Phylogeographic analyses of Callicebus lugens (Platyrrhini, Primates)

A phylogeographic study of Callicebus lugens was carried out based on cytochrome b DNA sequence data. Here, we report, for the first time, the distribution of C. lugens south of the Rio Negro, in Barcelos municipality (Amazonas State, Brazil), indicating that this river is not the southern boundary of the distribution of this species as previously proposed. Specimens from the north and south banks showed the same diploid number (2n = 16), while phylogenetic reconstructions based on maximum parsimony, distance, and maximum likelihood analyses grouped all specimens in a strongly supported clade comprising 2 separate lineages, in coincidence with their geographic distribution along riverbanks. Median-joining analysis showed a similar separation, with 22 transitions between the 2 groups, whereas time of divergence estimates indicated that the splitting of the C. lugens lineages occurred some 2.2 million years before present. Conservation strategies should take into consideration that this species might be sympatric with Callicebus torquatus at the south bank of Rio Negro.     

SRY evolution in Cebidae (Platyrrhini: Primates)

Sex determination in mammals is dependent on the presence of SRY, which codes for a protein with a DNA binding motif (the HMG-box domain). Here we analyze the evolution of SRY among seven genera of New World monkeys belonging to the family Cebidae. Estimates of the number of synonymous and nonsynonymous substitutions indicated the absence of positive selection acting on SRY evolution. The presence of indels at the C-terminus coding region in different genera and species maintained an open reading frame, indicating a selective pressure constraining the evolution of this coding region. Available data on the fertility of natural and captive interspecific hybrids failed to show any relationship between SRY evolution and speciation for the genera herein studied. Our phylogenetic arrangement for Cebidae genera was similar to previous topologies based on mitochondrial and autosomal DNA sequences. This arrangement also corroborated the division of Cebus into two species groups. However, for Callithrix the differences among SRY topology and those derived from autosomal and mitochondrial genes suggested a Y-chromosome ancestral polymorphism.     

Extensive Genetic Polymorphism of Peptidases A, B, C, and D, in Wild Rabbit (Oryctolagus cuniculus) Populations from the Iberian Peninsula

Genetic polymorphism of peptidases A, B, C, andD in the wild rabbit (Oryctolagus cuniculus)was assessed by horizontal starch gel electrophoresis,in a total of 1003 individuals comprising 16 Iberian and 2 French populations and 1 domestic stock.Twenty-five different alleles were detected: 6 in PEPA,4 in PEPB, 8 in PEPC, and 7 in PEPD. The highest valuesof observed heterozygosity averaged over the four loci were obtained for the southwestern Iberianpopulations and a clinal loss of variability in anortheastern direction was detected. A clear separationbetween the two putative subspecies O. c.cuniculus and O. c. algirus was notobtained.     

Chromosomal similarities and differences between tamarins,Leontopithecusand Saguinus (Platyrrhini,Primates)

The karyotypes of two taxa of genus Leontopithecus(rosalia and chrysomelas) are studied. Their G-, C- and NOR-banding patterns are compared with those of representatives of the genus Saguinus to determine chromosomal similarities and differences between the two genera and thus contribute to explaining phylogenetic relations between the tamarins. Leontopithecus, like the Saguinus, presents 2n = 46, 14 autosomes plus the Y acrocentric and 30 autosomes plus the X biarmed. No chromosomal rearrangement distinguishes the karyotypes of the representatives of genus Leontopithecus or genus Saguinus. The two genera are distinguished from each other by a paracentric inversion and pericentric inversions on at least four pairs of acrocentric autosomes, displacing the NORs of the small short arms in Leontopithecus to the proximal region of the long arms in Saguinus or vice versa. The tamarins are also distinguished by the distribution of noncentromeric constitutive heterochromatin. The data obtained indicate that the two tamarin genera are closely related chromosomally, suggesting that they probably originated from the same ancestral branch. Am. J. Primatol. 43:265–276, 1997. © 1997 Wiley-Liss, Inc.     

