Chromosome painting shows that the proboscis monkey (Nasalis larvatus) has a derived karyotype and is phylogenetically nested within Asian Colobines

The exceptional diploid number (2n=48) of the proboscis monkey (Nasalis larvatus) has played a pivotal role in phylogenies that view the proboscis monkey as the most primitive colobine, and a long-isolated genus of the group. In this report we used molecular cytogenetic methods to map the chromosomal homology of the proboscis monkey in order to test these hypotheses. Our results reveal that the N. larvatus karyotype is derived and is not primitive in respect to other colobines (2n=44) and most other Old World monkeys. The diploid number of 2n=48 can be best explained by derived fissions of a segment of human chromosomes 14 and 6. The fragmentation and association of human chromosomes 1 and 19 as seen in other Asian colobines, but not in African colobines, is best explained as a derived reciprocal translocation linking all Asian colobines. The alternating hybridization pattern between four segments homologous to human chromosomes 1 and 19 on N. larvatus chromosome 6 is the result of the reciprocal translocation followed by a pericentric inversion. N. larvatus shares this pericentric inversion with Trachypithecus, but not with Pygathrix. This inversion apparently links Nasalis and Trachypithecus after the divergence of Pygathrix. The karyological data support the view that Asian colobines, including N. larvatus, are monophyletic. They share many linking karyological features separating them from the African colobines. The hybridization pattern also suggests that Nasalis is nested within Asian Colobines and shares a period of common descent with other Asian colobines after the divergence of Pygathrix.     

Mapping homology between human and black and white colobine monkey chromosomes by fluorescent in situ hybridization

We used in situ hybridization of chromosome specific DNA probes (“chromosome painting”) of all human chromosomes to establish homologies between the human and the white and black colobus (Colobus guereza 2n = 44). The 24 human paints gave 31 signals on the autosomes (haploid male chromosome set). Robertsonian translocations between chromosomes homologus to human 14 and 15, 21 and 22, form colobine chromosomes 6 and 16, respectively. Reciprocal translocations were found between human chromosomes 1 and 10, 1 and 17, as well as 3 and 19. The alternating hybridization signals between human 3 and 19 on Colobus chromosome 12 show that in this case a reciprocal translocation was followed by a pericentric inversion. The hybridization data show that in spite of the same diploid number and similar Fundamental Numbers, the black and white colobine monkey differs from Presbytis cristata, an Asian colobine, by 6 reciprocal translocations. Comparisons with the hybridization patterns in other primates show that some Asian colobines have a more derived karyotype with respect to African colobines, macaques, great apes, and humans. Chromosome painting also clearly shows that similarities in diploid number and chromosome morphology both between colobines and gibbons are due to convergence. Am. J. Primatol. 42:289–298, 1997. © 1997 Wiley-Liss, Inc.     

Diet of <Emphasis Type="Italic">Pygathrix nigripes</Emphasis> in Southern Vietnam

Black-shanked douc langurs (Pygathrix nigripes) are Southeast Asian colobines about which primatologists know very little, but they are classed as endangered because of population decline due to habitat loss. Two preliminary studies have shown that this monkey is primarily folivorous, but there are few details of plant selection or seasonal changes in diet. We set out to observe douc langurs directly in the wild to quantify the diet during wet and dry seasons. We confirmed that the species relies on foliage throughout the year, but it includes significant proportions of fruit and flowers in its diet when those items are available. The douc langurs selected various parts from 152 species of plants in 2 national parks, but there did not appear to be favorite species that were heavily selected over others. In both the wet and dry seasons, the black-shanked douc langurs ate mostly leaves, but the diversity of plants consumed increased and the proportion of fruit eaten almost doubled in the wet season. There were diurnal shifts in food selection, but we found no evidence that the douc langurs were foraging strategically to maximize their protein or energy intake.     

Mitochondrial data support an odd-nosed colobine clade

To obtain a more complete understanding of the evolutionary history of the leaf-eating monkeys we have examined the mitochondrial genome sequence of two African and six Asian colobines. Although taxonomists have proposed grouping the "odd-nosed" colobines (proboscis monkey, douc langur, and the snub-nosed monkey) together, phylogenetic support for such a clade has not been tested using molecular data. Phylogenetic analyses using parsimony, maximum likelihood, and Bayesian methods support a monophyletic clade of odd-nosed colobines consisting of Nasalis, Pygathrix, and Rhinopithecus, with tentative support for Nasalis occupying a basal position within this clade. The African and Asian colobine lineages are inferred to have diverged by 10.8 million years ago (mya or Ma). Within the Asian colobines the odd-nosed clade began to diversify by 6.7 Ma. These results augment our understanding of colobine evolution, particularly the nature and timing of the colobine expansion into Asia. This phylogenetic information will aid those developing conservation strategies for these highly endangered, diverse, and unique primates.     

