Differences In Functional Morphology Research Articles

Relative Genetic Homogeneity within a Phenotypically Diverse group: The Case of Lake Tana Labeobarbus (Cyprinidae) Species Flock, Ethiopia.

The Lake Tana Labeobarbus species flock represents one of the world's most famous examples of lacustrine species radiations. Previous studies of this group have resulted in the description of at least 15 species based on their differences in functional morphology and definition of two clades (lacustrine and riverine spawning clades) based on life history traits. A total of 166 fish representing 14 Labeobarbus species were genotyped using 10 lineage-specific hexaploid microsatellite loci. Six of these loci were developed for this study based on DNA sequence contigs derived from a microsatellite-enriched genomic library of Labeobarbus intermedius from Lake Tana; the remaining four loci were obtained from a previous study. The genotypes of the 10 loci were analyzed to examine genetic diversity and population structure within Lake Tana Labeobarbus. Overall mean allelic richness (NA) was 17.6 alleles per locus and observed (Ho) and expected (He) heterozygosities were 0.84 ± 0.14 and 0.73 ± 0.09, respectively, across all Lake Tana Labeobarbus samples examined. Our analyses reveal that there is little genetic differentiation among species (FST = 0.020-0.099; only 10 of 91 species comparisons were significant), but moderate differentiation (FST = 0.11, p < 0.05) between lacustrine and riverine spawning populations. Relative to previous phylogenetic hypotheses, our phenetic analysis employing the R-based Analysis of Phylogenetics and Evolution (APE) program seems to perform marginally better in revealing lineages within Lake Tana Labeobarbus. Herein, our results are compared to a previous microsatellite-based study of the same populations.

Sex Differences in Functional Morphology of Embryonic Murine Coronary Arteries

Cardiovascular diseases (CVDs) show significant sex differences, which has been attributed to the cardioprotective effects of estrogen. However, recent studies unravel that the underlying mechanisms seem unlikely to be due to estrogen alone, such as sex differences in mortality of extremely preterm newborns. Thus, we seek biological sex differences in cardiovascular development. A newly-developed coronary arteriogram enabled us to visualize the morphology of the coronary artery in the murine heart at embryonic day 17.5 by injecting nano-particle ink at constant pressure.

3D Muscle Fiber Architecture of Avian Jaw Muscles and their Significance for Avian cranial functional morphology evolution

Birds evolved a diversity of head shapes, feeding behaviors and jaw muscles which drive the feeding apparatus. However, capturing the anatomical and functional diversity of these muscles remains challenging and we know little about how jaw muscles develop, function and evolve among lineages of the clade and this hampers our ability to understand skeletal tissue biology, joint function, and patterns of evolution in bird skulls. Here we use contrast imaging, 3D muscle fiber tracking and new data visualization methods to explore the morphology, architecture and functional significance of the jaw muscles of a sample of birds to highlight the potential of these approaches. First, we show differences in functional morphology of jaw muscles between a hatchling and adult Mallard duck (Anas platyrhynchos). Ducks show a marked change in adductor chamber shape during ontogeny including an elongated postorbital process, quadrate orbital process and retroarticular process along with a broad temporal fossa which likely track with changes in muscle function and cranial kinesis. Indeed, we found m. depressor mandibulae in baby and adult ducks shifts from a rostrocadual orientation to a more dorsoventral orientation that offers additional mechanical advantage to jaw opening and propalinal mandible movement as well as concomitant changes in the 3D resultant and pennation of other jaw muscle bellies. Second, we show differences between a long‐ and short‐faced, dabbling birds (mallard, green‐wing teal), long faced orthally‐biting bird (belted kingfisher) and a short‐faced, hard‐biting bird, the grey parrot (Psittacus erithacus). We expected position, architecture and biomechanics of homologous muscles to differ substantially between these avian species given their different behaviors and overall cranial morphology. Although some muscles showed marked differences in resultant and pennation, others, including protractor pterygoideus, the primary actuator of kinesis, were remarkably similar in morphology suggesting a mosaic of changes happening during avian evolution. Together, these new, 3D high fidelity anatomical data on jaw muscle functional morphology in birds will not only better illuminate ecomorphological evolution but also illustrate how other clades of birds and vertebrates adapt their muscle architecture to meet functional demands.