Comparative karyology and evolution of the Amazonian Callithrix (Platyrrhini,Primates)

Chromosomal studies in three species of Amazonian Callithrix (2n=44) and data in the literature show that this group is karyomonotypic. Moreover, it is characterized by the presence of abundant heterochromatic regions, unlike the situation in congeneric forms of Callithrix of the Atlantic coast with 2n=46, and by the presence of a highly repetitive, exclusive DNA component, with a basic repeat motif of 1528 bp. Karyotypic comparisons with other Callitrichids and an outgroup species showed that Callitrichids are karyologically conserved and explained several rearrangements that had presumably occurred during their phyletic radiation. Analyses of karyologic data enabled the construction of two alternative phylogenetic topologies. The lack of derived homoeologies, common to all members of the genus Callithrix grouped at present, and the fact that Amazonian species were more similar to Cebuella pygmaea (2n=44) than to their congeneric forms with 2n=46 suggested that species at present included in the Amazonian Callithrix should be grouped with C. pygmaea.     

Molecular cladistic markers in New World monkey phylogeny (Platyrrhini,Primates)

Transpositions of primate-specific Alu elements were applied as molecular cladistic markers in a phylogenetic analysis of South American primates. Seventy-four human and platyrrhine loci containing intronic Alu elements were PCR screened in various New World monkeys and the human outgroup to detect the presence of orthologous retrotransposons informative of New World monkey phylogeny. Six loci revealed size polymorphism in the amplification pattern, indicating a shared derived character state due to the presence of orthologous Alu elements confirmed by subsequent sequencing. Three markers corroborate (1) New World monkey monophyly and one marker supports each of the following callitrichine relationships: (2) Callithrix and Cebuella are more closely related to each other than to any other callitrichine, (3) the callitrichines form a monophyletic clade including Callimico, and (4) the next living relatives to the callitrichines are Cebus, Saimiri, and Aotus.     

Synteny of human chromosomes 14 and 15 in the platyrrhines (Primates, Platyrrhini)

In order to study the intra- and interspecific variability of the 14/15 association in Platyrrhini, we analyzed 15 species from 13 genera, including species that had not been described yet. The DNA libraries of human chromosomes 14 and 15 were hybridized to metaphases of Alouatta guariba clamitans, A. caraya, A. sara, Ateles paniscus chamek, Lagothrix lagothricha, Brachyteles arachnoides, Saguinus midas midas, Leontopithecus chrysomelas, Callimico goeldii, Callithrix sp., Cebus apella, Aotus nigriceps, Cacajao melanocephalus,Chiropotes satanas and Callicebus caligatus. The 14/15 hybridization pattern was present in 13 species, but not in Alouatta sara that showed a 14/15/14 pattern and Aotus nigriceps that showed a 15/14/15/14 pattern. In the majority of the species, the HSA 14 homologue retained synteny for the entire chromosome, whereas the HSA 15 homologue displayed fragmented segments. Within primates, the New World monkeys represent the taxon with the highest variability in chromosome number (2n = 16 to 62). The presence of the HSA 14/15 association in all species and subspecies studied herein confirms that this association is the ancestral condition for platyrrhines and that this association has been retained in most platyrrhines, despite the occurrence of extensive inter- and intrachromosomal rearrangements in this infraorder of Primates.     

Satellite DNA sequences in the neotropical marmoset Callimico goeldii (Primates,Platyrrhini)

Two families of tandemly repeated satellite DNAs were isolated from the neotropical primate Callimico goeldii (Goeldi's marmoset). One satellite, CgoA, is over 70% A+T and has a monomer length of 338 bp. The other satellite, CgoB, is 50% A+T and has a monomer length of 916 bp. Both CgoA and CgoB hybridize strongly with Callimico DNA, but not with the DNA of other new and old world primates. Based upon a neutral substitution rate of 1.5×10^–9/site per year for primates, sequence data from 15 CgoA monomers indicate that the tandem array is at least 30 million years old. Since no other neotropical primate has amplified CgoA sequences, the data suggest that the ancestor of Callimico separated from the other neotropical primates at least 30 million years ago. This value is about fourfold larger than the value of 7–9 million years derived from immunological data by Sarich and Cronin (1980). Possible reasons for this discrepancy are discussed. On leave from: Genetics Section, Instituto Nacional do Cancer, Rio de Janeiro/Department of Genetics, Universidade Federal do Rio de Janeiro, Brazil     

Molecular phylogenetics of large-bodied tamarins, Saguinus spp. (Primates, Platyrrhini)

