Brain gangliosides in monotremes, marsupials and placentals: phylogenetic and thermoregulatory aspects

The concentration and composition of brain gangliosides of 17 mammalian species belonging to the subclasses of Prototheria (monotremes), Metatheria (marsupials), and Eutheria (placentals) were investigated. The mean concentration of brain gangliosides ranges from 525 to 610 micrograms NeuAc/g wet wt in monotremes, 445-900 micrograms in marsupials and from 630 to 1130 micrograms in the placentals. In the phylogenetic series of mammals, a decrease in the complexity of brain ganglioside composition becomes obvious: a drastic reduction in the number of individual ganglioside fractions particularly those of the c-pathway of biosynthesis, took place from the level of monotremes to that of the marsupials and placentals. In monotremes, marsupials and "lower" placentals (insectivores) the percentage of alkali-labile gangliosides is relatively low (between traces and 5%), whereas in the higher evolved mammals it amounts to about 20% of all gangliosides. The ratio of the contents of the two major mammalian ganglioside fractions GD1a and GT1b is generally in the range of 1.0 and even higher; in the heterothermic platypus from the monotremes and in hibernators among the placental mammals, however, it is much lower (about 0.8). These data support the hypothesis that the brain ganglioside composition not only depends on the phylogenetic level of nervous organization (cephalization) but is additionally correlated with the state of thermal adaptation.     

OSSIFICATION HETEROCHRONY IN THE THERIAN POSTCRANIAL SKELETON AND THE MARSUPIAL–PLACENTAL DICHOTOMY

Postcranial ossification sequences in 24 therian mammals and three outgroup taxa were obtained using clear staining and computed tomography to test the hypothesis that the marsupial forelimb is developmentally accelerated, and to assess patterns of therian postcranial ossification. Sequence rank variation of individual bones, phylogenetic analysis, and algorithm-based heterochrony optimization using event pairs were employed. Phylogenetic analysis only recovers Marsupialia, Australidelphia, and Eulipotyphla. Little heterochrony is found within marsupials and placentals. However, heterochrony was observed between marsupials and placentals, relating to late ossification in hind limb long bones and early ossification of the anterior axial skeleton. Also, ossification rank position of marsupial forelimb and shoulder girdle elements is more conservative than that of placentals; in placentals the hind limb area is more conservative. The differing ossification patterns in marsupials can be explained with a combination of muscular strain and energy allocation constraints, both resulting from the requirement of active movement of the altricial marsupial neonates toward the teat. Peramelemorphs, which are comparatively passive at birth and include species with relatively derived forelimbs, differ little from other marsupials in ossification sequence. This suggests that ossification heterochrony in marsupials is not directly related to diversity constraints on the marsupial forelimb and shoulder girdle.     

Post-weaning cranial ontogeny in two bandicoots (Mammalia,Peramelomorphia, Peramelidae) and comparison with carnivorous marsupials

The ontogeny of the skull has been studied in several marsupial groups such as didelphids, microbiotheriids, and dasyurids. Here, we describe and compare the post-weaning ontogeny of the skull in two species of bandicoots, Echymipera kalubu (Echymiperinae) and Isoodon macrourus (Peramelinae), analyzing specific allometric trends in both groups, describing common (and specific) patterns, and discussing them on functional and phylogenetic grounds. Growth patterns were analyzed both qualitatively and quantitatively, including bivariate and multivariate analyses of allometry. We also evaluated character transformation and phylogenetic signals of the allometric patterns in several groups of marsupials and some placentals. We identified morphological changes between juvenile and adult stages in both species of peramelids, many related to the development of the trophic apparatus. Notable differences were detected in the patterns of growth, suggesting divergences in ontogenetic trajectories between both species. Both bivariate and multivariate methods indicate that positive allometries in E. kalubu apply to longitudinal dimensions, whereas in I. macrourus, positive allometries are restricted to vertical dimensions of the skull. The comparison of the allometric trends of two bandicoots with previously studied taxa reveals that although peramelids exhibit a particularly short gestation period and divergent morphology compared to other marsupials, their pattern does not show any particular trend. Some allometric trends seem to be highly conserved among the species studied, showing weak phylogenetic signal. Marsupials in general do not show particular patterns of post-weaning skull growth compared with placentals.     

Ossification heterochrony in the therian postcranial skeleton and the marsupial-placental dichotomy.

