Intraspecific variability of morphological characters in the species-rich deep-sea genus Acantholaimus Allgén, 1933 (Nematoda: Chromadoridae)

Nematology ◽  
2016 ◽  
Vol 18 (4) ◽  
pp. 455-473 ◽  
Author(s):  
Dmitry M. Miljutin ◽  
Maria A. Miljutina
Keyword(s):  
Deep Sea ◽  
Intraspecific Variability ◽  
Morphological Characters ◽  
Molecular Data ◽  
Species Discrimination ◽  
Species Differentiation ◽  
Lateral Field ◽  
Operational Taxonomic Units ◽  
General Arrangement ◽  
Taxonomic Approach

Acantholaimusis a species-rich genus of deep-sea nematodes, often with dozens of species found at the same locality but each represented by single or few individuals. Species discrimination by morphological characters in this genus is therefore often difficult due to transitional forms that may be referred to several species because of lack of data on intraspecific variability. The aim of this study was to evaluate the intraspecific variability of morphological characters that are most often used inAcantholaimustaxonomy, in order to distinguish those which are most informative for species differentiation. A reverse taxonomic approach was applied for initial species discrimination. Two loci, one each from small and large subunits of rRNA, were sequenced for 59Acantholaimusspecimens from two deep-sea locations. Twenty-seven Molecular Operational Taxonomic Units (MOTU) were identified, of which 12 were represented by more than one individual. These were then analysed for intraspecific variability in morphological characters. Some of the examined characters showed high intraspecific variability; specifically: length of cephalic setae; distance from anterior end to amphid; shape of anterior setae; position and arrangement of cervical setae. In the absence of genetic data, these characters should be used with caution for differential diagnoses or species discrimination. Other characters were more conservative within the same MOTU: body proportions; length of outer labial setae; amphidial diam.; appearance of lateral field; general arrangement of cervical setae; and shape of tail. These characters may be successfully used for species discrimination in the absence of molecular data.

An example of problems associated with DNA barcoding in tardigrades: a novel method for obtaining voucher specimens

Zootaxa ◽  
2011 ◽  
Vol 3104 (1) ◽  
pp. 42 ◽  
Author(s):  
MICHELE CESARI ◽  
ILARIA GIOVANNINI ◽  
ROBERTO BERTOLANI ◽  
LORENA REBECCHI
Keyword(s):  
Dna Barcoding ◽  
Dna Barcode ◽  
Intraspecific Variability ◽  
Original Description ◽  
Morphological Characters ◽  
Molecular Data ◽  
Integrative Taxonomy ◽  
Type Locality ◽  
Moss Sample ◽  
Voucher Specimens

We have in recent papers revealed that an integrative taxonomy approach helps to solve taxonomic problems in tardigrades. However, whole tardigrades are required for DNA work, which leaves no hologenophore voucher specimens with adult morphology. Using a novel methodology for the Tardigrada, we introduce the practice of collecting high quality maximum magnification light microscopy images of recently thawed animals to act as hologenophore voucher specimens of animals later used for DNA barcode sequencing. Within the framework of a DNA barcoding project on tardigrades, we collected a moss sample from the type locality of Macrobiotus terminalis Bertolani & Rebecchi, 1993 (Castelsantangelo, Central Apennines, Italy), a species of the “Macrobiotus hufelandi group”. Within the moss sample we found several animals and eggs with a morphology that corresponded to the original description of M. terminalis, while others were attributable to Macrobiotus macrocalix Bertolani & Rebecchi, 1993. In this study, molecular (cox1 mtDNA) analyses demonstrated no intraspecific variability in M. terminalis from the type locality but very large interspecific differences when compared with M. macrocalix and GenBank data for other species within the M. “hufelandi group”. There was also a large difference between our M. terminalis sequences and the GenBank data of a specimen attributed to the same species. The GenBank sequence originated from a population in the Northern Apennines, whose morphology appeared to be like that of the specimens of the locus typicus. This confirmed the importance in utilising material from the type locality for linking molecular data to the species’ morphological characters. Our paper underlines the importance of an integrative taxonomy in species diagnoses and demonstrates a scenario where morphological observations alone are not always sufficient. Lastly, this work adds reliable information to the sequence reference library that provides a useful building block for further studies on similar and related tardigrade taxa.

