Phylogeny of Echiura updated, with a revised taxonomy to reflect their placement in Annelida as sister group to Capitellidae

2020 ◽  
Vol 34 (1) ◽  
pp. 101 ◽  
Author(s):  
Ryutaro Goto ◽  
James Monnington ◽  
Marija Sciberras ◽  
Isao Hirabayashi ◽  
Greg W. Rouse

Echiura (commonly called spoon worms) are derived annelids that have an unsegmented sausage-shaped body with a highly extensible anterior end (i.e. a proboscis). Echiura currently contains two superfamilies: Echiurioidea (with Echiuridae, Urechidae and Thalassematidae) and Bonellioidea (with Bonelliidae, and Ikedidae). Ikedidae contains only Ikeda, which is distinctive in having a huge trunk, a highly elongate proboscis with stripes or dots, and numerous gonoducts. A recent molecular phylogeny of Echiura recovered Ikedidae as the sister group to Bonelliidae. However, due to relatively low support values for the monophyly of Bonelliidae, this relationship remains problematic. In this study, we reinvestigated the relationship of Bonelliidae and Ikedidae using an expanded dataset with more taxa and genes. In contrast to the previous results, our analyses strongly support that Ikeda is nested within Bonelliidae due to the placement of Maxmuelleria. On the basis of this result, we synonymise Ikedidae with Bonelliidae and transfer Ikeda to the latter, the diagnosis of which is amended. In addition, we synonymise Urechidae with its sister group Echiuridae because they share the synapomorphy of having anal chaetae rings. Furthermore, considering that recent phylogenetic studies have consistently recovered Echiura as the sister group to Capitelliidae within Annelida, we drop the rank of the echiuran clade to family-level and propose a revised classification: Thalassematidae with two subfamilies, Thalassematinae (with two tribes Echiurini and Thalassematini) and Bonelliinae. In addition, we identified a sample collected from the deep sea (~1820 m) of Monterey Bay, California, based on its molecular data. This terminal unexpectedly formed the sister group to the eight genera of Thalassematini, most members of which are inhabitants of littoral zones.

2008 ◽  
Vol 276 (1655) ◽  
pp. 239-245 ◽  
Author(s):  
Moriya Ohkuma ◽  
Satoko Noda ◽  
Yuichi Hongoh ◽  
Christine A Nalepa ◽  
Tetsushi Inoue

Cryptocercus cockroaches and lower termites harbour obligate, diverse and unique symbiotic cellulolytic flagellates in their hindgut that are considered critical in the development of social behaviour in their hosts. However, there has been controversy concerning the origin of these symbiotic flagellates. Here, molecular sequences encoding small subunit rRNA and glyceraldehyde-3-phosphate dehydrogenase were identified in the symbiotic flagellates of the order Trichonymphida (phylum Parabasalia) in the gut of Cryptocercus punctulatus and compared phylogenetically to the corresponding species in termites. In each of the monophyletic lineages that represent family-level groups in Trichonymphida, the symbionts of Cryptocercus were robustly sister to those of termites. Together with the recent evidence for the sister-group relationship of the host insects, this first comprehensive study comparing symbiont molecular phylogeny strongly suggests that a set of symbiotic flagellates representative of extant diversity was already established in an ancestor common to Cryptocercus and termites, was vertically transmitted to their offspring, and subsequently became diversified to distinct levels, depending on both the host and the symbiont lineages.


IMA Fungus ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Agata Kaczmarek ◽  
Mieczysława I. Boguś

AbstractThe relationship between entomopathogenic fungi and their insect hosts is a classic example of the co-evolutionary arms race between pathogen and target host. The present review describes the entomopathogenic potential of Chytridiomycota and Blastocladiomycota fungi, and two groups of fungal allies: Oomycota and Microsporidia. The Oomycota (water moulds) are considered as a model biological control agent of mosquito larvae. Due to their shared ecological and morphological similarities, they had long been considered a part of the fungal kingdom; however, phylogenetic studies have since placed this group within the Straminipila. The Microsporidia are parasites of economically-important insects, including grasshoppers, lady beetles, bumblebees, colorado potato beetles and honeybees. They have been found to display some fungal characteristics, and phylogenetic studies suggest that they are related to fungi, either as a basal branch or sister group. The Blastocladiomycota and Chytridiomycota, named the lower fungi, historically were described together; however, molecular phylogenetic and ultrastructural research has classified them in their own phylum. They are considered parasites of ants, and of the larval stages of black flies, mosquitoes and scale insects.


