scholarly journals Global biogeography of Tetragnatha spiders reveals multiple colonization of the Caribbean

2018 ◽  
Author(s):  
Klemen Čandek ◽  
Ingi Agnarsson ◽  
Greta J. Binford ◽  
Matjaž Kuntner
Keyword(s):  
Dispersal Ability ◽  
Land Bridge ◽  
Biogeographic History ◽  
Putative Species ◽  
Dispersal Potential ◽  
The Caribbean ◽  
Low Levels ◽  
Richness Patterns ◽  
Globally Distributed ◽  
High Diversity

AbstractOrganismal variation in dispersal ability can directly affect levels of gene flow amongst populations, therefore importantly shaping species distributions and species richness patterns. The intermediate dispersal model of biogeography (IDM) predicts that in island systems, species diversity of those lineages with an intermediate dispersal potential is the highest. We broadly test this prediction, focusing on ‘four-jawed spiders’ (genus Tetragnatha) of the Caribbean archipelago. First, we report on original sampling of this globally distributed genus with numerous widespread as well as endemic species. We then reconstruct multiple Tetragnatha phylogenies from roughly 300 individuals delineated into 54 putative species. Our results support the monophyly of the four-jawed spiders but reject the monophyly of those lineages that reach the Caribbean, where we find low levels of endemism yet high diversity within Tetragnatha. The chronogram detects a potential early overwater colonization of the Caribbean, and in combination with reconstructed biogeographic history, refutes the possibility of ancient vicariant origins of Caribbean Tetragnatha as well as the GAARlandia land-bridge scenario. Instead, biogeographic results hypothesize multiple colonization events to, and from the Caribbean since mid-Eocene to late-Miocene. Tetragnatha seems unique among the arachnids explored so far in comprising some species that are excellent dispersers, and others that are not, perhaps having secondarily lost this dispersal propensity. A direct test of the IDM would require consideration of three categories of dispersers. However, four-jawed spiders do not fit one of these three a priori definitions, but rather represent a more complex combination of attributes of a ‘dynamic disperser’.

scholarly journals Biogeography of Long-Jawed Spiders Reveals Multiple Colonization of the Caribbean

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 622
Author(s):  
Klemen Čandek ◽  
Ingi Agnarsson ◽  
Greta J. Binford ◽  
Matjaž Kuntner
Keyword(s):  
A Priori ◽  
Dispersal Ability ◽  
Land Bridge ◽  
Biogeographic History ◽  
Putative Species ◽  
Evolutionary Changes ◽  
Dispersal Potential ◽  
The Caribbean ◽  
Richness Patterns ◽  
High Diversity

Dispersal ability can affect levels of gene flow thereby shaping species distributions and richness patterns. The intermediate dispersal model of biogeography (IDM) predicts that in island systems, species diversity of those lineages with an intermediate dispersal potential is the highest. Here, we tested this prediction on long-jawed spiders (Tetragnatha) of the Caribbean archipelago using phylogenies from a total of 318 individuals delineated into 54 putative species. Our results support a Tetragnatha monophyly (within our sampling) but reject the monophyly of the Caribbean lineages, where we found low endemism yet high diversity. The reconstructed biogeographic history detects a potential early overwater colonization of the Caribbean, refuting an ancient vicariant origin of the Caribbean Tetragnatha as well as the GAARlandia land-bridge scenario. Instead, the results imply multiple colonization events to and from the Caribbean from the mid-Eocene to late-Miocene. Among arachnids, Tetragnatha uniquely comprises both excellently and poorly dispersing species. A direct test of the IDM would require consideration of three categories of dispersers; however, long-jawed spiders do not fit one of these three a priori definitions, but rather represent a more complex combination of attributes. A taxon such as Tetragnatha, one that readily undergoes evolutionary changes in dispersal propensity, can be referred to as a ‘dynamic disperser’.

scholarly journals Caribbean golden orbweaving spiders maintain gene flow with North America

2018 ◽  
Author(s):  
Klemen Čandek ◽  
Ingi Agnarsson ◽  
Greta J. Binford ◽  
Matjaž Kuntner
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
North America ◽  
Population Genetic ◽  
Single Species ◽  
Haplotype Network ◽  
Dispersal Ability ◽  
Dispersal Potential ◽  
The Caribbean ◽  
Globally Distributed

