Invertebrate Keys Page 3 - Keys to the Aquatic Biota of the Hawaiian Islands

	CPIE Project		Page A3

Phylum ANNELIDA Segmented worms Tubes of Ficopomatus in lower Inoa`ole Stream, Waimanalo
Three classes of annelids have known representatives in fresh and brackish waters in Hawai`i: Hirudinea, Oligochaeta, and Polychaeta. These are small, worm-like animals (most under 1 cm) which live a cryptic (hidden) or infaunal (buried in soft sediment) existence. However, oligochates (aquatic earthworms) are readily observed by microscopic examination of submerged vegetation and leaf litter from most aquatic environments, and infaunal oligochaetes and polychaetes dominate estuarine sediments. Calcareous tubes of serpulid worms (see left) can be found attached to hard surfaces in some estuarine or brackish waters. Leeches (Hirudinea) inhabit many streams and estuaries, hiding under rocks or attached to prey (such as fishes). A listing of Hawaiian aquatic annelid worms, including references to useful identification materials, is provided elsewhere in CPIE.

Key to Phylum Annelida

35a (21) Namalycastis abiuma from lower Manoa Stream Most segments with paired, lateral projections (parapodia) associated with clumps of setae (very fine, projecting structures shaped like needles, hooks, combs, or blades)
~ Class POLYCHAETA
[83]

35b At most only a few segments at or near the head or tail ends with lateral projections or appendages. Setae present or absent
~ Class OLIGOCHAETA [36]

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36a (35) Small (usually under 1-2 cm), red worms living in tubes of mud at bottom of stagnant pools; when alive, whipping back and forth
~ Family TUBIFICIDAE

36b Animal is a worm, but not as above (Figure 2)
~ other ANNELIDA [88]

leech, Keanuiomanu Stream, Waiaka, Big Island
Figure 2. A typical leech. Note attachment disc at bottom left and faint indication of annulations (much clearer under higher magnification). This species has 3 pairs of eyes on the head.


© 2002 AECOS, Inc. [FILE: inv_02.html]		Annelida
INSTRUCTIONS INDEX REFERENCES	2

	Phylum ANNELIDA Segmented worms Three classes of annelids have known representatives in fresh and brackish waters in Hawai`i: Hirudinea, Oligochaeta, and Polychaeta. These are small, worm-like animals (most under 1 cm) which live a cryptic (hidden) or infaunal (buried in soft sediment) existence. However, oligochates (aquatic earthworms) are readily observed by microscopic examination of submerged vegetation and leaf litter from most aquatic environments, and infaunal oligochaetes and polychaetes dominate estuarine sediments. Calcareous tubes of serpulid worms (see left) can be found attached to hard surfaces in some estuarine or brackish waters. Leeches (Hirudinea) inhabit many streams and estuaries, hiding under rocks or attached to prey (such as fishes). A listing of Hawaiian aquatic annelid worms, including references to useful identification materials, is provided elsewhere in CPIE.
	Key to Phylum Annelida

35a	(21)	Most segments with paired, lateral projections (parapodia) associated with clumps of setae (very fine, projecting structures shaped like needles, hooks, combs, or blades) ~ Class POLYCHAETA	[83]
35b		At most only a few segments at or near the head or tail ends with lateral projections or appendages. Setae present or absent ~ Class OLIGOCHAETA	[36]
		~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
36a	(35)	Small (usually under 1-2 cm), red worms living in tubes of mud at bottom of stagnant pools; when alive, whipping back and forth ~ Family TUBIFICIDAE
36b		Animal is a worm, but not as above (Figure 2) ~ other ANNELIDA	[88]
Figure 2. A typical leech. Note attachment disc at bottom left and faint indication of annulations (much clearer under higher magnification). This species has 3 pairs of eyes on the head.