Nine minor phyla to

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Three major protostomous eucoelomate phyla
Nine minor phyla to consider
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Problematic Phyla

• Mixture of characters
• Where to put them
• Did segmentation evolve once or many times?
• What to do with organisms with both protostome
  and deutrostome characteristics?
• What to do if molecular techniques contradict
  morphological evidence?

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Two groupings

• Lophotrochozoans
• Sipuncula - peanut worms
• Echiura spoon worms
• Lophophore worms
• Phoronida lophophorate worms
• Ectoprocta bryozoans or moss animals
• Brachiopoda lamp shells
• And annelids and mollusks in some classifications

Marine benthic worms
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Two groupings

• Ecdysozoans
• Pentastomida tongue worms
• Onychophora velvet worms
• Tardigradia water bears
• Chaetoghatha arrow worms
• And arthropods others in some classifications

Unclear position
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Phylum Sipuncula

• Peanut worms
• Disturbed contract into peanut shape
• 250 benthic species
• Tentacled proboscis
• Collect organic matter on mucus
• Not metameric
• No setae
• Trochophore larvae

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Phylum Echiura

• Marine worms
• Spoon worms
• 160 species
• Organic material collected in gutter
• Moved to mouth
• Closed circulation
• Setae
• No metamerism

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-- the ciliated probocis can be quite large
Phylum Echiura
-- detritus feeders
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Internal anatomy

• Multiple pair nephridium
• Suggest segmentation
• Relation to annelids

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Lophophorates

• Lophophore
• Cilliated tentacles on a ridge
• Surround mouth
• Not anus
• U-shaped digestive tract
• Anus outside tentacles
• Coelom divided into 3 parts

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Phylum Phoronida

• 10 species
• Leathery or chitinous tube
• Coelom divided into 3 parts
• Protocoel
• Mesocoel
• Metacoel
• Similar to deutrostomes
• Closed circulation
• No heart

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Phylum Brachipoda

• Bivalve like shell
• Lamp shells
• Lophophore inside shell
• 12 000 fossil species
• 325 living species
• Open circulation
• Heart
• Deutrostome like development

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Phylum Ectoprocta

• Bryozoa
• 4000 species
• Very small
• Mostly less than 0.5mm
• Colonial
• biofoulants
• Can have stiffened body wall
• Respiratory, vascular and excretory organs absent

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Ecdysozoan group

• Molting animals
• Cuticle shell
• Includes arthropods and nematodes
• Separate sexes

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Phylum Pentastomida

• Tongue worms
• 5 mouth parts
• 130 worms
• Parasites vertebrate respiratory system
• Segmented appearance
• Some argue related to Branchiura
• Lack organs for respiration, circulation,
  excretion

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Phylum Onychophora

• Velvet worms
• 70 species
• Paired appendages
• Biramous
• Have annelid and arthropod characteristics

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OnychophoraInsect/arthropod characters

• Trachea with spiracles
• Cuticle not true exoskeleton
• Single pair antennae
• Open circulation

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OnychophoraAnnelid characters

• Segmentally arranged nephridia
• Muscular pody wall
• Annelid like eye

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Phylum Tardigradia

• Water bears
• 300-400 species
• Arthropod like characters
• Muscles attach to exoskeleton
• Malphagian tubules
• video

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Arthropoda Pentastomida
Onychophora
Annelida
Tardigrada
2) nephridia replaced by Malpighian glands
1) muscles attach to exoskeleton
3) growth by ecdysis
2) haemocoel and open circulation
1) a tracheal system with numerous spiracles
From Fig. 13.13
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Phylum Chaetognatha

• Deutrostome-like development
• Molecular evidence suggests relation to nematodes

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Phylum Chaetegnatha

• Arrow worms
• Pelagic marine worm
• Name spines around mouth
• Spines snap down on prey
• Important predator copepods and fish
• 65 species
• Up to 10 cm

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Protostomes give rise to Deuterostomes
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Chordata
Cephalochordata
Vertebrata
Urochordata
Hemichordata
Echinodermata
Vertebrae
Chordate characteristics throughout life
Notochord
Tadpole like larvae with post-anal tail
Dorsal Hollow Nerve Chord
Gill Slits in pharynx
Deuterostomes
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Deutrostomes

• Phylum Echinodermata
• Phylum Hemichordata
• Phylum Chordata
• Subphylum Urochordata
• Subphylum Cephalochordata
• Subphylum Vertebrata