Introduction: The Canaries and Aboriginal Origins

Population origins and the development of insular cultures in the Canary Islands present archaeology with complex questions. Various proposals regarding the initial human occupation of this region suggest a broad timeframe spanning from c. 1000 bc to ad 300. Palaeogenetic evidence, discussed below, hints at the influence of at least two major migratory events led by North African populations. Analysis of ancient DNA (aDNA) from Canary aboriginals reveals a genetic mosaic with contributions from North African, sub-Saharan, and southern European haplogroups. However, despite archaeological advances, fundamental questions common to theory of island archaeologies, such as the ‘who, when, where from, and why’ (Napolitano et al., Reference Napolitano, DiNapoli, Stone, Napolitano, Stone and DiNapoli2021: 15) continue to challenge scholars in the context of the Canary Islands. Obstacles arise from the highly disturbed state of the Canarian aboriginal material record and the subtle fragmentation in collaborative approaches.

European colonization began in the fifteenth century ad, followed by 200 years of looting motivated by antiquarianism causing the loss of innumerable artefacts and mortuary remains (Álvarez Sosa & Morfini, Reference Álvarez Sosa and Morfini2014; Ortiz-García, Reference Ortiz-García2016). Since the 1950s, overdevelopment to satisfy tourist demands and the consequent destruction of archaeological sites (Mazzola de Los Ríos, Reference Mazzola de Los Ríos2016) have left many unfillable gaps. Furthermore, the politicization of archaeology to legitimize nationalist movements, such as those led by the Francoist regime or the 1980s Canarian terrorist group known as the Movement for the Independence and Autonomy of the Canarian Archipelago (MPAIAC), have tainted academic and public discourse (Farrujia de la Rosa & del Arco-Aguilar, Reference Farrujia de la Rosa, del Arco-Aguilar, de Barradas, Sánchez and Morales-Padrón2004).

Currently, two theoretical perspectives, labelled here the Mediterraneanist versus North Africanist stance, dominate discussions on the peopling of the Canary Islands. Both acknowledge the importance of the Maghreb region as an ancestral place of origin for tribes of the Canary Islands, but the Mediterraneanists differ from the North Africanists in hypotheses related to the cultural and chronological origin of the first settlers (Figure 1).

Figure 1. Location of the Canary Islands and surrounding territories within the temporal context of c. 270 bc. Major Punic—later Roman—urban centres are marked with their Latin names. Given our lack of knowledge on the exact routes that ancient settlers used to reach the archipelago, the paths drawn are not intended to represent literal routes proposed by other authors; instead, they are provided as a guide to illustrate differences in peopling origins within the Maghreb region.

Mediterraneanists posit that the Canary archipelago was settled during the Late Bronze Age to Iron Age transition by palaeo-Berber populations of Phoenico-Punic affinity (Atoche-Peña, Reference Atoche-Peña, Waldren and Ensenyat2002). Following a stepping-stone model (del-Arco-Aguilar, 2021), Phoenician seafarers are thought to have moved westward from the easternmost islands, establishing economic outposts along the north-western African coasts for resource exploitation (Bueno-Ramírez et al., Reference Bueno-Ramírez, Balbín-Behrmann, del Arco-Aguilar and González-Antón1995; González Antón et al., Reference González Antón, del Arco Aguilar, Balbín Behrmann and Bueno Ramírez1998; González Antón & del Arco Aguilar, Reference González Antón and del Arco Aguilar2009). Romanized North African peoples subsequently maintained these commercial outposts (Mederos Martín & Escribano Cobo, Reference Mederos Martín and Escribano Cobo2002), possibly in contact with earlier Phoenico-Punic (and/or) palaeo-Berber islanders. In Lanzarote, Roman material culture has been found alongside native artefacts at El Bebedero, Caldereta de Tinache, and Buenavista (Atoche-Peña, Reference Atoche-Peña2011) (Figure 2). Recent discoveries, including the Lobos royal red factory (del-Arco-Aguilar et al., Reference del-Arco-Aguilar, del-Arco-Aguilar, Benito-Mateo and Rosario-Adrián2016), confirm the Roman presence in the Canary Islands (Blázquez, Reference Blázquez1977). Pliny the Elder's Historia Naturalis additionally describes the profiteering character of Roman incursions (Santana Santana, Reference Santana Santana2002).

