ZOO 115 Invertebrate Zoology Nematoda Phylum Nematoda n

ZOO 115 Invertebrate Zoology Nematoda

Phylum Nematoda n n n Common name: round worms >20, 000 species. Mostly widespread and abundant of all metazoans n n 90, 000 worms in a decomposing apple. Marine and freshwater benthos, soil, parasites on plants and animals hooge. developmentalbiology. com/meiofauna/media

Phylum Nematoda - Anatomy /creatures. ifas. ufl. edu/nematode n n n Most freeliving <2. 5 mm in length. Some parasites 50 cm in Nerve> cords length. Body is cylindrical with a. Ovaries pseudocoel Complex cuticle n n Must molt (Ecdysis) Anterior end is radially symmetrical but the rest of the body has bilateral symmetry Digestive tract Excretory canal

Phylum Nematoda - Head Region Nervous system /creatures. ifas. ufl. edu/nematode n n Ring-like brain Sensilla n n n Chemosensory Males also have them near the anus Sensilla /creatures. ifas. ufl. edu/nematode Brain Dorsal, ventral and lateral nerve cords www. unice. fr/LEML/cours. JDV/images/biologie/

Phylum Nematoda - Head Region 3 to 6 lips n 3 -6 lips at the mouth n Buccal Cavity varies depending on prey n n n Bacteria - no teeth or stylet Plant root - stylet Carnivore - small teeth and sometimes stylet Intestine - large hooklike teeth Muscular pharynx /creatures. ifas. ufl. edu/nematode Stylet - like a Hypodermic needle Pharynx Buccal Cavity

Phylum Nematoda - Digestive tract /creatures. ifas. ufl. edu/nematode n n n Foregut (buccal cavity and pharynx shown earlier) Midgut -Intestine Hindgut - Rectum /creatures. ifas. ufl. edu/nematode Anus Cuticle Rectum Intestine

Phylum Nematoda – Excretion n Excretory glands and canals thought to be involved in: n n Osmoregulation Ionic regulation Excretion of waste metabolites Ammonia secreted through body wall www. ustboniface. mb. ca/cusb/abernier/Animaux/Pseudocoelom Nerve cords Ovaries Longitudinal Muscles Digestive tract Excretory canal

Phylum Nematoda – Musculature n Longitudinal muscles only! www. ustboniface. mb. ca/cusb/abernier/Animaux/Pseudocoelom Nerve cords Ovaries Longitudinal Muscles Digestive tract Excretory canal

Phylum Nematoda - Reproduction n n Separate sexes - usually Males have hook-like posterior n n www. apsnet. org/education/Lessons. Pl ant. Path/Pine. Wilt/images/ Testis Male Rectum - Cloaca n n n Spicule Reproduction Digestive waste Spicule for sperm transfer n Retractable Rectum - Cloaca creatures. ifas. ufl. edu/nematode/

Phylum Nematoda - Reproduction creatures. ifas. ufl. edu/nematode/ n Females n n Ovaries Eggs Vulva Seminal Receptacle Ovary Seminal recepticle Eggs Vulva creatures. ifas. ufl. edu/nematode/

Phylum Nematoda - Parasites: Racoon parasite Roundworm Life Cycles Baylisacaris procyonis www. extension. umn. edu/distribution/cropsystems/images Plant parasite Human Parasite Ascaris lumbricoides