Phylogeny of Neotropical Monkeys: The Interplay of Morphological, Molecular, and Parasitological Data

Separate independent hypotheses of the phylogenetic relationships among the Platyrrhini monkeys have been produced in a recent past, either based upon morphological or molecular data, but the results are generally conflicting and the phylogeny of the group still is debated. The high host specificity observed among primates and their oxyurid parasites allows to consider the result of a morphologically based cladistic analysis of the pinworms of the Platyrrhini as an estimate of the phylogeny of these monkeys. Using the matrix representation method this “parasite-tree” is combined, using parsimony analysis, with several conflicting molecular or morphological hypothesis of the phylogeny of the host group. The results are discussed with respect to previously published classification, or composite computations of the phylogeny, of the Neotropical monkeys. Comparison of different hypothesis makes apparent several stable groups: (i) the Callithrichidae +Saimiri,(ii) the Atelidae/Alouattidae, (iii) the Pitheciidae, and (iv) the Alouattidae/Atelidae + Pitheciidae. In addition, the parasite and the molecular trees support close relationships betweenCallimicoandCallithrix/Cebuella.The study also makes apparent that the parasite tree generally portrays the results of other studies, both when they are congruous and when they are conflicting. This is interpreted to be additional evidence for close coevolution between the Platyrrhini and their specific pinworms. Because, whatever the combination of data being considered no consensus can be found on the exact position ofAotusandCallicebus,and because it is likely that the earliest radiation of the Platyrrhini could be comparable to an evolutionary burst, which renders identification of homologous characters difficult, it is suggested that, possibly, not enough discriminating tracks of the evolutionary paths have been conserved to allow to resolve this uncertainty in the future.     

Molecular evidence on Primate phylogeny from DNA sequences

Evidence from DNA sequences on the phylogenetic systematics of primates is congruent with the evidence from morphology in grouping Cercopithecoidea (Old World monkeys) and Hominoidea (apes and humans) into Catarrhini, Catarrhini and Platyrrhini (ceboids or New World monkeys) into Anthropoidea, Lemuriformes and Lorisiformes into Strepsirhini, and Anthropoidea, Tarsioidea, and Strepsirhini into Primates. With regard to the problematic relationships of Tarsioidea, DNA sequences group it with Anthropoidea into Haplorhini. In addition, the DNA evidence favors retaining Cheirogaleidae within Lemuriformes in contrast to some morphological studies that favor placing Cheirogaleids in Lorisiformes. While parsimony analysis of the present DNA sequence data provides only modest support for Haplorhini as a monophyletic taxon, it provides very strong support for Hominoidea, Catarrhini, Anthropoidea, and Strepsirhini as monophyletic taxa. The parsimony DNA evidence also rejects the hypothesis that megabats are the sister group of either Primates or Dermoptera (flying lemur) or a Primate-Dermoptera clade and instead strongly supports the monophyly of Chiroptera, with megabats grouping with microbats at considerable distance from Primates. In contrast to the confused morphological picture of sister group relationships within Hominoidea, orthologous noncoding DNA sequences (spanning alignments involving as many as 20,000 base positions) now provide by the parsimony criterion highly significant evidence for the sister group relationships defined by a cladistic classification that groups the lineages to all extant hominoids into family Hominidae, divides this ape family into subfamilies Hylobatinae (gibbons) and Homininae, divides Homininae into tribes Pongini (orangutans) and Hominini, and divides Hominini into subtribes Gorillina (gorillas) and Hominina (humans and chimpanzees). A likelihood analysis of the largest body of these noncoding orthologues and counts of putative synapomorphies using the full range of sequence data from mitochondrial and nuclear genomes also find that humans and chimpanzees share the longest common ancestry. © 1994 Wiley-Liss, Inc.     