AbstractThe Caribbean archipelago offers one of the best natural arenas for testing biogeographic hypotheses. The intermediate dispersal model of biogeography (IDM) predicts variation in species richness among lineages on islands to relate to their dispersal potential. To test this model, one would need background knowledge of dispersal potential of lineages, which has been problematic as evidenced by our prior biogeographic work on the Caribbean tetragnathid spiders. In order to investigate the biogeographic imprint of an excellent disperser, we study the American Trichonephila, a nephilid genus that contains globally distributed species known to overcome long, overwater distances. Our results reveal that the American T. clavipes shows a phylogenetic and population genetic structure consistent with a single species over the Caribbean, but not over the entire Americas. Haplotype network suggests that populations maintain lively gene flow between the Caribbean and North America. Combined with prior evidence from spider genera of different dispersal ability, these patterns coming from an excellent disperser (Trichonephila) that is species poor and of a relatively homogenous genetic structure, support the IDM predictions.

scholarly journals Genetic structure and biogeographic history of the Bicknell’s Thrush/ Gray-cheeked Thrush species complex

The Auk ◽  
2019 ◽  
Vol 137 (1) ◽  
Author(s):  
Alyssa M Fitzgerald ◽  
Jason Weir ◽  
Joel Ralston ◽  
Ian G Warkentin ◽  
Darroch M Whitaker ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Late Pleistocene ◽  
Species Complex ◽  
Extended Period ◽  
Genetic Data ◽  
Distribution Models ◽  
Biogeographic History ◽  
History Of ◽  
Low Levels ◽  
Bicknell's Thrush

Abstract We examined species limits, admixture, and genetic structure among populations in the Bicknell’s Thrush (Catharus bicknelli)–Gray-cheeked Thrush (C. minimus) species complex to establish the geographic and temporal context of speciation in this group, which is a model system in ecology and a high conservation priority. We obtained mitochondrial ND2 sequences from 186 Bicknell’s Thrushes, 77 Gray-cheeked Thrushes, and 55 individuals of their closest relative, the Veery (C. fuscescens), and genotyped a subset of individuals (n = 72) at 5,633 anonymous single nucleotide polymorphic (SNP) loci. Between-species sequence divergence was an order of magnitude greater than divergence within each species, divergence was dated to the late Pleistocene (420 kbp) based on Bayesian coalescence estimation, and a coalescent model (IMa) revealed almost no gene flow between species based on ND2. SNP data were consistent with mitochondrial results and revealed low levels of admixture among species (3 of 37 Bicknell’s Thrushes, no Gray-cheeked Thrushes, and no Veeries were >2% admixed). Species distribution models projected to the Last Glacial Maximum suggest that Bicknell’s Thrush and Gray-cheeked Thrush resided in primarily allopatric refugia in the late Pleistocene, consistent with the genetic data that support reproductive isolation over an extended period of time. Our genetic data suggest that both species underwent demographic expansions, possibly as they expanded out of Pleistocene refugia into their current ranges. We conclude that Bicknell’s Thrush and Gray-cheeked Thrush are 2 distinct species-level lineages despite low levels of Gray-cheeked Thrush introgression in Bicknell’s Thrushes, and divergence has been maintained by a long history of allopatry in subtly different habitats. Their unique phylogeography among boreal forest birds indicates that either cryptic species breaks in eastern North America are still undiscovered, or another factor, such as divergent natural selection, high migratory connectivity, or interspecific competition, played a role in their divergence.

The Biogeographic History of Iceland – The North Atlantic Land Bridge Revisited

2011 ◽  
pp. 647-668 ◽  
Author(s):  
Thomas Denk ◽  
Friðgeir Grímsson ◽  
Reinhard Zetter ◽  
Leifur A. Símonarson
Keyword(s):  
North Atlantic ◽  
Land Bridge ◽  
The North ◽  
Biogeographic History ◽  
History Of ◽  
The North Atlantic

scholarly journals Plastome Phylogenomic and Biogeographical Study on Thuja (Cupressaceae)

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Kole F. Adelalu ◽  
Xu Zhang ◽  
Xiaojian Qu ◽  
Jacob B. Landis ◽  
Jun Shen ◽  
...  
Keyword(s):  
North America ◽  
East Asia ◽  
Potential Effect ◽  
Molecular Dating ◽  
Disjunct Distribution ◽  
Land Bridge ◽  
Biogeographic History ◽  
Extant Species ◽  
History Of ◽  
Phylogenomic Analyses

