Morphological Diversity of the Skeletal Structures and Problems of Classification of Fleas (Siphonaptera). Part 6

The structure of 76 skeletal elements of adult fleas was analyzed, and the distribution of 114 characters with 446 character states over the body tagmata, segments, and morphofunctional complexes was investigated. Among them, 40% of the characters (40) and their states (163) describe the diversity of the structures of the frontal complex (including those of the head and prothorax), which is related to the specific features of flea parasitism. A large part of the characters (18) and their states (83) describe the structures of the nototrochanteral complex of the meso- and metathorax responsible for jumping. The total number of all types of homoplasies (258 states) is almost 1.8 times as great as the number of the states (145) that may be regarded as synapomorphies. The ancestral states (43) comprise a smaller portion of the total number. The proportion of the synapomorphic and homoplastic character states varies between the morphofunctional complexes.     

Classification of the flea families (Siphonaptera): II. Family Hystrichopsyllidae (part 2)

Morphology of the flea family Hystrichopsyllidae is considered. The subfamilies Stenoponiinae, Neopsyllinae, Doratopsyllinae, and Ctenophthalminae are distinguished. In all, 148 states of the characters of the head, thorax, modified abdominal segments, and aedeagus have been analyzed within the family Hystrichopsyllidae and the whole order Siphonaptera as well.     

Classification of flea families (Siphonaptera): I. Family Hystrichopsyllidae (first part)

A contribution is made to the previously elaborated classification of the order Siphonaptera (Medvedev, 1994, 1998). Host-parasite associations, geographical distribution, and morphology of the family Hystrichopsyllidae (sensu Hopkins and Rothschild, 1962, 1966) in comparison with other flea families are analyzed together with a position of the family within the infraorder Hystrichopsyllomorpha. The presence of two spermathecae, frequently used as a taxonomic character, is a character insufficient for the basic phylogenetic reconstructions, e.g., establishment of close relationship between the families Coptopsyllidae and Macropsyllidae or the tribes Ctenopariini and Hystrichopsyllini, because this character is a plesiomorphy of the order Siphonaptera. The subfamily Hystrichopsyllinae (sensu Hopkins and Rothschild, 1962) is characterized by a large number of morphological features which can be considered as plesiomorphic characters of the family Hystrichopsyllidae as a whole. The subfamily Hystrichopsyllinae should be restricted to the tribes Ctenopariini and Hystrichopsyllini. The family Macropsyllidae possesses a unique structure of the ctenidia and some other structures. It should be treated as a group closely related to Hystrichopsyllidae. The family Coptopsyllidae demonstrates another trend in the evolution of the head, thorax, and abdomen.     

Morphological diversity of the skeletal structures of fleas (Siphonaptera). Part 4: The general characteristic and features of the abdomen

Characters of 25 abdominal structures were analyzed in the fleas of 96 genera representing over 90% of the world fauna. It was shown that different flea taxa could be described based on 16 universal and 12 specific characters, whose 108 states reflect the entire known diversity of the flea abdominal morphology. Of them, 16 characters with 39 states are formulated based on universal terms. Five universal characters with 13 states describe the proportions of various structures, and also the proportions and shapes of their sclerites; 17 specific characters with 69 states describe the structure of the skeletal elements and the patterns of their junctions. Judging by the number of characters (14) and their states (69), the most evolutionarily flexible structures in fleas are the inner sclerites and anchoring structures of the aedeagus, sternite IX in males, and also the spermatheca and tergite I in females. The character states reflecting the possible phylogenetic closeness of taxa comprise 39%, while 61% of the abdominal character states are homoplasies.     

