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See detailOrigin and evolution of sound production in Serrasalmidae
Melotte, Geoffrey ULiege; Raick, Xavier ULiege; Vigouroux, Régis et al

in Biological Journal of the Linnean Society (2019)

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See detailFunctional diversity in biters: the evolutionary morphology of the oral jaw system in pacus, piranhas and relatives (Teleostei: Serrasalmidae)
Huby, Alessia ULiege; Lowie, Aurélien ULiege; Herrel, Anthony et al

in Biological Journal of the Linnean Society (2019)

Serrasalmid fishes form a highly specialized group of biters that show a large trophic diversity, ranging from pacus able to crush seeds to piranhas capable of cutting flesh. Their oral jaw system has ... [more ▼]

Serrasalmid fishes form a highly specialized group of biters that show a large trophic diversity, ranging from pacus able to crush seeds to piranhas capable of cutting flesh. Their oral jaw system has been hypothesized to be forceful, but variation in bite performance and morphology with respect to diet has not previously been investigated. We tested whether herbivorous species have higher bite forces, larger jaw muscles and more robust jaws than carnivorous species. We measured in vivo and theoretical bite forces in 27 serrasalmid species. We compared the size of the adductor mandibulae muscle, the jaw mechanical advantages, the type of jaw occlusion, and the size and shape of the lower jaw. We also examined the association between bite performance and functional morphological traits of the oral jaw system. Contrary to our predictions, carnivorous piranhas deliver stronger bites than their herbivorous counterparts. The size of the adductor mandibulae muscle varies with bite force and muscles are larger in carnivorous species. Our study highlights an underestimated level of functional morphological diversity in a fish group of exclusive biters. We provide evidence that the trophic specialization towards carnivory in piranhas results from changes in the configuration of the adductor mandibulae muscle and the lower jaw shape, which have major effects on bite performance and bite strategy. [less ▲]

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See detail‘Homemade’: the phenotypic diversity of coral reef damselfish populations is driven by the local environment
Chen, Chia-Ting; Robitzch, Vanessa; Sturaro, Nicolas ULiege et al

in Biological Journal of the Linnean Society (2019), 127

Documenting phenotypic variation among populations is crucial for our understanding of micro-evolutionary processes. To date, the quantification of trophic and morphological variation among populations of ... [more ▼]

Documenting phenotypic variation among populations is crucial for our understanding of micro-evolutionary processes. To date, the quantification of trophic and morphological variation among populations of coral reef fish at multiple geographical scales remains limited. This study aimed to quantify diet and body shape variation among four populations of the damselfish Dascyllus abudafur living in different environmental conditions from the central Red Sea and from Madagascar. Stomach content analyses showed that one adaptive response of D. abudafur inhabiting turbid waters is a trophic shift from almost exclusive zooplanktivory to a diet consisting of planktonic and benthic prey. Our morphometric data reveal differences in cephalic profile and body shape among populations, in agreement with this variation in trophic strategy. Isotopic diversity and body shape disparity vary among populations and we thus demonstrate that coral reef fish populations are not equal in terms of phenotypic diversity among sites and regions. Finally, our comparative analysis reveals that the main axes of body shape variation among populations are shared at both small (Red Sea sites) and large (Madagascar and Red Sea sites) spatial scales. This study raises new questions about the factors governing the direction of response to selection in this fish species. [less ▲]

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See detailConsequence of past anthropogenic forest fragmentation on the genetic structure of European mammals: the example of the edible dormouse (Glis glis)
Michaux, Johan ULiege; Hurner, H.; Krystufek, B et al

in Biological Journal of the Linnean Society (2019), 126 (4)

The genetic structure of forest animal species may allow the spatial dynamics of the forests themselves to be tracked. Two scales of change are commonly discussed: changes in forest distribution during ... [more ▼]

The genetic structure of forest animal species may allow the spatial dynamics of the forests themselves to be tracked. Two scales of change are commonly discussed: changes in forest distribution during the Quaternary, due to glacial/ interglacial cycles, and current fragmentation related to habitat destruction. However, anthropogenic changes in forest distribution may have started well before the Quaternary, causing fragmentation at an intermediate time scale that is seldom considered. To explore the relative role of these processes, the genetic structure of a forest species with narrow ecological preferences, the edible dormouse (Glis glis), was investigated in a set of samples covering a large part of its Palaearctic distribution. Strong and complex geographical structure was revealed from the use of microsatellite markers. This structure suggests that fragmentation occurred in several steps, progressively splitting the ancestral population into peripheral isolated ones. The fact that this structure postdates post-glacial recolonization, together with dating based on microsatellite data, supports the hypothesis that the differentiation was recent, starting around 9000 years ago, and took place stepwise, possibly up to Medieval times. This complements a classic phylogeographical interpretation based on the effect of past climate change, and supports the role of anthropogenic deforestation as a trigger of recent intraspecific differentiation. [less ▲]

