Two New Gomphus (Odonata: Gomphidae) from Eastern North America with Adult Keys to the Subgenus Hylogomphus

Watershed-Mediated Ecomorphological Variation: A Case Study with the Twin-Striped Clubtail Dragonfly (Hylogomphus geminatus)

“…If smaller individuals west of the river are able to cross it, they may not have success breeding in the presence of larger, more dominant individuals in the east, so the population in the east would still contain mostly larger individuals' genes. This is a pattern that has been noted in the literature since the late 1970s [19]. DNA would need to be collected to assess the impact genotypic differences may have on size.…”

“…Those pollutes may have been in the Apalachicola River drainage since the original species description of H. geminatus . Populations of H. geminatus directly west of the Apalachicola River have consisted of smaller individuals [ 19 ] which is especially concerning given that more than half of the area within the subbasins to the immediate west of the river is comprised of agricultural land. Not only does agricultural development reduce the number of viable streams in which H. geminatus can live through direct waterway modification, it also reduces the amount of upland/sandhill habitat that deposits the sediments into the streams on which H. geminatus is so dependent.…”

“…One known ecomorphologically variable odonate is Hylogomphus geminatus (Carle, 1979) the Twin-striped Clubtail (Gomphidae), a semivoltine species [18] (p. 219) that primarily inhabits relatively small, sandy-bottomed streams across the panhandle of Florida and surrounding areas along the Gulf Coast of the United States. In Carle's original description of H. geminatus [19], he noted differences in body length in adults from populations on either side of the Apalachicola River, Florida, but did not suggest any mechanisms for these differences [19]. Subsequent unpublished observations have noted these differences in H. geminatus as well [20].…”