Parasite load and brightness in lizards: an interspecific test of the Hamilton and Zuk hypothesis

Hamilton & Zuk (1982) hypothesized a positive correlation between a species' sexual showiness and its level of parasitic infection. We tested the hypothesis in 26 species of lizards, members of a class of vertebrates never before used to test the model. The prevalence of parasites was determined using published lists of parasites found in wild lizard populations. An index of showiness (brightness) was derived by scoring photographs of lizards in natural settings. Contrary to expectations of Hamilton & Zuk (1982), we found an inverse correlation between a lizard species' brightness and parasite prevalence. No correlation was found between a species' brightness and the number of parasite genera, species, or percentage of individual infecting parasite taxa. These results are discussed in relation to other interspecific tests of the hypothesis.     

Social parasites among African allodapine bees (Hymenoptera,Anthophoridae, Ceratinini)*

Among the numerous nonparasitic allodapine bees there are 11 known species with parasitic or probably parasitic habits. These species live in nests of their close relatives, the female parasite replacing an egg-layer of the host. Seven of the parasitic species are distributed among four otherwise nonparasitic genera, while four species of parasites are placed in three exclusively parasitic genera. The parasites have mostly arisen independently from different nonparasitic forms. There is much convergence among the parasitic forms involving such characters as the flattened or concave face, reduced eyes, reduced mouthparts, reduced wing venation, and reduced pollen-carrying scopa. In the most specialized parasitic genera the mouthparts are so small as to be almost surely useless for obtaining food from flowers. Such bees must feed in the host nest, and are not found on flowers. Their wings must be adequate to take them to a new host nest but the reduced venation and eyes must reflect the reduced locomotary and sensory needs of a bee that does not visit flowers. In this paper a new, presumably parasitic Allodapula is described as is a parasitic Braunsapis, a parasitic Allodape, and a Eucondylops. A previously described Macrogalea is recognized as a parasite for the first time. A new genus and species of parasites Nasutapsis straussorum, allied to Braunsapis, is also described. All these forms are from Africa.     

Classification of the family Plectonemertidae (Nemertea): a phenetic comparison

A phenetic classification based on overall morphological similarity between the species in the family Plectonemertidae (genera Plectonemertes, Campbellonemertes, Potamonemertes, Leptonemertes, Katechonemertes, Argonemertes, Anliponemertes, and Acteonemertes ) was undertaken and the result compared with a cladistic and an evolutionary classification. Similarity between species was computed by Gower's general coefficient of similarity and various techniques were used to find patterns in the similarity matrix: single-linkage, average-linkage, and complete-linkage clustering, together with principal coordinate analysis. Although the explicit aim of phenetics is not to estimate the phylogeny, the classification based on overall similarity still portrays phylogeny better than an intuitive assessment of morphological similarity, as judged by the cladistic analysis. The classification does not support the previously proposed hypothesis that the two freshwater genera Campbellonemertes and Potamonemertes have descended from a terrestrial ancestor.     

Monophyly and phylogeny of cuckoos (Aves, Cuculidae) inferred from osteological characters

A reanalysis of 32 characters from the literature previously deemed diagnostic of the Cuculidae revealed only five to be synapomorphic. I subsequently examined skeletons from 54 avian families and identified nine additional synapomorphies that supported cuckoo monophyly. My cladistic analysis of 33 cuculid genera using 135 skeletal characters differs markedly from currently accepted taxonomies. The most striking deviation is the placement of both New and Old World parasitic cuckoos in the Cuculinae, supporting the evolution of brood parasitism in a single event rather than three times as previously proposed. Unlike earlier classifications, the Cuculinae also includes the facultative parasites Coccyzus. This, suggests that the ancestral Coccyzus was an obligate parasite, and is consistent with the many behavioral adaptations to parasitism exhibited by this genus. Other changes include the placement of three subfamilies, comprising non-parasitic, terrestrial cuckoos of Old World (Centropodinae and Carpococcystinae) and New World (Neomorphinae) distribution, in basal positions on the tree. Nineteen characters support a sister relationship between the Hoatzin ( Opisthocamus hoatzin Müller) and turacos (Musophagidae), and not cuckoos. Three synapomorphies of the os carpi ulnare were found to unite the Cuculidae, turacos, and the Hoatzin, suggesting that these three diverse taxa may constitute a monophyletic group.     

