Leontopithecus Chrysomelas Research Articles

Scanning electron microscopic study of the tongue in golden-headed lion tamarins, Leontopithecus chrysomelas (Callithrichidae: Primates)

Leontopithecus is the largest genus of Callithrichidae, occupying isolated remnants of the Atlantic Forest in Brazil. The objective of this study was to investigate the ultrastructure of the dorsum of the tongue of golden-headed lion tamarins. Tongues of ten adult lion tamarins kept in captivity at the Center of Primatology of Rio de Janeiro (CPRJ-FEEMA) were analyzed under scanning electron microscopy. The three vallate papillae were distributed in a V shape, and each papilla was surrounded by a deep sulcus and an external pad; the medial papilla showed a round shape and the lateral one was elliptical. The filiform papillae were shaped as a crown or as finger-like papillae, and were distributed throughout the tongue, including the margins, except for the posterior region. The fungiform papillae were scattered among the filiform papillae, in a disperse manner, from the apex to the lateral vallate papillae. The foliate papillae had a typical ultrastructure, with folds that ranged in number from 1 to 3. With respect to vallate papillae, we identified the microridge and pore pattern on its surface. Further studies are required to confirm the hypotheses on the ultrastructural aspects described for golden-headed lion tamarins.

Brief communication: Noninvasive measuring of operational tongue length in callitrichids

Callitrichids use their tongue in various social, ecological, and hygienic contexts. Using a noninvasive measuring device, we obtained data on the operational tongue length (OTL) in seven species from the family Callitrichidae. OTL (defined as the maximum tongue extension into the device) varied significantly between species and the width of the device, but did not correlate with mandible length; it is smaller in relation to mandible length in Leontopithecus chrysomelas compared to species from the genera Saguinus and Callithrix. Current information does not allow concluding which of the various functions of the tongue is selecting for tongue length.

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.

Examination of the Taxonomy and Diversification of Leontopithecus using the Mitochondrial Control Region

Leontopithecus comprises 4 taxa: black lion tamarins (L. chrysopygus), golden lion tamarins (L. rosalia), black-faced lion tamarins (L. caissara), and golden-headed lion tamarins (L. chrysomelas). Endemic to the Atlantic Forest of Brazil, they are endangered (Appendix I, CITES; IUCN Critically Endangered: Leontopithecus chrysopygus, L. caissara; IUCN Endangered: L. rosalia, L. chrysomelas). The 4 taxa are differentiated morphologically and geographically and occupy different habitat types. However, it is not clear if all of them are separate species, particularly Leontopithecus caissara, or how they are related to one another evolutionarily. Therefore, we investigated lion tamarin differentiation and radiation. We sequenced the mtDNA control region and performed phylogenetic analyses, population aggregation analyses, and Mantel tests for geographic/genetic correlation. Mitochondrial genetic data suggest 3 distinct lion tamarin clades (Leontopithecus chrysomelas; L. caissara; and L. chrysopygus/L. rosalia). Phylogenetic analysis also supports: 1) the basal lion tamarin is Leontopithecus chrysomelas, and not L. chrysopygus, 2) L. caissara is not subspecific to L. chrysopygus, and 3) Quaternary forest refugia may have shaped lion tamarin diversification via a pattern that does not follow the theory of metachromism. Even though mitochondrial genetic analyses do not unequivocally support the 4 lion tamarins as separate species, one should consider the 4 lion tamarins, with equal conservation priority based on the combination of morphological, genetic, and habitat differentiation. Each of them is an extremely valuable flagship species that focuses attention on the diminishing, highly endemic Atlantic Forest of Brazil.

Polymorphic microsatellite markers for the endangered golden-headed lion tamarin, Leontopithecus chrysomelas (Callitrichidae)

Golden-headed lion tamarins (GHLTs), Leontopithecus chrysomelas, are small fruit-eating primates endemic to the Atlantic Rainforest of South-Bahia, and endangered because of the disappearance of their habitat (2006 IUCN Red List of Threatened Species). The Brazilian Atlantic Rainforest has a unique and extremely rich biodiversity, but continuing deforestation has reduced its surface to less than 7% of its original extension (Tabarelli et al. 2005). Several research and conservation projects are currently running in the field and simultaneously an international captive breeding program has been setup as a backup for the wild population. However, golden-headed lion tamarins were imported from Brazil in small groups. If these consisted of family groups, the current genetic variability in the captive stock might be severely overestimated. Hence we will estimate the genetic relationship between the founders to improve our breeding schemes (e.g. Gautschi et al. 2003). Microsatellite loci make excellent genetic markers for relatedness analyses because they are often highly polymorphic (Blouin et al. 1996). In addition to 14 microsatellite markers, developed for related species and successfully tested for cross-amplification (Galbusera et al. in prep), we report here 9 new microsatellite loci that are variable in golden-headed lion tamarins.