Figure 2. The Canary Islands with sites mentioned in the text noted.

North Africanists propose that the peopling of the Canary Islands was led by autochthonous Amazigh groups, the ancestors of pastoralist Berbers from present-day Morocco, Tunisia, and Algeria (Navarro Mederos, Reference Navarro Mederos1997; Tejera Gaspar et al., Reference Tejera Gaspar, Chávez Álvarez and Montesdeoca2006; Fregel et al., Reference Fregel, Ordóñez, Santana-Cabrera, Cabrera, Velasco-Vazquez and Alberto2019). This approach encompasses various peopling models with differing timelines. Some scholars attribute the relocation of unskilled seafaring Berber tribes to the Romans (Tejera Gaspar et al., Reference Tejera Gaspar, Chávez Álvarez and Montesdeoca2006; Jiménez González, Reference Jiménez González2013). Others interpret rock art and linguistics as evidence of initial settlement around 500 bc, first by an ‘Archaic Amazigh’ group followed by a ‘Romanized Amazigh’ migration (Farrujia de la Rosa et al., Reference Farrujia de la Rosa, Pichler and Rodrigue2009). Another perspective, using human skeletal remains from funerary contexts, suggests a multiple-wave settlement process starting around ad 250, with a second migration around ad 600 (Alberto-Barroso et al., Reference Alberto-Barroso, Velasco-Vázquez, Delgado-Darias, Moreno-Benítez and Castillo2020, Reference Alberto-Barroso, Velasco-Vázquez, Delgado-Darias and Moreno-Benítez2021). Currently, no human remains dating to before c. ad 250 have been found (Figure 2).

Issues regarding radiocarbon dates ensure that the North Africanists and Mediterraneanists continue to disagree (Velasco-Vázquez et al., Reference Velasco-Vázquez, Alberto-Barroso, Delgado-Darias, Moreno-Benítez, Lécuyer and Richardin2020; Atoche-Peña & del-Arco-Aguilar, Reference Atoche-Peña and del-Arco-Aguilar2023). Additionally, there has been a tendency to underutilize indirect evidence from palaeoecology and palaeostratigraphic studies that suggest a human presence in the Canaries during the mid- to late Holocene (Meco et al., Reference Meco, Lomoschitz, Rodríguez, Ramos, Betancort and Coca2018; Ravazzi et al., Reference Ravazzi, Mariani, Criado, Garozzo, Naranjo-Cigala and Perez-Torrado2021). A lack of archaeological findings suggesting inter-insular communication obscures knowledge on the ancient seafaring abilities of Canary tribes. Finally, the casual use of words like ‘exploration’, ‘utilization’, and ‘settlement’ or ‘colonization’ confuses discourses of settlement models in Canarian archaeology. These issues have fuelled debate whether substrate populations arrived independently or were brought in.

Island Settlement and Archaeological Theory

The literature on island archaeology regarding human insular settlement is vast, drawing on many influences (Sahlins, Reference Sahlins1955; Broodbank, Reference Broodbank2000; Erlandson & Fitzpatrick, Reference Erlandson and Fitzpatrick2006; Rainbird, Reference Rainbird2007; Dawson, Reference Dawson2014). Biogeography is seen as the foundation for theory on island archaeology (Evans, Reference Evans and Renfrew1973) and it emphasized the ecological constraints and origins of biological diversity within insular environments (MacArthur & Wilson, Reference MacArthur and Wilson1967). Human biogeography put special attention to size, distribution, population structure, and interactivity among island communities (Terrell, Reference Terrell1976). In Mediterranean landscapes, Cherry (Reference Cherry1981) defied biological determinism by arguing that human island occupation was a nuanced sociocultural process. Then, the term ‘islandscapes’ was introduced to underline the human element in island lifestyles and landscape awareness (Broodbank, Reference Broodbank2000). The dichotomy between isolation and interaction has been largely discussed (Terrell et al., Reference Terrell, Kelly and Rainbird2001; Fitzpatrick & Anderson, Reference Fitzpatrick and Anderson2008), stressing that island communities should be studied with other geographic systems (Terrell, Reference Terrell2020; Dawson et al., Reference Dawson, Picornell-Gelabert, Calvo-Trias, Servera-Vives and Valenzuela-Oliver2023).

