scholarly journals Resolving cryptic species complexes in marine protists: phylogenetic haplotype networks meet global DNA metabarcoding datasets

2021 ◽  
Author(s):  
Daniele De Luca ◽  
Roberta Piredda ◽  
Diana Sarno ◽  
Wiebe H.C.F. Kooistra
Keyword(s):  
Gene Flow ◽  
Cryptic Species ◽  
Phylogenetic Trees ◽  
Distribution Patterns ◽  
Chaetoceros Curvisetus ◽  
Haplotype Networks ◽  
Species Complexes ◽  
Biogeographic Regions ◽  
Ocean Sampling ◽  
Marine Protists

AbstractMarine protists have traditionally been assumed to be lowly diverse and cosmopolitan. Yet, several recent studies have shown that many protist species actually consist of cryptic complexes of species whose members are often restricted to particular biogeographic regions. Nonetheless, detection of cryptic species is usually hampered by sampling coverage and application of methods (e.g. phylogenetic trees) that are not well suited to identify relatively recent divergence and ongoing gene flow. In this paper, we show how these issues can be overcome by inferring phylogenetic haplotype networks from global metabarcoding datasets. We use the Chaetoceros curvisetus (Bacillariophyta) species complex as study case. Using two complementary metabarcoding datasets (Ocean Sampling Day and Tara Oceans), we equally resolve the cryptic complex in terms of number of inferred species. We detect new hypothetical species in both datasets. Gene flow between most of species is absent, but no barcoding gap exists. Some species have restricted distribution patterns whereas others are widely distributed. Closely related taxa occupy contrasting biogeographic regions, suggesting that geographic and ecological differentiation drive speciation. In conclusion, we show the potential of the analysis of metabarcoding data with evolutionary approaches for systematic and phylogeographic studies of marine protists.

scholarly journals Genetic differentiation of the southern population of the fathead minnow Pimephales promelas Rafinesque (Actinopterygii: Cyprinidae)

2018 ◽  
Author(s):  
Nayarit E Ballesteros-Nova ◽  
Rodolfo Pérez-Rodríguez ◽  
Rosa G Beltrán-López ◽  
Omar Domínguez-Domínguez
Keyword(s):  
Phylogenetic Trees ◽  
Pimephales Promelas ◽  
Phylogenetic Reconstruction ◽  
Genetic Distances ◽  
Tectonic Events ◽  
Phylogenetic Studies ◽  
Haplotype Networks ◽  
Species Complexes ◽  
Well Differentiated ◽  
Cabeza De Vaca

Background. Mexico is one of the most megadiverse countries in the world, with considerable reaches and endemicity in the diversity of fishes compared to other countries and regions. Recent phylogenetic studies in co-distributed species of widespread fishes, besides revealing a subestimation of species richness in the Mesa del Norte, in Mexico, suggest phylogenetic congruence in some species complexes. Previous morphological and meristic analyses concluded that at least three subspecies of Pimephales promelas exist in United States populations, suggesting that the richness in Pimephales could be underestimated. But no studies have examined the morphologic and genetic diversity in Southern populations of Pimephales promelas. We presented analyses of the genetic variation among P. promelas populations across its Southern distributional range. Methods. Phylogenetic reconstruction and genetic distances using cytochrome b and S7 sequences were done. Results. The results based on phylogenetic trees, species tree, genetic distances and haplotype networks revealed the existence of at least four well-differentiated lineages (Yaqui Lineage, Nazas+Conchos Lineage, Santa Maria Lineage and Casas Grandes Lineage). Discussion. The four well supported lineages found confirm Pimephales promelas as a species complex. Composition and distribution of these major lineages is also consistent with previous biogeographic hypothesis for other fishes in the region, supporting the fragmentation of the ancestral Lake Cabeza de Vaca, possibly due to the combined influence of tectonic events and increasing regional aridity, as well as events of interchange between basins via stream capture.

scholarly journals First Evidence of Cryptic Species Diversity and Population Structuring of Selaroides leptolepis in the Tropical Western Pacific

