New World monkey phylogeny based on X-linked G6PD DNA sequences

The Platyrrhini, or New World monkeys, are an infraorder of Primates comprised of 16 genera. Molecular phylogenetic analyses have consistently sorted these genera into three groups: the Pitheciidae (e.g., saki and titi monkeys), Atelidae (e.g., spider and howler monkeys), and Cebidae (e.g., night monkeys, squirrel monkeys, and tamarins). No consensus has emerged on the relationships among the three groups or within the Cebidae. Here, approximately 0.8 kb of newly generated intronic DNA sequence data from the X-linked glucose-6-phosphate dehydrogenase (G6PD) locus have been collected from nine New World monkey taxa to examine these relationships. These data are added to 1.3 kb of previously generated G6PD intronic DNA sequence data [Mol. Phylogenet. Evol. 11 (1999) 459]. Using distance and parsimony-based techniques, G6PD sequences provide support for an initial bifurcation between the Pitheciidae and the remaining platyrrhines, linking Atelidae and Cebidae as sister taxa. Bayesian methods provided a conflicting phylogeny with Atelidae as outgroup. Within the Cebidae, a sister relation between Aotus and the Cebus/Saimiri clade is favored by parsimony analysis, but not by other analyses. Potential reasons for the difficulty in resolving family level New World monkey phylogenetics are discussed.     

Phylogenetic relationships and divergence times among New World monkeys (Platyrrhini, Primates)

Orthologous sequences of six nuclear genes were obtained for all recognized genera of New World monkeys (Primates: Platyrrhini) and outgroups to evaluate the phylogenetic relationships and to estimate divergence times. Phylogenetic relationships were reconstructed by maximum parsimony, maximum likelihood, and Bayesian approaches. All methods resolved with 100% branch support genus-level relationships, except for the grouping of Aotus as a sister taxa of Cebus and Saimiri, which was supported by low bootstrap percentages and posterior probability. All approaches depict three monophyletic New World monkey families: Atelidae, Cebidae, and Pitheciidae; also within each family, all approaches depict the same branching topology. However, the approaches differ in depicting the relationships of the three families to one another. Maximum parsimony depicts the Atelidae and Cebidae as sister families next joined by the Pitheciidae. Conversely, likelihood and Bayesian phylogenetic trees group families Atelidae and Pitheciidae together to the exclusion of Cebidae. Divergence time estimations using both local molecular clock and Bayesian approaches suggest the families diverged from one another over a short period of geological time in the late Oligocene-early Miocene.     

Retropositional events consolidate the branching order among New World monkey genera

Due to contradicting relationships obtained from various morphological and genetic studies, phylogenetic relationships among New World monkey genera are highly disputed. In the present study, we analyzed the presence/absence pattern of 128 SINE integrations in all New World monkey genera. Among them, 70 were specific for only a single genus, whereas another 18 were present in all New World monkey genera. The 40 remaining insertions were informative to elucidate phylogenetic relationships among genera. Several of them confirmed the monophyly of the three families Cebidae, Atelidae and Pitheciidae as well as of the subfamily Callithrichinae. Further markers provided evidence for a sister grouping of Cebidae and Atelidae to the exclusion of Pitheciidae as well as for relationships among genera belonging to Callithrichinae and Atelidae. Although a close affiliation of Saimiri, Aotus and Cebus to Callithrichinae was shown, the relationships among the three genera remained unresolved due to three contradicting insertions.     

Williams-Beuren mapping in Callithrix argentata, Callicebus cupreus and Alouatta caraya indicates different patterns of chromosomal rearrangements in neotropical primates

