Lab Notes for the Ephemeroptera - "Mayflies"

Notes on taxonomy
Some recent synonymies for taxa found in Michigan
Notes on sexual dimorphism and other features of adult mayflies
List of Ephemeroptera taxa presented
Table of habitat preferences
Emergence sequence table for some Michigan Ephemeroptera
References and recent additional taxonomic works
Doc Leonard's notes on Ephemeroptera (separate page)

Readings and Keys

Readings in required texts:

Edmunds and Waltz 1996, pp. 126-130 in Merritt and Cummins (larvae and adults - genera)
Hilsenhoff 1995, pp. 4--6 (larvae)

Notes on Taxonomy

We follow McCafferty's (1991a) higher-level taxonomy in terms of sub-ordinal classification, which is now regularly updated on the Mayfly Central internet site. (See that site for a complete classification for all North American genera). The list below includes those genera found (or may be found) in Michigan. 

Order Ephemeroptera
          Suborder Carapacea
                         Family Baetiscidae
                              Genus Baetisca Walsh
          Suborder Furcatergalia
               Infraorder Lanceolata (leptophlebiids)
                         Family Leptophlebiidae
                              Genus Choroterpes Eaton
                              Genus Leptophlebia Westwood
                              Genus Paraleptophlebia Lestage
               Infraorder Palpotarsa (the primitive burrowing mayflies)
                         Family Behningiidae
                              Genus Dolania Edmunds & Traver
               Infraorder Scapphodonta (the burrowing mayflies)
                         Family Potamanthidae
                              Genus Anthopotamus McCafferty & Bae
                         Family Polymitarcyidae
                         (=Euthyplociidae + Polymitarcyidae)
                              Genus Ephoron Williamson
                         Family Ephemeridae
                         (=Ephemeridae + Palingeniidae)
                              Genus Ephemera Linnaeus
                              Genus Hexagenia Walsh
                              Genus Litobrancha McCafferty
                              Genus Pentagenia Walsh
               Infraorder Pannota (the pannote mayflies)
                    Superfamily Caenoidea
                         Family Neoephemeridae
                              Genus Neoephemera McDunnough
                         Family Caenidae
                              Genus Brachycercus Curtis
                              Genus Caenis Stephens
                    Superfamily Ephemerelloidea
                         Family Ephemerellidae
                              Genus Attenella Edmunds
                              Genus Drunella Needham
                              Genus Ephemerella Walsh
                              Genus Eurylophella Tiensuu
                              Genus Serratella Edmunds
                              Genus Timpanoga Needham
                         Family Leptohyphidae
                         (=Tricorythidae, subfamily Leptohyphinae)
                              Genus Leptohyphes Eaton
                              Genus Tricorythodes Ulmer
          Suborder Pisciforma
                         Family Acanthametropodidae
                         (=Acanthametropodidae + Analetrididae)
                         (=Siphlonuridae, subfamily Acanthametropodinae)
                              Genus Acanthametropus Tshernova
                         Family Ameletidae
                         (=Siphlonuridae, subfamily Siphlonurinae in part)
                              Genus Ameletus Eaton
                         Family Ametropodidae
                              Genus Ametropus Albarda
                         Family Baetidae
                              Genus Acentrella Bengtsson
                              Genus Acerpenna Waltz & McCafferty
                              Genus Baetis Leach
                              Genus Callibaetis Eaton
                              Genus Centroptilum Eaton
                              Genus Cloeon Leach
                              Genus Diphetor Waltz & McCafferty
                              Genus Heterocloeon McDunnough
                              Genus Paracloeodes Day
                              Genus Plauditus Lugo-Ortiz & McCafferty
                              Genus Procloeon Bengtsson
                              Genus Pseudocentroptiloides Jacob
                              Genus Pseudocloeon Klapálek
                         Family Metretopodidae
                              Genus Metretopus Eaton
                              Genus Siphloplecton Clemens
                         Family Siphlonuridae
                         (=Siphlonuridae, subfamily Siphlonurinae in part)
                              Genus Parameletus Bengtsson
                              Genus Siphlonurus Eaton
          Suborder Setisura
                         Family Isonychiidae
                         (=Oligoneuriidae, subfamily Isonychiinae)
                         (=Siphlonuridae, subfamily Isonychiinae)
                              Genus Isonychia Eaton
                         Family Oligoneuriidae
                              Genus Homoeoneuria Eaton
                         Family Pseudironidae
                         (=Heptageniidae, subfamily Pseudironinae)
                         (=Siphlonuridae, subfamily Pseudironinae)
                              Genus Pseudiron McDunnough
                         Family Arthropleidae
                         (=Heptageniidae, subfamily Arthropleinae)
                              Genus Arthroplea Bengtsson
                         Family Heptageniidae
                         (=Heptageniidae, subfamily Heptageniinae)
                              Genus Anepeorus McDunnough
                              Genus Epeorus Eaton
                              Genus Heptagenia Walsh
                              Genus Leucrocuta Flowers
                              Genus Nixe Flowers
                              Genus Raptoheptagenia Whiting & Lehmkuhl
                              Genus Rhithrogena Eaton
                              Genus Stenacron Jensen
                              Genus Stenonema Traver