Parasite community interactions: Trypanosoma cruzi and intestinal helminths infecting wild golden lion tamarins Leontopithecus rosalia and golden-headed lion tamarins L. chrysomelas (Callitrichidae, L., 1766)

The parasite prevalence and infection intensity in primate wild populations can be affected by many variables linked to host and/or parasite ecology or either to interparasite competition/mutualism. In this study, we tested how host sex, age, and place of origin, as well parasitic concomitant infections affect the structure of golden lion and golden-headed lion tamarins parasite community, considering Trypanosoma cruzi and intestinal helminths infection in these primates. A total of 206 tamarins from two Atlantic Coastal rain forest areas in Brazil were tested during 4 years for prevalence of T. cruzi infection and helminth prevalence. Three intestinal helminth groups showed high prevalences in both tamarin species: Prosthenorchis sp., Spiruridae, and Trichostrongylidae. An association between presence of T. cruzi infection and higher intestinal helminth prevalence was found in both tamarin species. Two explanations for this association seem to be plausible: (1) lower helminth-linked mortality rates in T. cruzi-infected tamarins and (2) lower elimination rates of helminths in such tamarins. A higher frequency of T. cruzi-positive blood cultures was significantly correlated to female tamarins and to the presence of Trichostrongylidae infection. The possibility of an increase in the transmissibility of T. cruzi and the three analyzed helminths in lion tamarins with concomitant infections is discussed.

EVALUATION OF CONTROL AND TREATMENT OF GONGYLONEMA SPP. INFECTIONS IN CALLITRICHIDS

Numerous cases of Gongylonema spp. infection with associated pathological lesions and clinical signs were identified in a collection of Goeldi's monkeys (Callimico goeldii) (GMs) at a zoological park during a 3-yr period. An increase in the incidence of clinical signs in the GMs and other callitrichid species prompted an investigation to determine the prevalence of infection within the collection and evaluate treatment protocols. Twenty-one callitrichids [nine GMs, four golden lion tamarins (Leontopithecus rosalia), six cotton-top tamarins (Saguinus oedipus), and two golden-headed lion tamarins (Leontopithecus chrysomelas)] were included in this study. Many of the animals had been positively diagnosed on past examinations. Repeated cytological evaluations of scrapings taken from the mucosa of the tongue were performed to diagnose infection. The animals were randomly divided into two groups and treated with either ivermectin (290 microg/kg p.o., q7 days for four doses) or mebendazole (70 mg/kg p.o. q24 hr for three doses). Follow-up scrapings were performed on all animals at days 35, 64, and 156. Numerous animals displayed clinical signs (facial pruritus, inflammation, and ptyalism) before and throughout the investigation; however, Gongylonema spp. infections were only confirmed by tongue scrapings in two animals. Fecal floatation by using a sodium nitrate solution for recovery of spirurid eggs also was performed, but it yielded no positive results. The low number of confirmed cases precluded comparative evaluation of the efficacy of the anthelmintic treatment protocols. However, both regimes seemed subjectively similar in decreasing clinical signs and were safe with no adverse effects. Diagnosis of Gongylonema spp. infection is challenging, even when severe clinical signs are present. This investigation further demonstrates the lack of a reliable ante-mortem test for the parasite and underscores the importance of treatment based on clinical signs. Until a more sensitive test is available, further comparison studies on treatment regimes will be difficult and likely unrewarding.

Associations Between Golden-Headed Lion Tamarins and the Bird Community in the Atlantic Forest of Southern Bahia

We examined the presence of birds accompanying and foraging in proximity to golden-headed lion tamarins at Una Biological Reserve, Bahia, Brazil. We followed 3 groups of golden-headed lion tamarins over 3 yr. We noted all birds ≤5 m of a lion tamarin during 20-min observation periods. We found 11 different bird species in the presence of the lion tamarins. We most often found insectivores, such as woodcreepers and nunbirds, in association with them, eating prey the tamarins flushed. Associations were most frequent in mature and shade-cocoa forests. The group that spent most of its time in mature and shade-cocoa forest was also the group that foraging birds followed most frequently. Differences in resource availability among forest types, such as the abundance of microforaging environments, may affect the frequency and diversity of birds seen in association with golden-headed lion tamarins.

