Functional consequences of morphological differentiation between populations of the Cape Dwarf Chameleon (Bradypodion pumilum)

Variation in phenotype between species or populations of the same species living in different habitats is often explained in an adaptive context with local habitat differences driving selection on morphological traits relevant in a given ecological context. Previous studies have demonstrated significant differences in limb and tail morphology between populations of the Cape Dwarf Chameleon (Bradypodion pumilum) living in closed vs. open habitats. However, the adaptive nature of the observed differences remains unclear. Here, we quantify the structural habitat use in two different populations, test whether the random habitat differs between the two sites and whether or not chameleons select perches randomly. Next, we test whether morphology is correlated with structural habitat use and test for differences in performance between populations. Our results demonstrate that habitats are structurally different, that chameleons in the two populations use perches of different diameters and that, in one of the populations, chameleons select relatively wider perches than available at random. Performance traits (hand and tail grip performance and sprint speed) are correlated with morphology (hand size, tail length and tibia length) and differ between sexes and populations. Moreover, performance is dependent on dowel size. These results suggest that differences in performance between populations are indeed adaptive and indicate the existence of true ecomorphs in chameleons of the genus Bradypodion. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 692–700.     

Ecomorphological variation and sexual dimorphism in a recent radiation of dwarf chameleons (Bradypodion)

Natural selection tends to favour optimal phenotypes either through directional or stabilizing selection; however, phenotypic variation in natural populations is common and arises from a combination of biotic and abiotic interactions. In these instances, rare phenotypes may possess a fitness advantage over the more common phenotypes in particular environments, which can lead to adaptation and ecological speciation. A recently radiated clade of dwarf chameleons (Bradypodion) restricted to southern KwaZulu‐Natal Province, South Africa, is currently comprised of two species (Bradypodion melanocephalum and Bradypodion thamnobates), yet three other phenotypic forms exist, possibly indicating the clade is far more speciose. Very little genetic differentiation exists between these five phenotypic forms; however, all are allopatric in distribution, occupy different habitats and vary in overall size and coloration, which may indicate that these forms are adapting to their local environments and possibly undergoing ecological speciation. To test this, we collected morphometric and habitat data from each form and examined whether ecological relevant morphological differences exist between them that reflect their differential habitat use. Sexual dimorphism was detected in four of the five forms. Yet, the degree and number of dimorphic characters was different between them, with size‐adjusted male‐biased dimorphism being much more pronounced in B. thamnobates. Habitat differences also existed between sexes, with males occupying higher perches in more closed canopy (forested) habitats than females. Clear morphological distinctions were detected between four of the five forms, with the head explaining the vast majority of the variation. Chameleons occupying forested habitats tended to possess proportionally larger heads and feet but shorter limbs than those in open canopy habitats (i.e. grassland). These results show that this species complex of Bradypodion is morphologically variable for traits that are ecologically relevant for chameleons, and that the variation among the five phenotypic forms is associated with habitat type, suggesting that this species complex is in the early stages of ecological speciation. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 113–130.     

The relationship between cranial morphology,bite performance,diet and habitat in a radiation of dwarf chameleon (Bradypodion)

Many animals show unique morphological and behavioural adaptations to specific habitats. In particular, variation in cranial morphology is known to influence feeding performance, which in turn influences dietary habits and, ultimately, fitness. Dietary separation is an important means of partitioning ecological niches and avoiding inter‐ and intraspecific competition. Consequently, differences in dietary resources may help explain phenotypic divergence in closely‐related species occupying different habitats, as well as sexual dimorphism. We test this hypothesis on five phenotypic forms of a recent radiation of dwarf chameleons (Bradypodion) that vary extensively in habitat use and cranial morphology. By examining stomach contents, the dietary composition of each phenotypic form is compared to investigate potential differences in feeding strategies. Overall, chameleons in the present study exhibit considerable dietary overlap (at both inter‐ and intraspecific levels), indicating that diet is not a major driver of variation in cranial morphology within this radiation. However, the stomachs of closed‐canopy females were found to contain more prey items than male stomachs, possibly indicating that females require a greater caloric intake than their male counterparts.     