2002 ◽  
Vol 71 (4) ◽  
pp. 123-129 ◽  
Author(s):  
Ana Isabel Camacho ◽  
Isabel Rey ◽  
Beatriz A. Dorda ◽  
Annie Machordom ◽  
Antonio G. Valdecasas

Molecular data for the mt 16S rDNA gene fragment of a bathynellacean is here presented for the first time and used to analyze the relationship of the group within the crustacean class Malacostraca (Arthropoda, Bathynellacea). Two contrasting views have classified the bathynelids as being either within the order Syncarida or in a separate super-order Podophallocarida belonging to the infra-class Eonomostraca, a disagreement based mainly on debates over external and internal morphology. The preliminary analyses offered here in question the placement of this Bathynellacea within the Syncarida, and suggest the need for a further study of relationships among the malacostracan groups.


2020 ◽  
Vol 50 (6) ◽  
Author(s):  
Elin A. Thomas ◽  
Ruoyu Liu ◽  
Diva Amon ◽  
Jon T. Copley ◽  
Adrian G. Glover ◽  
...  

AbstractChemosynthetic ecosystems have long been acknowledged as key areas of enrichment for deep-sea life, supporting hundreds of endemic species. Echinoderms are among the most common taxa inhabiting the periphery of chemosynthetic environments, and of these, chiridotid holothurians are often the most frequently observed. Yet, published records of chiridotids in these habitats are often noted only as supplemental information to larger ecological studies and several remain taxonomically unverified. This study therefore aimed to collate and review all known records attributed to Chiridota Eschscholtz, 1829, and to conduct the first phylogenetic analysis into the relationship of these chiridotid holothurians across global chemosynthetic habitats. We show that Chiridota heheva Pawson & Vance, 2004 is a globally widespread, cosmopolitan holothurian that occupies all three types of deep-sea chemosynthetic ecosystem—hydrothermal vents, cold seeps and organic falls—as an organic-enrichment opportunist. Furthermore, we hypothesise that C. heheva may be synonymous with another vent-endemic chiridotid, Chiridota hydrothermica Smirnov et al., 2000, owing to the strong morphological, ecological and biogeographical parallels between the two species, and predict that any chiridotid holothurians subsequently discovered at global reducing environments will belong to this novel species complex. This study highlights the importance of understudied, peripheral taxa, such as holothurians, to provide insights to biogeography, connectivity and speciation at insular deep-sea habitats.


2011 ◽  
Vol 279 (1731) ◽  
pp. 1093-1099 ◽  
Author(s):  
Maria Heikkilä ◽  
Lauri Kaila ◽  
Marko Mutanen ◽  
Carlos Peña ◽  
Niklas Wahlberg

Although the taxonomy of the ca 18 000 species of butterflies and skippers is well known, the family-level relationships are still debated. Here, we present, to our knowledge, the most comprehensive phylogenetic analysis of the superfamilies Papilionoidea, Hesperioidea and Hedyloidea to date based on morphological and molecular data. We reconstructed their phylogenetic relationships using parsimony and Bayesian approaches. We estimated times and rates of diversification along lineages in order to reconstruct their evolutionary history. Our results suggest that the butterflies, as traditionally understood, are paraphyletic, with Papilionidae being the sister-group to Hesperioidea, Hedyloidea and all other butterflies. Hence, the families in the current three superfamilies should be placed in a single superfamily Papilionoidea. In addition, we find that Hedylidae is sister to Hesperiidae, and this novel relationship is supported by two morphological characters. The families diverged in the Early Cretaceous but diversified after the Cretaceous–Palaeogene event. The diversification of butterflies is characterized by a slow speciation rate in the lineage leading to Baronia brevicornis , a period of stasis by the skippers after divergence and a burst of diversification in the lineages leading to Nymphalidae, Riodinidae and Lycaenidae.


1996 ◽  
Vol 128 (2) ◽  
pp. 273-291 ◽  
Author(s):  
Norman F. Johnson

AbstractThe genus Paratelenomus Dodd is revised from a worldwide perspective. Three species are described as new: P. angor [Taiwan, Thailand], P. indivisus [Papua New Guinea, Australia], and P. matinalis [Vanuatu]. Paratelenomus bicolor (Dodd) [Australia], P. saccharalis (Dodd) [southern Europe, Africa, tropical Asia, Australia], P. ophiusa (Dodd) [Papua New Guinea, Australia], P. striativentris (Risbec) [Africa, India], and P. tetartus [Indonesia, Malaysia, Philippines] are redescribed. Aphanurus graeffei Kieffer, 1917 and Asolcus minor Watanabe, 1954 are junior synonyms of P. saccharalis (Dodd), 1913. An identification key to species is provided. The relationship of Paratelenomus within Telenominae is discussed; the hypothesized sister group is Nirupama Nixon.


