Search results for "GEOM"

Functional assessment of morphological homoplasy in stem-gnathostomes

2021

Osteostraci and Galeaspida are stem-gnathostomes, occupying a key phylogenetic position for resolving the nature of the jawless ancestor from which jawed vertebrates evolved more than 400 million years ago. Both groups are characterized by the presence of rigid headshields that share a number of common morphological traits, in some cases hindering the resolution of their interrelationships and the exact nature of their affinities with jawed vertebrates. Here, we explore the morphological and functional diversity of osteostracan and galeaspid headshields using an innovative approach that combines geometric morphometrics and computational fluid dynamics, thereby constraining the underlying fa…

paco: implementing Procrustean Approach to Cophylogeny in R

2017

Summary The concordance of evolutionary histories and extant species interactions provides a useful metric for addressing questions of how the structure of ecological communities is influenced by macro-evolutionary processes. We introduce paco (v0.3.1), an R package to perform Procrustean Approach to Cophylogeny. This method assesses the phylogenetic congruence, or evolutionary dependence, of two groups of interacting species using both ecological interaction networks and their phylogenetic history. We demonstrate the functionality of paco through its application to empirical host-parasite and plant-pollinator communities. Although the package is intended to assess the phylogenetic congruen…

Exploring species-level taxonomy in the Cryptocephalus flavipes species complex (Coleoptera: Chrysomelidae)

2016

In insects, morphological species identification is often challenging. The discrimination of closely related species may be hampered when only subtle differences in phenotypic characters or a continuum in their variability are present. This is exemplified in the Cryptocephalus flavipes species complex (Coleoptera; Chrysomelidae) where, until now, the species have been discriminated only by the yellow pattern on frons, pronotum, and epipleurae. In the present study, the phylogeny of the C. flavipes species complex was resolved through a multi-locus sequence approach, and the inclusion in the group of the phenotypically similar Cryptocephalus quadripustulatus Gyllenhal, 1813 was evaluated. Su…

Can multiple-model mimicry explain warning signal polymorphism in the wood tiger moth, Arctia plantaginis (Lepidoptera: Erebidae)?

2018

Effects of predation pressure and resource use on morphological divergence in omnivorous prey fish

2013

Background. Body shape is one of the most variable traits of organisms and responds to a broad array of local selective forces. In freshwater fish, divergent body shapes within single species have been repeatedly observed along the littoral-pelagic axes of lakes, where the structural complexity of near shore habitats provides a more diverse set of resources compared to the open-water zones. It remains poorly understood whether similar resource-driven polymorphism occurs among lakes that vary in structural complexity and predation pressure, and whether this variation is heritable. Here, we analyzed body shape in four populations of omnivorous roach (Rutilus rutilus) inhabiting shallow lakes.…

De novo genome assembly of the land snail Candidula unifasciata (Mollusca: Gastropoda)

2021

Abstract Among all molluscs, land snails are a scientifically and economically interesting group comprising edible species, alien species and agricultural pests. Yet, despite their high diversity, the number of genome drafts publicly available is still scarce. Here, we present the draft genome assembly of the land snail Candidula unifasciata, a widely distributed species along central Europe, belonging to the Geomitridae family, a highly diversified taxon in the Western-Palearctic region. We performed whole genome sequencing, assembly and annotation of an adult specimen based on PacBio and Oxford Nanopore long read sequences as well as Illumina data. A genome draft of about 1.29 Gb was gene…

Studies on the genus Capparis L. (Capparaceae) in Lao PDR. V: A new species from limestones of the Luang Prabang Province

2020

A new species of Capparis L., C. lianosa Fici & Souvannakhoummane, is described and illustrated from limestones of the Muang Ngoi District, Luang Prabang Province, in northern Lao PDR. Th e new species, belonging to Capparis sect. Monostichocalyx Radlk., is related to C. zeylanica L., differing in several characters as the shorter stipular thorns, the leaves with apex acuminate, the shorter, glabrous or glabrescent gynophore and the flattened stigma.

Cross inhibition improves activity selection when switching incurs time costs

2015

Abstract We consider a behavioural model of an animal choosing between two activities, based on positive feedback, and examine the effect of introducing cross inhibition between the motivations for the two activities. While cross-inhibition has previously been included in models of decision making, the question of what benefit it may provide to an animal’s activity selection behaviour has not previously been studied. In neuroscience and in collective behaviour cross-inhibition, and other equivalent means of coupling evidence-accumulating pathways, have been shown to approximate statistically-optimal decision-making and to adaptively break deadlock, thereby improving decision performance. Sw…

Seasonal cycle of benthic denitrification and DNRA in the aphotic coastal zone, northern Baltic Sea

2020

Current knowledge on the seasonality of benthic nitrate reduction pathways in the aphotic, density stratified coastal zone of the Baltic Sea is largely based on data from muddy sediments, neglecting the potential contribution of sandy sediments. To gain a more comprehensive understanding of seasonality in this part of the Baltic Sea coast, we measured rates of benthic denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) monthly in the ice-free period of 2016 in both sandy and muddy aphotic sediments, northwestern Gulf of Finland. No anammox was observed. The seasonal cycle of denitrification in both sediment types was related to the hydrography-driven development …

Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi) caudal fin from palaeoecological data

2017

Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in no…