Molecular phylogeny of rhynchonellide articulate brachiopods (Brachiopoda, Rhynchonellida)

2013 ◽  
Vol 87 (2) ◽  
pp. 211-216 ◽  
Author(s):  
Bernard L. Cohen ◽  
Maria Aleksandra Bitner

We present here the first report based on phylogenetic analyses of small subunit (SSU/18S) and large subunit (LSU/28S) ribosomal DNA (rDNA) sequences from a wider-than-token sample of rhynchonellide articulate brachiopods, with data from 11 of ∼20 extant genera (12 species) belonging to all four extant superfamilies. Data exploration by network and saturation analyses shows that the molecular sequence data are free from major aberrations and are suitable for phylogenetic reconstruction despite the presence of large deletions in four SSU rDNA sequences. Although molecular sequence analyses cannot directly illuminate the systematics of fossils, the independent, genealogical evidence and phylogenetic inferences about extant forms that they make possible are highly relevant to paleontological systematics because they highlight the limitations of evolutionary inference from morphology. Parsimony, distance, maximum likelihood (no clock) and Bayesian (relaxed-clock) analyses all find a tree topology that disagrees strongly with the existing superfamily classification. All tested phylogenetic reconstructions agree that the taxa analyzed fall into three clades designated A1, A2, and B that reflect two major divergence events. The relaxed-clock analysis indicates that clades A and B diverged in the Paleozoic, while clades A1 and A2 reflect Permo-Triassic (and later) events. Morphological homoplasy and possible gene co-option are suggested as the main sources for the discord between the morpho-classification, the results of cladistic analyses of morphology, and the relationships reconstructed from molecular sequences. The origin, function and evolutionary implications of the deletion-bearing rhynchonellide SSU rDNA sequences are briefly discussed in relation to pseudogenes and concerted evolution in the rDNA genomic region.

Zootaxa ◽  
2017 ◽  
Vol 4312 (1) ◽  
pp. 194 ◽  
Author(s):  
ANNIKA PIETERSE ◽  
ANTOINETTE P. MALAN ◽  
LAURA M. KRUITBOS ◽  
WILLEM SIRGEL ◽  
JENNA L. ROSS

A survey of nematodes that use terrestrial slugs as definitive hosts, was conducted in canola fields and ornamental nurseries located in the Western Cape province of South Africa. A total of 3290 slugs were collected from 22 different sites. On the identification of the slugs, they were vivisected and examined for internal nematodes. After identifying the nematodes found, on the basis of their morphological characteristics, their identity was confirmed using molecular sequence data for the internal transcribed spacer (ITS-1, 5.8S, ITS-2), D2-D3 expansion segments of the large subunit (LSU or 28S) and small subunit (SSU or 18S) ribosomal DNA. Of the 22 sites investigated, 13 had nematodes present, with 8 % of the slugs being found to be infected with nematodes. Seven nematode species were confirmed, including Agfa flexilis, Angiostoma margaretae, Angiostoma sp. (SA1), Caenorhabditis elegans, mermithid sp. (SA1), Phasmarhabditis sp. (SA3) and Phasmarhabditis sp. (SA4). In addition, several Angiostoma spp. were also isolated, but could only be identified to genus level due to limited material. Of the seven confirmed species, four were previously undescribed. This is the first record of A. margaretae associating with Deroceras panormitanum, Deroceras reticulatum, Lehmannia valentiana and Oopelta polypunctata. Also, this is the first time that a mermithid has been found associating with molluscs in South Africa. 


2015 ◽  
Vol 65 (Pt_9) ◽  
pp. 3216-3225 ◽  
Author(s):  
Xiaoteng Lu ◽  
Chen Shao ◽  
Yuhe Yu ◽  
Alan Warren ◽  
Jie Huang

The oxytrichid species Pleurotricha curdsi (Shi et al., 2002) Gupta et al., 2003, isolated from a tributary of the Yangtze River in the Mudong district of Chongqing, southern China, was reinvestigated with emphasis on its morphology, morphogenesis and small-subunit (SSU) rDNA-based phylogeny. Compared with three previously described populations, the Mudong population of P. curdsi is characterized by its large body size, 170–295 × 65–110 μm in vivo, and by having a variable number of right marginal rows, either two or three. Likewise, the number of right marginal rows anlagen (RMA) is also variable, i.e. usually two, but sometimes several small extra anlagen that give rise to the formation of the third row, are present to the left of the RMAs. We posit that the Mudong population is an intermediate form between the three previously described populations. Phylogenetic analyses based on the SSU rDNA sequence data show that all populations of P. curdsi cluster with the type species of the genus, Pleurotricha lanceolata, in a clade nested within the Oxytrichidae.