2003 ◽  
Vol 17 (1) ◽  
pp. 143 ◽  
Author(s):  
Rienk de Jong

A sister-group relationship of endemic taxa in at least two Gondwanan fragments is considered an indication of a possible Gondwanan ancestry. Without a test of the age of the relationship, such an ancestry remains hypothetical. The relationships of all genera and higher taxa endemic to the Australian region with endemic taxa in other fragments of Gondwana are tested. Out of a total of 207 butterfly genera, 96 genera are endemic. Such a relationship is supported by morphological and molecular characters in a number of analyses in only one case(Cressida with Euryades, in South America). Application of a molecular clock, however, shows the relationship to be not older than c. 30 million years, too young to be the result of the break-up of Gondwana. The other endemic genera generally point to a relationship with the Oriental region, but the relationships of a few genera are still obscure. Consequently, claims of a Gondwanan ancestry in butterflies of the Australian region are ill founded. If such an ancestry exists, it has been obscured by later dispersals and extinctions.


2013 ◽  
Vol 753-755 ◽  
pp. 1161-1168
Author(s):  
Qing Jue Han ◽  
Shao Jun Liu

For the deep-sea mining system, tracked vehicle is widely used as a miner. From the data of characteristic of the seabed sediment, on which the miner is walking, the relationship of the traction force of the miner and the slip rate of the track is established. The soil-track interaction, an essential issue in tracked vehicle modeling, has been analyzed in detail. Then the kinematic model of the deep-sea tracked miner is established and a PID control strategy is presented to make the miner walk along the desired path. After a series of computer simulations in MATLAB, the validity of the control strategy is confirmed.


2006 ◽  
Vol 37 (3) ◽  
pp. 257-279 ◽  
Author(s):  
William Wolfe ◽  
Kelly Miller ◽  
Olof Biström

AbstractThe phylogeny of the Hydroporinae is investigated in a cladistic analysis emphasizing placement of the genus Peschetius Guignot, historically placed in the tribe Hydroporini. Sixty-nine adult and larval morphological characters were coded for 61 species of Hydroporinae representing eight of the nine tribes. Cladistic analysis of the data resulted in 396 most parsimonious cladograms (length = 176, CI = 46, RI = 80). The results indicate that the genus Peschetius is the sister group to the tribe Bidessini based mainly on an unambiguous character, the presence of a prominent internal spermathecal spine, and several other more ambiguous or homoplasious characters. The tribe Bidessini is expanded to include the genus Peschetius, and it is formally transferred from the tribe Hydroporini. Other results indicating interesting relationships of tribes and genera within Hydroporinae are also discussed. Results include; 1) a dramatically paraphyletic Hydroporini with Laccornellus Roughley and Wolfe, Canthyporus Zimmermann and Hydrocolus Roughley and Larson in basal positions within the phylogeny, 2) Hydrovatus Motschulsky and Queda Sharp resolved as sister groups and not closely related to Methlini van den Branden, 3) support for close relationship of Pachydrus Sharp (Pachydrini Biström, Nilsson and Wewalka) with Hyphydrini Sharp, 4) paraphyly of Hygrotus Stephens sensu lato with the relationship H. (Coelambus) Thomson + (Hygrotus sensus stricto + Hydrovatini)) suggesting recognition of Coelambus and Hygrotus as separate genera, 5) close relationship between the Australian genera of Hydroporini and Hyphydrini and 6) the nesting of Vatellini within a group of Hydroporini.


2017 ◽  
Author(s):  
Koichiro Tamura ◽  
Qiqing Tao ◽  
Sudhir Kumar

AbstractRelTime estimates divergence times by relaxing the assumption of a strict molecular clock in a phylogeny. It showed excellent performance in estimating divergence times for both simulated and empirical molecular sequence datasets in which evolutionary rates varied extensively throughout the tree. RelTime is computationally efficient and scales well with increasing size of datasets. Until now, however, RelTime has not had a formal mathematical foundation. Here, we show that the basis of the RelTime approach is a relative rate framework (RRF) that combines comparisons of evolutionary rates in sister lineages with the principle of minimum rate change between an evolutionary lineage and its descendants. We present analytical solutions for estimating relative lineage rates and divergence times under RRF. We also discuss the relationship of RRF with other approaches, including the Bayesian framework. We conclude that RelTime will be also useful for phylogenies with branch lengths derived not only from molecular data, but also morphological and biochemical traits.


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