Phylogenetics and an updated taxonomic status of the Tamarins (Callitrichinae, Cebidae).

Traditionally, Saguinus has been organized into six taxonomic groups: bicolor, inustus, midas, mystax, nigricollis, and oedipus. After recent revisions, taxonomic reclassifications were proposed, including (1) the recognition of Leontocebus as a new genus, and (2) the subdivision of Saguinus into three subgenera. Nonetheless, the contradictory nature of these results reinforces the inconsistency concerning the monophyletic status of tamarins and its interspecific phylogeny. Therefore, in this study, we carried out phylogenetic inferences of Saguinus based on 44 molecular markers, of which 37 were from nuclear DNA and seven from mitochondrial DNA. A final dataset of 24,202 base pairs (bp) was obtained from 60 specimens of all recognized species of Saguinus and, also representatives of two main lineages of Leontocebus. Phylogenetic hypothesis was obtained from Maximum Likelihood (ML) and Bayesian inference (BI) methods. We also construct a Species Tree and a fossil-calibrated multi-locus phylogeny to estimate the time of divergence of Tamarins. Our phylogenetic results validated Leontocebus, or nigricollis group, as monophyletic, and recovered additionally three main clades within Saguinus. Same topology was obtained by the Species Tree. These clades correspond to (1) inustus + mystax groups, (2) oedipus group and (3) bicolor + midas group. Our results show support for a 10.5-million-year-old split between Leontocebus and the remaining Saguinus, followed by two other cladogenetic events, around 9.3 and 7.2 mya, which lead to the rise of the main clades of Saguinus. These phylogenetic data, in concert with the consistent morphological, ecological behavior and biogeographic evidence suggest a new classification for the Amazonian and trans-Andean tamarins. Therefore, we support the validation of Leontocebus as genus and recommend the split of Saguinus into three genera: (1) Tamarinus (inustus and mystax groups), (2) Oedipomidas (oedipus group), and (3) Saguinus (bicolor and midas groups).

Evolution and biogeographic history of the Saguinus mystax group (Primates, Callithrichidae).

The Saguinus mystax group traditionally includes three species, S. mystax, S. labiatus, and S. imperator. The additional inclusion of S. inustus is argued on molecular grounds, which have an important impact on our comprehension of the phenotypical evolution and biogeography of the group. Here, we investigate the evolutionary events leading to the diversification of the S. mystax group, integrating phylogenetic, temporal, and geographic information with the current knowledge of the Amazonian paleogeographical history. The examination of 208 specimens of Saguinus resulted in 25 morphological characters, of which 13 were used for the first time in a phylogenetic analysis of the genus. Morphological characters were also combined with molecular data and analyzed using Bayesian and Maximum Likelihood methods. Trees resulting from morphological and combined data recovered a monophyletic S. mystax group, including S. inustus, whose inclusion was supported by two morphological synapomorphies. Molecular based age estimates place the origin of Saguinus in the middle Miocene (17.4-13 million years ago [mya]), whereas the S. mystax group originated in an interval between 12 and 6 mya. Our results also suggest that the ancestral area of Saguinus was western Amazon, from where they dispersed to their current distribution after the end of the Pebas lakes system. The diversification events in the S. mystax group are related to the Pliocene development of the modern Amazon river network associated to the uplift of Fitzcarrald Arch.

Abdominal ultrasound in Saguinus ursulus.

BACKGROUND: The classification of Saguinus ursulus as a new taxon and the vulnerability of this species highlighted the need for data on its specific morphophysiological attributes. This study used ultrasound to determine the typical characteristics of pelvic-abdominal structures and organs. METHODS: Nine healthy primates of the species S. ursulus were evaluated, through ultrasound tests, to determine the morphometry of the organs of the pelvic-abdominal cavity and the levels of ovarian activity. RESULTS: Topography, morphology, and biometrics of the organs were described. It was observed that organs of S. ursulus are similar to those of other Neotropical primate species. However, the kidney morphology is different,the left is triangular and the right is elliptical, while the gallbladder is bilobed. CONCLUSION: Ultrasonography has proven to be efficient and effective for organ evaluation. The ultrasound findings are a first step toward understanding the physiology of a less-known species.

