Neurocordulia Selys, 1871 (Corduliidae) - Shadowdragons


Notes - Michigan Species List - Key - References
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Page last updated: 11 March 1998

Notes on the Michigan Species of Neurocordulia

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

Mature larvae are medium-sized, compact yellow-brown odonates with long, distinctively dark banded legs and dark, stubby mid-dorsal abdominal spines on segments 2-9. Larvae are found in coarser substrates of well-oxygenated portions of wind-swept lakes as well as streams and rivers, where larvae cling to the undersides of boulders, loosened material and even the large cracks of logs and other woody debris (Walker and Corbet 1975; P. Brunnell, pers. comm.). Adult emergence usually occurs from mid-June through early-July. Flight appears to be mainly crepuscular, which helps account for the difficulty in collecting adult specimens.

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

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Michigan Species List

*Neurocordulia obsoleta (Say, 1839) - Umber Shadowdragon
Neurocordulia yamaskanensis (Provancher, 1875) - Stygian Shadowdragon

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

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Key to the Mature Larvae of Neurocordulia
(Adapted from
Needham and Westfall 1955 and P. Brunelle (pers. comm.))

1a. Lateral spine of abdominal segment 9 does not surpass tips of the epiproct and paraprocts (picture); mid-dorsal abdominal spines pointing rearward (picture) - N. yamaskanensis

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


References

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

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

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

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

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