scholarly journals Taxonomic, ecological and morphological diversity of Ponto-Caspian gammaridean amphipods: a review

2021 ◽  
Author(s):  
Denis Copilaș-Ciocianu ◽  
Dmitry Sidorov
Keyword(s):  
Invasive Species ◽  
Adaptive Radiation ◽  
Body Shape ◽  
Morphological Diversity ◽  
Ecological Diversity ◽  
Radiation Model ◽  
Ecological Gradient ◽  
Taxonomic Research ◽  
Adaptive Radiations ◽  
Species Evolution

AbstractThanks to its dynamic geological history the Ponto-Caspian region harbors a unique and unusually adaptable fauna, notorious for its invasive species. Gammarid amphipods attained considerable diversity, becoming the world’s second most speciose ancient-lake amphipod radiation. Nonetheless, apart from a few invasive species, this group remains poorly studied. Herein, we review and quantify the taxonomic, morphological and ecological diversity, as well as phylogenetic context of Ponto-Caspian gammarids within the adaptive radiation framework. Published molecular phylogenies indicate that this radiation has a monophyletic mid-Miocene Paratethyan origin, and is nested within the morphologically-conserved Atlanto-Mediterranean genus Echinogammarus. We find extensive disparity in body shape, size, ornamentation and appendage length, along a broad ecological gradient from mountain springs to depths exceeding 500 m, on virtually all substrate types (including symbiosis). We propose four putative ecomorphs that appear convergent with distantly related oceanic and Baikal Lake taxa. Thus, the identified patterns support the adaptive radiation model, although extensive further research is needed. A checklist and provisional key to all known endemic species are provided to facilitate taxonomic research. Ponto-Caspian gammarids could be a potentially powerful model for studying adaptive radiations and invasive species evolution.

Selection on old variants drives adaptive radiation of Metrosideros across the Hawaiian Islands

2020 ◽  
Author(s):  
Jae Young Choi ◽  
Xiaoguang Dai ◽  
Julie Z. Peng ◽  
Priyesh Rughani ◽  
Scott Hickey ◽  
...  
Keyword(s):  
Adaptive Radiation ◽  
Recurrent Selection ◽  
Balancing Selection ◽  
Hawaiian Islands ◽  
Ecological Niches ◽  
Gene Pools ◽  
Ecological Diversity ◽  
Founder Populations ◽  
Adaptive Radiations ◽  
Remote Islands

AbstractSome of the most spectacular adaptive radiations begin with founder populations on remote islands. How genetically limited founder populations give rise to the striking phenotypic and ecological diversity characteristic of adaptive radiations is a paradox of evolutionary biology. We conducted an evolutionary genomic analysis of genus Metrosideros, a landscape-dominant, incipient adaptive radiation of woody plants that spans a striking range of phenotypes and environments across the Hawaiian Islands. Using nanopore-sequencing, we created a chromosome-level genome assembly for M. polymorpha var. incana and analyzed wholegenome sequences of 131 individuals from 11 taxa sampled across the islands. We found evidence of population structure that grouped taxa by island. Demographic modeling showed concordance between the divergence times of island-specific lineages and the geological formation of individual islands. Gene flow was also detected within and between island taxa, suggesting a complex reticulated evolutionary history. We investigated genomic regions with increased differentiation as these regions may harbor variants involved in local adaptation or reproductive isolation, thus forming the genomic basis of adaptive radiation. We discovered differentiation outliers have arisen from balancing selection on ancient divergent haplotypes that formed before the initial colonization of the archipelago. These regions experienced recurrent divergent selection as lineages colonized and diversified on new islands, and hybridization likely facilitated the transfer of these ancient variants between taxa. Balancing selection on multiple ancient haplotypes–or time-tested variants–may help to explain how lineages with limited gene pools can rapidly diversify to fill myriad ecological niches on remote islands.Significance statementSome of the most spectacular adaptive radiations of plants and animals occur on remote oceanic islands, yet such radiations are preceded by founding events that severely limit genetic variation. How genetically depauperate founder populations give rise to the spectacular phenotypic and ecological diversity characteristic of island adaptive radiations is not known. We generated novel genomic resources for Hawaiian Metrosideros––a hyper-variable incipient adaptive radiation of woody taxa—for insights into the paradox of remote island radiations. We found that Metrosideros colonized each island shortly after formation and diversified within islands through recurrent selection on ancient variations that predate the radiation. Recurring use of ancient variants may explain how genetically depauperate lineages can diversify to fill countless niches on remote islands.

