Plants and Animals
Stylurus notatus Elusive snaketail
Key Characteristics
Adults average 2.4 inches (6.1 cm) long. The Elusive snaketail has two black thoracic side stripes on a yellow background. Abdominal top spots are very small on segments 4-6, broader in 7 and 8, and absent, or greatly reduced, in 9 and 10. Yellow side spots on segments 7-10; those on 8 and 9 are larger. Upper part of male's face is black. Moderately clubbed tail. Blue eyes.
Status and Rank
US Status: No Status/Not Listed
State Status: T - Threatened (legally protected)
Global Rank: G3 - Vulnerable
State Rank: S1S2 - Rank is uncertain, ranging from critically imperiled to imperiled
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Benzie | 1 | 2013 |
| Houghton | 2 | 2001 |
| Manistee | 1 | 1999 |
| Mecosta | 1 | 2005 |
| Missaukee | 1 | 2006 |
| Saginaw | 1 | 2012 |
| St. Clair | 1 | 1983 |
| Wayne | 3 | 2011 |
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.
Habitat
lotic - depositional and lotic - littoral. Clear rivers with moderate current and gravel or sandy benthos. Sediments, primarily silt, gravel or sand substrates. Adults can be found in river/stream/riaprian/floodplain corridors or over the lake. This species makes long excursions along surface of the river and rarely approaches land. Rivers (usually large) and large lakes, often with sandy bottoms, sometimes also with silt and gravel.
Specific Habitat Needs
Sandy substrate needed in: Headwater stream (1st-2nd order), riffle; Inland lake, littoral, benthic; Mainstem stream (3rd-4th order), run; Mainstem stream (3rd-4th order), riffle; River (5th-6th order), run; River (5th-6th order), riffle;
Silt, gravel, sand needed in: Headwater stream (1st-2nd order), run;
Natural Community Types
- Headwater stream (1st-2nd order), riffle
- Headwater stream (1st-2nd order), run
- Inland lake, littoral, benthic
- Mainstem stream (3rd-4th order), run
- Mainstem stream (3rd-4th order), riffle
- River (5th-6th order), run
- River (5th-6th order), riffle
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 siltation and cause a decrease in dissolved oxygen.
Survey Methods
An exuvia survey consists of searching the banks and protruding rocks of rapid streams for the cast skin of dragonfly larvae. Adults fly long, swooping forays far out over open water, difficult to catch by net. Adults, when they do perch, do so high up in nearby trees. Females descend from their flights over open water to deposit eggs into the lake. Most males patrol from 12 to 3 pm.
Aerial net, visual survey
Survey Period: From first week of June to first week of October
Time of Day: Afternoon
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 second week of June to fourth week of August
Time of Day: Daytime
Survey Method Comment: Larva/Adult
References
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.
- 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.
- Mead, K. 2003. Dragonflies of the North Woods. Kollath-Stensaas Publishing, Duluth. 203pp.
- 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.
- NatureServe. 2005. NatureServe Explorer: An online encyclopedia of life [web application]. Version 4.5. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer
- Walker, E. M. 1958. The Odonata of Canada and Alaska, Vol. 2: The Anisoptera- Four Families. University of Toronto Press, Toronto. 318pp.