Investigating the biogeographical disjunction of East Asian and North American flora is key to understanding the formation and dynamics of biodiversity in the Northern Hemisphere. The small Cupressaceae genus Thuja, comprising five species, exhibits a typical disjunct distribution in East Asia and North America. Owing to obscure relationships, the biogeographical history of the genus remains controversial. Here, complete plastomes were employed to investigate the plastome evolution, phylogenetic relationships, and biogeographic history of Thuja. All plastomes of Thuja share the same gene content arranged in the same order. The loss of an IR was evident in all Thuja plastomes, and the B-arrangement as previously recognized was detected. Phylogenomic analyses resolved two sister pairs, T. standishii-T. koraiensis and T. occidentalis-T. sutchuenensis, with T. plicata sister to T. occidentalis-T. sutchuenensis. Molecular dating and biogeographic results suggest the diversification of Thuja occurred in the Middle Miocene, and the ancestral area of extant species was located in northern East Asia. Incorporating the fossil record, we inferred that Thuja likely originated from the high-latitude areas of North America in the Paleocene with a second diversification center in northern East Asia. The current geographical distribution of Thuja was likely shaped by dispersal events attributed to the Bering Land Bridge in the Miocene and subsequent vicariance events accompanying climate cooling. The potential effect of extinction may have profound influence on the biogeographical history of Thuja.

scholarly journals Shell development, growth and sexual dimorphism in the Recent thecideide brachiopod Thecidellina meyeri sp. nov. from the Lesser Antilles, Caribbean

2009 ◽  
Vol 89 (3) ◽  
pp. 469-479 ◽  
Author(s):  
Jana Hoffmann ◽  
Carsten Lüter
Keyword(s):  
Morphological Characters ◽  
Lesser Antilles ◽  
Caribbean Region ◽  
Dispersal Ability ◽  
High Species Diversity ◽  
Limited Dispersal ◽  
Complete Series ◽  
The Caribbean ◽  
Insight Into ◽  
Material Study

A new thecideide brachiopod species, Thecidellina meyeri, is described from the southern Lesser Antilles (Aruba, Bonaire, Curaçao), Caribbean Sea, with unique morphological characters which clearly separate it from all other described species of Thecidellina in the region. A virtually complete series of ontogenetic stages is recorded, providing insight into the plasticity of shell development during growth in thecideide brachiopods and offering a well-defined standard for comparison with fossil material. Study of the soft tissue suggests that T. meyeri is dioecious, which contradicts the idea of Thecidellina to be hermaphroditic. The limited distribution and the unexpectedly high species diversity within the genus Thecidellina in the Caribbean region support the idea of allopatric speciation due to limited dispersal ability.

scholarly journals An updated assessment of Symbiodinium that associate with common scleractinian corals from Moorea (French Polynesia) reveals high diversity among background symbionts and a novel finding of clade B.

2016 ◽  
Author(s):  
Héloïse Rouzé ◽  
Gaël J Lecellier ◽  
Denis Saulnier ◽  
Serge Planes ◽  
Yannick Gueguen ◽  
...  
Keyword(s):  
Coral Species ◽  
French Polynesia ◽  
Molecular Tools ◽  
Quantitative Real Time Pcr ◽  
Algal Symbionts ◽  
Clade B ◽  
Highly Sensitive ◽  
Low Levels ◽  
First Time ◽  
High Diversity

The adaptative bleaching hypothesis (ABH) states that depending on the symbiotic flexibility of coral hosts (i.e., the ability of corals to “switch” or “shuffle” their algal symbionts), coral bleaching can lead to a change in the composition of their associated Symbiodinium community, and, thus, contribute to the coral’s overall survival. In order to determine the flexibility of corals, molecular tools are required to provide accurate species delineations, and to detect low levels of coral-associated Symbiodinium. Here, we used highly sensitive quantitative (real-time) PCR (qPCR) technology to analyse five common coral species from Moorea (French Polynesia), previously screened using only traditional conventional molecular methods, to assess the presence of low-abundance (background) Symbiodinium. Similar to other studies, each coral species exhibited a strong specificity to a particular clade, irrespective of the environment. In addition, however, each of the five species harboured at least one additional Symbiodinium clade, among clades A-D, at background levels. Unexpectedly, and for the first time in French Polynesia, clade B was detected as a coral symbiont. These results increase the number of known coral-Symbiodinium associations from corals found in French Polynesia, and likely indicate an underestimation of the ability of the corals in this region to associate with and/or “shuffle” different Symbiodinium clades. Altogether our data suggest that corals from French Polynesia may manage a trade-off between optimizing symbioses with a specific Symbiodinium clade(s), and maintaining associations with particular background clades that may play a role in the ability of corals to respond to environmental change.

scholarly journals Evidence for Miocene overwater colonization in CaribbeanCyrtognathaspiders

2018 ◽  
Author(s):  
Klemen Čandek ◽  
Ingi Agnarsson ◽  
Greta Binford ◽  
Matjaž Kuntner
Keyword(s):  
Gene Flow ◽  
Evolutionary History ◽  
Species Level ◽  
The Other ◽  
Lesser Antilles ◽  
Biogeographic History ◽  
Island Endemics ◽  
Mtdna Phylogeny ◽  
The Caribbean