Gross anatomy of the shoulder and arm intrinsic muscles in the white-footed tamarin (Saguinus leucopus - Günther, 1876): Inter- and intraspecific anatomical variations.

BACKGROUND: Saguinus leucopus is a Neotropical primate with an arboreal quadrupedal locomotion pattern, which requires wide movements of the shoulder and arm. This investigation studies the muscles of these regions in order to serve as a basis for clinical and surgical procedures and to compare with other primates. METHODS: Gross dissections of twenty thoracic limbs were performed. RESULTS: The muscles examined were the deltoid, supraspinatus, infraspinatus, subscapularis, teres major, teres minor, coracobrachialis longus, coracobrachialis brevis, biceps brachii, brachialis, triceps brachii, tensor fasciae antebrachii, and anconeus epitrochlearis. The anconeus was absent. The following variants were found: an accessory head of the biceps brachii, the unilateral absence of the short head of the biceps brachii, an accessory head of the coracobrachialis longus, and one infraspinatus muscle innervated by the axillary nerve. CONCLUSIONS: These muscles are adapted to quadrupedal locomotion and can have inter- and intraspecific variations in their attachments and innervation.

A Novel Method for Assessing Enamel Thickness Distribution in the Anterior Dentition as a Signal for Gouging and Other Extractive Foraging Behaviors in Gummivorous Mammals.

Gummivory poses unique challenges to the dentition as gum acquisition may often require that the anterior teeth be adapted to retain a sharp edge and to resist loading because they sometimes must penetrate a highly obdurate substrate during gum extraction by means of gouging or scraping. It has been observed previously that the enamel on the labial surface of the teeth used for extraction is thicker relative to that on the lingual surface in taxa that extract gums, while enamel is more evenly distributed in the anterior teeth of taxa that do not regularly engage in extractive behaviors. This study presents a quantitative methodology for measuring the distribution of labial versus lingual enamel thickness among primate and marsupial taxa in the context of gummivory. Computed microtomography scans of 15 specimens representing 14 taxa were analyzed. Ten measurements were taken at 20% intervals starting from the base of the crown of the extractive tooth to the tip of the cutting edge across the lingual and labial enamel. A method for including worn or broken teeth is also presented. Mann-Whitney U tests, canonical variates analysis, and between-group principal components analysis were used to examine variation in enamel thickness across taxa. Our results suggest that the differential distribution of enamel thickness in the anterior dentition can serve as a signal for gouging behavior; this methodology distinguishes between gougers, scrapers, and nonextractive gummivores. Gouging taxa are characterized by significantly thicker labial enamel relative to the lingual enamel, particularly towards the crown tip. Examination of enamel thickness patterning in these taxa permits a better understanding of the adaptations for the extraction of gums in extant taxa and offers the potential to test hypotheses concerning the dietary adaptations of fossil taxa.

Genetic correlations in the dental dimensions of Saguinus fuscicollis.

OBJECTIVES: The objectives of this study are to describe genetic correlations between dental dimensions in a platyrrhine primate, to assess whether the brown-mantled tamarin dentition exhibits genetic modularity by tooth type, and to discuss the relationship between body size reduction and the genetic architecture of dental traits. MATERIALS AND METHODS: Genetic correlations were estimated for linear dental measurements, estimated crown areas, and measures of relative premolar and molar size from 302 individuals, using a pedigree of 386 individuals, with maximum likelihood variance decomposition in SOLAR. RESULTS: Genetic correlation estimates indicate strong genetic integration in the dentition of brown-mantled tamarins, with little evidence of modularity by tooth type, within and between the maxilla and mandible. The relative molar size variable hypothesized to be genetically patterned in baboons is not significantly heritable, and relative premolar size does not meet the criteria to be considered genetically patterned in this population. DISCUSSION: These results demonstrate variation in the pattern of genetic correlations between dental dimensions in primates, providing evidence of evolution of the genetic architecture in the callitrichine lineage. Genetic integration of dental dimensions without modularity by tooth type, as demonstrated here, is expected to constrain dental evolution in ways that modularity would not. The role of body size reduction in the callitrichine lineage in the evolution of the genetic architecture of the dentition is discussed. Quantitative genetic analyses of dental dimensions in more primate populations will provide greater evidence of variation and evolution in the genetic architecture underlying primate dental morphology.

