The morphological evolution of the Adephaga (Coleoptera)

Abstract

The evolution of the coleopteran suborder Adephaga is discussed based on a robust phylogenetic background. Analyses of morphological characters yield results nearly identical to recent molecular phylogenies, with the highly specialized Gyrinidae placed as sister to the remaining families, which form two large, reciprocally monophyletic subunits, the aquatic Haliplidae + Dytiscoidea (Meruidae, Noteridae, Aspidytidae, Amphizoidae, Hygrobiidae, Dytiscidae) on one hand, and the terrestrial Geadephaga (Trachypachidae + Carabidae) on the other. The ancestral habitat of Adephaga, either terrestrial or aquatic, remains ambiguous. The former option would imply two or three independent invasions of aquatic habitats, with very different structural adaptations in larvae of Gyrinidae, Haliplidae and Dytiscoidea.

Data curation and modeling of compositional heterogeneity in insect phylogenomics: A case study of the phylogeny of Dytiscoidea (Coleoptera: Adephaga)

“…Both adult Dytiscidae and Hygrobiidae also share the presence of prothoracic glands, among other characters (Forsyth, 1970;Beutel, 1986;Beutel, 1988). A clade comprising the two families was recently recovered by a maximum parsimony analysis of morphological data (Beutel et al, 2019). This same analysis also recovered Aspidytidae as a sister to Amphizoidae, in congruence with our CAT-GTR trees.…”

“…Tackling potential sources of systematic error strengthens support for a relationship between Hygrobiidae and Dytiscidae. Integrating various previous studies of the systematic position of the small family Meruidae (Balke et al, 2008;Baca et al, 2017;Beutel et al, 2013Beutel et al, , 2019Toussaint et al, 2015;McKenna et al, 2015), we propose an integrated phylogenetic framework for the six extant families of Dytiscoidea: (Meruidae + Noteridae) + ((Aspidytidae + Amphizoidae) + (Dytiscidae + Hygrobiidae)) (Fig. 4).…”

“…This same analysis also recovered Aspidytidae as a sister to Amphizoidae, in congruence with our CAT-GTR trees. It should be noted however that some deeper nodes in Beutel et al (2019) did not receive high bootstrap support values, which is a common problem in morphological phylogenies (Fig. S7).…”

“…While the relationship received full support when the recoded datasets were analyzed with CAT-GTR (BPP = 1), we view this relationship as highly unlikely. It was suggested by Vasilikopoulos et al (2019) with uncertainty over the placement of Hygrobiidae but was never recovered by any other formal phylogenetic analysis specifically addressing the phylogeny of Dytiscoidea (Ribera et al, 2002a;Balke et al, 2005Balke et al, , 2008Beutel et al, 2006Beutel et al, , 2013Beutel et al, , 2019Toussaint et al, 2015;Baca et al, 2017;López-López and Vogler, 2017;Gustafson et al, 2019) and is incongruent with morphological evidence discussed below. While in theory Dayhoff-6 recoding should alleviate the effects of compositional heterogeneity, recoding also reduces genuine phylogenetic signal.…”

The enduring value of reciprocal illumination in the era of insect phylogenomics: a response to Cai et al. (2020)

“…having spine‐like invaginations separating them in Dytiscidae). Subsequent cladistic analyses coding the prothoracic defence gland as a simple binary present‐or‐absent character have recovered it either as the only unambiguous synapomorphy uniting Hygrobiidae + Dytiscidae (Beutel & Haas, 1996), or in combination with the larval trochanteral annulus, position of the larval cerebrum (Beutel et al ., 2006; Beutel et al ., 2020) and most recently with the elongate larval antennomere 1 (Beutel et al ., 2020). However, Baehr's (1979) detailed cladistic study of the prothoracic musculature of Adephaga and phylogenetic analyses utilizing molecular data from multiple genes other than the primary use of mitochondrial genes (Table 1), have failed to provide support for the synapomorphy of the prothoracic gland (de Pinna, 1991), instead corroborating the likely convergent evolutionary origins of these structures.…”