Taxonomic composition and zoogeographic characteristics of the flea fauna (Siphonaptera) of Russia

255 species and 59 subspecies of fleas from 55 genera of 7 families are known from Russia, which is 30% of the Palaearctic fauna. Additionally, over 187 species of 47 genera from 7 families are known from the neighboring territories of Central and Southern Europe, Transcaucasia, Kazakhstan, Middle Asia, Mongolia, Northeast China, and Japan. 13 species of 12 genera are known only from Russia. Noteworthy is the low percent of endemic species (not more than 4%) and genera (one genus) in the Russian fauna. The principal centers of taxonomic diversity in the Palaearctic, including many endemic species and genera, lie in the Eastern Asian, Central Asian, and Turano-Iranian Subregions, outside Russia and the Euro-Siberian Subregion. The bulk of the Russian fauna is formed by the species and genera of the three largest flea families: Hystrichopsyllidae, Ceratophyllidae, and Leptopsyllidae. The family Ceratophyllidae has the greatest number of genera in the Russian fauna, and Hystrichopsyllidae, the greatest number of species. Western (Western and Western-Central Palaearctic; 84 species from 41 genera of 7 families) and Eastern (Central-Eastern and Eastern Palaearctic; 78 species from 42 genera of 6 families) species are nearly equally represented in the Russian fauna.     

Morphological diversity of the skeletal structures of fleas (Siphonaptera). Part 3: The general characteristics and features of thoracic setation

The paper continues the series of publications (Medvedev, 2015, 2016) devoted to the analysis of the structural features of fleas. In this part, the structural features of the thoracic setation are analyzed for the first time. Six characters with 53 states were distinguished in the chaetome of the pronotum, mesothorax, and metathorax. The analysis reveals some cases of the formation of externally similar states due to reduction or, by contrast, strengthening of the chaetome in some genera belonging to different superfamilies, in relation to the specific traits of parasitism. In spite of high variation in the number and arrangement of thoracic setae, some character states can be used as markers of flea taxa of the family and superfamily rank.     

Peculiarities of thoracic and abdominal combs of fleas (Siphonaptera)

The structure of pseudosetae, spinelets, and spines of combs (ctenidia) was studied by means of light and SE microscopy in 80% of genera and subgenera of the World fauna. It is found out that peculiarities of ctenidiae in the prothorax and in tergites of the abdomen are characteristics of families and infraorders of fleas. Some characters of ctenidiae found in certain flea genera are reductions and apparently caused by habitation in some extremal conditions. An absence of ctenidiae in the unfraorder Pulicomorpha is compensated by more developed posterior margin of prothorax and general abbreviation of all thoracal segments. Reasons of ctenidiae absence, which is observed in certain genera of the infraorders Ceratophyllomorpha, Pygiopsyllomorpha and Hystricopsillomorpha associated with the same hosts, is not clear. It is confirmed, that distance between ctenidiae in different flea species associated with the same species host species, however it is recovered, that this distance correlates with the diameter of most thin hair of host. In some flea species the distance between ctenidia spices in females is larger, than in males. It is found, that sexual dimorphism by this character may not be expressed in certain species of closely related species group of fleas. It is suggested that ctenidiae were present even in the common ancestor of fleas. The hypothesis on origin of spines and pseudosetae from setae of the posterior walls of toracal and abdominal segments in the common ancestor of fleas is proposed.     

The Palaearctic centers of taxonomic diversity of fleas (Siphonaptera)

The Palaearctic flea fauna includes 921 species and 479 subspecies from 96 genera of 10 families. Of them, 858 species (94%) from 43 genera are endemic to the Palaearctic; they comprise 40% of the Palaearctic Hystrichopsyllidae, 24% of Ceratophyllidae, and 20% of Leptopsyllidae. Ranges of 581 species (63% of the Palaearctic fauna) are situated within one province or subregion of the Palaearctic. Species with ranges including a part of Asia (592) comprise 87% of the total fauna; 72% of the species (517) are endemic to the Palaearctic. The largest centers of taxonomic diversity of Palaearctic fleas are situated in the East Asian, Central Asian, and Turano-Iranian Subregions: 320 species of fleas (214 of them endemic) from 59 genera (8 endemic) are known from the East Asian Subregion; 270 species (over 120 endemic) from 54 genera (5 endemic) are distributed in the Central Asian Subregion. The Turano-Iranian fauna comprises 213 species (103 endemic) from 47 genera (3 endemic); about 160 species occur in the Turanian Subprovince closest to the Russian borders, one-third of them (52 species, or 33%) are endemic; 69 species more are endemic to the entire Asian part of the Palaearctic. Extra-Asian and extra-Siberian ranges are known in 190 flea species. In the western Palaearctic, 76 species are endemic to the European Province, and 57 species, to the Mediterranean Province; 36 species have Euro-Mediterranean distribution. The fauna of the Saharo-Arabian Subregion comprises 30 species (12 endemic), 6 species have ranges of the Mediterranean-Saharo-Arabian type. Scenarios of the origin of the Siphonaptera at the Triassic-Jurassic boundary are hypothesized. Formation of the Palaearctic flea fauna was mostly supported by the Asian-Indo-Malayan and East Asian-Western American palaeofaunal centers of taxonomic diversity. The long history of faunal exchange between the east Palaearctic and the west Nearctic is manifested by the distribution of the parasites of rodents and insectivores, fleas of the genera Stenoponia, Rhadinopsylla, Nearctopsylla, and Catallagia, belonging to several subfamilies of the Hystrichopsyllidae, as well as members of a number of other flea families. A great number of endemic species in the genera Palaeopsylla and Ctenophthalmus (Hystrichopsyllidae), both in the European and Asian parts of the Palaearctic, can be explained by the junction of the European and Asian continental platforms in the late Cretaceous and their subsequent isolation during the Paleocene. A considerable contribution to the flea fauna in the Russian territory was made by the East Asian-Nearctic center of taxonomic diversity, with a smaller role of the European palaeofauna. Immigration of species of the family Pulicidae from the Afrotropical Region is restricted to the southern territories of Russia.     