Genetic contributions to dental dimensions in brown-mantled tamarins (Saguinus fuscicollis) and rhesus macaques (Macaca mulatta).

OBJECTIVES: The use of dental metrics in phylogenetic reconstructions of fossil primates assumes variation in tooth size is highly heritable. Quantitative genetic studies in humans and baboons have estimated high heritabilities for dental traits, providing a preliminary view of the variability of dental trait heritability in nonhuman primate species. To expand upon this view, the heritabilities and evolvabilities of linear dental dimensions are estimated in brown-mantled tamarins (Saguinus fuscicollis) and rhesus macaques (Macaca mulatta). MATERIALS AND METHODS: Quantitative genetic analyses were performed on linear dental dimensions collected from 302 brown-mantled tamarins and 364 rhesus macaques. Heritabilities were estimated in SOLAR using pedigrees from each population, and evolvabilities were calculated manually. RESULTS: Tamarin heritability estimates range from 0.19 to 0.99, and 25 of 26 tamarin estimates are significantly different from zero. Macaque heritability estimates range from 0.08 to 1.00, and 25 out of 28 estimates are significantly different from zero. DISCUSSION: Dental dimensions are highly heritable in captive brown-mantled tamarins and free-ranging rhesus macaques. The range of heritability estimates in these populations is broadly similar to those of baboons and humans. Evolvability tends to increase with heritability, although evolvability is high relative to heritability in some dimensions. Estimating evolvability helps to contextualize differences in heritability, and the observed relationship between evolvability and heritability in dental dimensions requires further investigation.

Postcranial Skeletal Differences in Free-Range and Captive-Born Primates.

Skeletal morphology is important in evolutionary, genetic, developmental, physiological, and functional studies. Although samples from free-ranging individuals may be preferable, constraints of sample size, demography, or conservation status may necessitate the inclusion of captive-born individuals. Captivity may be associated with physical, physiological, or behavioral differences that may affect skeletal form. This study assesses differences in postcranial skeletal form between free-range and captive-born Macaca mulatta and Saguinus oedipus. Samples included free-range M. mulatta from Cayo Santiago (Caribbean Primate Research Center) and captive-born macaques from the Wisconsin National Primate Research Center. S. oedipus samples included free-range born and captive-born individuals from the Oak Ridge Associated Universities Marmoset Research Center. Twenty-four dimensions of various bones, including the scapula, upper limb, innominate and lower limb, were recorded for adults. Age of epiphyseal closure was recorded for immature captive-born M. mulatta. Analysis of variance and principal component analyses tested significant differences between free-range born and captive-born individuals in each species. Significant differences were present in size and shape of postcrania between free-range and captive-born within taxa. Free-range macaques were larger than captive-born macaques, but this pattern did not consistently carry over to the Saguinus samples. Shape differences, while present throughout the skeleton, were especially prominent in the scapula. Differences in developmental timing, nutrition, and physical activity can be expected to contribute to the observed differences in postcranial skeletal form. These differences should be considered when captive-born primates are included in morphological or evolutionary studies. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:761-774, 2019. © 2018 Wiley Periodicals, Inc.

Morphometric, anatomic and radiographic study of the scapula in the white-footed tamarin (Saguinus leucopus): report of scapular cartilage and one variation in cranial (superior) transverse scapular ligament.

