Myotragus Research Articles

The brain of Myotragus balearicus, an insular bovid from the Balearics

ABSTRACT Myotragus balearicus is the terminal species of a Caprinae lineage that inhabited the Balearic Islands since the Messinian. Myotragus balearicus had a relatively small brain, reported to be half the size of a contemporary bovid of similar size. This study presents a reassessment of its brain size and anatomy. We demonstrate that the brain of M. balearicus is only 17% smaller when compared to Late Miocene taxa. Since the ancestors of M. balearicus were isolated on the Balearics in the Late Miocene, we deduce that the small brain size of M. balearicus is a feature largely retained from its continental ancestor and only partially the result of geographic isolation. The reduction in brain size can be attributed to reduction of the occipital region. We hypothesise that neuroanatomical changes during the evolutionary process of dwarfism were likely influenced by the absence of ecologically relevant predators.

An overview of Upper Pleistocene coastal deposits on Mallorca island

This review paper delves into the geological history of Mallorca, focusing on the Middle to Late Pleistocene period and its impact on the landscape and climate of the island. The Quaternary, particularly, the Last Interglacial, represents a relatively short timeframe on the global chronological scale, yet it is notable for its climatic instability and complex alternation of glacial and interglacial phases, leading to fluctuations in sea levels. During the last interglacial, millennial-scale fluctuations, known as Dansgaard–Oeschger and Heinrich events, occurred. Aeolianites are thought to have formed during periods of sparse vegetation cover and abundant sediment availability from the sea bed or platform (Heinrich events), while colluvial deposits and paleosols are believed to represent periods of reduced sediment supply and enhanced pedogenesis (Dansgaard–Oeschger events). These different deposits reflect climatic shifts and sea-level changes, offering insights into the environmental history of the island. Fossil evidence, including Strombus bubonius (currently known as Thetystrombus lauts) or “Senegalese hosts,” reveals past warm climatic fluctuations, particularly during the Last Interglacial. Myotragus balearicus exemplifies evolutionary adaptation and isolation on the island, offering a unique perspective on its paleontological legacy. The integration of stratigraphic characteristics and literature research on Optically Stimulated Luminescence (OSL) dating techniques provides a comprehensive temporal framework, spanning from Marine Isotope Stage 6 (MIS 6) to Marine Isotope Stage 2 (MIS 2), enabling the precise dating of geological events and a stratigraphic correlation.

Landscape and fuel management in the context of prehistoric and historical occupations of Cova des Moro (Manacor, Mallorca, Spain)

In this paper, the first results of charcoal analyses carried out at Cova des Moro (Manacor, Mallorca, Spain) are presented. This cave is an archaeological but also palaeontological site that provides information on endemic fauna (the extinct caprine Myotragus balearicus) before the arrival of humans and, later, the relationship between the first farmers and the landscape. Several human occupations in the cave have been documented, from the Chalcolithic (end of the 3rd millennium cal BC), the Bronze Age (2nd millennium cal BC) and, finally, the Almohad period (13th century AD), during which the cave was used for different purposes.The first results of charcoal analyses at Cova des Moro provide information about the natural plant communities exploited by humans for comparison with later sequences, enabling us to evaluate how humans managed this territory over time. The results point to the exploitation of Mediterranean woodlands with wild olive (Olea europaea), mastic (Pistacia lentiscus), green olive tree (Phillyrea), Aleppo pine (Pinus halepensis), rosemary (Rosmarinus officinalis), juniper (Juniperus) and rockrose species (Cistus), among others; these taxa would become the main elements of Mallorca's coastal landscape in later times, and it has been proven that they would already have been present as the island's natural flora at the time humans arrived there.

