Quantifying the relationship between bone and soft tissue measures within the rhesus macaques of Cayo Santiago.

OBJECTIVES: Interpretations of the primate and human fossil record often rely on the estimation of somatic dimensions from bony measures. Both somatic and skeletal variation have been used to assess how primates respond to environmental change. However, it is unclear how well skeletal variation matches and predicts soft tissue. Here, we empirically test the relationship between tissues by comparing somatic and skeletal measures using paired measures of pre- and post-mortem rhesus macaques from Cayo Santiago, Puerto Rico. MATERIALS AND METHODS: Somatic measurements were matched with skeletal dimensions from 105 rhesus macaque individuals to investigate paired signals of variation (i.e., coefficients of variation, sexual dimorphism) and bivariate codependence (reduced major axis regression) in measures of: (1) limb length; (2) joint breadth; and (3) limb circumference. Predictive models for the estimation of soft tissue dimensions from skeletons were built from Ordinary Least Squares regressions. RESULTS: Somatic and skeletal measurements showed statistically equivalent coefficients of variation and sexual dimorphism as well as high epiphyses-present ordinary least square (OLS) correlations in limb lengths (R2 >0.78, 0.82), joint breadths (R2 >0.74, 0.83) and, to a lesser extent, limb circumference (R2 >0.53, 0.68). CONCLUSION: Skeletal measurements are good substitutions for somatic values based on population signals of variation. OLS regressions indicate that skeletal correlates are highly predictive of somatic dimensions. The protocols and regression equations established here provide a basis for reliable reconstruction of somatic dimension from catarrhine fossils and validate our ability to compare or combine results of studies based on population data of either hard or soft tissue proxies.

Head circumference at birth and postnatal growth trajectory in vulnerable groups from Argentina.

OBJECTIVES: To investigate the association between the anthropometric status at birth and brain and bone growth during the first year of life. According to the brain-sparing hypothesis, we expect catch-up to be faster in head circumference (HC) than in body length. METHODS: This is a longitudinal design that included Argentinian infants under 12 months of age with at least three anthropometric records. We classified study participants into four growth status categories according to z-scores for HC (HCZ) and length (LAZ) at birth, with z-score = -2 as a threshold. We used the Count model to describe growth trajectories in HC and length in the first year of life according to the growth status at birth. Recovery indicator for HC and length was taken as the time until the predicted growth trajectory surpassed the threshold curve predicted by z-score = -2 for age. RESULTS: Growth models included 3399 infants. There were significant differences in the growth parameters between groups in all cases (p < 0.05). Within the group with a low HCZ and a low LAZ at birth, HC recovery was faster than length. In the case of a low z-score for only one of the variables, newborns with a low HCZ recovered faster than individuals born with a low LAZ. CONCLUSIONS: The postnatal growth pattern in HC and length is associated with the growth status of HC and length at birth. As we hypothesized, the fastest postnatal recovery occurs for HC in cases of intrauterine delayed growth.

The effects of the industrial transition on lower limb bone structure: A comparison of the inhabitants of Pecos Pueblo and present-day Indigenous peoples of New Mexico.

OBJECTIVES: Comparisons between Indigenous peoples over time and within a particular geographic region can shed light on the impact of environmental transitions on the skeleton, including relative bone strength, sexual dimorphism, and age-related changes. Here we compare long bone structural properties of the inhabitants of the late prehistoric-early historic Pecos Pueblo with those of present-day Indigenous individuals from New Mexico. MATERIALS AND METHODS: Femora and tibiae of 126 adults from Pecos Pueblo and 226 present-day adults were included in the study. Cross-sectional diaphyseal properties-areas and second moments of area-were obtained from past studies of the Pecos Pueblo skeletal sample, and from computed tomography scans of recently deceased individuals in the present-day sample. RESULTS: Femora and tibiae from Pecos individuals are stronger relative to body size than those of present-day Indigenous individuals. Present-day individuals are taller but not wider, and this body shape difference affects cross-sectional shape, more strongly proximally. The tibia shows anteroposterior strengthening among Pecos individuals, especially among males. Sexual dimorphism in midshaft bone shape is stronger within the Pecos Pueblo sample. With aging, Pecos individuals show more medullary expansion but also more subperiosteal expansion than present-day individuals, maintaining bone strength despite cortical thinning. DISCUSSION: Higher activity levels, carried out over rough terrain and throughout adult life, likely explain the relatively stronger lower limb bones of the Pecos individuals, as well as their greater subperiosteal expansion with aging. Greater sexual dimorphism in bone structure among Pecos individuals potentially reflects greater gender-based differences in behavioral patterns.