A estrutura do fígado de micos-leões de cativeiro (Callithrichidae, Primates): uma abordagem estereológica

Estudos sobre a morfologia e estereologia hepática são relevantes em pesquisa de anatomia e patologia comparada. Estes também facilitam o uso de primatas não-humanos como modelos experimentais em pesquisa básica, fato que tem auxiliado os estudos em medicina humana. Estudos quantitativos de estruturas hepáticas também têm sido mais prevalentes em Primatas do Velho Mundo e outros vertebrados. Foram estudados vinte e três fígados de micos-leões adultos, sendo : 06 Leontopithecus rosalia, 07 Leontopithecus chrysomelas e 10 Leontopithecus chrysopygus, os quais foram dissecados e fixados com formol tamponado a 10%. Para a quantificação estereológica, o fígado foi considerado como consistindo de parênquima (hepatócitos) e estroma (não-hepatócitos). O parâmetro estereológico densidade de volume (Vv) foi determinado por contagem de pontos, utilizando-se do sistema teste M42. As diferenças estereológicas hepáticas entre as três espécies de micos-leões não foram estatisticamente significativas. Portanto, um valor único de V V [hepatócito] e Vv [estroma] podem ser determinados como 96, 2% e 7,4%, respectivamente. Significantemente diferente, os valores encontrados para o V V [hepatócito] em micos-leões foram 0,09 vez maior do que em babuínos, e 0,17 em humanos. Contudo, o Vv [estroma] foi 1,04 vez menor do que o de babuínos e 1,79 vez menor do que o de humanos. As diferenças encontradas entre as proporções estudadas, mesmo que não comprovadas estatisticamente, mostram a necessidade de estudos futuros para correlacionar os aspectos morfo-fisiológicos destes micos.

Color Vision in Leontopithecus chrysomelas: A Behavioral Study

We assessed the color discriminations by golden-headed lion tamarins (Leontopithecus chrysomelas) via a series of tasks involving a behavioral paradigm that maximizes the naturalness of the stimuli. The stimuli were pairs of Munsell color chips used in earlier experiments with human dichromats. We tested 3 male and 3 female monkeys with stimuli of random brightness values in order to assure that discriminations were based on color rather than brightness cues. Results indicate that each male and one female presented random performances for stimuli resembling hue conditions under which tamarins forage: oranges vs. greens. Two females exhibited discriminations consistent with allelic trichromacy. Findings indicate the presence of an M/L cone opsin polymorphism, a condition of most platyrrhines that is characterized by dichromatic and/or trichromatic females and dichromatic males. Interspecific differences in allelic frequency among lion tamarins raises the possibility that habitat fragmentation is affecting heterozygous frequencies, a trend that could impact tamarin foraging efficiency.

Stereology of the liver in three species of Leontopithecus (Lesson, 1840) Callitrichidae--primates.

Studies on liver morphology and stereology are relevant to the comparative anatomical and pathological research. They also facilitate the use of non-human primates in basic research, which has substantially supported studies in human medicine. Quantitative studies of liver structures have also been more extensive in Old World primates and other vertebrates. Twenty-three livers of adult lion tamarins were studied (six Leontopithecus rosalia, seven Leontopithecus chrysomelas, and 10 Leontopithecus chrysopygus), dissected, and fixed in 10% neutral buffered formalin solution. For stereological quantification, the liver was regarded as consisting of parenchyma (hepatocytes) and stroma (non-hepatocytes). The volume density (V(v)) was determined by point counting, and the disector method was used to obtain the numerical density of hepatocytes (N(v)). Hepatic stereological differences among the three species of lion tamarins were not statistically significant. Therefore, the pooled V(v[hepatocyte]) and V(v[stroma]) could be determined as 96.2 and 7.4%, respectively, and N(v[hepatocyte]) as 500.33 x 10(6) cm(-3). Significantly different, the values found for V(v[hepatocyte]) and N(v[hepatocyte]) in lion tamarins were, respectively, 0.09 and 2.8 times greater than those in baboons, and 0.17 and 3.8 times greater than those in man. However, the V(v[stroma]) was 1.04 times smaller than that in baboons and 1.79 times smaller than that in man.

