Glossary for the Ephemeroptera of Gunnison County, Colorado

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Glossary for the Ephemeroptera of Gunnison County, Colorado

Updated 26 02 2026

For some old school definitions, chek out Hagen's Glossary.pdf and Say's Explanation of Terms Used in Entomology.pdf

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

B

brunnea - Latin for brown.

Black wing pad (BWP) - Wing pads hold the developing mayfly wings. They turn dark shortly before the mayfly emerges as a subimago or dun. If you are watching live insects in a pan of water, look for BWP nymphs swimming to the surface with puffed up or expanded wingpads. Also watch for animals with a split in the thorax and head, the mayfly may emerge in the next few minutes!

When a key says you need "mature nymphs", these are the best animals for identificaiton. However animals with near full size wing pads are mature enough for most keys.

C

COI - cytochrome c oxidase 1 is a mitochodrial gene used in DNA barcoding. It is about 650 base pairs long. Usually it is sequenced so we can understand the relationships between species. Hopefully in the future we can use this gene to identify species that are difficult to identify under the microscope.

D

dorsal - Back or upper surface of an animal. See ventral.

E

F

G

gills - Used by the mayflies for respiration or gas exchange between their tracheal system and the water. Gills may appear as flat plates or filaments protruding from the mayfly's abdomen. Some mayflies have both flat plates and filamentous gills.

H

I

ITIS - The Integrated Taxonomic Information System http://www.itis.gov/ provides taxonomic information on plants, animals, fungi, and microbes of North America and the world. They are a partnership of U.S., Canadian, and Mexican agencies (ITIS-North America); other organizations; and taxonomic specialists. ITIS is also a partner of Species 2000 and the Global Biodiversity Information Facility (GBIF). The ITIS and Species 2000 Catalogue of Life (CoL) partnership is proud to provide the taxonomic backbone to the Encyclopedia of Life (EOL). [This text was copied from their website on 2 June 2010.] They also assign Taxonomic Serial Numbers.

J

K

L

M

monophyletic - a group of organisms that are closely related. All of their descendants are also related. See See polyphyletic.

macula - spot or dark mark

mtDNA - Mitochondrial DNA is inheritated through the females only. Male mitochondrial DNA is destroyed after fertilization. As a result mtDNA is clonal since it is inherited only through the mother. Mitochondria have an essential role in cellular metabolism through the creation of adenosine triphosphate (ATP). Since ATP is required for energy metabolism, mitochrondrial DNA has a very slow mutation rate. This provides an excellent clock to determine the time since divergence from an ancestral lineage. MtDNA is useful for determing the relative distance between species or populations and has been used in studies on animals ranging from Baetis to humans.

N

O

osmoregulation - Osmoregulation involves active update of ions through the body wall and excretion of waste products. This is the active regulation of osmotic pressure in a mayfly or other aquatic insect. Osmoregulation is nessecary because cellular processes are finely adapted to a certain amount of solutes in the hemolymph.

ovoviviparity - Eggs containing mature embryos that hatch immediately after the female oviposits. Locally, Callibaetis females smack the pond surface with their abdomen, which splits and deposits tiny nymphs in the water.

P

paraphyletic - A group of animals where most of the animals are related, but excluding one of two See monophyletic. groups.

polyphyletic - A group of animals containing many taxa that are not closely related.

Q

R

S

subimago - The first adult stage of a mayfly, also called a dun in fishing circles. Subimagos have wings but are not fully mature. Depending on the species, after a few hours to a few days, the subimago molts into a sexually mature imago. Mayflies are unusual in the insect world because they have two stages as an apparent adult.

synonym - Used in the nomenclature, or naming of animals and plants, to indicate an older scientific name that is no longer used. Usually these name changes take a few years to spread through the scientific and fishing community. Synonyms in older literature can be confusing for widespread and common isects. On this website, I comment when an older name was widely used. Check the Integrated Taxonomic Information System website if you are curious about a mayflies name.

T

TSN - Taxonomic Serial Number, a unique number for each species, genera, and all taxnomic levels created by Integrated Taxonomic Information System for use in databases.

U

V

ventral - The front side of an animal. For example, the ventral side contains the stomach and chest side of an animal, however is used to describe that direction for all relevent body parts. See dorsal.

W

X

Y

Z

Brown, WS 2005 Mayfly Glossary
www.gunnisoninsects.org