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 Ryder Brook |
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| Basin: | Lamoille River |
| State or Province: | Vermont |
| Country: | USA |
The following are the most common invertebrates collected from this stream site.
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.
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.
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.
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.
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-
Cheumatopsyche
- Order
- Trichoptera
- Family
- Hydropsychidae
- Genus
- Cheumatopsyche
Cheumatopsyche has a
forked foretrochantin (as does
Ceratopsyche). The foretrochantin is the projection at the uppermost portion of the front leg closest to the head. The leg may need to be pulled away from the body to expose this feature.
Cheumatopsyche have a small or inconspicuous
pair of sclerites under the prosternal plate that are difficult to see. Contrast that with the
larger pair of sclerites found on Ceratopsyche. To access sclerites, it's best to gently pull the pronotum and mesonotum in opposite directions. Note: the large single sclerite is the prosternal plate.
Cheumatopsyche have only 2 types of
hair on the abdomen: long thin plain hairs and thicker club hairs, which are narrow close to the body and widen out at the distal end. Paired sclerites on the ninth abdominal segment are notched.
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.
Acroneuria
- Order
- Plecoptera
- Family
- Perlidae
- Genus
- Acroneuria
Acroneuria are among the most common Perlid stoneflies that we find. The larvae have a close-set postocular fringe consisting of thick spinules. They have three ocelli, and a yellow m-shaped mark in front of the middle ocellus. The bases of their cerci have thick, silky setae.
The postocular fringe can be seen here. Look in front of the three ocelli for the yellow m-shaped mark. Focus where the cerci meet the body to see the thick, silky setae.
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.
Chimarra
- 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.
Ryder Brook
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