Proposed chromosomal phylogeny for the South American primates of the Callitrichidae family (Platyrrhini)

Cytogenetic and cytotaxonomic studies (G, C, sequential G/C, and NOR banding) were performed on 110 specimens representing the four genera of South American primates of the family Callitrichidae: Cebuella (C. pygmaea), Callithrix, groups argentata (C. argentata, C. emiliae, C. chrysoleuca, C. humeralifera, C. mauesi), and jacchus (C. aurita, C. geoffroyi, C. jacchus, C. kuhli, C. penicillata), Leontopithecus (L. chrysomelas, L. rosalia), and Saguinus (S. midas midas, S. m. niger). Mitotic chromosomes are characterized, and the rearrangements distinguishing the karyotypes of the taxa are inferred from arm homologies. The results were then converted into numerical data and submitted to cladistic analysis. The following conclusions were achieved: 1) Five karyotypic classes were observed, which correspond to the five taxa studied. Differences between them are as follows: a) Cebuella (2n = 44, 10 acrocentrics, A + 32 bi‐armed autosomes, bi) and the argentata group (2n = 44, 10A + 32bi) are different from each other due to a reciprocal translocation; b) both can be distinguished from the jacchus group (2n = 46, 14A + 30bi) by a centric fusion/fission rearrangement and a paracentric inversion; c) Leontopithecus (2n = 46, 14A + 30bi) and Saguinus (2n = 46, 14A + 30bi) differ from the jacchus group by a reciprocal translocation and three paracentric inversions; and d) Saguinus is different from the others by one paracentric inversion and pericentric inversions in at least four pairs of acrocentric autosomes. 2) The cladistic analysis separates Cebus (used as an outgroup) from the Callitrichidae groups, which forms a clade. Among the Callitrichidae, marmosets (Cebuella and Callithrix) form a sub‐clade, Cebuella and the argentata group being more closely related to each other than both are to the jacchus group. Tamarins (Leontopithecus and Saguinus) are also quite close, so that if one was not derived from the other, they with the marmosets share a common ancestor. Among the tamarins, Leontopithecus is karyotypically closest to the marmosets, specifically to the jacchus group. 3) Based on the chromosome information and considering the possible direction of the evolutionary changes (primitivity or phyletic dwarfism hypothesis, previously advanced by other authors), it was possible to propose the ancestral karyotypes and to develop two alternatives for the origin, differentiation and dispersion of the callitrichid. Both proposals are plausible, but when the geographical distribution is considered, the phyletic dwarfism hypothesis seems to be the most probable. Am. J. Primatol. 49:133–152, 1999. © 1999 Wiley‐Liss, Inc.     

Phylogenetic relationships of vespertilionid genera (Mammalia: Chiroptera) as revealed by karyological analysis

Banded karyotypes of 50 species belonging to 23 genera were analyzed. The diploid chromosome numbers ranged from 26 to 50. For karyotypic comparison we used a 44 chromosomes karyotype, consisting of 4 metacentric and 17 acrocentric autosomes, as “basic karyotype”. Almost all of its 25 autosomal arms could be identified in each individual karyotype. In 8 chromosomes, i. e. 1/2, 7, 11, 12, 13, 15, 23 and X, small inversions were detected. As a result, each of the chromosomes mentioned occurs in two states which differ slightly in their banding patterns. These were used as character states in the cladistic analysis together with other chromosomal rearrangements. The implications drawn from the cladogram obtained are: The Miniopterinae clearly belong to the Vespertilionidae but are the first to branch off from the common stem. The tribe Myotini should be raised to the rank of a subfamily. Within the largest subfamily Vespertilioninae, one autapomorphic chromosomal character was found for each of the tribes Vespertilionini and Pipistrellini. In addition, both tribes are distinguished from the other Vespertilioninae tribes by two synapomorphic features. These results allow for the first time an unequivocal classification of the systematically difficult “pipistrelloid” species. The species of the genus Pipistrellus (sensu Hill and Harrison 1987) are spread over the Pipistrelllni and Vespertilionini. We therefore suggest the splitting of this heterogenous genus into at least four genera. Only the members of the previous subgenus Pipistrellus constitute the genus Pipistrellus and belong to the Pipistrellini. The previous subgenera Hypsugo, Vespadelus and Falsistrellus, given generic rank in some recent studies, belong to the tribe Vespertilionini and are not closely related to Pipistrellus. For the genera Eptesicus and Hesperoptenus, which belong neither to the Vespertilionini nor to the Pipistrellini, the tribe Eptesicini was established. The phylogenetic relations of this tribe and the status of the presumably polyphyletic tribe “Nycticeiini” could not be solved.     