Postcranial ossification sequences in 24 therian mammals and three outgroup taxa were obtained using clear staining and computed tomography to test the hypothesis that the marsupial forelimb is developmentally accelerated, and to assess patterns of therian postcranial ossification. Sequence rank variation of individual bones, phylogenetic analysis, and algorithm-based heterochrony optimization using event pairs were employed. Phylogenetic analysis only recovers Marsupialia, Australidelphia, and Eulipotyphla. Little heterochrony is found within marsupials and placentals. However, heterochrony was observed between marsupials and placentals, relating to late ossification in hind limb long bones and early ossification of the anterior axial skeleton. Also, ossification rank position of marsupial forelimb and shoulder girdle elements is more conservative than that of placentals; in placentals the hind limb area is more conservative. The differing ossification patterns in marsupials can be explained with a combination of muscular strain and energy allocation constraints, both resulting from the requirement of active movement of the altricial marsupial neonates toward the teat. Peramelemorphs, which are comparatively passive at birth and include species with relatively derived forelimbs, differ little from other marsupials in ossification sequence. This suggests that ossification heterochrony in marsupials is not directly related to diversity constraints on the marsupial forelimb and shoulder girdle.     

The root of the mammalian tree inferred from whole mitochondrial genomes

Morphological and molecular data are currently contradictory over the position of monotremes with respect to marsupial and placental mammals. As part of a re-evaluation of both forms of data we examine complete mitochondrial genomes in more detail. There is a particularly large discrepancy in the frequencies of thymine and cytosine (T-C) between mitochondrial genomes that appears to affect some deep divergences in the mammalian tree. We report that recoding nucleotides to RY-characters, and partitioning maximum-likelihood analyses among subsets of data reduces such biases, and improves the fit of models to the data, respectively. RY-coding also increases the signal on the internal branches relative to external, and thus increases the phylogenetic signal. In contrast to previous analyses of mitochondrial data, our analyses favor Theria (marsupials plus placentals) over Marsupionta (monotremes plus marsupials). However, a short therian stem lineage is inferred, which is at variance with the traditionally deep placement of monotremes on morphological data.     

Profiling phylogenetic informativeness

The resolution of four controversial topics in phylogenetic experimental design hinges upon the informativeness of characters about the historical relationships among taxa. These controversies regard the power of different classes of phylogenetic character, the relative utility of increased taxonomic versus character sampling, the differentiation between lack of phylogenetic signal and a historical rapid radiation, and the design of taxonomically broad phylogenetic studies optimized by taxonomically sparse genome-scale data. Quantification of the informativeness of characters for resolution of phylogenetic hypotheses during specified historical epochs is key to the resolution of these controversies. Here, such a measure of phylogenetic informativeness is formulated. The optimal rate of evolution of a character to resolve a dated four-taxon polytomy is derived. By scaling the asymptotic informativeness of a character evolving at a nonoptimal rate by the derived asymptotic optimum, and by normalizing so that net phylogenetic informativeness is equivalent for all rates when integrated across all of history, an informativeness profile across history is derived. Calculation of the informativeness per base pair allows estimation of the cost-effectiveness of character sampling. Calculation of the informativeness per million years allows comparison across historical radiations of the utility of a gene for the inference of rapid adaptive radiation. The theory is applied to profile the phylogenetic informativeness of the genes BRCA1, RAG1, GHR, and c-myc from a muroid rodent sequence data set. Bounded integrations of the phylogenetic profile of these genes over four epochs comprising the diversifications of the muroid rodents, the mammals, the lobe-limbed vertebrates, and the early metazoans demonstrate the differential power of these genes to resolve the branching order among ancestral lineages. This measure of phylogenetic informativeness yields a new kind of information for evaluation of phylogenetic experiments. It conveys the utility of the addition of characters a phylogenetic study and it provides a basis for deciding whether appropriate phylogenetic power has been applied to a polytomy that is proposed to be a rapid radiation. Moreover, it provides a quantitative measure of the capacity of a gene to resolve soft polytomies.     