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See detailFood properties influence grasping strategies in strepsirrhines
Peckre, Louise; Fabre, Anne-Claire; Hambuckers, Julien ULiege et al

in Biological Journal of the Linnean Society (2019)

Though hand-grasping is ubiquitous in primate species, its origins remain uncertain. This is in part because uncertainty about hand skills and grasping strategies persists in strepsirrhines, a ... [more ▼]

Though hand-grasping is ubiquitous in primate species, its origins remain uncertain. This is in part because uncertainty about hand skills and grasping strategies persists in strepsirrhines, a monophyletic group of primates located near the base of the primate tree. In this study, we report and discuss our observations of the different grasping strategies adopted by 85 captive individuals belonging to 22 species of strepsirrhines during grasping of food items having different size and consistency. Our results indicate that even though strepsirrhines do not present variability in their hand-grip types (sole whole-hand power-grip), they are able to adjust their grasping strategy depending on the food properties. Notably, they use the mouth when more precision is needed (i.e. to grasp small items). Moreover, grasping strategies adopted for big items differ depending on food consistency, revealing a new potential essential factor to consider in future research on grasping abilities. We believe that by looking across this important set of species in unconstrained standardized conditions, this study provides valuable insight for further comparative research discussing the potential selective pressures involved in the evolution of hand-grasping. [less ▲]

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See detailNonreceding hare lines: Genetic continuity since the late pleistocene in european mountain hares (Lepus timidus)
Smith, S.; Sandoval-Castellanos, E.; Lagerholm, V. K. et al

in Biological Journal of the Linnean Society (2017), 120(4), 891-908

Throughout time, climate changes have caused substantial rearrangements of habitats which have alternately promoted and disfavoured different types of taxa. At first glance, the mountain hare (Lepus ... [more ▼]

Throughout time, climate changes have caused substantial rearrangements of habitats which have alternately promoted and disfavoured different types of taxa. At first glance, the mountain hare (Lepus timidus) shows the typical hallmarks of a cold-adapted species that has retreated to refugia since the onset of the current Holocene interglacial. In contrary to expectations, however, the species has a high contemporary genetic diversity with no clear differentiation between geographically isolated populations. In order to clarify the phylogeographic history of European mountain hares, we here analysed ancient DNA from the glacial populations that inhabited the previous midlatitude European tundra region. Our results reveal that the Ice Age hares had similar levels of genetic variation and lack of geographic structure as observed today, and the ancient samples were intermingled with modern individuals throughout the reconstructed evolutionary tree. This suggests a temporal genetic continuity in Europe, where the mountain hares were able to keep pace with the rapid changes at the last glacial/interglacial transition and successfully track their shifting habitat to northern and alpine regions. Further, the temporal demographic analyses showed that the species’ population size in Europe appears to have been tightly linked with palaeoclimatic fluctuations, with increases and declines occurring during periods of global cooling and warming, respectively. Taken together, our results suggest that neither habitat shifts nor demographic fluctuations have had any substantial impact on the genetic diversity of European mountain hares. This remarkable resilience, which contrasts to a majority of previously investigated coldadapted species, is likely due to its generalist nature that makes it less vulnerable to environmental changes. © 2016 The Linnean Society of London. [less ▲]

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See detailPost-glacial colonization of Europe by the wood mouse, Apodemus sylvaticus: evidence of a northern refugium and dispersal with humans
Herman, Jeremy; Johannesdottir, Frija; Jones, Eleanor et al

in Biological Journal of the Linnean Society (2016)

The wood mouse Apodemus sylvaticus is an opportunistic rodent that is found throughout most of the European mainland. It is present on many islands around the margins of the continent and in northern ... [more ▼]

