Libelluloidea, Leach, 1815

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 : 12

4.1.12. Libelluloidea

(BS = 100, PP = 1, QS = 0.81/0/1)

Libelluloidea traditionally includes Synthemistidae , Macromiidae , Corduliidae and Libellulidae ( Fraser, 1957) , and is extremely species rich (~1,500 species). We recover this as a well-supported monophyletic group.

Tillyard described Synthemistidae , which were united by synapomorphies both in the nymphal stage (e.g., premental shape, antennal segment number, tibial morphology) and adult stage (e.g., wing venation, male secondary genitalic morphology). However, the family was considered to be variable. Molecular phylogenies ( Letsch et al., 2016 ab; Letsch, 2007; Ware et al., 2007) have suggested that the family should be split, with Archaeophya , Gomphomacromia , Synthemis , Synthemiopsis , Eusynthemis often recovered as a clade, with Austrocordulia , Micromidia , Lathrocordulia , Macromidia , Cordulephya recovered either as a paraphyletic group or a separate clade. Here, we recover a fully supported grouping of Gomphomacromia , Eusynthemis , Choristhemis and Parasynthemis , as clade also recovered by ( Letsch, 2007) and ( Letsch et al., 2016a,b). Cordulephya , Micromidia and Austrocordulia are also recovered as a monophyletic clade (BS = 100, PP = 1, QS = 1/NA/1), sister to the remaining libelluloids. Our findings strongly support the idea of Synthemistidae as a complex group deserving of extensive data collection, but are unclear regarding the number and arrangement of taxa in this group; hence we await further taxon sampling before naming additional clades in this complex.

We recover Epophthalmia , Macromia and Phyllomacromia in a fully supported group (BS = 100, PP = 1, QS = 1/NA/1). Epophthalmia , Didymops , Macromia and Phyllomacromia have routinely been recovered as a monophyletic Macromiidae , first by Gloyd (1959), and again by several molecular studies ( Bybee et al., 2008; Carle et al., 2015; Dumont et al., 2010; Letsch et al., 2016 ab; Letsch, 2007; Ware et al., 2007, in prep.). Nymphal synapomorphies include the shape and dentition of the prementum, the relative length of the hind legs to body size (giving them a “spider-like” appearance), and a frontal horn between their eyes; adult synapomorphies include the shape and size of the anal loop in the hindwing, eyes with a small protuberance on the lateral edge, and secondary penile characters. Macromiidae adults are fast fliers known to patrol long stretches of mainly lotic habitats. Phyllomacromia and Epophthalmia are recovered as sister taxa; this relationship was suggested by May (1997) based on male penile morphology.

Even with a limited sampling of corduliids we demonstrate the complexity of the phylogenetic relationships of this group. Nymphs of the family Corduliidae are difficult to distinguish from Libellulidae , save for a small number of premental characters ( Tennessen, 2019; Theischinger and Fleck, 2003). ( Ware et al., 2007) recovered Aeschnosoma + Pentathemis as sister to the remaining Corduliidae ; these genera have remarkably similar looking nymphs, with long spines on segment nine, despite having ranges in South America and eastern Australia, respectively. Fleck and Legrand (2013) hypothesize that Libellulosoma forms a clade with Aeschnosoma and Pentathemis . Here, we recover Pentathemis as sister to the Libellulidae , but with low bootstrap support (96%) and among the poorest of QC values (-0.76), suggesting that this relationship needs further investigation before confirmation of this grouping. In the absence of Neocordulia , Lauromacromia , Idomacromia , Nesocordulia and other taxa of incertae sedis, we cannot yet address with confidence the broader composition of Corduliidae .

Libellulidae is recovered with full support. However, there is a great amount of discord within the group demonstrated by both the highest concentration and lowest nodal supports across the topology. We recover three extremely poorly supported clades suggesting instead a polytomy among the taxa included in our analyses. However, there are clades within the libellulids that are well supported. The Libellulinae (BS = 100, PP = 0.95, QS = 1/NA/1), a large subfamily is recovered in our analyses and has been consistently recovered in past molecular work. Nannophlebia and Zygonyx were recovered in a clade previously, and here we find support for their sister relationship (BS = 100, PP = 0.96, QS = 0.92/0/1). Ware et al. (2007) found Pantala to be closely related to Zygonyx and Nannophlebia ; here a clade comprising these three taxa is recovered with low QS values (BS = 100, PP = 1, QS = -0.46/0/0.97). Past studies have recovered Rhyothemis in a clade with Sympetrum (e.g., Ware et al., 2007). Herein we also recover this relationship but with the inclusion of never before sequenced Austrothemis (BS = 56, PP = 0.75, QS = 0.17/0.33/0.86). The family Libellulidae is extremely species rich, comprising well over 1,000 species. Many of the members of this family have an elongated, bisected anal loop in their hind wing, and an oblique vein immediately following the nodus. Their secondary penile characters, and general adult and nymphal morphology strongly support the monophyly of this family. Afurther look at this family with a much expanded taxon sampling is necessary to better understand the complex evolutionary history that certainly represents one of the most rapidly radiating lineages in Odonata.