The Ratchet and the Red Queen: the maintenance of sex in parasites

The adaptive significance of sexual reproduction remains as an unsolved problem in evolutionary biology. One promising hypothesis is that frequency‐dependent selection by parasites selects for sexual reproduction in hosts, but it is unclear whether such selection on hosts would feed back to select for sexual reproduction in parasites. Here we used individual‐based computer simulations to explore this possibility. Specifically, we tracked the dynamics of asexual parasites following their introduction into sexual parasite populations for different combinations of parasite virulence and transmission. Our results suggest that coevolutionary interactions with hosts would generally lead to a stable coexistence between sexual parasites and a single parasite clone. However, if multiple mutations to asexual reproduction were allowed, we found that the interaction led to the accumulation of clonal diversity in the asexual parasite population, which led to the eventual extinction of the sexual parasites. Thus, coevolution with sexual hosts may not be generally sufficient to select for sex in parasites. We then allowed for the stochastic accumulation of mutations in the finite parasite populations (Muller's Ratchet). We found that, for higher levels of parasite virulence and transmission, the population bottlenecks resulting from host–parasite coevolution led to the rapid accumulation of mutations in the clonal parasites and their elimination from the population. This result may explain the observation that sexual reproduction is more common in parasitic animals than in their free‐living relatives.     

Sympatric speciation and radiative evolution of socially parasitic ants - Heretic hypotheses and their factual background

According to current hypotheses the main types of social parasitism among ants, namely slavery, temporary parasitism, and inquilinism, arose from such features as predation on other ants, or territorial behavior, both presumed precursors of slavemaking, and polygyny, a presumed precursor of temporary parasitism and inquilinism. The latter is believed also to represent a final instar in several evolutionary pathways leading from slavery, temporary parasitism, and xenobiosis to this permanently parasitic, workerless condition. Speciation, the origin of parasitic species from their usually closely related host species, is suggested to occur due to temporary geographic isolation and subsequent transition of one of the newly formed daughter species to parasitism in the nests of the other. Evidence is presented suggesting that the main types of social parasitism originated independently of each other. 15 ant genera are parasitized exclusively by inquilines, Eve other genera exclusively by temporary parasites. Only four groups of non-parasitic ant species (Formica, Tet-ramorium, Leptothorax subgenera Leptothorax and Myrafant) have parasites of several types each. Within these roups, however, there is little evidence of evolutionary transitions from one type to another. The few exceptions, mainly workerless species of the genera Epimyrma and Chalepoxenus, represent parasites which clearly derive from slave-making congeners, but differ from ordinary inquilines in that they eliminate the host colony queens like their actively dulotic ancestors. The new hypothesis suggests that all forms of interspecific true social parasitism (excluding xenobiosis) orginated from a common “preparasitic” stage, a subpopulation of reproductives in polygynous colonies and species, with diverging sexual behavior (near-nest mating vs. swarming) and caste ratios (production of more sexuals vs. workers). Arguments for sympatric speciation are compiled. Various features of the ancestral, and then host species (colony sizes, population density and structure, transition from polygyny to monoyny, etc.), and of the “preparasite” (production of few, or no workers, etc.) may shape the developing parasite to become a slave-maker, inquiline, or temporary parasite. These features usually leave open only one, or in a few genera, several options. The different types of parasitism within one host species group thus may have developed in a radiative manner from the common, preparasitic stage, which explains that independent colony foundation is a common feature of all true social parasites among ants.     

Classification of the family Plectonemertidae (Nemertea): a phenetic comparison

A phenetic classification based on overall morphological similarity between the species in the family Plectonemertidae (genera Plectonemertes, Campbellonemertes, Potamonemertes, Leptonemertes, Katechonemertes, Argonemertes, Anliponemertes, and Acteonemertes) was undertaken and the result compared with a cladistic and an evolutionary classification. Similarity between species was computed by Gower's general coefficient of similarity and various techniques were used to find patterns in the similarity matrix: single-linkage, average-linkage, and complete-linkage clustering, together with principal coordinate analysis. Although the explicit aim of phenetics is not to estimate the phylogeny, the classification based on overall similarity still portrays phylogeny better than an intuitive assessment of morphological similarity, as judged by the cladistic analysis. The classification does not support the previously proposed hypothesis that the two freshwater genera Campbellonemertes and Potamonemertes have descended from a terrestrial ancestor.     