Genetic variation of Mimetes hirtus and Mimetes fimbriifolius (Proteaceae) – a comparative analysis of two closely related fynbos species

We investigated the influence of differing life history traits on the genetic structure of the related species Mimetes fimbriifolius and Mimetes hirtus (Proteaceae), which occur in the South African fynbos. Both species are bird‐pollinated and ant‐dispersed, but differ in rarity, longevity, ecological strategy and the fragmentation of their distribution area. We used AFLPs to study genetic variation within and between 21 populations of these two species across their distribution range. AFLP analysis revealed significantly higher genetic variation within populations of M. fimbriifolius than within M. hirtus. While M. fimbriifolius clearly lacked any significant genetic differentiation between populations, a distinct geographic pattern was observed for M. hirtus. Differentiation was, however, stronger at the regional (Φ_PT = 0.57) than at the local scale (Φ_PT = 0.08). Our results clearly indicate that even closely related species that share the same mode of pollination and seed dispersal can differ in their genetic structure, depending on the magnitude of fragmentation, longevity of individuals and ecological strategy.     

Geographic variation and plasticity of leaf shape and size in Begonia dregei and B. homonyma (Begoniaceae)

The distinction between Begonia dregei and B. homonyma has hitherto been based on differences in the shape and size of leaves. A large sample of field-collected leaves has been examined using quantitative methods to test the validity of this distinction. Comparisons of leaf shape, with and without the inclusion of size-related variables, revealed three groups with a small amount of overlap, two of which correspond to B. dregei and one to B. homonyma. Effects of environmental conditions on leaf shape and size were examined in plants from four populations grown at two light intensities and compared with field collections. Leaf size varied little with environment, while margin roughness varied with the different conditions and there was variation among populations in the magnitude and direction of responses. These results show that leaf shape and size can be used as valid discriminators of groups within this taxon. Resolution of the taxonomy of this group will require consideration of heterogeneity within each of the three groups based on leaf shape and size.     

A phylogenetic analysis of variation in reproductive mode within an Australian lizard (Saiphos equalis, Scincidae)

Saiphos equalis , a semi-fossorial scincid lizard from south-eastern Australia, is one of only three reptile species world-wide that are known to display geographic variation in reproductive mode. Uniquely, Saiphos equalis includes populations with three reproductive modes: oviparous with long (15-day) incubation periods; oviparous with short (5-day) incubation periods; and viviparous (0-day incubation periods). No Saiphos populations show 'normal' scincid oviparity (> 30-day incubation period). We used mitochondrial nucleotide sequences ( ND2 and cytochrome b ) to reconstruct relationships among populations from throughout the species' distribution in New South Wales, Australia. Under the phylogenetic species concept, phylogenetic analyses are consistent with the oviparous and viviparous populations of S. equalis being conspecific. Phylogenetic analyses suggest that the long incubation period oviparous lineage is the sister group to all other populations; and that the viviparous populations belong to a cluster of weakly supported clades basal to the short-incubation-period oviparous clade. These clades correspond to variation in reproductive mode and geographic location.     

Waterbird assemblages and associated habitat characteristics of farm ponds in the Western Cape, South Africa

Natural freshwater wetlands are among the most threatened habitats on Earth. Effective wetland biodiversity conservation can not, however, be evaluated without fully understanding the roles of artificial waterbodies as refuges for water-dependent plants and animals. Waterbird assemblages were examined on 59 farm ponds in the Elgin and Caledon districts of the Western Cape, South Africa. This study examines the relationship between waterbird use and habitat characteristics of farm ponds. Patterns of temporal and spatial variation of waterbird species richness and abundance were quantified in relation to the habitat characteristics of each pond. Cluster analysis and multiple regression analyses identified surface area of the farm ponds as an important variable determining the presence and abundance of many waterbird species. Structural diversity in terms of vegetation in and around the ponds was especially important in determining their usage by waterbirds. These variables were evaluated in terms of creating a mosaic of habitat types (by varying vegetation structure and pond topography), which may be a useful way to enhance waterbird diversity at farm ponds. This study concludes that the high number of farm ponds in the transformed habitat matrix of the Western Cape plays an important role in conserving waterbirds.     