Human chromosome 7 has a complex syntenic origin. It was divided into two segments in both the ancestral primate karyotype and in Platyrrhini. Apparently, a small segment in the ancestral platyrrhine karyotype was associated with HSA5 and the remainder formed a middle‐sized submetacentric. We tested the dynamics of platyrrhine chromosomes by hybridizing the locus specific Willams‐Beuren probe (7q 11.23, 450 kb) to chromosomes of representative species from the three families of the New World monkeys recently proposed by molecular genomics: Cebidae, Callithrix argentata (bare ear marmoset or silvery marmoset, 2n = 44); Pitheciidae, Callicebus cupreus [red titi monkey, or coppery monkey, 2n = 46)] and Atelidae, Alouatta caraya (black and gold howler, 2n = 52). In both the marmoset and the howler monkeys, the signal was found on the small segment of chromosome 7 associated with human chromosome 5, but not in Callicebus cupreus. Instead, the Williams‐Beuren syndrome (WS) signal was found on a C. cupreus chromosome previously reported to be hybridized only by human chromosome 1. The WS probe indicates a small, but complex translocation never described before. Our results point out that fluorescence in situ hybridization (FISH) with locus specific probes and cloned DNA fragments such as bacterial aftificial chromosomes (BACs) provides higher resolution than FISH with whole chromosomes paints. It may be well that the variability seen in the hybridization patterns and revealed by the WS FISH in this report is as a result of a rearrangement ‘hot spot’. The WS region in humans is composed of region‐specific different blocks of complex segmental duplications that probably promote the extraordinary rate of evolutionary dynamics of this region among primate species, and which continues to be reflected today by the predisposition of this region to disease syndromes such as WS. The evolutionary history of this region also suggests that repeat families in this region had their origin in a common ancestor of both Old World and New World monkeys.     

Molecular phylogeny of the New World monkeys (Platyrrhini,primates) based on two unlinked nuclear genes: IRBP intron 1 and ϵ-globin sequences

Nuclear sequences of the 1.8 kilobase (kb) long intron 1 of the interstitial retinol-binding protein gene (IRBP), previously determined for 11 of the 16 extant genera of New World monkeys (superfamily Ceboidea, infraorder Platyrrhini), have now been determined for the remaining 5 genera. The maximum parsimony trees found, first with IRBP sequences alone and then with tandemly combined IRBP and ϵ-globin gene sequences from the same species, supported a provisional cladistic classification with the following clusters. Subtribes Callitrichina (Callithrix, Cebuella), Callimiconina (Callimico), Leontopithecina (Leontopithecus) and Saguina (Saguinus) constitute subfamily Callitrichinae, and subfamilies Callitrichinae, Aotinae (Aotus), and Cebinae (Cebus, Saimiri) constitute family Cebidae. Subtribes Chiropotina (Chiropotes, Cacajao) and Pitheciina (Pithecia) constitute tribe Pitheciini; and tribes Pitheciini and Callicebini (Callicebus) constitute subfamily Pitheciinae. Subtribes Brachytelina (Brachyteles, Lagothrix) and Atelina (Ateles) constitute tribe Atelini, and tribes Atelini and Alouattini (Alouatta) constitute subfamily Atelinae. The parsimony results were equivocal as to whether Pitheciinae should be grouped with Atelinae in family Atelidae or have its own family Pitheciidae. The cladistic groupings of extant ceboids were also examined by different stochastic evolutionary models that employed the same stochastic process of nucleotide substitutions but alternative putative phylogenetic trees on which the nucleotide substitutions occurred. Each model, i.e., each different tree, predicted a different multinomial distribution of nucleotide character patterns for the contemporary sequences. The predicted distributions that were closest to the actual observed distributions identified the best fitting trees. The cladistic relationships depicted in these best fitting trees agreed in almost all cases with those depicted in the maximum parsimony trees. © 1996 Wiley-Liss, Inc.     

