Paleodietary analysis on the prehistoric population of El Hierro (Canary Islands)

In order to deepen our knowledge of the dietary habits of the prehispanic inhabitants of El Hierro, we have determined bone strontium (Sr), manganese (Mn), magnesium (Mg), copper (Cu), zinc (Zn), and calcium (Ca) in 52 human tibiae (23 belonging to males and 20 to females individuals) buried in a single burial cave; in 21 modern individuals who served as controls; and in 11 bones of herbivores found at archeological sites of the Canary Islands. Results suggest that females consumed a more vegetarian diet, although site-corrected Sr/Ca ratio of both males and females speaks for a mixed-diet consumption.     

Paleodietary analysis on the prehistoric population of El Hierro (Canary Islands)

In order to deepen our knowledge of the dietary habits of the prehispanic inhabitants of El Hierro, we have determined bone strontium (Sr), manganese (Mn), magnesium (Mg), copper (Cu), zinc (Zn), and calcium (Ca) in 52 human tibiae (23 belonging to male and 20 to female individuals) buried in a single burial cave; in 21 modern individuals who served as controls; and in 11 bones of herbivores found at archeological sites of the Canary Islands. Results suggest that females consumed a more vegetarian diet, although site-corrected Sr/Ca ratio of both males and females speaks for a mixed-diet consumption.     

Bone cadmium and lead in the ancient population from El Hierro, Canary Islands

This study was performed to determine the levels of lead (Pb) and cadmium (Cd) in 63 bone samples of the prehispanic population of the island El Hierro, comparing them with the values obtained on 98 prehispanic samples from Tenerife, Fuerteventura, Gran Canaria, and La Palma, all of them in the Canary Islands, and with eight modern samples who served as controls. Prehispanic individuals from El Hierro showed the lowest bone Pb values of all the archipelago (0.72±1.01 mg/kg), significantly different (F=6.9, p<0.001) from the values obtained for the population of other islands such as Tenerife (4.87±5.36 mg/kg) or Fuerteventura (4.45±7.85 mg/kg) and also from those of the modern population (30.53±14.62 mg/kg). On the other hand, bone Cd, although slightly lower in the ancient population groups, was not significantly different when compared with the modern one. In addition, no differences were observed in bone Cd among the ancient population of the different islands. Bone lead—but not cadmium—kept an inverse significant relationship with the distance of the burial site both to south Spain (r=−0.31) and Atlantic Morocco (r=−0.28, p<0.001 in both cases).     

Human enzyme polymorphism on the Canary Islands. I. Gran Canaria Island population

Genetic polymorphism of seven red cell enzymes was examined in two Canary Island populations and in an Iberian peninsula sample. The more isolated insular population shows a considerable gene frequency heterogeneity when compared with the peninsular sample but both are within the range of European populations. The presence of certain rare alleles normally associated with blacks suggests an African component in the Canarian populations.     

Harris lines in the prehispanic population of Gran Canaria (Canary Islands)

Harris lines were assessed in 194 right tibiae of prehispanic inhabitants of Gran Canaria, belonging to 52 adult females and 123 adult males. No Harris lines were detected in 45 (23%) of the adult individuals (13 females (25%) and 26 males (21%), these differences being not statistically significant. Female tibiae showed a slightly lower mean number of Harris lines at the distal end than male ones (1,692±1.681 in females vs 1.91±1.825 in males). Ages at which Harris lines were formed showed two peaks, a major one at the age of 1 year, and another between 15 and 16 years in males and between 11–12 and 14–15 years in females. Harris lines were more frequently observed at the distal than at the proximal end of the bone. The relative low number of lines detected in our population when compared with the high prevalence of osteoporosis among the adult population of this island is striking.     

Auricular exostoses in the prehistoric population of Gran Canaria

Auditory exostoses are bone anomalies located in the external auditory canal. The bulk of clinical observations and some experimental data support the idea that their development depends on prolonged exposure to cold water. This study was performed in order to analyze the prevalence of auditory exostoses among the prehispanic population of Gran Canaria, comparing it between men and women and between individuals buried in coastal regions and central highlands. We analyzed 323 crania, 41 of which showed auditory exostoses. Marked differences in prevalence were observed between the individuals buried in the central highlands (0.88%) and those buried in coastal regions (40.21%). Among the latter, the prevalence was similar in men (41.67%) and in women (38.89%). These data support the hypothesis that individuals buried in coastal regions performed economic activities related to exploitation of marine resources, whereas those living in the central highlands did not; however, diachronic variation cannot be excluded.     