Bioanthropological analysis of human remains from the archaic and classic period discovered in Puyil cave, Mexico.

OBJECTIVES: Determine the geographic place of origin and maternal lineage of prehistoric human skeletal remains discovered in Puyil Cave, Tabasco State, Mexico, located in a region currently populated by Olmec, Zoque and Maya populations. MATERIALS AND METHODS: All specimens were radiocarbon (14C) dated (beta analytic), had dental modifications classified, and had an analysis of 13 homologous reference points conducted to evaluate artificial cranial deformation (ACD). Following DNA purification, hypervariable region I (HVR-1) of the mitogenome was amplified and Sanger sequenced. Finally, Next Generation Sequencing (NGS) was performed for total DNA. Mitochondrial DNA (mtDNA) variants and haplogroups were determined using BioEdit 7.2 and IGV software and confirmed with MITOMASTER and WebHome softwares. RESULTS: Radiocarbon dating (14C) demonstrated that the inhabitants of Puyil Cave lived during the Archaic and Classic Periods and displayed tabular oblique and tabular mimetic ACD. These pre-Hispanic remains exhibited five mtDNA lineages: A, A2, C1, C1c and D4. Network analysis revealed a close genetic affinity between pre-Hispanic Puyil Cave inhabitants and contemporary Maya subpopulations from Mexico and Guatemala, as well as individuals from Bolivia, Brazil, the Dominican Republic, and China. CONCLUSIONS: Our results elucidate the dispersal of pre-Hispanic Olmec and Maya ancestors and suggest that ACD practices are closely related to Olmec and Maya practices. Additionally, we conclude that ACD has likely been practiced in the region since the Middle-Archaic Period.

Early anthropoid primates: New data and new questions.

Although the evolutionary history of anthropoid primates (monkeys, apes, and humans) appears relatively well-documented, there is limited data available regarding their origins and early evolution. We review and discuss here the earliest records of anthropoid primates from Asia, Africa, and South America. New fossils provide strong support for the Asian origin of anthropoid primates. However, the earliest recorded anthropoids from Africa and South America are still subject to debate, and the early evolution and dispersal of platyrhines to South America remain unclear. Because of the rarity and incomplete nature of many stem anthropoid taxa, establishing the phylogenetic relationships among the earliest anthropoids remains challenging. Nonetheless, by examining evidence from anthropoids and other mammalian groups, we demonstrate that several dispersal events occurred between South Asia and Afro-Arabia during the middle Eocene to the early Oligocene. It is possible that a microplate situated in the middle of the Neotethys Ocean significantly reduced the distance of overseas dispersal.

Methodological Proposal for the Adequate Use of the Osteotechnics Technique / Propuesta Metodológica para el uso Adecuado de la Técnica Osteotécnica

SUMMARY: Osteotechnics is one of the different anatomical preservation techniques and can be defined as the technique designed to prepare, clean, obtain and preserve bone structures that can be used in the teaching, museographic or research field. The osteotechnical technique procedure consists of the following phases: debulk and disjoint, maceration, cooking, cleaning, degreasing, bleaching, and labeling to obtain bone material. Seven phases will be explained in detail, as well as the materials, instruments, quantities of the substances used, and the time required to obtain human bone material. We consider that this article can serve as a guide, given that all the experimentation was carried out with human biological material. This methodological proposal could be consolidated and established based on the experience acquired during the creation of the contemporary skeletal collection of the department of innovation in human biological material (DIMBIH). Therefore, the purpose of our proposal is to provide tools that facilitate the work of those who carry out this work and fundamentally to avoid irreversible or irreparable damage to the osteological material, since it is of great value and difficult to acquire for disciplines as anatomy, veterinary, physical and forensic anthropology, medicine, dentistry and biology.