Phenolic metabolites from 5,000-year-old coprolites of Myotragus balearicus, an extinct insular bovid

To date, the identification of polyphenols in the archaeological and palaeontological record has been limited. Here, we demonstrate for the first time the presence of flavonoid and phenolic metabolites from non-mineralised coprolites belonging to a non-human mammal species. Myotragus balearicus is the last species of a bovid lineage that became extinct during the Holocene in the western Mediterranean basin. In this work, we characterize the phenolic metabolites of M. balearicus coprolites for the first time. The chemical analysis of coprolites revealed the presence of flavonoids, such as flavones and flavonols. Moreover, the detection of conjugates of hydroxyphenylvaleric, hydroxyphenylpropionic and hydroxyphenylacetic acids, among other catabolites of flavan-3-ols, suggested the presence of the latter structures in plants of the Myotragus diet. The lack of other flavonoids such as isoflavones, flavanones, dihydroflavonols, anthocyanidins and chalcones (or its specific metabolite biomarkers) may suggest a narrow food web in Myotragus, although it may also indicate a complete microbial metabolism during the gut passage or even post-depositional microbial alterations or diagenetic transformations. Based on the phenolic metabolites identified by mass spectrometry, the extinct Myotragus did not possess a flavonoid metabolism distinct from that reported in extant mammals, despite the drastic changes suffered under insularity conditions that involved its life history.

Tolerance to severe browsing of three shrub species on Mediterranean islands

Buxus balearica Lam., Ephedra fragilis Desf., and Juniperus oxycedrus L. are three Pre-Mediterranean shrubs that have become scarce in the Balearic Islands probably due to a climatic change and the anthropogenic activities during the second half of the Holocene. In addition, an endemic artiodactyl, Myotragus balearicus, exerted browsing pressure on these species for thousands of years, and after it disappeared domestic goats were introduced by humans. Adaptations that enable these plants to resist grazing are structural or chemical; however, there is no information about whether their defenses are only constitutive or also inducible. Currently, the mountain ranges of Majorca Island are extensively occupied by feral goats, and a possible increase in the stocking rates could affect the survival of these plant species. The aim of this study was to evaluate and compare the effects of simulated severe browsing on the re-growth capacity and chemical composition of these species in order to determine their tolerance to herbivory. We sampled and compared structural and chemical variables of saplings submitted to two pruning intensities for each species.The results showed that all three species could maintain their growth rate and biomass ratios under simulated herbivory. Sprout production was also stimulated in all them. E. fragilis and B. balearica increased phenolic content after pruning, and E. fragilis also increased the condensed tannins. Pruning treatments did not trigger induction of phenolic content in J. oxycedrus, which could be considered as a constitutive defense. It is noteworthy that alkaloids in E. fragilis decreased with the treatments, which may contribute to preventing a possible addiction to these compounds, and thus reduce browsing damage.The responses induced by pruning show that these species are very tolerant to a level of herbivory, which could indicate a good adaptation to browsing pressure, exerted since the Pleistocene by Myotragus balearicus, and followed by goats during the last millennia. This is especially relevant in Mediterranean islands, such as the Balearic Islands, where practices for conserving relict plant species are based on feral herbivore exclusion.

Unraveling the phylogenetic relationships of the extinct bovid Myotragus balearicus Bate 1909 from the Balearic Islands

Myotragus balearicus was the last living representative of an extinct caprine lineage endemic to the Balearic Islands (Western Mediterranean), which became extinct following the arrival of humans around 4300 years ago. The tribal attribution of Myotragus based on morphological analyses has been complicated due to its unusual morphological characteristics, though most studies agree on its inclusion within Caprini (also including modern sheep and goats). Analyses of short fragments of ancient mitochondrial DNA have suggested Ovis (comprising extant sheep) as sister taxon to Myotragus, although other authors have suggested alternative placements within Caprini using the same data. In the present study, we present a complete high-depth mitochondrial genome of M. balearicus, which allowed us to test the previously proposed Ovis/Myotragus clade and revealed a closer relationship between Myotragus and the takin (Budorcas taxicolor). The results of our molecular clock analyses suggested that the split between Myotragus and Budorcas occurred around 7.1 Mya, which is compatible with the arrival of the ancestor of Myotragus to the Balearic Islands during the Messinian Salinity Crisis (5.97–5.33 Mya). We also conducted a preliminary phylogeographic analysis of M. balearicus in Mallorca, which revealed weak spatial and temporal structure within the population during the Holocene.

Non-native Mammals Are the Main Seed Dispersers of the Ancient Mediterranean Palm Chamaerops humilis L. in the Balearic Islands: Rescuers of a Lost Seed Dispersal Service?