The white-footed tamarin (Saguinus leucopus) is an endangered endemic primate of Colombia, mainly due to the deforestation of its habitat and illegal trade, which generates a high incidence of these animals in wildlife care centres. Musculoskeletal system disorders in S. leucopus are one of the most common diseases and therefore the aim of this study was to contribute to the morphologic studies with a morphometric, anatomic and radiographic description of the scapula in this species to provide a basis for medical interventions, surgical approaches, radiologic diagnoses and comparative functions of this bone. Gross dissections of each scapular region were made in eight specimens without a diagnosis of osteomuscular disease. These specimens died from natural cases in the wildlife care centres of the Corporación Autónoma Regional de Caldas (CORPORCALDAS); after necropsy their carcasses were fixed with 10% formaldehyde, 5% mineral oil and 1% phenic acid in these centres over the course of at least 1 week. X-rays of the scapula were taken in the small animal clinic of the Universidad del Tolima, and morphometric data of the scapulae were obtained with a digital calliper. The scapula of the white-footed tamarin was a flat triangular bone with a deep scapular notch in its cranial margin, where there was a cranial transverse scapular ligament that was absent in two specimens. The coracoid process was highly developed, medially covering the humeral joint. The dorsal margin was covered by the scapular cartilage, which was highly developed in the caudal angle. In the dorsal fourth of the caudal margin, there was a surface from which the m. teres major originated. The lateral surface had a scapular spine with a long hamatus process of the acromion until the lateral part of the humeral joint. The infraspinatus fossa was wider than the supraspinous fossa. On the costal surface, the subscapular fossa was formed by three subscapular lines and one subscapular ridge, the latter helping to form the surface for the m. teres major. In the two radiographic views, caudocranial to the scapula and dorsoventral to the thorax, the scapular spine, acromion, coracoid process, scapular incisura, supraglenoid tubercle, caudal margin, subscapular ridge, and the joints with the clavicle and the humerus could be observed. The scapula of the white-footed tamarin presented bony reliefs that share characteristics with other primates but also with domestic mammals due to its quadrupedal locomotion, which allowed us to correlate its morphologic adaptation with its quadrupedal arboreal displacement.

Anatomic description of the palmaris longus muscle and report of variant nerve supply in the white-footed tamarin (Saguinus leucopus Günther, 1876).

The gross anatomy of the palmaris longus muscle in 12 specimens of Saguinus leucopus was studied by dissection. This muscle was constant and unipennate, originated in the medial epicondyle of the humerus; inserted onto flexor retinaculum and palmar aponeurosis; and innerved by the median nerve, and in one case, together with the ulnar nerve. This is the first report of double innervation for this muscle in primates.

Anatomic description of the ulna of the white-footed tamarin (Saguinus leucopus Günther, 1876) / Descripción anatómica de la ulna del tití gris (Saguinus leucopus Günther, 1876)

This document is a description of the macroscopic functional anatomy of the ulna bony prominences in the White-footed Tamarin (Saguinus leucopus), a neotropical endemic, and monotypic primate of Colombia. Few studies have been conducted on its anatomy, and thus its ulnar morphology, an essential element for this animal's quadrupedal arboreal locomotion, remains unknown. This study is based on eight specimens, fixed in formalin at 10 % whose ulnas were extracted in order to describe the main bony prominences along with muscular and ligamentous fixation functions. These elements of the locomotor apparatus and the multiple anatomical contours of the ulna of the White-footed Tamarin, exhibit characteristics for positional and articular adjustment with other bones of the forelimb in harmony with the attachments of the muscles, essential for quadrupedal arboreal locomotion.

El presente trabajo es una descripción de la anatomía macroscópica y funcional de los relieves óseos de la ulna del tití gris (Saguinus leucopus), un primate neotropical, endémico y monotípico de Colombia, con escasos estudios sobre su anatomía, y por ende de la morfología ulnar, elemento fundamental para la locomoción cuadrúpeda de este animal arbóreo que permanece desconocida. Para ello, se tomaron como base del estudio ocho especímenes fijados con formalina al 10 % y de ellos se extrajeron sus ulnas, describiendo los principales relieves óseos con sus funciones de fijación muscular y ligamentosa. Estos elementos del aparato locomotor con sus múltiples relieves anatómicos de la ulna del tití gris, presentan características para la adaptación posicional y articular con otros huesos del miembro torácico de manera armónica para la fijación de músculos indispensables en su locomoción cuadrúpeda arbórea.