Some recent synonymies for taxa found in Michigan (current = old)

Tricorythodes (Leptohyphidae) = Tricorythodes (Tricorythidae)
Litobrancha = Hexagenia
(Ephemerella + Drunella + Serratella + Eurylophella + Timpanoga + Attenella) = Ephemerella (sensu lat.)
Isonychia (Isonychiidae ) = Isonychia (Oligoneuriidae) = Isonychia (Siphlonuridae)
Ametropodidae + Metretopodidae = Ametropodidae (prt.)
(Stenonema + Stenacron) = Stenonema
Anepeorus = Spinadis
Nixe = Heptagenia (part)
Leucrocuta = Heptagenia (part)
Anthopotamus = Potamanthus
Acentrella = Pseudocloeon
Centroptilum = Cloeon (part)
Procloeon = Cloeon, Centroptilum (parts)
Acerpenna = Baetis (part)
Diphetor = Baetis (part)
Pseudocloeon = Labiobaetis, Baetis (part)
Plauditus = Baetis (part)

Notes on Sexual dimorphism and other features of adult mayflies

In most Ephemeroptera, the eyes of the male are large and in proximity on the vertex, while those of the female are small and separate. In many species of Caenidae and Leptohyphidae, however, the eyes of both sexes are small. In males of Baetidae and some Leptophlebiidae, the upper facets of the eyes are raised on a stalk (= turbinate or semiturbinate).

Generally, the legs of Th1 are much longer than legs of Th2-3 in males, while in females, legs of Th1-3 are subequal. In Polymitarcyidae, however, the legs on Th2-3 in males and Th1-3 in females are vestigial. All legs of both sexes are vestigial in North American Behningiidae (genus Dolania).

In the families Leptohyphidae, Caenidae, Baetidae and in some Neotropical Leptophlebiidae, the HW (on Th3) are greatly reduced or completely absent. In some Baetidae, the HW are small and without a costal projection in males, and minute in females. In other baetids, HW are absent in both sexes. In at least a few populations, males have HW but females do not.
The abdomen externally consists of Ab1-10T and Ab1-10S. The posterior portion of Ab7S of males is called the subgenital plate and is variable in form. Paired appendages called the forceps (=claspers) arise from the posterior margin of the subgenital plate (fig. 11.96, p. 144 in Edmunds and Waltz (1996)). In some genera, the forceps are 1-segmented (e.g., Caenis, Tortopus). More generally, the forceps consist of 2, 3, or 4 segments. Dorsal to the subgenital plate are paired penes, which often are fused mesally. In most taxa, the penes are sclerotized, but in the Baetidae they are membranous and extrudable. The genitalia of male mayflies can be seen through the pellicle of the subimago and the mature nymph, although the structures are less developed than in the imago. The posterior portion of Ab9S of females is termed the subanal plate. The posterior margin of the subanal plate, although generally rounded and w/o prominent processes, is variable in form and can have taxonomic value. In a few genera, the female has a rudimentary ovipositor. Unassociated adult females can not in some cases (e.g., some Ephemerellidae and Leptohyphidae) be easily or reliably determined to genus.