Classification of the flea families (Siphonaptera): II. Family Hystrichopsyllidae (Part 3)

Morphological characters and their diversity in the Afrotropical subfamilies Dinopsyllinae and Listropsyllinae, and the Holarctic subfamily Anomiopsyllinae are evaluated. Three centers had the major significance in the formation of the family Hystrichopsyllidae: the South American (extra-Caribbean), Afro-European, and North American and Asian ones. One more center may have been located in Australia but its fauna has become largely extinct or remains unknown. The origin of a number of tribes of the subfamilies Hystrichopsyllinae and Doratopsyllinae is associated with the South American center; the origin of subgenera of the subfamily Ctenophthalminae as well as the subfamilies Listropsyllinae and Dinopsyllinae, with the Afro-European center; and the origin of the subfamilies Neopsyllinae, Rhadinopsyllinae, Anomiopsyllinae, Stenoponiinae, and Liuopsyllinae, with the North American and Asian center. Distribution of the subfamilies Doratopsyllinae and Hystrichopsyllinae sheds light on the initial stages of formation of the family Hystrichopsyllidae.     

Floral morphometrics and the evolution of sexual dimorphism in Lycium (Solanaceae)

Plants of Lycium californicum, L. exsertum, and L. fremontii produce flowers that are either male-sterile (female) or hermaphroditic, and populations are morphologically gynodioecious. As is commonly found in gynodioecious species, flowers on female plants are smaller than those on hermaphrodites for a number of floral traits. Floral size dimorphism has often been hypothesized to be the result of either a reduction in female flower size that allows reallocation to greater fruit and seed production, or an increase in hermaphroditic flower size due to the increased importance of pollinator attraction and pollen export for hermaphroditic flowers. We provide a test of these two alternatives by measuring 11 floral characters in eight species of Lycium and using a phylogeny to reconstruct the floral size shifts associated with the evolution of gender dimorphism. Our analyses suggest that female flowers are reduced in size relative to the ancestral condition, whereas flowers on hermaphrodites have changed only slightly in size. Female and hermaphroditic flowers have also diverged both from one another and from ancestral cosexual species in several shape characteristics. We expected sexual dimorphism to be similar among the three dimorphic taxa, as gender dimorphism evolved only a single time in the ancestor of the American dimorphic lineage. While the floral sexual dimorphism is broadly similar among the three dimorphic species, there are some species-specific differences. For example, L. exsertum has the greatest floral size dimorphism, whereas L. fremontii had the greatest size-independent dimorphism in pistil characters. To determine the degree to which phylogenetic uncertainty affected reconstruction of ancestral character states, we performed a sensitivity analysis by reconstructing ancestral character states on alternative topologies. We argue that investigations such as this one, that examine floral evolution from an explicitly phylogenetic perspective, provide new insights into the study of the evolution of floral sexual dimorphism.     