scholarly journals Multiple origins of deep-sea Asellota (Crustacea: Isopoda) from shallow waters revealed by molecular data

2008 ◽  
Vol 276 (1658) ◽  
pp. 799-808 ◽  
Author(s):  
Michael J Raupach ◽  
Christoph Mayer ◽  
Marina Malyutina ◽  
Johann-Wolfgang Wägele
Keyword(s):  
Shallow Water ◽  
Deep Sea ◽  
Morphological Characters ◽  
Molecular Data ◽  
Multiple Origins ◽  
Morphological Adaptations ◽  
The Family ◽  
Shallow Water Species ◽  
Water Species ◽  
Variable Group

The Asellota are a highly variable group of Isopoda with many species in freshwater and marine shallow-water environments. However, in the deep sea, they show their most impressive radiation with a broad range of astonishing morphological adaptations and bizarre body forms. Nevertheless, the evolution and phylogeny of the deep-sea Asellota are poorly known because of difficulties in scoring morphological characters. In this study, the molecular phylogeny of the Asellota is evaluated for 15 marine shallow-water species and 101 deep-sea species, using complete 18S and partial 28S rDNA gene sequences. Our molecular data support the monophyly of most deep-sea families and give evidence for a multiple colonization of the deep sea by at least four major lineages of asellote isopods. According to our molecular data, one of these lineages indicates an impressive radiation in the deep sea. Furthermore, the present study rejects the monophyly of the family Janiridae, a group of plesiomorphic shallow-water Asellota, and several shallow-water and deep-sea genera ( Acanthaspidia , Ianthopsis , Haploniscus , Echinozone , Eurycope , Munnopsurus and Syneurycope ).

scholarly journals Multivariate ratio analysis and DNA markers reveal a new Australian species and three synonymies in eucalypt-gall-associated Megastigmus (Hymenoptera: Megastigmidae)

2020 ◽  
Vol 110 (6) ◽  
pp. 709-724 ◽  
Author(s):  
Ngoc Hoan Le ◽  
Helen F. Nahrung ◽  
Jess A. T. Morgan ◽  
Simon A. Lawson
Keyword(s):  
Species Delimitation ◽  
Size Variation ◽  
First Record ◽  
Morphological Characters ◽  
Molecular Data ◽  
Species Discrimination ◽  
Ratio Analysis ◽  
Body Parts ◽  
Diagnostic Characters ◽  
Taxonomic Decision

AbstractThe genus Megastigmus Dalman, 1820 (Hymenoptera: Megastigmidae) contains potential biocontrol agents of the invasive eucalypt galling chalcid Leptocybe spp. (Hymenoptera: Eulophidae), with several species reported in various parts of the world. Species discrimination is challenging due to intraspecific morphological variation, difficulty in measuring sizes of body parts, and the lack of information regarding the global distribution of parasitic Megastigmus. We used two species commonly associated with Leptocybe in its native range to review taxonomic methods and determine the most reliable morphological characters in species delimitation. We examined size variation of body characters, and conducted species discrimination using multivariate ratio analysis, mitochondrial Cytochrome c oxidase subunit 1 (COI) and nuclear 28S rDNA (28S) sequences. Morphological traits were effective in species delimitation yet revealed high variation in several characters employed in current keys. Knowledge generated on morphology and DNA justified the description of a new species, M. manonae, sp. n., the first record of M. pretorianensis in Australia, and revised diagnostic characters for M. zvimendeli. Based on these diagnostic characters and molecular data, we synonymize three species (M. judikingae, syn. n., from Australia, M. sichuanensis, syn. n., from China and M. icipeensis, syn. n., from Kenya) with M. zvimendeli. Our findings highlight the importance of molecular markers in assisting taxonomic decision-making and the need for coordinated work in identifying Megastigmus associated with Leptocybe spp.