2021 ◽  
Vol 8 ◽  
Author(s):  
Lorenzo C. Halasan ◽  
Paul John L. Geraldino ◽  
Hsiu-Chin Lin
Keyword(s):  
Genetic Structure ◽  
Cryptic Species ◽  
Phylogenetic Trees ◽  
Rapid Expansion ◽  
Western Pacific ◽  
Genetic Structuring ◽  
Tropical Western Pacific ◽  
Haplotype Networks ◽  
Population Structuring ◽  
Genetic Structure And Diversity

The yellowstripe scad, Selaroides leptolepis (Carangidae), is an important fish commodity in the Tropical Western Pacific (TWP). It has a latitudinal Pacific range from south of Japan down to northern Australia, with the highest concentration in Southeast Asia. However, its TWP fishing grounds have long been a hotspot of unsustainable exploitations, thus threatening the remaining wild populations. Despite the species’ commercial significance, there is limited understanding of its genetic structure and diversity. Herein, the genetic structure of S. leptolepis was examined using mitochondrial COI and CytB sequences. Both markers denoted significant genetic structuring based on high overall FST values. Hierarchical analysis of molecular variance (AMOVA), maximum likelihood (ML) phylogenetic trees, and median-joining (MJ) haplotype networks strongly supported the occurrence of two allopatrically distributed lineages. These comprised of a widespread Asian lineage and an isolated Australian lineage. Within-lineage distances were low (K2P < 1%) whereas across-lineage distances were remarkably high (K2P > 6%), already comparable to that of interspecific carangid divergences. Haplotype sequence memberships, high genetic variations, and the geographic correlation suggested that the Australian lineage was a putative cryptic species. Historical demographic inferences also revealed that the species experienced rapid expansion commencing on the late Pleistocene, most likely during the end of the Last Glacial Maximum (∼20,000 years ago). The present study encouraged the application of lineage-specific management efforts, as the lineages are experiencing different evolutionary pressures. Overall, accurate knowledge of the species’ genetic distribution is fundamental in protecting its diversity and assuring stock sustainability.

scholarly journals Genetic differentiation of the southern population of the fathead minnow Pimephales promelas Rafinesque (Actinopterygii: Cyprinidae)

2018 ◽  
Author(s):  
Nayarit E Ballesteros-Nova ◽  
Rodolfo Pérez-Rodríguez ◽  
Rosa G Beltrán-López ◽  
Omar Domínguez-Domínguez
Keyword(s):  
Phylogenetic Trees ◽  
Pimephales Promelas ◽  
Phylogenetic Reconstruction ◽  
Genetic Distances ◽  
Tectonic Events ◽  
Phylogenetic Studies ◽  
Haplotype Networks ◽  
Species Complexes ◽  
Well Differentiated ◽  
Cabeza De Vaca

Background. Mexico is one of the most megadiverse countries in the world, with considerable reaches and endemicity in the diversity of fishes compared to other countries and regions. Recent phylogenetic studies in co-distributed species of widespread fishes, besides revealing a subestimation of species richness in the Mesa del Norte, in Mexico, suggest phylogenetic congruence in some species complexes. Previous morphological and meristic analyses concluded that at least three subspecies of Pimephales promelas exist in United States populations, suggesting that the richness in Pimephales could be underestimated. But no studies have examined the morphologic and genetic diversity in Southern populations of Pimephales promelas. We presented analyses of the genetic variation among P. promelas populations across its Southern distributional range. Methods. Phylogenetic reconstruction and genetic distances using cytochrome b and S7 sequences were done. Results. The results based on phylogenetic trees, species tree, genetic distances and haplotype networks revealed the existence of at least four well-differentiated lineages (Yaqui Lineage, Nazas+Conchos Lineage, Santa Maria Lineage and Casas Grandes Lineage). Discussion. The four well supported lineages found confirm Pimephales promelas as a species complex. Composition and distribution of these major lineages is also consistent with previous biogeographic hypothesis for other fishes in the region, supporting the fragmentation of the ancestral Lake Cabeza de Vaca, possibly due to the combined influence of tectonic events and increasing regional aridity, as well as events of interchange between basins via stream capture.