Megafauna extinctions often lead to the disruption of plant-animal interactions, such as the seed-disperser mutualisms, which might entail severe consequences for plant populations and entire communities. Interestingly, the contemporary persistence of anachronistic plant species might be possible thanks to surrogate dispersers or seed dispersal “rescuers”. We know very little on how these relevant functional replacements are contributing to the performance of present-day plant-frugivore networks. The dwarf palm Chamaerops humilis L. is a Mediterranean endemism with fleshy fruits and typically dispersed by mammals. Despite its ecological importance and wide distribution in some of the Mediterranean islands, no information exists about its seed dispersal on these depauperated-fauna systems. In this study, we aim at identifying and quantifying the relative importance of introduced frugivores on the island of Mallorca (Balearic Islands), where no native terrestrial mammals exist. Specifically, we assess for the first time the seed dispersal effectiveness (SDE) for C. humilis on islands; we evaluate the quantitative component by fecal and regurgitation sampling surveys, and the qualitative component by means of seed germination experiments and seedling growth measures. Introduced goats (Capra hircus L.) and pine martens (Martes martes L.) were the local mammal fruit consumers of C. humilis identified in our study sites. Results suggest that goats are much more important quantitatively than pine martens, due to the high number of fruits handled in each foraging bout and their extremely high abundance on the island. However, pine marten-ingested seeds showed the highest final seedling emergence success and seedling growth, thus its qualitative contribution on C. humilis seed dispersal is higher than that of goats. Overall, SDE was almost 9-fold higher for goats than for pine martens. We conclude that these two non-native mammal species are effective seed dispersers of C. humilis in this and probably other Mediterranean islands, where humans led to the extinction of its native seed dispersers, as it was probably the case of the goat-like Myotragus balearicus in the Balearic Islands.

Paleoparasitological analysis of the extinct Myotragus balearicus Bate 1909 (Artiodactyla, Caprinae) from Mallorca (Balearic Islands, Western Mediterranean)

Myotragus balearicus (Artiodactyla, Caprinae) is an extinct caprine endemic of the Eastern Balearic Islands or Gymnesics (i.e., Mallorca, Menorca and surrounding islets, Western Mediterranean Sea). In spite of its small size, c. 50cm height at the shoulder, it was the largest mammal inhabiting these islands until the human arrival, and it had peculiar short legs and frontal vision. It disappeared between 2830 and 2210calBCE. The coprolites here studied were recovered from Cova Estreta, in Pollença, Mallorca. The samples were subjected to microscopic examination and enzyme-linked immunosorbent assays (ELISA) for E. histolytica/E. dispar, Giardia intestinalis and Cryptosporidium parvum. This study provides new paleoparasitological data from an extinct animal species of the Holocene period. The microscopy revealed one sample containing uninucleated-cyst of Entamoeba sp., whereas ELISA detected nine positive samples for Cryptosporidium sp. The finding of these protozoans can help in the discussion of its extinction cause and demonstrates the antiquity and the evolutionary history of host-parasite relationships between protozoa and caprines since the Messinian.

Closing the gap: New data on the last documentedMyotragusand the first human evidence on Mallorca (Balearic Islands, Western Mediterranean Sea)

The chronology of the extinction of the Balearic fossil bovid Myotragus balearicus in Mallorca and Menorca has been under discussion since its discovery in 1909, and especially in the last decades, thanks to the radiocarbon dates that have been obtained from several deposits of the island of Mallorca. Here, we present new radiocarbon dates of M. balearicus bones (including the most recent date ever obtained for the species, 4035 ± 32 BP, 2830–2470 cal. BC) that together with a newly published radiocarbon date for the evidence of the first human presence in the island (introduced Caprinae bone, 3884 ± 36 BP; 2470–2210 cal. BC) allow us to reduce the uncertainty period for the Myotragus extinction (UPME) in Mallorca from 1660 to 620 years ( p > 95%) or even to 350 years ( p > 90%) and to reject the hypotheses suggesting a climate change–driven (i.e. non-human) extinction of the species. This new scenario points to the causal relationship between the first human arrival and the M. balearicus extinction. The chronological gap between the earliest documented M. balearicus and the first documented human presence represents one of the shortest time periods documented between endemic megafauna and humans on any Mediterranean island.