It’s Tough Out There: Variation in the Toughness of Ingested Leaves and Feeding Behavior Among Four Colobinae in Vietnam

Colobines are similar in their exploitation of a high percentage of leaf matter. However, this observation obfuscates interesting differences among genera of Southeast Asian colobines in morphology and behavior that may be reflected in the degree to which they rely on mastication or gut volume and gut retention time when ingesting and digesting leaves. We detail the use of a laboratory-based method to measure the mechanical properties of foods selected and processed by 4 captive species of Southeast Asian Colobinae —Pygathrix nemaeus, Pygathrix cinerea, Trachypithecus delacouri, and Trachypithecus laotum hatinhensis— at the Endangered Primate Rescue Center (EPRC), Vietnam. We also detail a field method that quantifies chewing rates and chewing behavior via a consumer-grade video camera and laptop computer. Observations in the captive setting permit a degree of experimental control that is not possible in the wild, and the location of the EPRC in the primates’ habitat country permitted us to provide leaves that they encounter and eat in the wild. We collected toughness data with a portable tester designed by Lucas et al. The average toughness of selected leaves does not differ among the taxa, nor does the length of time spent chewing foods. However, there are differences in feeding rate, with Trachypithecus spp. chewing foods twice as fast as Pygathrix spp. Our findings suggest that Trachypithecus spp. emphasize comminution of food by mastication, while Pygathrix spp. emphasize the comminution of leaf matter in the stomach. The hypothesis is supported by data on molar size, gut mass, and gut morphology. We provide new insights into dietary variation among primate species and detail methods that are typically conducted only in a laboratory setting. We augment the findings with additional data on activity, feeding rates, and tooth morphology.     

The phyletic position and systematics of the douc langurs of Southeast Asia

In recent years, two major questions concerning the phyletic relationships and systematic position of the douc langurs have arisen. These concern, firstly, the taxonomic level at which the doucs as a group should be distinguished and, secondly, the number of taxa of doucs that should be recognized. It has recently been demonstrated on the basis of an exhaustive phylogenetic analysis that the doucs are generically distinct from the snub-nosed langurs and that they should be referred to as species of Pygathrix and Rhinopithecus, respectively [Jablonski and Peng, Folia Primatologica 60:36–55, 1993]. The present investigation was directed toward testing this conclusion using an expanded data set and a different method of character coding, and toward addressing the question as to the number of species or subspecies of doucs that should be recognized. A wide variety of data from large samples of doucs (n = 38), snub-nosed langurs (n = 53), and an out group (macaques; n = 191) were assembled, coded, and analyzed using an interactive computerized program for phylogenetic analysis. The specimens of Pygathrix examined included skeletal specimens, skins, and, when possible, living animals representing the three recognized taxa of doucs, nemaeus nigripes, and moi. The data base for the study comprised 178 characters, including measurements of skeletal specimens (98 characters), qualitative (presence or absence) morphological features (36 characters), characteristics of the pelage (39 characters), and 5 miscellaneous characters. The conclusions of the study were that 1) as a group, the taxa of Pygathrix preserved a larger number of primitive features for the Pygathrix-Rhino-pithecus clade than did the taxa of Rhinopithecus; 2) the taxa of Pygathrix were less different from one another than are the species of Rhinopithecus were from one another; 3) the subspecies Pygathrix nemaeus moi Kloss, 1926 be synonymized with Pygathrix nemaeus nigripes, as suggested by Napier [Catalogue of Primates in the British Museum (Natural History) and Elsewhere in the British Isles. Port III Family Cercopithecidae, Sub-Family Colobinae. London, 1985]; 4) the extant doucs were best recognized as two subspecies, P. nemaeus nemaeus for the red-shanked douc and P. nemaeus nigripes for the black-shanked douc; and 5) the phylogeny of the doucs and snub-nosed langurs proposed by Jablonski and Peng[op cit.,1993] was found to be robust. © 1995 Wiley-Liss, Inc.     