Heterochrony and post‐natal growth in mammals – an examination of growth plates in limbs

Mammals display a broad spectrum of limb specializations coupled with different locomotor strategies and habitat occupation. This anatomical diversity reflects different patterns of development and growth, including the timing of epiphyseal growth plate closure in the long bones of the skeleton. We investigated the sequence of union in 15 growth plates in the limbs of about 400 specimens, representing 58 mammalian species: 34 placentals, 23 marsupials and one monotreme. We found a common general pattern of growth plate closure sequence, but one that is universal neither between species nor in higher‐order taxa. Locomotor habitat has no detectable correlation with the growth plate closure sequence, but observed patterns indicate that growth plate closure sequence is determined more strongly through phylogenetic factors. For example, the girdle elements (acetabulum and coracoid process) always ossify first in marsupials, whereas the distal humerus is fused before the girdle elements in some placentals. We also found that heterochronic shifts (changes in timing) in the growth plate closure sequence of marsupials occur with a higher rate than in placentals. This presents a contrast with the more limited variation in timing and morphospace occupation typical for marsupial development. Moreover, unlike placentals, marsupials maintain many epiphyses separated throughout life. However, as complete union of all epiphyseal growth plates is recorded in monotremes, the marsupial condition might represent the derived state.     

Optimizing the widely used nuclear protein‐coding gene primers in beetle phylogenies and their application in the genus Sasajiscymnus Vandenberg (Coleoptera: Coccinellidae)

Advances in genomic biology and the increasing availability of genomic resources allow developing hundreds of nuclear protein‐coding (NPC) markers, which can be used in phylogenetic research. However, for low taxonomic levels, it may be more practical to select a handful of suitable molecular loci for phylogenetic inference. Unfortunately, the presence of degenerate primers of NPC markers can be a major impediment, as the amplification success rate is low and they tend to amplify nontargeted regions. In this study, we optimized five NPC fragments widely used in beetle phylogenetics (i.e., two parts of carbamoyl‐phosphate synthetase: CADXM and CADMC, Topoisomerase, Wingless and Pepck) by reducing the degenerate site of primers and the length of target genes slightly. These five NPC fragments and 6 other molecular loci were amplified to test the monophyly of the coccinellid genus Sasajiscymnus Vandenberg. The analysis of our molecular data set clearly supported the genus Sasajiscymnus may be monophyletic but confirmation with an extended sampling is required. A fossil‐calibrated chronogram was generated by BEAST, indicating an origin of the genus at the end of the Cretaceous (77.87 Myr). Furthermore, a phylogenetic informativeness profile was generated to compare the phylogenetic properties of each gene more explicitly. The results showed that COI provides the strongest phylogenetic signal among all the genes, but Pepck, Topoisomerase, CADXM and CADMC are also relatively informative. Our results provide insight into the evolution of the genus Sasajiscymnus, and also enrich the molecular data resources for further study.     

Evolution of metatherian and eutherian (mammalian) characters: a review based on cladistic methodology

Cladistic methodology is used to test the hypothesis that three major monophyletic groups exist among living mammals–the oviparous monotremes (Prototheria), and the viviparous marsupials (Metatheria) and placentals (Eutheria). Evaluation is made of the polarity (i.e. the direction of change in a primitive-to-derived sequence) of numerous characters which distinguish some or all of these groups, and of the usefulness of these characters in phylogenetic inference. An attempt is made to establish the state of these characters in the common Late Jurassic-Early Cretaceous therian ancestor of marsupials and placentals.
It is concluded that the most basic division of the Mammalia is the dichotomy into the subclasses Prototheria (including Monotremata, Multituberculata, Triconodonta, Docodonta) and Theria (including Metatheria, Eutheria, Pantotheria and Symmetrodonta). Two major groups exist among living viviparous mammals, the Metatheria and Eutheria; in a cladistic framework these are sister-groups. It is demonstrated that there is no special (sister-group) relationship between monotremes and marsupials, and there is no justification for placing them in a group Marsupionta.     

Relationships Among the Families and Orders of Marsupials and the Major Mammalian Lineages Based on Recombination Activating Gene-1

Controversies remain over the relationships among several of the marsupial families and between the three major extant lineages of mammals: Eutheria (placentals), Metatheria (marsupials), and Prototheria (monotremes). Two opposing hypotheses place the marsupials as either sister to the placental mammals (Theria hypothesis) or sister to the monotremes (Palimpsest or Marsupionta hypothesis). A nuclear gene that has proved useful for analyzing phylogenies of vertebrates is the recombination activation gene-1 (RAG1). RAG1 is a highly conserved gene in vertebrates and likely entered the genome by horizontal transfer early in the evolution of jawed vertebrates. Phylogenetic analyses were performed on RAG1 sequences from seven placentals, 28 marsupials, and all three living monotreme species. Phylogenetic analyses of RAG1 sequences support many of the traditional relationships among the marsupials and suggest a relationship between bandicoots (order Peramelina) and the marsupial mole (order Notoryctemorphia), two lineages whose position in the phylogenetic tree has been enigmatic. A sister relationship between South American shrew opossums (order Paucituberculata) and all other living marsupial orders is also suggested by RAG1. The relationship between the three major groups of mammals is consistent with the Theria hypothesis, with the monotremes as the sister group to a clade containing marsupials and placentals.     