Deciphering the peopling of islands has relied on multiple settlement models. Initially, archaeological theories of insular occupation were grounded in comparative ethnology, with diffusionism prominent in the early twentieth century. As the discipline transitioned towards multidisciplinarity, holistic models began to integrate anthropology's four-field approach, which combines linguistics, archaeology, physical, and cultural anthropology (Patrick, Reference Patrick2010). Multiple factors may have influenced human migration. Environmental approaches, considering past landscape changes, elucidate how the Pleistocene sea level drop may have driven the peopling of Island Southeast Asia for example (O'Connor & Hiscock, Reference O'Connor, Hiscock, Cochane and Hunt2018). Ideological processes may also have prompted human migration to new regions (Napolitano et al., Reference Napolitano, DiNapoli, Stone, Napolitano, Stone and DiNapoli2021). Observed among Polynesian island tribes, the practice of primogeniture restricted non-firstborn offspring from inheriting local land, thus potentially facilitating the ancient settlement of new landscapes (Bellwood, Reference Bellwood, Fox and Sather1996). Furthermore, the study of seafaring technology has been key in understanding settlement narratives.

Human Settlement Models for the Canary Islands

In using the categories by Guerrero Ayuso (Reference Guerrero Ayuso2001) to discuss the phases of human settlement in the Canary Islands, I emphasize the differences between discovery or exploration, utilization, and settlement or colonization. Exploratory activities encompass purposeful, planned missions, followed by utilization, defined as ‘many, tentative, impermanent, short-distance reciprocal movements’ (Cherry, Reference Cherry1981: 60), preceding stable settlements. Archaeologists recognize the complexity of finding material culture and human remains linked to early exploration (Dawson, Reference Dawson2004). In the Canaries, coastal landscape alterations due to tourism-related development projects (Mazzola de Los Ríos, Reference Mazzola de Los Ríos2016) have hindered the investigation of sites where discovery activities may have occurred. Mediterraneanists argue that evidence of ancient exploration resides in ancient rock art. The petroglyphs of Barranco de Tinojay, Fuerteventura (Amezcua, Reference Amezcua, Hormiga, Arbelo and Mesa1995), and in El Cercado, La Palma (Mederos Martín & Escribano Cobo, Reference Mederos Martín and Escribano Cobo1997) (Figure 2), suggest depictions of Phoenician ships (González Antón et al., Reference González Antón, del Arco Aguilar, Balbín Behrmann and Bueno Ramírez1998). Ancient texts also provide evidence of pre-Hellenic seafaring expeditions to the Canaries. Accounts such as the fourth-century bc Periplus of Pseudo-Scylax (Shipley, Reference Shipley2020), Pharaoh Necho II's expedition to Africa around 600 bc, the voyages of the Greek geographer Hecataeus of Miletus (c. 550–476 bc), and the fifth-century bc Carthaginian Hanno the Navigator together suggest an exploratory phase during the Iron Age preceding settlement in the Canary Islands (Santana Santana, Reference Santana Santana2002).

The possibility of exploratory arrivals evolving into utilization during the Bronze Age aligns with the long history of Homo sapiens’ oceanic navigation (Westaway, Reference Westaway2019). Considering the known Phoenician presence on African Atlantic coasts (Stieglitz, Reference Stieglitz1984), a Phoenico-Punic arrival to the Canaries during the Late Bronze Age (González Antón & del Arco Aguilar, Reference González Antón and del Arco Aguilar2007) does not oppose additional small-scale arrivals of north-western African herders. These groups may have ventured onto the seas for various reasons, such as escaping demographic or environmental pressures (Onrubia Pintado, Reference Onrubia Pintado2001). During a stage of frequent visitation, the first settlers would have begun the process of landscape learning via cultural adaptations (Dawson, Reference Dawson2014) leading towards establishment of permanent communities and potential colonization of natural resources. Insular settlement stages may, however, not be linear, resulting in multiple settlement attempts by different people (Guerrero Ayuso, Reference Guerrero Ayuso2001). Consequently, abandonment becomes a factor (Dawson, Reference Dawson2010), introducing complexity into the study of island peopling. According to Castilian chronicles written between the fifteenth and seventeen centuries ad, an ancient Canarian provenance myth attributes their origin to an abandonment by seafarers (Jiménez Gómez, Reference Jiménez Gómez2003). Mediterraneanists hypothesize abandonment as part of the fall of the Carthaginians post Punic Wars, leaving a reduced population in the islands or complete desertion until the arrival of the Romans. Upon the fall of the Roman Empire, another major abandonment may have occurred (Atoche-Peña, Reference Atoche-Peña2013).