Mitochondrial cytochrome b gene sequences of old world monkeys: With special reference on evolution of Asian colobines

The classification and phylogenetic relationships of the Old World monkeys are still controversial. For Asian colobines, from three to nine genera were recognized by different primatologists. In the present study, we have sequenced a 424 bp mitochondrial tRNA^Thr gene and cytochrome b gene fragment fromMacaca mulatta, Mandrillus sphinx, Mandrillus leucophaeus, Semnopithecus entellus, Trachypithecus vetulus, T. johnii, T. phayrei, T. francoisi, Pygathrix nemaeus, Rhinopithecus roxellanae, R. bieti, R. avunculus, Nasalis larvatus, andColobus polykomos in order to gain independent information on the classification and phylogenetic relationships of those species. Phylogenetic trees were constructed with parsimony analysis by weighting transversions 5 or 10 fold greater than transitions. Our results support the following conclusions: (1) the Old World monkeys are divided into two subfamilies; (2) that among the colobines,Colobus, the African group, diverged first, andNasalis andRhinopithecus form a sister clade toPygathrix; (3) that there are two clades within leaf monkeys, i.e. 1)S. entellus, T. johnii, andT. vetulus, and 2)T. phayrei andT. francoisi; (4) thatRhinopithecus avunculus, R. roxellanae, andR. bieti are closely related to each other, and they should be placed into the same subgenus; (5) thatRhinopithecus is a distinct genus; and (6) that the ancestors of Asian colobines migrated from Africa to Asia during the late Pliocene or early Pleistocene.     

亚洲疣猴面颅和脑颅的比较研究

对亚洲疣猴123个头骨的面颅和脑颅的14项变量作了分析。讨论了东亚古环境的变迁对亚洲疣猴辐射的影响。据分析结果,似乎获得了几个新结论:1)亚洲疣猴可能还有另一条迁移路线——沿特蒂斯海北岸的西藏南部进入我国横断山区,故它们可能有两个分化或辐射中心,即“Sundaland”和我国的横断山地区;2)Nasalis(2n=48)可能是亚洲疣猴中最原始的一个属;3)Pygathrix与Presbytiscus具有最大的相似性,但前者与Phinopithecus相差甚远;4)Phinopithecus无论面颅和脑颅或是起源都是亚洲疣猴中更为特化的一个属。提出了亚洲疣猴系统发育支序图。     

Extinct large colobines from the Plio-Pleistocene of Africa

Three genera and six species of extinct African Plio-Pleistocene Colobinae are discussed. One new genus, Rhinocolobus and three new species, R. turkanaensis, Cercopithecoides kimeui and Paracolobus mutiwa are named. These colobines show a diversity in postcranial and dental morphology not seen among extant species. Rhinocolobus was most similar to extant Colobus in postcranial morphology and had similar high-cusped shearing teeth. Cercopithecoides shows a number of postcranial skeletal features typical of terrestrial cercopithecid species and has lower cusped teeth. Paracolobus, while generally more similar to Rhinocolobus than to Cercopithecoides, is intermediate in some features of its postcranial morphology. The distribution of the various taxa among East and South African sites with different palaeoenvironments is generally consistent with the morphological interpretation. With the exception of Cercopithecoides kimeui, which persisted a little longer, these large colobines disappear from the fossil record about 1.8 million years ago. Their disappearance coincides with an interval of increasing aridity documented at Olduvai Gorge, the Omo Valley, and East Turkana.     

Cranial morphology of the golden monkey (Rhinopithecus) and douc langur (Pygathrix nemaeus)

Because they have been less studied than most other non-human primates (partly due to the difficulties in accessing their habitat) the origins and phylogenetic relationships ofR. roxellana andR. bieti are controversial. These controversies may be clarified to some degree by adding information on the cranium. To this end, ten cranial dimensions analysed morphometrically here provide data about cranial differences among species of the genusRhinopithecus, and between species ofRhinopithecus andPygathrix nemaeus. Though more similar to each other than to any others in the same genus, the results show a significant separation betweenR. roxellana andR. bieti to the degree that they may be regarded as two different species. This confirms the conclusions of prior studies of external features, qualitative morphological characteristics and biochemical evidence (Yeet al, 1987; Zhang and Ryder, 1995; Jablonski, 1998; Penget al., 1988). The differences between these two species are mainly size-related, being highly correlated with cranial length. Other differences, probably non-size related shape differences, however, are highly correlated with cranial width. Sexual dimorphism plays a part in these findings. In relation to the other species, however, the results show that the Vietnam golden monkey (R. avunculus) has closer craniometric relationships with the douc langur (Pygathrix nemaeus) rather than with the three Chinese golden monkey species. Of these, the Gouzhou species (R. brelichi) shares more similarity withR. avunculus and is more separate fromRhinopithecus roxellana and R. bieti. The smaller differentiation between the two latter species could be due to their more recent separation following the dramatic elevation of Qinghai-Tibetan Plateau after the Middle Pleistocene.     

