Dragonflies of the genus Ophiogomphus are referred to as Snaketails and Ophio actually means "serpent" (Mead 2003). They get their name from the repeated color patterns on their abdomens which give them a snake-like appearance (Dunkle 2000).
There are 21 extant occurrences in New York State, with no population estimates determined. Future survey efforts may result in the identification of additional populations.
There is no estimate of population size for this species based on statewide occurrences. State occurrences have been reported since the early 1990's in fast-flowing streams and rivers with a rocky and sandy substrate (New York Natural Heritage Program 2020). Any new location information on the Brook Snaketail in New York may be reflective of heightened interest in surveying for this species rather than a population increase or a range expansion (Holst 2005).
There are three known historical occurrence of Brook Snaketail in New York State. Twenty-one extant occurrences have been noted in St. Lawrence, Franklin, Essex, Warren, Washington, Montgomery, Rensselaer, Columbia, Dutchess, Orange, Sullivan, and Ulster counties. Population size has not been determined for these extant occurrences but is estimated to be relatively stable (New York Natural Heritage Program 2020).
Any activity which might lead to water contamination or the alteration of natural hydrology could impact Brook Snaketail populations (Holst 2005). Such threats might include roadway and agricultural run-off, industrial pollution, the building of dams, logging activity, development near their habitats, and littering (Natural Heritage Endangered Species Program 2003, Holst 2005).
Any efforts to reduce agricultural run-off, salt run-off from roadways, flow manipulation, development of upland stream borders, and contamination of fast-flowing streams should be considered when managing for this species (Natural Heritage Endangered Species Program 2003, Holst 2005).
Further research is needed to define the distribution and population size of the Brook Snaketail. In addition, research is required to understand the habitat requirements and threats to this species, and to create appropriate management guidelines for its persistence in known locations (Holst 2005).
The Brook Snaketail inhabits clear, rapid-flowing streams that are shallow with a sandy and rocky substrate (Dunkle 2000, Needham et al. 2000). They are often found near riffles of open areas of the stream where the banks are brushy (Dunkle 2000). They also may be found in fast-flowing areas of larger rivers with similar substrate (New York Natural Heritage Program 2020).
The Brook Snaketail has been confirmed in locations from 13 counties from the eastern portion of the state. While no population estimate has been made, they are known to occur in clear, fast-flowing streams and rivers with rocky and sandy substrate (New York Natural Heritage Program 2020, Donnelly 2004). More inventories are needed to determine the full extent of its statewide range (Holst 2005).
Although it is common and localized, the Brook Snaketail is spottily distributed across the northeastern United States and Great Lakes (Nikula et al. 2003). It has a substantial total known range from New Brunswick, Nova Scotia, and Quebec as well as Michigan, Maine, New Hampshire, Vermont, New York, Massachusetts, Rhode Island, Connecticut, New Jersey, Virginia, North Carolina, and Kentucky (Abbott 2007).
Snaketails are characterized by their bright green thorax and are part of the Clubtail family. As their name suggests, Clubtails have an enlarged tip on the end of their abdomens, giving them a club-like appearance. The Brook Snaketail has narrow, brown stripes on its green thorax and has a black abdomen with yellow dorsal (top) markings (Needham et al. 2000, Nikula et al. 2003). Brook Snaketail adults have a bright green thorax with narrow, brown stripes. They are 1.7-1.9 inches in length. They have green eyes and, as with all Gomphids, their eyes are separated dorsally. Legs can be either all black or may have a pale stripe on the tibia. They have a slender, black abdomen with a moderately widened "club" at the end and yellow triangular dorsal markings on abdominal segments 2-8. Yellow, rounded side spots are present on abdominal segments 9 and 10. The terminal appendages of the male are yellow and distinctive in shape from other snaketails when examined under magnification. Female Brook Snaketails have thicker abdomens than males, and their subgenital plates are about two-thirds as long as abdominal segment 9.
Gomphid larvae spend much of their time burrowing into the substrate of streams and rivers where they are found. Adults can be found perching on the ground, on emergent rocks in streams and rivers, or on leaf surfaces (Nikula et al. 2003). They also use upland borders of streams for feeding and resting (Natural Heritage Endangered Species Program 2003). Adult females oviposit by tapping their abdomens onto the surface of swift-flowing water while simultaneously releasing eggs (Nikula et al. 2003, Mead 2003).
Brook Snaketail larvae feed on smaller aquatic invertebrates and adults feed on insects which they capture in flight.
Adults are active from late April through late August but the best time to see them is probably June or July (Dunkle 2000, Nikula et al. 2003). Larvae may be found in appropriate aquatic habitats year-round.
The time of year you would expect to find Brook Snaketail present and reproducing in New York.
Ophiogomphus aspersus Morse, 1895
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This guide was authored by: Erin L. White
Information for this guide was last updated on: July 21, 2020
Please cite this page as:
New York Natural Heritage Program. 2020. Online Conservation Guide for Ophiogomphus aspersus. Available from: https://guides.nynhp.org/brook-snaketail/. Accessed October 20, 2020.