Cylapinae, Kirkaldy, 1903

Monophyly of Cylapinae and their relationships with Psallopinae and Isometopinae

In the previous studies, the monophyly of Cylapinae was considered to be doubtful, because there were no apomorphies for this group ( Namyatova and Cassis 2019a, b). Many representatives of this subfamily share a similar set of characters in the tarsus and pretarsus, i.e. slender tarsi, setiform and asymmetric parempodia, and three rows of tiles on the unguitractor, with those in the middle row acute. However, this set of characters is not unique for Cylapinae , because Psallopinae and Isometopinae have similar structures (e.g. Schuh and Schwartz 1984, Namyatova and Cassis, 2016, 2019b, 2022, Namyatova et al. 2016). There was an argument that those subfamilies are related (e.g. Schuh and Schwartz 1984, Wolski and Henry 2015), and Wolski and Henry (2015) synonymized Psallopinae with Cylapinae , which was not supported by Namyatova and Cassis (2019b). In the previous molecular-based analyses, representatives of the different Cylapinae groups did not form a monophyletic clade ( Schuh et al. 2009, Namyatova and Cassis 2019 a, Oh et al. 2023). In the study by Schuh et al. (2009), only three species from three tribes were sampled ( Cylapini , Fulviini , and Vanniini ). In the study by Namyatova and Cassis (2019), all tribes were included in the phylogeny; however, in that work only representatives of Psallop s ( Psallopinae ) and Myiomma (Isopmetopinae) were added as outgtoup taxa, and this was not sufficient to test the monophyly of Cylapinae . The phylogenetic study of Oh et al. (2023) provided the most comprehensive analysis of the relationships within Miridae based on the molecular data to date, and they included 11 genera from all Cylapinae tribes, including nominotypical genera. However, Psallops was not included in this analysis. The tribes of Cylapinae in the study by Oh et al. (2023) did not form sister-group relationships with each other. Therefore, in our analysis we expected that some of the taxa placed into Cylapinae might form clades with other mirids.

The results of the present analysis agree with the previous studies and suggest non-monophyly of Cylapinae . In the total-evidence phylogeny, Bothriomirini , Cylapini , and Vanniini form a clade with Bryocorinae , Isometopinae , Mirinae , Orthotylinae , Phylinae , and Deraeocoris ater ( Deraeocorinae ) (PPTE = 98; see node 14). This clade does not appear in other phylogenies. In the morphology-based phylogeny a similar clade is present, but Deraeocoris ater is not included there. In the tree resulting from the Bayesian analysis with 65 taxa, Bothriomirini , Cylapini , and Vanniini form a clade with Mirinae , Orthotylinae , Phylinae , and Bryocorinae without Nesidiocoris sp. However, Psallops , Rhinomiris , Phyllofulvius , Psallofulvius , and the undescribed Fulviini genus from Australia are also included in this clade (PP65 = 90). Those clades do not correspond to the results of Oh et al. (2023).

The position of Psallops remains uncertain. Gorczyca (2000) considered Cylapinae , Isometopinae , and Psallopinae as closely related. Wolski and Henry (2015) reported that the last-instar nymphs of Psallops are similar to those of Fulvius . Additionally, Psallofulvius and Phyllofulvius have the labial segment IV subdivided, similar to Psallops (Namyatova 2022, Namyatova and Cassis 2022). In our phylogeny, Psallops never forms well-supported sister-group relationships with any representatives of Cylapinae .

The position of Isometopinae relative to cylapines is also uncertain. In the morphology-based phylogeny, this subfamily forms sister-group relationships with the clade comprising Bothriomirini , Carvalhoma parvum , Dariella rubrocuneata , Cylapinus minusculus , and Schizopteromiris lordhowensis , although with low support. In the total-evidence phylogeny, Isometopinae form a well-supported clade with Bothriomini, Cylapini , Vanniini , and Eccritotarsus cf. nigrocruciatus (PPTE = 98; see node 11). A similar clade does not appear in the phylogenies based only on the molecular data; however, in most of those analyses Isometopinae form sister-group relationships with Ecrritotarsus cf. nigrocruciatus (see node 10). A close phylogenetic position of Isometopinae and Eccritotarsini has never been proposed before. It could also be a result of insufficient sampling of eccritotarsines, which is a highly diverse group ( Konstantinov et al. 2018).