Distinguishing between visitation and colonization is necessary to understanding the process involved in landscape exploitation. However, the often-limited archaeological material from these settlement stages presents a challenge (Broodbank, Reference Broodbank and Halstead1999; Guerrero Ayuso, Reference Guerrero Ayuso2001). In the Canary Islands, osteological evidence from exploration and/or utilization periods is scarce—or non-existent—compared to the extensive skeletal record found in permanent settlements and/or colonization contexts. Site preservation is also a problem when attempting to identify peopling stages based on architectural typologies. Aboriginal architecture in the Canaries is characterized by freestanding stone walls and the construction of artificial caves, while natural cavities were often used for burials (Rodríguez-Martín & Martín-Oval, Reference Rodríguez-Martín and Martín-Oval2009; Alberto-Barroso et al., Reference Alberto-Barroso, Delgado-Darias, Velasco-Vázquez and Santana-Cabrera2016). The repurposing of early settlements by historical inhabitants and local herders further complicates stratigraphic analyses. Yet, indirect clues may be found through palaeoecological studies. For instance, the presence of Mus musculus domesticus (house mouse) has been linked to a Roman presence in El Bebedero, Lanzarote (Criado & Atoche, Reference Criado and Atoche2003). The single specimen KIA-36470, calibrated using intcal04.14C and with 2σ interval, yielded an age of ad 128–313 (1815 ± 25 bp) (Alcover et al., Reference Alcover, Rando, García-Talavera, Hutterer, Michaux and Trias2009). Furthermore, at La Monja site in Fuerteventura (Figure 2), researchers found an ovicaprid bone and red ochre within an alluvial deposit intercalated between two marine beachrocks from two Holocene highstands. The lower deposit, dating to about 2830 bc (Meco et al., Reference Meco, Muhs, Fontugne, Ramos, Lomoschitz and Patterson2011), represents the Middle Holocene period, while the younger deposit, dated at about ad 490, represents the Late Holocene period (Meco et al., Reference Meco, Muhs, Fontugne, Ramos, Lomoschitz and Patterson2011; Reference Meco, Lomoschitz, Rodríguez, Ramos, Betancort and Coca2018). Despite the long chronological gap between these dated deposits, the stratigraphic nature has been interpreted as an indication of anthropogenic landscape changes causing erosion during a period of use (Onrubia Pintado et al., Reference Onrubia Pintado, Meco and Fontugne1997).

The transformation of forests into open landscapes is often linked to land optimization for grazing and agriculture, characteristic of permanent and intensive anthropogenic activities (Guerrero Ayuso, Reference Guerrero Ayuso2001). Evidence of such modifications in the Canary Islands has been investigated via palynological records from sediment cores in the La Laguna Lake basin, Tenerife. This evidence suggests a decline in Quercus (oak) and Carpinus (birch) pollen taxa between 2735 and 35 bc, coinciding with the emergence of shrubs, grasses, and the laurel forest (de Nascimento et al., Reference de Nascimento, Willis, Fernández-Palacios, Criado and Whittaker2009). Fossil charcoal remains hint at the occurrence of intense fires in La Gomera over the last 3600 years, with pollen records documenting a shift in vegetation from the endemic laurel forest to a drier woody heath (Nogué et al., Reference Nogué, de Nascimento, Fernández-Palacios, Whittaker and Willis2013). In Gran Canaria, studies on fossil charcoal reveal an increase in fire episodes around 435–335 bc (de Nascimento et al., Reference de Nascimento, Nogué, Criado, Ravazzi, Whittaker and Willis2015; Reference de Nascimento, Nogué, Naranjo-Cigala, Criado, McGlone and Fernández-Palacios2020).While volcanic activity may have played a role in these deposits, Ravazzi et al. (Reference Ravazzi, Mariani, Criado, Garozzo, Naranjo-Cigala and Perez-Torrado2021) argue that the lack of forest recovery and the abundance of coprophilous fungal spores in sediment cores suggest anthropogenic activity as the likely cause.

