One hundred and thirty-nine skulls constituted the migrant sample, recovered from the shipwreck of 18 April 2015 in the Mediterranean Sea and housed at the Laboratory of Forensic Anthropology and Odontology (LABANOF) for identification purposes. They are currently being examined from a genetic and anthropological perspective for the best possible biological profile to be completed for comparison with future antemortem data [33 ]. Migratory status of these individuals is demonstrated by the context of retrieval. Among the remains in various stages of decomposition, many skeletonized remains were found commingled; the skulls selected are part of these commingled remains [31 (link)]. Sometimes, the crania were found anatomically connected to their respective mandibles. While sex estimations relied upon standard morphological features [34 (link)], age-at-death was estimated considering skeletal methods, with the spheno occipital and palatal sutures [35 (link)], and dental methods based on the state of eruption and development, translucency of the tooth root and periodontosis, and dental pulp regression, observed macroscopically or through X-rays [36 (link),37 (link),38 (link),39 (link),40 (link),41 (link)]. Further details are currently in the process of publication in institutional and scientific reports. Population affinity was performed based on morphological features of the cranium [42 ]. This method gives probabilities associated to four macro-categories of ancestry: African, American Indian, Asian, and European. The results showed that all crania belonged to male individuals aged between 16 and 35 years, and mainly of African origin [33 ]. It is important to mention that their “migrant” status was not estimated but already known from the context of the shipwreck. While their exact reason for migrating is not known, “there is no doubt that any person making the decision to cross the Mediterranean at the risk of his or her life has imperative reasons to do so” [43 ].
Twenty-five skulls were selected from the CAL Milano Cemetery Skeletal Collection to serve as control sample. This skeletal collection, started in 2012, is composed of unclaimed remains buried in Milanese cemetery and housed at the LABANOF [32 (link)]. In addition to being contemporary (with individuals who died in the 20th century, including 80% after 1980), the collection has the advantage of being documented, meaning that the individuals are associated to a documentation that includes sex, age-at-death, date of birth, date of death, cause of death, and pathological conditions related to it. The individuals of the CAL Milano Cemetery Skeletal Collection were primarily selected based on their ages-at-death, in order to correspond to the same age range as that of the migrants, that is, between 20 and 35 years. From this criterion, a total of 28 individuals were found in the collection. However, this young age-at-death requirement created a selective mortality bias in the sample which was considered. The non-migrant sample was therefore clearly contextualized and the limitations in inferences were clearly set in order to deal with this selectivity bias. The second selection criterion was the good preservation of the remains, specifically of the cranium and mandible; only skeletons for which the three stress markers selected could be potentially observable (i.e., preservation of the orbits and cranial vault, presence of at least half of the dentition) were selected, which resulted in the removal of three cases from the sample. These two criteria of selection (age-at-death and preservation) thus resulted in a sample constituted of 19 males and 6 females, all of Italian descent. Biological profile was only estimated for the migrant sample, since this data was already known for the cemetery sample.
Twenty-five skulls were selected from the CAL Milano Cemetery Skeletal Collection to serve as control sample. This skeletal collection, started in 2012, is composed of unclaimed remains buried in Milanese cemetery and housed at the LABANOF [32 (link)]. In addition to being contemporary (with individuals who died in the 20th century, including 80% after 1980), the collection has the advantage of being documented, meaning that the individuals are associated to a documentation that includes sex, age-at-death, date of birth, date of death, cause of death, and pathological conditions related to it. The individuals of the CAL Milano Cemetery Skeletal Collection were primarily selected based on their ages-at-death, in order to correspond to the same age range as that of the migrants, that is, between 20 and 35 years. From this criterion, a total of 28 individuals were found in the collection. However, this young age-at-death requirement created a selective mortality bias in the sample which was considered. The non-migrant sample was therefore clearly contextualized and the limitations in inferences were clearly set in order to deal with this selectivity bias. The second selection criterion was the good preservation of the remains, specifically of the cranium and mandible; only skeletons for which the three stress markers selected could be potentially observable (i.e., preservation of the orbits and cranial vault, presence of at least half of the dentition) were selected, which resulted in the removal of three cases from the sample. These two criteria of selection (age-at-death and preservation) thus resulted in a sample constituted of 19 males and 6 females, all of Italian descent. Biological profile was only estimated for the migrant sample, since this data was already known for the cemetery sample.
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