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Odonata (Dragon- and Damselflies) of Michigan - Identification
The insect order Odonata is an old insect order having evolved in the Pennsylvannian and dominated in the Permian. Today, there are more than 5,000 species grouped into two extant suborders: Zygoptera (damselflies) and Anisoptera (dragonflies). Anisozygoptera (family Epiophlebiidae), previously considered a third suborder and intermediate to the previous two, is now considered to share an ancestor with Anisoptera and the three Asian species are now considered as primitive Anisoptera (Tennessen 2003, Dumont et al. 2010; however, see Dijkstra et al. 2013 for a competing view).
Distinguishing between the two suborders of Michigan is rather easy. Both nymphs and adults of all Odonata are carnivores. Nymphs of all our species are aquatic (some semi-terrestrial species exist in other parts of the world), respiring by means of gills (internal with Anisopera, external with Zygoptera, the later that may also respire cutaneously). The modified labium, used by nymphs to capture food, characterizes the immature stage of this order from from all other insects. It is held underneath the head, and, when prey is detected, thrusted out in a lightning-like strike. Prey is then seized with palpal lobes at the end of the labium, brought to the mouth and finally macerated with the larva's mandibles. Adults are large, agile fliers. The wings of anisopterans, which are dissimilarly shaped, are held horizontally (sometimes flexed below the body line) when at rest, whereas those of zygopterans, which are similarly shaped, are held together above the body (sometimes partly spread apart in Lestes and Chromagrion) (Westfall and Tennessen 1996). The eyes of zygopterans are generally situated further apart than with most anisopterans. Wing venation is commonly used to distinguish higher level taxa.
Adults
(adapted from Needham et al. 2014, Westfall and May 1996)
1a |
a. Front
and hind wings similar in shape and size, each with a quadrangle instead
of a triangle and subtriangle |
Zygoptera,
2 |
b. Eyes separated
by more than their own width |
c. Males with 2
inferior appendages (paracprocts) |
d. Females with
a fully developed ovipositor bearing styli |
e. When perched,
wings held together above abdomen or only partly spread |
1b |
a. Front and hind
wings dissimilar in shape and size, the hind wing considerably wider
at base than the front wing, each having a triangle and subtriangle |
Anisoptera,
4 |
b. Eyes meeting
middorsally or not separated by a space grater than their own width |
c. Males with a
single inferior appendage (epiproct), which my be bifid |
d. Females with
or without an ovipositor |
e. When perched,
wings usually held horizontally |
|
2a |
a. Antenodal cross
veins numerous |
Calopterygidae |
b. Postnodal crossveins
not in line with the veins below them |
c. Anal vein at
its base separate from posterior border of wing |
d. Quadrangle with
several crossveins |
2b |
a. Only 2 antenodal
crossveins present |
3 |
b. Postnodal crossveins
in line with the veins below them |
c. Anal vein joined
with wing margin for a distance from the wing base |
d. Quadrangle never
with crossveins |
|
3a(2b) |
Veins M3 and Rs
arising nearer the arculus than the nodus |
Lestidae |
3b |
Veins M3 and Rs
arising nearer the nodus than the arculus |
Coenagrionidae |
also: Anal vein
and Cu2 present, quadrangle distinctly trapezoidal |
|
4a(1b) |
a. Triangles of
forewings < 2x as far from arculus as those of hind wings |
5 |
b. Triangles of
both wings similar in shape, generally elongated in long axis of wings |
c. The 2 antenodal
crossveins thickened, most of the other antenodals of the 1st series
not aligned with those of the 2nd series |
4b |
a. Triangles of
forewings at least > 2x as far from arculus as those of hind wings |
8 |
b. Triangles of
forewings generally elongated transversely, those of hind wings elongated
longitudinally |
c. No thickened
antenodal crossveins, those of the 1st series aligned with those of
the 2nd series |
|
5a(4a) |
a. Brace crossvein
absent |
Cordulegastridae |