La osteotecnia es una de las técnicas diferentes de conservación anatómica y puede definirse como la técnica destinada a preparar, limpiar, obtener y conservar estructuras óseas que pueden ser utilizadas en el ámbito docente, museográfico o de investigación. El procedimiento de la técnica osteotécnica consta de las siguientes fases: descarnado y desarticulado, maceración, cocción, limpieza, desengrase, blanqueo y marcaje para la obtención de material óseo. Se explicarán en detalle siete fases, así como los materiales, instrumentos, cantidades de las sustancias utilizadas y el tiempo necesario para obtener material óseo humano. Consideramos que este artículo puede servir de guía, dado que toda la experimentación se realizó con material biológico humano. Esta propuesta metodológica pudo consolidarse y establecerse a partir de la experiencia adquirida durante la creación de la colección esquelética contemporánea del Departamento de Innovación en Material Biológico Humano (DIMBIH). Por lo tanto, el propósito de nuestra propuesta es brindar herramientas que faciliten el trabajo de quienes realizan este trabajo y fundamentalmente evitar daños irreversibles o irreparables en el material osteológico, ya que es de gran valor y difícil adquisición para las disciplinas como la anatomía, veterinaria, antropología física y forense, medicina, odontología y biología.

Antropología Física en función de las ciencias médicas: una necesidad de estos tiempos / Physical anthropology for medical sciences: a need in current times

Introducción: El sistema de conocimientos de Antropología Física responde a especialidades médicas como la Anatomía Humana y la Medicina Legal. En Cuba estas especialidades médicas no cuentan con la profundidad y superación profesional adecuada que permita el uso práctico de estos conocimientos. Objetivo: Caracterizar el entrenamiento de posgrado "Osteología y Odontología en función de la identificación humana", realizado en la Universidad de Ciencias Médicas de Matanzas entre enero y marzo de 2020. Métodos: Estudio observacional, descriptivo y de corte transversal. La población estuvo compuesta por 25 cursistas, especialistas en Medicina Legal y Anatomía Humana. Se consideraron variables como programa de estudio, categoría docente de los participantes, satisfacción con su desarrollo y resultados de la promoción docente. Para las indagaciones empíricas se aplicó la técnica de PNI como parte de la valoración general del curso. Resultados: El curso se impartió durante 56 horas en 7 semanas. Como parte de sus logros se realizó la clasificación y caracterización antropológica de una parte de la osamenta de la Osteoteca de la Universidad de Ciencias Médicas de Matanzas, así como la ampliación de esta mediante una sección de Antropología Física que incorporó seis cadáveres completos caracterizados antropológicamente. Conclusiones: Este entrenamiento permitió adiestrar y actualizar a los cursistas sobre la identificación humana, a partir del estudio de los restos óseos referentes a la expresión cualitativa y cuantitativa de los caracteres morfológicos, que responden a las necesidades de la práctica docente en anatomía y la asistencia médico legal(AU)

Introduction: The knowledge system of Physical Anthropology responds to medical specialties such as Human Anatomy and Legal Medicine. In Cuba, these medical specialties do not have adequate depth and professional improvement that allows the practical use of this knowledge. Objective: To characterize the training about osteology and dental medicine in view of human identification, carried out at the University of Medical Sciences of Matanzas between January and March 2020. Methods: Observational, descriptive and cross-sectional study. The population consisted of 25 trainees, specialists in Legal Medicine and Human Anatomy. Some variables were considered, such as study program, teaching category of the participants, satisfaction with their development and results of teaching promotion. For the empirical inquiries, the positive-negative-interesting technique was applied as part of the general assessment of the course. Results: The course lasted 56 hours distributed in seven weeks. As part of its achievements, the anthropological classification and characterization of a part of the materials from the bone collection of the University of Medical Sciences of Matanzas was carried out, as well as its expansion through a physical anthropology section that incorporated six complete corpses anthropologically characterized. Conclusions: This training allowed to train and update the students on human identification, based on the study of bone remains referring to the qualitative and quantitative expression of morphological characters, which respond to the needs of teaching practice in Anatomy, as well as in legal-medical assistance(AU)

Quinoa, potatoes, and llamas fueled emergent social complexity in the Lake Titicaca Basin of the Andes.