The wood mouse Apodemus sylvaticus is an opportunistic rodent that is found throughout most of the European mainland. It is present on many islands around the margins of the continent and in northern Africa. The species has been the subject of previous phylogeographical studies, although these have focussed on the more southerly part of its range. A substantial number of new samples, many of them from the periphery of the species’ range, contribute to an exceptional dataset comprising 981 mitochondrial cytochrome b sequences. These new data provide sufficient resolution to transform our understanding of the survival of the species through the last glaciation and its subsequent re-colonization of the continent. The deepest genetic split that we found is in agreement with previous studies and runs from the Alps to central Ukraine, although we further distinguish two separate lineages in wood mice to the north and west of this line. It is likely that this part of Europe was colonized from two refugia, putatively located in the Iberian peninsula and the Dordogne or Carpathian region. The wood mouse therefore joins the growing number of species with extant populations that appear to have survived the Last Glacial Maximum in northern refugia, rather than solely in traditionally recognized refugial locations in the southern European peninsulas. Furthermore, the existence of a northern refugium for the species was predicted in a study of mitochondrial variation in a specific parasite of the wood mouse, demonstrating the potential value of data from parasites to phylogeographical studies. Lastly, the presence of related haplotypes in widely disparate locations, often on islands or separated by substantial bodies of water, demonstrates the propensity of the wood mouse for accidental human-mediated transport [less ▲]

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See detailA new long-tailed bsal bird from the Lower Cretaceous of north-eastern China
Lefevre, Ulysse ULiege; Hu, Dongyu; Escuillié, François et al

in Biological Journal of the Linnean Society (2014), 113(3), 790-804

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See detailEvidence of a complex phylogeographic structure in the common dormouse, Muscardinus avellanarius (Rodentia: Gliridae)
Mouton, Alice ULiege; Grill, Andrea; Sara, Maurizio et al

in Biological Journal of the Linnean Society (2012), 105(3), 648-664

This is the first mitochondrial phylogeography of the common dormouse, Muscardinus avellanarius (Linnaeus, 1758), a hibernating rodent strictly protected in Europe (Habitat Directive, annex IV; Bern ... [more ▼]

This is the first mitochondrial phylogeography of the common dormouse, Muscardinus avellanarius (Linnaeus, 1758), a hibernating rodent strictly protected in Europe (Habitat Directive, annex IV; Bern Convention, annex III). The 84 individuals of M. avellanarius, sampled throughout the distributional range of the species, have been sequenced at the mitochondrial DNA gene (cytochrome b, 704 base pairs). The results revealed two highly divergent lineages, with an ancient separation around 7.7 Mya and a genetic divergence of 7.7%. Lineage 1 occurs in Western Europe (France, Belgium, and Switzerland) and Italy, and lineage 2 occurs in Central–Northern Europe (Poland, Germany, Latvia, and Lithuania), on the Balkan Peninsula, and in Turkey. Furthermore, these two lineages are subdivided into five sublineages genetically isolated with a strong geographical association. Therefore, lineage 1 branches into two further sublineages (Western European and Italian), whereas lineage 2 contained three sublineages (Central–Northern European, Turkish, and Balkan). We observed low genetic diversity within the sublineages, in contrast to the significant level of genetic differentiation between them. The understanding of genetic population structure is essential for identifying units to be conserved. Therefore, these results may have important implications for M. avellanarius conservation. [less ▲]

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See detailMorphometric and genetic structure of the edible dormouse (Glis glis): A consequence of forest fragmentation in Turkey
Helvaci, Z.; Renaud, S.; Ledevin, R. et al

in Biological Journal of the Linnean Society (2012), 107(3), 611-623

Past climatic fluctuations influenced forest habitats and impacted heavily the distribution of forest species, such as the edible dormouse, by changing the distribution and composition of forests ... [more ▼]

Past climatic fluctuations influenced forest habitats and impacted heavily the distribution of forest species, such as the edible dormouse, by changing the distribution and composition of forests themselves. Such effects may be valid for ongoing climate change as well. To improve our understanding of the edible dormouse's history and how it responded to changes in its environment, we investigated its variation across the understudied zone of Northern Turkey using two complementary markers of differentiation: the mitochondrial cytochrome b gene for genetics, and size and shape of the first upper molar for phenotypic differences. Genetic and morphometric results were strongly discrepant. Genetic analyses evidenced an amazing homogeneity throughout the Eurasian range of the edible dormouse, whereas morphometrics pointed to a complex, step-wise differentiation along the Black Sea coast, the main signal being an opposition between Easternmost and Westernmost Turkish dormice. The genetic homogeneity suggests that this phenotypic differentiation is not the inheritance of glacial refuges, but the consequence of a more recent post-glacial isolation. The transition between the European and Asian groups is located eastwards from the Marmara straits, undermining its claimed role as an efficient barrier but stressing the importance of climatic and vegetational factors. A secondary differentiation between populations from the Central Black Sea coast and Easternmost regions was evidenced, attributed to a complex interplay of climatic, topographic, anthropogenic, and ecological factors. Turkey, at the crossroad of European and Asian species, heavily impacted by the current global change including climatic and anthropogenic factors, appears of importance for understanding the historical dynamics of differentiation and exchanges between populations that shaped the current distribution of Eurasian species and their future survival. © 2012 The Linnean Society of London. [less ▲]

