Hybridization is continually documented in primates, but effects of natural and anthropogenic hybridization on biodiversity are still unclear and differentiating between these contexts remains challenging in regards to primate evolution and conservation. Here, we examine hybridization effects on the mitochondrial DNA (mtDNA) control region of Callithrix marmosets, which provide a unique glimpse into interspecific mating under distinct anthropogenic and natural conditions. DNA was sampled from 40 marmosets along a 50-km transect from a previously uncharacterized hybrid zone in NE Brazil between the ranges of Callithrix jacchus and Callithrix penicillata. DNA was also collected from 46 marmosets along a 30-km transect in a hybrid zone in Rio de Janeiro state, Brazil, where exotic marmosets appeared in the 1980s. Combining Callithrix DNA sampled inside and outside of these hybrid zones, phylogenetic and network analyses show C. jacchus and C. penicillata being parental species to sampled hybrids. We expand limited Callithrix population genetics work by describing mtDNA diversity and demographic history of these parental species. We show ancient population expansion in C. jacchus and historically constant population size in C. penicillata, with the latter being more genetically diverse than the former. The natural hybrid zone contained higher genetic diversity relative to the anthropogenic zone. While our data suggest hybrid swarm formation within the anthropogenic zone due to removed physical reproductive barriers, this pattern is not seen in the natural hybrid zone. These results suggest different genetic dynamics within natural and anthropogenic hybridization contexts that carry important implications for primate evolution and conservation.

This study investigated rickettsial infection in Amblyomma auricularium ticks from the state of Pernambuco, northeastern Brazil. An engorged female of A. auricularium collected from a skunk (Conepatus semistriatus) was sent alive to the laboratory, where the female was found through molecular analysis to be infected by Rickettsia amblyommii. This engorged female oviposited, and its offspring was reared through three consecutive generations, always using tick-naïve rabbits to feed the ticks. PCR performed on five egg pools, 10 larvae, 10 nymphs, and 10 adults of each of the three generations always yielded rickettsial DNA, indicating maintenance of rickettsial infection in the ticks by transstadial and transovarial passages. DNA sequences of random PCR products from eggs, larvae, nymphs, and adults were identified as R. amblyommii. All infested rabbits seroconverted to R. amblyommii antigens at the 21(st) day after infestation, indicating that larvae, nymphs, and adults transmitted R. amblyommii through parasitism. However, no infested rabbit presented fever or any clinical alteration during the experimental period. Rickettsiae were successfully isolated from the two A. auricularium females, and the isolates were established in Vero cell culture. Molecular characterization of the isolates confirmed R. amblyommii by sequencing partial gltA, ompA, and ompB genes. From another sample of 15 A. auricularium adult ticks collected from two armadillos (Euphractus sexcinctus), eight (53.3%) were infected by R. amblyommii. This study reports R. amblyommii infecting the tick A. auricularium for the first time. This is also the first report of rickettsia infecting ticks in the northeastern region of Brazil.

Background Callithrix marmosets are a relatively young primate radiation, whose phylogeny is not yet fully resolved. These primates are naturally para- and allopatric, but three species with highly invasive potential have been introduced into the southeastern Brazilian Atlantic Forest by the pet trade. There, these species hybridize with each other and endangered, native congeners. We aimed here to reconstruct a robust Callithrix phylogeny and divergence time estimates, and identify the biogeographic origins of autochthonous and allochthonous Callithrix mitogenome lineages. We sequenced 49 mitogenomes from four species (C. aurita, C. geoffroyi, C. jacchus, C. penicillata) and anthropogenic hybrids (C. aurita x Callithrix sp., C. penicillata x C. jacchus, Callithrix sp. x Callithrix sp., C. penicillata x C. geoffroyi) via Sanger and whole genome sequencing. We combined these data with previously published Callithrix mitogenomes to analyze five Callithrix species in total. Results We report the complete sequence and organization of the C. aurita mitogenome. Phylogenetic analyses showed that C. aurita was the first to diverge within Callithrix 3.54 million years ago (Ma), while C. jacchus and C. penicillata lineages diverged most recently 0.5 Ma as sister clades. MtDNA clades of C. aurita, C. geoffroyi, and C. penicillata show intraspecific geographic structure, but C. penicillata clades appear polyphyletic. Hybrids, which were identified by phenotype, possessed mainly C. penicillata or C. jacchus mtDNA haplotypes. The biogeographic origins of mtDNA haplotypes from hybrid and allochthonous Callithrix were broadly distributed across natural Callithrix ranges. Our phylogenetic results also evidence introgression of C. jacchus mtDNA into C. aurita. Conclusion Our robust Callithrix mitogenome phylogeny shows C. aurita lineages as basal and C. jacchus lineages among the most recent within Callithrix. We provide the first evidence that parental mtDNA lineages of anthropogenic hybrid and allochthonous marmosets are broadly distributed inside and outside of the Atlantic Forest. We also show evidence of cryptic hybridization between allochthonous Callithrix and autochthonous C. aurita. Our results encouragingly show that further development of genomic resources will allow to more clearly elucidate Callithrix evolutionary relationships and understand the dynamics of Callithrix anthropogenic introductions into the Brazilian Atlantic Forest.

