Centennial Brook

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Streams logo web.jpg Centennial Brook
Stream code:WR_CeBrk_259
Basin:Winooski River
State or Province:Vermont
Country:USA
Latitude:44.48485
Longitude:-73.184015
School:St. Michael's College


The following are the most common invertebrates collected from this stream site.

Chironomidae

Chironomidae.jpg
Order
Diptera
Family
Chironomidae


Common name
Nonbiting midge
Tied fly
Griffith's Gnat
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 caddisfly family Philopotamidae.

More information on Philopotamidae.




Simuliidae

Simuliidae.jpg
Order
Diptera
Family
Simuliidae


Simuliidae appear rather like bowling pins with heads. Relatively speaking, we collect few members of this family and have we have not identified them past family at this point.

Click here for a close up image of the heads.




Diptera

Diptera Pupae.JPG
Order
Diptera



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




Oligochaeta

Oligochaeta.jpg



Common name
aquatic earthworms; black worms
Aquatic earthworms lack legs and are characterized by having 20 or more segments. Unlike leeches, they lack a suction disk. We collect members of two or more orders in this class as small numbers of stream sites and they are rarely numerous. They are more common at pond and lake sites.

Image of the 20 or more segments.




Hydropsychidae

Hydropsyche.jpg
Order
Trichoptera (caddisfly)
Family
Hydropsychidae


Common name
net spinning caddisfly
Tied fly
Emergent Sparkle Pupa, Vermont Hare's Ear
This family of net-spinning caddisflies is very abundant at several sites. They are important filtering collectors and are quite common at urban and agricultural sites where particles of organic material can be important food resources. Genus-level identification is possible for mature specimens and we will include the genera we found at your site if possible.

When using the key, some features that are challenging to see are the forked trochantin and the paired sclerites in the folds between segments. Other, more easily seen key features include filamentous gills on the abdominal segments and the sclerotization of the dorsal surfaces of all three thoracic segments. Keep in mind that with smaller or more immature specimens, genus-level ID may not be possible.

Commonly found genera include Cheumatopsyche, Ceratopsyche, and Hydropsyche. Less commonly, we have found Arctopsyche and Potamyia.

Images of the forked trochantin and the paired sclerites.




Asellidae

Isopodaasellidae2.jpg
Order
Isopoda
Family
Asellidae


Common name
sow bugs
These aquatic sow-bugs have seven pairs of legs and a dorso-ventrally flattened body. They have two pairs of antennae; one pair is much longer than the other pair.

Images of the body and the two pairs of antennae.



Ceratopogonidae

Ceratopogonidae.jpg
Order
Diptera
Family
Ceratopogonidae


Common name
biting midges
Members of this family look like very straight Chironomidae. They are very long and thin with a distinct head capsule and no prolegs. Some in the lab call them 'bamboo sticks' with eyes.

Image of the distinct head capsule.




Dicranota

Dicranota cover.jpg
Order
Diptera
Family
Tipulidae
Genus
dicranota


Dicranota can be distinguished by the two tails and their comb feet. There are usually 5 pairs of prolegs on the abdomen with combs on them. In addition, the posterior portion of the abdomen often has a slight swelling.

Image of the prolegs.




Physidae

Physidae.jpg
Family
Physidae


Members of the family Physidae belong in the class of Gastropoda. Members contain a single, coiled shell with a left handed spiral going counterclockwise. Belonging to the family of aquatic pulmonates, members breathe air using a structure similar to a lung.

Images of the family Physidae, the class of Gastropodaand a shell with a left-handed spiral.




Aeshnidae

Aeshna cyanea Small.jpg
Order
Odonata
Family
Anisoptera


Common name
Darner
Tied fly
Carey Special
All dragonflies have five points sticking out from the back end. Members of this family of dragonflies are distinctly long as can be seen in the photograph. Other common families tend to be a wider and flatter. If you pull out on the mouthparts under the head you'll see that they look flat in side view. If they look spoon-shaped then it is from a different family. Like other Odonata, members of this family have four wingpads. Like members of the sub-order Anisoptera, the abdomen terminates in five points. The prementum and palpal lobes of this dragonfly are flat when viewed from side.

Images of the four wingpads, the abdomen, the prementum and palpal lobes, and a view from the the side.



Planorbidae

Planorbidae.jpg
Family
Planorbidae


Common name
Ram's horn snail
Members of the family Planorbidae belong in the class of Gastropoda. The shell of many Planorbidae is flat and dextral, or right-turned. Belonging to the largest family of aquatic pulmonates, members breathe air using a structure similar to a lung.

Images of the family Planorbidaeand class Gastropoda.




Elmidae

Elmidae Larvae.jpg
Order
Coleoptera
Family
Elmidae


Common name
riffle beetle
We very commonly find 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, Macroychu, Optioservus, Phanocerus, Promoresia, and Stenelmis.

Images of the adult and larval riffle beetles.

More information on Dubiraphia, Macronychus, Optioservus, Phanocerus, Promoresia, and Stenelmis.




Tipula

Tipula cover.jpg
Order
Diptera
Family
Tipulidae
Genus
Tipula


This genus of Tipula is rather large as compared with other genera. Tipula larvae are generally dark brown and have creeping welts.