Sequences of dental ontogeny and callitrichid taxonomy

Sequences of dental development and eruption radiographically determined for 160 immature callitrichids were combined with nonontogenetic criteria in an investigation of callitrichid affinities. Marmosets (Callithrix andCebuella) are distinct from tamarins (Leontopithecus andSaguinus) in both sequences of dental ontogeny and nonontogenetic characters.Callimico presents a tamarin-like pattern in its dental ontogeny and overall appearance. A new callitrichid classification which separates marmosets and tamarins into different subfamilies (Callitrichinae, Leontopithecinae and Callimiconinae) is proposed. Dental ontogenetic data suggest that callitrichids are derived platyrrhine taxa.     

Banded karyotypes of mole rats (Spalax, Spalacidae, Rodentia) from Turkey: a comparative analysis

Chromosome banding (G-, C- and Ag-NOR) analysis was carried out on 27 specimens of Sphalax ehrenbergi from seven localities and two specimens of S. leucodon from one locality, all from Turkey. No chromosomal variation was detected in S. ehrenbergi populations from Elazig, Siverek, Diyarbakir and Birecik having the same diploid numbers (2n = 52) and morphology of chromosomes (NFa = 72). The karyotypes of mole rats from Tarsus and Gaziantep possessed the identical diploid number (2n = 56) but different numbers of autosomal arms: NFa = 68 in the Tarsus and NFa = 78 in the Gaziantep populations. Chromosomes of S. leucodon from Malaty (2n = 60, NFa = 74) differed distinctly in the C-banding pattern from all S. ehrenbergi cytotypes by the almost entire absence of heterochromatin in acrocentric autosomes and the presence of heterochromatin arms iin subtelocentric autosomes. Nucleolar organizing regions were found mainly on three pairs of chromosomes, but some differences in their localization were revealed. Comparison of G-banded chromosomes showed, that most chromosomes have a similar pattern. The types of chromosomal rearrangemetns were revealed due to the banding methods.     

Chromosomes and evolution of the ground squirrel,Spermophilus richardsonii

Summary Chromosomes were analyzed from two geographically isolated populations of Spermophilus richardsonii. The diploid chromosome number was 36 in S. r. richardonii (Montana population) and 34 in S. r. elegans (Wyoming-Colorado population). The richardsonii Karyotype differed from elegans by the presence of two pairs of acrocentric autosomes whereas the elegans Karyotype lacked acrocentric autosomes and had an extra pair of submetacentrics.A chromosomal polymorphism, produced by centric fusion, probably existed in the more primitive richardsonii population. After ancestral stock of the elegans population became geographically isolated, both populations of S. richardsonii evolved independently and developed different karyotypes derived from the original polymorphism. Although the karyotypes have evolved to a stage found in valid species, the populations may not have been separated long enough to attain reproductive isolation.This investigation was supported by a grant from the National Science Foundation (GB-503).     

Phylogenetic relationships of the callitrichinae (Platyrrhini,Primates) based on β2‐microglobulin DNA sequences

The phylogenetic relationships of callitrichine primates have been determined by DNA sequence analyses of exons 1, 2, and 3 of the β₂‐microglobulin gene. Parsimony, distance, and maximum likelihood analyses of ca. 900 base pairs of 21 taxa, representing all callitrichine genera, indicated that Saguinus was the most basal offshoot. Within Saguinus, S. fuscicollis appeared as the first divergent lineage followed by an unresolved trichotomy formed by S. mystax/S. imperator, S. midas/S. bicolor, and S. oedipus. A second callitrichine lineage was formed by Leontopithecus; each of the three species studied showed identical nucleotide sequences. Callimico appeared as the sister taxon of Callithrix/Cebuella. Genetic distances within this latter group were very small, although a stronger association between Cebuella and species of the Callithrix argentata group was observed. The inclusion of Cebuella in the genus Callithrix is suggested. These studies indicated that tamarins are more plesiomorphic than marmosets in agreement with the phyletic dwarfism hypothesis. Am. J. Primatol. 48:225–236, 1999. © 1999 Wiley‐Liss, Inc.     

