Cytological studies on the specific distinctness of the ovine and bovine 'Strains' of the Nematode Haemonchus Contortus (Rudolphi) cobb (NematodaL Trichostrongylidae)

1955 ◽  
Vol 3 (3) ◽  
pp. 312 ◽  
Author(s):  
KC Bremner
Keyword(s):  
Chromosome Number ◽  
Host Specificity ◽  
Haemonchus Contortus ◽  
Distinct Species ◽  
Breeding Experiment ◽  
Separate Species ◽  
X Chromosomes ◽  
Cross Breeding ◽  
Mixed Infestation

The studies reported here follow the conclusions of Roberts, Turner, and McKevett (1954) that the ovine and bovine "strains" of Haemonchus contortus (Rudolphi 1803) Cobb 1898 are distinct species. The cytology of the two forms has been investigated and it was found that the chromosome number for each form was 2n = 11 (B), 12 (@). The autosomes of each form measure 3� in length and, whereas the X-chromosomes of the worms from sheep are similar in size to the autosomes, the X-chromsomes of the worms from cattle attain a size of 8�. Fertile hybrid females were obtained in a cross-breeding experiment and were also seen in a natural, mixed infestation. These, however, appeared in only small numbers and, furthermore, as they were never seen in animals with pure infestations as judged by the type of larva, it seemed evident that some fertility barrier is present. Some discussion is given to the host specificity of the two forms and further evidence is brought forward to support previous conclusions that some degree of host specificity is present. It is concluded that the restricted degree of interbreeding encountered, together with considerations of host specificity, support the claims of Roberts, Turner, and McKevett (1954) that the two forms are separate species.

A Morphological Comparison of the Adults of Oryzaephilus surinamensis (L.) and O. mercator (Fauv.) (Col., Cucujidae).

1958 ◽  
Vol 49 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Joan M. Slow
Keyword(s):  
Male Genitalia ◽  
The Other ◽  
Oryzaephilus Surinamensis ◽  
Breeding Experiment ◽  
Morphological Comparison ◽  
Separate Species ◽  
Cross Breeding ◽  
Clear Cut ◽  
The Status

The object of the work described in this paper was to compare adults of Oryzaephilus surinamensis (L.) and O. mercator (Fauv.) by morphological and biometric methods with a view to determining the status of the latter as either a variety of O. surinamensis or as a separate species.There are some marked and constant differences between the two insects in the structure of the male genitalia. These are listed.The analysis of the biometric results shows a clear-cut difference between the two insects in the ratio of eye length to temple length. All the other ratios considered overlap, although the means may be widely different. Some of these ratios are illustrated by histograms.A cross-breeding experiment gave no offspring from the mixed pairs.It is concluded that O. mercator is a good species which can be recognised morphologically.

Proteocephalus filicollis(Rudolphi, 1802) andProteocephalus ambiguus(Dujardin, 1845), Two Hitherto Confused Species of Cestodes

1968 ◽  
Vol 42 (3-4) ◽  
pp. 395-410 ◽  
Author(s):  
J. J. Willemse
Keyword(s):  
Host Specificity ◽  
Seasonal Cycle ◽  
Gasterosteus Aculeatus ◽  
Morphological Characteristics ◽  
Distinct Species ◽  
Morphological Data ◽  
Intermediate Hosts ◽  
Separate Species ◽  
Experimental Infections ◽  
High Degree