The Lake Titicaca basin was one of the major centers for cultural development in the ancient world. This lacustrine environment is unique in the high, dry Andean altiplano, and its aquatic and terrestrial resources are thought to have contributed to the florescence of complex societies in this region. Nevertheless, it remains unclear to what extent local aquatic resources, particularly fish, and the introduced crop, maize, which can be grown in regions along the lakeshores, contributed to facilitating sustained food production and population growth, which underpinned increasing social political complexity starting in the Formative Period (1400 BCE to 500 CE) and culminating with the Tiwanaku state (500 to 1100 CE). Here, we present direct dietary evidence from stable isotope analysis of human skeletal remains spanning over two millennia, together with faunal and floral reference materials, to reconstruct foodways and ecological interactions in southern Lake Titicaca over time. Bulk stable isotope analysis, coupled with compound-specific amino acid stable isotope analysis, allows better discrimination between resources consumed across aquatic and terrestrial environments. Together, this evidence demonstrates that human diets predominantly relied on C3 plants, particularly quinoa and tubers, along with terrestrial animals, notably domestic camelids. Surprisingly, fish were not a significant source of animal protein, but a slight increase in C4 plant consumption verifies the increasing importance of maize in the Middle Horizon. These results underscore the primary role of local terrestrial food resources in securing a nutritious diet that allowed for sustained population growth, even in the face of documented climate and political change across these periods.

Population level comparisons in central Mexico using cranial nonmetric traits.

OBJECTIVES: We study the genetic diversity between Classic Teotihuacan and its neighboring towns trying to understand how far or close they are at the genetic level. MATERIALS AND METHODS: We use cranial nonmetric traits to study a sample of 280 adult skulls from archaeological sites running from the late Preclassic to the early Postclassic. Samples of Classic Teotihuacan were studied for La Ventilla and San Sebastián Xolalpan neighbors. For the Epiclassic period, samples from Xaltocan, Toluca valley, Mogotes and Xico were used. For the Preclassic and Postclassic samples from Xico were also used. We used a parametric bootstrap for the mean measure of divergence for the statistical analysis. RESULTS: Samples from Xico have small biodistance from Preclassic to Postclassic. Samples from Los Mogotes differ depending on the functional context of deposition, with individuals from household burials (funerary) differing from non-funerary, ceremonial interments and exhibiting affinities to Epiclassic samples from Toluca valley. Epiclassic populations from Xaltocan vary significantly from any samples analyzed. Samples from Classic period Teotihuacan vary considerably among them but form a separate genetic group from all the other populations under study. CONCLUSIONS: The great biodistance separation among Classic Teotihuacan and its neighbor villages of central Mexico let us conclude that, contrary from the classical idea that those villages were confirmed by the inhabitants of Teotihuacan's collapse: They indeed remain as separate populations by themselves.

Associations between fecal cortisol and biparental care in a pair-living primate.

OBJECTIVES: We quantified variation in fecal cortisol across reproductive periods in Azara's owl monkeys (Aotus azarae) to examine physiological mechanisms that may facilitate biparental care. Specifically, we evaluated evidence for the explanation that owl monkeys have hormonal mechanisms to mobilize energy during periods when each sex is investing heavily in reproduction, that is, the gestation period for females and the infant care period for males. MATERIALS AND METHODS: Between 2011 and 2015, we monitored 10 groups of Azara's owl monkeys from a wild population in Formosa, Argentina and collected fecal samples from 26 adults (13 males, 13 females). Using enzyme-linked immunosorbent assays, we quantified fecal cortisol as a proxy for evaluating stress responses, including energetic demands, on both sexes during periods of reproduction and parental care. RESULTS: Male cortisol was lowest during periods when they were caring for young infants (<3 months) compared with periods with older infants or no infant. Female cortisol was elevated during gestation compared with other periods. Mean fecal cortisol in both males and females was lower when an infant was present compared with when females were gestating. DISCUSSION: Our results do not support the hypothesis that owl monkey males have elevated fecal cortisol during periods when they need to mobilize energy to provide intensive infant care. Our findings are also inconsistent with the Maternal Relief hypothesis. However, results from studies measuring fecal cortisol must be interpreted with care and alternative explanations, such as seasonal fluctuations in diet and thermoenergic demands, should be considered when drawing conclusions.

Investigating genetic diversity in admixed populations from Ecuador.