Historical biogeography of tamarins,genus Saguinus: the molecular phylogenetic evidence

Hypotheses of the historical biogeography of tamarins (genus Saguinus) based on variation in coat colors and body size are tested using phylogenetic relationships inferred from mitochondrial DNA (mtDNA) sequence data. Samples from all 12 species of Saguinus and several subspecies are included in the analysis. Approximately 1,200 bases of mtDNA sequence from the cytochrome b and D-loop regions are reported for the tamarins and several outgroup taxa. Parsimony analysis of the mtDNA sequence data reveals Saguinus to be a monophyletic taxon composed of two major clades: one, the Small-bodied clade, contains S. nigricollis, S. tripartitus, and S. fuscicollis, and the other, the Large-bodied clade, contains the other nine species. The phylogenetic relationships among tamarins inferred from the mtDNA sequence data reject previous hypotheses for the historical biogeography of tamarins and suggest different dispersal routes for this group of New World monkeys. The molecular data suggest that tamarins dispersed across South America in two major waves from an origin somewhere south of the Amazon. One wave moved in a westerly direction, whereas the other moved in a northeastern direction toward the Amazon delta and then west along the northern portion of the continent into northern Colombia and Panama. Am J Phys Anthropol 108:65–89, 1999. © 1999 Wiley-Liss, Inc.     

Neophilia, innovation and social learning: a study of intergeneric differences in callitrichid monkeys

In a comparative study of neophilia, innovation and social attentiveness we exposed individuals in seven callitrichid species, from three genera, to novel extractive foraging tasks. The results revealed consistently shorter response latencies, higher levels of successful and unsuccessful manipulation, and greater attentiveness to the task and to conspecifics inLeontopithecus (lion tamarins) than in both Saguinus (tamarins) and Callithrix (marmosets). This is consistent with the hypothesis that species dependent upon manipulative and explorative foraging tend to be less neophobic and more innovative than other species. Furthermore, Callithrix appeared to be less neophobic than Saguinus; ifCallithrix is regarded as the greater specialist, this result is inconsistent with the hypothesis that neophobia is associated with foraging specialization. We consider the relevance of our findings to taxonomic relationships, and to technical and Machiavellian intelligence hypotheses and discuss the implications for captive breeding and reintroduction strategies.Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.      

A Reexamination of the Phylogenetic Position of Callimico (Primates) Incorporating New Mitochondrial DNA Sequence Data

The New World monkeys are divided into two main groups, Callitrichidae and Cebidae. Callimico goeldii shares traits with both the Cebidae and the Callitrichidae. Recent morphological phyletic studies generally place Callimico as the most basal member of the Callitrichidae. In contrast, genetic studies (immunological, restriction fragment, and sequence data) have consistently placed Callimico somewhere within the Callitrichidae, not basal to this clade. A DNA sequence data set from the terminal 236 codons of the mitochondrial ND4 gene and the tRNA^His, tRNA^Ser, and tRNA^Leu genes was generated to clarify the position of Callimico. The sequences of 887 base pairs were analyzed by maximum-parsimony, neighbor-joining, and maximum-likelihood methods. The results of these various methods are generally congruent and place Callimico within the Callitrichidae between the marmosets (Callithrix and Cebuella) and the tamarins (Saguinus and Leontopithecus). Combined analyses of all suitable nuclear and mitochondrial gene sequences confirm the position of Callimico between the marmosets and the tamarins. As available molecular evidence indicates that Callimico is more closely related to the marmosets than to the tamarins, a reconsideration of the morphological evidence in light of the consensus tree from DNA sequence analyses is warranted. The marmosets and tamarins share four morphological characters (loss of the third molar, loss of the hypocone, reduced body size, reproductive twinning). Dwarfism may have evolved repeatedly among the Callitrichidae. It is well-known that the loss of a character can occur many times independently. The reproduction of marmosets and tamarins is extremely specialized and it is difficult to imagine that this complex and unique twinning system evolved separately in marmosets and tamarins. However, it is possible that a secondary reversal to single offspring took place in Callimico. Received: 20 March 1997 / Accepted: 17 December 1997     