Learning the ropes: The ontogeny of locomotion in red-shanked douc (Pygathrix nemaeus), Delacour's (Trachypithecus delacouri), and Hatinh langurs (Trachypithecus hatinhensis) I. positional behavior

Recent studies at the Endangered Primate Rescue Center (EPRC) in the Socialist Republic of Vietnam's Cuc Phuong National Park by Byron et al. ([2002] Am. J. Phys. Anthropol. [Suppl.] 34:51) and Covert and Byron ([2002] Caring for Primates) revealed unexpected locomotor and postural behaviors in the red-shanked douc langur (Pygathrix nemaeus). This paper further elucidates the question of red-shanked douc suspensory behavior, and provides initial positional behavior data for two other rare Asian colobines, by comparing the ontogenetic positional behavior of red-shanked douc langurs, Delacour's langurs (Trachypithecus delacouri), and Hatinh langurs (Trachypithecus hatinhensis) at the EPRC. Two hundred and seven hours of positional behavior data were collected, with approximately equal amounts of data on each species, and equal amounts on adults and those less than 18 months in age. All young animals were more active than adults, used a wider repertoire of locomotor behaviors, and expressed suspensory behaviors more frequently than did the adults. Young animals also "invented" one new locomotor and two new postural behaviors. These differences are due to both play and explorative behavior, as well as to the youths' changing musculoskeletal systems. The number of positional behaviors utilized by the adults of these species is quite similar to one another (23-32), as is that utilized by the young (51-56). Douc langurs in both age categories used suspensory behaviors more frequently than did Delacour's and Hatinh langurs. Because the uniformity of enclosures offers a control, the results of this study generate hypotheses regarding adaptive radiations and niche partitioning in wild populations.     

The Hand of Cercopithecoides williamsi (Mammalia,Primates): Earliest Evidence for Thumb Reduction among Colobine Monkeys

Thumb reduction is among the most important features distinguishing the African and Asian colobines from each other and from other Old World monkeys. In this study we demonstrate that the partial skeleton KNM-ER 4420 from Koobi Fora, Kenya, dated to 1.9 Ma and assigned to the Plio-Pleistocene colobine species Cercopithecoides williamsi, shows marked reduction of its first metacarpal relative to the medial metacarpals. Thus, KNM-ER 4420 is the first documented occurrence of cercopithecid pollical reduction in the fossil record. In the size of its first metacarpal relative to the medial metacarpals, C. williamsi is similar to extant African colobines, but different from cercopithecines, extant Asian colobines and the Late Miocene colobines Microcolobus and Mesopithecus. This feature clearly links the genus Cercopithecoides with the extant African colobine clade and makes it the first definitive African colobine in the fossil record. The postcranial adaptations to terrestriality in Cercopithecoides are most likely secondary, while ancestral colobinans (and colobines) were arboreal. Finally, the absence of any evidence for pollical reduction in Mesopithecus implies either independent thumb reduction in African and Asian colobines or multiple colobine dispersal events out of Africa. Based on the available evidence, we consider the first scenario more likely.     

Karyotype evolution and sex chromosome differentiation in schistosomes (Trematoda,Schistosomatidae)

The morphology of C-banded metaphase chromosomes has been studied in two hermaphroditic and ten gonochoristic digenetic trematodes (schistosomes). Comparison of numbers and morphology of chromosomes indicates that the karyotype of primitive trematodes probably was composed of 10 (or 11) pairs of telocentric or subtelocentrie chromosomes, and reduction of chromosome numbers in advanced species resulted from centromeric fusion rather than elimination of chromosomes. Observation of heteromorphic chromosomes in a hermaphroditic trematode (Spirorchis) suggested a differentiation of pre-sex chromosomes in species ancestral to dioecious trematodes which possess distinctly differentiated sex chromosomes. Our results indicate that differentiation of Z and W chromosomes in the gonochoristic trematodes resulted from: (a) partial constitutive heterochromatinization of the W chromosome (Schistosoma mansoni and S. haematobium complexes, African schistosomes), (b) deletion of part of the W (S. japonicum and S. mekongi, Asian schistosomes), and (c) translocation of part of one sex chromosome onto another (Schistosomatium douthitti and Heterobilharzia americana, American schistosomes) with subsequent heterochromatinization of the W in H. americana.     