Morphological Diversity of Fleas’ Structures (Siphonaptera). Part 5: Features of Thoracic Combs and Legs

37 states of 9 characters of the thoracic combs, coxae, and the 5th hind tarsomere of fleas are analyzed. Some of these character states mark groups of families in the infraorders Pulicomorpha, Hystrichopsyllomorpha, Pygiopsyllomorpha and Ceratophyllomorpha.     

Morphological diversity of the skeletal structures of fleas (Siphonaptera). Part 2: The general characteristic and features of the thorax

Analysis of a considerable amount of data on the anatomy of 27 structures of the thorax in 96 genera of fleas (over 90% of the genera in the world fauna) shows that different flea taxa can be described based on 48 universal and specific characters, whose 203 states reflect the entire known diversity of the flea morphology. Of them, 26 characters with 96 states can be formulated based on universal terms; 22 universal characters with 88 states describe the proportions of the segments and their parts, and also proportions and shapes of their sclerites; 23 specific characters with 107 states describe the structure of the thoracic sclerites and ridges as well as the patterns of their junctions. Judging by the number of characters and their states, the most evolutionarily flexible structures in fleas are the mesosternite and its apodeme together with the upper part of the mesopleural rod. Homoplasies at various levels comprise less than half (40%) of all the character states in the thorax structure. The character states reflecting the phylogenetic closeness of taxa make up about 15%.     

Classification of the flea families (Siphonaptera): I. Family Hystrichopsyllidae (Part 5)

Based on analysis of homologous character states and considering the molecular-biological data (Whiting et al., 2008), phylogenetic relationships of the tribes and subfamilies of the family Hystrichopsyllidae are discussed. In some cases, homologous states of the skeleton characters mark the clades revealed by the moleculargenetic analysis, but are shared by taxa from other clades. In contrast to the molecular-genetic data, morphological characters indicate the phylogenetic integrity of the family Hystrichopsyllidae. Morphological characters depict the subfamily Anomiopsyllinae as a monophyletic taxon (having synapomorphic states of the metaphragma, metasternite, and the mesosternal apodeme) closest to the subfamilies Neopsyllinae and Rhadinopsyllinae. The subfamilies Neopsyllinae, Rhadinopsyllinae, and Stenoponiinae have a non-thickened metasternite; the former two subfamilies also have in common a similar structure of articulation of the digitoid with the clasper, type of the metaphragma modification, and the presence of the sclerotized central sclerite. Homologous modifications of the metaphragma are also present in fleas of the subfamily Stenoponiinae. Close to this group are the subfamily Hystrichopsyllinae whose representatives also possess non-thickened metasternal apodemes, and the subfamily Listropsyllinae with its frontal sclerotized tubercle being a specialized modification of the frontal sclerotized fold. A specific feature shared by fleas of the subfamilies Hystrichopsyllinae and Listropsyllinae is the presence of the metasternal furca with high sharp processes and a high medial ridge. The closeness of these taxa is supported by the results of molecular-genetic analysis. The subfamilies Doratopsyllinae and Ctenophthalminae (tribes Ctenophthalmini and Carterettini) are united by the type of the attachment of the mesopleural rod to the special ridge at the upper margin of the mesopleuron. According to the molecular-genetic data, the tribe Neotyphloceratini is related to these subfamilies, even though its members have no ridge on the mesopleuron. The similarity in the structure of the furca (the presence of high dorsal processes with rounded apices and a high median ridge) and in the length ratio of the fulcrum lobes relates the subfamilies Ctenophthalminae and Dinopsyllinae.     

Understanding Phenotypical Character Evolution in Parmelioid Lichenized Fungi (Parmeliaceae,Ascomycota)

Parmelioid lichens form a species-rich group of predominantly foliose and fruticose lichenized fungi encompassing a broad range of morphological and chemical diversity. Using a multilocus approach, we reconstructed a phylogeny including 323 OTUs of parmelioid lichens and employed ancestral character reconstruction methods to understand the phenotypical evolution within this speciose group of lichen-forming fungi. Specifically, we were interested in the evolution of growth form, epicortex structure, and cortical chemistry. Since previous studies have shown that results may differ depending on the reconstruction method used, here we employed both maximum-parsimony and maximum-likelihood approaches to reconstruct ancestral character states. We have also implemented binary and multistate coding of characters and performed parallel analyses with both coding types to assess for potential coding-based biases. We reconstructed the ancestral states for nine well-supported major clades in the parmelioid group, two higher-level sister groups and the ancestral character state for all parmelioid lichens. We found that different methods for coding phenotypical characters and different ancestral character state reconstruction methods mostly resulted in identical reconstructions but yield conflicting inferences of ancestral states, in some cases. However, we found support for the ancestor of parmelioid lichens having been a foliose lichen with a non-pored epicortex and pseudocyphellae. Our data suggest that some traits exhibit patterns of evolution consistent with adaptive radiation.     