Chromosomal diversification of reef fishes from genus <Emphasis Type="Italic">Centropyge</Emphasis>(Perciformes,Pomacanthidae)

The genus Centropyge is remarkable for species richness, composing a highly specialized fish group amongst members from family Pomacanthidae. However, cytogenetical reports are nearly absent in these animals. New data are provided from karyotypical studies carried out on Centropyge aurantonotus from the Brazilian coast of the Atlantic Ocean and C. ferrugatus from the Philippines Sea of the Indo-Pacific Ocean. Both species present 2n=48 but karyotypes are differentiated by fundamental number. C. aurantonotus has a great number of biarmed chromosomes (4 m + 14 sm+16 st+4 a), while C. ferrugatus presents only acrocentric chromosomes. Single nucleolar organizer regions (NORs) are located at interstitial position of an acrocentric pair in C. ferrugatus and on short arms of a subtelocentric pair in C. aurantonotus, as confirmed by fluorescent in situ hybridization (FISH) with 18S rDNA probes. Heterochromatin is distributed over NOR and centromeric regions in both species, but additional GC-rich heterochromatic blocks on short arms of up to eight chromosomal pairs can be detected in C. aurantonotus. 5S rDNA segments were located interstitially on two chromosomal pairs in C. ferrugatus and on nine pairs in C. aurantonotus, mostly equivalent to heterochromatic blocks on short arms of biarmed chromosomes. C. ferrugatus can be considered a species in which basal chromosomal features proposed for modern Teleosteans were conserved. The derived karyotype pattern of C. aurantonotus seems to be determined by pericentric inversions and heterochromatin addition which probably determined the notorious dispersion of 5S rRNA (pseudo)genes. It is demonstrated that, even within a group generally characterized by cytogenetical homogeneity as the family Pomacanthidae, diversified karyotypes can be found.     

Constitutive heterochromatin,G-bands and nucleolus-organizer regions in four species of Didelphidae (Marsupialia)

Chromosomes of Didelphis albiventris, D. marsupialis, Philander opossum and Lutreolina crassicaudata, four species of marsupials with very similar karyotypes and 2n=22 were studied. All the chromosomes were acrocentrics except the X in L. crassicaudata, which is a metacentric.The G-band patterns of these species are similar but the distribution of constitutive heterochromatin differs among them as shown by C-banding. The hypothesis that the X in L. crassicaudata might be an isochromosome derived from the acrocentric X in the other species is discarded since G-and C-banding patterns differ in the two arms.In D. marsupialis the Ag-NORs are terminal and located in both arms of one pair and in the long arms of two pairs of medium-sized autosomes. In P. opossum the NOR-bearing chromosomes could be precisely identified through simultaneous silver staining and G-banding. The Ag-NORs are terminal and located at the short arm of pair 5 and the long arm of pair 7.     

Ovarian function of pygmy marmoset daughters (Cebuella pygmaea) in intact and motherless families

Reproductive inhibition of subordinate Callitrichid group members has been shown to vary with genus; whereas female Leontopithecus subordinates have normal ovarian cycles and occasionally breed within groups, subordinate Saguinus females almost never do so, with Callithrix species showing intermediate levels of reproductive inhibition. No information has been available on patterns of reproduction or inhibition in subordinate females in the genus Cebuella. We assessed fertility in Cebuella pygmaea daughters to allow comparison with the remaining Callitrichid genera. Specifically, the project had two goals: 1) to determine if there was evidence of reproductive inhibition of daughters living in family groups, and 2) to compare the ovarian function of daughters living in intact family groups with that of daughters residing in motherless families (i.e., without the breeding female). We collected daily urine samples for 6–8 weeks from eight pygmy marmoset daughters living in intact family groups or motherless families. Determination of ovulatory cycling or reproductive quiescence depended on the hormonal profiles generated from urinary luteinizing hormone and pregnanediol-3-glucuronide concentrations. All females in the motherless condition (aged 13–30 months) (n = 4) ovulated during the study. In contrast, only one of four daughters (aged 13–20 months) residing in intact families was found to be cycling. Data from motherless groups indicate ovarian cycling may begin between 15 and 17 months of age. Reproductive inhibition occurs in pygmy marmosets, although in a pattern more similar to Callithrix than to other Callitrichid genera. Am. J. Primatol. 43:347–355, 1997. © 1997 Wiley-Liss, Inc.     

