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Site codes explained and mapped (under mapping resources tab) |
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Mud CreekThese are the ten most common macroinvertebrates identified from samples from Mud Creek. |
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ORDER: Trichoptera 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
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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. |
ORDER: Diptera
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: Coleoptera The true "water penny" is commonly found in the waters sampled. Psephenus has a rounded shape with relatively smooth edge. The false water penny, whose edges are serrated, has a more oval appearance. The gills on the ventral surface are found only in the true water pennies. SMC Another genus encountered in this family is Ectopria.
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This mayfly has either two or three cerci ("tails") and a unique head shape. Its gills are oval shaped and insert dorsally. Commonly encountered genera include Acerpenna, Baetis, and Pseudocloeon. |
ORDER: Trichoptera 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. SMC |
ORDER:
Ephemeroptera This mayfly has unique long hairs on its forelegs as the main distinguishing characteristic (allowing anyone keying to move through quickly). Carefully observe the limbs because such hair can be matted down and therefore hidden in preserved wet specimens. The body of Isonychia is slim and "minnow-like" when observed dorsally. In specimens we collected, they were commonly brown and substantial in length and width as compared to the very common Baetidae. Some individuals are immature, but upon closer inspection one can see the setae on the forelegs. |
ORDER: Diptera Like other larvae from the order Diptera, members of the family Tipulidae (crane flies) lack legs. Tipulidae have retracted, difficult-to-see head capsules at one end, and a spiracular disk at the other end. Upon gently cutting the head open, one can see that the mandibles are not parallel to each other, but rather move against each other. The genera we've encountered include Antocha, Dicranota, Hexatoma, Limnophila, Molophilus, Pedecia and Tipula. |
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ORDER: Ephemeroptera 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.
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ORDER: Ephemeroptera 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.
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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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