Differences in morphological growth trajectories between greenside darter Etheostoma blennioides populations from two distinct drainages.

The greenside darter Etheostoma blennioides is a small-bodied benthic stream fish that occurs in multiple drainages of the eastern USA. Previous studies have revealed some morphological differentiations among greensides from isolated drainage systems but growth relationships among functional morphological characteristics have not been examined within and between populations. Specifically, we tested for differences in functional morphology and allometric distinctions in morphological growth trajectories between greenside populations from two drainages, the Osage River and White River. Morphological differences between individuals of the two drainages included more dorso-ventrally compressed bodies, longer snouts and larger jaw features in White River darters. Furthermore, body depth, snout length and jaw width grow at significantly different trajectories in individuals of the two drainages. Individuals of the White River drainage (generally a higher gradient stream system) become comparatively more streamlined and develop proportionately larger feeding related traits during growth. These results suggest that individuals of both drainages share a similar morphology during early life but deviate during continued development and this may be partially due to environmentally induced plastic response. This study represents a novel approach for comparing morphological development among fish populations and presents environmental factors (e.g., stream gradient and elevation) that potentially influence functional characteristics.

Functional Morphology and Defensive Behavior in a Social Aphid.

Social aphids produce different morphs, which are genetically identical but morphologically different. Each morph performs a different duty in its community. Social aphids usually produce morphologically distinct soldiers to protect their colonies. The social aphid Pseudoregma bambucicola produces sterile first instar soldiers with specialized body parts and unique defensive behaviors, such as hind leg waving. By using this species as a research model, this study tested the assumption that the functional morphological basis of defensive behaviors of soldiers is related to specialized body parts. Field observations and a comprehensive morphometric analysis were carried out for natural populations. The results showed significant differences in functional morphology between soldiers, first instar nymphs, and adults. Elongated hind legs in soldiers are an important functional morphological basis for the deimatic behavior of hind leg waving, while sclerotized front legs and head horns are related to the function of directly attacking natural enemies. The size variation of different body parts among different morphs also indicates a cost–benefit trade-off in the evolution of the social aphid species.

Trophic interactions in a lowland river fish community invaded by European barbel Barbus barbus (Actinopterygii, Cyprinidae)

Following their invasion, non-indigenous fish can potentially exclude native fishes from their original niches through competition, or can partition in their resource use with native species to facilitate co-existence. Here, using stable isotope analysis, the trophic interactions of invasive European barbel Barbus barbus and other fishes were tested in an invaded river of relatively low fish species diversity and where no other Barbus species were present. Testing was over three distinct life stages: age 0 + (< 38 mm), juveniles (86–231 mm) and adults (> 386 mm). There were strong patterns of isotopic niche partitioning between the juvenile fishes, with some inter-specific niche differences also apparent in 0 + fishes. For adult B. barbus and chub Squalius cephalus, however, niche convergence was evident. Within the B. barbus population, the niches of the adult fish differed significantly from the 0+ and juvenile fish, indicating considerable dietary changes with development. These results suggested that niche partitioning at the most abundant life stages were facilitating the co-existence of invasive B. barbus with other fishes in the community, with this most likely driven by inter-specific differences in functional morphology and habitat use.

Dental functional morphology predicts the scaling of chewing rate in mammals

How food intake and mastication scale to satisfy the metabolic needs of mammals has been the subject of considerable scientific debate. Existing theory suggests that the negative allometric scaling of metabolic rate with body mass is compensated by a matching allometric scaling of the chewing rate. Why empirical studies have found that the scaling coefficients of the chewing rate seem to be systematically smaller than expected from theory remains unknown. Here we explain this imparity by decoupling the functional surface area of teeth from overall surface area. The functional surface area is relatively reduced in forms emphasizing linear edges (e.g., lophodont) compared with forms lacking linear structures (e.g., bunodont). In forms with reduced relative functional surface, the deficit in food processed per chew appears to be compensated for by increased chewing rate, such that the metabolic requirements are met. This compensation accounts for the apparent difference between theoretically predicted and observed scaling of chewing rates. We suggest that this reflects adaptive functional evolution to plant foods with different fracture properties and extend the theory to incorporate differences in functional morphology.