Animal hybridization is well documented, but evolutionary outcomes and conservation priorities often differ for natural and anthropogenic hybrids. Among primates, an order with many endangered species, the two contexts can be hard to disentangle from one another, which carries important conservation implications. Callithrix marmosets give us a unique glimpse of genetic hybridization effects under distinct natural and human-induced contexts. Here, we use a 44 autosomal microsatellite marker panel to examine genome-wide admixture levels and introgression at a natural C. jacchus and C. penicillata species border along the São Francisco River in NE Brazil and in an area of Rio de Janeiro state where humans introduced these species exotically. Additionally, we describe for the first time autosomal genetic diversity in wild C. penicillata and expand previous C. jacchus genetic data. We characterize admixture within the natural zone as bimodal where hybrid ancestry is biased toward one parental species or the other. We also show evidence that São Francisco River islands are gateways for bidirectional gene flow across the species border. In the anthropogenic zone, marmosets essentially form a hybrid swarm with intermediate levels of admixture, likely from the absence of strong physical barriers to interspecific breeding. Our data show that while hybridization can occur naturally, the presence of physical, even if leaky, barriers to hybridization is important for maintaining species genetic integrity. Thus, we suggest further study of hybridization under different contexts to set well informed conservation guidelines for hybrid populations that often fit somewhere between “natural” and “man-made.”

We provide here a current overview of marmoset (Callithrix) evolution, hybridization, species biology, basic/biomedical research, and conservation initiatives. Composed of 2 subgroups, the aurita group (C aurita and C flaviceps) and the jacchus group (C geoffroyi, C jacchus, C kuhlii, and C penicillata), this relatively young primate radiation is endemic to the Brazilian Cerrado, Caatinga, and Atlantic Forest biomes. Significant impacts on Callithrix within these biomes resulting from anthropogenic activity include (1) population declines, particularly for the aurita group; (2) widespread geographic displacement, biological invasions, and range expansions of C jacchus and C penicillata; (3) anthropogenic hybridization; and (4) epizootic Yellow Fever and Zika viral outbreaks. A number of Brazilian legal and conservation initiatives are now in place to protect the threatened aurita group and increase research about them. Due to their small size and rapid life history, marmosets are prized biomedical models. As a result, there are increasingly sophisticated genomic Callithrix resources available and burgeoning marmoset functional, immuno-, and epigenomic research. In both the laboratory and the wild, marmosets have given us insight into cognition, social group dynamics, human disease, and pregnancy. Callithrix jacchus and C penicillata are emerging neotropical primate models for arbovirus disease, including Dengue and Zika. Wild marmoset populations are helping us understand sylvatic transmission and human spillover of Zika and Yellow Fever viruses. All of these factors are positioning marmosets as preeminent models to facilitate understanding of facets of evolution, hybridization, conservation, human disease, and emerging infectious diseases.

Visual areas V1, V2 and MT (V5) were identified through myeloarchitectonic criteria and their sizes estimated in a flattened map of caudal cerebral cortex in the marmoset Callithrix penicillata. The ratio MT/V1 in this species is similar to values reported for other species of primates, but the ratio V2/V1 in Callithrix penicillata is smaller than that in macaques and larger than that in Aotus. The possible implications of these results are discussed.

We provide here a current overview of marmoset (Callithrix) evolution, hybridization, species biology, basic/biomedical research, and conservation initiatives. Composed of two subgroups, the aurita group (C. aurita and C. flaviceps) and the jacchus group (C. geoffroyi, C. jacchus, C. kuhlii and C. penicillata), this relatively young primate radiation is endemic to the Brazilian Cerrado, Caatinga, and Atlantic Forest biomes. Significant impacts on Callithrix within these biomes resulting from anthropogenic activity include: (1) population declines, particularly for the aurita group; (2) widespread geographic displacement, biological invasions, and range expansions of C. jacchus and C. penicillata; (3) anthropogenic hybridization; and (4) epizootic Yellow Fever and Zika viral outbreaks. A number of Brazilian legal and conservation initiatives are now in place to protect the threatened aurita group and increase research about them. Due to their small size and rapid life history, marmosets are prized biomedical models. As a result, there are increasingly sophisticated genomic Callithrix resources available and burgeoning marmoset functional, immuno-, and epi- genomic research. In both the laboratory and the wild, marmosets have given us insight into cognition, social group dynamics, human disease, and pregnancy. Callithrix jacchus and C. penicillata are emerging Neotropical primate models for arbovirus disease, including Dengue and Zika. Wild marmoset populations are helping us understand sylvatic transmission and human spillover of Zika and Yellow Fever viruses. All of these factors are positioning marmosets as preeminent models to facilitate understanding of facets of evolution, hybridization, conservation, human disease, and emerging infectious diseases.

0Microbiome studies show that host taxon, diet, and environment influence gut bacteria. 1However, these factors are rarely studied in animal hybrids and exudivores (which 4 2 nutritionally exploit indigestible oligosaccharides). To investigate the effects of host 4 3 taxon, hybridization, and environment on gut microbiota, we conducted 16S V4 4 4