Stomatal density and stomatal index of fossil Buxus from coprolites of extinct Myotragus balearicus Bate (Artiodactyla, Caprinae) as evidence of increased CO2 concentration during the late Holocene

Stomatal density of plants may vary depending on environmental factors, such as CO2 concentration. Under the current atmospheric conditions, it is expected that leaves have different stomatal density than they had hundreds or thousands of years ago, due to the rise in CO2 in the atmosphere. Coprolites of the extinct Myotragus balearicus from Cova Estreta (Pollença, Mallorca), with a radiocarbon age of 3775–3640 cal. bc, have been used to study the diet of this bovid. A significant amount of epidermal fragments of Buxus was found in the faecal material. Three coprolites were used to estimate the stomatal density and stomatal index of Buxus epidermal fragments from this period. Samples of the endangered Buxus balearica, the sole species of Buxus currently present on Mallorca, and samples of the Buxus sempervirens, present in the nearest mainland, were also collected in different locations. Leaves were examined using microscopy to determine and compare the stomatal density and stomatal index between current plant material and coprolite material. The results indicated a higher value for stomatal index (12.71) and stomatal density (297.61 stomata/mm2) in leaves from the coprolites versus leaves of the living B. balearica and B. sempervirens species (7.99 and 227.77 stomata/mm2 respectively). These results could provide a palaeobotanic evidence of a change in atmospheric CO2 concentration since mid-Holocene in the Mediterranean basin.

Analysis of coprolites from the extinct mountain goat Myotragus balearicus

Humans colonized the Balearic Islands 5–4ka ago. They arrived in a uniquely adapted ecosystem with the Balearic mountain goat Myotragus balearicus (Bovidae, Antilopinae, Caprini) as the only large mammal. This mammal went extinct rapidly after human arrival. Several hypotheses have been proposed to explain the extinction of M. balearicus. For the present study ancient DNA analysis (Sanger sequencing, Roche-454, Ion Torrent), and pollen and macrofossil analyses were performed on preserved coprolites from M. balearicus, providing information on its diet and paleo-environment. The information retrieved shows that M. balearicus was heavily dependent on the Balearic box species Buxus balearica during at least part of the year, and that it was most probably a browser. Hindcast ecological niche modelling of B. balearica shows that local distribution of this plant species was affected by climate changes. This suggests that the extinction of M. balearicus can be related to the decline and regional extinction of a plant species that formed a major component of its diet. The vegetation change is thought to be caused by increased aridity occurring throughout the Mediterranean. Previous hypotheses relating the extinction of M. balearicus directly to the arrival of humans on the islands must therefore be adjusted.

Dietary divergence in space and time – Lessons from the dwarf-goat Myotragus balearicus (Pleisto-Holocene, Mallorca, Spain)

Newly colonised, isolated habitats, like islands, provide diverse niches to be filled and are prone to facilitate ecological separation which might lead to an adaptive radiation. Examples of such radiations can be found in the Mediterranean for the genera Candiacervus (Crete), Nesogoral (Sardinia) and Hoplitomeryx (Gargano). A different strategy to cope with limited resources on islands is generalism. We test whether populations of the endemic bovid Myotragus balearicus from two sites and Pleistocene as well as Holocene levels on Mallorca island displays ecological separation indicated by diet, or whether the species shifted its dietary trait towards generalism. We expect to find either: (1) dietary divergence in space and time (between sites and stratigraphic levels), which would indicate niche partitioning and/or a shift in dietary traits due to environmental influences; or (2) dietary congruence in a less specialised, generalistic dietary strategy in space and time which would indicate a flexible trait to cope with instable resource availability. We compare individuals from a fossil assemblage at a northern site and one assemblage from the eastern coast in terms of their dietary traits. Traits are reconstructed using dental dietary proxies, complementary in time scale and resolution. (1) 3D-dental topometry and (2) enamel surface texture analysis. Data suggest that individuals from both assemblages of M. balearicus behaved as variable browse dominated intermediate feeders. We thus conclude that the observed variability relates to a shift towards generalism as a subsistence strategy. We consider hypsodonty the pre-adaptation for this life style that enabled M. balearicus to exploit almost any food source in its energetically restricted island habitat.