The Phylogenetic Informativeness of Nucleotide and Amino Acid Sequences for Reconstructing the Vertebrate Tree

To aid in future efforts to accurately reconstruct the vertebrate tree, a quantitative measure of phylogenetic informativeness was applied to nucleotide and amino acid sequences for a set of 11 genes. We identified orthologues and assembled published fossil-calibrated divergence times between taxa that had been sequenced for each gene. Rates of molecular evolution for each site were estimated to characterize the molecular evolutionary pattern of genes and to calculate the phylogenetic informativeness. The fast-evolving gene albumin yielded the highest informativeness over the period from 60 million years ago to 500 million years ago. In contrast, calmodulin yielded the lowest informativeness, presumably because functional constraint minimized substitutions in the amino acid sequence. The gene c-myc showed an intermediate level of informativeness. The nucleotide sequence of cytochrome b showed extremely high utility for recent epochs, but low utility for times before 100 million years ago. We ranked nine other genes for their utility during the epochs of the divergence of the muroid rodents, early placental mammals, early vertebrates, and early metazoa, yielding results consistent with, but more precise than, previous studies. Interestingly, DNA sequence always exceeded amino acid sequence in informativeness over all time scales, yet support values were at best moderately higher. For epochs not subject to strong phylogenetic conflict due to convergence, we advocate gleaning the additional power of the threefold increase in number of characters that is present for DNA sequences over resorting to the less noisy but less informative amino acid sequences.     

Application of the phylogenetic informativeness method to chloroplast markers: A test case of closely related species in tribe Hydrangeeae (Hydrangeaceae)

In evolutionary biology appropriate marker selection for the reconstruction of solid phylogenetic hypotheses is fundamental. One of the most challenging tasks addresses the appropriate choice of genomic regions in studies of closely related species. Robust phylogenetic frameworks are central to studies dealing with questions ranging from evolutionary and conservation biology, biogeography to plant breeding. Phylogenetic informativeness profiles provide a quantitative measure of the phylogenetic signal in markers and therefore a method for locus prioritization. The present work profiles phylogenetic informativeness of mostly non-coding chloroplast regions in an angiosperm lineage of closely related species: the popular ornamental tribe Hydrangeeae (Hydrangeaceae, Cornales, Asterids). A recent phylogenetic study denoted a case of resolution contrast between the two strongly supported clades within tribe Hydrangeeae. We evaluate the phylogenetic signal of 13 highly variable plastid markers for estimating relationships within and among the currently recognized monophyletic groups of this tribe. A selection of combined loci based on their phylogenetic informativeness retrieved more robust phylogenetic hypotheses than simply combining individual markers performing best with respect to resolution, nodal support and accuracy or those presenting the highest number of parsimony informative characters. We propose the rpl32–ndhF intergenic spacer (IGS), trnV–ndhC IGS, trnL–rpl32 IGS, psbT–petB region and ndhA intron as the best candidates for future phylogenetic studies in Hydrangeeae and potentially in other Asterids. We also contrasted the phylogenetic informativeness of coded indels against substitutions concluding that, despite their low phylogenetic informativeness, coded indels provide additional phylogenetic signal that is nearly free of noise. Phylogenetic relationships obtained from our total combined analyses showed improved resolution and nodal support with respect to recently published results.     

