Informed management and conservation efforts are vital to sustainable recreational fishing and biodiversity conservation. Because the taxonomic rank of species is important in conservation and ...management strategies, success of these efforts depends on accurate species delimitation. The Black Basses (Micropterus) are an iconic lineage of freshwater fishes that include some of the world's most popular species for recreational fishing and world's most invasive species. Despite their popularity, previous studies to delimit species and lineages in Micropterus suffer from insufficient geographic coverage and uninformative molecular markers. Our phylogenomic analyses of ddRAD data result in the delimitation of 19 species of Micropterus, which includes 14 described species, the undescribed but well-known Altamaha, Bartram's, and Choctaw basses, and two additional undescribed species currently classified as Smallmouth Bass (M. dolomieu). We provide a revised delimitation of species in the Largemouth Bass complex that necessitates a change in scientific nomenclature: Micropterus salmoides is retained for the Florida Bass and Micropterus nigricans is elevated from synonymy for the Largemouth Bass. The new understanding of diversity, distribution, and systematics of Black Basses will serve as important basis for the management and conservation of this charismatic and economically important clade of fishes.
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•First multi-locus molecular phylogenetic investigation of Gobiesox.•Freshwater species of Gobiesox are monophyletic.•Pherallodiscus is placed in the synonymy of Gobiesox.•Two ...competing classifications for the Gobiesocidae contain non-monophyletic groups.
The phylogenetic relationships between marine and freshwater members of the New World clingfish genus Gobiesox are investigated using both mitochondrial and nuclear sequence data. Phylogenetic hypotheses are derived from Bayesian and maximum parsimony analyses of a six-gene concatenated data set (2 mitochondrial and 4 nuclear markers; 4098bp). Gobiesox is paraphyletic, due to the inclusion of Pherallodiscus, in phylogenetic hypotheses resulting from all analyses and its two included species are reassigned to Gobiesox. Within the expanded genus Gobiesox, the freshwater species (G. cephalus, G. juradoensis, G. mexicanus and G. potamius) represent a monophyletic group that is nested inside of a paraphyletic marine group. Based on the monophyly of the freshwater clingfishes, a habitat transition from marine to freshwater is inferred to have occurred only once in the evolutionary history of the group (potentially in the mid-Miocene). Gobiesox is obtained as part of a larger clade of New World clingfishes, including also members of Acyrtops, Acyrtus, Arcos, Rimicola, Sicyases and Tomicodon equivalent to the subfamily Gobiesocinae. The phylogenetic hypotheses obtained are discussed briefly in relation to the two alternative classifications currently in use simultaneously for the Gobiesocidae. A rediagnosis and list of included species is provided for Gobiesox.
Ban the trade of non-native species for consumption as food or derived products and for personal use (i.e., as pets).
- Ban the trade of native species when they do not originate from within the ...nation (i.e., same genetically defined conservation unit).
- Tracking of potential established alien
Rana
populations.
- Eradication of potentially established alien
Rana
populations.
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•Analysis of 16 nuclear genes result in unique phylogenetic hypotheses for the economically important North American freshwater fish lineage Centrarchidae.•Morphological datasets ...resolve the Eocene fossil †Plioplarchus whitei as a crown lineage Centrarchidae.•The rich fossil record is used to provide a comprehensive relaxed molecular clock analysis using tip dating and a fossilized birth–death branching model.•The new time calibrated phylogeny of Centrarchidae provides a valuable tool for the continued study of speciation and macroevolution in the clade.
Species of the North American freshwater fish lineage Centrarchidae are apex predators in their habitats and are among the world’s most popular sport fishes. Centrarchids boast a rich fossil record that extends from the latest Eocene to the Pleistocene. To investigate the phylogeny and timing of diversification of Centrarchidae, we deploy a dataset of DNA sequences of 16 nuclear genes sampled from nearly all of the recognized and undescribed species. We also utilize previously published morphological datasets to assess the phylogenetic placement of one of the oldest known centrarchid fossils, †Plioplarchus whitei. A Bayesian multispecies coalescent species tree analysis provides insight on relationships that evaded resolution in earlier studies, such as the relationships of Acantharchus pomotis, the resolution of a clade consisting of species previously synonymized under the Spotted Bass, Micropterus punctulatus, and a clade of recently described species previously considered populations of the Redeye Bass, Micropterus coosae. This new molecular phylogeny and the inclusion of †P. whitei and other centrarchid fossils in the tip-dated fossilized birth–death analysis results in a new hypothesis of the timing of diversification in Centrarchidae that contextualizes the ages of centrarchid fossils to the timing of speciation among the extant species. In addition to providing new temporal perspectives on the diversification of freshwater fishes in North America, this study may close of the chapter of centrarchid phylogeny inferred using Sanger-sequenced genes, as the use of genomic-scale datasets becomes mainstream in the phylogenetics of fishes.
Abstract
Introgression and hybridization are major impediments to genomic-based species delimitation because many implementations of the multispecies coalescent framework assume no gene flow among ...species. The sunfish genus Lepomis, one of the world’s most popular groups of freshwater sport fish, has a complicated taxonomic history. The results of ddRAD phylogenomic analyses do not provide support for the current taxonomy that recognizes two species, Lepomis megalotis and Lepomis peltastes, in the L. megalotis complex. Instead, evidence from phylogenomics and phenotype warrants recognizing six relatively ancient evolutionary lineages in the complex. The introgressed and hybridizing populations in the L. megalotis complex are localized and appear to be the result of secondary contact or rare hybridization events between nonsister species. Segregating admixed populations from our multispecies coalescent analyses identifies six species with moderate to high genealogical divergence, whereas including admixed populations drives all but one lineage below the species threshold of genealogical divergence. Segregation of admixed individuals also helps reveal phenotypic distinctiveness among the six species in morphological traits used by ichthyologists to discover and delimit species over the last two centuries. Our protocols allow for the identification and accommodation of hybridization and introgression in species delimitation. Genomic-based species delimitation validated with multiple lines of evidence provides a path towards the discovery of new biodiversity and resolving long-standing taxonomic problems.ddRAD; genealogical divergence index; hybridization; integrative species delimitation; phylogeny; secondary contact; systematics; taxonomy.
