3 Ectoprocta Brachiopoda Phoronida Lophophorata Lophotrochozoa Rotifera Acanthocephala Platyhelminthes Annelida Sipuncula Entoprocta Nemertea Mollusca Parenchymia

4 Phylum Sipuncula The Phylum Sipuncula (from Latin: meaning “little pipe”) consists of approximately 250 species of benthic, marine wormlike animals, most from cm in length (range 2mm to 70cm). The Phylum Sipuncula (from Latin: meaning “little pipe”) consists of approximately 250 species of benthic, marine wormlike animals, most from cm in length (range 2mm to 70cm). Sipunculids produce a trochophore larva similar in structure to that of the annelids. Sipunculids produce a trochophore larva similar in structure to that of the annelids.

5 Phylum Sipuncula Sometimes referred to as the “peanut worms” (probably for the gridlike pattern on their epidermis) most sipunculids burrow in sand or silt or occupy crevices or empty mollusc shells or worm tubes Sometimes referred to as the “peanut worms” (probably for the gridlike pattern on their epidermis) most sipunculids burrow in sand or silt or occupy crevices or empty mollusc shells or worm tubes

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7 Sipunculid clip One minute clip of sipunculid One minute clip of sipunculid a5cfcQ a5cfcQ a5cfcQ a5cfcQ

8 Phylum Sipuncula The body is unsegmented and divided into an anterior introvert and a posterior trunk. The body is unsegmented and divided into an anterior introvert and a posterior trunk. The introvert is a retractile structure at the anterior end of the animal and can be half the body length. The introvert is a retractile structure at the anterior end of the animal and can be half the body length. Sipunculids have a fluid filled coelom and a hydrostatic skeleton. The pressure of the fluid in the coelom is used to extend the introvert. Sipunculids have a fluid filled coelom and a hydrostatic skeleton. The pressure of the fluid in the coelom is used to extend the introvert.

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10 Phylum Sipuncula Sipunculids are generally non-selective deposit feeders and they use the ciliated tentacles or lobes surrounding the tip of the introvert to collect food. Sipunculids are generally non-selective deposit feeders and they use the ciliated tentacles or lobes surrounding the tip of the introvert to collect food. They eat a variety of small easy to acquire food items: algae, unicellular organisms, larvae and detritus They eat a variety of small easy to acquire food items: algae, unicellular organisms, larvae and detritus

11 Phylum Sipuncula The introvert is also used to burrowing into sediments. The introvert is also used to burrowing into sediments. Coelomic pressure is used to extend the introvert into the sediment and anchor it in place. Retractor muscles then contract pulling the introvert forward and drawing the rest of the animal forward. Coelomic pressure is used to extend the introvert into the sediment and anchor it in place. Retractor muscles then contract pulling the introvert forward and drawing the rest of the animal forward.

12 Sipunculid clip Sipunculid burying itself one minute Sipunculid burying itself one minute X9igeI X9igeI X9igeI X9igeI

13 Ectoprocta Brachiopoda Phoronida Lophophorata Lophotrochozoa Rotifera Acanthocephala Platyhelminthes Annelida Sipuncula Entoprocta Nemertea Mollusca Parenchymia

14 Phylum Entoprocta AKA the kamptozoans or the “goblet worms”, entoprocts are small (1cm), sessile marine animals most of which are colonial. AKA the kamptozoans or the “goblet worms”, entoprocts are small (1cm), sessile marine animals most of which are colonial. The body, which is covered by a thin external cuticle consists of a long mobile contractile stalk topped by a calyx, which contains the organs and a crown of tentacles. The body, which is covered by a thin external cuticle consists of a long mobile contractile stalk topped by a calyx, which contains the organs and a crown of tentacles.

15 al_zoology/phylum_entoprocta.php

16 Phylum Entoprocta Entoproct means “anus inside” and this refers to the fact that the mouth and the anus are surrounded by the ring of tentacles. Entoproct means “anus inside” and this refers to the fact that the mouth and the anus are surrounded by the ring of tentacles. The tentacles are solid and non rectracile, Instead they can be rolled up and covered by the intertentacular membrane. The tentacles are solid and non rectracile, Instead they can be rolled up and covered by the intertentacular membrane.