Descriptive anatomy of lateral digital extensor muscles of the hand of the white-footed tamarin (Saguinus leucopus Günther, 1876) / Anatomía descriptiva de los músculos extensores digitales laterales de la mano del tití gris (Saguinus leucopus Günther, 1876)

The Saguinus leucopus is an endemic and monotypic primate of Colombia with quadrupedal arboreal locomotion, but the study of its morphological adaptations are still scarce, therefore the specific knowledge of its muscles will allow to understand these adaptations and to establish better medical and surgical procedures in order to preserve this species. For this purposes, the two forearms of 10 S. leucopus specimens were dissected, they were fixed within a formaldehyde solution, phenic acid and mineral oil mixture. Among the craniolateral muscles of the forearm two muscles were independent for digits IV and V. They presented form, origin and insertion suitable for individual extension of each digit, with innervation and irrigation by the cranial interosseous nerve and the homonymous artery respectively; they show similarities and differences with other primates, it allows to conclude that the development of these muscles could enable a particular anatomical and functional individualization in these digits extension, this feature makes possible its quadrupedal arboreal locomotion.

El Saguinus leucopus es un primate endémico y monotípico de Colombia con la locomoción cuadrúpeda arbórea, sin embargo los estudios de sus adaptaciones morfológicas aún son escasos, por lo tanto, el conocimiento específico de sus músculos permitirá conocer estas adaptaciones y establecer mejores procedimientos médicos y quirúrgicos con el fin de preservar esta especie. Para estos fines, se disecaron los dos antebrazos de 10 especímenes de S. leucopus, los cuales fueron fijados con una solución en mezcla de formaldehído, aceite mineral y ácido fénico. Entre los músculos cráneo laterales del antebrazo se encontraron dos músculos independientes para los dígitos IV y V. La forma, el origen y la inserción eran adecuadas para la extensión individual de cada dígito, con la inervación e irrigación por el nervio interóseo craneal y la arteria del mismo nombre respectivamente, presentando similitudes y diferencias con otros primates, lo que permite llegar a la conclusión que el desarrollo de estos músculos podría permitir una individualización anatómica y funcional particular en la extensión de estos dígitos, haciendo posible su locomoción cuadrúpeda arbórea.

Fluctuating and directional asymmetry in the long bones of captive cotton-top tamarins (Saguinus oedipus).

OBJECTIVES: Skeletal asymmetries reflect developmental stability and mechanical, functional, and physiological influences on bone growth. In humans, researchers have documented the greatest limb bone bilateral asymmetry in diaphyseal breadths, with less asymmetry in articular and maximum length dimensions. However, it remains unclear as to whether the pattern observed for humans is representative of nonhuman primates, wherein bilateral loading may minimize directional asymmetry. This study adds to the small body of asymmetry data on nonhuman primates by investigating patterns of long bone asymmetry in a skeletal sample of Saguinus oedipus (cotton-top tamarin). MATERIALS AND METHODS: Humeri, radii, ulnae, femora, and tibiae of 76 adult captive cotton-top tamarin skeletons (48 males, 28 females) were measured bilaterally. We included maximum length, midshaft diaphyseal breadths, and at least one articular measurement for each bone to assess directional (DA) and fluctuating asymmetry (FA) in each dimension. RESULTS: Most dimensions exhibit significant FA, and very few have significant DA; DA is limited to the lower limb, especially in knee dimensions. Overall, the magnitudes of asymmetry in tamarins have a consistent ranking that follows the same pattern as found in humans. DISCUSSION: This first study of DA and FA among multiple dimensions throughout the limbs of a non-hominoid primate suggests that previously-reported patterns of human bilateral asymmetry are not exclusive to humans. The results further indicate potential underlying differences in constraints on variation within limb bones. While processes shaping variation await further study, our results argue that different long bone dimensions may reflect dissimilar evolutionary processes.

Descripción anatómica del músculo braquiorradial del tití gris (Saguinus leucopus Günther, 1877) y el hallazgo de una cabeza accesoria como variante anatómica / Anatomical description of white-footed tamarin (Saguinus leucopus Günther, 1877) brachioradialis muscle, and the finding of an accessory head as an anatomical variant

El Saguinus leucopus es un primate neotropical, endémico y monotípico de Colombia, con escasos estudios sobre su anatomía, en especial de sus músculos, siendo estos un elemento fundamental para la locomoción activa de este primate en los árboles. El objetivo del presente estudio fue describir la anatomía macroscópica del músculo braquiorradial del tití gris (Saguinus leucopus), tomando como base del estudio diez especímenes fijados con formalina al 10%, y a cada uno de ellos se les disecó los dos miembros torácicos de superficial a profundo, describiendo la forma, el origen, la inserción, la inervación y la irrigación del músculo braquiorradial. Se concluye que es un músculo que presenta una morfología, que debe contribuir a los movimientos flexores y supinadores del codo, y puede llegar a tener una cabeza accesoria en esta especie.

