Mud Creek 731

Mud Creek 731

Stream code:	MR_MudCrk_731
Basin:	Missisquoi Basin
State or Province:	Vermont
Country:	USA
Latitude:	44.95342
Longitude:	-72.31878
School:	United Christian Academy

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.

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-

Template:Ordobrevia

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.

Psephenus

Order: Coleoptera
Family: Psephenidae
Genus: Psephenus

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.

Another genus encountered in this family is Ectopria.

Antocha

Order: Diptera
Family: Tipulidae
Genus: Antocha

This small dipteran in the cranefly family is quite common. It is distinguished from most other dipterans we found by the 'creeping welts' that appear as prominent dark stripes along the abdomen. The dark head is usually partly exposed; however, it can be pulled back into the thoracic cavity during preservation.

Heptageniidae

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:

Leptophlebiidae

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.

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.

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.

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.

Maccaffertium

Order: Ephemeroptera
Family: Heptageniidae
Genus: Maccaffertium

Common name: The March Brown
Tied fly: March Brown

This genus of Heptageniidae is distinguished by its gills on the seventh abdominal segment, which are reduced to slender filaments. Gills on segments 1-6 are truncated.

Images of the slender filaments, and the truncated gills.

Heptagenia

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.

Paraleptophlebia

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.

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.

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.

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.

Neophylax

Order: Trichoptera
Family: Uenoidae
Genus: Neophylax

Common name: Fool's Caddis
Tied fly: Peeping Caddis

Neophylax are characterized by having a sclerotized pronotum and mesonotum. They build a case of coarse sand grains often with a pair of latteral pebbles or "ballast stones". The larvae are rather stout and the head is scrunched in between the limbs. The anal hooks are attached directly to the abdomen and they rarely come out of the case when preserved. On the ventral surface of the abdominal segments, one can see darkened ovals, known as the chloride epithelia. Like the Limnephilidae, they have a prosternal horn, though it can sometimes be small. Also, they have a dorsal hump and two lateral humps on the first abdominal segment- be careful! Often times, these features can be squished down or damaged in the sampling process. A larva removed from it's case is shown here.

The feature that distinguishes Uenoidae from Limnephilidae is the mesonotum: on either side of the midline, the anterior margin is notched.

Because our samples were taken in summer, we found large numbers of Neophylax pre-pupae. We anticipate that there will be fewer present in the streams in late September and many of those sampled will be at the pupal or adult stage. Samples taken in October would tend to have more empty cases.

Oligochaeta

Common name: aquatic earthworms; black worms

Aquatic earthworms lack legs and are characterized by having 20 or more segments. Unlike leeches, they lack a suction disk. We collect members of two or more orders in this class as small numbers of stream sites and they are rarely numerous. They are more common at pond and lake sites.

Image of the 20 or more segments.

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.

Athericidae

Order: Diptera
Family: Athericidae

Common name: water snipe flies

Members of the family Athericidae have wrinkled bodies with prolegs on the ventral side. Their mandibles- which can be seen by carefully cutting the head open- move parallel to each other. On the end of their abdomen there are two lobes fringed with setae. Our collections include just the single genus Atherix.

Image of the two lobes of the abdomen.

Ectopria

Order: Coleoptera
Family: Psephenidae
Genus: Ectopria

False water pennies are less circular than true water pennies, and come to a blunt point at the back end. They appear to have serrated edges and lack gills.

Another genus encountered in this family is Psephenus.

Acerpenna

Order: Ephemeroptera
Family: Baetidae
Genus: Acerpenna

Common name: Tiny blue-winged olive

This genus is can be identified by the costal process, or projection, distal to the hind wing pad. Gill 7 is slender and may be pointed at the end. The antennal scape and pedicel have a few scattered setae (hairs).

Image of the antennal scape. A ventral view can be seen here.

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.

Libellulidae

Order: Odonata
Family: Libellulidae

Common name: Skimmer

These dragonfly larvae (sub-order Anisoptera) can be distinguished from damselfly larvae (sub-order Zygoptera) by their more robust bodies and an abdomen that ends in five 'spikes' as opposed to three gills. The family Libellulidae is characterized by their spoon-shaped mouthparts.They are distinguished from the other family with this trait, Cordulegastridae, by the small rounded teeth on the edges of their palpal lobes.

Images of the spoon-shaped mouthparts, and the small, rounded teeth.

Aeshnidae

Order: Odonata
Family: Anisoptera

Common name: Darner
Tied fly: Carey Special

All dragonflies have five points sticking out from the back end. Members of this family of dragonflies are distinctly long as can be seen in the photograph. Other common families tend to be a wider and flatter. If you pull out on the mouthparts under the head you'll see that they look flat in side view. If they look spoon-shaped then it is from a different family. Like other Odonata, members of this family have four wingpads. Like members of the sub-order Anisoptera, the abdomen terminates in five points. The prementum and palpal lobes of this dragonfly are flat when viewed from side.

Images of the four wingpads, the abdomen, the prementum and palpal lobes, and a view from the the side.

Veliidae

Order: Hemiptera
Family: Veliidae

This family of Hempitera actually lives on the surface of the water, but can sometimes float into the net while taking benthic samples. Members of the family Veliidae are characterized by the claw of the foreleg; it is inserted before the apex. Also, its hind leg has a beautiful fan of hydrofuge hairs.

Click here to see the claw inserted before the apex and the fan of hydrofuge hairs.

Mud Creek 731

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