streamsurfer's Identifications

This nymph and others of the same species not shown here were in small mucky pools along the main channel of a tiny, sand-bottomed, headwater stream in mostly shaded riparian oak-pine woods.

Features visible in the photos that indicate Spiketail (Cordulegastridae) according to Tennessen (2019) include a large mask-like labium with jagged teeth, divergent wing sheaths, long setae on many parts of the body, elongate body with sharply pointed abdomen tip, and paired dark spots on the abdomen along each side of the midline. Features that indicate Twin-spotted Spiketail (Cordulegaster maculata) include all pale frontal setae that get shorter gradually from the midline toward each outer edge (Photo 2), posterior edge of the prementum with distinctly V-shaped concavity that makes the midline groove start well in from the posterior edge of the prementum (Photo 3 & 4), and lateral spine on S8 points mostly rearward at the same angle as the spine on S9 (Photo 5). Adults of Cordulegaster maculata have been observed along this stream: https://www.odonatacentral.org/index.php/SubmissionAction.get/submission_id/493656.

These nymphs were in small mucky seeps that fed into a tiny, sand-bottomed, headwater stream in mostly shaded riparian and oak-pine woods.

Features visible in the photos that indicate Spiketail (Cordulegastridae) according to Tennessen (2019) include a large mask-like labium with jagged teeth, divergent wing sheaths, long setae on many parts of the body, elongate body with sharply pointed abdomen tip, and paired dark spots on the abdomen along each side of the midline. Features that indicate Sarracenia Spiketail (Cordulegaster sarracenia) include a distinct tuft of long setae at the middle of the frontal shelf (Photos 2 & 6), posterior edge of the prementum with a shallow concavity that makes the midline groove start near the posterior edge of the prementum (Photos 3, 4, 7, & 8), and lateral spine on S8 pointing upward at a steeper angle than the spine on S9 (Photo 9). Adults of Cordulegaster sarracenia have been observed along this stream: https://www.odonatacentral.org/index.php/SubmissionAction.get/submission_id/494102.