我国淡水鱼类粘孢子虫的支序分类学研究

本研究选取15个主要特征对我国淡水鱼类23属粘孢子虫的支序分类进行了分析.结果表明,根据这15个特征构建的经典分支系统树与现有分类系统较为一致;而许多被分子系统学证明有争议的特征,如尾孢虫的尾突,孢子和极囊的形状等在研究粘孢子虫的系谱发育中仍然有着重要作用,剔除了上述特征的分支系统树与经典的分支系统树相比,存在许多缺陷.嗜碘泡是区分粘体虫和碘泡虫的主要特征,然而剔除嗜碘泡特征的分支系统树与经典的分支系统树区别不大,因此,我们建议在这一方面和国际学术界统一起来,即不再把嗜碘泡作为区分碘泡虫和粘体虫的主要特征.     

Test of synergistic interaction between infection and inbreeding in Daphnia magna

Abstract It has been proposed that parasitic infections increase selection against inbred genotypes. We tested this hypothesis experimentally using pairs of selfed and outcrossed sibling lines of the freshwater crustacean Daphnia magna , which can be maintained clonally. We studied the performance of selfed relative to outcrossed sibling clones during repeated pairwise clonal competition in the presence and absence of two species of microsporidian parasites. In 13 of the 14 pairs, the selfed clones did worse than the outcrossed ones in the control treatment, but the presence of either parasite did not result in an overall increase in this difference. Rather, it decreased the performance of the selfed relative to the outcrossed sibling in some pairs and increased it in others. Moreover, the two parasite species did not have the same effect in a given pair. This indicates that, contrary to the hypothesis that parasites generally lead to a decreased performance of inbred genotypes, their effect may depend on the genetic background of the host as well as on the parasite species, and suggests that inbreeding can lead to reduced or increased resistance to parasites. Our findings also indicate that there is variation for specific resistance to different species of parasites in the meta-population from which the hosts for this study were obtained.     

A molecular phylogeny of malarial parasites recovered from cytochrome b gene sequences

A phylogeny of haemosporidian parasites (phylum Apicomplexa, family Plasmodiidae) was recovered using mitochondrial cytochrome b gene sequences from 52 species in 4 genera (Plasmodium, Hepatocystis, Haemoproteus, and Leucocytozoon), including parasite species infecting mammals, birds, and reptiles from over a wide geographic range. Leucocytozoon species emerged as an appropriate out-group for the other malarial parasites. Both parsimony and maximum-likelihood analyses produced similar phylogenetic trees. Life-history traits and parasite morphology, traditionally used as taxonomic characters, are largely phylogenetically uninformative. The Plasmodium and Hepatocystis species of mammalian hosts form 1 well-supported clade, and the Plasmodium and Haemoproteus species of birds and lizards form a second. Within this second clade, the relationships between taxa are more complex. Although jackknife support is weak, the Plasmodium of birds may form 1 clade and the Haemoproteus of birds another clade, but the parasites of lizards fall into several clusters, suggesting a more ancient and complex evolutionary history. The parasites currently placed within the genus Haemoproteus may not be monophyletic. Plasmodium falciparum of humans was not derived from an avian malarial ancestor and, except for its close sister species, P. reichenowi, is only distantly related to haemospordian parasites of all other mammals. Plasmodium is paraphyletic with respect to 2 other genera of malarial parasites, Haemoproteus and Hepatocystis. Explicit hypothesis testing supported these conclusions.     