Re-assessing the reversibility of melengestrol acetate (MGA) implants in golden-headed lion tamarins (Leontopithecus chrysomelas): a comparison with golden lion tamarins (L. rosalia)

AbstractThe reversibility and flexibility of contraceptive methods generally allow for improved genetic and demographic management of captive populations. Earlier studies have produced conflicting results regarding the restoration of reproduction after using melengestrol acetate (MGA) implants in golden-headed (Leontopithecus chrysomelas, GHLT) and golden lion tamarins (L. rosalia, GLT): two closely related species that are physiologically and genetically very similar. The present study investigates the nature of this inter-species difference, presents new data on GHLTs and compares this with published data on GLTs. Analyses showed that around 34% of the GHLTs resumed breeding after their MGA implants were removed or had expired. Non-implanted GHLTs (control group) were significantly more likely to reproduce than females previously treated with an MGA implant, regardless of whether the implant was removed or left to expire. Younger and parous female GHLTs in the control group were more likely to start reproducing. In implanted females, only parity had an impact, with parous females being more likely to resume breeding than non-parous females. In contrast, data published on GLTs indicate that 75% of GLT females resume breeding, and that removing the implant increases the probability of reproduction occurring. Available data suggest that the observed inter-specific differences are related to differences in the weights of the implants used for the two species. For GHLTs, adjusting MGA doses and/or the sizes of the implants currently administered may be required in order to preserve the reproductive potential of individuals. Apart from potentially negative medical and welfare consequences for individual GHLTs, the reduced reversibility of MGA implants also impacts on management practices used to achieve the objectives of conservation breeding programmes. Finally, this study stresses the importance of evaluating the suitability of contraceptive methods at a species-specific level.

Assessment of dexmedetomidine/ketamine anesthesia in golden-headed lion tamarins (Leontopithecus chrysomelas)

ObjectiveTo compare the anesthetic and cardiovascular effects of dexmedetomidine/ketamine combinations in golden-headed lion tamarins. Study designProspective blinded randomized study. AnimalsSix healthy golden-headed lion tamarins, three males and three females were studied (mean body weight ± SD = 0.498 ± 0.054 kg). MethodsThe animals were given one of the dexmedetomidine/ketamine combinations (0.005/10, 0.01/10, and 0.01/5 mg kg−1 IM; treatments 5D/10K, 10D/10K, and 10D/5K, respectively) on three successive occasions. Time to sedation and recumbency, as well as anesthesia, standing, and walking times were recorded. Heart and respiratory rate, arterial blood pressure, hemoglobin saturation, and rectal temperature were recorded during anesthesia. Sedation, muscle relaxation, and auditory response were evaluated after drug administration. ResultsHeart rate decreased after two combinations (10D/5K and 10D/10K). Respiratory rate and rectal temperature progressively decreased in all the treatments. Arterial blood pressures were maintained in 5D/10K and 10D/5K treatments and decreased after 10D/10K administration. There were no differences in sedation and recumbency time between the treatments, but anesthesia time was significantly longer in treatment 10D/10K (67.80 ± 13.30 minutes) compared to treatments 10D/5K (44.54 ± 8.25 minutes) and 5D/10K (30.60 ± 6.80 minutes). Standing time was shorter in treatment 10D/10K (11.13 ± 10.01 minutes) than in treatments 5D/10K (18.20 ± 10.03 minutes) and 10D/5K (19.12 ± 14.55 minutes), and walking time was longer in treatment 5D/10K (20.00 ± 12.46 minutes) compared with treatments 10D/10K (16.00 ± 3.43 minutes) and 10D/5K (12.40 ± 5.02 minutes). Anesthetic quality was significantly better 5 and 15 minutes after treatments 10D/10K and 10D/5K than after treatment 5D/10K. Analgesia scores were higher after administration of 10D/10K than after the 5D/10K treatment. Conclusions and clinical relevanceDexmedetomidine/ketamine is useful for chemical immobilization of golden-headed lion tamarins, but bradycardia and hypotension warrant close monitoring.

