What is a migrant death? An operational definition for a more accurate enumeration of migrant mortality along the US-Mexico border.

Over the last forty years an indeterminate number of persons, ranging from thousands to tens of thousands, have died along the US-Mexico border during migration, fleeing poverty, armed conflict, situations of violence, and disasters. An accurate accounting of migrant deaths along the southern US border is the first step toward an understanding of the extent and the contributing factors of these deaths. In this article, we describe a key aspect of our collaborative work aimed at developing a more representative account of migrant mortality along the southwestern US border: the determination of criteria for inclusion of specific forensic cases as "migrant." Our intention is not to propose a definition of "what is a migrant death" applicable to all contexts and situations but rather one specific to the US-Mexico border region. Our main impetus is to build and launch a web portal to track and map migrant deaths at the US-Mexico border. The criteria we have identified are based on an examination of death data collected by various agencies in the four border states (California, Arizona, New Mexico, and Texas) and at the federal level by the National Missing and Unidentified Persons System (NamUs). They include a) context of human remains discovery; b) identification media/documentation; c) geographic setting; and d) personal effects. Taken together, these criteria will facilitate our determination, case by case, of the probability that human remains found along the United States side of the border may be from a person in the context of migration.

Morphological variation among late holocene Mexicans: Implications for discussions about the human occupation of the Americas.

OBJECTIVES: Cranial morphology has previously been used to estimate phylogenetic relationships among populations, and has been an important tool in the reconstruction of ancient human dispersals across the planet. In the Americas, previous morphological studies support a scenario of people entering the Americas and dispersing from North America into South America through Meso America, making the Mexican territory the natural funnel through which biological diversity entered South America. MATERIALS AND METHODS: We explore the cranial morphological affinities of three late Holocene Mexican series, in relation to ancient and modern crania from North and South America, Australo-Melanesia, and East Asia. Morphological affinities were assessed through Mahalanobis Distances, and represented via Multidimensional Scaling and Ward's Linkage Cluster analysis. Minimum FST values were also calculated for each series. RESULTS: Our results show Mexican groups share morphological affinities with the Native American series, but do not cluster together as would be expected. The minimum FST estimates show between-group variation in the Americas is higher than the Asian or Australo-Melanesian populations, and that Mexican series have high between-group variance (FST = 0.124), compared to the geographically larger South America (FST = 0.116) and North America (FST = 0.076). DISCUSSION: These results show that the Mexican series share morphological affinities with the East Asian series, but maintains high levels of between-group variation, similar to South America. This supports the suggestion that the high phenotypic variation seen the Americas is not a result of its size, as it can be found in more constricted areas, such as the Mexican territory.