Phylogeny, host-parasite relationship and zoogeography

Phylogeny is the evolutionary history of a group or the lineage of organisms and is reconstructed based on morphological, molecular and other characteristics. The genealogical relationship of a group of taxa is often expressed as a phylogenetic tree. The difficulty in categorizing the phylogeny is mainly due to the existence of frequent homoplasies that deceive observers. At the present time, cladistic analysis is believed to be one of the most effective methods of reconstructing a phylogenetic tree. Excellent computer program software for phylogenetic analysis is available. As an example, cladistic analysis was applied for nematode genera of the family Acuariidae, and the phylogenetic tree formed was compared with the system used currently. Nematodes in the genera Nippostrongylus and Heligmonoides were also analyzed, and the validity of the reconstructed phylogenetic trees was observed from a zoogeographical point of view. Some of the theories of parasite evolution were briefly reviewed as well. Coevolution of parasites and humans was discussed with special reference to the evolutionary relationship between Enterobius and primates.     

Phylogenetic systematics and evolution of primate-derived Pneumocystis based on mitochondrial or nuclear DNA sequence comparison

Previous studies have demonstrated that the agent of Pneumocystis pneumonia (PcP), Pneumocystis carinii, is actually a complex of eukaryotic organisms, and cophylogeny could explain the distribution of the hosts and parasites. In the present work, we tested the hypothesis of cophylogeny between the primate-derived Pneumocystis group and their hosts. Specific strains isolated from 20 primate species, including humans, were used to produce a phylogeny of the parasites. Aligned sequences corresponding to DNA sequences of three genes (DHPS, mtSSU-rRNA, and mtLSU-rRNA) were separately analyzed and then combined in a single data set. The resulting parasite phylogeny was compared with different controversial phylogenies for the hosts. This comparison demonstrated that, depending upon which topology is accepted for the hosts, at least 61% and perhaps 77% of the homologous nodes of the respective cladograms of the hosts and parasites may be interpreted as resulting from codivergence events. This finding and the high specificity of these parasites suggests that cophylogeny may be considered the dominant pattern of evolution for Pneumocystis organisms, representing a new example of parallel evolution between primates and their specific parasites. Because the phylogeny of Pneumocystis followed very closely the differentiation of their hosts at the species level, the study of the parasites could provide valuable information on the phylogeny of their hosts. We used this information to explore controversial hypotheses of the phylogeny of the Platyrrhini by comparison with the phylogeny of their specific Pneumocystis parasites. If these organisms were closely associated as lung parasites with primates through the ages, the hypothesis of the Pneumocystis spp. being new pathogenic agents could be refuted. However, these organisms are opportunistic symbionts, becoming pathogenic whenever the immunological defences of their hosts decline. This study also provides support for the hypothesis that the different Pneumocystis species are genetically independent organisms, helping to clarify their taxonomic status.     

Further revision of the caddisfly family Uenoidae (Trichoptera): evidence for inclusion of Neophylacinae and Thremmatidae

Abstract. A survey of characters within the Limnephilidae was made to test the cladistic hypothesis underlying traditional classification placing Neophylacinae as a subfamily of the Limnephilidae. Characters emerged which support an alternative hypothesis of phylogeny and classification, linking the Neophylacinae with the Thremmatidae and with the Uenoidae. The Uenoidae as defined here contain two monophyletic groups: subfamily Uenoinae containing the four genera Uenoa, Sericostriata, Neothremma and Farula previously constituting Uenoidae ( sensu Wiggins et al. , 1985), and subfamily Thremmatinae consisting of Thremma, Neophylax and Oligophlebodes. The new classification is shown to have predictive value for behaviour and ecology of the taxa.     

Phenetic and cladistic relationships among tenebrionid beetles (Coleoptera)

Abstract. The higher classification of Tenebrionidae is analysed using numerical phenetic, numerical cladistic and traditional Hennigian methods. In all, eighty characters are examined for about 335 taxa; definitive analyses are made on combinations of eighteen to seventy characters for thirty-three OTUs. At lower levels of relationship (genera and closely related tribes) phenetic and cladistic classifications are shown to be congruent, but at higher levels (tribes and subfamilies) there is marked discordance with phenetic results being more stable. A consensus classification is more similar to the Hennigian cladogram than is any single computer generated cladogram. Two main tribal groups – the Lagrioid and Tenebrionoid groups – are suggested which differ in defensive glands, female anatomy, wing and mouthpart morphology, larval characters and other features. The Tenebrionoid group consists of three main subdivisions – the tenebrionine, coelometopine and diaperine lineages. Changes in classificatory position are recommended for eighty-seven genera and tribes (listed in Appendix E) and implied for numerous others.     

