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).

Multinucleate parietal cells and cytoplasmic inclusion bodies in the gastric epithelium of callitrichids.

Inclusion bodies (IBs) and multinucleate cells can be associated with viral infections; however, IBs and multinucleate cells have been described in normal tissue and with non-viral disease processes in multiple species. We examined fundic stomach from 50 callitrichids histologically for bi- and multinucleate parietal cells and cytoplasmic IBs in gastric epithelial cells. Callitrichids represented included 6 genera: Saguinus (4 spp.), Leontopithecus (1 sp.), Mico (3 spp.), Cebuella (1 sp.), Callithrix (1 sp.), Callimico (1 sp.), and 13 unspecified marmosets. Gastric epithelial IBs were present in 46 of 47 (98%) of the callitrichids from which the stomach was sufficiently well preserved to identify IBs. Cytoplasmic IBs were identified in gastric surface pit epithelial cells (43 of 44, 98%), mucous neck cells (43 of 44, 98%), parietal cells (43 of 44, 98%), and chief cells (43 of 44, 98%). The IBs were eosinophilic, ovoid, round, elongate, or variably indented, sometimes slightly refractile, and 1-6 × 1-13 µm. IBs were sometimes perinuclear and molded around the nucleus. Electron microscopy of the gastric epithelium of one marmoset indicated that IBs were composed of intermediate filaments. The IBs did not stain with immunohistochemical markers for cytokeratin AE1/AE3 or vimentin. Binucleate parietal cells were found in 49 of 50 (98%) callitrichids, and multinucleate parietal cells were observed in 40 of 49 (82%) callitrichids. Gastric epithelial cytoplasmic IBs and bi- and multinucleate parietal cells are likely a normal finding in callitrichids, and, to our knowledge, have not been reported previously.

Myological variation in the forearm anatomy of Callitrichidae and Lemuridae.

The anatomy of the primate forearm is frequently investigated in terms of locomotor mode, substrate use, and manual dexterity. Such studies typically rely upon broad, interspecific samples for which one or two representative taxa are used to characterize the anatomy of their genus or family. To interpret variation between distantly related taxa, however, it is necessary to contextualize these differences by quantifying variation at lower hierarchical levels, that is, more fine-grained representation within specific genera or families. In this study, we present a focused evaluation of the variation in muscle organization, integration, and architecture within two speciose primate families: the Callitrichidae and Lemuridae. We demonstrate that, within each lineage, several muscle functional groups exhibit substantial variation in muscle organization. Most notably, the digital extensors appear highly variable (particularly among callitrichids), with many unique configurations represented. In terms of architectural variables, both families are more conservative, with the exception of the genus Callimico-for which an increase is observed in forearm muscle mass and strength. We suggest this reflects the increased use of vertical climbing and trunk-to-trunk leaping within this genus relative to the more typically fine-branch substrate use of the other callitrichids. Overall, these data emphasize the underappreciated variation in forearm myology and suggest that overly generalized typification of a taxon's anatomy may conceal significant intraspecific and intrageneric variation therein. Thus, considerations of adaptation within the forearm musculature should endeavor to consider the full range of anatomical variation when making comparisons between multiple taxa within an evolutionary context.

Taxonomic diversity of Cebuella in the western Amazon: Molecular, morphological and pelage diversity of museum and free-ranging specimens.

OBJECTIVES: We investigated the diversity of the pygmy marmoset, Cebuella pygmaea, by comparing genetic, morphological and pelage traits of animals from Peru and Ecuador. MATERIALS AND METHODS: We extracted DNA from museum specimen osteocrusts and from fecal samples collected from free-ranging individuals. We sequenced the mtDNA cytochrome b gene and the control region from samples collected at 13 different sites and used Bayesian inference and Maximum Likelihood to identify distinct clades. We took measurements of the crania of a subset of these specimens (n = 26) and ran a logistic regression to determine if any of the cranial measurements (n = 22) could predict a specimen's clade. In addition, we examined the pelage patterns of the museum specimens and photographs taken of free-ranging individuals and divided them into pelage types based on coloration of the underbelly. RESULTS: We identified two divergent clades, and two distinct groups with clear geographic boundaries within one of those clades. Two measurements of the zygomatic bone perfectly predicted a given individual's mtDNA clade. We found four distinct pelage patterns in our samples, but these patterns are variable within clades and among individuals within the same population. CONCLUSION: These analyses indicate that the two recognized subspecies of pygmy marmoset should be elevated to the species level (C. pygmaea and C. niveiventris) based on molecular and cranial differences but not on pelage patterns. We provide evidence on the geographic limits of the two clades and identify regions where additional sampling is required to better define the geographic distribution of the two clades.

