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

  • State Status: SC
  • State Rank: S1S2
  • Global Rank: G3


County NameNumber of OccurrencesYear Last Observed
Distribution map for Stylurus notatus

Updated 5/15/2018. 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 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, Mainstem Stream (3rd-4th order), Riffle, Mainstem Stream (3rd-4th order), Run, River (5th-6th order), Riffle, River (5th-6th order), Run, Inland Lake, Littoral, Benthic Silt, gravel, sand needed in Headwater Stream (1st-2nd order), Run

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.


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.

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at [Accessed Sep 23, 2018]


Survey References

Technical References

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