OBJECTIVES: According to demographic history, Ecuador has experienced shifts in its Native American populations caused by European colonization and the African slave trade. The continuous admixture events among Europeans, Native Americans, and Africans occurred differently in each region of the country, producing a stratified population. Thus, the aim of this study was to investigate the level of genetic substructure in the Ecuadorian Mestizo population. MATERIALS AND METHODS: A total of 377 male and 209 female samples were genotyped for two sets of X-chromosomal markers (32 X-Indels and 12 X-STRs). Population analyses performed included Hardy-Weinberg equilibrium tests, LD analysis, PCA, pairwise FST s, and AMOVA. RESULTS: Significant levels of LD were observed between markers separated by distances of less than 1 cM, as well as between markers separated by distances varying from 10.891 to 163.53 cM. Among Ecuadorian regions, Amazonia showed the highest average R2 value. DISCUSSION: When X-chromosomal and autosomal differentiation values were compared, a sex-biased admixture between European men and Native American and African women was revealed, as well as between African men and Native American women. Moreover, a distinct Native American ancestry was discernible in the Amazonian population, in addition to sex-biased gene flow between Amazonia and the Andes and Pacific coast regions. Overall, these results underline the importance of integrating X chromosome information to achieve a more comprehensive view of the genetic and demographic histories of South American admixed populations.

Population history of Brazilian south and southeast shellmound builders inferred through dental morphology.

OBJECTIVE: The Southeast and South Coast of Brazil was inhabited during most of the Holocene by shellmound builders. Although there are cultural differences in the archaeological record between regions, it is still debatable how these differences may relate to different population histories. Here, we contribute to this discussion by exploring dental morphological affinities between several regional series. MATERIALS AND METHODS: Dental morphology of 385 individuals from 14 archaeological sites was analyzed using the Arizona State University Dental Anthropology System. Fifteen traits were used to explore morphological affinities among series through Euclidean distance, Mean Measure of Divergence, and Principal Component Analysis. Mantel matrix correlation and partial correlation tests were used to examine the association between biological, geographic, and chronological distances. RESULTS: Morphological affinities show that ceramic and nonceramic South Coast groups cluster and differ from most Southeast series. In contrast, Southeast coastal and riverine groups display high morphological variance, showing less biological coherence among them. These biological distances between regions are partially explained by geography, but not by chronology. CONCLUSIONS: The results support that these coastal populations were low-mobility groups. Although interactions between individuals of different regions likely existed, gene flow occurred mostly among individuals from local or adjacent areas. The introduction of ceramic in the South Coast is not associated with changes in dental morphology patterns, suggesting its adoption is not exclusively associated with the arrival of different biological groups. Southeast coastal and riverine groups show high phenotypic diversity, suggesting a different history of human occupation and cultural development than observed in the South Coast.

Temporal, spatial and gender-based dietary differences in middle period San Pedro de Atacama, Chile: A model-based approach.

To explore the possible emergence and lived consequences of social inequality in the Atacama, we analyzed a large set (n = 288) of incredibly well preserved and contextualized human skeletons from the broad Middle Period (AD 500-1000) of the San Pedro de Atacama (Chile) oases. In this work, we explore model-based paleodietary reconstruction of the results of stable isotope analysis of human bone collagen and hydroxyapatite. The results of this modeling are used to explore local phenomena, the nature of the Middle Period, and the interaction between local situations and the larger world in which the oases were enmeshed by identifying the temporal, spatial, and biocultural correlates and dimensions of dietary difference. Our analyses revealed that: 1) over the 600-year period represented by our sample, there were significant changes in consumption patterns that may evince broad diachronic changes in the structure of Atacameño society, and 2) at/near 600 calAD, there was a possible episode of social discontinuity that manifested in significant changes in consumption practices. Additionally, while there were some differences in the level of internal dietary variability among the ayllus, once time was fully considered, none of the ayllus stood out for having a more (or less) clearly internally differentiated cuisine. Finally, sex does not appear to have been a particularly salient driver of observed dietary differences here. While we do not see any de facto evidence for complete dietary differentiation (as there is always overlap in consumption among individuals, ayllus, and time periods, and as isotopic analysis is not capable of pinpointing different foods items or preparations), there are broad aspects of dietary composition changing over time that are potentially linked to status, and foreignness. Ultimately, these stand as the clearest example of what has been termed "gastro-politics," potentially tied to the emergence of social inequality in the San Pedro oases.

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.

Migration and maize in the Virú Valley: Understanding life histories through multi-tissue carbon, nitrogen, sulfur, and strontium isotope analyses.