Phenotypic evolution in marmoset and tamarin monkeys (Cebidae, Callitrichinae) and a revised genus-level classification.

Marmosets and tamarins (Cebidae, Callitrichinae) constitute the most species-rich subfamily of New World monkeys and one of the most diverse phenotypically. Despite the profusion of molecular phylogenies of the group, the evolution of phenotypic characters under the rapidly-emerging consensual phylogeny of the subfamily has been little studied, resulting in taxonomic proposals that have limited support from other datasets. We examined the evolution of 18 phenotypic traits (5 continuous and 13 discrete), including pelage, skull, dentition, postcrania, life-history and vocalization variables in a robust molecular phylogeny of marmoset and tamarin monkeys, quantifying their phylogenetic signal and correlations among some of the traits. At the family level, our resulting topology supports owl monkeys (Aotinae) as sister group of Callitrichinae. The topology of the callitrichine tree was congruent with previous studies except for the position of the midas group of Saguinus tamarins, which placement as sister of the bicolor group did not receive significant statistical support in both Maximum Parsimony and Bayesian Inference analyses. Our results showed that the highest value of phylogenetic signal among continuous traits was displayed by the long call character and the lowest was exhibited in the home range, intermediate values were found in characters related to osteology and skull size. Among discrete traits, pelage and osteology had similar phylogenetic signal. Based on genetic, osteological, pelage and vocalization data, we present an updated genus-level taxonomy of Callitrichinae, which recognizes six genera in the subfamily: Callimico, Callithrix, Cebuella, Mico, Leontopithecus and Saguinus. To reflect their phenotypic distinctiveness and to avoid the use of the informal "species group", we subdivided Saguinus in the subgenera Leontocebus, Saguinus and Tamarinus (revalidated here).

Quantification of Myosin Heavy Chain Isoform mRNA Transcripts in the Supraspinatus Muscle of Vertical Clinger Primates.

Vertical clinging is a specialized form of locomotion characteristic of the primate family Callitrichidae. Vertical clinging requires these pronograde primates to maintain a vertical posture, so the protraction of their forelimbs must resist gravity. Since pronograde primates usually move as horizontal quadrupeds, we hypothesized that the supraspinatus muscle of vertical clingers would present specific characteristics related to the functional requirements imposed on the shoulder area by vertical clinging. To test this hypothesis, we quantified by real-time quantitative polymerase chain reaction the mRNA transcripts of myosin heavy chain (MHC) isoforms in the supraspinatus muscle of 15 species of pronograde primates, including vertical clingers. Our results indicate that the supraspinatus of vertical clingers has a specific expression pattern of the MHC isoforms, with a low expression of the transcripts of the slow MHC-I isoform and a high expression of the transcripts of the fast MHC-II isoforms. We conclude that these differences can be related to the particular functional characteristics of the shoulder in vertical clingers, but also to other anatomical adaptations of these primates, such as their small body size.

Marmosets.

Wahab et al. introduce the marmosets, a group of peculiar New World monkeys.

Lost and found: The third molars of Callimico goeldii and the evolution of the callitrichine postcanine dentition.

This study tests the hypothesis that the third molars of Callimico goeldii represent a reversal in evolutionary tooth loss within the Callitrichinae. Loss of third molars is part of a suite of unusual characters that has been used to unite marmosets and tamarins in a clade to the exclusion of Callimico. However, molecular phylogenetic studies provide consistent support for the hypothesis that marmosets are more closely related to Callimico than to tamarins, raising the possibility that some or all of the features shared by marmosets and tamarins are homoplastic. Here, I use the binary-state speciation and extinction (BiSSE) model and a sample of 249 extant primate species to demonstrate that, given the shape of the primate phylogenetic tree and the distribution of character states in extant taxa, models in which M3 loss is constrained to be irreversible are much less likely than models in which reversals are allowed to occur. This result provides support for the idea that the last common ancestor of Callimico and marmosets was characterized by the two-molared phenotype. The M3s of Callimico therefore appear to be secondarily derived rather than plesiomorphic. This conclusion may also apply to the other apparently plesiomorphic traits found in Callimico. Hypotheses regarding the re-evolution of M3 in the callitrichine clade and the origin and maintenance of the two-molared phenotype are discussed.

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.

An investigation of ecological correlates with hand and foot morphology in callitrichid primates.

