Calopterygoidea, Selys-Longchamps, 1850

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 : 8

4.1.5.2. ‘ Calopterygoidea ’ group 2

(BS = 100, PP = 1, QS = 0.47/0.44/ 0.97).

Nine families make up Group 2. Included in these nine families, we propose two new families ( Mesagrionidae , Protolestidae ) and co recognize Tatocnemididae as at the family level (see below Family-level revisions to the Classification of Zygoptera ). Seven of these families are unique morphologically and contain either a single genus ( Pentaphlebiidae , Hypolestidae , Mesagrionidae , Protolestidae and Tatocnemididae) or two genera ( Dicteriadidae and Philogeniidae ). Our new phylogenetic hypothesis has no taxonomic consequences regarding the existing families, except for Heteragrionidae , which is expanded to include the genera Dimeragion and Heteropodagrion . With this addition to Heteragrionidae there are now two families with more than two genera; Heteragrionidae with four genera and Polythoridae with seven genera. With the exception of a well-supported cluster of three Afrotropical families (Tatocnemididae, Protolestidae and Pentaphlebiidae ; BS = 100, PP = 1, QS = 0.74/0.29/0.97) Group 2 is largely Neotropical. The relationships between the families are difficult to determine from a morphological and/or behavioural perspective as they have few characters in common. Further, although the clade is well supported overall, the relationships between many of the families are not well supported due to low QS values. This is a clade where additional taxon sampling throughout the clade itself and throughout the “calopterygoidea” in general is likely to reveal much more clarity towards the overall classification.

Protolestidae (BS = 100, PP = 1, QS = 1/NA/1) and Tatocnemididae are here recognised as distinct families (see below Family-level revisions to the Classification of Zygoptera ) as they have no clear relatives and are quite distinct in adult and nymphal morphology from their closest relative, Pentaphlebiidae . Both Protolestes (eight species described) and Tatocnemis (ten species) are restricted to rainforest streams in Madagascar, were until recently included in Megapodagrionidae , and are poorly known and in dire need of taxonomic revision. Adults of both genera perch with wings variably closed or (half) open and the abdomen held roughly horizontal. Protolestid nymphs have fan-shaped caudal gills, a character only shared with the distantly related Argiolestidae ( Kalkman et al., 2010) and Mesopodagrionidae ( Yu 2016) , while adults have a rather wide and slender head, similar to some members of the unrelated Platycnemididae . Based on morphology, Tatocnemididae is not similar to other families: the potential apomorphy of crenulated wing tips is shared only with some genera of the unrelated Platycnemididae . The nymph has inflated saccoid caudal gills bearing a terminal filament as foundin several other families of Zygoptera . Tatocnemididae were originally described by R´acenis (1959) as a subfamily of Megapodagrionidae to include Tatocnemis and Archaeopodagrion , but are now restricted to the genus Tatocnemis .

The endemic species Mesagrion leucorhinum from the Colombian Andes is found as sister to two small families, Dicteriadidae (two genera each with a single species from the Amazonian region) and Hypolestidae (one genus, three species from the Greater Antilles), but with low QS values (BS = 100, PP = 1, QS = -0.45/0.28/0.99). Both of these families have well defined apomorphies, are fairly distinctive and do not seem particularly close to M. leucorhinum from a morphological or behavioral perspective. Mesagrion leucorhinum was not included in previous molecular analyses ( Bybee et al., 2008; Davis et al., 2011; Dijkstra et al., 2014; Dumont et al., 2010; van Tol and Reijnen, 2009), but based on morphology it was tentatively placed in an Incertae Sedis group together with Dimeragrion and Heteropodagrion . In our analyses Mesagrion is not found to be close to these genera. As there are no other likely candidates to be the closest relative of Mesagrion , we propose to regard it as a family in its own right Family-level revisions to the Classification of Zygoptera . Apomorphies for this family (although not unique within Zygoptera ) are the scarcely sclerotized dorsum of segment eight in the female and the long paraprocts which are serrated at the distal fourth of the dorsal margin ( Garrison et al., 2010; P´erez-Guti´errez and Montes-Fontalvo, 2011). The species rests with its wings closed, which was regarded as an additional indication that Mesagrion was close to Heteropodagrion , but it is now clear that this habit evolved several times within the families previously grouped into ‘Calopterygoidea’.

Recent hypotheses proposed Heteragrionidae to be composed of two South American genera: Heteragrion and Oxystigma ( Bybee et al., 2008; Davis et al., 2011; Dijkstra et al., 2014; Dumont et al., 2010; van Tol and Reijnen, 2009). In their Bayesian analyses ( Dijkstra et al., 2014), the South American genera Dimeragrion and Heteropodagrion were found to be sister to Heteragrionidae and would have been included too were it not for the ML analyses which showed these two genera to be close to Heteragrionidae but with Rimanella (Rimanellidae) and Heliocharis (Dicteriadidae) intermingled. In our analyses Dimeragrion and Heteragrion form a monophyletic group (BS = 100, PP = 1, QS = 1/NA/1) suggesting that Dimeragion and Heteropodagrion indeed should be included as members of Heteragrionidae . In this new definition, the Heteragrionidae include four genera from tropical South-American: Dimeragrion (5 species), Heteragrion (56 species), Heteropodagrion (5 species) and Oxystigma (3 species). With the exception of Heteropodagrion all these genera have their wings open at rest. The caudal gills of the nymphs of Heteragrion , Heteropodagrion and Oxystigma are saccoid witha constriction at about ¾ length witha slender apical filament. The caudal gills of the nymph of Dimeragrion are nearly flat ( De Marmels, 1999), but do have a terminal filament and are slightly inflated with a thickened dorsal keel making them three-dimensional ( Tennessen, 2010).

The last family included in this section of the ‘Calopterygoidea’ is Polythoridae (BS = 100, PP = 1, QS = 1/NA/1) which has several apomorphies in the nymphal stage such as lateral abdominal gills on the second to seventh segment, dorsal abdominal knobs and swollen caudal gills with angular or finger-like projections. The molecular revision of the family by Sanchez Herrera et al. (2018) showed that the family is monophyletic. The lateral abdominal gills of the nymphs are reminiscent of those of Euphaeidae , which has led to the suggestion that these families might be related. Our phylogeny shows clearly that these two are not close and that lateral abdominal gills evolved at least twice within Zygoptera .