OBJECTIVES: Stable isotope analysis can provide crucial insight into the function and development of early state-level societies on the north coast of Peru. MATERIALS AND METHODS: Multi-tissue (bone collagen, tooth enamel, hair, nail, skin, and tendon) stable isotope analyses (carbon, nitrogen, sulfur, and strontium) were conducted for 13 individuals from the lower Virú Valley. RESULTS: Non-seasonal changes in a predominantly C4 -based terrestrial diet, with minimal inputs of marine foods were identified. One individual (Burial 5), however, had a stable isotope signature unlike any previously found on the north coast of Peru, indicating both a large contribution of C3 -terrestrial resources to their diet and an 87 Sr/86 Sr value suggestive of highland residence during childhood. DISCUSSION: This research provides the first strong stable isotope evidence of a highland individual within a coastal burial in northern Peru, new insight into the ritual killing event at Huaca Santa Clara during the late middle horizon and supporting evidence of the importance of C4 terrestrial resources to the developing Virú polity during the early intermediate period.

Genetic diversity, structure, and admixture in Mayans from Guatemala and Mexico based on 15 short tandem repeats.

OBJECTIVE: To analyze the genetic origin, relationships, structure, and admixture in Mayan Native American groups from Guatemala and Mexico based on 15 autosomal short tandem repeats (STRs) loci commonly used in human identification (HID). METHODS: We genotyped 513 unrelated Mayan samples from Guatemala based on 15 STR loci (AmpFlSTR® Identifiler kit). Moreover, we included 4408 genotypes previously reported, as following: Mayas from Guatemala and Mexico (n = 1666) and from Latin American, European, and African (n = 2742) populations. Forensic parameters, genetic distances, admixture, and population structure were assessed. RESULTS: Forensic parameters of the 15 STRs in different Mayan groups from Guatemala were reported. Low (Fst = 0.78%; p = 0.000) and non-significant differentiation (Fst = 1.8%; p = 0.108) were observed in Mayas from Guatemala and Mexico, respectively. The relative homogeneity observed among Mayan groups supported theories of extensive pre-Columbian gene flow and trade throughout the Mayan Empire. The distribution of the three Native American ancestries among these Mayan groups did not support the presumable Guatemalan origin of Tojolabal and Lacandon people (South, Mexico). The nonsignificant differentiation between Ladinos and Mayas suggests a relative panmixia in Guatemala. Mestizos from southeastern Mexico and Guatemala constitute a core of Native American ancestry in Latin America related to the Mayan Empire in Central America. CONCLUSIONS: The higher European admixture and homogeneity in Mexican Mayas of the Yucatan Peninsula suggest more intensive post-Columbian gene flow in this region than in Guatemalan Mayas.

Female reproductive energetics in mantled howler monkeys (Alouatta palliata): A follow-up study.

OBJECTIVE: Reproduction entails several challenges to primate females, among which energetic costs are remarkable at certain stages of the reproductive cycle. Still, females may use behavioral and physiological strategies to cope with those challenges. We had previously reported covariation between female energetic condition through the reproductive cycle and time-budget adjustments in mantled howler monkeys (Alouatta palliata). Accordingly, we suggested that behavioral flexibility allowed coping with the energetic challenges of reproduction. Subsequent evidence from the same population, however, suggested otherwise, so we performed a follow-up study on the variation in female reproductive energetics based on a larger sample of females. METHODS: We studied 48 free-ranging adult females at Los Tuxtlas (Mexico). We assessed energy balance via urinary C-peptide concentrations (2717 urine samples), behavioral energy intake and expenditure (5728 sampling hours), and physiological energy expenditure via fecal triiodothyronine metabolites (fTH3; 3138 fecal samples). RESULTS: We found that energy balance varied among reproductive states: (a) cycling was a period of low C-peptide concentrations; (b) the highest C-peptide concentrations occurred during gestation; and (c) the beginning of lactation marked a notable decrease in C-peptide concentrations, which then improved at mid-lactation to again decline at lactation offset. These peaks and valleys in energy balance did not seem to be associated with variation in energy acquisition but were rather mirrored by activity levels and fTH3 during lactation. DISCUSSION: Energy balance was not preserved through the reproductive cycle, supporting previous contentions that the reproductive performance of female mantled howler monkeys may be energetically constrained. The contrast between these and results that we have previously reported, highlights the importance of conducting follow-up studies to continually improve our understanding of the reproductive energetics of primate females.

Postpartum amenorrhea duration by sex of the newborn in two natural fertility populations.