Chromosomal variation in social voles: a Robertsonian fusion in Günther’s vole

The study reports on chromosomes in several populations of social voles from south-eastern Europe and the Middle East. The standard karyotypes of individuals of Microtus hartingi and Microtus guentheri originating from both south-eastern Europe and Asia Minor comprised 54 mostly acrocentric chromosomes. However, variation between populations was found in the amount and distribution of C-heterochromatin in certain autosomes and the sex chromosomes. Furthermore, a specific pattern of argyrophilic nucleolar organizer region distribution was recorded in different geographic populations. In a population from Asia Minor, a heterozygous centric fusion of two autosomes was found. The G-banded karyotypes of M. guentheri and Microtus socialis were compared, and tandem fusions of autosomes were suggested as possible mechanism of the divergence. The karyotypes of the nine currently recognized species of social voles are reviewed, and implications of chromosomal data for systematics are evaluated.     

KARYOTYPIC DATA ON NORTH AND CENTRAL AMERICAN ZAMIACEAE (CYCADALES) AND THEIR PHYLOGENETIC IMPLICATIONS

Chromosome numbers and karyotypes of species from four American Zamiaceae (Cycadales) are reported. Zamia shows interspecific and intraspecific chromosome variation, whereas Microcycas, Ceratozamia, and Dioon have constant karyotypes within each genus. In Zamia, all karyotypes have the same number of submetacentric and acrocentric chromosomes, but they differ in the number of metacentric and telocentric chromosomes. Centric fission of metacentric chromosomes is proposed to explain the karyotypic variation in this genus. Zamia shows karyological relationships with Microcycas and Ceratozamia, whereas Dioon appears very distinct from the other American cycad genera. Affinity among Zamia, Ceratozamia, and Microcycas karyotypes and distinctiveness of Dioon karyotypes are supported by comparative analysis of phenotypic characters in the four genera.     

Callitrichids as phyletic dwarfs,and the place of the callitrichidae in platyrrhini

Cebuella, Callithrix, Leontopithecus, andSaguinus share five distinguishing features. All of these features are best interpreted as derived character states within Platyrrhini, and these animals are phyletic dwarfs. These derived traits may form a single complex that evolved as a result of dwarfing. Two changes in the dentition are shown to be correlated with dwarfing in mammals. These four platyrrhine genera may or may not form a monophyletic group. It is suggested thatCallimico is an “incipient dwarf platyrrhine.” Causes of dwarfing in mammals are discussed.     

Chromosomes of Syrphidae

This report describes the karyotypes of fourteen species of the tribe Chrysotoxini (Diptera, Syrphidae) with the single genus Chrysotoxum. The species are listed in the Table on p. 240. All have 2n=10 chromosomes, usually consisting of short apparently telocentric sex chromosomes plus two subtelocentric and two submetacentric pairs of autosomes.     