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See detailDiscongruence of Mhc and cytochrome b phylogeographical patterns in Myodes glareolus (Rodentia: Cricetidae)
Malé, P.-J. G.; Martin, J.-F.; Galan, M. et al

in Biological Journal of the Linnean Society (2012), 105(4), 881-899

In the present study, a phylogeographical approach was developed to analyse the influence of selection and history on a major histocompatibility complex (Mhc) class II gene polymorphism in European bank ... [more ▼]

In the present study, a phylogeographical approach was developed to analyse the influence of selection and history on a major histocompatibility complex (Mhc) class II gene polymorphism in European bank vole (Myodes glareolus) populations. We focused on exon 2 of the Dqa gene because it is highly variable in a large array of species and appears to evolve under pathogen-mediated selection in several rodent species. Using single-strand conformation polymorphism analysis and sequencing techniques, 17 Dqa-exon2 alleles, belonging to at least two different copies of Dqa gene, were detected over the distribution range of M.glareolus. Evidence of selection was found using molecular and population analyses. At the molecular level, we detected 13 codons evolving under positive selection pressures, most of them corresponding to regions coding for putative antigen binding sites of the protein. At the European level, we compared patterns of population structure for the Dqa-exon2 and cytochrome b (cyt b) gene. We did not detect any spatial genetic structure among M.glareolus populations for the Dqa-exon2. These results strongly differed from those obtained using the cyt b gene, which indicated a recent phylogeographical history closely linked to the last glacial events. Seven mitochondrial lineages have yet been described, which correspond to major glacial refugia. Altogether, our results revealed clear evidence of balancing selection acting on Dqa-exon2 and maintaining polymorphism over large geographical areas despite M.glareolus history. It is thus likely that Mhc phylogeographical variability could have been shaped by local adaptation to pathogens. © 2012 The Linnean Society of London. [less ▲]

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See detailPatterns of morphological evolution of the cephalic region in damselfishes (Perciformes: Pomacentridae) of the Eastern Pacific
Aguilar-Medrano, Rosalia; Frederich, Bruno ULiege; De Luna, Efrain et al

in Biological Journal of the Linnean Society (2011), 102

Pomacentridae are one of the most abundant fish families inhabiting reefs of tropical and temperate regions. This family, comprising 29 genera, shows a remarkable diversity of habitat preferences, feeding ... [more ▼]

Pomacentridae are one of the most abundant fish families inhabiting reefs of tropical and temperate regions. This family, comprising 29 genera, shows a remarkable diversity of habitat preferences, feeding, and behaviours. Twenty-four species belonging to seven genera have been reported in the Eastern Pacific region. The present study focuses on the relationship between the diet and the cephalic profile in the 24 endemic damselfishes of this region. Feeding habits were determined by means of underwater observations and the gathering of bibliographic data. Variations in cephalic profile were analyzed by means of geometric morphometrics and phylogenetic methods. The present study shows that the 24 species can be grouped into three main trophic guilds: zooplanktivores, algivores, and an intermediate group feeding on small pelagic and benthic preys. Shape variations were low within each genus except for Abudefduf. Phylogenetically adjusted regression reveals that head shape can be explained by differences in feeding habits. The morphometric phylogeny recovered the subfamily Stegastinae and the relationship between Abudefduf troschelii and Chromis species. The cephalic profile of damselfishes contains a clear and strong phylogenetic signal. [less ▲]

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See detailEvolution of ontogenetic allometry shaping giant species: a case study from the damselfish genus Dascyllus (Pomacentridae)
Frederich, Bruno ULiege; Sheets, David

in Biological Journal of the Linnean Society (2010), 99(1), 99-117

The evolution of body size, the paired phenomena of giantism and dwarfism, has long been studied by biologists and paleontologists. However, detailed investigations devoted to the study of the evolution ... [more ▼]