17 Phylum Entoprocta Entoprocts occur in shallow water and feed on suspended particles that they trap using mucus covered cilia on their tentacles. Entoprocts occur in shallow water and feed on suspended particles that they trap using mucus covered cilia on their tentacles. The food is directed down the tentacles to the mouth. The food is directed down the tentacles to the mouth.

18 Phylum Entoprocta Reproduction occurs either asexually by budding or sexually (they are hermaphroditic). Reproduction occurs either asexually by budding or sexually (they are hermaphroditic). Fertilized eggs are incubated in a pouch within the calyx and the embryos are fed by parental cells. The embryo develops into a free-swimming trochophore larva that settles and metamorphoses into the adult form. Fertilized eggs are incubated in a pouch within the calyx and the embryos are fed by parental cells. The embryo develops into a free-swimming trochophore larva that settles and metamorphoses into the adult form.

19 Ectoprocta Brachiopoda Phoronida Lophophorata Lophotrochozoa Rotifera Acanthocephala Platyhelminthes Annelida Sipuncula Entoprocta Nemertea Mollusca Parenchymia

20 Phylum Rotifera Rotifers are named for their characteristic ciliated crown or corona, which when it beats looks like a rotating wheel. Rotifers are named for their characteristic ciliated crown or corona, which when it beats looks like a rotating wheel. Rotifers are tiny animals (most are µm long and the largest only 3mm long) the majority of which live in freshwater and are benthic inhabitants (live on the bottom). Rotifers are tiny animals (most are µm long and the largest only 3mm long) the majority of which live in freshwater and are benthic inhabitants (live on the bottom). About 2000 species have been described. About 2000 species have been described.

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22 Phylum Rotifera The beating of the cilia in the corona draws in plankton-containing water for food. The beating of the cilia in the corona draws in plankton-containing water for food. The mouth opens to a modified muscular pharynx known as a mastax, which is a structure unique to rotifers. The mouth opens to a modified muscular pharynx known as a mastax, which is a structure unique to rotifers. The mastax has a set of complex jaws, which are used to grasp and chew food. The mastax has a set of complex jaws, which are used to grasp and chew food.

23 Rotifer video 1 minute Rotifer video 1 minute VDQexA VDQexA VDQexA VDQexA

24 Phylum Rotifera One group of rotifers, the Bdelloid rotifers, are very unusual in that there are no males, hermaphrodites, or evidence of meiosis. One group of rotifers, the Bdelloid rotifers, are very unusual in that there are no males, hermaphrodites, or evidence of meiosis. Molecular evidence suggests that there has been only asexual reproduction in this group for several million years. Molecular evidence suggests that there has been only asexual reproduction in this group for several million years.

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26 Phylum Rotifera Because of the problem of accumulation of deleterious mutations in lineages of exclusively asexually reproducing animals (a process known as Muller’s ratchet) it is unclear how the bdelloids have been able to dispense with sexual reproduction entirely. Because of the problem of accumulation of deleterious mutations in lineages of exclusively asexually reproducing animals (a process known as Muller’s ratchet) it is unclear how the bdelloids have been able to dispense with sexual reproduction entirely. Other rotifers reproduce using a combination of sexual and asexual reproduction. Other rotifers reproduce using a combination of sexual and asexual reproduction.

27 Ectoprocta Brachiopoda Phoronida Lophophorata Lophotrochozoa Rotifera Acanthocephala Platyhelminthes Annelida Sipuncula Entoprocta Nemertea Mollusca Parenchymia

28 Phylum Acanthocephala Acanthocephalans are commonly known as spiny-headed worms because of the spiny eversible proboscis they use to attach to the gut of their host. Acanthocephalans are commonly known as spiny-headed worms because of the spiny eversible proboscis they use to attach to the gut of their host. All 1100 species of Acanthocephalan are endoparasitic and most parasitize fish, birds and mammals. Most small 1mm to 3- 4cm a few up to 1m long. All 1100 species of Acanthocephalan are endoparasitic and most parasitize fish, birds and mammals. Most small 1mm to 3- 4cm a few up to 1m long.