First Fossil Evidence for the Advance of Replacement Teeth Coupled with Life History Evolution along an Anagenetic Mammalian Lineage

In mammals that grow up more slowly and live longer, replacement teeth tend to appear earlier in sequence than in fast growing mammals. This trend, known as ‘Schultz's Rule’, is a useful tool for inferring life histories of fossil taxa. Deviations from this rule, however, suggest that in addition to the pace of life history, ecological factors may also drive dental ontogeny. Myotragus balearicus is an extinct insular caprine that has been proved to be an excellent test case to correlate morphological traits with life history. Here we show that Myotragus balearicus exhibits a slow signature of dental eruption sequence that is in agreement with the exceptionally slow life history of this species, thus conforming to ‘Schultz's Rule’. However, our results also show an acceleration of the absolute pace of development of the permanent incisors in relation to that of the posterior teeth. The rodent-like incisors of Myotragus balearicus erupted early not only in relative but also in absolute terms (chronological age), suggesting that feeding characteristics also plays an important role in dental ontogeny. This is in agreement with ecological hypotheses based on primates. Our study documents a decoupling of the pace of development of teeth in mammals that is triggered by different selection pressures on dental ontogeny. Moreover, we show that Myotragus kopperi from the early Pleistocene (a direct ancestor of the late Pleistocene-Holocene M. balearicus) follows the pattern of first incisor replacement known in living bovids. Hence, the advance in the eruption sequence of the first incisors occurs along the Myotragus evolutionary lineage over a period of about 2.5 Myr. To our knowledge, this is the first fossil evidence of an advance of the emergence of the permanent first incisor along an anagenetic mammalian lineage.

Indications for a dietary change in the extinct Bovid genus Myotragus (Plio-Holocene, Mallorca, Spain)

Evolution in isolated island has shaped a variety of endemic taxa with outstanding characteristics. Amongst them is the extinct bovid genus Myotragus, endemic to Mallorca and Menorca Island, for which six succeeding species have been described: M. palomboi, M. pepgonellae, M. antiquus, M. kopperi, M. batei and M. balearicus. Myotragus has developed special cranial and post-cranial adaptations to meet the specific ecological demands of its insular habitat, like progressive dwarfing and fused limb elements. During its evolution, the dentition of Myotragus underwent subsequent changes: firstly a reduction in the number of teeth, and secondly an increase in hypsodonty. The ecological conditions inducing this dental evolution, especially Myotragus’ diet, remain unknown. In this study, methods of 3D-dental topometry, enamel surface texture analysis according to ISO/FDIS 25178-2, and Scale-Sensitive Fractal Analysis (SSFA) are applied in order to infer palaeodiets of M. pepgonellae, M. kopperi, M. batei and M. balearicus, and to test the hypothesis that a dietary change may have occurred in the Myotragus lineage which relates to gradual morphological changes on upper second molars. We detect changes in the enamel/dentin ratio, enamel ridge length and enamel surface area within the lineage. Furthermore, Myotragus balearicus has enamel surface texture characteristics also present in extant browsing ungulates, while the three antecedent Myotragus species show an enamel surface texture signal similar to extant grazers. These results suggest a dietary change and are interpreted as a successive adaptation to limited resources in an isolated, insular environment. They can either be a consequence of a change in plant community structure or a successive expansion of Myotragus’ dietary range due to increased intraspecific competition.