With 33 recognized taxa, the tamarins, Saguinus spp., constitute the most diverse genus of New World monkeys (Platyrrhini), and are found almost exclusively within the Amazon basin. This diversity can be subdivided into three main morphological groups, based primarily on pelage characteristics, although there is also an ecologically important division between the small- and large-bodied forms (adult body weight ± 300 g vs. > 450 g, respectively). In the present study, the phylogenetic relationships among the large-bodied forms were analysed using the sequences of a fragment of the mitochondrial rRNA16S gene, from which 58 informative sites were identified. The analysis revealed the existence of four main lineages, three of which coincided with geographical and/or morphological patterns. However, Saguinus leucopus formed a highly distinct clade, contradicting expectations based on its morphology and distribution, but corroborating a previous study of the NADH dehydrogenase subunit I (ND1) gene. Whereas genetic differences between some closely related species were relatively small (< 1%), that observed between the two specimens of S. imperator was twice higher (± 2%), indicating the possible presence of distinct species within this taxon. Previous molecular clock analysis suggested that the earliest radiation event of the large-bodied tamarins occurred sometime in the lower Miocene, whereas the most recent events, such as the division of the closely related S. midas and S. niger would have occurred during the Pleistocene. Most of these events would thus have taken place before the formation of the present-day river system, which now constitutes a considerable barrier to gene flow among many populations.     

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.     

Satellite DNA sequences in the New World primateCebus apella (Platyrrhini,Primates)

Two satellite DNAs, designated CapA and CapB, were isolated from the neotropical primate,Cebus apella. The satellites exhibit nonoverlapping distributions onC. apella chromosomes. CapA is a major component of interstitial regions of constitutive heterochromatin, a very large block of heterochromatin comprising most of the long arm of chromosome 11, and some telomeres. The CapA monomer has a length of about 1500 bp and appears recently to have undergone an amplification episode in theC. apella genome. CapA-like sequences are probably present in members of the family Cebidae (to whichC. apella belongs), but not in members of the family Callitrichidae (marmosets). CapB sequences can be detected at the centromeres of manyC. apella chromosomes, and similar sequences are present in all neotropical primates. The 342 bp CapB monomer shares 60%–64% sequence identity with several alpha satellite sequences of human origin. Because of its structure, sequence, and location, it appears that CapB is the New World primate homolog of Old World primate alpha satellite DNA.     

ABO Blood groups in cebidae (Platyrrhini,Primates) from the Rio Jamari Region

Blood and saliva samples were collected from 84Aotus azarae boliviensis, 31Ateles paniscus chamek, 130Callicebus brunneus, 130Cebus apella, 117Pithecia irrorata irrorata, and 117Saimiri ustus. Saliva samples were investigated for human ABH antigens by the standard hemagglutination inhibition test. Two species,P. irrorata andC. brunneus showed monomorphism, presenting only the A blood group. Among the polymorphic species,A. paniscus andC. apella presented theO (30 and 3) and A (1 and 127) phenotypes, and the B (80) and AB (4) phenotypes were detected inA. azarae. S. ustus was the only species that presented all the four phenotypes. The observed distribution was as expected assuming Hardy-Weinberg equilibrium to be present in those species that could be tested. The ABH substances were titrated and a comparison among species was made. Serum samples were used to detect natural antibodies and the results showed some disagreement between serum and saliva phenotypes.     

Chromosomal localization of the telomeric (TTAGGG)n sequence in eight species of New World Primates (Neotropical Primates, Platyrrhini)

Chromosomal localization of the telomeric sequence (TTAGGG)(n) in eight New World Primates (Platyrrhini) (Alouatta caraya, Alouatta palliata, Alouatta guariba clamitans, Aotus azarae, Ateles chamek, Cebus nigritus, Cebus paraguayanus, and Saimiri boliviensis) using Fluorescence In Situ Hybridization (FISH) with a peptide nucleic acid (PNA) pantelomeric probe and their possible relationship with the C-banding pattern were analyzed. FISH showed telomeric signals only at the terminal regions of chromosomes from all the species analyzed. Although all of them showed centromeric C+ bands and different size and location of extracentromeric C+ bands, none, except Aotus azarae exhibited (peri)centromeric interstitial telomere-like sequences (ITS). The presence of ITS in Aotus azarae was limited to one pair of submetacentric chromosomes and very likely represents telomeric sequences remaining after a fusion event of ancestral chromosomes during karyotype evolution. Therefore, our data indicate that the distribution of heterochromatin blocks do not correlate with the presence of ITS. However, we cannot rule out the possibility that simple ITS arrays with a few copies of the (TTAGGG)(n) sequence, not detectable by conventional FISH, might play a role in the karyotypic evolution of Ceboidea. Further FISH and molecular studies will be needed to confirm this hypothesis.     