Classification of wing venation will differ between authors. Early Ephemeropterists (e.g., Needham, Traver and Hsu 1935, Burks 1953) followed the Comstock classification of venation, and considered R4+5 to be a branch of R5. Later workers (Edmunds, Jensen and Berner 1976) used the system of Tillyard, which interpreted this vein as a branch of M. Thus, R4+5 of Comstock = MA of Tillyard (R4 = MA1 and R5 =MA2). Page 143 in Edmunds and Waltz (1996) gives Tillyard's (1932) system applied to Ephemeroptera. In the Tillyard system, MA (MA1 and MA2) is convex and MP (MP1 and MP2) is concave. The branched vein MA(+) is the most obvious landmark for identifying venation of the mayfly FW.

Venation is reduced in the HW and often is difficult to interpret. Reduction in the number of wing veins and wing size (especially HW) is frequently associated with reduction in body size, and apparently has evolved independently in several lineages (e.g., Caenidae, Baetidae, Leptohyphidae) (Edmunds 1972).

In North America, Heptageniidae and Baetidae A. have 2 caudal filaments, while Leptophlebiidae and Ephemerellidae A. have 3 caudal filaments. When the median terminal filament is vestigial, it often is represented by a tapered rudiment of 1 or few segments. When fully-developed caudal filaments have been broken, the basal remnants are of normal diameter.
Subimagines have dull, translucent wings, dull body surfaces, and setae on the wing margins. Imagines of some smaller species, however, retain setae on the wing margins. The caudal filaments are usually covered w/fine setae in subimagines and are glabrous in imagines. Caudal filaments generally are much longer in the imago than in the subimago. In some genera, the molt to the imago can be incomplete, with the wings retaining the subimaginal pellicle, and the caudal filaments may not be shed. In a few taxa, there is no imaginal stage in the females.

List of Ephemeroptera Taxa Presented

You must be able to identify in a lab exam the following taxa, larvae to genus, adults to family.

Family

Genus

Vial #

Stage

Ameletidae

Ameletus

E-01

L

Baetidae

Baetis

E-02

L

Baetidae

Callibaetis

E-03

L

Baetidae

Acentrella

E-04

L

Baetiscidae

Baetisca

E-05

L

Caenidae

E-06

A

Caenidae

Caenis

E-07

L

Ephemerellidae

E-08

A

Ephemerellidae

Drunella

E-09

L

Ephemerellidae

Ephemerella

 E-10

L

Ephemerellidae

Serratella

 E-11

L

Ephemeridae

E-12

A

Ephemeridae

Ephemera

E-13

L

Ephemeridae

Ephemera

E-14

A

Ephemeridae

Hexagenia

E-15

L

Ephemeridae

Litobrancha

E-16

L

Heptageniidae

E-17

A

Heptageniidae

Epeorus

E-18

L

Heptageniidae

Heptagenia (check for Nixe)

E-19

L

Heptageniidae

Rhithrogena

E-20

L

Heptageniidae

Stenacron

E-21

L

Heptageniidae

Stenonema

E-22

L

Heptageniidae

Stenonema

E-23

A

Isonychiidae

Isonychia

E-24

L

Leptohyphidae

Tricorythodes

E-25

L

Leptophlebiidae

Leptophlebia

E-26

L

Leptophlebiidae

Paraleptophlebia

E-27

L

Leptophlebiidae

cf. Paraleptophlebia

E-28

A

Metretopodidae

Siphloplecton

E-29

L

Polymitarcyidae

Ephoron

E-30

L

Potamanthidae

Anthopotamus = Potomanthus

E-31

L


Table of Habitat Preferences

 