scholarly journals Continental cichlid radiations: functional diversity reveals the role of changing ecological opportunity in the Neotropics

2016 ◽  
Vol 283 (1836) ◽  
pp. 20160556 ◽  
Author(s):  
Jessica Hilary Arbour ◽  
Hernán López-Fernández
Keyword(s):  
Central America ◽  
Adaptive Radiation ◽  
Morphological Diversity ◽  
Evolutionary Rates ◽  
Ecological Niches ◽  
Ecological Opportunity ◽  
Ecological Release ◽  
Adaptive Radiations ◽  
Lineage Diversification

Adaptive radiations have been hypothesized to contribute broadly to the diversity of organisms. Models of adaptive radiation predict that ecological opportunity and ecological release, the availability of empty ecological niches and the response by adapting lineages to occupy them, respectively, drive patterns of phenotypic and lineage diversification. Adaptive radiations driven by ‘ecological opportunity’ are well established in island systems; it is less clear if ecological opportunity influences continent-wide diversification. We use Neotropical cichlid fishes to test if variation in rates of functional evolution is consistent with changing ecological opportunity. Across a functional morphological axis associated with ram–suction feeding traits, evolutionary rates declined through time as lineages diversified in South America. Evolutionary rates of ram–suction functional morphology also appear to have accelerated as cichlids colonized Central America and encountered renewed opportunity. Our results suggest that ecological opportunity may play an important role in shaping patterns of morphological diversity of even broadly distributed lineages like Neotropical cichlids.

scholarly journals Black spicules from a new interstitial opheliid polychaete Thoracophelia minuta sp. nov. (Annelida: Opheliidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naoto Jimi ◽  
Shinta Fujimoto ◽  
Mami Takehara ◽  
Satoshi Imura
Keyword(s):  
Developmental Biology ◽  
Phylogenetic Analysis ◽  
New Species ◽  
Morphological Diversity ◽  
The Body ◽  
Evolutionary Significance ◽  
Research Subject ◽  
Ecological Diversity ◽  
Coelomic Cavity ◽  
Molecular Phylogenetic

AbstractThe phylum Annelida exhibits high morphological diversity coupled with its extensive ecological diversity, and the process of its evolution has been an attractive research subject for many researchers. Its representatives are also extensively studied in fields of ecology and developmental biology and important in many other biology related disciplines. The study of biomineralisation is one of them. Some annelid groups are well known to form calcified tubes but other forms of biomineralisation are also known. Herein, we report a new interstitial annelid species with black spicules, Thoracophelia minuta sp. nov., from Yoichi, Hokkaido, Japan. Spicules are minute calcium carbonate inclusions found across the body and in this new species, numerous black rod-like inclusions of calcium-rich composition are distributed in the coelomic cavity. The new species can be distinguished from other known species of the genus by these conspicuous spicules, shape of branchiae and body formula. Further, the new species’ body size is apparently smaller than its congeners. Based on our molecular phylogenetic analysis using 18S and 28S sequences, we discuss the evolutionary significance of the new species’ spicules and also the species' progenetic origin.

Larval morphology predicts geographical dispersal range of Eastern Pacific eels

2019 ◽  
Vol 128 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Katherine E Dale ◽  
M Timothy Tinker ◽  
Rita S Mehta
Keyword(s):  
Body Shape ◽  
Phylogenetic Signal ◽  
Morphological Diversity ◽  
Marine Species ◽  
Eastern Pacific ◽  
Geographical Range ◽  
Larval Body ◽  
Adult Morphology ◽  
Adult Habitat ◽  
Eggs And Larvae