Taste areas of the plica sublingualis of Alouatta and Aotus (Primates,Platyrrhini)

A conspicuous accumulation of taste buds occurs in the rostral part of the plica sublingualis ("frenal lamella") of Alouatta and Aotus forming taste areas (area gustatoria) superficially situated in the oral mucous membrane. They are found in close vicinity to the orifices of the sublingual salivary glands, but are lacking in the aboral part of the plica sublingualis. They do not occur in all primate species studied. A taste area does not projects above the surface of the surrounding tissue like a papilla. The taste buds open not in crypts of furrows of the oral mucosa, but directly into the spatium sublinguale of the oral cavity proper. In the anterior part of the cavum oris proprium different kinds and very differentiated qualities of sensoral information are perceived (touch, olfaction, temperature). It is conceivable that the taste areas play an important role in perceiving fresh saliva, together with the other sensorial structures in this part of the mouth. This problem can be solved experimentally and by behavioral studies, In addition to its topographical relation to the tongue, the organon sublinguale of Callicebus is structurally very similar to the plica sublingualis of Aotus and Alouatta. Since a sublingua does not occur in New World monkeys, it can be concluded that this organ represents a plica sublingualis which became adherent to the undersurface of the tongue.     

Molecular Variation in AVP and AVPR1a in New World Monkeys (Primates,Platyrrhini): Evolution and Implications for Social Monogamy

The neurohypophysial hormone arginine vasopressin (AVP) plays important roles in fluid regulation and vascular resistance. Differences in AVP receptor expression, particularly mediated through variation in the noncoding promoter region of the primary receptor for AVP (AVPR1a), may play a role in social phenotypes, particularly social monogamy, in rodents and humans. Among primates, social monogamy is rare, but is common among New World monkeys (NWM). AVP is a nonapeptide and generally conserved among eutherian mammals, although a recent paper demonstrated that some NWM species possess a novel form of the related neuropeptide hormone, oxytocin. We therefore characterized variation in the AVP and AVPR1a genes in 22 species representing every genus in the three major platyrrhine families (Cebidae, Atelidae and Pitheciidae). For AVP, a total of 16 synonymous substitutions were detected in 15 NWM species. No non-synonymous substitutions were noted, hence, AVP is conserved in NWM. By contrast, relative to the human AVPR1a, 66 predicted amino acids (AA) substitutions were identified in NWM. The AVPR1a N-terminus (ligand binding domain), third intracellular (G-protein binding domain), and C-terminus were variable among species. Complex evolution of AVPR1a is also apparent in NWM. A molecular phylogenetic tree inferred from AVPR1a coding sequences revealed some consensus taxonomic separation by families, but also a mixed group composed of genera from all three families. The overall dN/dS ratio of AVPR1a was 0.11, but signals of positive selection in distinct AVPR1a regions were observed, including the N-terminus, in which we identified six potential positive selection sites. AA substitutions at positions 241, 319, 399 and 409 occurred uniquely in marmosets and tamarins. Our results enhance the appreciation of genetic diversity in the mammalian AVP/AVPR1a system, and set the stage for molecular modeling of the neurohypophyseal hormones and social behavior in primates.     

Ontogeny and homology of the paranasal sinuses in Platyrrhini (Mammalia: Primates)

The identity and taxonomic distribution of paranasal sinuses among living platyrrhines has remained a contentious issue (e.g., Cave [1967] Am J Phys Anthropol 26:277-288 vs. Hershkovitz [1977] Chicago: University of Chicago Press) largely because the ontogenetic data required for their detection and identification (e.g., Cave [1967]; Maier [2000] Cambridge, UK: Cambridge University Press, 99-132.) were not attainable without sacrificing valuable juvenile and subadult specimens. Non-invasive computed tomography (CT) scanning of ontogenetic series of skulls for 10 platyrrhine genera demonstrates the presence of maxillary and ethmoid sinuses, as well as homologs of the human sphenoid and frontal sinuses. Differences in the latter two sinuses between platyrrhines and hominoids highlight the need for early developmental data in establishing sinus homology. In particular, the identification of homologous recesses in the cartilaginous nasal capsule, from which sinuses later develop, emerges as the critical step. This developmental approach also reveals that the anterior and posterior ethmoid sinuses are each sets of serial homologs, a point which reconciles previous difficulties in establishing sinus homologies across mammalian orders (e.g., Paulli [1900] Gegenbaurs Morphol Jahrb 28:147-178, 179-251, 483-564).     