SLOW CURRENT

FAST CURRENT
Taxa

Sand  and gravel

 Mud Leaf drift and similar detritus submerged plant beds and logs under stones Silt and finer detritus Open water Gravel and rubble Leaf drift and similar detritus submerged plant beds and logs undersides of stones Open water
Burrowing Nymphs                        
Ephemera simulans                        
Hexagenia atrocaudata   beaver ponds                    
Hexagenia limbata                        
Hexagenia rigida   warm streams                    
Litobrancha recurvata   cold streams                    
Clinging Nymphs                        
Acentrella spp.                        
Acerpenna pygmaea                        
Baetis brunneicolor       quiet water only                
Baetis flavistriga                        
Baetis intercalaris               more frequent         
Baetis tricaudatus                        
Baetisca laurentina           cold streams            
Baetisca obesa           warm streams            
Brachycercus lacustris           warm streams            
Caenis amica                        
Caenis latipennis           also spring-holes            
Callibaetis ferrugineus       quiet water only                
Drunella cornuta               Precambrian bedrock        
Drunella lata                        
Drunella walkeri                        
Epeorus vitreus                        
Ephemerella dorothea                        
Ephemerella excrucians                        
Ephemerella invaria                        
Ephemerella needhami                        
Ephemerella rotunda                        
Ephemerella subvaria                        
Eurylophella lutulenta                        
Eurylophella temporalis                        
Heptagenia pulla                        
Leptophlebia cupida                        
Leptophlebia nebulosa                        
Leucrocuta hebe                 more frequent      
Paraleptophlebia adoptiva                        
Paraleptophlebia debilis                        
Paraleptophlebia mollis                        
Paraleptophlebia praepedita                        
Rhithrogena impersonata                        
Rhithrogena impersonata                        
Rhithrogena jejuna                        
Rhithrogena pellucida                        
Serratella deficiens                        
Serratella deficiens                        
Stenacron interpunctatum                        
Stenonema femoratum                        
Stenonema ithaca                        
Stenonema luteum                        
Stenonema mediopunctatum                        
Stenonema pulchellum       prefers logs           prefers logs    
Stenonema vicarium                        
Timpanoga simplex                        
Tricorythodes spp.           cold streams            
Free-swimming nymphs                        
Isonychia bicolor                        
Metretopus borealis             Pre-Cambrian bedrock streams          
Procloeon album             warm streams          
Siphlonurus alternatus                        
Siphlonurus quebecensis                        
Siphlonurus rapidus                        
Siphloplecton basale                        

Table of Emergence Sequence for Ephemeroptera

Mayflies found in a single gravel riffle in the Pere Marquette River with dates of emergence. (Data from
Leonard and Leonard 1962, p. 8; names have been taxonomically updated).
___________________________________________________________________________________
Taxa                                             April        May        June         July           Aug         Sept        
___________________________________________________________________________________
Baetis tricaudatus                             xxxxxx
Ephemerella subvaria                                    xxx
Paraleptophlebia praepedita                                xxxxx
Ephemerella invaria                                              xxxxxxx
Baetis cinctutus                                                        xxxxxxxxxxxxxxxxxxxxx
Leptophlebia cupida                                                   xxx
Siphlonurus quebecensis                                          xxxxxxx
Pseudocloeon punctiventris                                           xxxxxxxxxxxxxxxxxx
Epeorus vitreus                                                            xxxxxxxxxx
Stenonema vicarium                                                          xxxxxx
Ephemerella rotunda                                                             xxx
Paraleptophlebia mollis                                                           xxxxxxxxxxx
Baetisca laurentia                                                                    x
Ephemerella dorothea                                                              xx
Siphlonurus rapidus                                                                  x
Ephemerella needhami                                                                xxxxxx
Procloeon album                                                                            xxx
Drunella lata                                                                           xxxxxxxxxx
Stenonema modestum                                                                 xxxxxxxxxxxx
Siphlonurus alternatus                                                                     xxxxxxx
Drunella walkeri                                                                         xxxxxxx
Hexagenia limbata                                                                          xxxxxxxx
Leucrocuta hebe                                                                             xxxxxxxxxxxxxxxxxxx
Rhithrogena impersonata                                                                     x 
Timpanoga simplex                                                                              xxxxx      xx
Brachycercus lacustris                                                                          xxxxx
Serratella deficiens                                                                              xxxxx
Tricorythodes stygiatus                                                                               xxxxxxxxxxxxx
Isonychia bicolor                                                                                               xxxxxxxxx
___________________________________________________________________________________