Abstract The geographical range of many marine species is strongly influenced by the dispersal potential of propagules such as eggs and larvae. Here, we investigate morphological diversity and the effect of body shape on geographical range of leptocephali, the unique, laterally compressed larvae of eels (order Anguilliformes). We used phylogenetically informed analyses to examine the morphological variation of larvae for 17 Eastern Pacific eel species from three adult habitats. We also investigated whether morphological traits of leptocephali could predict larval latitudinal range, hypothesizing that body shape may influence passive dispersal via currents. We found that no two species shared the same multivariate growth trajectories, with the size and scaling of pectoral fin length and snout-to-anus length being particularly variable. Larvae with longer relative predorsal and snout-to-anus lengths at median sizes exhibited wider larval geographical ranges. Body aspect ratio and maximum body length at metamorphosis, two traits we hypothesized to be important for passive transport, were not significant predictors of maximal larval range. We discovered an increase in phylogenetic signal over larval development as eels approach metamorphosis, potentially due to similar selective pressures between related species (such as juvenile habitat or adult morphology). Lastly, we conclude that larval body shape is probably influenced by adult habitat and adult morphology.

scholarly journals Adaptive radiation and hybridization in Wallace's Dreamponds: evidence from sailfin silversides in the Malili Lakes of Sulawesi

2006 ◽  
Vol 273 (1598) ◽  
pp. 2209-2217 ◽  
Author(s):  
Fabian Herder ◽  
Arne W Nolte ◽  
Jobst Pfaender ◽  
Julia Schwarzer ◽  
Renny K Hadiaty ◽  
...  
Keyword(s):  
New Species ◽  
Adaptive Radiation ◽  
Introgressive Hybridization ◽  
Reticulate Evolution ◽  
Species Group ◽  
Potential Force ◽  
Major Interest ◽  
Key Factor ◽  
Adaptive Radiations ◽  
Malili Lakes

Adaptive radiations are extremely useful to understand factors driving speciation. A challenge in speciation research is to distinguish forces creating novelties and those relevant to divergence and adaptation. Recently, hybridization has regained major interest as a potential force leading to functional novelty and to the genesis of new species. Here, we show that introgressive hybridization is a prominent phenomenon in the radiation of sailfin silversides (Teleostei: Atheriniformes: Telmatherinidae) inhabiting the ancient Malili Lakes of Sulawesi, correlating conspicuously with patterns of increased diversity. We found the most diverse lacustrine species-group of the radiation to be heavily introgressed by genotypes originating from streams of the lake system, an effect that has masked the primary phylogenetic pattern of the flock. We conclude that hybridization could have acted as a key factor in the generation of the flock's spectacular diversity. To our knowledge, this is the first empirical evidence for massive reticulate evolution within a complex animal radiation.

scholarly journals Habitat partitioning, habits and convergence among coastal nektonic fish species from the São Sebastião Channel, southeastern Brazil

2010 ◽  
Vol 8 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Fernando Zaniolo Gibran
Keyword(s):  
Habitat Use ◽  
Fish Species ◽  
Body Shape ◽  
Scientific Literature ◽  
Morphological Diversity ◽  
The Body ◽  
Divergent Evolution ◽  
Southeastern Brazil ◽  
Ecological Performance ◽  
Intimate Link

Based on a fish survey and preliminary underwater observations, 17 "morphotypes" were identified that characterize the morphological diversity found within 27 nektonic fish species sampled at São Sebastião Channel. Such "morphotypes" were studied using an ecomorphological approach, with the intention to investigate similarities and differences in shape and habits. Underwater field observations were also performed, to verify if the lifestyle of these species, such as vertical occupation of the water column and the habitat use, are in accordance with their distribution in the morphospace. The results, complemented with data from scientific literature on the taxonomy and phylogenies of these species, allowed discussing some of the typical cases of convergent and divergent evolution. Some of the ecomorphological clusters had no phylogenetic support although this is probably due to the environmental conditions in which theirs members have evolved. The body shape and fins positions of a fish clearly influence its ecological performance and habitat use, corroborating the ecomorphological hypothesis on the intimate link between phenotype and ecology.

scholarly journals Origin, adaptive radiation and diversification of the Hawaiian lobeliads (Asterales: Campanulaceae)