b. Eyes barely contiguous
dorsally or very slightly separated, by distance much less than distance
between lateral ocelli |
c. In ventral view,
prementum with large anteromedian cleft |
d. Ovipositor of
female with gonapophyses extending well beyond posterior margin of
Ab10 and without styli |
5b |
a. Brace crossvein
present near proximal end of pterostigma |
6 |
b. Eyes either in
contact for some distance dorsally (Aeshnidae), or widely separated
(Gomphidae, Petaluridae), distance about equal to distnace between
lateral ocelli |
c. prementum variable |
d. ovipositor variable |
|
6a(5b) |
a. Eyes in contact
for some distance dorsally, forming a distinct eye seam |
Aeshnidae |
b. In ventral view,
anterior margin of prementum with median cleft small, sometimes nearly
obsolete |
c. Male epiproct
usually triangular (except Gomphaeschna and Anax) |
d. Female ovipositor
with well-developed, bladelike gonapophyses, the outer pair each bearing
a stylus |
6b |
a. Eyes widely separated,
distance about equal to distance between lateral ocelli |
7 |
b. Male epiproct
not triangular |
c. Prementum and
ovipositor variable |
|
7a(6b) |
a. In ventral view,
prementum with large anteromedian cleft |
Petaluridae, Tachopteryx
thoreyi (Hagen) |
b. Pterostigmata
each at least 0.25x the distance from the nodus to the end of vein
R1, narrow, slightly concace along posterior side |
c. Ovipositor with
well-developed, blade-like gonapophyses, the outer pair each bearing
a stylus |
Note: very rare
in Michigan, currently known from around areas of groundwater seeps
at only two localities in SW Michigan |
7b |
a. In ventral view,
prementum entire |
Gomphidae |
b. Pterostigmata
each much less than 0.25x the distance from the nodus to the end of
vein R1, slightly widened at midlength, and thus not concave posteriorly |
c. Ovipositor reduced
to small subgenital plate |
|
8a(4b) |
a. Triangle of each
hindwing about 0.5x as far from arculus as that of each forewing |
Macromiidae |
b. Anal loop short
and wide, without midrib |
c. Abdomen without
lateral carinae |
8b |
a. Triangle of each
hindwing much less than 0.5x as far from arculus as that of each forewing |
9 |
b. Anal loop elongate,
divided lengthwise by distinct midrib into 2 rows of cells (absent
in Nannothemis) |
c. Lateral carinae
on Ab3, 4, or 5 to Ab8 or 9 |
|
9a(8b) |
a. Anal loop slightly
expanded distally but without distinct "toe" |
Corduliidae |
b. In lateral view,
posterolateral margin of each eye distinctly sinuate |
c. Anal border of
male hind wing with an anal triangle and the anal margin angulate |
d. Males: anal border
of each hindwing of angulate, auricles present on Ab2, and keels present
on metatibiae |
9b |
a. Anal loop usually
markedly expanded distally, with distinct "toe" (absent in Nannothemis) |
Libellulidae |
b. In lateral view,
posteriorlateral margin of each eye hardly sinuate |
c. Anal border of
each hindwing of both sexes rounded, and males without an anal triangle |
d. Males: without
auricles on Ab2, and without metatibial keels |
Nymphs
(adapted
from Westfall and Needham 1996, Needham et al. 2014, Tennessen 2019, Walker & Corbet 1975)
1a |
a. Body
slender, head wider than thorax and abdomen |
Zygoptera,
2 |
b. Abdomen terminating
in three caudal lamellae |
1b |
a. Body stout, head
usually narrower than thorax and abdomen |
Anisoptera,
4 |
b. Abdomen terminating
in 5 short, stiff, pointed appendages |
|
2a |
a. First antennal
segment elongate, greater than segments 2-5 combined |
Calopterygidae |
b. Prementum with
deep median cleft |
2b |
a. First antennal
segment not so elongate, less than segments 2-5 combined |
3 |
b. Prementum with
at most a tiny median cleft |
|
3a |
Basal half of labium
greatly narrowed and elongate, folded labium extends back to mesocoxae
or beyond |
Lestidae |
3b |
Basal half of labium
not greatly narrowed, folded labium extends back only to procoxae |
Coenagrionidae |
|
4a |
a. Mentum flat or nearly
so, without dorsal premental setae |
5 |
b. Labial palps nearly flat, not greatly expanded distally, not covering labrum, usually lacking setae |
4b |
