Phylum Nematoda The round worms Theyre EVERYWHERE Anatomy

Phylum Nematoda The round worms They’re EVERYWHERE!!!!!

Anatomy of a Nematode No circulatory system Hydrostatic skeleton Longitudinal muscles

Ectoparasitic nematode feeding on a tomato root Stylet

Ascaris lumbricoides - round worm Common mammal parasite Female Male Larva in lung

Necator - hookworm

Trichinella spiralis - trichinosis Infection with ingestion of raw/poorly cooked pork Encysted larva in muscle

Enterobius vermicularis - pin worm Most common human parasitic infection Most common nematode infection

Dracunculus medinensis - filarial worm The Guinea Worm Copepod is intermediate host 1. Infected copepod ingested 2. Larvae enter gut wall, mature in deep tissue 4. Blister forms and breaks open in water, larvae released, enter copepod 3. Female migrates t subcutaneous tissue (~ year)

Phylum Nematomorpha “thread body” - horsehair worms free-living as adults parasitic in arthropods as juveniles Once included with the Nematodes larva Pseudocoelomates, no functional digestive system adult

Phylum Kinoryncha “moveable snout” Segmented body with recurved spines Live in marine mud sediments

Phylum Priapulida “the phallus” Cold water carnivorous marine worms Burrow head-up in marine mud sediments

Phylum Loricifera Have a circular lorica Live among grains of marine gravels

Clade Panarthropoda Phyla with Arthropod Affinities Ph. Arthropoda Ph. Onycophorana Ph. Tardigrada

Phylum Onychophora “velvet worms” • non-jointed walking legs (lobopods) • claw-like processes on appendages • chitinous cuticle (also an arthropod trait) • tracheal system with spiracles • open circulatory system (hemocoel) • large brain

VORACIOUS PREDATORS Sticky slime and toxic saliva

Phylum Tardigrada “slow stepper” • Non-jointed walking legs (lobopods) • Claw-like processes on appendages • Non-chitinous exoskeleton • Body cavity = hemocoel • Rudimentary segmentation • Mouth with sucking pharynx and stylets • Undergo cryptobiosis • Teeny and very cute