A new low chromosome number forOrnithogalum tenuifolium (Hyacinthaceae)

A new chromosome number (2n=4) forOrnithogalum tenuifolium Delaroche is reported. The new chromosome race is postulated to have originated by a Robertsonian translocation from a Southern African chromosome race with six chromosomes, and represents thus the final step in a series of decreasing basic number of the species.     

Chromosomal location of genes controlling seed proteins in species related to wheat

Summary The seed proteins of Chinese Spring wheat stocks which possess single chromosomes from other plant species related to wheat have been separated by gel electrophoresis in the presence of sodium dodecyl sulphate. Marker protein bands have been detected for both arms of barley chromosome 5, chromosome E (= 1R) and B (= 2R) of rye, chromosomes A,B (= 1C^u) and C (= 5C^u) of Aegilops umbellulata and chromosomes I and III of Agropyron elongatum. These studies, and previous findings, indicate that chromosome 5 of barley, chromosome 1R of rye, chromosome I of Ag. elongatum and possibly chromosome 1C^u of Ae. umbellulata are similar to chromosomes 1A, 1B and 1D in hexaploid wheat in that they carry genes controlling prolamins on their short arms and genes controlling high-molecular-weight (apparent molecular weight greater than 86,000) seed protein species on their long arms. These findings support the idea that all these chromosomes are derived from a common ancestral chromosome and that they have maintained their integrity since their derivation from that ancestral chromosome.     

Mitochondrial DNA sequence and gene order of the Sri Lankan Schistosoma nasale is affiliated to the African/Indian group

A 1.9 kb nucleotide sequence of part of the mitochondrial (mt) genome covering the cox1-trnT-rrnL-trnC-rrnS region, and the order of the remaining mitochondrial protein-coding genes for S. nasale of Sri Lankan origin, has been determined for analysis of the possible placement of this species in the genus Schistosoma. The gene order of this species is similar to that of the African and Indian Schistosoma species, but strikingly different from the East Asian species. Analysis of an alignment of the 1.9 kb sequence with available sequences from other schistosomes indicated affinities with S. spindale (found in Sri Lanka) and African species (in particular S. intercalatum and S. haematobium). Phylogenetic trees inferred from the alignment including 1 kb of RNA (transfer RNA and ribosomal RNA) sequence for 8 other Schistosoma spp. and Fasciola hepatica as an out-group revealed that S. nasale is placed proximally to S. spindale, S. intercalatum, S. haematobium and S. mansoni in the African sub-group while the East Asian species are more distant. S. incognitum lies basal to the combined African/Indian clade. The mtDNA analysis strongly supports the hypothesis that S. nasale is closely affiliated with the African/Indian schistosome group rather than the East Asian Schistosoma species.     

Seasonality of group size,feeding, and breeding in wild red‐shanked douc langurs (Lao PDR)

In Asian colobines, small one‐male groups (OMG) seem to predominate alongside all‐male groups (AMG), while larger multimale groups (MMG) are rare, but are reported for Hanuman langurs and red‐shanked douc langurs. Recently, however, it has been speculated that the genus Pygathrix could have multilevel societies based on (1) a theoretical extension of the multilevel societies found in Rhinopithecus to all odd‐nosed colobines and (2) first data for black‐shanked douc langurs. This assumes bands composed of small OMG with a skewed adult sex ratio. Band size may vary with seasonal food availability resulting in smaller bands when feeding competition is increased. To investigate the social organization of red‐shanked douc langurs and potential seasonal influences, we observed 2 unhabituated groups at Hin Namno National Protected Area, Lao PDR from March 2007 to August 2008 for 803 hr. We recorded births and performed group counts and scan sampling of feeding behavior. Most births (79% of N = 15) occurred from June–September, indicating a 4‐month peak conception season from November to February. Group size averaged 24.5 individuals (range 17–45) with 2.45 adult males (range 1–4). Although the smaller group remained at a stable size (about 18 individuals), the larger group reduced from about 45 to 25 individuals during the 7‐months long lean season, when less than 50% of the feeding time was spent on fruits. This suggests feeding competition as a potential cause of seasonal variation in group size. With 1.9 females per male the skew in adult sex ratio was much lower compared with Rhinopithecus, indicating MMG rather than multilevel societies. However, data on the spacing and interaction patterns between recognized individuals need to be collected and analyzed before the social organization can be determined. Detailed ecological data are furthermore required to investigate the basis for the seasonal changes in group size found. Am. J. Primatol. 73:1134–1144, 2011. © 2011 Wiley Periodicals, Inc.     