scholarly journals Co-occurring cryptic species pose challenges for conservation: a case study of the African dwarf crocodile (Osteolaemusspp.) in Cameroon

Oryx ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 584-590 ◽  
Author(s):  
Nicole L. Smolensky
Keyword(s):  
Cryptic Species ◽  
Conservation Status ◽  
Taxonomic Revision ◽  
Single Species ◽  
Conservation Strategies ◽  
Encounter Rates ◽  
Distribution Maps ◽  
Species Complexes ◽  
Threatened Taxa ◽  
Population Structures

AbstractThe conservation status of threatened taxa may be obfuscated by the detection of cryptic species complexes, in both vertebrate and invertebrate species. African dwarf crocodiles (Osteolaemusspp.) are hunted throughout their range but their conservation status is unknown. Few population assessments have been carried out and there has been a taxonomic revision of the number of species in the genus. The similar morphologies ofOsteolaemus tetraspisandOsteolaemus osbornipose a challenge for conservation in Cameroon, where they are still managed as a single species. Nocturnal spotlight surveys were conducted in three regions during August–November 2010 and December 2011–February 2012 to provide population assessments ofO. tetraspisandO. osborniand raise awareness of the two species in Cameroon. The mean encounter rates ofO. tetraspisandO. osborniwere 1.02 ± SD 1.34 (65 individuals in 39 surveys) and 0.61 ± SD 0.38 (three in four surveys) crocodiles per km, respectively. TheO. tetraspispopulation comprised juveniles predominantly and had a male-biased sex ratio. The fewO. osbornidetected comprised both adults and juveniles. Both species are threatened in Cameroon, based on low encounter rates, young population structures and the threats of habitat loss and hunting pressure. This study provides distribution maps and serves as a baseline to quantify population trends and inform conservation strategies.

scholarly journals Biology and bionomics of malaria vectors in India: existing information and what more needs to be known for strategizing elimination of malaria

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Sarala K. Subbarao ◽  
Nutan Nanda ◽  
Manju Rahi ◽  
Kamaraju Raghavendra
Keyword(s):  
Vector Control ◽  
Distribution Patterns ◽  
Time Frame ◽  
Malaria Vectors ◽  
Effective Implementation ◽  
Species Complexes ◽  
Biological Characters ◽  
The Government ◽  
National Framework ◽  
Long Lasting Insecticidal Nets

AbstractIndia has committed to eliminate malaria by 2030. The national framework for malaria elimination released by the Government of India plans to achieve this goal through strategic planning in a phased manner. Since vector control is a major component of disease management and vector elimination, it requires a thorough understanding of the biology and bionomics of malaria vectors exhibiting definite distribution patterns in diverse ecosystems in the country. Although a wealth of information is available on these aspects, lesser-known data are on biting time and rhythm, and the magnitude of outdoor transmission by the vectors which are crucial for effective implementation of the key vector control interventions. Most of the data available for the vector species are at sensu lato level, while the major vectors are species complexes and their members distinctly differ in biological characters. Furthermore, the persistent use of insecticides in indoor residual spray and long-lasting insecticidal nets has resulted in widespread resistance in vectors and changes in their behaviour. In this document, challenges in vector control in the Indian context have been identified and possible solutions to overcome the problem are suggested. Adequate addressing of the issues raised would greatly help make a deep dent in malaria transmission and consequently result in disease elimination within the targeted time frame.