References and Recent Additional Taxonomic Works

Allen, R.K. 1980. Geographic distribution and reclassification of the subfamily Ephemerellidae (Ephemeroptera:Ephemerellidae). pp.71-79 in J. F. Flannagan & K. E. Marshall (eds.) Advances in Ephemeroptera biology. Plenum, N.Y. 552 pp.
Bae, Y. J., and W. P. McCafferty. 1991. Phylogenetic systematics of the Potamanthidae (Ephemeroptera). Transactions of the American Entomological Society 117:1-143.
Berner, L. 1950. The mayflies of Florida. University of Florida Studies Biological Science Service A 4:1-267.
_____________. 1975. The mayfly family Leptophlebiidae in the southeastern United States. Florida Entomologist 58:137-156.
Berner, L., and M. L. Pescador. 1980. The mayfly family Baetiscidae (Ephemeroptera). part I., pp. 511-524. In J. F. Flannagan and K. E. Marshall (eds.). Advances in Ephemeroptera biology. Plenum, New York. 552 pp.
Berner, L., and M. L. Pescador. 1988. The mayflies of Florida (rev. ed.). University Presses of Florida, Gainesville. 415 pp.
Burian, S. K., M. A Novak, R. W. Bode, and L. Abele. 1997. New record of Brachycercus maculates Berner (Ephemeroptera: Caenidae) from New York and a key to larvae of Northeastern species. The Great Lakes Entomologist 30(3):85-88.
Burks, D. D. 1953. The Mayflies of Illinois. Bulletin of the Illinois Natural History Survey 26:1-216. There is also a 1975 reprint with a 1974 new preface from G. F. Edmunds, Jr.
Edmunds, G. F. Jr., 1972. Biogeography and evolution of the Ephemeroptera. Annual Review of Entomology 17:21-43.
Edmunds, G. F, and R. D. Waltz. 1996. Ephemeroptera, pp. 126-163. In An introduction to the aquatic insects of North America, 3rd Edition. R. W. Merritt and K. W. Cummins (eds.). Kendell/Hunt Publishers, Dubuque, Iowa. 862 pp.
Edmunds, G. F, and W. P. McCafferty. 1996. New field observations on burrowing in Ephemeroptera from around the world. Entomological News 107:68-76.
Edmunds, G. F. Jr., S. L. Jensen and L. Berner, 1976. The mayflies of North and Central America. University of Minnesota Press, Minneapolis, 330 pp.
Flowers, R. W., and W. L. Hilsenhoff. 1975. Heptageniidae (Ephemeroptera) of Wisconsin. The Great Lakes Entomologist 8:201-218.
Funk, D. H., and B. W. Sweeney. 1994. The larvae of Eastern North American Eyrylophella Tiensuu (Ephemeroptera: Ephemerellidae). Transactions of the American Entomological Society 120(3):209-286.
Hilsenhoff, W. L. 1995. Aquatic insects of Wisconsin, 3rd Ed. Natural History Museums Council, University of Wisconsin-Madison. Madison, Wisconsin. 79 pp.
Koss, R. W. 1968. Morphology and taxonomic use of Ephemeropteran eggs. Annals of the Entomological Society of America 61:696-721.
Leonard, J. W. & F. A. Leonard. 1962. The mayflies of Michigan trout streams. Cranbrook Institute of Science Bulletin No. 43.
Lugo-Ortiz, C. R., and W. P. McCafferty. 1998. A new North American genus of Baetidae (Ephemeroptera) and key to Baetis complex genera. Entomological News 109(5):345-353.
_____________.1999. Definition and reorganization of the genus Pseudocloeon (Ephemeroptera: Baetidae) with new species descriptions and combinations. Transactions of the American Entomological Society 125(1-2)1-37.
_____________.1999. Global biodiversity of the mayfly family Baetidae (Ephemeroptera): a generic perspective. Trends in Entomology 2:45-54.
McCafferty, W. P. 1991a. Toward a phylogenetic classification of the Ephemeroptera (Insecta): A commentary on systematics. Annals of the Entomological Society of America 84:343-360.
