scholarly journals The role of allopatric speciation and ancient origins of Bathynellidae (Crustacea) in the Pilbara (Western Australia): two new genera from the De Grey River catchment

2019 ◽  
Vol 88 (4) ◽  
pp. 452-497
Author(s):  
Giulia Perina ◽  
Ana I. Camacho ◽  
Joel Huey ◽  
Pierre Horwitz ◽  
Annette Koenders

The stygofaunal family of Bathynellidae, is an excellent group to study the processes that shape diversity and distribution, since they have unknown surface or marine relatives, high level of endemism, and limited dispersal abilities. Recent research on Bathynellidae in Western Australia (Pilbara) has uncovered new taxa with unexpected distributions and phylogenetic relationships, but the biogeographical processes that drive their diversification on the continent are still unclear. By exploring the diversity, distribution, and divergence time of Bathynellidae in a setting such as the perched and isolated aquifers of the Cleaverville Formation in the north of the De Grey River catchment (Pilbara), we aim to test the hypothesis that vicariance has shaped the distribution of this family, specifically if one or multiple vicariant events were involved. We analysed the specimens collected from perched water in different plateaus of the Cleaverville Formation, combining morphological and molecular data from mitochondrial and nuclear genes. We described two new species and genera (Anguillanella callawaensis gen. et sp. nov. and Muccanella cundalinensis gen. et sp. nov.), and two additional taxa are recognised using morphology and/or Automatic Barcode Gap Discovery and Poisson Tree Processes species delimitation methods. New genera and species result restricted to isolate perched aquifers on single plateaus and their distributions, phylogenetic relationships, and divergence time estimates support multiple vicariant events and ancient allopatric speciation.

1968 ◽  
Vol 100 (S58) ◽  
pp. 5-112 ◽  
Author(s):  
Margaret Rae MacKay

AbstractThe North American Aegeriidae are revised on the basis of the study of late-instar larvae of about 60 species. These species represent 20 genera in five tribes in two subfamilies: Bembeciini, Zenodoxini, Aegeriini and Melittiini in Zenodoxinae and Synanthedontini in Synanthedontinae. The presently recognized genera, Ramosia Engelhardt, Conopia Hübner and Thamnosphecia Spuler are reduced to synonyms of Synanthedon Hübner. Three new genera are defined by larval characters but are referred to only as Genera I, II and III. Larval characters for most of the species are discussed and illustrated; keys to species, genera and tribes are provided. Tribes, genera and most species are arranged in the text as nearly as possible according to their phylogenetic relationships as suggested by the larvae.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
James A. Schulte

Methods for estimating divergence times from molecular data have improved dramatically over the past decade, yet there are few studies examining alternative taxon sampling effects on node age estimates. Here, I investigate the effect of undersampling species diversity on node ages of the South American lizard clade Liolaemini using several alternative subsampling strategies for both time calibrations and taxa numbers. Penalized likelihood (PL) and Bayesian molecular dating analyses were conducted on a densely sampled (202 taxa) mtDNA-based phylogenetic hypothesis of Iguanidae, including 92 Liolaemini species. Using all calibrations and penalized likelihood, clades with very low taxon sampling had node age estimates younger than clades with more complete taxon sampling. The effect of Bayesian and PL methods differed when either one or two calibrations only were used with dense taxon sampling. Bayesian node ages were always older when fewer calibrations were used, whereas PL node ages were always younger. This work reinforces two important points: (1) whenever possible, authors should strongly consider adding as many taxa as possible, including numerous outgroups, prior to node age estimation to avoid considerable node age underestimation and (2) using more, critically assessed, and accurate fossil calibrations should yield improved divergence time estimates.


Hacquetia ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 337-347 ◽  
Author(s):  
Mehrshid Riahi ◽  
Farrokh Ghahremaninejad

Abstract Molecular data have been increasingly used to study the phylogenetic relationships among many taxa, including scrophs. Sometimes they have provided phylogenetic reconstructions that are in conflict with morphological data leading to a re-evaluation of long-standing evolutionary hypotheses. In this paper, we review reports of the recent knowledge of the phylogenetic relationships within Scrophularieae (2011–2017). The results of these analyses led to the following conclusions. (1) Species of Scrophularia have undergone one or more Miocene migration events occurred from eastern Asia to the North America with subsequent long dispersal and diversification in three main directions. (2) Allopolyploid and aneuploid hybrid speciation between Scrophularia species can occur, so hybridization and polyploidy have an important role for history of diversification. (3) The ancestral staminode type for the genus Scrophularia seems to be a large staminode. (4) Monophyly of the genus Verbascum with respect to the genus Scrophularia is strongly supported. (5) Oreosolen, is not monophyletic, because all accessions of Oreosolen were nested within Scrophularia. We discuss methods of data collection and analysis, and we describe the areas of conflict and agreement between molecular phylogenies.


