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 Sheldon Brook |
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| Stream code: | PSR_ShldBrk_649 |
| Basin: | Passumpsic River |
| State or Province: | Vermont |
| Country: | USA |
| Latitude: | 44.504503 |
| Longitude: | -71.987686 |
| School: | Lyndon High School 2 |
The following are the most common invertebrates collected from this stream site.
Baetis
- 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.
Simuliidae
- 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.
Chironomidae
- 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.
Hydropsychidae
- 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.
Leuctra
- 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.
Ceratopsyche
- Order
- Trichoptera
- Family
- Hydropsychidae
- Genus
- Ceratopsyche
Ceratopsyche has a
forked foretrochantin. The foretrochantin is the projection at the uppermost portion of the foreleg. The leg may need to be pulled away from the body to expose this feature.
Ceratopsyche have a
large pair of sclerites underneath the prosternum. Note: the large single sclerite is the prosternal plate. Biologists have gone back and forth between lumping this genus into
Hydropsyche and splitting it back out. ITIS currently lists it as a genus (Feb 2013) but we are aware of a recent paper that lumped it under
Hydropsyche.
Glossosomatidae
- 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.
Drunella
- Order
- Ephemeroptera
- Family
- Ephemerellidae
- Genus
- Drunella
- Tied fly
- Bluewinged Olive Dun
The mayfly Drunella is distinguished by its large femoral “biceps;” these femora have tubercles on the leading margins. Gills are present on segments 3-7.
Hexatoma
- Order
- Diptera
- Family
- Tipulidae
- Genus
- Hexatoma
This Tipulidae can be identified by the swollen 7th abdominal segment. The swelling is bulbous and frequently as much as 2X abdominal diameter in preserved specimens.
Optioservus
- 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.
Diptera
- 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.
Stenelmis
- Order
- Coleoptera
- Family
- Elmidae
- Genus
- Stenelmis
The larvae of
Stenelmis, as in
Ordobrevia, have a sternum on the ventral side of the pronotum. The main difference between the two genera is in the antennae the second segment is less than twice as long as the first in
Stenelmis.
The adult Stenelmis has a clear separation between the thorax and abdomen as well as a more distinctly separate head as compared to other genera.
Click here to see pictures of the sternum and
antennae-
Dicranota
- 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.
Dolophilodes
- Order
- Trichoptera
- Family
- Philopotamidae
- Genus
- Dolophilodes
Blepharicera
- Order
- Diptera
- Family
- Blephariceridae
- Genus
- Blepharicera
- Common name
- net-winged midges
This dipteran is characterized by six prominent "suction cups" on its ventral side and has tufts on the sides of abdominal sections.
Image of the ventral side.
Siphlonuridae
- Order
- Ephemeroptera
- Family
- Siphlonuridae
- Genus
- Siphlonurus
- Common name
- The Gray Drake
- Tied fly
- Gold-ribbed Hare's Ear
This family has gills on all abdominal segments. The labrum does not have a deep notch, and maxillae do not have pectinate spines. They have posterolateral spines on their last abdominal segment.
Click to view the spines on the last abdominal segment, unlike those found in Baetidae.
Agnetina
- Order
- Plecoptera
- Family
- Perlidae
- Genus
- Agnetina
Agnetina nymphs have cylindrical, striped abdomens. Like other Plecoptera, they have 2 tails and 2 claws on each tarsus. This genus has three black dots (ocelli) on the top of the head. Click to see the
three ocelli on the dorsum of the head (3 black dots at joint with the pronotum). This stonefly is characterized by the
filamentous gills located in the "armpits". Another important feature is the paraglossae and glossae extending different lengths. The
occiput has a transverse row of evenly spaced little hairs.
Agnetina has another row of evenly spaced hairs on the posterior edge of
abdominal segment 7.
Brachycentrus
- Order
- Trichoptera
- Family
- Brachycentridae
- Genus
- Brachycentrus
- Common name
- The Olive Dun Caddis
- Tied fly
- Deer Hair Caddis
These larvae are typically found with their legs extended out of their case for feeding. The cases are square in cross section and made of plant materials. Brachycentrus has 2 large sclerites on the metanotum. In fresh samples (preserved for less than one week) these organisms often have a pale green tint; live specimens are a more vivid green.
Hydropsyche
- Order
- Trichoptera
- Family
- Hydropsychidae
- Genus
- Hydropsyche
- Common name
- spotted caddis
- Tied fly
- dark cahill
Hydropsyche are net-spinning caddisflies and share most characteristics with other members of the Hydropsychidae, including the
Ceratopsyche.
Hydropsyche are distinguished from
Ceratopsyche by the presence of scale hairs and minute spines on the three most posterior abdominal segments.
More information on the Ceratopsyche can be found here.
Image of the sclerites in the intersegmental folds.
Sheldon Brook
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