_____________. 1991b. Comparison of Old and New World Acanthametropus (Ephemeroptera: Acanthametropodidae) and other psammophilous mayflies. Entomological News 102:205-214.
_____________. 1992. New larval descriptions and comparisons of North American Choroterpes (Ephemeroptera: Leptophlebiidae). The Great Lakes Entomologist 25:71-78.
_____________. 1994. Distributional and classificatory supplement to the burrowing mayflies (Ephemeroptera: Ephemeroidea) of the United States. Entomological News 105:1-13.
_____________. 1996. The Ephemeroptera species of North America and index to their complete nomenclature. Transactions of the American Entomological Society 122(1):1-54.
_____________. 1998. Ephemeroptera and the great America interchange. Journal of the North American Benthological Society 17(1):1-20.
McCafferty, W. P. & G. F. Edmunds Jr. 1979. The higher classification of the Ephemeroptera and its evolutionary basis. Annals of the Entomological Society of America 72:5-12.
McCafferty, W. P. and A. V. Provonsha. 1985. Systematics of Anepeorus (Ephemeroptera: Heptageniidae). The Great Lakes Entomologist 18:1-6.
McCafferty, W. P., and Y. J. Bae. 1990. Anthopotamus, a new genus for North American species previously known as Potamanthus  (Ephemeroptera: Potamanthidae). Entomological News 101:200-202.
McCafferty, W. P., and R. D. Waltz. 1990. Revisionary synopsis of the Baetidae (Ephemeroptera) of North and Middle America. Transactions of the American Entomological Society 116:769-799, Philadelphia.
McCafferty W. P., Y. P. Bae. 1992. Taxonomic status of historically confused species of Potamanthidae and Heptageniidae (Ephemeroptera). Proceedings of the Entomological Society of Washington 94:169-171.
McCafferty, W. P. and T. H. Klubertanz. 1994. Camelobaetidius (Ephemeroptera: Baetidae) in Indiana and Iowa: new species and range extension. Proceedings of the Entomological Society of Washington 96: 37-43.
McCafferty, W. P., and Wang T-Q. 1994. Phylogenetics and the classification of the Timpanoga complex (Ephemeroptera: Ephemerellidae). Journal of the North American Benthological Society 13:569-579.
_____________. 2000. Phylogenetic systematics of the major lineages of pannote mayflies (Ephemeroptera: Pannota). Transacations of the American Entomological Society 126(1):9-101.
McCafferty, W. P. and R. D. Waltz. 1995. Labiobaetis (Ephemeroptera: Baetidae): new status, new North American species, and related new genus. Entomological News 106: 19-28.
Muller-Liebenau, I. 1973. Morphological characters used in revising the European species of Baetis Leach, pp. 182-198. In W. L. Peters and J. G. Peters (eds.). Proceedings of the first international congress on Ephemeroptera. E. J. Brill, London.
Needham, J. G., J. P. Traver and Y. C. Hsu. 1935. The biology of mayflies with a systematic account of North American species. Comstock, Ithaca.
Randolph, R. P., and W. P. McCafferty. 1998. Diversity and distribution of the mayflies (Ephemeroptera) of Illinois, Indiana, Kentucky, Michigan, Ohio, and Wisconsin. Bulletin of the Ohio Biological Survey, New Series 13(1).
Tomka, I., and A. Zurwerra. 1985. Key to the genera of the Heptageniidae (Ephemeroptera) of the Holarctic, Oriental and Ethiopian Region. Entomogische Berichte Luzern 14:113-126.
Waltz, R. D., W. P. McCafferty, and J. H. Kennedy. 1989. Barbaetis, a new genus of eastern Nearctic mayflies (Ephemeroptera: Baetidae). Great Lakes Entomologist 18:161-165.
Zloty, J. 1996. A revision of the Nearctic Ameletus mayflies based on adult male, with descriptions of seven new species (Ephemeroptera: Ameletidae). Canadian Entomologist 128: 293-346.

Page created: 19 January 2001
last edit: 27 January 2003 (EB)