A mandible ofBranisella boliviana (Platyrrhini,Primates) from the oligocene of South America

A mandibular specimen from the Bolivian Early Oligocene is provisionally assigned toBranisella boliviana. The crown anatomy of the single preserved tooth, an M₂, indicates platyrrhine affinities and several details of the broken jaw are suggestive of symphyseal fusion. Like the African Oligocene parapithecids,Branisella contrasts with extant anthropoids in the relative shallowness of its mandible.Branisella is the most ancient, and seemingly the most primitive, fossil platyrrhine monkey, lacking any of the derived features of the two major clades of modern ceboids. Taxonomically, it is best regarded as family incertae sedis.     

Evolution of the SEC1 gene in New World monkey lineages (Primates, Platyrrhini)

The structure and evolution of the SEC1 gene were examined for the first time in New World primates of the genera Alouatta, Aotus, Ateles, Brachyteles, Callicebus, Callithrix, Cebus, Chiropotes, Lagothrix, Leontopithecus, Pithecia, Saguinus, and Saimiri. This gene has a high CG content (63.8%) and an estimated heterogeneous size ranging from 795 (Callithrix) to 1041 bp (Pithecia), due to numerous indel events. Similar to other fucosyltransferases, three conserved regions are shared by these primates, except for the callitrichines, Aotus and Pithecia, in which indel events resulted in premature stop codons that are related to the production of a supposedly non-functional protein. Phylogenetic analysis of the SEC1 gene, transition/transversion rates, and nucleotide sequence alignment support the hypothesis that primate SEC1 evolved by divergent evolution, and that the lack of activity in some lineages occurred independently at least twice in New World primates, once in the Aotus-Cebus-Callitrichinae group and again in Pithecia. Likelihood-based inference of ancestral states for the activity of SEC1 leads us to suppose that inactivation of SEC1 in the Callitrichinae was a result of a more complex series of events than in Pithecia.     

Intra and Interspecific Variation in Cranial Morphology on the Southernmost Distributed Cebus (Platyrrhini,Primates) Species

Capuchin monkeys (Cebus) are one of the genera with the widest distribution among Neotropical primates (New World Monkeys, Platyrrhini), accompanied by an elevated genetic, phenotypic, behavioral, morphological, and ecological diversity, both at the interspecific and population levels. Despite being one of the most studied primate genera, this high diversity has led to a particularly complex and controversial taxonomy. In this contribution, we explored the patterns of skull size and shape variation among the southernmost distributed populations of Cebus using three-dimensional geometric morphometric techniques. Results showed a marked morphological differentiation (in size and shape) between previously recognized species (C. nigritus and southern C. libidinosus), and also among C. libidinosus populations, which were quantitatively related with the geographic distance between them. This pattern supports a differentiation between the northwestern Argentina and southern Bolivia and Paraguay forms. Other taxonomic implications are also discussed.     

The Callimico goeldii (Primates,Platyrrhini) genome: Karyology and middle repetitive (LINE-1) DNA sequences

Callimico goeldii (Goeldi's marmoset) is a neotropical primate with 2n=47,X1X2Y in the male, and 2n=48,X1X1X2X2 in the female, due to a Y-autosome translocation. Karyological comparisons of Callimico, Callithrix jacchus and Cebus apella suggest that Callimico is a member of the Callitrichidae. Isozyme data and restriction mapping of LINE-1 repetitive elements in these species and in a variety of other neotropical primates confirm these findings and supply strong evidence for including Callimico in the Callitrichidae. On leave from: Genetics Section, Instituto Nacional do Cancer (Rio de Janeiro)/Department of Genetics, Universidade Federal do Rio de Janeiro, Brazil