Several kinds of data were collected from worms belonging to the genusProteocephalus, living in the intestines ofPygosteus pungitiusandGasterosteus aculeatus.a. Morphological data. When we compare the morphological characteristics of worms from the two hosts we find small differences in those characteristics commonly used in the descriptions of species of the genusProteocephalus. Regularly differences of the same magnitude are used to separate species.b. Experimental infections show that a high degree of host specificity exists in worms from the two hosts. It is impossible to cultivate worms originally coming from one host species in the intestine of the other. These experimental infections were carried out either by feeding intermediate hosts carrying plerocercoids to fishes free of infection, or by collecting worms from the intestine of one fish and introducing them into the intestine of another fish.Experimental infections of alien hosts failed whereas infections of the proper host, carried out as controls, always were successful.c. Mixed populations ofGasterosteusandPygosteusliving in a small closed canal system gave additional data indicating the existence of a high degree of host specificity. Throughout the yearGasterosteusshowed no infection at all whereasPygosteuswas “normally” infested.d. Monthly dissections ofPygosteusshowed that inProteocephalusliving in this fish species no seasonal cycle exists similar to that found by Hopkins inProteocephalusfromGasterosteus. The stages of development ofProteocephaluscollected during the dissections ofGasterosteuscorrespond with Hopkins' seasonal cycle.e. As a result of these observations it is proposed to consider the worms fromPygosteusas belonging to a distinct species. Since Dujardin was the first to describe worms belonging to the genusProteocephalusand living in the intestine ofPygosteusasProteocephalus ambiguus(Dujardin, 1845) this obviously ought to be the name of the species involved. The use of the nameP. filicollis(Rudolphi, 1802) is restricted to material fromGasterosteus.

Analysis of the differences between Syntormon pallipes and S. pseudospicatus (Diptera: Dolichopodidae): morphological and molecular data

2019 ◽  
Vol 28 (2) ◽  
pp. 305-316
Author(s):  
M.A. Chursina ◽  
I.Ya. Grichanov
Keyword(s):  
Dna Analysis ◽  
Distinct Species ◽  
Molecular Data ◽  
Wing Shape ◽  
Morphological Data ◽  
12S Rrna ◽  
Separate Species ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
Morphological And Molecular Data

The recent catalogues of the family Dolichopodidae considered Syntormon pallipes (Fabricius, 1794) and S. pseudospicatus Strobl, 1899 as separate species. In this study, we used three approaches to estimate the significance of differences between the two species: molecular analysis (COI and 12S rRNA sequences), analysis of leg colour characters and geometric morphometric analysis of wing shape. The morphological data confirmed the absence of significant differences between S. pallipes and S. pseudospicatus found in the DNA analysis. Significant differences in the wing shape of two species have not been revealed. Hence, according to our data, there is no reason to consider S. pseudospicatus as a distinct species.

Intercontinental differentiation in Medicago rigidula

1990 ◽  
Vol 68 (12) ◽  
pp. 2607-2613 ◽  
Author(s):  
Ernest Small ◽  
Brenda Brookes ◽  
Eric J. Crawford
Keyword(s):  
Chromosome Number ◽  
North Africa ◽  
Separate Species ◽  
Spine Morphology ◽  
Medicago Rigidula

European and Asian plants assignable to Medicago rigidula (L.) All., as this species is currently interpreted, were found to differ morphologically. Indeed, a combination of morphological, geographical, and interbreeding evidence supports the recognition of the European and Asian plants presently interpreted as M. rigidula as separate species. The best characters for distinguishing plants of the two continents are number of pollen pores (pollen consistently 3-pored in European plants, and consistently 4-pored in Asian plants), number of coils in the pod (averaging 4.5 in European plants, 5.5 in Asian), and fruit spine morphology (usually more hooked and longer in European compared to Asian plants). Plants of North Africa require further study, but the specimens examined were generally closer to European than to Asian plants. The chromosome number of 28 Asian collections, 24 European collections, and 3 African collections was constant, with n = 7.

scholarly journals Influences of oceanic islands and the Pleistocene on the biogeography and evolution of two groups of Australasian parrots (Aves: Psittaciformes: Eclectus roratus, Trichoglossus haematodus complex). Rapid evolution and implications for taxonomy and conservation

2016 ◽  
Vol 3 (2) ◽  
pp. 47-66
Author(s):  
Michael P. Braun ◽  
Matthias Reinschmidt ◽  
Thomas Datzmann ◽  
David Waugh ◽  
Rafael Zamora ◽  
...  
Keyword(s):  
Species Complex ◽  
Rapid Evolution ◽  
New Guinea ◽  
Distinct Species ◽  
Genetic Evidence ◽  
Valid Species ◽  
Separate Species ◽  
Species Complexes ◽  
Mitochondrial Cytochrome B ◽  
Avian Diversification

