Diversity of Benthic Animals Exclusive of Insects Categories
Diversity of Benthic Animals Exclusive of Insects
Categories of Benthic Animals • >1 mm macrobenthos • <. 1 mm microbenthos • Between. 1 and 1 mm meiobenthos
Major Taxonomic Groups of Benthos • Porifera • Coelenterata • Annelida • Platyhelminthes • Mollusca – Hydrozoa – Turbellaria • • Nemertea Gastrotricha Rotatoria Nematoda Nematomorpha Tardigrada Bryozoa – Oligochaeta – Hirudinea – Gastropoda – Pelecypoda Chelicerata Arachnida • Arthropoda – Crustacea – Insecta
Major Functional Groups of Benthos Functional Feeding Groups • Predators • Omnivores • Collectors – Filtering Collectors – Gathering Collectors • Scrapers • Shredders • Piercers Habitat & Behavior • Clinger • Climber • Sprawler • Burrower • Swimmer
Hilsenhoff Biotic Index Water Quality Degree of Organic Pollution 0. 00 -3. 50 Excellent No apparent organic pollution 3. 51 -4. 50 Very good Possible slight organic pollution 4. 51 -5. 50 Good 5. 51 -6. 50 Fair 6. 51 -7. 50 Fairly poor 7. 51 -8. 50 Poor 8. 51 -10. 00 Very poor Some organic pollution Fairly significant organic pollution Significant organic pollution Very significant organic pollution Severe organic pollution 1929 -2011
Porifera (Sponges), c-f • • • Spongillidae (4/5) 30 sp. in U. S. Spicules Reduction bodies Gemmules Filterer
Coelenterata (Cnidaria), prd • Hydrozoa – Hydra (4/5); 11 sp. – Nematocysts – Budding – Sessile – Craspedacusta sowerbii – “Freshwater jellyfish” – Appear very sporadically
Platyhelminthes (Flatworms), prd • Turbellaria (7 -9) – 5 orders – Tricladida and Rhabdocoela – Flattened ventrally – Have a “head” – Reproduce by fission, sexually, both; cocoons – Move on cilia and mucus – Feed with an extended pharynx (living, dead, crushed animal matter)
Nemertea (proboscis worms), prd • Prostoma rubrum (6) common in US • Overlooked; spotty distribution • Proboscis is 2 -3 x body length w/stylet • Hermaphroditic • Regeneration • Habitat- filamentous algae • Forms cysts in adverse conditions • Enemies- larger worms, carnivorous insects, crustaceans
Gastrotricha, c-g • • • Wormlike; 7 genera in FW Puddles, marshes, wet bogs Furca- toe like projections Cuticle- patterned, plates, scales, or spines Move by beating ventral cilia Eat bacteria, algae, detritus Excretion- flame bulbs Eyespots and cilia = sensory Parthenogenetic females
Rotifera, f-prd • • • Originated in FW; 1700 sp. Found widely; 2 classes; Bdelloidea Movement is by peripheral cilia Head, trunk, foot (toes) Digestive- mastax (jaws that rip and tear food) Trophi- toothlike portions of the mastax Tube construction Eyespots, antenna Bdelloids are parthenogenic Desiccation- months or years
Nematoda, c-g, prd • • • Roundworms (9); 1000 sp. FW Whiplike movement Lips- stylet or none Eyespots; tactile receptors Parthenogenetic Survive anaerobic conditions
Nematomorpha, c-g • • Gordian/ Horsehair Worms (9) Immatures internal parasites 10 cm- 70 cm; same diameter Heavy cuticle No food digested Larval disagreements Encyst; penetrate host? Poorly understood ecology
Tardigrada, piercers • • • Strictly aquatic “water bears” < 500 microns long Lichens, liverworts, mosses Liquid materials ingested Sucking pharynx; stylets Sexes separate During dry periods- anabiotic state (4 -7 years) Thick body cuticle Anabiosis, cysts, asphyxy
Bryozoa (Moss Animalcules), c-f • • • Unpolluted waters; 3500 marine sp; 14 FW in US (4) Grapefruit size gelatinous colonies (Faylor Lake) Sessile; do not like bright light; shallow waters Asexual reproduction Polypide
Bryozoa (Ectoprocta) • Plumatella • Pectinatella • statoblast
Annelida (Oligochaeta), c-g • Tubifex; (10)
Annelida (Branchiobdellida), c-g • Commensal on crayfish (on gills and gill chambers and externally on body) • Link between oligochaetes and leeches? • Has a caudal sucker with jaws • No setae • Found in jars of preserved crayfish • 6 Hilsenhoff
Annelida, prd • Hirudinea – Hirudo (6) – Glossiphonia (8)
Annelida (Polychaeta), c-g • Mostly marine (10) • 6 sp. From NA • Manayunkia speciosa
Mollusca (Gastropoda), scr • Gastropoda – Physa (8) – Helisoma (Planorbella) (6) – Pleurocera (6)
Mollusca (Gastropoda), scr • Viviparidae (7) • Valvatidae (2)
Mollusca (Gastropods), scr • Hydrobiidae (8) • Ancylidae (limpets; 7) • Lymnaeidae (7)
Mollusca (Bivalvia), c-f • Pelecypoda – Corbicula (6) – Dreissena (8) – Sphaerium (6)
Mollusca, c-f • Pelecypoda (Bivalvia) – Elliptio (8) – Lampsilis (6)
Aquatic Arachnid Arthropods, prd • Water Mites (e. g. Arrenurus, 6) • Fishing Spiders (e. g. Dolomedes)
Benthic Crustacean Arthropods • • • Cladocera Copepoda Ostracoda Isopoda Amphipoda Decapoda
Cladocera • • • Thoracic and abdominal regions covered by a shell 2 valves Locomotion is “hopping” Feed on algae and Protozoa Leptodora is predacious Ephippia- resting stage
Benthic Copepods • Harpacticoida (8)
Benthic Copepods • Cyclopoida • Calanoida
Ostracoda, c-g • Seed Shrimp (e. g. Cypria, 8) • Cypricercus cf. fasciatus, 8
Isopoda, c-g • Aquatic sow bugs (e. g. Caecidotea, 8)
Amphipoda, c-g • Side swimmers or scuds – Hyalella (8) – Crangonyx (4) – Gammarus (4 -6)
Decapoda, c-g • Crayfish ( Orconectes rusticus) (6) – Procambarus (6) – Cambarus (6)
Prawns and River Shrimps • Glass Shrimp (e. g. Natania)
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