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30 Phylum Acanthocephala Bilaterally symmetrical Bilaterally symmetrical No gut No gut Body unsegmented Body unsegmented Prominent spiny proboscis Prominent spiny proboscis Body cavity is a pseudocoelom (mesoderm lines only outer edges of blastocoel, body cavity not lined with peritoneum). Body cavity is a pseudocoelom (mesoderm lines only outer edges of blastocoel, body cavity not lined with peritoneum). No respiratory or circulatory system No respiratory or circulatory system Simple nervous system single anterior ganglion with connecting nerves to organs. Simple nervous system single anterior ganglion with connecting nerves to organs.

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32 s.jpg Acanthocephalan proboscis

33 Phylum Acanthocephala Body wall covered with numerous minute depressions which increase the surface area of tegument and facilitate (as in cestodes) absorption of food from host’s gut. Body wall covered with numerous minute depressions which increase the surface area of tegument and facilitate (as in cestodes) absorption of food from host’s gut. As in cestodes, Acanthocephalans lack a gut. As in cestodes, Acanthocephalans lack a gut.

34 Phylum Acanthocephala Acanthocephalans have a lifecycle in which a vertebrate is the definitive host (in alimentary canal) and an invertebrate the intermediate host. Acanthocephalans have a lifecycle in which a vertebrate is the definitive host (in alimentary canal) and an invertebrate the intermediate host. Acanthocephalans, as other parasites do, modify the behavior of the intermediate host to enhance the chances of its being eaten. Acanthocephalans, as other parasites do, modify the behavior of the intermediate host to enhance the chances of its being eaten.

35 Phylum Acanthocephala For example, acanthocephalans that parasitize Gammarus, a small freshwater crustacean, cause the Gammarus to alter its behavior in the presence of ducks, a common predator. For example, acanthocephalans that parasitize Gammarus, a small freshwater crustacean, cause the Gammarus to alter its behavior in the presence of ducks, a common predator. Instead of diving to the bottom when a duck appears, the Gammarus swims into the light and grasps tightly onto a piece of vegetation, greatly increasing its chances of being eaten. Instead of diving to the bottom when a duck appears, the Gammarus swims into the light and grasps tightly onto a piece of vegetation, greatly increasing its chances of being eaten.

36 Phylum Acanthocephala The change in behavior appears to be caused by the Acanthocephalan pumping a serotonin- boosting molecule into the Gammarus’ brain. The change in behavior appears to be caused by the Acanthocephalan pumping a serotonin- boosting molecule into the Gammarus’ brain. This causes the Gammarus to think it’s having sex and cling as it would if mating. Interestingly, the parasite’s manipulation also causes female Gammarus to mimic the males mating behavior. This causes the Gammarus to think it’s having sex and cling as it would if mating. Interestingly, the parasite’s manipulation also causes female Gammarus to mimic the males mating behavior.

37 Phylum Acanthocephala Another Acanthocephalan that parasitizes pill bugs causes them to reverse their normal behavior and avoid humid, dark areas. Another Acanthocephalan that parasitizes pill bugs causes them to reverse their normal behavior and avoid humid, dark areas. Instead they wander in the open where they are much more vulnerable to birds, the acanthocephalans definitive host. Instead they wander in the open where they are much more vulnerable to birds, the acanthocephalans definitive host. The parasite’s manipulations are very effective. Although fewer than 1% of pill bugs are typically infected with acanthocephalan parasites, 30% of pill bugs delivered to nestlings are infected. The parasite’s manipulations are very effective. Although fewer than 1% of pill bugs are typically infected with acanthocephalan parasites, 30% of pill bugs delivered to nestlings are infected.