A new enigmatic hyolith from the Cambrian of West Gondwana and its bearing on the systematics of hyoliths

AbstractThe genus Aladraco nom. nov. is described and discussed, along with two species recognized from coeval strata of the lower traditional middle Cambrian, A. schloppensis (Wurm) from the Tannenknock Formation of the Franconian Forest region, Germany, and A. ougnatensis sp. nov. from the Jbel Wawrmast Formation of the eastern Anti‐Atlas, Morocco. Aladraco was formerly known as Oxyprymna Kiderlen, a preoccupied generic name requiring renaming of the genus. The genus bears morphological characters such as the size, shape and external ornamentation of the conch which clearly indicate a systematic position in the class Hyolitha. A number of characters, such as a tripartition into an axial chamber and lateral acuminate processes, and the course of the apertural margin, differ considerably from those seen in the two orders Hyolithida and Orthothecida, and appear to indicate distinct differences in functional morphology. However, similarities of the morphological characters with the known representatives of the Hyolithida suggest that the species are derived from this systematic group and should be dealt with as a hitherto unrecognized distinct suborder and family, introduced as Aladracina subord. nov. and Aladracidae fam. nov.

Investigating a link between bill morphology, foraging ecology and kleptoparasitic behaviour in the fork-tailed drongo

Fork-tailed drongos, Dicrurus adsimilis , are facultative kleptoparasites of many bird and mammal species. They use complex alarm call strategies, a combination of both true and false alarm calls, to procure food items from their hosts. The evolution of this interspecific interaction may have been catalysed by a selective benefit for drongos that were able to procure a wider diversity of food resources through kleptoparasitism . We tested the hypothesis that drongos, which principally hawk their prey from a perch, employ kleptoparasitism to exploit a terrestrial foraging niche for which they do not possess the appropriate morphological adaptations, as indicated by bill morphology. We analysed the bill characteristics of the terrestrially foraging pied babbler, Turdoides bicolor , a primary host for the fork-tailed drongo, and both drongo and pied babbler museum specimens to establish potential links between differences in functional morphology and foraging ecology. We also observed the foraging behaviour of babblers and drongos in the Kalahari Desert . Drongo bills were significantly shorter, thicker and less curved than those of pied babblers, and large energy-rich subterranean prey items, such as insect larvae , were not procured by drongos while self-foraging. Furthermore, drongos preferentially attempted to kleptoparasitize prey types that they did not capture while self-foraging. We suggest that the calorific and nutrient content of a larger and more diverse set of prey, particularly buried larvae, which drongos did not excavate on their own, establishes a selection pressure for kleptoparasitism and may have contributed to the complex behavioural interactions between drongos and their hosts. ► Fork-tailed drongos kleptoparasitize pied babblers. ► We analyse bill morphology and foraging differences between drongos and babblers. ► Drongos target excavated prey when kleptoparasitizing babblers. ► Drongos possess significantly shorter, thicker bills than babblers. ► Procuring subterranean prey may partially incentivize kleptoparasitic behaviour.

The gynostegium of Hoya spartioides (Apocynaceae – Asclepiadoideae): A striking case of incongruence between molecular and phenotypic evolution

In molecular phylogenies Hoya spartioides, formerly regarded as the only species in a separate genus Absolmsia, is nested in the genus Hoya. It appears as sister to H. curtisii within a larger clade including H. lacunosa, H. imbricata, and H. caudata. In contrast to this close molecular relationship the floral morphology of H. spartioides differs considerably not only from that of its sister, H. curtisii, but from all other species of Hoya investigated so far. Of special interest are the differences in functional morphology of the pollinating apparatus, which in spite of its high degree of synorganization has undergone considerable evolutionary change in H. spartioides. Some of the new traits are even unique within the subfamily Asclepiadoideae as a whole. The large phenotypic distance between H. spartioides and H. curtisii is not reflected in corresponding differences in the tested marker genes, which raises the question of how the flower of H. spartioides has evolved.

