Calvert County (MD) Dragonflies & Damselflies: Part 5 - Dragonfly Family Gomphidae

Family: Gomphidae (Clubtails/Spinyleg/Dragonhunter)

The Ashy Clubtail is the only member of this family that is represented for Calvert County in the iNaturalist database and that is from a single observation. Richard Orr’s database has four species from the Gomphidae family listed as being present in Calvert County. The discrepancy between databases is even greater for St. Marys and Charles Counties. St. Marys County currently has zero observations in iNaturalist and six species present in Richard Orr’s database. Charles County has three species observations in iNaturalist and Richard Orr’s database contains eight species present for the county.

Listed below are the species within this family that have been observed in at least one of the southern Maryland counties and a comparison of the two databases is made (as of January, 2020). Included with each species is a note extracted from the book “Natural History of DelMarVa Dragonflies and Damselflies” by Hal White (reference 1). Also included is information on three species that were observed at the Cove Point LNG Property and reported in “2011-2012 Survey of the Dragonflies and Damseflies (Odonata) of the Cove Point LNG Property Calvert County, Maryland” by Richard Orr (reference 2)

Unicorn Clubtail/Arigomphus villosipes
The unicorn name is derived from a small horn that protrudes between the eyes. (1)
iNaturalist research grade observations: ​Calvert = 0​ St. Marys = 0​​ Charles = 2 (June)
MD Biodiversity (i.e., Richard Orr):​ Calvert – present St. Marys – X ​ Charles - present

Black-shouldered Spinyleg/Dromogomphus spinosus
Dragonflies regulate their body temperature by varying their body orientation with relation to the sun. On cool days, they will perch with their body and wings perpendicular to the sun in order to maximize their exposure to the sun. On warm days they will point their abdomen towards the sun to minimize heating or move to a shady area. (1)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – X St. Marys – present​ Charles – X

Cobra Clubtail/Gomphurus vastus
This species has not been observed on the DelMarVa Peninsula. (1)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – X St. Marys – X​ Charles - present

Dragonhunter/Hagenius brevistylus
Prefers to eat large insects such as butterflies and other species of dragonflies. It is the largest clubtail dragonfly and has been called the Tyrannosaurus rex of the dragonfly world. (1)
Cove Point adult abundance and flight period – rare/16-June. (2)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 2 (June)
MD Biodiversity (i.e., Richard Orr): ​Calvert – present St. Marys – present​ Charles - present

Lancet Clubtail/Phanogomphus exilis
Emerges on muddy banks close to the waterline and takes approximately an hour before it is able to fly. Unfortunately this makes it very susceptible to wave action from passing boats and is usually unable to recover. (1)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 3 (May-Jun)
MD Biodiversity (i.e., Richard Orr):​ Calvert – X St. Marys – present​ Charles - present

Ashy Clubtail/Phanogomphus lividus
The largest insect ever known was Meganeura monyi, a fossilized Permian dragonfly found in France with a wingspan of over two feet. (1)
Cove Point adult abundance and flight period – uncommon/23-Apr to 04-May. (2)
iNaturalist research grade observations:​ Calvert = 1 (July) St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – present St. Marys – present ​ Charles - present

Sable Clubtail/Stenogomphurus rogersi
S2 State Rare (see below for definition)
There are only three known populations known on the DelMarVa Peninsula, two of which were only discovered since 2007. (1)
Cove Point adult abundance and flight period – rare/10-May to 14-Jun. (2)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – present St. Marys – present​ Charles - present

Eastern Least Clubtail/Stylogomphus albistylus
Research has determined that this clubtail has at least a three year life cycle with nearly all of it as aquatic nymphs. (1)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – X St. Marys – present​ Charles - present

Russet-tipped Clubtail/Stylurus plagiatus
S3 Watch List (see below for definition)
Most clubtails fly in spring and early summer, but this species emerges in late summer to fall. (1)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – X St. Marys – X​ Charles - present

Definitions from the Maryland Department of Natural Resources “List of Rare, Threatened, and Endangered Animals of Maryland”:
S2 - Imperiled / State Rare — At high risk of extinction or extirpation due to restricted range, few populations or occurrences, steep declines, severe threats, or other factors. Typically occurring in 6-20 populations.

S3 - Vulnerable / Watchlist — At moderate risk of extinction or extirpation due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors. Typically occurring in 21-80 populations.

Anotado por rosalie-rick rosalie-rick, febrero 08, sábado 13:29

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