Morphological variation in vanishing Mexican desert fishes of the genus Characodon (Goodeidae)

This study investigated a rapidly vanishing group of fishes in the genus Characodon (including Characodon lateralis and Characodon audax) from the upper Rio Mezquital drainage in Mexico. Using specimens from museum collections, morphological variation was assessed to quantify body shape differentiation among historic (i.e. extirpated and extant) collection sites. In both sexes, body shape (particularly head shape, the proportion of the caudal peduncle and the position and size of dorsal and anal fins) varied significantly among populations and species. Variation among collection sites could at least partially be attributed to geography, as the presence of distinct hydrographic units and a major waterfall coincided with major body shape differences. These results are discussed in the light of previously published molecular genetic analyses, as they have direct implications for taxonomic problems and the need for conservation measures for these endangered fishes.     

Pentaschistis (Poaceae) diversity in the Cape mediterranean region: habitat heterogeneity and climate stability

Aim To evaluate the role of habitat heterogeneity on species richness and turnover in the mega species‐rich Cape Floristic Region (Cape), the mediterranean region of southern Africa. Location The Cape and Drakensberg regions of southern Africa. Methods Bioclimatic data were used to estimate habitat amount and habitat heterogeneity in the Cape and Drakensberg regions; these data were then used to explain the patterns of species diversity in the Pentaschistis clade (Poaceae) in these two regions. Habitat variables were used to create ‘bioclimatic units’ to characterize 1′× 1′ cells in southern Africa and to describe the niches of species. Using these bioclimatic units, the niche and range sizes of species in the two regions were compared. A phylogram was used to test for age and lineage effects. Results Pentaschistis species diversity and turnover are higher in the Cape than the Drakensberg. There is no significant difference in the habitat amount and heterogeneity between the two regions. Species occupy the same range of estimated niche sizes, yet there are significantly more range‐restricted Pentaschistis species in the Cape. Main conclusions The roles of age‐ and lineage‐related effects are rejected; biodiversity differences lie in the regions. Current macrohabitat does not explain the differences in biodiversity between the two regions. The larger number of range‐restricted species in the Cape cannot be explained by dispersal mechanism or the occupation of range‐restricted habitats. Species of Pentaschistis and other Cape clades share characteristics associated with species from historically climatically stable areas, and palaeoclimatic and palaeontological evidence indicates the Cape climate has been more stable than the Drakensberg climate throughout the Pleistocene. We conclude that the corresponding lack of extinction might have allowed an accumulation of species in the Cape. Similar climatic and biological evidence for the south‐west Australian Floristic and Mediterranean regions indicate that the same mechanism might explain the high species richness of these mediterranean regions.     

Insights into the habitat of Middle Permian pareiasaurs (Parareptilia) from preliminary isotopic analyses

Pareiasaurs were an abundant group of large herbivores during Middle and Late Permian times. The habitat of pareiasaurs has proven enigmatic, and ecological interpretations from anatomical and taphonomic data have included aquatic, semi‐aquatic to fully terrestrial lifestyles. Insight into the ecology of extinct taxa can also be gained from stable isotope analyses, and interpretations benefit from studies of multiple, coeval groups. Here, we report the first stable carbon and oxygen isotope analyses from the enamel, dentine and bone of pareiasaurs and contemporaneous therapsids (dinocephalians and therocephalians), in specimens recovered from the Permian Tapinocephalus to lower Pristerognathus Assemblage Zones of South Africa. Previous ecological inferences for dinocephalians (riparian to terrestrial) and therocephalians (terrestrial) are less ambiguous than reconstructions for pareiasaurs and provide an independent reference for interpreting stable isotope measurements. Oxygen isotopes of enamel carbonate were indistinguishable between pareiasaurs and therocephalians, which had higher values than dinocephalians. The data suggest that dinocephalians and pareiasaurs (megaherbivores) inhabited different ecological niches and that pareiasaurs may have shared a terrestrial habitat with therocephalians (carnivores). Our results agree with earlier suggestions of a terrestrial lifestyle among pareiasaurs and provide evidence of niche partitioning among large coeval Capitanian herbivores of South Africa.     