The helminth community of the skink Chalcides sexlineatus from Gran Canaria (Canary Islands)

A survey of the gastrointestinal helminth communities of a population of Chalcides sexlineatus Steindachner, a small skink endemic to Gran Canaria island (Canary Archipelago, Spain), was conducted to determine the prevalence, abundance and species diversity of intestinal parasites in these reptiles. Only three parasite species were found, one cestode, Oochoristica agamae Baylis, 1919 and two nematodes, Parapharyngodon micipsae (Seurat, 1917) and Pharyngodonidae gen. sp. Helminth infracommunities of C. sexlineatus showed low values of abundance and species richness and diversity, being more similar to the helminth community of Tarentola boettgeri boettgeri (Steindachner) rather than those of Gallotia stehlini (Schenkel), both syntopic with the sampled host.     

Pollen and sensorial characterization of different honeys from El Hierro (Canary Islands)

The pollen content of 31 honey samples from 19 different apiaries of El Hierro (Canary Islands) were subject to qualitative and quantitative melissopalynological analysis. The quantitative analysis demonstrated that 13% of the honey belonged to Maurizio Class I (<2?000?grains), 68% to Class II (2?000–10?000?grains) and 19% to Class III (10?000–50?000?grains). The pollen density ranges from 1?042?grains/g of honey to 24?478?grains/g with an average of 7?471?grains/g. According to the qualitative analysis, six honeys were typified as unifloral and 25 as multifloral. The unifloral honey samples were broken down as follows: two of heather (Erica arborea L.), two of Chamaecytisus proliferus (L. f.) Link‐type (“tagasaste”), one of Fabaceae (Genisteae sp.) and one of Lamiaceae Origanum vulgare L. ssp. virens (Hoffmanns. &; Link) Ietsw.‐type (thyme: Micromeria hyssopifolia Webb &; Berthel.). Honeydew elements were practically absent. Sixty‐nine pollen types were identified belonging to 42 families. The number of pollen types range between 18 and 39 (mean of 27.42). Foeniculum vulgare Mill.‐type pollen is present in all the samples. Galactites tomentosa Moench‐type, Echium plantagineum L., Echium L. sp., Bituminaria bituminosa (L.) C. H. Stirt., Chamaecytisus proliferus ‐type and Origanum vulgare ssp. virens ‐type pollen were found in 96.8% of the samples. The sensorial analysis indicated that honey types are generally of good quality, because 62% were evaluated as very high (16%), high (23%), and good (23%).     

Phylogeography of the endangered darkling beetle species of Pimelia endemic to Gran Canaria (Canary Islands)

Phylogenetic and geographical nested clade analysis (NCA) methods were applied to mitochondrial DNA sequences of Pimelia darkling beetles (Coleoptera, Tenebrionidae) endemic to Gran Canaria, an island in the Canary archipelago. The three species P. granulicollis, P. estevezi and P. sparsa occur on the island, the latter with three recognized subspecies. Another species, P. fernandezlopezi (endemic to the island of La Gomera) is a close relative of P. granulicollis based on partial Cytochrome Oxidase I mtDNA sequences obtained in a previous study. Some of these beetles are endangered, so phylogeographical structure within species and populations can help to define conservation priorities. A total of about 700 bp of Cytochrome Oxidase II were examined in 18 populations and up to 75 individuals excluding outgroups. Among them, 22 haplotypes were exclusive to P. granulicollis and P. estevezi and 31 were from P. sparsa. Phylogenetic analysis points to the paraphyly of Gran Canarian Pimelia, as the La Gomera P. fernandezlopezi haplotypes are included in them, and reciprocal monophyly of two species groups: one constituted by P. granulicollis, P. estevezi and P. fernandezlopezi (subgenus Aphanaspis), and the other by P. sparsa'sensu lato'. The two species groups show a remarkably high mtDNA divergence. Within P. sparsa, different analyses all reveal a common result, i.e. conflict between current subspecific taxonomic designations and evolutionary units, while P. estevezi and P. fernandezlopezi are very close to P. granulicollis measured at the mtDNA level. Geographical NCA identifies several cases of nonrandom associations between haplotypes and geography that may be caused by allopatric fragmentation of populations with some cases of restriction of gene flow or range expansion. Analyses of molecular variance and geographical NCA allow definition of evolutionary units for conservation purposes in both species-groups and suggest scenarios in which vicariance caused by geological history of the island may have shaped the pattern of the mitochondrial genetic diversity of these beetles.     