The evolution of body size, the paired phenomena of giantism and dwarfism, has long been studied by biologists and paleontologists. However, detailed investigations devoted to the study of the evolution of ontogenetic patterns shaping giant species are scarce. The damselfishes of the genus Dascyllus appear as an excellent model for such a study. Their well understood phylogeny reveals that large-bodied species have evolved in two different clades. Geometric morphometric methods were used to compare the ontogenetic trajectories of the neurocranium and the mandible in both small-bodied (Dascyllus aruanus and Dascyllus carneus; maximum size: 50–65 mm standard length) and giant (Dascyllus trimaculatus and Dascyllus flavicaudus; maximum size: 90–110 mm standard length) Dascyllus species. At their respective maximum body size, the neurocranium of the giant species is significantly shorter and have a higher supraoccipital crest relative to the small-bodied species, whereas mandible shape variation is more limited and is not related to the ‘giant’ trait. The hypothesis of ontogenetic scaling whereby the giant species evolved by extending the allometric trajectory of the small-bodied ones (i.e. hypermorphosis) is rejected. Instead, the allometric trajectories vary among species by lateral transpositions. The rate of shape changes and the type of lateral transposition also differ according to the skeletal unit among Dascyllus species. Differences seen between the two giant species in the present study demonstrate that giant species may appear by varied alterations of the ancestor allometric pattern. [less ▲]

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See detailComparative phylogeography of four Apodemus species (Mammalia: Rodentia) in the Asian Far East: evidence of Quaternary climatic changes in their genetic structure
Sakka, H.; QUÉRÉ, J. P.; Kartavtseva, I. et al

in Biological Journal of the Linnean Society (2010), 100(4), 797-821

The phylogeography of four Apodemus species (Apodemus agrarius, Apodemus peninsulae, Apodemus latronum, and Apodemus draco) was studied in the Far East of Asia, based on sequences of the mitochondrial DNA ... [more ▼]

The phylogeography of four Apodemus species (Apodemus agrarius, Apodemus peninsulae, Apodemus latronum, and Apodemus draco) was studied in the Far East of Asia, based on sequences of the mitochondrial DNA cytochrome b gene. The results obtained show the existence of many different genetic lineages within the studied Apodemus species, suggesting the isolation and differentiation of populations in multiple refuge areas. Higher genetic diversities in some regions such as Yunnan, Sichuan (China), and eastern Russia suggest these areas are potential refuges for these species. The existence of such complex genetic structures could be linked to the presence of many biogeographic barriers (Himalaya Mountains, Tien-shan Mountains, Altai Mountains, Tibetan Plateau, Gobi desert, Yunnan Guizhou Plateau, Dzungaria basin, and others) in these regions, which were probably reinforced during the Quaternary climate changes. These barriers also played an important role concerning the low dispersal abilities of the two studied Apodemus species adapted to forest habitats (A. latronum and A. draco) with respect to colonizing regions other than China. © 2010 The Linnean Society of London. [less ▲]

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See detailEvolutionary history of the bank vole Myodes glareolus: a morphometric perspective
Ledevin, Ronan; Michaux, Johan ULiege; Deffontaine, Valerie et al

in Biological Journal of the Linnean Society (2010), 100(3), 681-694

The bank vole experienced a complex history during the Quaternary. Repeated isolation in glacial refugia led to the differentiation of several lineages in less than 300 000 years. We investigated if such ... [more ▼]

The bank vole experienced a complex history during the Quaternary. Repeated isolation in glacial refugia led to the differentiation of several lineages in less than 300 000 years. We investigated if such a recent differentiation led to a significant divergence of phenotypic characters between European lineages, which might provide insight into processes of intraspecific differentiation. The size and shape of the first and third upper molars, and first lower molar, of bank voles genetically attributed to different lineages were quantified using an outline analysis of their occlusal surface. The three teeth present similar trends of decreasing size towards high latitudes. This trend, the inverse of Bergmann's rule, is interpreted as the result of a balance between metabolic efficiency and food availability, favouring small body size in cold regions. Molar shape appeared to differ between lineages despite genetic evidence of suture zones. A mosaic pattern of evolution between the different teeth was evidenced. The analysis of such phenotypic features appears as a valuable complement to genetic analyses, providing a complementary insight into evolutionary processes, such as selective pressures, that have driven the differentiation of the lineages. It may further allow the integration of the paleontological dimension of the bank vole phylogeographic history. (C) 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 681-694. [less ▲]