An additional characteristic of intensive human settlements is demographic stress (Guerrero Ayuso, Reference Guerrero Ayuso2001), also described by ethnohistory in the Canary Islands (Morales Padrón, Reference Morales Padrón1978). Archaeological evidence from multiple silos throughout Gran Canaria (Ascanio-Padrón et al., Reference Ascanio-Padrón, Mendoza-Medina, Moreno-Benítez, Suárez-Medina and Morales-Padrón2004; Henríquez-Valido et al., Reference Henríquez-Valido, Morales-Mateos, Vidal-Matutano, Santana-Cabrera and Rodríguez Rodíguez2019) confirms the presence of a large native population dependent on surplus. Wheat, barley, and legumes were mostly grown on the larger islands of Gran Canaria and Tenerife, where intensive sheep/goat herding was also practised (del-Arco-Aguilar et al., Reference del-Arco-Aguilar, de-Arco-Aguilar, Atiénzar Armas and Hopf1990; Velasco-Vázquez, Reference Velasco-Vázquez1999; Morales Mateos, Reference Morales Mateos2006). Islanders also hunted and foraged wild resources to supplement their diet (Arnay-de-la-Rosa et al., Reference Arnay-de-la-Rosa, González-Reimers, Yanes, Velasco-Vázquez, Romanek and Noakes2010; Reinhard et al., Reference Reinhard, Martín-Oval, del-Arco-Aguilar, Rodríguez-Maffiotte-Martín and del-Arco-Aguilar2021). Hunter-gatherer economies could have been more significant on islands where agriculture did not reach productive levels, such as in Fuerteventura (González-Reimers et al., Reference González-Reimers, Velasco-Vázquez, Arnay de la Rosa, Santolaria-Fernández and Galindo-Martín2001) or La Palma (Pérez González, Reference Pérez González2007). To cope with carrying capacity, social formations may develop strategies such as crop diversification, storage, subsistence heterogeneity, trading, mobility, and other cultural adaptations (Guerrero Ayuso, Reference Guerrero Ayuso2001). These activities were evident throughout the Canaries since at least c. ad 665 (Morales et al., Reference Morales, Rodríguez, Alberto, Machado, Criado and Rando2013).

Canarian Human Palaeogenomics and Settlement Models

Recent investigations by Serrano and colleagues (Reference Serrano, Ordóñez, Santana, Sánchez-Cañadillas, Arnay and Rodríguez-Rodríguez2023) have offered novel wide-genome data and radiocarbon dates showing the potential contributions of three main population sources to basal Canary islanders: ancient Maghrebi, early Neolithic European, and Eurasian Steppe groups. This study reaffirms the high haplotypic diversity among first settlers, indicating genetic variation resulting from at least two major waves of settlement (Rodríguez-Varela et al., Reference Rodríguez-Varela, Günther, Krzewińska, Storå, Gillingwater and MacCallum2017; Fregel et al., Reference Fregel, Ordóñez, Santana-Cabrera, Cabrera, Velasco-Vazquez and Alberto2019; Serrano et al., Reference Serrano, Ordóñez, Santana, Sánchez-Cañadillas, Arnay and Rodríguez-Rodríguez2023). Ancient mitochondrial DNA (mtDNA) analyses support the idea that matrilineal kinship systems were in place, at least within the population of Punta Azul, in El Hierro Island (Ordóñez et al., Reference Ordóñez, Arnay and Fregel2021). Also, palaeogenetics provides valuable insights into inter- and intra-insular migration trends. For example, it reveals the presence of the mtDNA haplogroup H in Tenerife (47.2 per cent) and La Palma (56.7 per cent) suggesting reciprocal contact between the western Canary Islands (Fregel et al., Reference Fregel, Pestano, Arnay, Cabrera, Larruga and Gonzalez2009), but not with the eastern islands (Serrano et al., Reference Serrano, Ordóñez, Santana, Sánchez-Cañadillas, Arnay and Rodríguez-Rodríguez2023). Hence, it has been proposed that there was some inter-island connectivity during the second to ninth centuries ad, followed by a period of isolation from the ninth to the fourteenth century. Yet, the easternmost region faces a challenge, as the primary palaeogenetic dataset comes from Gran Canaria and Tenerife, with Lanzarote and Fuerteventura represented by only four individuals dated between the seventh and ninth centuries ad. The absence of human remains for the eastern islands is problematic, considering the stepping-stone model assumes this region would have been occupied first (Atoche-Peña & del-Arco-Aguilar, Reference Atoche-Peña and del-Arco-Aguilar2023), and should therefore provide the oldest human genotypes. Interestingly, genomic data from extant barley seeds indicates that an older grain strain was grown in Lanzarote and exchanged between eastern and western islands (Hagenblad & Morales, Reference Hagenblad and Morales2020), thus supporting the stepping-stone model.