Development and annotation of shotgun sequence libraries from New World monkeys

The draft genome sequences of several primates are available, providing insights into evolutionary and anthropological research. However, genomic resources from New World monkeys are conspicuously lacking. To date, the genomes of only two platyrrhine species, the common marmoset and the Bolivian squirrel monkey, have been fully sequenced. This is especially limiting for comparative genomics research, considering that New World monkeys are the most speciose primate group, and platyrrhine genetic diversity is comparable to that of the catarrhines (i.e. apes and Old World monkeys). Here, we present the generation and annotation of numerous sequence reads from the genomes of Spider monkey (Ateles belzebuth), Owl monkey (Aotus lemurinus) and Uakari (Cacajao calvus), representing the three platyrrhine families, Atelidae, Cebidae and Pitheciidae, respectively. These sequencing reads were developed from gDNA shotgun libraries containing over 3000 individual sequences with an average length of 726 bps. Of these sequences, 1220 contain <20% repeats, and thus are potentially highly useful phylogenetic markers for other platyrrhine species. Among them, a large number of sequencing reads were found to match unique regions within the human (2462 sequences) and the marmoset (2829 sequences) genomes. In particular, the majority of these sequencing reads are from putatively neutrally evolving intergenic regions. Thus, they are likely to be highly informative for inferring neutral evolutionary patterns and genomic evolution for other New World monkeys.     

The phylogenetic system of primates—character evolution in the light of a consolidated tree

Molecular analyses of the last decades helped solving the major open questions on the external and internal phylogenetic relationships of primates. The present review uses these data for the inference of character evolution along the branches of the primate tree. Altogether, more than 200 evolutionary changes in hard and soft tissue anatomy/morphology, behavior, physiology, and protein constitution are presented in the context of their functional relevance and adaptive value. The compilation focuses on primates as a whole and on the higher-ranked primate subtaxa with living representatives: Strepsirhini: Lorisiformes, Galagidae, Lorisidae, Lemuriformes; Haplorhini: Tarsioidea, Anthropoidea, Platyrrhini, Atelidae + Cebidae, Atelidae, Cebidae, Aotinae, Callithrichinae, Cebinae, Pitheciidae, Pithecinae, Catarrhini, Cercopithecoidea, Cercopithecinae, Colobinae, Colobini, and Hominoidea. Within Hominoidea character evolution is traced down to more peripheral branches: Hylobatidae, Hominidae, Pongo, Homininae, Gorilla, Pan + Homo, Pan, and modern humans. Character states in extinct representatives of Plesiadapiformes, Omomyoidea, Propliopithecidae, Hominini, etc. are always taken into account; they are presented in detail whenever character-state distribution in living species is ambiguous or misleading. The taxonomic sample and the characters included combine to a phylogenetic system that illustrates primate evolution and diversity. The data presented additionally provide a detailed picture of the evolutionary steps and trends involved in hominization. Reflections on the frequently underestimated role of polymorphisms in phylogenetic analyses complete the survey.     

Color vision and niche partitioning in a diverse neotropical primate community in lowland Amazonian Ecuador

A recent focus in community ecology has been on how within‐species variability shapes interspecific niche partitioning. Primate color vision offers a rich system in which to explore this issue. Most neotropical primates exhibit intraspecific variation in color vision due to allelic variation at the middle‐to‐long‐wavelength opsin gene on the X chromosome. Studies of opsin polymorphisms have typically sampled primates from different sites, limiting the ability to relate this genetic diversity to niche partitioning. We surveyed genetic variation in color vision of five primate species, belonging to all three families of the primate infraorder Platyrrhini, found in the Yasuní Biosphere Reserve in Ecuador. The frugivorous spider monkeys and woolly monkeys (Ateles belzebuth and Lagothrix lagotricha poeppigii, family Atelidae) each had two opsin alleles, and more than 75% of individuals carried the longest‐wavelength (553–556 nm) allele. Among the other species, Saimiri sciureus macrodon (family Cebidae) and Pithecia aequatorialis (family Pitheciidae) had three alleles, while Plecturocebus discolor (family Pitheciidae) had four alleles—the largest number yet identified in a wild population of titi monkeys. For all three non‐atelid species, the middle‐wavelength (545 nm) allele was the most common. Overall, we identified genetic evidence of fourteen different visual phenotypes—seven types of dichromats and seven trichromats—among the five sympatric taxa. The differences we found suggest that interspecific competition among primates may influence intraspecific frequencies of opsin alleles. The diversity we describe invites detailed study of foraging behavior of different vision phenotypes to learn how they may contribute to niche partitioning.     