A new african fossil caprin and a combined molecular and morphological bayesian phylogenetic analysis of caprini (Mammalia: Bovidae)

Given that most species that have ever existed on Earth are extinct, no evolutionary history can ever be complete without the inclusion of fossil taxa. Bovids (antelopes and relatives) are one of the most diverse clades of large mammals alive today, with over a hundred living species and hundreds of documented fossil species. With the advent of molecular phylogenetics, major advances have been made in the phylogeny of this clade; however, there has been little attempt to integrate the fossil record into the developing phylogenetic picture. We here describe a new large fossil caprin species from ca. 1.9-Ma deposits from the Middle Awash, Ethiopia. To place the new species phylogenetically, we perform a Bayesian analysis of a combined molecular (cytochrome b) and morphological (osteological) character supermatrix. We include all living species of Caprini, the new fossil species, a fossil takin from the Pliocene of Ethiopia (Budorcas churcheri), and the insular subfossil Myotragus balearicus. The combined analysis demonstrates successful incorporation of both living and fossil species within a single phylogeny based on both molecular and morphological evidence. Analysis of the combined supermatrix produces superior resolution than with either the molecular or morphological data sets considered alone. Parsimony and Bayesian analyses of the data set are also compared and shown to produce similar results. The combined phylogenetic analysis indicates that the new fossil species is nested within Capra, making it one of the earliest representatives of this clade, with implications for molecular clock calibration. Geographical optimization indicates no less than four independent dispersals into Africa by caprins since the Pliocene.

Fragmentation of Contaminant and Endogenous DNA in Ancient Samples Determined by Shotgun Sequencing; Prospects for Human Palaeogenomics

BackgroundDespite the successful retrieval of genomes from past remains, the prospects for human palaeogenomics remain unclear because of the difficulty of distinguishing contaminant from endogenous DNA sequences. Previous sequence data generated on high-throughput sequencing platforms indicate that fragmentation of ancient DNA sequences is a characteristic trait primarily arising due to depurination processes that create abasic sites leading to DNA breaks.Methodology/Principals FindingsTo investigate whether this pattern is present in ancient remains from a temperate environment, we have 454-FLX pyrosequenced different samples dated between 5,500 and 49,000 years ago: a bone from an extinct goat (Myotragus balearicus) that was treated with a depurinating agent (bleach), an Iberian lynx bone not subjected to any treatment, a human Neolithic sample from Barcelona (Spain), and a Neandertal sample from the El Sidrón site (Asturias, Spain). The efficiency of retrieval of endogenous sequences is below 1% in all cases. We have used the non-human samples to identify human sequences (0.35 and 1.4%, respectively), that we positively know are contaminants.ConclusionsWe observed that bleach treatment appears to create a depurination-associated fragmentation pattern in resulting contaminant sequences that is indistinguishable from previously described endogenous sequences. Furthermore, the nucleotide composition pattern observed in 5′ and 3′ ends of contaminant sequences is much more complex than the flat pattern previously described in some Neandertal contaminants. Although much research on samples with known contaminant histories is needed, our results suggest that endogenous and contaminant sequences cannot be distinguished by the fragmentation pattern alone.

New equations for body mass estimation in bovids: Testing some procedures when constructing regression functions

Body mass is an important attribute of organisms. For extinct species, body mass is usually predicted from allometric equations relating body mass with some variable(s) from the skeleton in extant species. However, even for extant species, individual associated body mass data are scarce, and mean body mass values taken from literature are commonly used when developing regressions. In this paper we evaluate the correlation between three external body measurements and the body mass of bovids with associated body mass, in order to find those variables adequate for body mass estimation in this family. The importance of using individuals with associated body weight to develop regressions was analyzed, as well as the use of Phylogenetic Generalized Least Squares (PGLS) and weighting procedures. Six equations were obtained with those variables suitable for body mass estimation (head-body length and thorax circumference), three by means of OLS and three by PGLS. Both phylogenetic and non-phylogenetic procedures render the same mean prediction error. The use of weighting procedures does not improve the predictive capacity of the equations. The percentage of prediction error (%PE) was lower than in previous works in ungulates (10–14%). The three equations were repeated with literature body mass data, and in all cases the mean %PE was around 50% higher than with associated body mass data. The multiple regression is strongly recommended for body mass estimation, when both variables are available. Body mass was estimated for three bovid species: Bos primigenius, Myotragus balearicus and Pseudoryx nghetinhensis.