a. Prementum transversely concave upward, with prominent premental setae |
7 |
b. Palpal
lobes forming spoon-shaped structure covering labrum, greatly expanded distally with prominent setae |
|
5a |
a. Antennae 4-segmented,
third segment often enlarged |
Gomphidae |
b. Pro- and metatarsi
2-segmented |
c. Ligula without
a median cleft |
5b |
a. Antennae 6- and
7-segmented |
6 |
b. Pro- and metatarsi
tarsi 3-segmented |
c. Ligula with a
median cleft |
|
6a |
a. Antennae segments
short, thick, and hairy |
Petaluridae, Tachopteryx
thoreyi (Hagen) |
b. Prementum with
sides sub-parallel in distal three-fifths, abruptly narrowed near base |
c. A pair of lateral-dorsal
abdominal hair tuft present |
Note: rare, in
groundwater seeps, known from only 2 localities in SW LP Michigan |
6b |
a. Antennal segments
slender and bristle-like |
Aeshnidae |
b. Prementum widest
in distal half, then much narrower in basal half or more |
c. Abdomen without
lateral-dorsal abdominal hair tufts |
|
7a |
a. Distal edge of
lateral lobe with large, irregular teeth without associated setae |
Cordulegastridae |
b. Ligula with a
median tooth-like cleft |
7b |
a. Distal edge of
lateral lobe entire, or with even-sized dentations, with associated
setae |
8 |
b. Ligula not as
above |
|
8a |
a. Head with thick,
erect frontal horn postitioned between antennae |
Macromiidae |
b. Metafemur very
long, reaching at least to apex of Ab8 |
c. Metasternum with
broad, transverse median tubercle |
d. Mesinfraepimeron with a triangular, anteriorly-directed lobe on each side of postmentum |
8b |
a. Head without
frontal horn positioned between antennae |
9 |
b. Metafemur not reaching
apex of Ab8 |
c. Metasternum without
a transverse median tubercle |
d. Mesinfraepimeron without a triangular, anteriorly-directed lobe on each side of postmentum |
|
9a |
a. Prementum almost always with a distinct longitudinal medial groove at the base on the ventral surface |
Corduliidae |
b. Crenations on the distal margin of the labial palps mostly 1/4-1/2 as high as broad, separated by relatively deep notches |
c. Cerci usually at least 0.6x the length of the paraprocts |
d. Lateral spines of Ab8 absent, or distinctly shorter than the middorsal length of Ab9 |
9b |
a. Prementum almost always lacking a distinct longitudinal medial groove as above |
Libellulidae |
b. Crenations on the distal margin of the labial palps usually nearly smooth, or mostly 0.10-0.17 as high as broad, separated by shallow notches |
c. Cerci most often <0.6x the length of the paraprocts |
d. IF neither of the above (Pantala), then lateral spines of Ab8 at least as long as the middorsal length of Ab9 |
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References
Dijkstra KDB, Bechly G, Bybee SM, Dow RA, Dumont HJ, Fleck G, Garrison RW, Hämäläinen M, Kalkman VJ, Karube H, May ML, Orr AG, Paulson DR, Rehn AC, Theischinger G, Trueman JWH, van Tol J, von Ellenrieder N, Ware J. 2013The classification and diversity of dragonflies and damselflies (Odonata), in Zhang, Z.-Q. (Ed.) Animal Biodiversity: An Outline of Higher-level Classification and Survey of Taxonomic Richness (Addenda 2013). Zootaxa 3703:1–82.)
Dumont HJ, Vierstraete A, Vanfleteren JR. 2010. A molecular phylogeny of the Odonata (Insecta). Systematic Entomology 25:6-18.
Needham JG, Westfall MJ, May ML. 2014. Dragonflies of North America, Third Edition. Scientific Publishers: Gainesville, Florida. xvi + 657 pp.
Tennessen KJ. 2003. Odonata (Dragonflies, Damselflies), pp. 814-823 in Encyclopedia of Insects. Resh VH, Cardé RT (eds.). Academic Press, San Diego, California, USA.
Tennessen KJ. 2019. Dragonfly nymphs of North America: An Identification Guide. Springer International Publishing, Cham, Switzerland: xiv + 620 p.
Walker EM, Corbet PS. 1975. The Odonata of Canada and Alaska, Vol. 3. University of Toronto Press: Toronto. xvi + 308 pp.
Westfall MJ, Tennessen KJ. 1996. Odonata, pp. 164-211 in An Introduction to the Aquatic Insects of North America, 3rd Ed. Merritt RW, Cummins KW (eds.). Kendell/ Hunt Publishing Company: Dubuque, Iowa.
Last updated:
April 24, 2020
(EB)
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