Plants and Animals

Ophiogomphus howei Pygmy snaketail

Key Characteristics

Adults average 1.3 inches (3.3 cm) long. The Pygmy snaketail is very small for a snaketail. The species is bright green on the sides and top of thorax. The inner 1/2 (male) to 2/3 (female) of hindwing is yellow. The yellow abdominal top spots are all triangular and of various sizes. Segment 10 with no top spots. Legs black.

Status and Rank

US Status:
State Status: T - Threatened (legally protected)
Global Rank: G3 - Vulnerable
State Rank: S1 - Critically imperiled

Occurrences

CountyNumber of OccurrencesYear Last Observed
Iron21997

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 - erosional and depositional small cold streams. Requires big rivers with high water quality and stable flow. Proximal to rapids or to surface-breaking structure such as cobble, boulder, or deadwood. Males patrol over stream riffles, flying in an undulating fashion.

Specific Habitat Needs

Sand, coarse cobble needed in: Headwater Stream (1st-2nd order), RiffleHeadwater Stream (1st-2nd order), RunMainstem Stream (3rd-4th order), RunMainstem Stream (3rd-4th order), Riffle.

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

Habitat degradation is major threat including impoundment of rivers, poorly drained roads, channelization, toxic or organic pollution, exotic species. Larvae are especially intolerant of water conditions downstream from dams.

Active Period

Survey Methods

An exuvia survey consists of searching the banks and protruding rocks of rapid streams for the cast skin of dragonfly larvae. Adults are most active during the day, disappearing in late afternoon and not reappearing till late morning the next day, peak activity is from 2:30 to 3:30 pm. Adults forage primarily in the treetops on sides of river valleys, but occasionally in riverside trees, or even on low plants in nearby fields. Males patrol with a bouncy flight over rippling water, but not over pools or rapids. Females are easier to see than males because they display their tinted hindwings by holding them vertically much of the time during flight.

D-frame 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: Larva

Aerial net, visual survey

Survey Period: From fourth week of April to fourth week of June

Time of Day: Afternoon
Survey Method Comment: Adults

Exuvia survey

Survey Period: From fourth week of April to fourth week of June

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

References

Survey References

  • 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

  • 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.