Tracing the evolution of fitness components in fossil bovids under different selective regimes

Hard tissue histology is a valuable tool to reconstruct life history traits in fossil ungulates. We estimated certain fitness components (age at weaning, age at maturity, life span and generation time) in two fossil bovids that evolved under different selective regimes, the insular Myotragus balearicus and the continental Gazella borbonica. Our results provide evidence that the mainland G. borbonica conforms to the predictions for ungulates of similar body size. However, the insular M. balearicus does not fit predictions from body mass scaling, as it shows an important delay in age at weaning and, especially, in age at first reproduction. The considerable differences in the onset of these fitness components reflect the differences in resource availability and in extrinsic mortality that exist between insular and continental ecosystems. The significant delay in life history traits in Myotragus most likely resulted in severe constraints on the ability of this insular mammal to respond to ecological disturbances.

Enamel microstructure in the fossil bovid Myotragus balearicus (Majorca, Spain): Implications for life-history evolution of dwarf mammals in insular ecosystems

The causes underlying the evolution of insular dwarfs and giants are a matter of ongoing debate. Because body size is among the principle life history traits, recent works aim to understand the evolution of insular dwarfs in the framework of life history theory. However, the hypotheses put forward so far are conflicting. Early studies, suggested that dwarfing is a consequence of selection for an increased reproduction associated to an accelerated life history (formerly r-selection). Recent work, however, based on the analysis of bone histology of the fossil insular dwarf bovid Myotragus balearicus (Balearic Islands, Spain), concluded that dwarfing on islands results from a decrease in growth rate associated to a slow life history (formerly K-selection) in response to selective forces peculiar to insular conditions. In the present work, we reconstruct the schedule of certain life history traits by estimating the rate of dental development and eruption times in M. balearicus and, for comparisons, in an extant caprine (Ovis aries). We used histological techniques to calculate crown formation time, daily secretion rate and crown extension rate, in the lower molars. Eruption pattern in M. balearicus was analysed through the radiological images of an ontogenetic series of mandibles. Our results show that dental crowns grew at slower rates and the period of crown formation was more extended in the dwarfed fossil bovid than in other extant caprines, resulting in dental development and eruption time that doubles that of extant bovids of similar body size. This suggests an important delay in life history schedules. Concordant with the delayed dental development, the striking hypsodonty of Myotragus is indicative of an extended lifespan. These results, together with previous findings from long bone histology, provide empirical evidence for a shift towards a slow life history in this insular dwarfed mammal. Density-dependent resource limitation is hypothesized as the main trigger of the life history and body size evolution of Myotragus.

Marès Quarries on the Majorcan Coast (Spain) as Geological Heritage Sites

Mares is a soft rock, generally pale-coloured rock, composed mainly of bioclastic calcareous sandstone which ranges in age from the Late Miocene to the Quaternary, although it dates predominantly from the Pleistocene. This rock was traditionally the main material for construction on the island, with the Palma Cathedral being a classic example. There are numerous mares quarries on the eastern and southern coast of Majorca, some of which are very well exposed in the cliffs. The stone is quarried in large blocks which are later divided into smaller ones. This quarrying process creates deep, vertical quarry walls orientated, both parallel and perpendicular to the coast, which gives an excellent exposure of the rock and clear views of its internal structure. In 2006, the first inventory of geosites on the Balearic Islands was carried out with the aim of defining the geological and hydrogeological heritage in the region. Of the 35 geosites inventoried and catalogued on the island of Majorca, two of them are mares quarries: Estret des Temps on the Santanyi coast and Es Carnatge on the coast of Palma. Both are representative of Pleistocene aeolianites, with excellent exposure of the sets of cross-bedding, while the Estret des Temps quarry also contains noteworthy exposures of hoof prints of Myotragus balearicus, a small endemic goat which became extinct with the arrival of the first human inhabitants of the island, around 7,000 BC. In this study, we propose the inclusion of a new site in the geosites inventory, the Roman quarry of Es Molar de Cala Pi in Llucmajor, where an exceptional sequence of Late-Miocene beaches facies can be observed, including a coquina with large-scale and high-angle cross-bedding and anemone tubes at the base of the quarry. The sequence is crowned by a system of Pleistocene palaeodunes. Such exposure conditions and facies sedimentological variety, coupled with the representativeness of the record, make this quarry a unique site for the study of the Neogene and Quaternary on Majorca