Juveniles

Sex estimation in non-adult skeletons is crucial in bioarchaeology and forensic anthropology. It was not extensively considered in the past, mainly because it was stated that the dimorphic osteological features were difficult to identify before adulthood. Over the past few years, this statement was disproved, and the study of numerous dimorphic non-adult skeletal traits was approached. This paper presents a new methodology that evaluates the auricular surface of the non-adult ilia. Several morphological and continuous variables were recorded for 34 individuals (21 females and 13 males) aged between 7 and 18 from the Coimbra Identified Skeletons Collection (University of Coimbra, Portugal). The results show low intra and inter-observer errors for all the variables, which renders the methodology replicable. Two ratios related to the shape of the anterior area of the auricular surface offer the most dimorphic data (proportions of cases correctly assigned: 0.82 and 0.88; sexual allocation probabilities: 0.85 for both variables). A discriminant function and a logistic regression were developed, which correctly classified the 82.35 and the 88.23% of the individuals, respectively. Moreover, two qualitative variables, referred to as the overall morphology and the apex morphology, also show statistically significant differences between males and females (proportions of correct assignation: 0.82 and 0.76; sexual allocation probabilities: 0.79 and 0.76). These variables can be incorporated in a multifactorial approach together with other indicators already available in the specialised literature in order to help improve the accuracy of the results obtained. This methodological procedure has to be applied with other identified samples, including younger individuals, so as to test whether the trends presented in this context are maintained and are useful in populations from a different geographical provenience.

Temporal variation in spatial distribution by age of Phoenicopterus ruber (Phoenicopteriformes: Phoenicopteridae) in the wetlands of Yucatán, Mexico. The Caribbean Flamingo (Phoenicopterus ruber) in Mexico is distributed throughout the complex of lagoons in coastal wetlands of the Yucatan Peninsula. The species shows a tendency toward differential use of areas between juveniles and adults at different stages of their life cycle, and in different seasons. The aim of this study was to determine the most important areas where flamingos are distributed in Yucatan wetlands, and to describe temporal variations according to age and stages of their life cycle. For this, we used the records of ringed individuals sighted during the period 2010-2015. The areas with the largest numbers of individuals, by stage and season, were identified. Flamingos were recorded in 39 different areas of 43 sampled. In general, the sites with the largest number of records were Isla La Angostura and Punta Mecoh. To both juveniles and adults, areas with higher occupancy rates differed by age between the different stages of the life cycle and seasons. In the Charca Salinera Chel and Isla La Angostura ringed flamingos of almost all ages were recorded. Although already described areas (Celestún, Ría Lagartos) are certainly important, new sites hosting considerable populations at some stage of this species life cycle were detected (e.g. Humedal Progreso; Salamandra, Laguna Rosada; Xcambo). These new sites should be given more attention and important security measures and protection are recommended to all of them. It is necessary to seek new support sources for studies that determine the flamingo population's status in difficult access areas for which little information is available.