Leptoecia midatlantica, a new species of the deep-sea quill-worms (Polychaeta: Onuphidae: Hyalinoeciinae) from the Mid-Atlantic Ridge

Zootaxa ◽  
2012 ◽  
Vol 3176 (1) ◽  
pp. 45 ◽  
Author(s):  
NATALIYA BUDAEVA
Keyword(s):  
New Species ◽  
Deep Sea ◽  
Intraspecific Variability ◽  
Morphological Characters ◽  
Mid Atlantic Ridge ◽  
A New Species

A new species of the genus Leptoecia Chamberlin, 1919, collected from the northern part of the Mid-Atlantic ridge at depths around 2100–2700 m, is described. Leptoecia midatlantica sp. nov., is characterized by the presence of both uni- and bidentate simple falcigers on the first pair of parapodia, presence of dorsal cirri on all chaetigers, dorsoventrally flattened organic tube, and appearance of the first subacicular hooks around chaetiger 28–39. The unusually high intraspecific variability of several morphological characters (dentition of falcigers, shape of prostomium, and number of anal cirri) in the examined material is described. A key for the seven known species of the genus Leptoecia is provided.

Description of Ektaphelenchus oleae n. sp. (Rhabditida: Ektaphelenchinae) from Iran

Nematology ◽  
2017 ◽  
Vol 19 (10) ◽  
pp. 1123-1134 ◽  
Author(s):  
Esmaeil Miraeiz ◽  
Ramin Heydari ◽  
Yaser Adeldoost ◽  
Weimin Ye
Keyword(s):  
New Species ◽  
Ribosomal Dna ◽  
Excretory Pore ◽  
Olive Tree ◽  
Morphological Characters ◽  
Molecular Data ◽  
Northern Iran ◽  
Lateral Field ◽  
Golestan Province ◽  
Morphological And Molecular Data

Ektaphelenchus oleaen. sp. is described and illustrated based on morphological and molecular data from the rhizosphere of an olive tree (Olea europium) from the suburbs of Gorgan, Golestan Province, in northern Iran. The new species is characterised by females 441-652 μm long, stylet 15-19 μm long with wide lumen without basal swelling, labial region set off by a clear constriction, appearing bowl-like, four incisures in lateral field, excretory pore always located posterior to median bulb and anterior to hemizonid, post-uterine sac 43-73 μm long, conoid tail, and the presence of four pairs of male subventral caudal papillae. The new species is typologically similar to species belonging to three genera:Anomyctus,EktaphelenchusandSeinura, by a combination of morphological characters,e.g., head with expanded lips, forming a small bowl-like structure, stylet without knobs or swellings at the base, short conical tail and a vestigial anus and rectum in most individuals. Molecular analysis of the new species was performed using sequences of SSU and LSU ribosomal DNA genes.

scholarly journals Multi-locus phylogenetic analysis of lophiostomatoid fungi motivates a broad concept of Lophiostoma and reveals nine new species

2021 ◽  
Author(s):  
M. Andreasen ◽  
I. Skrede ◽  
W.M. Jaklitsch ◽  
H. Voglmayr ◽  
B. Nordén
Keyword(s):  
New Species ◽  
Dna Sequences ◽  
Morphological Traits ◽  
Sequence Data ◽  
Intraspecific Variability ◽  
Morphological Characters ◽  
Molecular Data ◽  
Data Matrix ◽  
Multigene Analysis ◽  
Broad Concept