The diversity detected in aDNA findings has already been observed in the archaeological and ethnohistoric record. This is evident in the presence of different ceramic types, votive iconography, burial practices, political systems, and language (Onrubia Pintado, Reference Onrubia Pintado1992; Navarro Mederos, Reference Navarro Mederos1997; Alberto-Barroso & Velasco-Vázquez, Reference Alberto-Barroso and Velasco-Vázquez2010; del Pino Curbelo et al., Reference del Pino Curbelo, Rodríguez Rodríguez, Buxeda i Garrigós, Mangas Viñuela, Day and González Quintero2016). Attributing the origins of the initial settlers to North African descent is merely stating a geographical reality. The novelty lies in recognizing the ethnic and cultural diversity that existed among the ancient Canary aboriginals, evident in both their paternal and maternal ancestral lines (Supplementary Materials: Tables S1 and S2). The presence of Y-chromosome single nucleotide polymorphisms such as T-M184 or E-M33 have acknowledged the membership of first islanders to broader ancestral groups like T or E haplogroups from different geographic origins (Table S2). The human settlement of the Canary archipelago was a complex process, marked by intricate migratory movements akin to those involved in the peopling of the vast region of North Africa over millennia (Simões et al., Reference Simões, Günther, Martínez-Sánchez, Vera-Rodríguez, Iriarte and Rodríguez-Varela2023).

Overreliance on a single method to determine the initial human settlement of the Canaries and neglecting island settlement theory and traditional archaeological methods may yield oversimplified population stories. As mentioned earlier, distinct stages of insular colonization leave behind specific archaeological evidence. The majority of radiocarbon dates associated to palaeogenetic findings belong to ad fifth century and beyond. Hence, I suggest that skeletal material used in aDNA investigations may belong to adapted populations, indicating a stage of permanent settlement rather than an initial colonization or exploration period in the Canary Islands. Another issue concerns the lack of emphasis on radiocarbon methodology. The most influential and recent publications in Canarian palaeogenetics (Fregel et al., Reference Fregel, Ordóñez, Santana-Cabrera, Cabrera, Velasco-Vazquez and Alberto2019; Serrano et al., Reference Serrano, Ordóñez, Santana, Sánchez-Cañadillas, Arnay and Rodríguez-Rodríguez2023) do not provide details on the laboratory methods used to obtain chronological data from human bone, and they often lack proper calibration of dates. This oversight is particularly concerning for islander populations with direct access to marine resources that would possibly increase the reservoir effect from enriched marine carbon consumed via food. Thus, if archaeologists are to solely rely on the accuracy and precision of the radiocarbon dating method to support specific population histories, we should then consider the intricacies behind the methods and the interpretation of quantitative results.