The use of degraded and shade cocoa forests by Endangered golden-headed lion tamarins Leontopithecus chrysomelas

Determining habitat requirements for threatened primates is critical to implementing conservation strategies, and plans incorporating metapopulation structure require understanding the potential of available habitats to serve as corridors. We examined how three groups of golden-headed lion tamarins Leontopithecus chrysomelas in Southern Bahia, Brazil, used mature, swamp, secondary and shade cocoa (cabruca) forests. Unlike callitrichids that show affinities for degraded forest, Leontopithecus species are presumed to depend on primary or mature forests for sleeping sites in tree holes and epiphytic bromeliads for animal prey. In this study we quantified resource availability within each habitat, compared the proportion of time spent in each habitat to that based on availability, investigated preferences for sleeping site selection, and determined how golden-headed lion tamarins allocated time to foraging behaviour in different habitats. Each group preferred to range in certain habitats during the day, yet patterns were not consistent across groups. In contrast, all groups preferred to sleep in mature or cabruca forest. Golden-headed lion tamarins spent a greater proportion of time foraging and eating fruits, flowers and nectar in cabruca than in mature or secondary forests. Although the extent to which secondary and cabruca forests can completely sustain breeding groups is unresolved, we conclude that both habitats would make suitable corridors for the movement of tamarins between forest fragments, and that the large trees remaining in cabruca are important sources of food and sleeping sites. We suggest that management plans for golden-headed lion tamarins should focus on protecting areas that include access to tall forest, either as mature or cabruca, for the long-term conservation of the species.

Chromosome painting comparison of Leontopithecus chrysomelas (Callitrichine, Platyrrhini) with man and its phylogenetic position

Using human probes of whole chromosomes, the homoeologies between human and Leontopithecus chrysomelas (Platyrrhini) karyotypes were established. Thirty-three conserved segments were observed between the two species. Intrachromosomal rearrangements between the two species were identified using hybridization of chromosome arm probes of human chromosomes 1 and 3. We also used chromosomal data to investigate phylogenetic relationships of Callitrichines. These data were encoded using Cebus capucinus , a species which kept fairly ancestral chromosomes, as reference. Two equi-parsimonious trees, including reversion or convergence events, were obtained. The monophyly of Callitrichines is confirmed. They share nine chromosomal rearrangements at least. The Cebuella-Callithrix group forms a clade sharing five rearrangements at least. According to the tree considered, the Tamarins, Leontopithecus and Saguinus share two chromosomal rearrangements restricted to these two taxa or none. Callimico accumulated seven chromosomal rearrangements unshared with other taxa, at least. To avoid convergence and reversion events, we propose the hypothesis of a network (or populational) evolution. Six chromosomal rearrangements would have occurred during the period of this network evolution. Finally, the karyotype of the last common ancestor to all Callitrichines has been reconstructed. It possessed 48 chromosomes.

Characteristics of reproductive biology and proximate factors regulating seasonal breeding in captive golden-headed lion tamarins (Leontopithecus chrysomelas).

Reproduction is highly demanding in terms of energy expenditure, and the costs and benefits associated with postponing or investing in a reproductive effort are crucial determinants of an individual's fitness. Understanding the reproductive potential of a species under varying ecological conditions offers important insights into the dynamics of its social system. This study provides the first detailed analysis of the reproductive potential of wild- and captive-born golden-headed lion tamarins (Leontopithecus chrysomelas) under captive conditions, based on studbook data compiled during 1984-2000. Litters produced by wild-born females breeding in captivity are similar in size to litters observed in the wild, but smaller than litters of captive-born females. The more stringent ecological conditions experienced by wild-born females during maturation may result in a lifelong effect on litter size. However, interbirth intervals are shorter for wild-born than captive-born females. The relatively smaller burden of infant care that results from having smaller litters may allow wild-born females to sustain the next pregnancy sooner. Reproduction in the Brazilian captive population is highly seasonal for both wild-born females and females born in captivity in Brazil. Changes in photoperiod over a year provide a proximate explanation for changes in the proportion of conceptions and births per month. Outside Brazil, breeding occurs year-round, and no clear birth peak is apparent. Information from field reports that could be used to relate this finding to ecological factors, such as resource availability, is unavailable.