Recent studies on the fungal families Lophiostomataceae and Lophiotremataceae (Pleosporales) have provided varying phylogenetic and taxonomic results concerning constituent genera and species. By adding DNA sequences of 24 new strains of Lophiostomataceae and nine new strains of Lophiotremataceae to a sequence data matrix from international databases, we provide a new understanding of the relationships within these families. Multigene analysis of the four molecular markers ITS, LSU, TEF1-α, and RPB2 reveals that the genera within Lophiotremataceae are phylogenetically well supported. Lophiostoma myriocarpum is recognised as a species of Lophiotrema in contrast to earlier concepts. In Lophiostomataceae, we resurrect a broad generic concept of the genus Lophiostoma and reduce 14 genera to synonymy: Alpestrisphaeria, Biappendiculispora, Capulatispora, Coelodictyosporium, Guttulispora, Lophiohelichrysum, Lophiopoacea, Neopaucispora, Neotrematosphaeria, Platystomum, Pseudocapulatispora, Pseudolophiostoma, Pseudoplatystomum, and Sigarispora. Nine new species are described based on molecular data and in most cases supported by morphological characters: Antealophiotrema populicola, Atrocalyx nordicus, Lophiostoma carpini, Lophiostoma dictyosporium, Lophiostoma erumpens, Lophiostoma fusisporum, Lophiostoma jotunheimenense, Lophiostoma plantaginis, and Lophiostoma submuriforme. Lophiostoma caespitosum and Lophiotrema myriocarpum are lecto- and epitypified to stabilise their species concepts. High intraspecific variability of several morphological traits is common within Lophiostomataceae.

New characters for species discrimination within the genus Prolagus (Ochotonidae, Lagomorpha, Mammalia)

2009 ◽  
Vol 83 (1) ◽  
pp. 80-88 ◽  
Author(s):  
Chiara Angelone ◽  
Carmen Sesé
Keyword(s):  
Relative Length ◽  
Intraspecific Variability ◽  
Morphological Characters ◽  
Sympatric Species ◽  
Species Discrimination ◽  
Northern Spain ◽  
Taxonomic Assignment ◽  
Late Middle Miocene ◽  
Western Asia ◽  
Dental Measurements

The genus Prolagus is very common in the Neogene and Quaternary of Europe, western Asia and northern Africa. However, the complexity of its systematics, mainly based on p3 characters that show great inter- and intraspecific variability, led to an under-utilization of Prolagus in biochronology and palaeogeography studies. A re-analysis of the species of Prolagus recorded in the Escobosa de Calatañazor karst fissure fillings (Duero Basin, northern Spain, MN7/8, late Middle Miocene) includes the introduction of new maxillary and mandibular morphological characters (position, shape and size of premolar and mandibular foramina) and new dental measurements (hypoflexus depth, distal hypercone length, and partial width of upper premolars; relative length of trigonid of lower molariform teeth) to be used for species discrimination within the genus Prolagus. The new morphological characters and measurements introduced in this paper allow for a more accurate taxonomic assignment of Prolagus species, thus improving the estimation of faunal palaeodiversity, detection of sympatric species and taphonomic mixing, and contributing to more reliable biochronological, palaeogeographical, and phylogenetic inferences based on Prolagus.

scholarly journals Under an integrative taxonomic approach: the description of a new species of the genus Loxosceles (Araneae, Sicariidae) from Mexico City

ZooKeys ◽  
2019 ◽  
Vol 892 ◽  
pp. 93-133 ◽  
Author(s):  
Alejandro Valdez-Mondragón ◽  
Claudia I. Navarro-Rodríguez ◽  
Karen P. Solís-Catalán ◽  
Mayra R. Cortez-Roldán ◽  
Alma R. Juárez-Sánchez
Keyword(s):  
New Species ◽  
Mexico City ◽  
Molecular Species ◽  
Species Delimitation ◽  
Morphological Characters ◽  
Molecular Data ◽  
Integrative Taxonomy ◽  
Taxonomic Approach ◽  
Unique Species ◽  
A New Species

A new species of the spider genus Loxosceles Heineken & Lowe, 1832, Loxosceles tenochtitlan Valdez-Mondragón & Navarro-Rodríguez, sp. nov., is described based on adult male and female specimens from the states of Mexico City, Estado de Mexico and Tlaxcala. Integrative taxonomy including traditional morphology, geometric and lineal morphology, and molecules (DNA barcodes of cytochrome c oxidase subunit 1 (CO1) and internal transcribed spacer 2 (ITS2)), were used as evidence to delimit the new species. Four methods were used for molecular analyses and species delimitation: 1) corrected p-distances under neighbor joining (NJ), 2) automatic barcode gap discovery (ABGD), 3) general mixed yule coalescent model (GMYC), and 4) poisson tree processes (bPTP). All molecular methods, traditional, geometric and lineal morphology were consistent in delimiting and recognizing the new species. Loxosceles tenochtitlansp. nov. is closely related to L. misteca based on molecular data. Although both species are morphologically similar, the average p-distance from CO1 data was 13.8% and 4.2% for ITS2 data. The molecular species delimitation methods recovered well-supported monophyletic clusters for samples of L. tenochtitlansp. nov. from Mexico City + Tlaxcala and for samples of L. misteca from Guerrero. Loxosceles tenochtitlansp. nov. is considered a unique species for three reasons: (1) it can be distinguished by morphological characters (genitalic and somatic); (2) the four different molecular species delimitation methods were congruent to separate both species; and (3) there is variation in leg I length of males between both species, with the males of L. misteca having longer legs than males of L. tenochtitlansp. nov., also morphometrically, the shape of tibiae of the palp between males of both species is different.