A new large Pliocene colobine species (Mammalia: Primates) from Asa Issie, Ethiopia

The Colobinae (Mammalia: Primates) are relatively unknown from the African middle to late Miocene. When they appear in the Pliocene they are unambiguous and already fairly diverse taxonomically, geographically, and ecologically. Discoveries from Pliocene sediments in eastern and southern Africa document a radiation of large-bodied colobines very different from those known today. Paleontological research in Ethiopia has recently led to the discovery and identification of another large-bodied colobine species from the early Pliocene site of Asa Issie, discovered in 2000. This new colobine is larger than but morphologically very similar to its sister taxon Kuseracolobus aramisi, an older taxon also described from the Middle Awash. This new species has significant implications for our understanding of the Pliocene colobine adaptive radiation.     

Phylogenetic relationships among the colobine monkeys revisited: new insights from analyses of complete mt genomes and 44 nuclear non-coding markers

Background

Phylogenetic relationships among Asian and African colobine genera have been disputed and are not yet well established. In the present study, we revisit the contentious relationships within the Asian and African Colobinae by analyzing 44 nuclear non-coding genes (>23 kb) and mitochondrial (mt) genome sequences from 14 colobine and 4 non-colobine primates.

Principal Findings

The combined nuclear gene and the mt genome as well as the combined nuclear and mt gene analyses yielded different phylogenetic relationships among colobine genera with the exception of a monophyletic ‘odd-nosed’ group consisting of Rhinopithecus, Pygathrix and Nasalis, and a monophyletic African group consisting of Colobus and Piliocolobus. The combined nuclear data analyses supported a sister-grouping between Semnopithecus and Trachypithecus, and between Presbytis and the odd-nosed monkey group, as well as a sister-taxon association of Pygathrix and Rhinopithecus within the odd-nosed monkey group. In contrast, mt genome data analyses revealed that Semnopithecus diverged earliest among the Asian colobines and that the odd-nosed monkey group is sister to a Presbytis and Trachypithecus clade, as well as a close association of Pygathrix with Nasalis. The relationships among these genera inferred from the analyses of combined nuclear and mt genes, however, varied with the tree-building methods used. Another remarkable finding of the present study is that all of our analyses rejected the recently proposed African colobine paraphyly and hybridization hypothesis and supported reciprocal monophyly of the African and Asian groups.

Significance

The phylogenetic utility of large-scale new non-coding genes was assessed using the Colobinae as a model, We found that these markers were useful for distinguishing nodes resulting from rapid radiation episodes such as the Asian colobine radiation. None of these markers here have previously been used for colobine phylogenetic reconstruction, increasing the spectrum of molecular markers available to mammalian systematics.     

Fluorescence in situ hybridization establishes homology between human and silvered leaf monkey chromosomes,reveals reciprocal translocations between chromosomes homologous to human Y/5, 1/9, and 6/16, and delineates an X1X2Y1Y2/X1X1X2X2 sex-chromosome system

We employed in situ hybridization of chromosome-specific DNA probes (“chromosome painting”) of all human chromosomes to establish homologies between the human and the silvered lead monkey karyotypes (Presbytis cristata 2n=44). The 24 human paints gave 30 signals on the haploid female chromosome set and 34 signals on the haploid male chromosome set. This difference is due to a reciprocal translocation between the Y and an autosome homologous to human chromosome 5. This Y/autosome reciprocal translocation which is unique among catarrhine primates has produced a X₁X₂Y₁Y₂/X₁X₁X₂X₂ sex-chromosome system. Although most human syntenic groups have been maintained in the silvered leaf monkey chromosomes homologous to human chromosomes 14 and 15, 21 and 22 have experienced Robertsonian fusions. Further, the multiple FISH signals provided by libraries to human chromosomes 1/9, 6/16 indicate that these chromosomes have been split by reciprocal translocations. G-banding analysis shows three different forms of chromosome 1 (X₂) which differ by a complex series of inversions in the 10 individuals karyotyped. Comparisons with the hybridization patterns in hylobatids (gibbons and siamang) demonstrate that resemblances in chromosomal morphology and banding previously taken to indicate a special phylogenetic relationship between gibbons and colobines are due to convergence. A. J. Phys. Anthropol. 102:315–327, 1997. © 1997 Wiley-Liss, Inc.