Molecular Evidence for Parallel Evolution of Adaptive Syndromes in Fig-BreedingLissocephala(Drosophilidae)

AfrotropicalLissocephala(Drosophilidae) breed strictly in syconia (figs) ofFicus(Moraceae) and have accordingly evolved specific features including modified female and eggshell morphologies, ovipositing, larval foraging, and mating behaviors. These various traits may exist as two or three alternative states. Each species displays a specific suite of traits so closely coordinated with one another that alternative states of the overall suites of traits can be seen as “adaptive syndromes.” Three clear-cut adaptive syndromes can be recognized while two taxonomic lineages (junctaandsanuspecies groups) are traditionally accepted on the basis of male terminalia. A crucial evolutionary question results from the consideration that ecological clusters and taxonomic groups have conflicting compositions: the three syndromes are found in thejunctagroup while two of them occur in thesanugroup. To resolve this conflict, we present molecular data which provide a robust phylogeny: mitochondrial DNA (12S + 16S ribosomal DNA and cytochromeb) sequence data are in agreement with one another regardless of the algorithm used. All molecular data consistently support male terminalia dichotomy. Such a level of consistency unambiguously indicates that parallel evolution of adaptive syndromes occurred. Thus, homoplasy may affect morphological and behavioral traits concomitantly when these are involved in a network of functional relationships.     

Cophylogenetic analysis of lice in the Colpocephalum complex (Phthiraptera: Amblycera)

The chewing louse genus Colpocephalum parasitizes nearly a dozen distantly related orders of birds. Such a broad host distribution is relatively unusual in lice. However, the monophyly of the genus Colpocephalum has never been tested using molecular characters. Using one nuclear and one mitochondrial gene, we inferred a phylogeny for 54 lice from the genus Colpocephalum and other morphologically similar genera. The resulting phylogeny demonstrates that Colpocephalum itself is not monophyletic. However, these data support the existence of a Colpocephalum complex within which several lineages are restricted to particular host orders. These lineages corresponded to previously described genera, some of which are morphologically distinct and currently considered subgenera. Maddison–Slatkin tests were performed on the resulting phylogeny and showed that host order, host family and biogeographic region had significant phylogenetic signal when mapped onto the Colpocephalum complex phylogeny. A PARAFIT analysis comparing the overall Colpocephalum complex phylogeny to a host phylogeny revealed significant congruence between host and parasite trees. We also compared the cophylogenetic history of Colpocephalum and their hosts to that of a second distantly related feather louse genus, Degeeriella, which also infests diurnal birds of prey. Using PARAFIT to identify individual host–parasite links that contributed to overall congruence, there was no evidence of correlated cophylogenetic patterns between these two louse groups, suggesting that their host distribution patterns have been shaped by different evolutionary processes.     

Alu insertion loci and platyrrhine primate phylogeny

Short INterspersed Elements (SINEs) make very useful phylogenetic markers because the integration of a particular element at a location in the genome is irreversible and of known polarity. These attributes make analysis of SINEs as phylogenetic characters an essentially homoplasy-free affair. Alu elements are primate-specific SINEs that make up a large portion of the human genome and are also widespread in other primates. Using a combination wet-bench and computational approach we recovered 190 Alu insertions, 183 of which are specific to the genomes of nine New World primates. We used these loci to investigate branching order and have produced a cladogram that supports a sister relationship between Atelidae (spider, woolly, and howler monkeys) and Cebidae (marmosets, tamarins, and owl monkeys) and then the joining of this two family clade to Pitheciidae (titi and saki monkeys). The data support these relationships with a homoplasy index of 0.00. In this study, we report one of the largest applications of SINE elements to phylogenetic analysis to date, and the results provide a robust molecular phylogeny for platyrrhine primates.     