Why are There Fewer Marsupials than Placentals? On the Relevance of Geography and Physiology to Evolutionary Patterns of Mammalian Diversity and Disparity

Placental mammals occupy a larger morphospace and are taxonomically more diverse than marsupials by an order of magnitude, as shown by quantitative and phylogenetic studies of several character complexes and clades. Many have suggested that life history acts as a constraint on the evolution of marsupial morphology. However, the frequent circumvention of constraints suggests that the pattern of morphospace occupation in marsupials is more a reflection of lack of ecological opportunity than one of biases in the production of variants during development. Features of marsupial physiology are a potential source of biases in the evolution of the group; these could be coupled with past macroevolutionary patterns that followed conditions imposed by global temperature changes. This is evident at the K/Pg boundary and at the Eocene/Oligocene boundary. The geographic pattern of taxonomic and morphological diversity in placental clades mirrors that of extant placentals as a whole versus marsupials: placentals of northern origin are more diverse those of southern one and include the clades that are outliers in taxonomic (rodents and bats) and ecomorphological (whales and bats) richness.     

Genome‐wide survey of nuclear protein‐coding markers for beetle phylogenetics and their application in resolving both deep and shallow‐level divergences

Beetles (Coleoptera) are the most diverse and species‐rich insect group, representing an impressive explosive radiation in the evolutionary history of insects, and their evolutionary relationships are often difficult to resolve. The amount of ‘traditional markers’ (e.g. mitochondrial genes and nuclear rDNAs) for beetle phylogenetics is small, and these markers often lack sufficient signals in resolving relationships for such a rapidly radiating lineage. Here, based on the available genome data of beetles and other related insect species, we performed a genome‐wide survey to search nuclear protein‐coding (NPC) genes suitable for research on beetle phylogenetics. As a result, we identified 1470 candidate loci, which provided a valuable data resource to the beetle evolutionary research community for NPC marker development. We randomly chose 180 candidate loci from the database to design primers and successfully developed 95 NPC markers which can be PCR amplified from standard genomic DNA extracts. These new nuclear markers are universally applicable across Coleoptera, with an average amplification success rate of 90%. To test the phylogenetic utility, we used them to investigate the backbone phylogeny of Coleoptera (18 families sampled) and the family Coccinellidae (39 species sampled). Both phylogenies are well resolved (average bootstrap support >95%), showing that our markers can be used to address phylogenetic questions of various evolutionary depth (from species level to family level). In general, the newly developed nuclear markers are much easier to use and more phylogenetically informative than the ‘traditional markers’, and show great potential to expedite resolution of many parts in the Beetle Tree of Life.     

Rapid development of multiple nuclear loci for phylogenetic analysis using genomic resources: an example from squamate reptiles

Recently, as genome-scale data have become available for more organisms, the development of phylogenetic markers from nuclear protein-coding loci (NPCL) has become more tractable. However, new methods are needed to efficiently sort the large number of genes from genomic databases into more limited sets appropriate for particular phylogenetic questions, while avoiding introns and paralogs. Here we describe a general methodology for identifying candidate single-copy NPCL from genomic databases. Our method uses information from reference genomes to identify genes with relatively large continuous protein-coding regions (i.e., 700bp). BLAST comparisons are used to help avoid genes with paralogous copies or close relatives (i.e., gene families) that might confound phylogenetic analyses. Exon boundary information is used to identify appropriately spaced potential priming sites. Using this method, we have developed over 25 novel NPCL, which span a variety of desirable evolutionary rates for phylogenetic analyses. Although targeted for higher-level phylogenetics of squamate reptiles, many of these loci appear to be useful across and within other vertebrate clades (e.g., amphibians), and some are relatively rapidly evolving and may be useful for closely-related species (e.g., within genera). This general method can be used whenever large-scale genomic data are available for an appropriate reference species (not necessarily within the focal clade). The method is also well suited for the development of intron regions for lower-level phylogenetic and phylogeographic studies. We provide an online database of alignments and suggested primers for approximately 85 NPCL that should be useful across vertebrates.     

Parasite histories and novel phylogenetic tools: alternative approaches to inferring parasite evolution from molecular markers

Parasitological research is often contingent on the knowledge of the phylogeny/genealogy of the studied group. Although molecular phylogenetics has proved to be a powerful tool in such investigations, its application in the traditional fashion, based on a tree inference from the primary nucleotide sequences may, in many cases, be insufficient or even improper. These limitations are due to a number of factors, such as a scarcity/ambiguity of phylogenetic information in the sequences, an intricacy of gene relationships at low phylogenetic levels, or a lack of criteria when deciding among several competing coevolutionary scenarios. With respect to the importance of a precise and reliable phylogenetic background in many biological studies, attempts are being made to extend molecular phylogenetics with a variety of new data sources and methodologies. In this review, selected approaches potentially applicable to parasitological research are presented and their advantages as well as drawbacks are discussed. These issues include the usage of idiosyncratic markers (unique features with presumably low probability of homoplasy), such as insertion of mobile elements, gene rearrangements and secondary structure features; the problem of ancestral polymorphism and reticulate relationships at low phylogenetic levels; and the utility of a molecular clock to facilitate discrimination among alternative scenarios in host-parasite coevolution.     