Studies of primate taxonomy and phylogeny often depend on comparisons of limb dimensions, yet there is little information on how morphology correlates and contributes to foraging strategies and ecology. Callitrichid primates are ideal for comparative studies as they exhibit a range of body size, limb proportions and diet. Many callitrichid species exhibit a high degree of exudativory, and to efficiently exploit these resources, they are assumed to have evolved morphologies that reflect a level of dependence on these resources. We tested assumptions by considering measurements of limb proportion and frictional features of the volar surfaces in preserved specimens of 25 species with relation to published life history and ecological data. The degree of exudativory and utilization of vertical substrates during foraging were found to correlate both with size and with size-corrected foot and hand dimensions. Smaller species, which engage in greater degrees of exudativory, had proportionally longer hands and feet and more curved claw-like tegulae (nails) on their digits to facilitate climbing on vertical substrates. The density of patterned ridges (dermatoglyphs) on the volar surfaces of the hands and feet is higher in more exudativorous genera, suggesting a role in climbing on vertical tree trunks during foraging. Dermatoglyph comparisons suggest that ridges on the soles and palms may facilitate food procurement by enhancing frictional grip during exudate feeding. Volar pad features corroborate taxonomic relationships described from dental morphology.

A specialized area in limbic cortex for fast analysis of peripheral vision.

In primates, prostriata is a small area located between the primary visual cortex (V1) and the hippocampal formation. Prostriata sends connections to multisensory and high-order association areas in the temporal, parietal, cingulate, orbitofrontal, and frontopolar cortices. It is characterized by a relatively simple histological organization, alluding to an early origin in mammalian evolution. Here we show that prostriata neurons in marmoset monkeys exhibit a unique combination of response properties, suggesting a new pathway for rapid distribution of visual information in parallel with the traditionally recognized dorsal and ventral streams. Whereas the location and known connections of prostriata suggest a high-level association area, its response properties are unexpectedly simple, resembling those found in early stages of the visual processing: neurons have robust, nonadapting responses to simple stimuli, with latencies comparable to those found in V1, and are broadly tuned to stimulus orientation and spatiotemporal frequency. However, their receptive fields are enormous and form a unique topographic map that emphasizes the far periphery of the visual field. These results suggest a specialized circuit through which stimuli in peripheral vision can bypass the elaborate hierarchy of extrastriate visual areas and rapidly elicit coordinated motor and cognitive responses across multiple brain systems.

Evolution of ASPM is associated with both increases and decreases in brain size in primates.

A fundamental trend during primate evolution has been the expansion of brain size. However, this trend was reversed in the Callitrichidae (marmosets and tamarins), which have secondarily evolved smaller brains associated with a reduction in body size. The recent pursuit of the genetic basis of brain size evolution has largely focused on episodes of brain expansion, but new insights may be gained by investigating episodes of brain size reduction. Previous results suggest two genes (ASPM and CDK5RAP2) associated with microcephaly, a human neurodevelopmental disorder, may have an evolutionary function in primate brain expansion. Here we use new sequences encoding key functional domains from 12 species of callitrichids to show that positive selection has acted on ASPM across callitrichid evolution and the rate of ASPM evolution is significantly negatively correlated with callitrichid brain size, whereas the evolution of CDK5RAP2 shows no correlation with brain size. Our findings strongly suggest that ASPM has a previously unsuspected role in the evolution of small brains in primates. ASPM is therefore intimately linked to both evolutionary increases and decreases in brain size in anthropoids and is a key target for natural selection acting on brain size.

Microanatomical variation of the nasal capsular cartilage in newborn primates.

The breakdown of nasal capsule cartilage precedes secondary pneumatic expansion of the paranasal sinuses. Recent work indicates the nasal capsule of monkeys undergoes different ontogenetic transformations regionally (i.e., ossification, persistence as cartilage, or resorption). This study assesses nasal capsule morphology at the perinatal age in a taxonomically broad sample of non-human primates. Using traditional histochemical methods, osteopontin immunohistochemistry and tartrate-resistant acid phosphatase procedure, the cartilage of the lateral nasal wall (LNC) was studied. At birth, matrix properties differ between portions of the LNC that ultimately form elements of the ethmoid bone and regions of the LNC that have no postnatal (descendant) structure. The extent of cartilage that remains in the paranasal parts of the LNC varies among species. It is fragmented in species with the greatest extent of maxillary and/or frontal pneumatic expansion. Conversely, greater continuity of the LNC is noted in newborns of species that lack maxillary and/or frontal sinuses as adults. Chondroclasts occur adjacent to elements of the ethmoid bone, along the margin of the nasal tectum, and/or along islands of cartilage that bear no signs of ossification. Chondroclasts are prevalent along remnants of the paranasal LNC in tamarin species (Leontopithecus, Saguinus), which have extensive frontal and maxillary bone pneumatization. Taken together, the morphological observations indicate that the localized loss of cartilage might be considered a critical event at the onset of secondary pneumatization, facilitated by rapid recruitment of chondro-/osteoclasts, possibly occurring simultaneously in cartilage and bone.

