Calvert County (MD) Dragonflies and Damselflies: Part Nine – Dragonfly Family Corduliidae

Family: Corduliidae
This is another family of dragonflies that is severely under-represented in the southern Maryland iNaturalist observational database. There is but a single observation in total for the three counties and that is for a Common Baskettail observed in Calvert County. Of the nine species listed below for southern Maryland from Richard Orr’s database, all nine can be found in Charles County, five of the species in St. Marys County, and five in Calvert County. A major consideration is that five of the nine species are listed on the Maryland Department of Natural Resources “List of Rare, Threatened, and Endangered Animals of Maryland”. So while much work remains to be done in order to bring the iNaturalist observations closer to the definitive database of county sightings, the rarity of many of these species will probably require a specialized effort to find them.

Listed below are the species within the Corduliidae 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). As was done with the previous family, I have included with each species a note extracted from the book “Natural History of DelMarVa Dragonflies and Damselflies” by Hal White (reference 1). Of particular relevance for Calvert County, I have also included information on the four species of this family 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).

Common Baskettail/Epitheca (Tetragoneuria) cynosura
All damselflies and some dragonflies (darners) oviposit by using a sharp ovipositor to deposit their eggs within tough plant tissue. The thought is that most dragonfly families evolved away from this mechanism of egg laying. The female Common Baskettail extrudes her eggs into a gelatinous mass which becomes attached to floating objects in the water. (1)
Cove Point adult abundance and flight period – common/01-Apr to 14-Jun. (2)
iNaturalist research grade observations:​ Calvert = 1 (Apr) St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – present St. Marys – present ​ Charles - present

Prince Baskettail/Epitheca (Epicordulia) princeps
Dragonflies are aquatic insects for most of their lifecycle, but as adults they transition into terrestrial insects. Dehydration in the adults becomes a major problem throughout their terrestrial period. (1)
Cove Point adult abundance and flight period – rare/04-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

Robust Baskettail/Epitheca (Tetragoneuria) spinosa
S1/S2 State Rare (see below for definition)
Baskettails underwent a classification revision in 1966 although not everyone has yet to accept the proposed revision. (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

Selys’ Sundragon/Helocordulia selysii
S2 State Rare (see below for definition)
The first known specimen of this species was collected in DelMarVa in 1937. It would be almost 70 years before the second record of the species was made in DelMarVa in 2006. (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

Uhler’s Sundragon/Helocordulia uhleri
This species has not been recorded for the DelMarVa peninsula. (1) It is only known from four counties within all of Maryland.
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – X St. Marys – X Charles - present

Fine-lined Emerald/Somatochlora filosa
S2 State Rare (see below for definition)
The Great Cypress Swamp of DelMarVa forms the headwaters of the Pocomoke River and once covered an area of nearly 60,000 acres. The swamp is also known as the Burnt Swamp as a result of an eight year fire within its boundaries. Remnants of the Great Cypress Swamp can still be found in Trap Pond State Park in Delaware and in the Pocomoke River State Park of Maryland. These are among the few places where the Fine-lined Emerald can be found. (1)
Cove Point adult abundance and flight period – rare/29-Aug to 30-Sept. (2)
iNaturalist research grade observations:​ Calvert = 0 St. Marys = 0​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – present St. Marys – X​ Charles - present

Mocha Emerald/Somatochlora linearis
S3 Watch List (see below for definition)
For those interested in creating a life list for dragonflies, it is important to consider visiting different types of sites, different seasons, and even different times of day. (1)
iNaturalist research grade observations:​ Calvert = 0​ St. Marys = 0​​ Charles = 0
MD Biodiversity (i.e., Richard Orr):​ Calvert – present St. Marys – present​ Charles - present

Treetop Emerald/Somatochlora provocans
S1 (see below for definition)
While some Emerald dragonflies are southern in their distribution, the majority are closer to a Canadian distribution and inhabit bogs, peat-stained streams, and alpine lakes. (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

Clamp-tipped Emerald/Somatochlora tenebrosa
Emeralds have a special allure for dragonfly enthusiasts because they are challenging to ID, are generally scarce, and even when present are almost always elusive. (1)
Cove Point adult abundance and flight period – uncommon/16-Jun to 11-Sept. (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

Definitions from the Maryland Department of Natural Resources “List of Rare, Threatened, and Endangered Animals of Maryland”:
S1 - Critically Imperiled / Highly State Rare — At very high risk of extinction or extirpation due to very restricted range, very few populations or occurrences, very steep declines, very severe threats, or other factors. Typically occurring in five or fewer populations.
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.

Publicado por rosalie-rick rosalie-rick, 14 de febrero de 2020

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