A molecular phylogeny of fleas (Insecta: Siphonaptera): origins and host associations

Siphonaptera (fleas) is a highly specialized order of holometabolous insects comprising ～2500 species placed in 16 families. Despite a long history of extensive work on flea classification and biology, phylogenetic relationships among fleas are virtually unknown. We present the first formal analysis of flea relationships based on a molecular matrix of four loci (18S ribosomal DNA, 28S ribosomal DNA, Cytochrome Oxidase II, and Elongation Factor 1‐alpha) for 128 flea taxa from around the world representing 16 families, 25 subfamilies, 26 tribes, and 83 flea genera with eight outgroups. Trees were reconstructed using direct optimization and maximum likelihood techniques. Our analysis supports Tungidae as the most basal flea lineage, sister group to the remainder of the extant fleas. Pygiopsyllomorpha is monophyletic, as are the constituent families Lycopsyllidae, Pygiopsyllidae, and Stivaliidae, with a sister group relationship between the latter two families. Macropsyllidae is resolved as sister group to Coptopsyllidae with moderate nodal support. Stephanociricidae is monophyletic, as are the two constituent subfamilies Stephanocircinae and Craneopsyllinae. Vermipsyllidae is placed as sister group to Jordanopsylla. Rhopalopsyllidae is monophyletic as are the two constituent subfamilies Rhopalopsyllinae and Parapsyllinae. Hystrichopsyllidae is paraphyletic with Hystrichopsyllini placed as sister to some species of Anomiopsyllini and Ctenopariini placed as sister to Carterettini. Ctenophthalmidae is grossly paraphyletic with the family broken into seven lineages dispersed on the tree. Most notably, Anomiopsyllini is paraphyletic. Pulicidae and Chimaeropsyllidae are both monophyletic and these families are sister groups. Ceratophyllomorpha is monophyletic and includes Ischnopsyllidae, Ceratophyllidae, and Leptopsyllidae. Leptopsyllidae is paraphyletic as are its constituent subfamilies Amphipsyllinae and Leptopsyllinae and the tribes Amphipsyllini and Leptopsyllini. Ischnopsyllidae is monophyletic. Ceratophyllidae is monophyletic, with a monophyletic Dactypsyllinae nested within Ceratophyllinae, rendering the latter group paraphyletic. Mapping of general host associations on our topology reveals an early association with mammals with four independent shifts to birds. © The Willi Hennig Society 2008.     

Evolutionary history of vegetative reproduction in Porpidia s.L. (Lichen-forming ascomycota)

The evolutionary history of gains and losses of vegetative reproductive propagules (soredia) in Porpidia s.l., a group of lichen-forming ascomycetes, was clarified using Bayesian Markov chain Monte Carlo (MCMC) approaches to monophyly tests and a combined MCMC and maximum likelihood approach to ancestral character state reconstructions. The MCMC framework provided confidence estimates for the reconstructions of relationships and ancestral character states, which formed the basis for tests of evolutionary hypotheses. Monophyly tests rejected all hypotheses that predicted any clustering of reproductive modes in extant taxa. In addition, a nearest-neighbor statistic could not reject the hypothesis that the vegetative reproductive mode is randomly distributed throughout the group. These results show that transitions between presence and absence of the vegetative reproductive mode within Porpidia s.l. occurred several times and independently of each other. Likelihood reconstructions of ancestral character states at selected nodes suggest that--contrary to previous thought--the ancestor to Porpidia s.l. already possessed the vegetative reproductive mode. Furthermore, transition rates are reconstructed asymmetrically with the vegetative reproductive mode being gained at a much lower rate than it is lost. A cautious note has to be added, because a simulation study showed that the ancestral character state reconstructions were highly dependent on taxon sampling. However, our central conclusions, particularly the higher rate of change from vegetative reproductive mode present to absent than vice versa within Porpidia s.l., were found to be broadly independent of taxon sampling.     

