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Macroinvertebrates home

Streams project

 

Sheldon Brook

These are the most common macroinvertebrates identified from samples from Sheldon Brook.

Click on images to zoom in. 

ORDER: Ephemeroptera
FAMILY: Baetidae 
GENUS: Baetis 

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. SMC

ORDER: Diptera
FAMILY: Simuliidae

Simuliidae appear  rather like bowling pins with heads.  We have not identified them past family at this point, but it is in the long-term plan.

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: Trichoptera
FAMILY: Hydropsychidae

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

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.

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. NABS

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. SMC

 

 


© Aquatic Bioassessment Laboratory, California Digital Reference Collection

ORDER: Trichoptera
FAMILY: Glossomatidae

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.

ORDER: Ephemeroptera
FAMILY: Ephemerellidae
GENUS:
Drunella

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

ORDER: Diptera
FAMILY: Tipulidae
GENUS:
Hexatoma

This Tipulidae can be identified by the swollen 7th abdominal segment.

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 scutellum observable in the dorsal view.
SMC

 

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: 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. SMC

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. SMC

 

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.


ORDER: Diptera
FAMILY: Blephariceridae
GENUS: Blepharicera

This Diptera is characterized by six prominent "suction cups" on its  ventral side and has tufts on the sides of abdominal sections.  SMC

ORDER: Ephemeroptera
FAMILY: Siphlonuridae
 

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, unlike that of Baetidae.

ORDER: Plecoptera
FAMILY: Perlidae
GENUS: Agnetina

The Agnetina has a rounded abdomen that appears to striped. The key defining characteristic is the three ocelli on the dorsum of the head (3 black dots at joint with the prosternum). Like other Plecoptera, it has 2 tails and 2 claws on its tarsi. SMC

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.


NABS
ORDER: Trichoptera
FAMILY: Brachycentridae 
GENUS: Brachycentrus

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.

 


 

ORDER: Trichoptera
FAMILY: Hydropsychidae
GENUS: Hydropsyche

Hydropsyche share most characteristics with Ceratopsyche, including the sclerites in the intersegmental folds. Hydropsyche are distinguished from Ceratopsyche by the presence of scale hairs and minute spines on the three most posterior abdominal segments. SMC

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
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