Neurocordulia Selys, 1871 (Corduliidae) -Shadowdragons


Notes - MichiganSpecies List - Key -References
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Page last updated: 11 March1998

Notes on theMichigan Species of Neurocordulia

This Nearctic genus is distributed primarily inthe southeastern USA, with one species having been reliably recordedin Michigan. Few records exist from our state (fig. 1, below); I (EB)have seen four specimens: two exuvia of N. yamaskanensis collectedby Ed Kormondy from the UM Biological Station at Douglas Lake in 1953(Cheboygan County), an exuvia of N.yamaskanensis collected by M. O'Brienfrom Ives Lake in 1997 (Marquette County), and an early instar foundnearby Ives Lake (Pine River) which appears to be N. obsoleta collected byStan Yanovich. An old record of N.obsoleta listed in Needham and Westfall(1955) is erroneous, as Byer's originallisting from 1927 had been corrected by E. B. Williamson and changedto N. yameskanensis by 1937. N.obsoleta is not yet officially part ofour state's fauna, but its presence in Ohio and Wisconsin makes itlikely that it will be encountered in our state and is included inthe key below.

Mature larvae are medium-sized, compactyellow-brown odonates with long, distinctively dark banded legs anddark, stubby mid-dorsal abdominal spines on segments 2-9. Larvae arefound in coarser substrates of well-oxygenated portions of wind-sweptlakes as well as streams and rivers, where larvae cling to theundersides of boulders, loosened material and even the large cracksof logs and other woody debris (Walker and Corbet1975; P. Brunnell, pers. comm.). Adultemergence usually occurs from mid-June through early-July. Flightappears to be mainly crepuscular, which helps account for thedifficulty in collecting adult specimens.

Other links with information on the biology orecology of larval Neurocordulia:
Briefhabitat notes from Ottawa (Ontario, Canada)>>http://www.ncf.carleton.ca/~bf250/odonata.html

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Michigan SpeciesList

*Neurocorduliaobsoleta (Say, 1839) - Umber Shadowdragon
Neurocorduliayamaskanensis (Provancher,1875) - Stygian Shadowdragon

* Not yet recorded in Michigan, but maybe encountered in the state
fig. 1: Click on map to enlarge

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Key to the Mature Larvaeof Neurocordulia
(Adapted from
Needham and Westfall1955 and P. Brunelle (pers.comm.))

1a. Lateralspine of abdominal segment 9 does not surpass tips of the epiproctand paraprocts (picture); mid-dorsal abdominal spines pointingrearward (picture) - N.yamaskanensis

1b.Lateral spine of abdominal segment 9 extending past the of tips ofepiproct and paraprocts (picture); mid-dorsal abdominal spinespointing upright (picture) - N.obsoleta


References

Needham, J.G., and M. J. Westfall, Jr. 1955. A Manual of the Dragonflies ofNorth America (Anisoptera). University of California Press: Berkeley,California. xii + 615 pp.

Say, T. 1839.Descriptions of new North American neuropterous insects andobservations on some already described by (the late) Th. Say.Journal of the Academy of NaturalScience of Philadelphia 8:9-46.

Selys-Longchamps, M.E. de. 1871. Synopsis des Cordulines. Bulletin de l'Académie royale des Sciences deBelgique (2)31:238-316.

Walker, E. M., and J.S. Corbet. 1975. The Odonata of Canada and Alaska, Vol. 3. Universityof Toronto Press: Toronto, Ontario. xvi + 308.

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