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Macroinvertebrates home

Streams project

 

Riveras

These are the eight most common macroinvertebrates identified from samples from Riveras.

Click on images to zoom in. 

ORDER: Hemiptera
FAmily: Veliidae
 

This family of Hempitera actually lives on the surface of the water, but can sometimes float into the net while taking benthic samples.

Veliidae is characterized by the claw of the foreleg; it is inserted before the apex. Also, its hind leg has a beautiful fan of hydrofuge hairs.

Hexatoma sp. Tipulidae - photo by Wayne Davis USEPA
US EPA

ORDER: Ephemeroptera
FAMILY: Caenidae

These "small square-gill" mayflies have operculate (plate-like) gills on segment 2 that cover gills on segments 3 to 6. Their bodies are built for crawling, and their heads are held vertically. The genus Caenis is commonly found.

ORDER: Diptera

Pupae from the order Diptera are typically found in small numbers at every site. These can be identified further, but we do not.

 

ORDER: Diptera
FAMILY: Chironomidae

 Midge larvae tend to be the most common macroinvertebrate at our sites.  As with other Diptera, there are no true jointed legs.  Chironomidae do have a pair of prolegs at each end and preserved individuals tend to curl into a 'C'.  Identification past family requires slide-mounted heads.  We have seen philopotamid caddisflies misidentified with the chironomids and we suspect that that happens when samples are being sorted from trays.  Under a microscope, six prominent legs can be seen on members of the family Philopotamidae.

ORDER: Ephemeroptera
FAM
ILY: Heptageniidae

This family of mayflies can be characterized by their distinctly flattened heads and striking resemblance of the character 'Jack Skellington' from the movie 'The Nightmare Before Christmas.' This family can either have two or three cerci (tails).

Commonly encountered genera include Epeorus, Heptagenia, Maccaffertium, and Rhithrogena.

ORDER: Lepidoptera
FAmily: Pyralidae
 

This family of Lepidoptera does not necessarily have filaments on its body, though this one does. It has welts on the bottom of its abdomen, and three pairs of stubby- but still segmented- legs on the thorax.

ORDER: Odonata
SUB-ORDER: Zygoptera
FAMILY: Coenagrionidae
 

These damselfly larvae (sub-order Zygoptera) can be distinguished from dragonfly larvae (sub-order Anisoptera) by their more slender bodies and the presence of three leaf-like gills at the end of the abdomen, seen here and here. The family Coenagrionidae is characterized by its distinctly shaped labium, which may or may not be extended.

ORDER: Coleoptera
FAMILY:
Elmidae

We have found adult and larval riffle beetles. The adults are clearly beetles, but the larvae can be confused with other orders. The forward pointing tooth on the front end of the larvae as described in the key can be a challenge to see, particularly in small individuals.

Larvae are characterized by having a single tarsal claw at the end of their legs, which have 4 segments. Adults, on the other hand, have two tarsal claws at the end of each leg.

Commonly encountered genera include Dubiraphia, Macronychus, Optioservus, Phanocerus, Promoresia, and Stenelmis.

The images are not a substitute for keying, but should serve as an aid in identifying common macroinvertebrates in samples.

Feedback - Partner schools: send us specimens not included above.  Taxonomists: click to email: Declan McCabe
This site is supported by Vermont EPSCoR grant from the National Science Foundation (EPS #0701410).
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