Stability of Breeding and Non-Breeding Groups of Golden-Headed Lion Tamarins(Leontopithecus Chrysomelas)

AbstractIn Callitrichid primates, offspring remain in their natal group beyond the age of sexual maturity, increasing the group's inclusive fitness by cooperatively rearing their siblings. Contraception of the dominant female in these groups may alter the associated costs and benefits of this cooperative rearing in such a way that offspring themselves attempt to breed when a period longer than the normal inter-birth interval of one year has elapsed. Contraception of the dominant female may also induce changes in socio-sexual interactions between group members, which can lead to increased aggression after a short period. In this study, we investigated the occurrence of aggression in 16 captive groups of golden-headed lion tamarins(Leontopithecus chrysomelas)under three conditions: 1) no contraception used; 2) contraception used and offspring younger than one year present within the group; and 3) contraception used and all offspring in the group older than one year. We found that the probability of aggression occurring in the groups was best predicted by logistic regression models containing the factors ‘group size ‘ and ‘overall proportion of males ‘ or ‘number of sons ‘. Aggression was more likely in larger groups with a high proportion of males or a large number of sons. This effect was significantly stronger for groups in which all offspring were older than one year. Absence of dispersal opportunities and differences in male and female reproductive strategies may explain the observed patterns. The increased instability of large non-breeding groups presents a problem when using long-term contraceptive methods and should be taken into account when making decisions on the most suitable population-control procedures.

Comments from The Aza Contraception Advisory Group on Evaluating the Suitability of Contraceptive Methods in Golden-Headed Lion Tamarins (Leontopithecus Chrysomelas)

AbstractReversible contraceptives, such as melengestrol acetate (MGA) implants, have become an invaluable tool that captive-animal managers use to maintain various species in social groupings while avoiding unwanted pregnancies. The American Zoo and Aquarium Contraception Advisory Group (AZA CAG) monitors the efficacy, reversibility, and safety of contraceptives used in captive exotic mammals worldwide. Because so few data exist on contraceptive efficacy and safety in exotic species, it is critical that evaluations reflect an understanding of the mechanism of action of the active ingredient as well as of the delivery system. The following discussion addresses the concerns of the CAG over the manner in which De Vleeschouwer et al (Animal Welfare 2000,9: 251-271) analysed MGA implant reversibility data in golden-headed lion tamarins.

Restoration of reproductive potential following expiration or removal of melengestrol acetate contraceptive implants in golden lion tamarins (Leontopithecus rosalia).

Although reversible contraception is important to successful management of small populations, there are concerns about the reversibility of melengestrol acetate (MGA), the most commonly used implant in captive animals. Female golden lion tamarins (Leontopithecus rosalia) placed in potential breeding situations after surgical MGA implant removal showed a 75% return to reproduction within 2 yr, unlike golden-headed tamarins (Leontopithecus chrysomelas), which have had a 29% return to reproduction following implant removal. This rate was indistinguishable from the breeding probability for newly formed pairs involving nonimplanted females. Litter size, stillbirth rate, and infant survival rate were not significantly different between nonimplanted and implant-removed female golden lion tamarins. However, females with implants left in (and assumed to have expired) showed higher stillbirth and infant mortality rates than did females with implants removed. For seven female golden lion tamarins for which reproductive histories before and after MGA implantation were available, litter size was unaffected by MGA implantation and subsequent removal. Infant survival rate for these females appeared to be lower after removal but was indistinguishable from rates in the nonimplanted females. Prior reproductive experience, length of time with an implant, and age of the females did not affect the probability of breeding for females after removal of the implants. Overall, breeding probability of nonimplanted females declined with age. Although the results of this study confirm the reversibility of MGA implants in golden lion tamarins, there appear to be some effects on viability of offspring, particularly offspring born to females with implants left in and presumed expired.

Phylogeny of lion tamarins (Leontopithecus spp) based on interphotoreceptor retinol binding protein intron sequences.

The evolutionary relationships of the lion tamarins (Leontopithecus) were investigated using nuclear interphotoreceptor retinol binding protein (IRBP) intron sequences. Phylogenetic reconstructions strongly support the monophyly of the genus, and a sister relationship between the golden lion tamarin, Leontopithecus rosalia, and the black lion tamarin, L. chrysopygus, to the exclusion of the golden-headed lion tamarin, L. chrysomelas. The most parsimonious evolutionary reconstruction suggests that the ancestral lion tamarin and the common ancestor of L. rosalia and L. chrysopygus had predominantly black coats. This reconstruction is not consistent with a theory of orthogenetic evolution of coat color that was based on coat color evolution in marmosets and tamarins. An alternative reconstruction that is consistent with metachromism requires that ancestral lion tamarins had agouti hairs.