AbstractIsland systems provide excellent arenas to test evolutionary hypotheses pertaining to gene flow and diversification of dispersal-limited organisms. Here we focus on an orbweaver spider genusCyrtognatha(Tetragnathidae) from the Caribbean, with the aims to reconstruct its evolutionary history, describe its biogeographic history in the archipelago, and to estimate the timing and route of Caribbean colonization. Specifically, we test ifCyrtognathabiogeographic history is consistent with an ancient vicariant scenario (the GAARlandia landbridge hypothesis) or overwater dispersal. We reconstructed a species level phylogeny based on one mitochondrial (CO1) and one nuclear (28S) marker. We then used this topology to constrain a time-calibrated mtDNA phylogeny, for subsequent biogeographical analyses of over 100 originally sampledCyrtognathaindividuals. Our results suggest a monophyletic radiation of CaribbeanCyrtognatha, containing 11 to 14 species that are exclusively single island endemics. Our analyses refute vicariance and instead support an overwater colonization to the Caribbean in mid-Miocene. Having colonized Hispaniola first,Cyrtognathasubsequently dispersed to, and diversified on, the other islands of the Greater, and Lesser Antilles.

scholarly journals Phylogeography of the widespread Caribbean spiny orb weaver Gasteracantha cancriformis

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8976
Author(s):  
Lisa Chamberland ◽  
Fabian C. Salgado-Roa ◽  
Alma Basco ◽  
Amanda Crastz-Flores ◽  
Greta J. Binford ◽  
...  
Keyword(s):  
Gene Flow ◽  
New World ◽  
Target Genes ◽  
Isolation By Distance ◽  
Separate Species ◽  
Widespread Species ◽  
Island Populations ◽  
The Caribbean ◽  
Morphological Species ◽  
Globally Distributed

Background Modern molecular analyses are often inconsistent with pre-cladistic taxonomic hypotheses, frequently indicating higher richness than morphological taxonomy estimates. Among Caribbean spiders, widespread species are relatively few compared to the prevalence of single island endemics. The taxonomic hypothesis Gasteracantha cancriformis circumscribes a species with profuse variation in size, color and body form. Distributed throughout the Neotropics, G. cancriformis is the only morphological species of Gasteracantha in the New World in this globally distributed genus. Methods We inferred phylogenetic relationships across Neotropical populations of Gasteracantha using three target genes. Within the Caribbean, we estimated genetic diversity, population structure, and gene flow among island populations. Results Our findings revealed a single widespread species of Gasteracantha throughout the Caribbean, G. cancriformis, while suggesting two recently divergent mainland populations that may represent separate species, diverging linages, or geographically isolated demes. The concatenated and COI (Cytochrome c oxidase subunit 1) phylogeny supported a Caribbean clade nested within the New World. Genetic variability was high between island populations for our COI dataset; however, gene flow was also high, especially between large, adjacent islands. We found structured genetic and morphological variation within G. cancriformis island populations; however, this variation does not reflect genealogical relationships. Rather, isolation by distance and local morphological adaptation may explain the observed variation.

scholarly journals An Evaluation of the Therapeutic Nutrition Knowledge of Belizean Nurses

2021 ◽  
Vol 2 (1) ◽  
pp. 01-07
Author(s):  
Marcia Magnus
Keyword(s):  
Response Rate ◽  
Nutritional Knowledge ◽  
The West ◽  
Nutrition And Diabetes ◽  
West Region ◽  
Nutritional Guidance ◽  
The Mean ◽  
The Caribbean ◽  
Low Levels ◽  
Correct Response Rate

In Belize, patients rely on nurses for nutritional guidance on non-communicable diseases in the Caribbean. The objectives of this study were to quantify the therapeutic nutritional knowledge of 198 Belizean nurses using the Al-Shwaiyat questionnaire. The mean correct response rate for the therapeutic nutritional knowledge was suboptimal (53.30%±17.20). Nurses in the West region of the country had the highest mean knowledge scores on nutrition and diabetes 75.41±20.10, p=0.003; on nutrition and cardiovascular diseases 57.23±10.90, p=0.000; and in overall knowledge 62.34±9.76 p=0.000. Nurses without a diagnosis of diabetes had higher mean knowledge scores on a) nutrition and diabetes 63.86±26.07, p=0.001; b) nutrition and obesity questions 49.55±20.80, p=0.004; c) nutrition and cardiovascular disease 53.30±15.70, p=0.007 and d), overall mean 55.24±16.67, p=0.000. There is a need to address the low levels of knowledge of Belizean nurses.

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