Systematics of the Pacific monkey‐faced bats (Chiroptera: Pteropodidae), with a new species of Pteralopex and a new Fijian genus

The fruit‐bat genus Pteralopex comprises the monkey‐faced bats, a group of six endangered species found only in old‐growth forests on certain islands in the south‐west Pacific (the Solomon Islands and Fiji). The taxonomy of the genus is reviewed in detail and updated accordingly. Two ‘cryptic’ biological species are shown to occur in sympatry on both Bougainville and Choiseul in the northern Solomon Islands (corresponding to Pteralopex anceps Andersen, 1909 and a previously undescribed species) and each is accordingly described and reviewed. A new genus (Mirimiri) is erected for the Fijian monkey‐faced bat (formerly Pteralopex acrodonta), which differs greatly both morphologically and genetically from species of Pteralopex in the Solomon Islands. Ecomorphological differences between sympatric Pteralopex species are briefly reviewed, including potential differences in functional morphology and feeding ecology. Geographic patterns of occurrence and future survey priorities for monkey‐faced bats are also discussed.

The Physiological Ecology of Planktonic Sarcodines with Applications to Paleoecology: Patterns in Space and Time1

ABSTRACT. Planktonic sarcodines, suspended in the water column, are conveniently grouped into three categories based on functional morphology: (1) gymnamoebae and their relatives, which lack major living or nonliving compartmentalizing barriers, (2) foraminifera, and testate amoebae enclosed by a test or shell with one or more major openings, but lacking extensive cytoplasmic compartmentalizing barriers, and (3) radiolaria, which exhibit distinct compartmentalization of the cytoplasm into functional zones. Differences in feeding strategies and trophic activity of members in the three groups reflect in part these differences in functional morphology. Members of all three groups form symbiotic associations with Monera and protists, including algae, thus partially offsetting interspecific trophic competition among species occupying the same water mass. Physiological and morphological adaptations supporting a symbiotic association are presented. C14‐labeling studies of endosymbiotic radiolarian species show a substantial contribution of carbon to the host. Rates of calcification (planktonic foraminfera) and silica deposition (radiolaria) are reported, based on morphometric analyses and isotopic labeling studies. Major distributional patterns in space and time for each of the three groups, and some ecological principles explaining these regularities, are presented as related to population growth dynamics, niche differentiation, water‐mass properties, and the role of symbionts in supporting highly diverse communities of species within the same locale in the water column.

Body size, prey handling efficiency and choice of diet in three coniferous forest tits (Paridae)

The main purpose of this study was to link morphological differences between great tit (Parus major), willow tit (P. montanus) and coal tit (P. ater) and their rate of energy acquisition and choice of diet in order to explore the potential for competitive relations between them more directly. Handling times were measured in the laboratory by presenting mealworms of different sizes to the birds. Great tits were more efficient in handling large prey than were the smaller-bodied willow- and coal tits; for small prey sizes the coal tit was the least efficient species. Using the ratio of prey mass to the handling time value, a utility function for each species was constructed. These results suggests a potential for a segregation of the species on the food axis. However, results from the prey choice experiment show that despite considerable differences in functional morphology between the three species they do not differ significantly in the range of prey size exploited. My results suggest that the alleged importance of prey size partitioning is not likely to play the major role for the coexistence of these coniferous forests tits.

Moulting in phacopid trilobites

ABSTRACTPhacopid trilobites, unlike most trilobites, lack functionally articulated libregenae. This distinction presumably dictated ecdysial strategies which were fundamentally different from those forms with sutured cephala. Phacops rana (Green) and Greenops boothi (Green) from the Middle Devonian Hamilton Group (New York) are preserved in circumstances which illustrate certain aspects of their moulting behaviour. Undisturbed exuviae display five different moult patterns; these suggest two basic modes of exuviation in phacopid trilobites (Body-upright and Body Inversion Moult Procedures).Certain Hamilton beds yield clusters of Phacops comprising complete and/or moulted remains. Complete trilobites in body clusters display varied orientations which, when considered in conjunction with exuvial patterns in moult clusters, suggest ecdysial procedures that involved body inversion and erratic tergal contractions (Body Inversion Moult Procedures). Ensembles where in thoracopygidia are upright and outstretched indicate hyperextension of the thorax and disarticulation of the cephalo-thoracic suture (Body-upright Moult Procedures). Phacops moult ensembles are characterised by inverted and tightly recurved thoracopygidia, whereas Greenops ensembles comprise outstretched, usually upright thoracopygidia with cephala that are frequently upright. Classic ‘Salterian’ patterns are uncommon in Phacops rana and have not been recognised in Greenops boothi. Variations in moult procedure are attributed to differences in functional morphology and substrate consistency.