Radiocarbon Dating and Canarian Archaeology

Chronologies, both radiocarbon and dated aDNA data, are contested in Canarian archaeology (for a comprehensive list of radiocarbon measurements published in the Canaries, see the bibliography cited in this section and sources therein). Some researchers dispute the validity of key dates obtained from long-lived materials such as wood or charcoal (Pardo-Gordó et al., Reference Pardo-Gordó, González Marrero, Vidal Matutano and Rodríguez-Rodríguez2022). Insufficient stratigraphic context or doubtful laboratory practices contribute to the scepticism (Velasco-Vázquez et al., Reference Velasco-Vázquez, Alberto-Barroso, Delgado-Darias, Moreno-Benítez, Lécuyer and Richardin2020) surrounding the utilization of chronologies proposing a Late Bronze and Early Iron Age human settlement (Atoche-Peña & del-Arco-Aguilar, Reference Atoche-Peña and del-Arco-Aguilar2023). Also, radiocarbon chronologies indicating that the colonization of Gran Canaria took place in c. ad 300 (Alberto-Barroso et al., Reference Alberto-Barroso, Delgado-Darias, Moreno-Benítez and Velasco-Vázquez2019) cast doubts on the basis of collagen processing methods used to prepare bone samples (Pardo-Gordó et al., Reference Pardo-Gordó, González Marrero, Vidal Matutano and Rodríguez-Rodríguez2022). Other issues affecting human collagen radiocarbon dating include a lack of consideration for the calibration of chronometric measurements such as the marine carbon reservoir effect (MCRE) and the establishment of a local regional (ΔR) offset (Pardo-Gordó et al., Reference Pardo-Gordó, González Marrero, Vidal Matutano and Rodríguez-Rodríguez2022). Furthermore, the methodological challenges to define and discuss all components of Bayesian modelling in constructing ¹⁴C sequences are a pervasive issue in archaeology (Bayliss, Reference Bayliss2015), and so in the Canaries.

In the Canaries, the current body of radiocarbon-dated skeletons is marked by a conspicuous absence of information regarding laboratory pretreatment protocols. This omission hampers our ability to assess the reliability of results. Notably, even in the most comprehensive aDNA dataset published to date, there remains a gap in the discussion of the methodology employed to obtain ¹⁴C dates from human skeletons, particularly those involving non-collagen data (Serrano et al., Reference Serrano, Ordóñez, Santana, Sánchez-Cañadillas, Arnay and Rodríguez-Rodríguez2023). In the field of Canarian archaeology, discrepancies remain on the appropriateness of the sample materials despite established global agreements (Waters et al., Reference Waters, Stafford and Carlson2020) and the absence of detailed sample cleaning protocols to isolate collagen (Devièse et al., Reference Devièse, Stafford, Waters, Wathen, Comeskey and Becerra-Valdivia2018). Furthermore, caution is warranted when interpreting dates derived from sediments, ash, and those generated at the Gakushuin laboratory (Blakeslee, Reference Blakeslee1994; Waters et al., Reference Waters, Stafford and Carlson2020).

Of considerable concern for the chronometric hygiene of published datasets from ancient Canarian human bone, the MCRE is not considered here when applying calibration curves to radiocarbon dates (Pardo-Gordó et al., Reference Pardo-Gordó, González Marrero, Vidal Matutano and Rodríguez-Rodríguez2022). The lag in carbon cycling between the atmosphere and the surface ocean, compounded by exchanges between surface and deeper ocean radiocarbon levels, further complicates the mixing process. Indeed, regions characterized by notable ocean upwelling events, as observed in coastal southern Iberia (Monge Soares, Reference Monge Soares1993), exhibit variations in radiocarbon concentrations due to seawater mixing and upwelling phenomena that ought to be considered (Bronk Ramsey, Reference Bronk Ramsey2008). The Canary archipelago is possibly affected by different upwelling events, such as the north-west Africa coastal upwelling system (Soares & Dias, Reference Soares and Dias2007). In a study by Matos Martins and colleagues (Reference Matos Martins, Mederos Martín, Cesário Portela and Monge Soares2012), using archaeological marine shells, burnt wood, and/or bones from Fuerteventura and Tenerife, researchers calculated differential offsets in Tenerife showing lower ΔR values (weighted mean 0 ± 35 ¹⁴C yr) compared to Fuerteventura (+185 ± 30 ¹⁴C yr). A high ΔR has been correlated with strong upwelling versus the low or negative ΔR that represents less seawater rising (Matos Martins et al., Reference Matos Martins, Mederos Martín, Cesário Portela and Monge Soares2012). Although context uncertainty exists in some of the samples utilized by Matos Martins and colleagues (Reference Matos Martins, Mederos Martín, Cesário Portela and Monge Soares2012), their work establishes a precedent for a careful consideration of oceanic phenomena, particularly the MCRE impacting ¹⁴C measurements in ancient human bone of the Canary Islands.