Modularity in attachment organs of African Cichlidogyrus (Platyhelminthes: Monogenea: Ancyrocephalidae) reflects phylogeny rather than host specificity or geographic distribution

Cichlidogyrus spp. (Monogenea, Ancyrocephalidae) are common parasites of cichlid fishes from Africa and the Levant. They display important morphological variation in their attachment apparatus and infect a broad host spectrum throughout a wide geographic range. Thus, they offer an interesting model to investigate to what extent the phenotypic variability of the attachment organ among congeners is related to host specificity, geographic/environmental components, or phylogeny. A geometric morphometric approach was carried out to analyse the shape variation of sclerotized structures of the attachment organ within 66 African species of the genus Cichlidogyrus. The interspecific shape comparison supports the presence of three main morphological configurations, each consisting of a given combination of particular sclerite shapes. Moreover, data emphasize strong coordination and integration (shape co‐variation) among the different sclerites jointly forming the attachment organ. Although attachment apparatuses are usually considered to be the result of adaptive processes and must be adapted to the hosts and local environmental conditions, we found no relationship between these clusters and host specificity or geographical distribution. Nevertheless, groups are partially congruent with those obtained with the molecular phylogeny of a subset of species, suggesting a phylogenetic constraint rather than an adaptation to either hosts or environment. Because of the necessity to form a functional entity, modularity within attachment organ imposes important evolutionary constraint. This provides new insights into the evolvability of attachment organs, as well as into the morphological basis of host specificity and host–parasite co‐evolutionary interaction in helminth parasites. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 694–706.     

Geophagy in new world monkeys (Platyrrhini): ecological and geographic patterns

Geophagy has been recorded in an increasing number of New World monkeys (Platyrrhini) over recent years, permitting a tentative analysis of ecological patterns. While geophagy has now been recorded in species representing all 4 platyrrhine families and a majority of genera, there is a marked tendency for it to occur in the larger-bodied Pitheciidae and Atelidae. Howlers (Alouatta) are responsible for almost a third of reports, which are concentrated in the more frugivorous species, Alouatta belzebul and Alouatta seniculus. Geophagy may also be relatively common in the spider monkeys (Ateles) and the pitheciids, which are specialised frugivores and seed predators, respectively. An overview of the available data points to a marked Amazonian bias, allowing for geographical differences in the number of species and field studies. This pattern is demonstrated most emphatically by Alouatta, for which there are almost as many reports as field studies in the Amazon basin, in stark contrast with Central American sites, which have a long tradition of fieldwork, but no published records of geophagy. There are also relatively few reports from the Brazilian Atlantic forest. Despite the growth in reports, and the patterns identified here, the functional aspects of geophagy in the platyrrhines still remain unclear.     

Spider monkey,Muriqui and Woolly monkey relationships revisited

The taxonomic relationships among the four genera of the Atelidae family, Alouatta (Howler), Ateles (Spider), Lagothrix (Woolly) and Brachyteles (Muriqui), have been the subject of great debate. In general, almost all authors agree with the assignment of Howler monkeys as the basal genus, either in its own tribe Alouattini or in the subfamily Alouattinae, but they disagree on the associations among the other members of the family. Muriquis have been grouped with Spider monkeys based on the fact that they share various behavioral and morphological characteristics. Cladistic analyses using morphological, biochemical, karyotype and behavioral characteristics depicted a phylogenetic tree that places Howler as the basal genus and the remaining genera in an unresolved politomy. More recent studies using molecular data have suggested that Muriqui and Woolly monkeys are sister groups. However, a recent study based on nuclear and mtDNA argued that politomy is what best represents the relationships among Spider, Woolly and Muriqui. To contribute to this debate we have added new data from two nuclear genes, Transferrin and von Willebrand Factor, and using an alignment of 17,997 bp we demonstrate that a total analysis strongly supports the Muriqui-Woolly clade. A gene-to-gene approach showed that four of the eight nuclear genes provide support for the Muriqui-Woolly clade, two strongly and two moderately, while none of the eight genes provide support for any alternative arrangement. The mitochondrial genes were not able to resolve the politomy. A possible reason for the difficulty in resolving atelid relationships may be the short period of time separating each cladogenetic event in the evolutionary process that shaped this family.     