Morphological variation of the five vole species of the genus Microtus (Mammalia,Rodentia, Arvicolinae) occurring in Greece

Morphometric data for the five vole species of the genus Microtus living in Greece are old, sparse, poor and insufficiently analysed. This work aims to give the first comprehensive morphometric analysis of body and skull inter‐ and intraspecific variation for M. (M.) guentheri, M. (M.) rossiaemeridionalis, M. (Terricola) subterraneus, M. (T.) felteni and M. (T.) thomasi, applying multivariate statistics to 28 linear morphometric variables. It was based on ample material (202 adult individuals) using samples from localities that adequately cover the entire distributional range of each species in Greece. The five species and the two subgenera (Microtus and Terricola) were morphometrically clearly distinguished and discriminating variables were revealed. However, morphometrics did not provide robust criteria to infer phylogenetic relations among species. Furthermore, three species, M. (M.) guentheri, M. (M.) rossiaemeridionalis and M. (T.) thomasi, exhibited considerable intraspecific size or shape variation, which was mostly random and not associated with geographical proximity. Comparisons with data in the literature, mainly concerning populations of these species from adjacent areas, indicate that the Greek M. (M.) guentheri, M. (M.) rossiaemeridionalis and M. (T.) thomasi tend to be smaller than their conspecifics, while M. (T.) subterraneus and M. (T.) felteni are about equal in size to their Balkan relatives.     

Morphological variation among the inner ears of extinct and extant baleen whales (Cetacea: Mysticeti)

Living mysticetes (baleen whales) and odontocetes (toothed whales) differ significantly in auditory function in that toothed whales are sensitive to high‐frequency and ultrasonic sound vibrations and mysticetes to low‐frequency and infrasonic noises. Our knowledge of the evolution and phylogeny of cetaceans, and mysticetes in particular, is at a point at which we can explore morphological and physiological changes within the baleen whale inner ear. Traditional comparative anatomy and landmark‐based 3D‐geometric morphometric analyses were performed to investigate the anatomical diversity of the inner ears of extinct and extant mysticetes in comparison with other cetaceans. Principal component analyses (PCAs) show that the cochlear morphospace of odontocetes is tangential to that of mysticetes, but odontocetes are completely separated from mysticetes when semicircular canal landmarks are combined with the cochlear data. The cochlea of the archaeocete Zygorhiza kochii and early diverging extinct mysticetes plot within the morphospace of crown mysticetes, suggesting that mysticetes possess ancestral cochlear morphology and physiology. The PCA results indicate variation among mysticete species, although no major patterns are recovered to suggest separate hearing or locomotor regimes. Phylogenetic signal was detected for several clades, including crown Cetacea and crown Mysticeti, with the most clades expressing phylogenetic signal in the semicircular canal dataset. Brownian motion could not be excluded as an explanation for the signal, except for analyses combining cochlea and semicircular canal datasets for Balaenopteridae. J. Morphol. 277:1599–1615, 2016. © 2016 Wiley Periodicals, Inc.     