38 Ectoprocta Brachiopoda Phoronida Lophophorata Lophotrochozoa Rotifera Acanthocephala Platyhelminthes Annelida Sipuncula Entoprocta Nemertea Mollusca Parenchymia

39 Phylum Ectoprocta Also known as the bryozoans or moss animals they are small (<0.5mm) colonial animals, but colonies can be up to 1 meter across (although most are 10cm or so) Also known as the bryozoans or moss animals they are small (<0.5mm) colonial animals, but colonies can be up to 1 meter across (although most are 10cm or so) Most are marine and form masses on rocks and other substrates where they feed on phytoplankton and other small organisms which they catch using cilia on their lophophore. Most are marine and form masses on rocks and other substrates where they feed on phytoplankton and other small organisms which they catch using cilia on their lophophore.

40 Lophopodella carteri lophophore

41 Phylum Ectoprocta Individual zooids are genetically identical. Individual zooids are genetically identical. The zooids are connected to each other and surrounded by a protective calyx as in entoprocts. The zooids are connected to each other and surrounded by a protective calyx as in entoprocts. Most zooids are feeding zooids called autozooids. These use the lophophore to feed. The tentacles are extended by hydrostatic pressure and prey is trapped using cilia Most zooids are feeding zooids called autozooids. These use the lophophore to feed. The tentacles are extended by hydrostatic pressure and prey is trapped using cilia

42 Phylum Ectoprocta The lophophore and mouth are mounted on a tube called an invert that can be everted through an opening in the calyx and rapidly withdrawn if threatened. The lophophore and mouth are mounted on a tube called an invert that can be everted through an opening in the calyx and rapidly withdrawn if threatened. The mouth is found within the ring of tentacles but the anus is outside the ring (in contrast to entoprocts). The mouth is found within the ring of tentacles but the anus is outside the ring (in contrast to entoprocts).

43 Phylum Ectoprocta Other types of zooids include spinozooids which possess protective spines, gonozooids, which act as brood chambers for developing eggs and modified autozooids called avicularia which use a modified operculum to snap at threatening organisms. Other types of zooids include spinozooids which possess protective spines, gonozooids, which act as brood chambers for developing eggs and modified autozooids called avicularia which use a modified operculum to snap at threatening organisms.

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45 Phylum Ectoprocta Colonies of ectoprocts in freshwater temperate habitats die in the fall, but leave behind statoblasts, which are groups of cells surrounded by a protective envelope. Colonies of ectoprocts in freshwater temperate habitats die in the fall, but leave behind statoblasts, which are groups of cells surrounded by a protective envelope. Zooids emerge in the spring and a new colony forms by budding. Zooids emerge in the spring and a new colony forms by budding.

46 Phylum Ectoprocta Ectoprocts have a rich fossil record and over 15,000 fossil species have been described. Ectoprocts have a rich fossil record and over 15,000 fossil species have been described. Fossils are known from as far back as the Cambrian period (500mya). Fossils are known from as far back as the Cambrian period (500mya).

47 Phylum Ectoprocta Ectoproct video 1 minute Ectoproct video 1 minute QKRA QKRA

48 Ectoprocta Brachiopoda Phoronida Lophophorata Lophotrochozoa Rotifera Acanthocephala Platyhelminthes Annelida Sipuncula Entoprocta Nemertea Mollusca Parenchymia

49 Phylum Brachiopoda Greek: brachion: branch; pous: foot. Greek: brachion: branch; pous: foot. The living brachiopods are the remnants of a once much more diverse group. There are about 335 living species vs > 26,000 fossil species. The living brachiopods are the remnants of a once much more diverse group. There are about 335 living species vs > 26,000 fossil species. Superficially similar in lifestyle and external appearance to bivalve molluscs. Superficially similar in lifestyle and external appearance to bivalve molluscs.