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See detailSound production in four damselfish (Dascyllus) species: phyletic relationships?
Parmentier, Eric ULiege; Lecchini, David; Frederich, Bruno ULiege et al

in Biological Journal of the Linnean Society (2009), 97

Most studies of fish sounds show that the sounds are species-specific, with unique spectral and timing characteristics. This raises the question as to whether these sounds can be used to understand ... [more ▼]

Most studies of fish sounds show that the sounds are species-specific, with unique spectral and timing characteristics. This raises the question as to whether these sounds can be used to understand phyletic relationships between species and which acoustic parameters are subject to variation between species. In the present study, 597 sounds (and 2540 pulses) related to signal jumps of four Dascyllus species (Dascyllus aruanus, Dascyllus trimaculatus, Dascyllus albisella, and Dascyllus flavicaudus) from different geographic regions (Madagascar, Moorea, Rangiroa, and Hawaii) were analysed. It was possible to discern species-specific sounds, but also variation in sounds between populations. Large variations in sound length were found between Dascyllus species, whereas differences in interpulse duration were found to be variable between populations. In the regions where species live in sympatry, it appears that they restrict the variability in their sounds. This could comprise evidence of adaptation with character displacement of sonic characteristics where different species co-occur. However, sonic characteristics still overlapped substantially between species, suggesting that females would need to sample more than one sound and potentially use other cues to discriminate between species. [less ▲]

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See detailOntogenetic shape changes in Pomacentridae (Teleostei, Perciformes) and their relationships with feeding strategies: a geometric morphometric approach
Frederich, Bruno ULiege; Adriaens, Dominique; Vandewalle, Pierre ULiege

in Biological Journal of the Linnean Society (2008), 95

The present study explores the shape changes of cranial structures directly involved in food capturing during growth after reef settlement in two species of Pomacentridae (Dascyllus aruanus and ... [more ▼]

The present study explores the shape changes of cranial structures directly involved in food capturing during growth after reef settlement in two species of Pomacentridae (Dascyllus aruanus and Pomacentrus pavo). Landmark-based geometric morphometrics were used to study allometric patterns and related shape changes in four skeletal units: neurocranium, suspensorium and opercle, mandible and premaxilla. At settlement, the larvae of both species have a relatively similar morphology, especially with respect to the mandible. Their shapes suggest a feeding mode defined as ram/suction-feeding. Ontogenetic shape changes show a shift to a suction feeding mode of prey capture. The main transformations involved are an increase in height of the suspensorium and the opercle, an elevation of the supraoccipital crest, a relative shortening of the mandible, and a lengthening of the ascending process of the premaxilla. Shape changes of the mandible in the two studied species also reflect an increase of biting capacities. The high disparity between adult shape results from differences in the rate and in the length of ontogenetic trajectories, from divergence of the ontogenetic trajectories (neurocranium, mandible, and premaxilla) and parallel shifts of the trajectories in the size-shape space (suspensorium and opercle). In an evolutionary context, allometric heterochronies during ontogeny of different skeletal unit of the head may be considered as a basis for the explanation of the diversity of damselfishes. [less ▲]

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See detailTemporal shift of diet in alternative cannibalistic morphs of the tiger salamander
Denoël, Mathieu ULiege; Whiteman, Howard H.; Wissinger, Scott A.

in Biological Journal of the Linnean Society (2006), 89(2), 373-382

Evolutionary theory predicts that alternative trophic morphologies are adaptive because they allow a broad use of resources in heterogeneous environments. The development of a cannibal morphology is ... [more ▼]

