lochotrophozoa III ecdysozoa I

1. lochotrophozoaIIIecdysozoaI BIOL240.002 Zoology 20 October 2014

2. Annelid and Sipunculan Phylogeny Fig. 11.1 p. 215

3. Phylum Annelida“little rings”—~15,000 (12,738) spp. segmented worms • Metamerism—segmentation with repetition of major muscle groups, nephridia, minor blood vessels, ganglia and nerves, etc. • Septa confine hydrostatic movement to regions of the body • Circular and longitudinal muscle groups • Most with bristle-like setae • Terminal mouth and anus • Schizocoelouseucoelom • Closed circulatory system • Dorsal vessel: anterior flow • Ventral vessel: posterior flow • Ventral nerve cord, dorsal anterior brain Fig.11.3 p. 216

4. Annelid and Sipunculan Phylogeny 11,145 spp. 8 orders 1344 spp. 6 orders 249 spp. 5 orders Which classes are paraphyletic, as shown? 205 spp. 4 orders Fig. 11.1 p. 215

5. Class Polychaeta—polychaetes“many long hairs” • Marine crawlers, burrowers, or tube dwellers • Fleshy parapodia • Highly developed eyes and statocysts on head • Bundles of setae on parapodia • Jaws or ciliated tentacles • Mostly dioeciousspawners Fig. 11.2 p. 216 Fig. 11.5 p. 218 Fig. 11.8 p. 219

6. The Palolo Worm of American Samoa • Epitoke—seasonal gamete-producing segments • Break free of atoke segments for spawning • Just a few hours in Oct./early Nov. • After midnight • Dependent on moon cycle • Sometimes twice in a year • Eaten raw, fried in oil, baked in loaves or on pizza • Fishy, salty taste Fig. 11.9 p. 219

7. Class Oligochaeta—oligochaetes“few long hairs” • Mostly terrestrial or freshwater • A few marine or parasitic spp. • Few setae, in pairs • Simultaneous hermaphrodites • Clitellum: Swollen band involved in reproduction • Mucus for sperm transfer • Chitinouscocoon around eggs • Direct development Fig. 11.15 p. 223

8. Earthworm Reproduction Fig. 11.18 p. 225

9. Class Hirudinea—leeches“leeches” • Mostly freshwater • Flattened with narrow metameres, generally aseptate and lacking setae • Few anterior septa and setae in one group • Coelom filled with connective tissue and muscle • Predators or blood-sucking parasites • 3 jaws • Anterior and posterior suckers • Salivary anticoagulant in blood parasites • Simultaneous hermaphrodites • Copulate • Direct development in egg cocoons Fig. 11.21 p. 227

10. Two former phyla relegated to Polychaeta due to phylogenetic analyses • Former Echiura • Spoon worms • ~140 (205) spp. • Feed using ciliated proboscis • Trochophore larva • Males inhabit uterus of female in one sp. • Former Pogonophora • Beard worms • ~150 (53) spp. • Absorb food and live off bacterial mutualists • No digestive tract “viper tail” Figs. 11.13 and 11.14 p. 222 “beard bearer” Fig. 11.12 p. 221

11. Phylum Sipuncula“little siphon”—~250 (205) spp. peanut worms • Marine burrowers • Retractibletentacledintrovert • U-shaped coiled gut with anus on side, just behind introvert • Hydrostatic schizocoelouseucoelom • Ventral nerve cord • Two nephridia • Asexual fission and regeneration • Dioecious with external fertilization • One sp. is monoecious • Most have trochophore larva • Some direct • Some with second worm-like pelagosphera larvae Fig. 11.23 p. 228

12. Ecdysozoa

13. Ecdysozoan Phylogeny Fig. 12.1 p. 233

14. Phylum Nematoda“thread”—~12,000 (3455) spp. roundworms • Broadly distributed among marine, freshwater, and terrestrial habitats (free-living spp.) and plant and animal hosts (parasites) • Potentially much more diverse than species list suggests • Hypodermis secretes collagen cuticle antagonistic to longitudinal muscles • False body cavity • Complete digestive tract • Eutely • Ex: Caenorhabditiselegans, 959 cells • Nerve ring anteriorly and dorsal and ventral nerve cords • Dioecious; male has copulatory spicules for internal fertilization • Oviparous with direct development • Four molts of juvenile cuticle Fig. 12.2 p. 234 Fig. 12.3 p. 235

15. p. 236 Fig. 12.7 p. 238

16. Phylum Nematomorpha“thread form”—~320 (361) spp. horsehair or Gordian worms • Free-living aquatic adults • Juveniles parasitize hemocoels of terrestrial arthropods • Insects, spiders, pillbugs, hermit crabs • Some have second invertebrate host • Can induce water-finding behavior when ready to emerge from host • Cuticle, false body cavity, and longitudinal muscles • Vestigial digestive tract • Absorb nutrients, even as free-living adults • Ventral nerve cord • No organs for gas exchange, circulation, or excretion • Dioecious • Internal fertilization and oviparity • Nematomorph larva penetrates new host Fig. 12.10 p. 239

17. Phylum Kinorhyncha“moving beak”—179 (157) spp. kinorhynchs • Marine interstitial animals • 13 zonites: retractible proboscis, neck, and 11 body zonites with scalid spines • Anchors and chemo-/ mechanoreceptor sense organs • Chitinous cuticle, reduced true body cavity, and longitudinal muscles • Crawl about using introvert • Brain and ventral nerve cord • Two protonephridia • Dioecious • Internal fertilization • Oviparous with egg cases • 11-segmented juvenile molts 6 times, adding two zonites Fig. 12.11 p. 240

18. Phylum Priapulida“phalluses”—16 (19) spp. priapulids or penis worms • Marine burrowers • Retractibleintrovert feeds on small prey • Terminal anus • Hollow caudal appendages may be respiratory or chemosensory • Ventral nerve cord • Protonephrida • Dioecious with external fertilization • Some brood eggs • Larvae have lorical coverings (similar to adult Loricifera) Fig. 12.12 p. 240

19. Phylum Loricifera“coreselet bearer”—~100 (22) spp. loriciferans • Marine interstitial animals • <400 m • Cuticle forms plated loricainto which head can retract • Scalids on head • Pseudocoelom • Pair of protonephridia • Dioecious with internal fertilization • Higgins larva has adhesive toes • In some spp., larvae reproduce via parthenogenesis Fig. 12.13 p. 240

20. Phylum Onychophora“claw bearer”—~70 (167) spp. velvet worms • Terrestrial tropical animals • Metameric and hydrostatic • 13-43 pairs of hydrostatic lobopodswith chitinous claws • Antennae with eyes at bases • Slime glands of oral papillae capture prey • Open circulatory system • Coxal glands • Dioecious with spermatophores deposited on female’s back • One Australian sp. inserts spermatophores attached to male’s head • Placentally or aplacentally viviparous or oviparous • Direct development Fig. 12.14 p. 240

21. Phylum Tardigrada“slow step”—~900 (1018) spp. water bears or moss piglets • Microscopic animals that live in water film on mosses and lichens • Four pairs of clawed legs • Piercing pair of stylets and sucking pharynx • Ventral nerve cord, dorsal brain • True coelom • 3 excretory Malpighian tubules open to gut • Dioecious • Copulate or external fertilization of eggs in shed cuticle of female • Some parthenogenic • Direct development • Cryptobiosis: dehydrate (to 3% water) in a tun for up to 10 years Fig. 12.15 p. 240 HANDOUT

22. HANDOUT—Jönnson and Bertolani

23. HANDOUT—Guidetti and Jönnson