2021 ◽  
Vol 46 (2) ◽  
pp. 304-320
Author(s):  
Mónica Míguez ◽  
Pedro Jiménez-Mejías ◽  
Carmen Benítez-Benítez ◽  
Hanno Schaefer ◽  
Santiago Martín-Bravo

Abstract— Populations of Carex sect. Rhynchocystis (Cyperaceae) from the Macaronesian archipelagos (Azores and Madeira) have traditionally been treated either as a variety of the widely distributed Western Palearctic C. pendula, or directly synonymized under it. However, recent phylogenetic studies have shown that Azorean populations of C. pendula display a certain degree of differentiation from mainland plants, while the phylogenetic relationships of Madeiran populations remain unclear. Here we perform an integrated systematic study focused on the Macaronesian populations of Carex sect. Rhynchocystis to elucidate their phylogenetic relationships and taxonomic status. We reconstructed a molecular phylogeny based on five DNA regions and conducted a multivariate morphological analysis. Divergence time estimates show that the Macaronesian populations can be traced back to a Plio-Pleistocene origin. Our results suggest that these island populations of C. pendula are better treated as two distinct species within Carex sect. Rhynchocystis (i.e. C. leviosa from the Azores and C. sequeirae from Madeira). We provide morphological characters to differentiate the new species from C. pendula s. s., detailed descriptions of the three taxa, a revised key for the entire section, as well as detailed analytical drawings of the two newly described species. We also perform a critical evaluation of the taxonomic diversity of Carex in the Azores and Madeira. Finally, we informally assessed the conservation status of the new species at a global scale under IUCN categories and criteria, resulting in the proposal of the categories Least Concern for C. leviosa and Critically Endangered for C. sequeirae.


2006 ◽  
Vol 2 (4) ◽  
pp. 543-547 ◽  
Author(s):  
Per G.P Ericson ◽  
Cajsa L Anderson ◽  
Tom Britton ◽  
Andrzej Elzanowski ◽  
Ulf S Johansson ◽  
...  

Patterns of diversification and timing of evolution within Neoaves, which includes almost 95% of all bird species, are virtually unknown. On the other hand, molecular data consistently indicate a Cretaceous origin of many neoavian lineages and the fossil record seems to support an Early Tertiary diversification. Here, we present the first well-resolved molecular phylogeny for Neoaves, together with divergence time estimates calibrated with a large number of stratigraphically and phylogenetically well-documented fossils. Our study defines several well-supported clades within Neoaves. The calibration results suggest that Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, diversified around or soon after the K/T boundary. Our results thus do not contradict palaeontological data and show that there is no solid molecular evidence for an extensive pre-Tertiary radiation of Neoaves.


2020 ◽  
Author(s):  
Sebastián Escobar ◽  
Andrew J. Helmstetter ◽  
Rommel Montúfar ◽  
Thomas L. P. Couvreur ◽  
Henrik Balslev

AbstractThe vegetable ivory palms (Phytelepheae) form a small group of Neotropical palms whose phylogenetic relationships are not fully understood. Three genera and eight species are currently recognized; however, it has been suggested that Phytelephas macrocarpa could include the species Phytelephas seemannii and Phytelephas schottii because of supposed phylogenetic relatedness and similar morphology. We inferred their phylogenetic relationships and divergence time estimates using the 32 most clock-like loci of a custom palm bait-kit formed by 176 genes and four fossils for time calibration. We additionally explored the historical biogeography of the tribe under the recovered phylogenetic relationships. Our fossil-dated tree showed the eight species previously recognized, and that P. macrocarpa is not closely related to P. seemanii and P. schottii, which, as a consequence, should not be included in P. macrocarpa. The ancestor of the vegetable ivory palms was widely-distributed in the Chocó, the inter-Andean valley of the Magdalena River, and the Amazonia during the Miocene at 19.25 Ma. Early diversification in Phytelephas at 5.27 Ma can be attributed to trans-Andean vicariance between the Chocó/Magdalena and the Amazonia. Our results support the role of Andean uplift in the early diversification of Phytelephas under new phylogenetic relationships inferred from genomic data.


2020 ◽  
Vol 84 (4) ◽  
pp. 317-330
Author(s):  
Francisco J. García-Cárdenas ◽  
Mónica Núñez-Flores ◽  
Pablo J. López-González

Pennatulaceans are an important component of benthic marine communities usually related to soft bottoms. Despite their important ecological role, as yet little is known about their origin and divergence time. The first attempts to establish phylogenetic relationships among genera date from the early 20th century, when only morphological characters were available. In the last decade, phylogenetic analyses based on mitochondrial DNA sequences from a selected number of species have proposed a different hypothetical ancestor for this group, but their intergeneric relationships remain obscure. The present study is based on a combination of mitochondrial and nuclear markers (mtMutS, Cox1 and 28S rDNA), adding new molecular information about the phylogenetic relationships among the pennatulacean genera, including 38 new sequences belonging to 13 different species. Some of the phylogenetic relationships inferred in the present study question the current classification of sea pens based on morphology (at different taxonomic levels), clearly indicating that the two main groups Sessiliflorae and Subselliflorae, some of their main families (e.g. Pennatulidae, Umbellulidae, Virgulariidae) and some genera (e.g. Umbellula, Veretillum) are non-monophyletic. In addition, the veretillids, traditionally considered the most primitive pennatulaceans, are not shown as the earliest-diverging taxon. Moreover, an analysis of divergence time performed here suggested that the origin of the pennatulaceans dates from the Lower Cretaceous (Berriasian, ~144 Ma), in agreement with their sparsely known fossil record, while the initial divergence of most extant genera occurred in the Oligocene and Miocene times.


1969 ◽  
Vol 17 (1) ◽  
pp. 65 ◽  
Author(s):  
JAL Watson

Thirty species of Odonata are known to occur in the north-west of Western Australia, between the De Grey and Gascoyne Rivers. Eight of these species, from the families Coenagrionidae, Protoneuridae, Gomphidae, Corduliidae, and Libellulidae, belong to taxa here described as new. All the north-western dragonflies are either of tropical affinity, or widespread species. The species confined to permanent waters, i.e. to conditions of relatively mild temperatures and high oxygen tensions, are commonly more distinct from closest relatives in the Kimberley region or northern Queensland, than Kimberley and Queensland species are from each other. Such disjunct species show limited dispersal as adults.


Sign in / Sign up

Export Citation Format

Share Document