Snipe Island Brook

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Streams logo web.jpg Snipe Island Brook
Stream code:WR_SIBrk_714
Basin:Winooski River
State or Province:Vermont
Country:USA
Latitude:44.42312
Longitude:-72.94413
School:Saint 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.




Heptageniidae

Dic 2008 F Heptageniidae.jpg
Order
Ephemeroptera
Family
Heptageniidae


Common name
flatheaded mayfly
Tied fly
Light Cahill, Wingless Pale Evening Dun
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

Rhithrogena




Dolophilodes

Dolophilodes.jpg
Order
Trichoptera
Family
Philopotamidae
Genus
Dolophilodes


Dolophilodes stands out in the Philopotamidae family due to its slightly asymmetrical frontoclypeus on the anterior margin and its distinguishable projecting foretrochantin.

Images of the slightly asymmetrical frontoclypeus, and the projecting foretrochantin.




Baetis

Baetis.jpg
Order
Ephemeroptera
Family
Baetidae
Genus
Baetis


Common name
The Little Olive
Tied fly
Sawyer Pheasant Tail Nymph
This mayfly has three "tails" and a unique head shape. Its gills are oval shaped and insert dorsally. More mature nymphs have long, dark wing pads.

Image of the long, dark wing pads.




Leuctra

Leuctra2.jpg
Order
Plecoptera
Family
Leuctridae
Genus
Leuctra


This family of stonefly is fairly slender by stonefly standards. The divergent wing pads are a helpful characteristic. Leuctridae are similar in overall shape to the Capniidae; however, Leuctridae often do not have pleural folds. If they are present, they only extend from abdominal segments 1-7. Leuctra are recognized by abdominal terga with posterior fringes of short hairs and last few segments with longer hairs.

Image of the divergent wing pads.




Chimarra

Chimarra.jpg
Order
Trichoptera
Family
Philopotamidae
Genus
Chimarra


Chimarra are distinguished from the other Philopotamidae by a prominent asymmetrical notch in the frontoclypeus as well as a prominent process on the femur which bears a single hair (seta).

Images of the asymmetrical notch and prominent process.



Heptagenia

Heptagenia.jpg
Order
Ephemeroptera
Family
Heptageniidae
Genus
Heptagenia


Tied fly
Little Graywinged Olive
Heptagenia are easily characterized by their flat head. The claws have just one basal tooth and no denticles (serrated edges). The gill on abdominal segment 7 has multiple fibrils at is base (thread-like structures) and has a single tooth on its claws but is smooth otherwise. Gills on segment 7 are similar to those on all other segments, but may be smaller in size.




Leptophlebiidae

Leptophlebiidae whole.jpg
Order
Ephemeroptera
Family
Leptophlebiidae


Common name
pronggill mayfly
Leptophlebiidae are characterized by a somewhat flattened body and forked elongate gills. Commonly found genera include Habrophlebia and Paraleptophlebia.

Image of the forked elongate gills.




Glossosomatidae

Glossosoma - Whole3.jpg
Order
Trichoptera
Family
Glossosomatidae


Common name
saddlecase caddisfly
Larvae in this family build domed cases made of small rocks, and are often wider at segment 5. The pronotum is covered in dark, sclerotized plates, but there are either no sclerites on the mesonotum, or the mesonotum is unsclerotized with the exception of a few patches. The anal proleg is broadly joined to segment 9; the anal claw has one or more accessory hooks. The pronotal excision is small (approximately 1/3 anterolaterally) to accommodate the coxae.

Commonly encountered genera include Glossosoma and Agapetus.




Paraleptophlebia

Paraleptophlebia.jpg
Order
Ephemeroptera
Family
Leptophlebiidae
Genus
Paraleptophlebia


Common name
The Blue Quill
Tied fly
Blue Quill
Leptophlebiidae have forked, tufted, or fringed gills. Paraleptophlebia typically have labrums less than 1/2 as wide as head anteriorly, which is considered "shallow." There are minute spinules present on posterior margins of abdominal terga 1-10.

Image of the forked, tufted, or fringed gills.




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.




Optioservus

Optioservus (Larvae).jpg
Order
Coleoptera
Family
Elmidae
Genus
Optioservus


The larvae of Optioservus have open coxae, as determined by the straight definition between segments on the ventral side of the pronotum.

The adult Optioservus have a compact appearance, especially the head and thorax. There are also dorsal ridges and a characteristic diamond-shaped sutellum observable in the dorsal view.

Images of the straight definition between segments, the dorsal ridgesand the diamond-shaped scutellum.




Perlidae

Agnetina.jpg
Order
Plecoptera
Family
Perlidae


Common name
The Golden Stonefly Creeper
Tied fly
Connecticut Curler
This stonefly is characterized by the three pairs of filamentous gills located on the sides of all three thoracic segments. It is distinguished from the family Pteronarcyidae by the absence of gills on the abdominal segments. Often, the thoracic terga are brightly patterned as pictured, though this is not always the case. Another important feature is that the paraglossae and glossae extend different lengths.

Images of filamentous gills and the family Pteronarcyidae.

Genera commonly encountered in this family include Acroneuria, Agnetina, and Paragnetina. Less commonly, we have found Perlesta.

Very rarely encountered genera include Neoperla and Hansonoperla. If you believe you have found either of these, please send a specimen our way!




Rhyacophila

Rhyacophila.jpg
Order
Trichoptera
Family
Rhyacophilidae
Genus
Rhyacophila


Common name
Green Caddis
Tied fly
Henryville Special or Glass Bead Caddis
In our lab, Rhyacophila is known as the "Michelin Man" due to its large banded body. It has a very obviously checker-patterned head. It also has terrifying anal claws with large accessory hooks.

Links to images that may be useful if you have a magnifying glass or microscope: Checker-patterned head. Anal claws with large accessory hooks.