Transient Changes in Bacterioplankton Communities Induced by the Submarine Volcanic Eruption of El Hierro (Canary Islands)

The submarine volcanic eruption occurring near El Hierro (Canary Islands) in October 2011 provided a unique opportunity to determine the effects of such events on the microbial populations of the surrounding waters. The birth of a new underwater volcano produced a large plume of vent material detectable from space that led to abrupt changes in the physical-chemical properties of the water column. We combined flow cytometry and 454-pyrosequencing of 16S rRNA gene amplicons (V1–V3 regions for Bacteria and V3–V5 for Archaea) to monitor the area around the volcano through the eruptive and post-eruptive phases (November 2011 to April 2012). Flow cytometric analyses revealed higher abundance and relative activity (expressed as a percentage of high-nucleic acid content cells) of heterotrophic prokaryotes during the eruptive process as compared to post-eruptive stages. Changes observed in populations detectable by flow cytometry were more evident at depths closer to the volcano (~70–200 m), coinciding also with oxygen depletion. Alpha-diversity analyses revealed that species richness (Chao1 index) decreased during the eruptive phase; however, no dramatic changes in community composition were observed. The most abundant taxa during the eruptive phase were similar to those in the post-eruptive stages and to those typically prevalent in oceanic bacterioplankton communities (i.e. the alphaproteobacterial SAR11 group, the Flavobacteriia class of the Bacteroidetes and certain groups of Gammaproteobacteria). Yet, although at low abundance, we also detected the presence of taxa not typically found in bacterioplankton communities such as the Epsilonproteobacteria and members of the candidate division ZB3, particularly during the eruptive stage. These groups are often associated with deep-sea hydrothermal vents or sulfur-rich springs. Both cytometric and sequence analyses showed that once the eruption ceased, evidences of the volcano-induced changes were no longer observed.     

Attraction of Wild Coastal Fishes to an Atlantic Subtropical Cage Fish Farms, Gran Canaria, Canary Islands

We assessed the influence of two commercial fish farms on the local aggregation of coastal wild fishes through a 'post-impact' sampling design at Gran Canaria Island (Canary Islands). At each farm, we established two controls and one impact location and estimated fish abundance bimonthly by means of SCUBA diving. Results provide evidence of local aggregation in the associated fish assemblages around sea-cage fish farms. Dissimilarities between control and impact locations for both fish farms were due to differences on the abundance of a few species. However, we detected significant differences by means of some assemblages between controls in one fish farm, as a consequence of the removal and re-location of cages. Moreover, we also detected significant within location small-scale variability for several fish assemblages around both sea-cages farms. Otherwise, we did not observe any effect of sampling times.     

The occurrence of Ranzania laevis off the Island of Gran Canaria, the Canary Islands, related to sea warming

Catches of the slender sunfish Ranzania laevis were reported off the coastline of the island of Gran Canaria, the Canary Islands, Spain in May-June 2001, apparently associated with a sudden west-east warming process of the sea surface in the central Atlantic.     

Palatine torus in the pre-conquest inhabitants of the Canary Islands.

An unusually high frequency of palatine torus in prehistoric Canary Islands skeletal remains is investigated in terms of population origins, evolutionary forces (gene flow and genetic drift) and environmental effects. Palatine torus frequencies (percent presence) are compared between the Canary Islands sample and skeletal samples from proposed ancestral regions, including northwest Africa, northeast Africa, sub-Saharan Africa, southern Europe, northern Europe and western Asia. The frequency of palatine torus is much higher in the Canary Islands sample (23.8%) than in samples from Northern and sub-Saharan Africa (1.8-6.1%), southern Europe (7.5%) and western Asia (2.1%), but is much lower than in the sample from northern Europe (57.4%). Because biological and archaeological evidence provide strong support for a northwest African origin for indigenous Canary Islands populations, the relatively high occurrence of palatine torus in the Canary Islands populace cannot be explained by an alternative ancestry; rather, it may be best explained by either evolutionary forces such as genetic drift or gene flow, or by environmental forces, such as hard chewing or a heavy dependence on marine foods. Genetic drift and gene flow seem less likely, since frequencies of other dental traits known to be under strong genetic control do not differ greatly between the prehistoric Canary Islands and northwest African samples. Environmental factors such as diet seem the most likely explanation and may include heavy consumption of marine foods, which has been implicated in torus formation.     