Ultrastructural aspects of Callithrix penicillata lingual papillae.

Callithrix penicillata belongs to the family Callitrichidae, Callithrix genus. They are basically insectivorous, but they consume fruits. The mucosa of the tongue is composed of some papillary types, revealing different levels of expertise. The present study attempted to describe the morphological and ultrastructural aspects of the dorsal surface of the C. penicillata, describing the characteristics and distribution of papillae found. Five tongues of C. penicillata (two females and three males), obtained from breeding colonies of CENP-Ananindeua-PA, died from natural causes. The material was fixed partly in a buffer solution paraformaldehyde 10% and partly in modified Karnovsky solution, divided into apex, body, and root, and then the fragments were used in light microscopy and scanning electron microscopy. The average length of the tongue of the females was 22 mm and for males 20.5 mm. Three types of papillae were described: filiform (along all tissue extension with 154 µm of diameter), fungiform (along all tissue extension with 275 µm of diameter), and vallate (just three units in caudal (dorsal) portion with 672 µm of diameter). Data analysis indicates that the distribution and ultrastructural morphology of the C. penicillata lingual papillae are some similar to other primates.

The functional morphology of the anterior masticatory apparatus in tree-gouging marmosets (Cebidae, Primates).

Although all genera of Callitrichinae feed on tree exudates, marmosets (Callithrix and Cebuella) use specialized anterior teeth to gouge holes in trees and actively stimulate exudate flow. Behavioral studies demonstrate that marmosets use large jaw gapes but do not appear to generate large bite forces (relative to maximal ability) during gouging. Nonetheless, the anterior teeth of marmosets likely experience different loads during gouging compared to nongouging platyrrhines. We use histological data from sectioned teeth, µCTs of jaws and teeth, and in vitro tests of symphyseal strength to compare the anterior masticatory apparatus in Callithrix to nongouging tamarins (Saguinus) and other cebids. We test the hypotheses that (1) marmoset anterior teeth are adapted to accommodate relatively high stresses linked to dissipating gouging forces and (2) the mandibular symphysis does not provide increased load resistance ability compared with closely related nongouging platyrrhines. Differences in decussation between Callithrix and Saguinus are greatest in the anterior teeth, suggesting an increased load resistance ability specifically in incisor and canine enamel of Callithrix. Callithrix lower incisor crowns are labiolingually thicker suggesting increased bending resistance in this plane and improved wedging ability compared with Saguinus. Anterior tooth roots are larger relative to symphyseal bone volume in Callithrix. Anterior tooth root surface areas also are larger in marmosets for their symphyseal volume, but it remains unclear whether this relative increase is an adaptation for dissipating dental stresses versus a growth-related byproduct of relatively elongated incisors. Finally, simulated jaw loading suggests a reduced ability to withstand external forces in the Callithrix symphysis. The contrast between increased load resistance ability in the anterior dentition versus relatively reduced symphyseal strength (1) suggests a complex loading environment during gouging, (2) highlights the possibility of distinct loading patterns in the anterior teeth versus the symphysis, and (3) points to a potential mosaic pattern of dentofacial adaptations to tree gouging.

Comparative microcomputed tomography and histological study of maxillary pneumatization in four species of new world monkeys: the perinatal period.

In anthropoid primates, it has been hypothesized that the magnitude of maxillary sinus growth is influenced by adjacent dental and soft tissue matrices. Relatively, little comparative evidence exists for the perinatal period when secondary pneumatization is at its earliest stages in some primates. Here, dental and midfacial variables were studied in a perinatal sample of four anthropoid primates, including three callitrichines (Leontopithecus, Saguinus, and Callithrix) and Saimiri boliviensis. In the latter species, the maxillary recess (the ontogenetic precursor to a "true" maxillary sinus) does not undergo secondary pneumatization. Using histological methods and micro-computed tomography, midfacial and dental dimensions and radiographic hydroxyapatite density of tooth cusps were measured. The distribution of osteoclasts and osteoblasts was also documented. Kruskal-Wallis's one-way analysis of variance tests indicates significant (P < 0.05) differences among groups for dental and midfacial measurements. In particular, the posterior maxillary dentition is relatively larger and more mineralized in Saimiri compared to the callitrichines. At posterior dental levels, Saimiri has the lowest palatonasal index [interdental (palatal) width/width of the nasal cavity] and highest bizygomatic-interorbital index. Distribution of osteoclasts indicates that the inferomedial surfaces of the orbits are resorptive in perinatal Saimiri, whereas, in all callitrichines, these surfaces are depository. Taken together, these findings suggest that pneumatization in Saimiri is suppressed by an inward growth trajectory of the orbits, relatively large posterior dentition, and a correspondingly compressed nasal region.