Energetic trade-offs between brain size and offspring production: Marsupials confirm a general mammalian pattern

Recently, Weisbecker and Goswami presented the first comprehensive comparative analysis of brain size, metabolic rate, and development periods in marsupial mammals. In this paper, a strictly energetic perspective is applied to identify general mammalian correlates of brain size evolution. In both marsupials and placentals, the duration or intensity of maternal investment is a key correlate of relative brain size, but here I show that allomaternal energy subsidies may also play a role. In marsupials, an energetic constraint on brain size in adults is only revealed if we consider both metabolic and reproductive rates simultaneously, because a strong trade-off between encephalization and offspring production masks the positive correlation between basal metabolic rate and brain size in a bivariate comparison. In conclusion, starting from an energetic perspective is warranted to elucidate relations between ecology, social systems, life history, and brain size in all mammals.     

Phylogeny, diet, and cranial integration in australodelphian marsupials

Studies of morphological integration provide valuable information on the correlated evolution of traits and its relationship to long-term patterns of morphological evolution. Thus far, studies of morphological integration in mammals have focused on placentals and have demonstrated that similarity in integration is broadly correlated with phylogenetic distance and dietary similarity. Detailed studies have also demonstrated a significant correlation between developmental relationships among structures and adult morphological integration. However, these studies have not yet been applied to marsupial taxa, which differ greatly from placentals in reproductive strategy and cranial development and could provide the diversity necessary to assess the relationships among phylogeny, ecology, development, and cranial integration. This study presents analyses of morphological integration in 20 species of australodelphian marsupials, and shows that phylogeny is significantly correlated with similarity of morphological integration in most clades. Size-related correlations have a significant affect on results, particularly in Peramelia, which shows a striking decrease in similarity of integration among species when size is removed. Diet is not significantly correlated with similarity of integration in any marsupial clade. These results show that marsupials differ markedly from placental mammals in the relationships of cranial integration, phylogeny, and diet, which may be related to the accelerated development of the masticatory apparatus in marsupials.     

Rearrangements of mitochondrial transfer RNA genes in marsupials

Summary The nucleotide sequences of the mitochondrial origin of light-strand replication and the five tRNA genes surrounding it were determined for three marsupials. The region was found to be rearranged, leaving only the tRNA^Tyr gene at the same position as in placental mammals andXenopus. Distribution of the same rearranged genotype among two marsupial families indicates that the events causing the rearrangements took place in an early marsupial ancestor. The putative mitochondrial light-strand origin of replication in marsupials contains a hairpin structure similar to other vertebrate origins and, in addition, extensive flanking sequences that are not found in other vertebrates. Sequence comparisons among the marsupials as well as placentals indicate that the tRNA^Tyr gene has been evolving under more constraints than the other tRNA genes.Deceased July 21, 1991     

Female genitalia are moderately informative for phylogenetic inference and not concerted with male genitalia in Saprininae beetles (Coleoptera: Histeridae)

Our study – the first of its kind within Histeridae (Coleoptera) – deals with the female genitalia in the subfamily Saprininae, with respect to their variation and utility for phylogenetic reconstruction. Morphology of female genitalia (chiefly characters of the spermatheca, and variation of the gonocoxites, articulating sclerites and gonostyli) is herein described and depicted. We perform parsimony‐based morphological phylogenetic analyses of Saprininae using combined datasets that comprise somatic, male and female genitalia characters. We assess phylogenetic utility of female genital characters and test for their correlation with male genital characters. We found that female genitalia are generally moderately informative for phylogenetic reconstruction. The somatic and male genitalia characters (on average) possess higher phylogenetic signal; female genitalia provide better support and diagnoses for particular clades (emphasizing their importance for systematics), in which the evolution of female genitalia can be linked to environmental factors imposed by the mode of life. Regardless of the degree of informativeness, structures of female genitalia represent an additional interesting and important source of information for systematics and taxonomy. We did not find any evidence of correlated evolution between male and female genitalia.