Mapping uncertainty and phylogenetic uncertainty in ancestral character state reconstruction: an example in the moss genus Brachytheciastrum

The evolution of species traits along a phylogeny can be examined through an increasing number of possible, but not necessarily complementary, approaches. In this paper, we assess whether deriving ancestral states of discrete morphological characters from a model whose parameters are (i) optimized by ML on a most likely tree; (II) optimized by ML onto each of a Bayesian sample of trees; and (III) sampled by a MCMC visiting the space of a Bayesian sample of trees affects the reconstruction of ancestral states in the moss genus Brachytheciastrum. In the first two methods, the choice of a single- or two-rate model and of a genetic distance (wherein branch lengths are used to determine the probabilities of change) or speciational (wherein changes are only driven by speciation events) model based upon a likelihood-ratio test strongly depended on the sampled trees. Despite these differences in model selection, reconstructions of ancestral character states were strongly correlated to each others across nodes, often at r > 0.9, for all the characters. The Bayesian approach of ancestral character state reconstruction offers, however, a series of advantages over the single-tree approach or the ML model optimization on a Bayesian sample of trees because it does not involve restricting model parameters prior to reconstructing ancestral states, but rather allows a range of model parameters and ancestral character states to be sampled according to their posterior probabilities. From the distribution of the latter, conclusions on trait evolution can be made in a more satisfactorily way than when a substantial part of the uncertainty of the results is obscured by the focus on a single set of model parameters and associated ancestral states. The reconstructions of ancestral character states in Brachytheciastrum reveal rampant parallel morphological evolution. Most species previously described based on phenetic grounds are thus resolved of polyphyletic origin. Species polyphylly has been increasingly reported among mosses, raising severe reservations regarding current species definition.     

Protoanthropoidea (Primates, Simiiformes): A New Primate Higher Taxon and a Solution to the Rooneyia Problem

As a derivative of the hypothesis that anthropoids evolved from omomyid-like primates, the enigmatic North American fossil Rooneyia viejaensis, from the latest Eocene of Texas, is placed in a new higher taxon, Protoanthropoidea, which is proposed as the sister-group of Anthropoidea. Rooneyia and anthropoids share synapomorphically a pattern of character states relating to the unique orbital morphology of higher primates, including; highly convergent and frontated orbits roofed above by an extended frontal bone; funnel-shaped orbital fossae; orbital apices that are recessed beneath the forebrain; a deep, large lateral process of the frontal bone (upper portion of the postorbital bar) that may presage closure of the orbit by an enlarged ascending process of the zygomatic. If the sister-group of anthropoids occupied North America as part of a Laurasian geographic distribution during the Paleogene, as some primate genera did, ancestral anthropoids may likewise have occurred across Laurasia, prestaging them to enter Africa and Central/South America in two independent episodes of dispersal—without having the ancestral platyrrhines crossing the daunting Atlantic Ocean.     

Aedeagal Divergence in Sympatric Populations of Two Sibling Species of Cactophilic Drosophila (Diptera: Drosophilidae): Evidence of Character Displacement?

Aedeagal morphology of two sibling cactophilic species, Drosophila buzzatii Patterson & Wheeler and Drosophila koepferae Fontdevila & Wasserman, was analyzed in nine allopatric and three sympatric locations throughout South America. Morphological differences were detected for both aedeagus size and shape between sympatric and allopatric populations of D. buzzatii, despite the significant variability within both groups. Populations of D. buzzatii sympatric with D. koepferae displayed smaller aedeagus than the allopatric ones as well as more differentiated aedeagus shape. The shape differences were non-allometric and mainly consisted in a change of curvature of the dorsal margin of the aedeagus being more pronounced in males from populations sympatric with D. koepferae. It is concluded that aedeagal morphology presented some degree of character displacement in both size and shape in populations of D. buzzatii in sympatry with D. koepferae. These results might suggest the existence of mechanisms of interspecific recognition and hybridization prevention between these species that include the morphology of the male genitalia.