Cryptic species complexes in manipulative echinostomatid trematodes: when two become six

Parasitology ◽  
2008 ◽  
Vol 136 (2) ◽  
pp. 241-252 ◽  
Author(s):  
T. L. F. LEUNG ◽  
D. B. KEENEY ◽  
R. POULIN
Keyword(s):  
Cryptic Species ◽  
Phylogenetic Analyses ◽  
Morphological Characteristics ◽  
Single Species ◽  
Distinct Species ◽  
Molecular Data ◽  
Spatial Segregation ◽  
Small Scale ◽  
Intermediate Hosts ◽  
Species Complexes

SUMMARYRecent studies have shown that some digenean trematodes previously identified as single species due to the lack of distinguishing morphological characteristics actually consist of a number of genetically distinct cryptic species. We obtained mitochondrial 16S and nuclear ITS1 sequences for the redial stages of Acanthoparyphium sp. and Curtuteria australis collected from snails and whelks at various locations around Otago Peninsula, New Zealand. These two echinostomes are well-known host manipulators whose impact extends to the entire intertidal community. Using phylogenetic analyses, we found that Acanthoparyphium sp. is actually composed of at least 4 genetically distinct species, and that a cryptic species of Curtuteria occurs in addition to C. australis. Molecular data obtained for metacercariae dissected from cockle second intermediate hosts matched sequences obtained for Acanthoparyphium sp. A and C. australis rediae, respectively, but no other species. The various cryptic species of both Acanthoparyphium and Curtuteria also showed an extremely localized pattern of distribution: some species were either absent or very rare in Otago Harbour, but reached far higher prevalence in nearby sheltered inlets. This small-scale spatial segregation is unexpected as shorebird definitive hosts can disperse trematode eggs across wide geographical areas, which should result in a homogeneous mixing of the species on small geographical scales. Possible explanations for this spatial segregation of the species include sampling artefacts, local adaptation by first intermediate hosts, environmental conditions, and site fidelity of the definitive hosts.

Cryptic species in sympatry: nonrandom small-scale distribution patterns inBostrychia intricata(Ceramiales, Rhodophyta)

Phycologia ◽  
2016 ◽  
Vol 55 (4) ◽  
pp. 424-430 ◽  
Author(s):  
Narongrit Muangmai ◽  
Ulla von Ammon ◽  
Giuseppe C. Zuccarello
Keyword(s):  
Cryptic Species ◽  
Distribution Patterns ◽  
Small Scale

scholarly journals Historical biogeography of two cosmopolitan families of flowering plants: Annonaceae and Rhamnaceae

2004 ◽  
Vol 359 (1450) ◽  
pp. 1495-1508 ◽  
Author(s):  
J. E. Richardson ◽  
L. W. Chatrou ◽  
J. B. Mols ◽  
R. H. J. Erkens ◽  
M. D. Pirie
Keyword(s):  
Dna Sequences ◽  
Phylogenetic Trees ◽  
Phylogenetic Analyses ◽  
Plastid Dna ◽  
Distribution Patterns ◽  
Historical Biogeography ◽  
Rate Heterogeneity ◽  
Long Distance ◽  
Fossil Calibration ◽  
Dispersal Capability

Annonaceae are a pantropically distributed family found predominantly in rainforests, so they are megathermal taxa, whereas Rhamnaceae are a cosmopolitan family that tend to be found in xeric regions and may be classified as mesothermal. Phylogenetic analyses of these families are presented based on rbcL and trn L–F plastid DNA sequences. Likelihood ratio tests revealed rate heterogeneity in both phylogenetic trees and they were therefore made ultrametric using non–parametric rate smoothing and penalized likelihood. Divergence times were then estimated using fossil calibration points. The historical biogeography of these families that are species rich in different biomes is discussed and compared with other published reconstructions. Rhamnaceae and most lineages within Annonaceae are too young to have had their distribution patterns influenced by break–up of previously connected Gondwanan landmasses. Contrasts in the degree of geographical structure between these two families may be explained by differences in age and dispersal capability. In both groups, long–distance dispersal appears to have played a more significant role in establishing modern patterns than had previously been assumed. Both families also contain examples of recent diversification of species–rich lineages. An understanding of the processes responsible for shaping the distribution patterns of these families has contributed to our understanding of the historical assembly of the biomes that they occupy.

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