鹿科动物的染色体组型及其进化

染色体是遗传物质的主要携带者。在动植物进化过程中,染色体在数量和结构上的变化,无疑对物种形成起重要的作用。染色体的变化往往引起基因的重新排列和遗传物质的增加或丢失。染色体在结构和数量上的差异还往往造成两个本来很相近的群体间的生殖隔离而形成新种。染色体组型和染色体的带型都代表着种的特性,它为不同动物在分类研究和确定其在进化过程中的位置提供了一个新的和重要的标准。可是,染色体的结构既是稳定的,同时又是可变的。染色体组型的改变是以染色体组的结构特点为基础     

Habitat and the evolution of social and reproductive behavior in callitrichidae

The numerous remarkable traits characterizing the ecology and behavior of callitrichids have inspired considerable research and discussion of the flexible mating system (cases of monogamy, polygyny, and polyandry), cooperative breeding, reproductive inhibition by dominant females, rapid reproductive rate, significance of dietary differences (gum feeding, frugivory, and insectivory), and demographics and social characteristics of the four genera, Cebuella, Callithrix, Saguinus, and Leontopithecus. The majority of functional explanations evaluate costs, benefits, and alternative strategies but do not address the critical selective forces that led to the behaviors in the first place. In this paper, it is argued that Callithrix and Saguinus evolved to occupy a small insectivore/frugivore niche in secondary growth forest patches (gaps arising from tree falls), and other successional forests and edge habitats; that Cebuella evolved to occupy a gum-feeding/insectivore niche in inundated forest; and that Leontopithecus is above all a small animal predator/frugivore and a mature forest genus. The keys to explanations concerning the evolution of the social and reproductive systems of these animals lie in an understanding of the resource base in these different habitats. Finally, it should be remembered that studies of callitrichids have in the main part been carried out in habitats highly altered by human activities (especially the Brazilian Atlantic forest, home to marmosets and lion tamarins) and are not the environments in which their social and breeding behavior evolved. © 1996 Wiley-Liss, Inc.     

Structural patterns of enamel in the superfamily Ceboidea

A fundamental enamel structure was found in the superfamily Ceboidea, and tentatively named the nonserial pattern, as distinguished from the multiserial and uniserial patterns. In the nonserial pattern, almost all rows of enamel prisms are straight to slightly curved from the enameldentin junction to the surface of the tooth, and are nearly uniformly oriented. Accordingly, Schreger's band is definitely lacking throughout the length and width of enamel. The interprismatic bundles between both adjacent rows are well developed. The nonserial pattern has so far been found to be limited to some genera of which the molars preserve rather primitive external features; i.e.,Saimiri, Callicebus, Aotus, Alouatta, Saguinus andLeontopithecus. On the other hand, the multiserial pattern is fairly common in many genera of the Ceboidea. The nonserial pattern, which corresponds to the pattern I described byBoyde (1964), is the most primitive, judging from its occurrence, structural simplicity and other factors. The multiserial and uniserial patterns are assumed to be independently evolved from the nonserial pattern.     

Phenotypic,Genetic, and Cytogenetic Evidence of Hybridization Between Species of Trans-Andean Tamarins (Genus <Emphasis Type="Italic">Saguinus</Emphasis>)

Incomplete reproductive isolation and hybridization is relatively frequent in primates. However, no cases of hybridization between formally recognized species have been reported in tamarins (genus Saguinus), a highly specious group of Neotropical primates. Here, we provide evidence from different sources to demonstrate three cases of hybridization in captivity between species of Saguinus distributed west of the Andes (trans-Andean). To do this, we described fur color patterns, genotyped 12 microsatellite loci, sequenced the mitochondrial hypervariable region I, and generated chromosomal R bands for the three formally recognized species and the new hybrids of trans-Andean tamarins. We identified one case of interbreeding between the white-footed tamarin (Saguinus leucopus) and the cotton-top tamarin (S. ?dipus) and two independent reciprocal crosses of S. leucopus and the Geoffroy’s tamarin (S. geoffroyi). All these hybrids exhibit intermediate phenotypes between parental species, and genetic data are consistent with first-generation hybridization. Cytogenetic data suggest that the S. leucopus × S. ?dipus hybrid is sterile, as it is a female with XY karyotype apparently affected by a condition known as gonadal dysgenesis. Trans-Andean tamarin species occur in northwest Colombia with parapatric distributions bounded by major rivers. Potential contact zones, either natural or anthropogenic, might facilitate hybridization in the wild, but this scenario remains to be assessed. Our findings warrant future studies focused on the evolutionary mechanisms of reproductive isolation in tamarins. Given the risk of hybridization, caution should be taken in management and conservation of tamarins.