Phylogenetic studies of Meloidae (Coleoptera), with emphasis on the evolution of phoresy

One of the most recent classifications of Meloidae is based on the assumption that phoretic first‐instar larvae evolved twice in the family, once in Meloinae and again in Nemognathinae. Within Meloinae, this scheme places all presumed phoretic taxa in Meloini regardless of other characteristics. This paper challenges this classification with a cladistic analysis of all meloid genera whose first‐instar larvae were available for study. It concludes that phoresy evolved several times in Meloinae alone and that Meloini, when defined to include all phoretic genera, is polyphyletic. Cladistic support also is presented for four subfamilies of Meloidae and for several of the traditional tribes recognized in recent classifications.     

Dissecting the effect of a heterogeneous environment on the interaction between host and parasite fitness traits

Environmental variation can alter the probability of parasitic infection or the fitness consequence of infection, and thus has the potential to dramatically alter the dynamics of host parasite coevolution. Here we investigated the effect of a changing temperature on host-parasite interactions using the crustacean Daphnia magna and its bacterial parasite Pasteuria ramosa. By reciprocally varying (1) the temperature at which exposure to parasites occurred and (2) the temperature at which within-host parasite growth occurred, and measuring several fitness-related traits, we show that while there are temperature combinations that favour either host or parasite, there are also conditions that favour neither, that is, negative fitness consequences for the host without fitness benefits for the parasite. This result highlights the importance of considering a heterogeneous rather than static environment in coevolutionary studies, while also showing support for an optimal virulence strategy in castrating parasites.     

Relatedness affects competitive performance of a parasitic plant (Cuscuta europaea) in multiple infections

Theoretical models predict that parasite relatedness affects the outcome of competition between parasites, and the evolution of parasite virulence. We examined whether parasite relatedness affects competition between parasitic plants (Cuscuta europaea) that share common host plants (Urtica dioica). We infected hosts with two parasitic plants that were either half-siblings or nonrelated. Relative size asymmetry between the competing parasites was significantly higher in the nonrelated infections compared to infections with siblings. This higher asymmetry was caused by the fact that the performance of some parasite genotypes decreased and that of others increased when grown in multiple infections with nonrelated parasites. This result agrees with the predictions of theories on the evolution of parasite virulence: to enhance parasite transmission, selection may favour reduced competition with genetically related parasites in hosts infected by several genotypes. However, in contrast to the most common predictions, nonrelated infections were not more virulent than the sibling infections.     

RUST FUNGI AND HOST PLANT COEVOLUTION: DO PRIMITIVE HOSTS HARBOR PRIMITIVE PARASITES?

Abstract— The classical view of rust phylogeny is that rusts found on ferns and conifers are primitive, while rusts that parasitize angiosperms are advanced. This belief was based on the theory that primitive hosts harbor primitive parasites; that is, it assumed coevolution (co-speciation) of hosts and parasites. A cladistic analysis of 30 genera and 28 characters representative of the major patterns of rust fungi diversity is presented. The results of this analysis suggest that tropical short-cycle rusts on angiosperms form the cladistically basal group of rusts, while the rusts on conifers and ferns (Melampsoraceae sensu lato ) form a nested terminal clade. These results suggest that rusts and their hosts have not undergone a long period of parallel cladogenesis (co-speciation); host transfer has probably been at least as frequent as co-speciation. The cladograms indicate evolutionary trends of spore stages and life history: urediniospores evidently preceded the evolution of aeciospores and pycniospores within Uredinales, and heteroecism is a derived condition which evolved at least several times. This study stresses the importance of making use of independent cladistic analyses of both host and parasite in order to test assumptions of coevolution and host transfer.