Animal Diversity Unit 2

Ecdysozoa

• SYnapomorphy: 3 layered cuticle that molts (ecdysis)

• no locomotor cilia

• respiratory/circulatory sys

Phylum Loricifera - Ecdysozoa

• undescribed

• mircoscopic

• diagnostic: lorica - armor like protective case

• Live bet. sand + deve. brain

Phylum Priapulida - Ecdysozoa

• Penis worm

• Feed on annelids

• Hemocoel

• Mouth - eversible proboscis

Phylum Kinorhycha - Ecdysozoa

• Undesrcibed

• small

• Segmented body with spines exten out for locomotion

Phylum Nematomorpha - Ecdysozoa

• adult worms who larvae are manipulative parastic that infects arthopods who seek out water

• damp/freshwater

• no developed organ sys/ only longitudinal muscle

Phylum Nematoda - Ecdysozoa

• Diverse - famous parasities hookworm

• all over

• Long. but no circular muslces ; stiffended crossed fiber array which is antagonist to long, only bend

Panarthropoda (header) - Ecdysozoa

• Segmentation, paired appendages

• Ladder like nervous sys.

Tardigrada - Panarthropoda (header) - Ecdysozoa

• Water bears

• super small

• aquatic

• can survive in extreme conditions and go under cryptobiosis when unfavorable conditions

• Anatomy: premeable chitinous cuticle line gut, no respiratory system, hemocoel, lobopods (apendages with claws that can bend in any direction)

• Specialize muscle → walk

• Complex intestinal tract

Phylum Onycophora - Panarthropoda (header) - Ecdysozoa

• Velvet worms

• moist temp

• mixture of annelid/arthropod

• Thin chitinous cuticle molted

• Papillae for sensing environment

• propulsion generated by muscles in the limbs , power, rest position, head bears three pair of appendages ; anterior: antenannae, second mandibles, 3rd papillae

• Nervous sys: ladder, sensilla body covered with for senses

• Capture prey using slime glands

Arthropoda → Panarthropoda → Ecdysozoa

• Tons

• evolve to fly

• protostome bilaterians

• segmented body

• chitinous skeleton with ecydsis

• jointed and paired segemented appendages → serially homologous → homonomy or heteronomy → similar part = tagma. specialization of appendages. moncondylic joint: move one diection while dicondylic joint has two points (all arthropod legs) hinge

• Two gr: chelicerata + mandibulata

• Exoskeleton : epicuticle & procuticle (inner)

• Fly, walk (power+ rest), swim

Ecdysis

1. Intermolt: period bet. molts (most time spent)

2. Proecdysis: preparatory stage for molting

3. ecdysis: shedding of the old skeleton where animal is vulnerable.

4. Post-ecdysis: Takes days for hardening of new cuticle

Trilobitomorpha - arthropoda

• Extinct (from cambrian - to Permian Triassic extinction event)

• Exoskeleton, segmentation, paired appendages, compound eyes (calcium carbonate)

• Tagmata (segments): sephalon, thorax, pygidium

Chelicerata - arthropoda

• The other major clade is mandibulata

• diverse (spiders, scorpions, mites, horeshoe crabs, sea spiders)

• Chelicerate: body divided into two tagmata (prosoma + abdomen [respiratory])

• Hemocoel (open circulatory sys)

• The first pair of appendages on the second segment = chelicerae (jaws)

• pedipalps

• 4 pair of walking legs

Xiphosura - Chelicerata - arthropoda

• Horseshoe crabs (living fossil) → they retain many ancestral ecologies

• Lagerst member

• shallow coastal waters

• Lack segmentation, immobile tagma, long tail, pair of compound eyes

• gnathobases grind food when they walk

• abdomen (book gills)

• omnivores

Pycnogonida - Chelicerata - arthropoda

• Sea spiders

• Marine (common)

• Body is narrow, 7 segments, dorsal eye, oxygen diffuse in pores of its legs

Arachnida - Chelicerata - arthropoda

• Majority of chelicerates

• spiders, scorpions, mites, ticks

• terrestrial

• two tagmata, pedipalps, 4 pairs of walking legs, chelicerae, telson (venom bulb)