Mammalia ◽  
2019 ◽  
Vol 83 (2) ◽  
pp. 180-189 ◽  
Author(s):  
Adam W. Ferguson ◽  
Houssein R. Roble ◽  
Molly M. McDonough

AbstractThe molecular phylogeny of extant genets (Carnivora, Viverridae,Genetta) was generated using all species with the exception of the Ethiopian genetGenetta abyssinica. Herein, we provide the first molecular phylogenetic assessment ofG. abyssinicausing molecular sequence data from multiple mitochondrial genes generated from a recent record of this species from the Forêt du Day (the Day Forest) in Djibouti. This record represents the first verified museum specimen ofG. abyssinicacollected in over 60 years and the first specimen with a specific locality for the country of Djibouti. Multiple phylogenetic analyses revealed conflicting results as to the exact relationship ofG. abyssinicato otherGenettaspecies, providing statistical support for a sister relationship to all other extant genets for only a subset of mitochondrial analyses. Despite the inclusion of this species for the first time, phylogenetic relationships amongGenettaspecies remain unclear, with limited nodal support for many species. In addition to providing an alternative hypothesis of the phylogenetic relationships among extant genets, this recent record provides the first complete skeleton of this species to our knowledge and helps to shed light on the distribution and habitat use of this understudied African small carnivore.


2021 ◽  
Vol 12 ◽  
Author(s):  
Qi Gao ◽  
Chen Shao ◽  
Qiuyue Tang ◽  
Jingbao Li

The morphology and morphogenesis of Pseudosincirra longicirrata nov. gen. and nov. comb., isolated from southern China, were investigated with living observation and protargol staining. Our population is similar to the original population in living characteristics and ciliary patterns. The main determinable morphogenetic features of P. longicirrata nov. comb. are the presence of five frontoventral-transverse cirral anlagen (FVT-anlagen) and a dorsomarginal kinety anlage. According to the origin of FVT-anlagen IV and V in proter, it can be determined that P. longicirrata nov. comb. possesses two frontoventral rows and one right marginal row. Hence, a new genus, Pseudosincirra nov. gen., is proposed, and the diagnosis of P. longicirrata nov. comb. is improved. The new genus is diagnosed as follows: adoral zone of membranelles and undulating membranes is in a Gonostomum pattern; there are three enlarged frontal cirri, one buccal cirrus, and one parabuccal cirrus; postperistomial cirrus and transverse cirri are lacking; there are two more or less long frontoventral rows and one right and two or more left marginal rows; cirri within all rows very widely spaced; dorsal kinety pattern is of Urosomoida type, that is, three dorsal kineties and one dorsomarginal kinety; and caudal cirri are present. Phylogenetic analyses based on the small subunit ribosomal (SSU rDNA) sequence data indicate that P. longicirrata nov. comb. clusters with Deviata and Perisincirra. It is considered that Pseudosincirra nov. gen. and Perisincirra paucicirrata should be assigned to the family Deviatidae; fine cirri, and cirri within all rows being relatively widely spaced, should be considered as plesiomorphies of Deviatidae; and Deviatidae is closely related to Dorsomarginalia or Strongylidium–Hemiamphisiella–Pseudouroleptus.


Zootaxa ◽  
2020 ◽  
Vol 4811 (1) ◽  
pp. 1-63
Author(s):  
KATHRYN M. WEGLARZ ◽  
CHARLES R BARTLETT

The planthopper genus Chionomus Fennah, 1971 (Hemiptera: Fulgoroidea: Delphacidae) currently includes three Neotropical species, removed from the polyphyletic genus Delphacodes Fieber, 1866. Morphological and molecular evidence further redefine Chionomus to include ten additional species (eight species removed from Delphacodes, two described as new, viz. Chionomus dolonus n. sp. and C. herkos n. sp.), with another four species synonymized. Phylogenetic analyses of morphological and molecular sequence data of the mitochondrial gene Cytochrome Oxidase I provide support for the monophyly of Chionomus. We use a mixed model Bayesian optimality criterion to define phylogenetic relationships among Chionomus and support paraphyly of the original definition of Chionomus (with respect to Delphacodes) and monophyly of the revised genus. 