Radiation of the genus Dysdera (Araneae, Haplogynae, Dysderidae) in the Canary Islands: The island of Gran Canaria

This study continues studies on the taxonomy and distribution of Dysdera in the Canarian archipelago. Four new species are described: Dysdera andamanae sp. n., D. arabisenen sp. n., D. tibicena sp. n. and D. yguanirae sp. n. Four new synonymies are reported: D. bailadero Wunderlich, 1991 and D. pauciserae Wunderlich, 1991 = Dysdera iguanensis Wunderlich, 1987, D. tamadabaensis Wunderlich, 1991 = D. paucispinosa Wunderlich, 1991; D. sinuosa Wunderlich, 1994 = D. tilosensis Wunderlich, 1991. Six species are redescribed: D. bandamae Schmidt, 1973, D. iguanensis Wunderlich, 1987, D. insulana Simon, 1883, D. paucispinosa Wunderlich, 1991, D. tilosensis Wunderlich, 1991 and D. verneaui Simon, 1883; and neotypes are designated for D. insulana and D. verneaui . The presence of the following species in Gran Canaria is reported for the first time: D. iguanensis , formerly only collected on Tenerife, D. insulana , previously of doubtful location, and D. levipes , known from Tenenfe and La Gomera. Morphological affinities, ecology and distribution of the species are discussed.     

Screening of antimicrobial activities in red, green and brown macroalgae from Gran Canaria (Canary Islands, Spain)

Extracts from 44 species of seaweed from Gran Canaria (Canary Islands, Spain) were screened for the production of antibacterial and antifungal compounds against a panel of gram-negative and gram-positive bacteria, mycobacteria, yeasts and fungi. A total of 28 species displayed antibacterial activity, of which six also showed antifungal activity. Asparagopsis taxiformis and Cymopolia barbata were the species with the strongest activities against the broadest spectrum of target microorganisms. All the species with antibacterial activity were active against gram-positive bacteria, whereas only two species, A. taxiformis and Osmundea hybrida, were active against mycobacteria. The production of secondary metabolites with antimicrobial activities by the macroalgae was also studied under different conditions, although no common trend for bioactivity was observed.     

Mitochondrial DNA, ecology and morphology: interpreting the phylogeography of the Nesotes (Coleoptera: Tenebrionidae) of Gran Canaria (Canary Islands)

The genus Nesotes (Coleoptera: Tenebrionidae) is represented in the Canary Islands by 19 endemic species, the majority of which are single island endemics. Nesotes conformis and N. fusculus are described on four and three islands, respectively, but each forms a paraphyletic assemblage between Gran Canaria and the other islands. The other described species for Gran Canaria are N. quadratus, N. lindbergi and N. piliger. Thirty-six individuals representing the five species on Gran Canaria have been sequenced for 675 bp of the mitochondrial DNA (mtDNA) cytochrome oxidase II gene. Neighbour-joining analysis of maximum likelihood distances resulted in five distinct mtDNA lineages for N. quadratus, two of which also include mitotypes of N. conformis. Each of the other three species is found on only one mtDNA lineage. We propose from the molecular data that differentiation in a widespread N. quadratus-type ancestor was followed by morphological adaptation to coastal, pine and laurel forest habitats.     

Breeding strategies of RavensCorvus corax in an oceanic island ecosystem (El Hierro, Canary Islands)

The breeding population of Ravens on El Hierro consists of between 99 and 120 pairs. Most territories were found at altitudes of 600 metres a. s. l. or lower. Altitude had an important effect on the early stages of clutches, especially in the lower zones or in those at heights less than 900 metres a. s. l. There were no great differences in the timing of nesting in comparison with continental areas. Clutch size and breeding success were lower than in practically all continental zones, which suggests a relationship to the limited resource capacity of island ecosystems.

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Zusammenfassung Auf El Hierro (Kanarische Inseln) brüten 88 bis 120 Paare Kolkraben. Die meisten Brutterritorien liegen bei 600 m ü. NN oder tiefer. Legebeginn und Bruterfolg variieren mit der Meereshöhe. Die Brutperiode weicht nicht von den Werten kontinentaler Populationen ab. Gelegegröße und Bruterfolg waren jedoch geringer als in allen bisher untersuchten kontinentalen Populationen; dies ist wahrscheinlich auf limitierte Ressourcen des Inselökosystems zurückzuführen.