In forensic anthropology, ancestry estimation is essential in establishing the individual biological profile. The aim of this study is to present a new program—AncesTrees—developed for assessing ancestry based on metric analysis. AncesTrees relies on a machine learning ensemble algorithm, random forest, to classify the human skull. In the ensemble learning paradigm, several models are generated and co-jointly used to arrive at the final decision. The random forest algorithm creates ensembles of decision trees classifiers, a non-linear and non-parametric classification technique. The database used in AncesTrees is composed by 23 craniometric variables from 1,734 individuals, representative of six major ancestral groups and selected from the Howells’ craniometric series. The program was tested in 128 adult crania from the following collections: the African slaves’ skeletal collection of Valle da Gafaria; the Medical School Skull Collection and the Identified Skeletal Collection of 21st Century, both curated at the University of Coimbra. The first step of the test analysis was to perform ancestry estimation including all the ancestral groups of the database. The second stage of our test analysis was to conduct ancestry estimation including only the European and the African ancestral groups. In the first test analysis, 75 % of the individuals of African ancestry and 79.2 % of the individuals of European ancestry were correctly identified. The model involving only African and European ancestral groups had a better performance: 93.8 % of all individuals were correctly classified. The obtained results show that AncesTrees can be a valuable tool in forensic anthropology.

An archaeological intervention in Valle da Gafaria (Lagos, Portugal) allowed the excavation of a deposit of waste dating from the 15^th to 17^th centuries. Among discarded objects, an important amount of human skeletal remains was exhumed (N = 158 individuals). The archaeological and historical context, as well as the morphometric analysis of the skulls, led us to attribute them an African origin. While historical sources document the trade of slaves by the Portuguese since the 15^th century, so far no slave cemetery was excavated in Portugal. The study of their lives and deaths has been accomplished by historical documents. Therefore, this sample provides a unique opportunity to learn more about captive individuals who were brought to Portugal in the modern period. The present work focuses in the intentional dental modifications presented by several of these individuals. A total of 113 subjects have teeth that can be evaluated for the presence of intentional modifications. Of these, 55.8% individuals present dental modifications on their anterior dentition, 42.9% exhibiting modifications on both upper and lower teeth. The incisors were the most frequently modified teeth, followed by the canines. Both men and women as adults and sub‐adults have dental intentional modifications. In most individuals, dental modifications involved the removal of the mesial and distal angles, which is comparable with sub‐Saharan African practices. However, we cannot infer a more specific origin for these slaves only based on dental modification's type and pattern because several ethnic groups modify teeth in the same way. Copyright © 2015 John Wiley & Sons, Ltd.