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.
The beautiful brook snaketail dragonfly (Ophiogomphus aspersus) is listed as a species of special concern in New Jersey. A Threatened status listing has been proposed by the Endangered and Nongame Species Advisory Committee; however, no formal rule proposal has been filed to date.
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In what is hoped will be the first of many articles about odonates (dragonflies and damselflies), I would like to highlight the beautiful brook snaketail dragonfly (Ophiogomphus aspersus). The Latin root Ophio means snake-like or serpent, hence the very appropriate common name applied to this group. The snaketails were given this name because males have sinuous or snake-like claspers at the end of the abdomen which are used during mating.
Snaketails belong to the greater clubtail family (the Gomphids). All clubtails have widely spaced eyes that do not touch at any point. Most have a widening at the tip of the abdomen, also called a club. While most clubtails have simple patterns or dull coloration, the snaketails are mostly bright green. Other color patterns vary subtly, but they are stunning insects and among our most beautiful dragonflies. The majority of clubtails inhabit rivers and streams.
Many North American species are declining or are severely imperiled due to water quality degradation. Toxic run-off, siltation from erosion and the construction of dams are among the greatest threats facing clubtails and other odonates. The snaketails are generally the most sensitive to any environmental changes. Even minor increases in the silt or mud content in streams can alter dissolved oxygen levels and harm or kill snaketail larvae. Like most odonates, snaketails also need undisturbed fields and wooded uplands adjacent to breeding waters. It is here that critical foraging and breeding occurs. This habitat also provides vital shelter for fragile newly emerged adults during severe weather events and protects them from predators.
Of the four snaketail species known to breed here, the rarest is the brook snaketail. The first New Jersey colony was not discovered until 1986 in the Whippany River watershed in Morris County. Since then, an additional four colonies have been found in the Skylands and Ridge and Valley regions. This highly localized species also inhabits small segments of the Musconetcong, Wallkill and Flat Brook watersheds.
The brook snaketail has very specific habitat requirements while the other three related species are slightly more elastic. This species inhabits clean, relatively quiet or slow moving streams with an abundance of sandy sediments. It shares this habitat requirement with the federally endangered dwarf wedgemussel and co-exists with it at two locations in New Jersey. It is often associated with the harpoon clubtail (Gomphus descriptus) and river jewelwing (Calopteryx aequabilis). The individual populations of brook snaketail in New Jersey are referred to as colonies due to the limited amount of appropriate habitat in our area. Unlike more common or generalized species, breeding is restricted to relatively small sections of the rivers and streams they inhabit.
Due to the many challenges facing this species, and the small size of the five known colonies, the brook snaketail has been proposed as a threatened species in New Jersey. This species will be carefully monitored to ascertain whether its status is changing. Further colonies are also being sought, particularly in the Ridge and Valley region. A study will be undertaken next year that will hopefully quantify the actual distance from breeding streams that this species travels while foraging. This information will eventually allow for the establishment of effective protective buffers around known brook snaketail colonies and their critical habitat areas.
Rusty Snaketail (Ophiogomphus rupinsulensis) is a widespread snaketail of northeastern and midwestern rivers. This species shows a largely brown abdomen unlike several other Maryland Ophiogomphus. In Maryland, this dragonfly occurs along the Potomac and its larger tributaries, and also on Deer Creek, Harford Co. According to Richard Orr's The Dragonflies and Damselflies of Maryland and the District of Columbia, it is common on the upper section of the Potomac, while it remains uncommon elsewhere in the state.
Habitat: This is an uncommon species that is known to be found in Wisconsin and along the east coast from West Virginia to Maine, especially along Appalachian Mountains. Pygmy snaketails like clean big rivers with clear, fast-moving water and gravel/sand bottoms. They are rarely found in small rivers. It also seems that they cannot breed below dams due to the altered habitat conditions. In Wisconsin, it has been infrequently found in northern counties.
Adults average 1.7 in long. The species has a bright green thorax with side stripes which form a conspicuous N-shape just above the leg bases. Face and occiput are green. There are heavy, black crosslines on face with the upward-arching lower line interrupted. The female snaketail has a pair of small, upright, black "horns" in the center of the occiput. Abdomen is mostly black with long, yellow top spots; spots on 7 and 8 are shorter. Segments 9 and 10 each show a round spot. Sides of segments 7 to 10 with variously shaped yellow spots. Legs black.
Two similar-looking snaketail (Ophiogomphus) species are found in Arizona: the Arizona (O. arizonicus) and thePale (O. severus) Snaketails. The Arizona Snaketail is found in several counties across the middle of the state and the Pale Snaketail is restricted to streams of the Chuska Mountains, Apache Co. The two species could potentially coexist at a same location but this has not been observed to date.
The only snaketail in Europe; resembles a large clubtail in general coloration and river habitat, but the 'front-end' is vivid apple green in mature individuals and the male appendages are short.[4] It is the largest of the Gomphidae apart from Bladetail, with green eyes and 'face, and green thorax with thin black lines on top and side, the latter similar to those on Yellow Clubtail and Western Clubtail; at the base of abdomen the green is extending to S2, the rest of the abdomen has a discontinuous yellow pattern to S 10, generally broader than on clubtails and those on S3-7 more triangular in shape, and moderately clubbed at S8-9. The legs are extensively yellow. Males appendages are short and yellowish. Female yellow markings on the abdomen are broader than on males. It shows two tiny 'crests' on the back of the head, between eyes. Black lines on the thorax reduced in some individuals. Immatures lack any green.[4]
Bison Snaketail is one of four species ofsnaketail in California, but the only one in MTY. Males have expanded'clublike' tips to the abdomen (like a cobra hood) and the abdomen is acolorful yellow and black. Bison Snaketail has a bright green throaxwith a broad dark-brown stripe across the side. Males sit on rocks inthe current, waiting for females or disputing other males, often withraised abdomens.
Before 2007, there were only two records ofBison Snaketail in Monterey County. P.H. Arnaud, Jr., collected singleson successive days at "Big Sur State Park" on 19 & 20 June 1949. Itis assumed this was Pfeiffer-Big Sur State Park, and presumably thesnaketails were along the Big Sur River. The first one, a female inpoor condition on 19 June 1949, is now #8934 in the collection atIllinois State University. The second is now held at the CaliforniaAcademy of Sciences, San Francisco. [ThankstoTim Cashatt, curator at Illinois State Univ., and Tim Manolis forthese details.]
St. Croix Snaketail (Ophiogomphus susbehcha) has an interesting history in Maryland. For a number of years, unidentified early-emerging Ophiogomphus were known from the Potomac and one or two other rivers in the region. A male specimen was collected from Frederick Co. by Richard Orr in 2002, and a fair number of exuviae were collected over the next decade or so. As more adult specimens were collected, and the known range was expanded to include the James River in Virginia, the snaketail compared to other Ophiogomphus, and was found to be extremely close to Ophiogomphus susbehcha of Wisconsin. The eastern individuals differed primarily in smaller size than that of the types. The eastern snaketails ('Chesapeake Snaketail') are now considered by several experts to be conspecific with susbehcha, but perhaps warranting a subspecific designation (Richard Orr's account of the discovery and identification progress at ). This species in Maryland is known only from the Potomac River in Frederick Co., and is consequently ranked as S1 (highly state rare). e24fc04721
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