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Yi-Fan Cao ◽  
Hui-Xia Chen ◽  
Yang Li ◽  
Dang-Wei Zhou ◽  
Shi-Long Chen ◽  
...  

Abstract Background The Tibetan antelope Pantholops hodgsonii (Abel) (Artiodactyla: Bovidae) is an endangered species of mammal endemic to the Qinghai-Tibetan Plateau. Parasites and parasitic diseases are considered to be important threats in the conservation of the Tibetan antelope. However, our present knowledge of the composition of the parasites of the Tibetan antelope remains limited. Methods Large numbers of nematode parasites were collected from a dead Tibetan antelope. The morphology of these nematode specimens was observed using light and scanning electron microscopy. The nuclear and mitochondrial DNA sequences, i.e. small subunit ribosomal DNA (18S), large subunit ribosomal DNA (28S), internal transcribed spacer (ITS) and cytochrome c oxidase subunit 1 (cox1), were amplified and sequenced for molecular identification. Moreover, phylogenetic analyses were performed using maximum likelihood (ML) inference based on 28S and 18S + 28S + cox1 sequence data, respectively, in order to clarify the systematic status of these nematodes. Results Integrated morphological and genetic evidence reveals these nematode specimens to be a new species of pinworm Skrjabinema longicaudatum (Oxyurida: Oxyuridae). There was no intraspecific nucleotide variation between different individuals of S. longicaudatum n. sp. in the partial 18S, 28S, ITS and cox1 sequences. However, a high level of nucleotide divergence was revealed between the new species and its congeners in 28S (8.36%) and ITS (20.3–23.7%) regions, respectively. Molecular phylogenetic results suggest that the genus Skrjabinema should belong to the subfamily Oxyurinae (Oxyuroidea: Oxyuridae), instead of the subfamily Syphaciidae or Skrjabinemiinae in the traditional classification, as it formed a sister relationship to the genus Oxyuris. Conclusions A new species of pinworm Skrjabinema longicaudatum n. sp. (Oxyurida: Oxyuridae) is described. Skrjabinema longicaudatum n. sp. represents the first species of Oxyurida (pinworm) and the fourth nematode species reported from the Tibetan antelope. Our results contribute to the knowledge of the species diversity of parasites from the Tibetan antelope, and clarify the systematic position of the genus Skrjabinema.


1993 ◽  
Vol 71 (9) ◽  
pp. 1249-1265 ◽  
Author(s):  
G. Hausner ◽  
J. Reid ◽  
G. R. Klassen

Phylogenetic analysis of partial rDNA sequences suggests that Ophiostoma should remain the sole genus of the Ophiostomataceae, and this should be the sole family within the Ophiostomatales, whereas Ceratocystis s.s. would be best disposed within the Microascales. Although morphological criteria suggest that the genus Ophiostoma is heterogeneous, analysis of partial small subunit rDNA sequence data shows that Ophiostoma (excluding O. roraimense) represents a monophyletic taxon. Analysis of a partial large subunit rDNA data set, which included sequences from 55 species assignable to Ophiostoma, failed to support the strict subdivision of the genus based on either ascospore characters or the nature of the anamorph. Key words: Ceratocystis, Microascus, Ophiostoma, partial rDNA sequences, phylogeny.


2007 ◽  
Vol 21 (3) ◽  
pp. 207 ◽  
Author(s):  
Ronald M. Clouse ◽  
Gonzalo Giribet

Opiliones (harvestmen) in the suborder Cyphophthalmi are not known to disperse across oceans and each family in the suborder is restricted to a clear biogeographic region. While undertaking a revisionary study of the South-east Asian family Stylocellidae, two collections of stylocellids from New Guinea were noted. This was a surprising find, since the island appears never to have had a land connection with Eurasia, where the rest of the family members are found. Here, 21 New Guinean specimens collected from the westernmost end of the island (Manokwari Province, Indonesia) are described and their relationships to other cyphophthalmids are analysed using molecular sequence data. The specimens represent three species, Stylocellus lydekkeri, sp. nov., S. novaguinea, sp. nov. and undescribed females of a probable third species, which are described and illustrated using scanning electron microscope and stereomicroscope photographs. Stylocellus novaguinea, sp. nov. is described from a single male and it was collected with a juvenile and the three females of the apparent third species. Molecular phylogenetic analyses indicate that the new species are indeed in the family Stylocellidae and they therefore reached western New Guinea by dispersing through Lydekker’s line – the easternmost limit of poor dispersers from Eurasia. The New Guinean species may indicate at least two episodes of oceanic dispersal by Cyphophthalmi, a phenomenon here described for the first time. Alternatively, the presence in New Guinea of poor dispersers from Eurasia may suggest novel hypotheses about the history of the island.