Life history and population dynamics of an endangered seahorse (Hippocampus capensis) within an artificial habitat

Species-specific life-history information is critical for successful conservation, particularly in establishing an accurate baseline status. Obtaining such information is challenging for most species, but in particular for rare and threatened marine species. To facilitate future conservation of the endangered Knysna seahorse (Hippocampus capensis) this study aimed to determine important life-history information for this species. Visible implant fluorescent elastomer (VIFE) tags were used to mark 78 seahorses within a residential marina estate in the Knysna estuary, South Africa, in February 2018. Using a mark-resight approach, the size and movement patterns of the population and growth rate of seahorses were determined over a 14-month period. The closed population estimate for H. capensis, within Thesen Islands Marina, was estimated to be 134 (118–152 95% C.I. ) in February 2018 compared to only 72 (48–108 95% C.I. ) in February 2019. The species showed rapid initial growth with males and females having similar rates of growth based on the specialised von Bertalanffy growth function model. The importance of Reno mattresses as a habitat for H. capensis was confirmed based on the high abundance and site fidelity of the population, which emphasises the conservation potential of heavily modified environments for threatened seahorse species. The use of VIFE tags was deemed effective in studying this endangered seahorse and allowed the collection of important information for this species which can be used in future Red List assessments and conservation actions.     

Potential impact of viticulture expansion on habitat types in the Cape Floristic Region, South Africa

The wine industry in the Western Cape, South Africa has expanded over the past decade, particularly since the lifting of trade sanctions in 1992. Wine grapes are cultivated on fertile soils upon which threatened biodiversity habitat units of the Cape Floristic Region occur naturally. There is a concern as to whether further expansion of the wine industry, which would benefit the economy through increased foreign exchange, would encroach on the little remaining vegetation in vineyard-producing areas. Predictive land use modeling using logistic regression techniques was applied to determine suitable areas for vineyard cultivation according to climatic, topographic, and soil/geology variables. Of the most threatened habitats, 14849 hectares are particularly suitable for vineyards. Breede fynbos/renosterveld mosaic was the habitat most likely to be converted, and was considered 89.3% irreplaceable to current conservation goals. Also vulnerable are Ashton inland renosterveld and Boland coast renosterveld, the latter being 100% irreplaceable. Although the high rate in vine replanting suggests that the need for untransformed land will not be great immediately, an economic analysis showed that protection of these areas against future ploughing will be vital if targets of adequately representing each habitat in the Cape Floristic Region are to be met. Land use change modeling, especially if done in a spatially explicit and integrated manner with expert input, was shown to be an important technique for the extrapolation of historical patterns to understand the forces that shape landscapes, allowing for the assessment of management alternatives, and testing our understanding of key processes in land use changes that effect conservation planning.     

A multivariate analysis of the fringe-toed lizards of the Acanthodactylus scutellatus group (Squamata: Lacertidae): systematic and biogeographical implications

The taxonomy of the fringe-toed lizards of the Acanthodactylus scutellatus group has long been unstable and no consensus exists on the systematic status of its various forms. A multivariate analysis of morphological characters, performed on over 1000 specimens from most of the African range of this group, allowed us to clarify the specific allocation of most of the Saharan populations included in this species group. Based on comparisons of morphology between allopatric and sympatric populations of this complex, we propose the recognition of six biological species. Our results confirm the specific status of Acanthodactylus aureus , A. dumerili , A. scutellatus, A. longipes and the recently described A. taghitensis . In addition, we re-validate A. senegalensis (occurring from Mauritania and Mali south to Senegal), which has been treated as a synonym of A. dumerili by previous authors. Acanthodactylus longipes is reported for the first time from coastal Mauritania, and A. taghitensis (previously known only from a very small region in Algeria) is reported from continental Mauritania. The systematic section of this paper includes a full list of examined material, diagnosis and known distribution of each species, in addition to some information on geographical variation and ecology. A key for specific identification is provided as an appendix.  © 2003 The Linnean Society of London, Zoological Journal of the Linnean Society, 2003, 137 , 117−155.     

Morphometric and genetic structure of the edible dormouse (Glis glis): a consequence of forest fragmentation in Turkey

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, Biological Journal of the Linnean Society, 2012, 107 , 611–623.