The Saguinus leucopus is a neotropical, endemic, and monotypic Colombian primate; few studies have been reported about its anatomy, specially about its muscles, this being a fundamental element for the active motion of this primate in the trees. The aim of this study was to describe the gross anatomy of the brachioradialis muscle on the white-footed tamarin (Saguinus leucopus). Ten specimens were included in the study, fixed with formalin at 10% and their thoracic limbs dissected, from the superficial to the deep plane, describing the form, origin, insertion, innervation and irrigation of the Brachioradialis muscle. The conclusion we made is that this muscle represents a morphology and in this way it must contribute to the flexor and supinator elbow movements, and would have an accessory head in this species.

Re-description and assessment of the taxonomic status of Saguinus fuscicollis cruzlimai Hershkovitz, 1966 (Primates, Callitrichinae).

Cruz Lima's saddle-back tamarin Saguinus fuscicollis cruzlimai Hershkovitz, 1966, was described from a painting by Eládio da Cruz Lima in his book Mammals of Amazonia, Vol. 1, Primates (1945). The painting was of four saddle-back tamarins from the upper Rio Purus, one of them distinct and the inspiration for Hershkovitz to describe it as a new subspecies. Its exact provenance was unknown, however, and the specimen was lost. Surveys in the Purus National Forest in 2011 resulted in sightings of this tamarin along the north bank of the Rio Inauini, a left-bank tributary of the middle Purus, and also on the left bank of the Purus, north and south of the Rio Inauini. It is possible that it extends north as far as the Rio Pauini, and that S. f. primitivus Hershkovitz, 1977, occurs north of the Pauini as far the Rio Tapauá, both also left-bank tributaries of the Purus. Morphometric and molecular genetic analyses and the coloration of the pelage indicate that this tamarin differs from its neighbors sufficiently to be considered a full species. In his doctoral dissertation [2010, Taxonomy, Phylogeny and Distribution of Tamarins (Genus Saguinus Hoffmannsegg, 1807) Georg-August Universität, Göttingen], C. Matauschek found that saddle-back and black-mantle tamarins diverged from the tamarin lineage around 9.2 million years ago; time enough to warrant their classification in a distinct genus. Leontocebus Wagner, 1840, is the first name available. In this article we re-describe Cruz Lima's saddle-back tamarin. We propose a neotype with a precise locality, and make it a full species in the genus Leontocebus.

Anatomical and functional description of the radius of white footed tamarin (Saguinus leucopus) / Descripción anatómica y funcional del radio del tamarino manos blancas (Saguinus leucopus)

Saguinus leucopus is a neotropical primate, endemic and monotypic of Colombia (South America), with few studies of its anatomy, whose morphology radius this key element of this quadruped locomotion arboreal animal remains unknown. This study describes the gross functional anatomy of the radius bone of white-footed tamarin (Saguinus leucopus). The study was based on eight specimens fixed with 10% formalin and extracted their radius them, describing the main features of the bony prominences, such as muscle and ligaments attachments and neurovascular pipes. The radius of Saguinus leucopus bony presents some prominences for muscles and ligaments attachments, in addition to the synovial cartilage regions to other parts of the forelimb. The various anatomical contours of the radius of Saguinus leucopus exhibit characteristics typical particular motor functions adapted to the environment of an arboreal quadruped position.

