Phyla Nematoda, Tardigrada and Onycophora lab notes

PHYLA NEMATODA, TARDIGRADA, ONYCHOPHORA


Phylum Nematoda
FEATURES
 Cuticle made of collagen
 Incremental growth (molt cuticle)
 Both ends taper to a point


SPECIES
Ascaris lumbricoides
IDENTIFY
 Labia
 Mouth
 Anus
 Intestine
 Testes
 Ovaries
 Life cycle!!


Ascaris lumbricoides – male c.s.
IDENTIFY
 Cuticle
 Intestine
 Lumen of intestine
 Vas deferens (sperm duct used to move sperm from testes to cloaca)
 Pseudocoel
 Longitudinal muscles


Ascaris lumbricoides – female c.s.
IDENTIFY
 Cuticle
 Intestine
 Lumen of intestine
 Pseudocoel
 Longitudinal muscles
 Ovary and uterus



Necator americanus (hook worm)

, FEATURES
 Females larger than males
 Males have copulatory bursa
 Pair of dorsal and pair of ventral cutting plates surrounding the anterior margin of
buccal capsule (mouth)


Ancylostoma caninum (dog hook worm)
 see N. americanus for structures


Enterobius vermicularis (pin worm)
FEATURES
 Males 1-4mm, females 8-13mm
 Basal esophageal bulb (swollen cuticle at head end)
 Slender, sharp-pointed tails (especially in females)


Trichinella spiralis (trichinelloid worms)
FEATURES
 Calcified cysts in striated muscle tissues
 Males 1.4-1.6mm, females about double this
 Causes Trichinosis (cysts transmitted from pig to man via undercooked pork)
 Life cycle!!


Onchocera volvulus – female
FEATURES
 Worms knotted together in pairs or groups in subcutaneous tissue
 Encapsulated in fibrous tissue
 Adult females 230-500 mm, males 16-42mm
 Microfilariae 220-360 µm
 Life cycle!!
 Causes onchocerciasis (river blindness)


Dirofilaria immitis (heartworm)
 Life cycle!!




Phylum Tardigrada

Hypsibius – water bear