First report of filarial nematodes in free-living pitheciid primates

Although little studied, infections with nematodes of the Onchocercidae Leiper, 1911, predominated by the genera Dipetalonema Diesing, 1861 and Mansonella Faust, 1929, are frequent in wild primates and human populations in the Neotropical forest areas. This study reports natural infections with Dipetalonema freitasi Bain, Diagne & Muller, 1987 and D. gracile (Rudolphi, 1809) in two free-living species of pitheciid primates, extending the known geographical distribution of these species to the forest of the Peruvian Amazon. Adult worms were recovered from the thoracic and abdominal cavities of two species of monkeys, Pithecia monachus monachus (É. Geoffroy Saint-Hilaire) and Cacajao calvus ucayalii (Thomas) (Primates: Pitheciidae), collected along the Yavari-Mirin River basin and analysed via light and scanning electron microscopy. Both host species represent new host records for D. freitasi and D. gracile. Morphometric data are also presented for the sampled filarial worms in addition to morphological details obtained through light and electron microscopy examination of D. freitasi specimens.

     

Can molecular data place each neotropical monkey in its own branch?

Four different DNA datasets, representative of all extant neotropical primate genera, were tandemly aligned, comprising some 6,763 base pairs (bp) with 2,086 variable characters and 674 informative sites. Maximum Parsimony, Maximum Likelihood and Neighbor-Joining analyses suggested three monophyletic families (Atelidae, Pitheciidae and Cebidae) that emerged almost at the same time during primate radiation. Combined molecular data showed congruent branching inside the atelid clade, placing Alouatta as the most basal lineage followed by Ateles and a more derived branch including Brachyteles and Lagothrix as sister groups. In the Pitheciidae, Callicebus was the most basal lineage with respect to Pithecia and to the more derived sister groups (Cacajao and Chiropotes). Conjoint analysis strongly supported the monophyly of the Cebidae, grouping Aotus, Cebus and Saimiri with the small callitrichines. Within callitrichines, Cebuella merged with Callithrix, Callimico appeared as a sister group of Callithrix/Cebuella, Leontopitecus as a sister group of the previous clade, and Saguinus was the earliest callitrichine offshoot. Two major points remained to be clarified in platyrrhine phylogeny: (i) the exact branching pattern of Aotus, Cebus, Saimiri and the callitrichines, and (ii), which two of these three families (Atelidae, Pitheciidae and Cebidae) are more closely related to one another.     

Looks can deceive: Molecular phylogeny of a family of flatworm ectoparasites (Monogenea: Capsalidae) does not reflect current morphological classification

The morphological based taxonomy of highly derived parasite groups is likely to poorly reflect their evolutionary relationships. The taxonomy of the monogenean family Capsalidae, which comprises approximately 180 species of flatworm parasites that predominantly attach to external surfaces of chondrichthyan and teleost fishes, is based mainly on six morphological characters. The phylogenetic history of the family is largely unknown. We reconstructed the phylogenetic relationships of 47 species in 20 genera from eight of the nine subfamilies, from nucleotide sequences of three unlinked nuclear genes, 28S ribosomal RNA, Histone 3 and Elongation Factor 1 α. Our phylogeny was well corroborated, with 75% of branches receiving strong support from both Bayesian posterior probabilities and maximum likelihood bootstrap proportions and all nodes showed positive partitioned likelihood support for each of the three genes. We found that the family was monophyletic, with the Gyrodactylidae and Udonellidae forming the sister group. The Capsalinae was monophyletic, however, our data do not support monophyly for the Benedeniinae, Entobdellinae and Trochopodinae. Monophyly was supported for Capsala, Entobdella, Listrocephalos, Neobenedenia and Tristoma, but Benedenia and Neoentobdella were polyphyletic. Comparisons of the distribution of character states for the small number of morphological characters on the molecular phylogeny show a high frequency of apparent homoplasy. Consequently the current morphological classification shows little correspondence with the phylogenetic relationships within the family.     

