Gomphidae, Rambur, 1842

Bybee, Seth M., Kalkman, Vincent J., Erickson, Robert J., Frandsen, Paul B., Breinholt, Jesse W., Suvorov, Anton, Dijkstra, Klaas-Douwe B., Cordero-Rivera, Adolfo, Skevington, Jeffrey H., Abbott, John C., Herrera, Melissa Sanchez, Lemmon, Alan R., Lemmon, Emily Moriarty & Ware, Jessica L., 2021, Phylogeny and classification of Odonata using targeted genomics, Molecular Phylogenetics and Evolution 160, pp. 107115-107115 : 11

4.1.10. Gomphidae and Petaluridae

(BS = 97, PP = 1, QS = 0.22/ 0.47/0.92)

Past phylogenetic reconstructions have debated whether Gomphidae are sister to Libelluloidea or Petaluridae ( Bybee et al., 2008; Carle et al., 2015; Dumont et al., 2010; Letsch et al., 2016 ab), with even large transcriptome datasets recovering both possibilities with high probability (Kohli et al.). Despite some uncertainty in the relationship of Petaluridae + Gomphidae based on BS measures of nodal support, quartet sampling provides moderately high support for this node. It is unlikely that additional molecular data will resolve this node in such a way that traditional nodal support measures (PP, SS) will increase. The next step in higher-level classification as it relates to this node is a much deeper taxon sampling to provide a test that might finally provide both the phylogenetic signal and statistical support to reconstruct this relationship. This relationship is of interest in part because it influences our interpretation of the evolution of exophytic oviposition (not using plant material). Due to a reduction in the ovipositor, gomphids have exophytic oviposition ( Sahl´en, 1995). Reduction in the ovipositor, perhaps convergently shared with the Gomphidae , is a prominent feature of Libelluloidea . The ovipositor of Aeshnoidea and Petaluridae (and Zygoptera ) comprises three pairs of ventral processes. The first and second pairs (anterior and posterior gonapophyses) are enclosed by the third (gonoplacs). In gomphids, libelluloids and cordulegastroids the ovipositor is modified for exophytic oviposition ( Carle, 1995; Tillyard, 1917). In Cordulegastridae , the third processes (gonoplacs) are vestigial. In Synthemistidae s.L. clade, the third processes are absent and at least the second processes are reduced, although in some taxa the first pair is present and nearly as long as in Cordulegastridae . In Macromiidae , Corduliidae and Libellulidae , the first processes are reduced to small flaps and the other structures are apparently absent except for the probable vestige of the styli emerging directly from the 9th sternite ( Tillyard, 1917). In a few instances, the 8th (e.g., some Somatochlora ) or 8th and 9th sternites ( Uracis ) are secondarily produced to form an ovipositor in Macromiidae , Corduliidae and Libellulidae species.

The monophyly of both Petaluridae and Gomphidae were never really in doubt and both are fully supported as monophyletic. The groups stand in stark contrast to each other in terms of both diversity and distribution. The petalurids comprise 11 species, uniquely distributed towards the edges of the United States, Chile, Japan, New Zealand and Australia. Nymphs tend to have long generation times, often remaining in the nymphal stages for up to five years while living along river banks or as burrowers or rarely as semi-terrestrial hunters of high mountain bogs ( Ware et al., 2014). Adults are drab in colour, usually large in size, and tend to be found near forest edges, often perching on tree trunks. In contrast, Gomphidae are incredibly species rich, comprising over 1000 extant species. Adults are heterogeneous in their colour, shape and size, often perching on the ground or just above the water on overhanging branches or vegetation or even tree-tops. Nymphs exhibit an array of morphological forms and tend to use concealment and often burrow just below the stream substrate as ambush predators.