Saguinus leucopus es un primate neotropical, endémico y monotípico de Colombia, con escasos estudios sobre su anatomía, y por ende de la morfología radial, elemento fundamental para la locomoción cuadrúpeda de este animal arbóreo que permanece desconocida. El objetivo fue describir la anatomía macroscópica y funcional de los relieves óseos del radio del titi gris (Saguinus leucopus). Se tomaron como base del estudio ocho especímenes fijados con formalina al 10% y de ellos se extrajeron sus radios, describiendo completamente su anatomía macroscópica. Los principales relieves óseos con sus funciones de fijación muscular y ligamentosa, y canalizaciones neurovasculares. El radio del Saguinus leucopus presenta algunas prominencias óseas fijaciones musculares y ligamentosas, además presenta regiones de cartílago sinovial para articular con otras partes del miembro anterior. Los variados relieves anatómicos del radio del Saguinus leucopus presentan características típicas particulares, adaptadas a funciones motoras para su ambiente propio de una posición arbórea cuadrúpeda.

Histology of the suprapubic and anogenital cutaneous glands in male cotton top tamarins (Saguinus oedipus).

In cotton top tamarins (Saguinus oedipus), scent glands have been mostly studied in females from museum collections. This work aims to extend the investigation to male specimens, introducing a novel source of skin samples. Two adult males from zoo populations, one intact and one castrated, were immediately frozen after natural death. Skin samples were later collected at the thawing onset, soaked with cold fixative and processed for light microscopy. Sebaceous units of scent glands showed phasic secretory activity in the intact male and marked fibrosis in the castrated male. It appears, therefore, that light microscopy samples from frozen tissues provide detailed features that can disclose distinctive traits in specimens characterized by different hormonal balances.

Descripción anatómica y funcional del húmero del tití gris (saguinus leucopus) / Anatomical and funcional description of humerus in the white-footed tamarin (saguinus leucopus)

El Saguinus leucopus es un primate neotropical, endémico y monotípico de Colombia, con escasos estudios sobre su anatomía, cuya morfología humeral permanece desconocida siendo un elemento fundamental para la locomoción cuadrúpeda de este animal arbóreo. El objectivo del presente estudio fue describir la anatomía macroscópica y la función de los relieves óseos del húmero del titi gris Saguinus leucopus. Se tomaron como base del estudio ocho especímenes fijados con formalina al 10% y de ellos se extrajeron sus húmeros, describiendo las principales funciones de los relieves óseos, como fijaciones musculares y canalizaciones neurovasculares. Los variados relieves anatómicos del húmero del titi gris presentan una disposición morfológica coincidente con sus hábitos de locomoción cuadrúpeda arbórea.

The Saguinus leucopus is a neotropical primate, endemic and monotypic of Colombia, with few studies reporting its anatomy. The humeral morphology for this species remains unknown and is a key element for the quadruped locomotion of this arboreal animal. The objective of the present study is to describe the gross anatomy and function of the humerus bone in the White-footed tamarin (Saguinus leucopus). The study was based on eight specimens, fixed in 10% formalin and from which we extracted the humeri, describing the main features of the bony prominences, such as muscle attachments and neurovascular pipes. The various anatomical contours of the humerus of Saguinus leucopus exhibit morphological disposition, matching their arboreal quadrupedal and locomotion habits.

Morphology of sympathetic chain in Saguinus niger.

Saguinus niger popularly known as Sauim, is a Brazilian North primate. Sympathetic chain investigation would support traumatic and/or cancer diagnosis which are little described in wild animals. The aim of this study was to describe the morphology and distribution of sympathetic chain in order to supply knowledge for neurocomparative research. Three female young animals that came death by natural causes were investigated. Animals were fixed in formaldehyde 10% and dissected along the sympathetic chain in neck, thorax and abdomen. Cranial cervical ganglion was located at the level of carotid bifurcation, related to carotid internal artery. In neck basis the vagosympathetic trunk divides into the sympathetic trunk and the parasympathetic vagal nerve. Sympathetic trunk ran in dorsal position and originated the stellate ganglia, formed by the fusion of caudal cervical and first thoracic ganglia. Vagal trunk laid ventrally to heart and formed the cardiac plexus. In abdomen, on the right side, were found the celiac ganglion and cranial mesenteric ganglion; in the left side these ganglia were fusioned into the celiac-mesenteric ganglion displaced closely to the celiac artery. In both sides, the caudal mesenteric ganglion was located near to the caudal mesenteric artery.