scholarly journals Diversity of Common Bean Landraces Collected in the Western and Eastern Carpatien

2011 ◽  
Vol 39 (No. 3) ◽  
pp. 73-83 ◽  
Author(s):  
O. Horňáková ◽  
M. Závodná ◽  
M. Žáková ◽  
J. Kraic ◽  
F. Debre
Keyword(s):  
Cluster Analysis ◽  
Common Bean ◽  
Morphological Characters ◽  
Molecular Data ◽  
Seed Traits ◽  
Phaseolus Vulgaris L ◽  
Growth Type ◽  
Banding Patterns ◽  
Polymorphism Detection ◽  
Thousand Seed Weight

The study of diversity in common bean was based on morphological and agronomical characteristics, differentiation of collected accessions by morphological and molecular markers, detection of genetic variation, and duplicates detection in bean landraces. The analysed 82 accessions of common bean (Phaseolus vulgaris L.) were collected in the Western andEastern Carpatien as landrace mixtures. Their seeds were segregated and pooled according to their characteristics; they were further multiplicated, and introduced into the collection. An extensive variation in plant and seed traits was discovered in thirty-three morphological and agronomical characteristics. Nevertheless, some of the accessions were identical in these characteristics. Cluster analysis grouped genotypes into two main branches, reflecting the growth type, seed size parameters, and thousand-seed weight. Molecular differentiation studies were performed by multilocus polymorphism detection in microsatellite and minisatellite DNA regions. Cluster analysis based on molecular data also grouped genotypes but no linkage to morphological traits was revealed. Bean accessions with very similar or identical morphological characters were clearly distinguished by DNA banding patterns. The presence of duplicates was excluded.  

scholarly journals Relicts from Glacial Times: The Ground Beetle Pterostichus adstrictus Eschscholtz, 1823 (Coleoptera: Carabidae) in the Austrian Alps

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 84
Author(s):  
Wolfgang Paill ◽  
Stephan Koblmüller ◽  
Thomas Friess ◽  
Barbara-Amina Gereben-Krenn ◽  
Christian Mairhuber ◽  
...  
Keyword(s):  
Ground Beetle ◽  
Distribution Patterns ◽  
Morphological Characters ◽  
Molecular Data ◽  
Ice Age ◽  
Dispersal Ability ◽  
Austrian Alps ◽  
Alpine Regions ◽  
Extant Species ◽  
Limited Dispersal

The last ice age considerably influenced distribution patterns of extant species of plants and animals, with some of them now inhabiting disjunct areas in the subarctic/arctic and alpine regions. This arctic-alpine distribution is characteristic for many cold-adapted species with a limited dispersal ability and can be found in many invertebrate taxa, including ground beetles. The ground beetle Pterostichus adstrictus Eschscholtz, 1823 of the subgenus Bothriopterus was previously known to have a holarctic-circumpolar distribution, in Europe reaching its southern borders in Wales and southern Scandinavia. Here, we report the first findings of this species from the Austrian Ötztal Alps, representing also the southernmost edge of its currently known distribution, confirmed by the comparison of morphological characters to other Bothriopterus species and DNA barcoding data. Molecular data revealed a separation of the Austrian and Finish specimens with limited to no gene flow at all. Furthermore, we present the first data on habitat preference and seasonality of P. adstrictus in the Austrian Alps.

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