Abstract
A fundamental goal of evolutionary biology is to understand the mechanisms that generate and maintain biodiversity. Discovery and delimitation of species represent essential prerequisites ...for such investigations. We investigate a freshwater fish species complex comprising Etheostoma bellator and the endangered E. chermocki, which is endemic to the Black Warrior River system in Alabama, USA, a global hotspot of temperate freshwater biodiversity. Phylogenomic analyses delimit five geographically disjunct species masquerading as E. bellator. Three of these new species exhibit microendemic distributions comparable to that of E. chermocki raising the possibility that they also require protection. The species of the complex are found in streams flowing over carbonate rock and they are separated by waterways flowing over siliciclastic rock, a geographic pattern dictated by the underlying stratigraphy and structural geology. Over time, rivers have eroded downward through layers of siliciclastic rocks in the basin, gradually exposing underlying carbonate rock, the substrate of suitable habitat today. Our results suggest that episodic dispersal to patches of suitable habitat set the stage for allopatric speciation in the species complex. Our study suggests that the presence of heterogeneous rock can facilitate dispersal-mediated allopatric speciation in freshwater organisms in the absence of external tectonic or climatic perturbations.
Human-mediated introductions of non-native species are expected to increase globally and threaten native biodiversity.
Lepomis auritus
(Redbreast Sunfish), a carnivorous freshwater fish native to ...rivers in eastern North America, has been introduced far outside of its native range due to its popularity in recreational fisheries. However, poor documentation of introductions and lack of thorough ichthyofaunal surveys before the mid-20th century have complicated our understanding of the establishment and spread of non-native
L. auritus
over the past 90 years, precluding effective management. We conducted phylogenomic analyses using ddRAD data from 197 specimens of
L. auritus
collected throughout the known geographic range of the species to reconstruct the introduction history of the species. Our protocols allow for the reconstruction of complicated introduction routes and reveal that
L. auritus
in Texas is the result of a single-source introduction from the Suwannee River, the population in the upper Tennessee River has two sources of introduction from the Savannah River and the northeastern rivers that drain into the Atlantic Ocean, and the populations in the middle Tennessee River and the Mobile River Basin have sources from the upper Tennessee River system and the Apalachicola River Basin. Ecological and evolutionary investigations of the non-native populations of
L. auritus
will broaden the understanding of invasion dynamics in species of
Lepomis
and other non-native freshwater fishes in North America. Our study provides critical information for the conservation of native populations and invasive management of non-native populations of
L. auritus
.
The use of tablet during the office work is on the rise, but the biomechanical response of tablet use under various sitting postures is not well understood.
This study quantitatively measured changes ...in trunk kinematics under three sitting conditions (raised leg, neutral leg, and lowered leg) while using a tablet.
Fifteen participants were asked to sit on a chair with three different postures while staring at a handheld tablet or gazing straight ahead with a bare hand, and the head flexion, lumbar flexion and trunk inclination were captured with electrical goniometers.
The results revealed significantly less lumbar flexion (12.8%) and trunk inclination (28.0%) while using the tablet compared to the empty hand condition (p < 0.001), but at a significant cost of increased head flexion (90.8%; p < 0.001). Further, while using the tablet, participants showed less head flexion in the raised leg condition (p < 0.001) than in the others (9.7% and 7.5%, respectively), but larger trunk inclination and lumbar flexion were required (p < 0.001 in both).
Collectively, the lower extremity sitting posture significantly changed the way to observe the tablet by adopting more head flexion in neutral and lowered leg conditions or more trunk flexion in raised leg condition.
Time for Korean wildlife conservation Borzée, Amaël; Struecker, Marie-Yon; Yi, Yoonjung ...
Science (American Association for the Advancement of Science),
03/2019, Volume:
363, Issue:
6432
Journal Article
Increasing concerns about musculoskeletal disorders in the upper back arising from excessive daily use of the smartwatch have been widely validated by the rising prevalence of discomfort. This study ...explored the smartwatch as a potential ergonomic intervention over the smartphone. Fourteen healthy participants completed five tasks (application setting, calling, message typing, message checking and vocal message entry) with smartphone and smartwatch in both sitting and standing postures. The neck-shoulder kinematics and muscle activation levels were monitored to assess the effects of the tasks, devices, and postures. The results indicated greater head flexion, head rotation and shoulder abduction and greater muscle activities for smartwatch use compared to smartphone use, but the performance measure (i.e., elapsed time) was superior for smartwatch use in all tasks except message typing. Collectively, only short and simple tasks such as message checking and application setting should be conducted with the smartwatch.
•Biomechanical workloads of smartphone and smartwatch were examined.•Smartwatch showed greater head flexion, head rotation and shoulder abduction.•Smartwatch showed greater muscle activities in deltoid and trapezius.•Smartwatch showed better performance in application setting and message checking.•Smartwatch showed significantly lower subjective discomfort in message checking.