2008 ◽  
Vol 276 (1656) ◽  
pp. 407-416 ◽  
Author(s):  
Thomas J Givnish ◽  
Kendra C Millam ◽  
Austin R Mast ◽  
Thomas B Paterson ◽  
Terra J Theim ◽  
...  
Keyword(s):  
Molecular Phylogeny ◽  
Tropical Forests ◽  
Adaptive Radiation ◽  
Growth Form ◽  
Oceanic Island ◽  
Tube Length ◽  
Tropical Plants ◽  
Limited Dispersal ◽  
Adaptive Radiations ◽  
Morphological Differences

The endemic Hawaiian lobeliads are exceptionally species rich and exhibit striking diversity in habitat, growth form, pollination biology and seed dispersal, but their origins and pattern of diversification remain shrouded in mystery. Up to five independent colonizations have been proposed based on morphological differences among extant taxa. We present a molecular phylogeny showing that the Hawaiian lobeliads are the product of one immigration event; that they are the largest plant clade on any single oceanic island or archipelago; that their ancestor arrived roughly 13 Myr ago; and that this ancestor was most likely woody, wind-dispersed, bird-pollinated, and adapted to open habitats at mid-elevations. Invasion of closed tropical forests is associated with evolution of fleshy fruits. Limited dispersal of such fruits in wet-forest understoreys appears to have accelerated speciation and led to a series of parallel adaptive radiations in Cyanea , with most species restricted to single islands. Consistency of Cyanea diversity across all tall islands except Hawai i suggests that diversification of Cyanea saturates in less than 1.5 Myr. Lobeliad diversity appears to reflect a hierarchical adaptive radiation in habitat, then elevation and flower-tube length, and provides important insights into the pattern and tempo of diversification in a species-rich clade of tropical plants.

High morphological diversity in remote island populations of the peat moss Sphagnum palustre: glacial refugium, adaptive radiation or just plasticity?

2014 ◽  
Vol 117 (2) ◽  
pp. 95 ◽  
Author(s):  
Hans K. Stenøien ◽  
Kristian Hassel ◽  
Rossana Segreto ◽  
Rosalina Gabriel ◽  
Eric F. Karlin ◽  
...  
Keyword(s):  
Adaptive Radiation ◽  
Morphological Diversity ◽  
Glacial Refugium ◽  
Peat Moss ◽  
Island Populations ◽  
Remote Island ◽  
Sphagnum Palustre

scholarly journals Cranial shape evolution in adaptive radiations of birds: comparative morphometrics of Darwin's finches and Hawaiian honeycreepers

2017 ◽  
Vol 372 (1713) ◽  
pp. 20150481 ◽  
Author(s):  
Masayoshi Tokita ◽  
Wataru Yano ◽  
Helen F. James ◽  
Arhat Abzhanov
Keyword(s):  
Adaptive Radiation ◽  
Molecular Mechanisms ◽  
Rapid Evolution ◽  
Oceanic Islands ◽  
Shape Variation ◽  
Skull Morphology ◽  
Darwin's Finches ◽  
Hawaiian Honeycreepers ◽  
Darwin’S Finches ◽  
Adaptive Radiations

Adaptive radiation is the rapid evolution of morphologically and ecologically diverse species from a single ancestor. The two classic examples of adaptive radiation are Darwin's finches and the Hawaiian honeycreepers, which evolved remarkable levels of adaptive cranial morphological variation. To gain new insights into the nature of their diversification, we performed comparative three-dimensional geometric morphometric analyses based on X-ray microcomputed tomography (µCT) scanning of dried cranial skeletons. We show that cranial shapes in both Hawaiian honeycreepers and Coerebinae (Darwin's finches and their close relatives) are much more diverse than in their respective outgroups, but Hawaiian honeycreepers as a group display the highest diversity and disparity of all other bird groups studied. We also report a significant contribution of allometry to skull shape variation, and distinct patterns of evolutionary change in skull morphology in the two lineages of songbirds that underwent adaptive radiation on oceanic islands. These findings help to better understand the nature of adaptive radiations in general and provide a foundation for future investigations on the developmental and molecular mechanisms underlying diversification of these morphologically distinguished groups of birds. This article is part of the themed issue ‘Evo-devo in the genomics era, and the origins of morphological diversity’.

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