• abdomen may unsegmented

• mating rituals

Scorpiones- Arachnida - Chelicerata - arthropoda

• early are aquatic , had gills, lacked claws

• terrestrial, nocturnal, reclusive

• cephalothorax, long seg. abdomen, telson, large pedipalps , book lungs (4 pairs), extensive parental care

Order Amblypgi - Arachnida - Chelicerata - arthropoda

• WHip spiders

• Chelicerae are small fangs

• large raptorial pedipalps , book lungs

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Order Uropygi - Arachnida - Chelicerata - arthropoda

• Whip scorpions

• Abdomen ends in a long flagellum

Order Araneae - Arachnida - Chelicerata - arthropoda

• Most specious gr. of chelicerates

• terrestrial

• silk, two tagmata, connected by pedicel, 8 anterior eyes, 1 pair book lungs, sternum, spinnerets, 6 types of silk glands

• Hunting spiders (jumping spiders)

• liquify their prey

Order Pseudoscorpiones - Arachnida - Chelicerata - arthropoda

• small arachnids

• no book lungs - respiration via tracheal sys. , pedipalp claws (venmon), silk

Order Solifugae - Arachnida - Chelicerata - arthropoda

• Sun spiders

• no book lungs - tracheal sys

• First legs = antennae ; large chelicerae

Ticks & mites

• can transmit pathogens → chemoreceptors to indentify host

• Live most of its life off soil

• Acari form: lack of seg, tagmata, have cephalothorax that has gnathosoma (feed stru.), small , 4 legs

Order Opilones

• daddy longlegs

• humid environments , not produce silk/toxins, no bites

• can self amputate

Mandibulata - arthropoda

• millipedes…

• body consist of trachea, series of unspecialized segments, mandibles, antennae, 3 distinct tagmata

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Myriapods - Mandibulata - arthropoda

•Body is composed of a head with an elongate trunk with many segments

•Trunk is not divided into a thorax and abdomen

•Usually simple median eyes

•Mouth parts lie on the ventral side of the head

•Upper “lip” is covered by the labrum

•Lower “lip” is covered by the maxillae

•Mandible pair in the mouth

•First trunk segment appendages = maxillipeds

•Gas exchange occurs via tracheal system

•However, spiracles cannot be closed

•How do you think this limits these organisms?

•Myriapods are generally limited to living in humid environments because they are vulnerable to water loss

Chilopoda (Centipedes) - Mandibulata - arthropoda

* (odd) number of legs , one pair per segment

humid tropics, nocturnal

poison fang predators

•Centipedes are trignathic - 3 jaws

•They have mandible, maxillae and a second pair of maxillae

•Appendages of the trunk start with the venom tipped forcipules (thought to be homologous to maxillipeds)

Diplopoda (Millipedes) - Mandibulata - arthropoda

• 1000 legs

• nocturnal detritivores

•Built like tiny tanks

•Exoskeleton is heavily calcified

•Body is divided into a head and heavily segmented trunk

•First head appendage bears antennae composed of 8 articles

•two pairs of mouth parts instead of three

•Each segment of the millipede bears two pairs of legs and two spiracles (because each segment is actually a pair of fused segments)

•Millipedes coordinate locomotion on both sides of the body synchronizing the power strokes

*Toxins for predators to make them taste no good

Crustaceans - Pancrustacea - Arthropoda

• crabs, shrimps, lobsters…

• body is divided into head (5 appendages), thorax, abdomen fused

•Head bears five paired appendages

•1^st pair is antennae (or antennules)

•2^nd pair is also antennae thought to be homologous to the chelicerae in chelicerates

•3^rd pair of appendages are the mandibles

•4^th and 5^th pair of appendages are feeding maxillae

•Also, often conspicuous stalked compound eyes

•Small crustaceans often have no special gas-exchange structures

•In some species the thin permeable cuticle functions in gas exchange

•In larger crustaceans gills are present

•Typically located in a protected branchial chamber

Development ——————

•Direct - juvenile is born resembling an adult

•Indirect - juvenile passes through a larval stage before taking adult form

Larva = nauplius