Author(s):  
Maria Aleksandra Bitner ◽  
Bernard L. Cohen ◽  
Sarah. L. Long ◽  
Bertrand Richer de Forges ◽  
Michiko Saito

ABSTRACTThis paper describes a terebratelloid articulate brachiopod, Gyrothyris williamsi sp. nov., based on 95 specimens from seamounts on the Lord Howe Rise, Coral Sea, SW Pacific Ocean. The new species is attributed to Gyrothyris on the basis of (a) morphological and growth trajectory similarities; (b) phylogenetic analyses of an alignment of DNA sequence (∼2900-sites) obtained from nuclear-encoded small- and large-subunit ribosomal RNA genes (SSU and LSU); and (c) the presence of a distinctive, two-part deletion in the LSU gene. It is distinguished morphologically from Gyrothyris mawsoni and its subspecies by both internal and external morphology and by its isolated geographical distribution, which extends the patchy, known range of this genus to an area some 2000 km north of its previous northern limit around New Zealand. Phylogenetic analyses of the rDNAs and of mitochondrial cox1 gene sequences (663 sites) confirm previous indications that the New Zealand endemic terebratelloid genera form a clade (Neothyris (Calloria, Gyrothyris, Terebratella), but the position of Terebratella with respect to Calloria and Gyrothyris remains weakly established. These sequences disagree inexplicably about the closeness of the relationship between Neothyris parva and N. lenticularis. Analyses of the first sequences from Calloria variegata, a species restricted to the Hauraki Gulf, New Zealand, are consistent with the possibility that it originated locally, and recently, from C. inconspicua. Magellania venosa from S. America/Falklands joins with Antarctic Magellania fragilis and M. joubini to form an rDNA clade that excludes Terebratalia as the putative sister-group of the New Zealand terebratelloid clade. The cox1 (but not the rDNA) sequences of the New Zealand clade pass a test for clock-like rates of evolution, and maximum likelihood pairwise distances suggest that if genetic isolation between the ancestor of Antarctic Magellania and the last common ancestor of the New Zealand terebratelloid clade was initiated by separation of the Antarctic and New Zealand plates ∼90 Mya, isolation from M. venosa was initiated earlier, perhaps ∼145 Mya. However, in the simple phylogenetic reconstruction presented here from cox1 sequences, S. American and Antarctic Magellania spp. do not yield a well-supported clade, perhaps because of differences in base composition.


2010 ◽  
Vol 60 (8) ◽  
pp. 1962-1977 ◽  
Author(s):  
Chitchai Chantangsi ◽  
Brian S. Leander

Environmental DNA surveys have revealed a great deal of hidden diversity within the Cercozoa. An investigation into the biodiversity of heterotrophic flagellates in marine benthic habitats of British Columbia, Canada, demonstrated the presence of several undescribed taxa with morphological features that resemble the cercozoan genera Cryothecomonas and Protaspis. Nine novel species of marine interstitial cercozoans are described that are distributed into five genera, four of which are new. Phylogenetic analyses of small subunit rDNA sequences derived from two uncultured isolates of Protaspis obliqua and nine novel cercozoan species (within four novel genera) provided organismal anchors that helped establish the cellular identities of several different environmental sequence clades. These data, however, also showed that the rarity of distinctive morphological features in cryomonads, and other groups of cercozoans, makes the identification and systematics of the group very difficult. Therefore, a DNA barcoding approach was applied as a diagnostic tool for species delimitation that used a 618 bp region at the 5′ end of the SSU rDNA sequence. Nucleotide sequence analysis of this region showed high intergeneric sequence divergences of about 7 % and very low intraspecific sequence divergences of 0–0.5 %; phylogenetic analyses inferred from this barcoding region showed very similar tree topologies to those inferred from the full-length sequence of the gene. Overall, this study indicated that the 618 bp barcoding region of SSU rDNA sequences is a useful molecular signature for understanding the biodiversity and interrelationships of marine benthic cercozoans.


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