Isotopic insight into host–endosymbiont relationships in Liolaemid lizards

Nitrogen isotopes have been widely used to investigate trophic levels in ecological systems. Isotopic enrichment of 2–5‰ occurs with trophic level increases in food webs. Host–parasite relationships deviate from traditional food webs in that parasites are minimally enriched relative to their hosts. Although this host–parasite enrichment pattern has been shown in multiple systems, few studies have used isotopic relationships to examine other potential symbioses. We examined the relationship between two gut-nematodes and their lizard hosts. One species, Physaloptera retusa, is a documented parasite in the stomach, whereas the relationship of the other species, Parapharyngodon riojensis (pinworms), to the host is putatively commensalistic or mutualistic. Based on the established trophic enrichments, we predicted that, relative to host tissue, parasitic nematodes would be minimally enriched (0–1‰), whereas pinworms, either as commensals or mutualists, would be significantly enriched by 2–5‰. We measured the ¹⁵N values of food, digesta, gut tissue, and nematodes of eight lizard species in the family Liolaemidae. Parasitic worms were enriched 1±0.2‰ relative to host tissue, while the average enrichment value for pinworms relative to gut tissue was 6.7±0.2‰. The results support previous findings that isotopic fractionation in a host–parasite system is lower than traditional food webs. Additionally, the larger enrichment of pinworms relative to known parasites suggests that they are not parasitic and may be several trophic levels beyond the host.     

Analysis of the heterochromatin of <Emphasis Type="Italic">Cebus</Emphasis> (Primates,Platyrrhini) by micro-FISH and banding pattern comparisons

The karyotype of the neotropical primate genus Cebus (Platyrrhini: Cebidae), considered the most ancestral one, shows the greatest amount of heterochromatin described among Platyrrhini genera. Banding techniques and restriction enzyme digestion have previously revealed great variability of quantity and composition of heterochromatin in this genus. In this context, we use fluorescence in situ hybridization (FISH) to analyse this genomic region and discuss its possible role in the diversification of Cebus. We used a heterochromatin probe for chromosome 11 of Cebus libidinosus (11qHe+ CLI probe), obtained by chromosome microdissection. Twenty-six specimens belonging to the families Atelidae, Cebidae, Callitrichidae and Pithecidae (Platyrrhini) were studied. Fourteen out of 26 specimens were Cebus (Cebidae) individuals of C. libidinosus, C. xanthosternos, C. apella, C. nigritus, C. albifrons, C. kaapori and C. olivaceus. In Cebus specimens, we found 6 to 22 positive signals located in interstitial and telomeric positions along the different species. No hybridization signal was observed among the remaining Ceboidea species, thus reinforcing the idea of a Cebus-specific heterochromatin composed of a complex system of repetitive sequences.     

Co‐evolutionary patterns in congeneric monogeneans: a review of Dactylogyrus species and their cyprinid hosts

Patterns associated with the evolution of parasite diversity, speciation and diversification were analysed using Dactylogyrus species (gill monogeneans) and their cyprinid hosts as a model. The aim of this study was to use this highly specific host–parasite systems to review: (1) the diversity and distribution of Dactylogyrus species, (2) the patterns of organization and structure of Dactylogyrus communities, (3) the evolution and determinants of host specificity and (4) the mode of Dactylogyrus speciation and co‐evolutionary patterns in this Dactylogyrus–cyprinid systems. Dactylogyrus are a highly diverse group of parasites, with their biogeography and distribution clearly linked to the evolutionary history of their cyprinid hosts. The coexistence of several Dactylogyrus species on one host is facilitated by increasing niche distances and the differing morphology of their reproductive organs. The positive interspecific and intraspecific interactions seem to be the most important factors determining the structure of Dactylogyrus communities. Host specificity is partially constrained by parasite phylogeny. Being a strict specialist is an ancestral character for Dactylogyrus, being the intermediate specialists or generalists are the derived characters. The evolution of attachment organ morphology is associated with both parasite phylogeny and host specificity. Considering larger and long‐lived hosts or hosts with several ecological characters as the measures of resource predictability, specialists with larger anchors occurred on larger or longer‐living fish species. Intra‐host speciation, a mode of speciation not often recorded in parasites, was observed in Dactylogyrus infecting sympatric cyprinids. Sister parasite species coexisting on the same host occupied niches that differed in at least one niche variable. Intra‐host speciation, however, was not observed in Dactylogyrus species of congeneric hosts from geographically isolated areas, which suggested association by descent and host‐switching events.