Evolutionary theory predicts that alternative trophic morphologies are adaptive because they allow a broad use of resources in heterogeneous environments. The development of a cannibal morphology is expected to result in cannibalism and high individual fitness, but conflicting results show that the situation is more complex. The goal of the present study was to increase our understanding of the ultimate benefits of a cannibalistic polyphenism by determining temporal changes in the feeding habits and biomass intake in a population of tiger salamanders (Ambystoma tigrinum nebulosum). Cannibals in this species develop a larger head than typicals and have prominent teeth, both useful for consuming large prey. Although cannibalism was only detected in cannibal morphs, large temporal variation in resource partitioning was found between morphs. The two morphs always differed in their foraging habits, but cannibalism mainly occurred immediately after the ontogenetic divergence between morphs. Cannibals shifted their foraging later to a more planktivorous diet (i.e. the primarily prey of the typical morph). Cannibals also obtained more prey biomass than typicals. These results indicate that the cannibalistic morph is advantageous over the typical development, but that these advantages vary ontogenetically. Although the results obtained are consistent with models predicting the maintenance of cannibalism polyphenism in natural populations, they show that the foraging tactics utilized by cannibal morphs, and the fitness consequences accrued by such tactics, are likely to be more complex and dynamic than previous studies have suggested. (c) 2006 The Linnean Society of London. [less ▲]

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See detailTaxonomy, evolutionary history and biogeography of the broad-toothed field mouse (Apodemus mystacinus) in the eastern Mediterranean area based on mitochondrial and nuclear genes
Michaux, Johan ULiege; Bellinvia, E.; Lymberakis, P.

in Biological Journal of the Linnean Society (2005), 85(1), 53-63

The broad-toothed field mouse (Apodemus mystacinus) is distributed throughout the Balkan Peninsula, Asia Minor and the Middle East. It is generally split into two different specific entities: Apodemus ... [more ▼]

The broad-toothed field mouse (Apodemus mystacinus) is distributed throughout the Balkan Peninsula, Asia Minor and the Middle East. It is generally split into two different specific entities: Apodemus epimelas occurs on the Balkan Peninsula and A. mystacinus inhabits Asia Minor and the Middle East. This analysis, based on two mitochondrial regions (cytochrome b and the D-loop) and the interstitial retinol binding protein (IRBP) nuclear gene, confirms an important level of genetic divergence between the animals from these regions and their separation from each other at least 4.2-5.1 Mya, which is in favour of a distinct specific status. Finally, the broad-toothed field mice from southwestern Turkey appear to be closely related to the animals from Crete but highly distinct from the populations of the other Oriental regions. This supports a distinct subspecific level (A. m. rhodius) for the insular animals and also for those from south-western Turkey. From a biogeographical point of view, it can be assumed that either late Pliocene or early Pleistocene cooling led to the isolation of two main groups of A. mystacinus, one in the Balkan region and the other one in Turkey and the Near East (Syria and Israel). In this region, it is suggested that a more recent event appeared during the Quaternary period, isolating broad-toothed field mice in Crete and leading to the appearance of two well-differentiated genetic groups: one in Crete and south-western Turkey, and the other widespread in northern and eastern Turkey as well as in the Near East. © 2005 The Linnean Society of London. [less ▲]

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See detailGenetic variation and evolution in the genus Apodemus (Muridae : Rodentia)
Filippucci, M. G.; Macholan, M.; Michaux, Johan ULiege

in Biological Journal of the Linnean Society (2002), 75(3), 395-419

Genetic variation was studied using protein electrophoresis of 28-38 gene loci in 1347 specimens of Apodemus agrarius, A. peninsulac, A. flavicollis, A. sylvaticus, A. alpicola, A. uralensis, A. cf ... [more ▼]

Genetic variation was studied using protein electrophoresis of 28-38 gene loci in 1347 specimens of Apodemus agrarius, A. peninsulac, A. flavicollis, A. sylvaticus, A. alpicola, A. uralensis, A. cf. hyrcanicus, A. hermonensis, A. m. mystacinus and A. in. epimelas, representing 121 populations from Europe, the Middle East, and North Africa. Mean values of heterozygosity per locus for each species ranged from 0.02 to 0.04. Mean values of Nei's genetic distance (D) between the taxa ranged from 0.06 (between A. flavicollis and A. alpicola) to 1.34 (between A. uralensis and A. agrarius). The highest values of D were found between A. agrarius and other Apodemus species (0.62-1.34). These values correspond to those generally observed between genera in small mammals. Our data show that A. agrarius and A. peninsulae are sister species, well-differentiated from other taxa. High genetic distance between A. m. mystacinus and A. m. epimelas leads us to consider them distinct species and sister taxa to other Western Palaearctic species of the subgenus Sylvaemus. The data also suggest a recent separation of members of the latter group from a common ancestor, and subsequent rapid radiation, making it difficult to infer phylogenetic relationships. Some taxonomic implications of the results are discussed further. (C) 2002 The Linnean Society of London. [less ▲]

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