DIVERSITY OF OLIGOCHAETES

OLIGOCHAETA & HIRUDINOMORPHABy The HelpersPAULA MARIE M. LLIDOJEDIDIAH J. QUIDETEARL JUDD C. SULLANO

DIVERSITY OF OLIGOCHAETA

DIVERSITY OF OLIGOCHAETESCOMMON AQUATIC TAXACOMMON TERRESTRIAL TAXA

Whats the difference?

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Small, delicateBody walls transparentMost abundant in shallow water - in rocks and driftsClitella secrete little or no albumen

COMMON AQUATIC TAXA

FAMILYAeolosomatidaeNaididaeTubificidaeLumbriculidae

5Fig. 17.18

FAMILYGlossoscolecidaeLumbricidaeMegascolecidaeMonoligastridae

PREFER - Rich soilHABITAT- Acid soil

COMMON TERRESTRIAL TAXA

WHAT ARE THE BENEFITS GIVEN BY THE EARTHWORMS?

Class Oligochaeta External Parts

8Fig. 17.12b

Oligochaeta Nervous System

9Fig. 17.15

CLASS HIRUDINOMORPHA

CLASS HIRUDINOMORPHALeeches and closely related wormsMarine, mostly freshwater, a few terrestrial species (restricted to moist environments)Lack chaetaeHave a fixed number of segments (typically 33)All have a posterior sucker for adhering to prey or substratumMost have an anterior sucker as well

Blood-sucking ectoparasites or carnivores

1 cm to 30 cm long (Haementeria, giant Amazonian leech)

Black, brown, olive, or red in colorMay have striped / spotted patterns

Typically inhabit stagnant or slow moving freshwaterEstimate in mud during periods of drought

Hirudo medicinalis

13Fig. 17.21

Nervous SystemSimilar to other annelids

Fusions of ganglia in the sucker regions

Posses ocelli

Posses sensory papillaeProjecting discs consisting of many sensory cellsTypically found dorsally, in rows, on one annulation of a particular segment

Sense organs mainly used for prey detection, and respond to:Moving shadows and water-pressure vibrations in fish leechesChemicals from body fluids such as oils, sweat, and bloodWavesTemperature differences

Body FormDorsoventrally flattenedTapered at anterior endSuckersAnterior - smaller and surrounds mouthPosterior is disc-shaped; anus located directly anterior

Annulations that dont accurately depict segmentsNumber of annulations per segment varies

Clitellum is only conspicuous during reproduction

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