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.

The functional correlates of jaw-muscle fiber architecture in tree-gouging and nongouging callitrichid monkeys.

Common (Callithrix jacchus) and pygmy (Cebuella pygmaea) marmosets and cotton-top tamarins (Saguinus oedipus) share broadly similar diets of fruits, insects, and tree exudates. Marmosets, however, differ from tamarins in actively gouging trees with their anterior dentition to elicit tree exudates flow. Tree gouging in common marmosets involves the generation of relatively wide jaw gapes, but not necessarily relatively large bite forces. We compared fiber architecture of the masseter and temporalis muscles in C. jacchus (N = 18), C. pygmaea (N = 5), and S. oedipus (N = 13). We tested the hypothesis that tree-gouging marmosets would exhibit relatively longer fibers and other architectural variables that facilitate muscle stretch. As an architectural trade-off between maximizing muscle excursion/contraction velocity and muscle force, we also tested the hypothesis that marmosets would exhibit relatively less pinnate fibers, smaller physiologic cross-sectional areas (PCSA), and lower priority indices (I) for force. As predicted, marmosets display relatively longer-fibered muscles, a higher ratio of fiber length to muscle mass, and a relatively greater potential excursion of the distal tendon attachments, all of which favor muscle stretch. Marmosets further display relatively smaller PCSAs and other features that reflect a reduced capacity for force generation. The longer fibers and attendant higher contraction velocities likely facilitate the production of relatively wide jaw gapes and the capacity to generate more power from their jaw muscles during gouging. The observed functional trade-off between muscle excursion/contraction velocity and muscle force suggests that primate jaw-muscle architecture reflects evolutionary changes related to jaw movements as one of a number of functional demands imposed on the masticatory apparatus.

Myocardial stereology in captive Callithrix kuhlii (Callitrichidae, Primates): healthy animals versus animals affected by wasting marmoset syndrome (WMS)

This study comprised 12 hearts of Wied´s black-tufted-ear marmoset, Callithrix kuhlii (Coimbra-Filho 1985), 6 with Wasting Marmoset Syndrome (WMS) and 6 non-affected. Biometry was performed after death. After necropsy, the hearts were weighed, dissected, fixed in 10 percent formalin solution (pH 7.2), and processed for optical microscopy at 5µm sections stained with Haematoxylin-Eosin. Quantitative analysis was performed by stereological techniques. The statistical differences between the biometrical and stereological parameters were assessed by the Mann-Whitney test. The morphometric results showed that WMS causes a significant reduction in body and cardiac weights, and also in the volume density of vessels in those animals. Further studies are necessary to understand some of the results shown here.

Neste estudo, foram utilizados corações de 12 Sagui-de-Wied, Callitrhix kuhlii (Coimbra-Filho 1985), sendo 6 animais afetados pela SEP e 6 animais normais. Após a morte foi realizada a biometria seguida de necropsia. Os corações foram fixados em formol tamponado a 10 por cento, pesados e dissecados, sendo processados através de técnicas histológicas de rotina para microscopia óptica em cortes de 5µm corados por Hematoxilina-Eosina. As análises quantitativas foram feitas com o uso de técnicas estereológicas. As diferenças estatísticas entre os parâmetros biométricos e estereológicos foram avaliadas usando o test Mann-Whitney. Os resultados encontrados através da morfometria mostraram que a SEP causa uma redução significante do peso tanto corporal quanto do músculo cardíaco, e também uma redução no volume dos vasos nestes animais. Novos estudos são necessários para entender alguns dos resultados mostrados aqui.

Q-factor analysis as a tool for phylogenetic studies of morphometric data.

The statistical procedure of Q-factor analysis was applied with the aim to detect complex morphological characters, which clearly separate taxonomic groups. Since Q-factor analysis, unlike cluster analysis, does not prescribe a hierarchical grouping, the results can be interpreted phylogenetically using an outgroup comparison. The essential steps of the approach are demonstrated by an empirical study on the phylogeny of Callitrichinae. Except for some complications concerning the determination of the number of relevant factors and factor rotation, the procedure proved to be a suitable instrument for phylogenetic research.