OBJECTIVES: Postpartum amenorrhea (PA) affects the length of interbirth intervals and thus is intimately related to human life history strategies. PA duration appears to be influenced by maternal energetic status. In humans, as in other mammals, sons are costlier than daughters. Thus, we hypothesize that, in energetically constrained environments, a newborn's sex should be associated with PA duration. METHODS: We analyzed data from two natural fertility populations in which mothers have differing energy budgets: Qom women (n = 121) from a periurban village in Argentina, who have a comparatively calorically dense diet and are sedentary (prepregnancy mean BMI = 24.8 ± 4.5 kg/m2 in 1997), and agropastoral Kaqchikel Maya women (n = 88), who have a comparatively calorically restricted diet and high physical activity levels (mean BMI = 21.8 ± 3.7 kg/m2 ). We predict that (a) mothers of sons exhibit longer PA duration than mothers of daughters and (b) this association between offspring sex and PA duration is stronger in the Maya, who have smaller energy budgets. RESULTS: Maya mothers with sons exhibited estimated mean and median PA durations that were 1.34 times the estimated mean and median PA duration of mothers with daughters (p = 0.02). Among the Qom, mean, and median PA duration did not differ significantly in relation to offspring sex (p = 0.94). CONCLUSIONS: Maya mothers with sons exhibited longer PA duration than those with daughters. This phenomenon was not observed in the well-nourished Qom, possibly due to "buffering" effects from larger energy budgets. Offspring sex may influence birth spacing and maternal life history strategies in energetically constrained environments.

Lone males: Solitary and group-living male howler monkey (Alouatta palliata) behavioral ecology in a Costa Rican rainforest.

OBJECTIVES: Many group-living primate species have evolved the capacity for some individuals to live alone for part of their lives, but this solitary life stage has rarely been the subject of focused research. The mantled howler monkey (Alouatta palliata) is a social primate species with bisexual dispersal that lives in mixed-sex groups with low male-to-female sex ratios. Consequently, males often spend a long period of their lives as solitary individuals. This study compares the tree use, feeding, and long-distance vocalization behavior of solitary and group-living mantled howler monkey males living within a fragmented rainforest in Costa Rica, La Suerte Biological Research Station. Based on differences in competitive ability between solitary and group-living males, we predicted that lone males would be found in significantly smaller feeding and resting trees, consume more low-quality foods, and produce shorter howling bouts made at lower rates than group-living males. MATERIALS AND METHODS: We collected data on tree use and feeding during 30-min focal samples on male focal animals, recording data at 2-min intervals. We measured the trees in which the monkeys fed and rested for two or more intervals, and recorded the plant parts consumed. We recorded howling behavior using all-occurrences sampling. RESULTS: Lone males used significantly smaller feeding and resting trees, consumed more low-quality foods, and howled at lower rates but had longer howling bouts triggered by anthropogenic noise more than group-living males. DISCUSSION: Our results demonstrate that lone males differ in their behavioral ecology compared to group-living males, thus improving understanding of the solitary male life stage in primates.

Newborn anthropometry, maternal capital, and altitude in the highland population from the province of Jujuy, Argentina.

OBJECTIVE: To analyze variability in newborn (NB) anthropometry among Jujenean NBs as a function of geographic altitude (500 m to ≈4000 masl), maternal anthropometry and other maternal characteristics within the maternal capital framework. MATERIALS AND METHODS: Data obtained from 41,371 mother/child pairs recorded in the Jujuy Perinatal Information System (SIP) between 2009 and 2014, including: NB and maternal weight, length/height and BMI; gestational age (corrected); maternal age, educational level, nutritional status, and marital status; birth interval; and planned pregnancy. Based on the declared place of residence, the prevalence of unsatisfied basic needs (% UBN) was determined and the data was split into two altitudinal groups: highlands (HL, >2500 masl) and lowlands (LL, <2500 masl). ANOVA, Chi-squared and Pearson tests were applied as needed. Statistical associations between the response variables-NB weight, length and BMI-and maternal and environmental variables were tested using a Generalized Additive Mixed Model (GAMM). RESULTS: All NB and maternal anthropometric variables were lower in HL compared to LL; they also presented negative correlations with altitude, except NB length. Apart from gestational age and birth interval, HL and LL presented statistically significant differences in all study variables. GAMM results showed that maternal anthropometry was the main influence on NB weight and length. DISCUSSION: Of all the maternal capital features examined, only maternal anthropometric variables were found to protect offspring against the negative impact of HL environments.