Plants and Animals

Tachopteryx thoreyi Grey petaltail

Key Characteristics

Large, mostly gray dragonfly. Thorax gray with black stripes, and abdomen black with gray blotches. Separated eyes and linear stigman. Eyes dark brown, becoming gray at maturity.

Status and Rank

US Status: No Status/Not Listed
State Status: E - Endangered (legally protected)
Global Rank: G4 - Apparently secure
State Rank: S1 - Critically imperiled


CountyNumber of OccurrencesYear Last Observed
Berrien 1 1919
Cass 1 1989

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Lotic - depositional (margins and moss of spring streams; upper edges of hillside seepages in deciduous forests). Found in forest openings, lowland conifer, lowland hardwood, fens, swamps. Requires woody structure in aquatic habitats.

Natural Community Types

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

Species is sensitive to continued decrease in water quality. Also affected by impoundments, channelization, dredging, siltation, non-point pollution (agricultural), and industrial pollution. Timber harvests may increase sitation and cause a decrease in dissolved oxygen. Also affected by altered hydrologic regimes, riparian modifications and wetland modifications. Forest cover and hydrological patterns should be maintained at intact sites and restored at disturbed locations.

Survey Methods

An exuvia survey consists of searching the banks and protruding rocks of rapid streams for the cast skin of dragonfly larvae. It characteristically perches on the trunks of trees and often on people wearing neutral colored clothing. Males can be seen flying up and down the trunks of trees as they meticulously search for females. They rarely stray far from their forest habitat.

Aerial net, visual survey

Survey Period: From fourth week of May to third week of August

Time of Day: Daytime
Survey Method Comment: Adults

D-frame net, dip net

Survey Period: From first week of January to fourth week of December

Time of Day: Daytime
Water Level: Low Water Levels
Water Turbidity: Low Turbidity
Survey Method Comment: Larvae

Exuvia survey

Survey Period: From fourth week of May to second week of August

Time of Day: Daytime
Survey Method Comment: Adults/Larvae


Survey References

  • Foster, S.E. and D.A. Soluk. 2004. Evaluating exuvia collection as a management tool for the federally endangered Hine's emerald dragonfly, Somatochlora hineana Williamson (Odonata: Cordulidae). Biological Conservation 118: 15-20.
  • Martin, J.E.H. 1977. The Insects and Arachnids of Canada (Part 1): Collecting, preparing, and preserving insects, mites, and spiders. Publication 1643. Biosystematics Research Institute, Ottawa.

Technical References

  • Dunkle, S.W. 2000. Dragonflies through Binoculars. Oxford University Press, Oxford. 266pp.
  • Evers, D.C. 1994. Endangered and Threatened Wildlife of Michigan. The University of Michigan Press, Ann Arbor. 412pp.
  • Louton, J.A. 1982. Lotic dragonfly (Anisoptera: Odonoata) nymphs of the Southeastern United States: identification, distribution, and historical biogeography. A Dissertation, The University of Tennessee, Knoxville. 357pp.
  • McCafferty, W. P. 1981. Aquatic Entomology: The fisherman's and ecologists' illustrated guide to insects and their relatives. Jones and Bartlett Publishers, Boston. 448pp.
  • Merritt, R.W. and K.W. Cummins. 1996. An introduction to the aquatic insects of North America, 3rd ed. Kendall/Hunt Publishing Company, Dubuque. 862pp.
  • Walker, E. M. 1958. The Odonata of Canada and Alaska, Vol. 2: The Anisoptera- Four Families. University of Toronto Press, Toronto. 318pp.