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51 Brachiopod characteristics The body is enclosed within a symmetrical bivalve shell as is the case in molluscs. However, unlike molluscs brahiopods have a dorsoventrally oriented shell with two unequally sized valves unlike molluscs which have left and right valves. The body is enclosed within a symmetrical bivalve shell as is the case in molluscs. However, unlike molluscs brahiopods have a dorsoventrally oriented shell with two unequally sized valves unlike molluscs which have left and right valves.

52 Phylum Brachiopoda Brachipods possess a stalk or pedicle (1- 30cm in length), which is typically attached to rock or anchored in sediment Brachipods possess a stalk or pedicle (1- 30cm in length), which is typically attached to rock or anchored in sediment A large, anterior mantle cavity contains the lophophore which is used for suspension feeding. A large, anterior mantle cavity contains the lophophore which is used for suspension feeding.

53 Brachipod cross section: 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)

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

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56 Phylum Brachiopoda Brachipods are entirely marine and most occur in areas without strong waves or currents. Brachipods are entirely marine and most occur in areas without strong waves or currents. They occur at depths ranging from the intertidal to the deep sea. They occur at depths ranging from the intertidal to the deep sea.

57 Ectoprocta Brachiopoda Phoronida Lophophorata Lophotrochozoa Rotifera Acanthocephala Platyhelminthes Annelida Sipuncula Entoprocta Nemertea Mollusca Parenchymia

58 Phylum Phoronida Sometimes called horseshoe worms they build tubes of chitin and filter feed using a lophophore. Sometimes called horseshoe worms they build tubes of chitin and filter feed using a lophophore. The are marine and occur in sediments between the intertidal and about 400m depth. The are marine and occur in sediments between the intertidal and about 400m depth.

59 Phylum Phoronida Most phoronids range in length from 2- 20cm, but can reach 50 cm. Most phoronids range in length from 2- 20cm, but can reach 50 cm. They secrete a tube of chitin and the lower end of the animal is swollen into an ampulla, which anchors the animal and allows it to quickly retract its lophophore into the tube. They secrete a tube of chitin and the lower end of the animal is swollen into an ampulla, which anchors the animal and allows it to quickly retract its lophophore into the tube.

60 Phylum Phoronida Phoronids can be extremely abundant numbering thousands of individuals per sq. meter. They are unpalatable to many predators and that likely explains the high densities. Phoronids can be extremely abundant numbering thousands of individuals per sq. meter. They are unpalatable to many predators and that likely explains the high densities.

61 Phylum Phoronida Phoronids feed on a variety of small filterable prey including algae, small invertebrates and flagellates which are caught using the lophophore. Phoronids feed on a variety of small filterable prey including algae, small invertebrates and flagellates which are caught using the lophophore.

62 Phylum Phoronida Some species are hermaphroditic and the rest dioecious. Eggs are in many species brooded for a while before being released into the water. Some species are hermaphroditic and the rest dioecious. Eggs are in many species brooded for a while before being released into the water. Most species develop free-swimming larvae that feed on plankton that they catch using tentacles. Most species develop free-swimming larvae that feed on plankton that they catch using tentacles.

63 Phoronid larva (they are called actinotrochs

64 Phylum Phoronida After a larval period of about 20 days the larva settles on the bottom and in about 30 minutes undergoes a rapid metamorphosis in which the larval hood and tentacles are reabsorbed, the adult lophophore is formed and the gut forms a u-bend with the anus opening outside the tentacles. After a larval period of about 20 days the larva settles on the bottom and in about 30 minutes undergoes a rapid metamorphosis in which the larval hood and tentacles are reabsorbed, the adult lophophore is formed and the gut forms a u-bend with the anus opening outside the tentacles.

65 Phylum Phoronida There are only a dozen described species, but this is certainly an underestimate as more than 25 larval forms have been described. There are only a dozen described species, but this is certainly an underestimate as more than 25 larval forms have been described.

66 Phylum Phoronida Phoronid worm (1 minute) Phoronid worm (1 minute) Z1bibYY1w Z1bibYY1w


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