AbstractThe Australasian region is a centre of biodiversity and endemism, mainly based on the tropical climate in combination with the large amount of islands. During the Pleistocene, islands of the Sahul Shelf (Australia, New Guinea, Aru Islands) had been part of the same land mass, while islands within the Wallacea (Lesser Sunda Islands, Moluccas, Sulawesi etc.) remained isolated. We investigated biogeographical avian diversification patterns of two species complexes across the Wallacea and the Sahul Shelf: the Eclectus Parrot Eclectus roratus Wagler, 1832, and the Rainbow Lorikeet Trichoglossus haematodus Linnaeus, 1771. Both species are represented by a large number of described geographical subspecies. We used mitochondrial cytochrome b (cyt b) sequences for phylogenetic and network analysis to detect biogeographic roles of islands and avian diversification patterns. The number of threatened taxa in this region is increasing rapidly and there is an urgent need for (sub-)species conservation in this region. Our study provides first genetic evidence for treating several island taxa as distinct species. In both species complexes similar genetic patterns were detected. Genetic diversification was higher across the islands of the Wallacea than across the islands of the Sahul Shelf. Divergence in E. roratus can be dated back about 1.38 million years ago, whereas in the younger T. haematodus it was 0.80 million years ago. Long distance dispersal was the most likely event for distribution patterns across the Wallacea and Sahul Shelf. The geographic origin of the species-complex Eclectus roratus spp. is supposed to be Wallacean, but for the species-complex Trichoglossus haematodus spp. it is supposed to be non-Wallacean. Trichoglossus euteles, so far considered a distinct species, clearly belongs to the Trichoglossus-haematodus-complex. The only case of sympatry in the complex is the distribution of T. (h.) euteles and T. h. capistratus on Timor, which means a rapid evolution from one ancestor into two distinct species within only 800,000 years. For all other taxa a Checkerboard distribution pattern is present. In this complex, 8 taxa are already treated as separate species (del Hoyo et al. 2014). Based on genetic evidence, the following populations are supported to represent phylogenetic units: (1) N New Guinea (haematodus) incl. Biak (rosenbergii), Bismarck Archipelago (massena), and New Caledonia (deplanchii); (2) Flores (weberi); (3) E Australia (moluccanus) incl. Aru Islands (nigrogularis) and S New Guinea (caeruleiceps); (4) N Australia (rubritorquis); (5) Timor 1st lineage (capistratus) incl. Sumba (fortis); (6) Bali and Lombok (mitchellii); (7) Sumbawa (forsteni); (8) Timor 2nd lineage (euteles). Those 8 phylogenetic units are not identical to the 8 species listed by del Hoyo et al. (2014). Several populations on smaller islands are under decline, a separate species status may lead to a higher conservation status in both species complexes, which are currently listed as “Least Concern”. Eclectus roratus is currently treated as monospecific. Based on genetic evidence, the following populations are suggested being treated as valid species: (1) Sumba (Eclectus cornelia), (2) Tanimbar Islands (E. riedeli), (3) Moluccas (E. roratus), and (4) New Guinea (E. polychloros incl. Aru Islands (E. aruensis), and Solomon Island (E. solomonensis).

Mitochondrial DNA sequence evidence supporting the recognition of a new North Atlantic Pseudostichopus species (Echinodermata: Holothuroidea)

2004 ◽  
Vol 84 (5) ◽  
pp. 1077-1084 ◽  
Author(s):  
Francisco A. Solís-Marín ◽  
David S.M. Billett ◽  
Joanne Preston ◽  
Alex D. Rogers
Keyword(s):  
Dna Sequences ◽  
Mitochondrial Gene ◽  
Distinct Species ◽  
Molecular Study ◽  
Morphological Characters ◽  
Coi Gene ◽  
Species Status ◽  
Separate Species ◽  
The Family ◽  
A New Species

A new species of the synallactid sea cucumber genus Pseudostichopus is described, P. aemulatus sp. nov., based on genetic (DNA sequences of the mitochondrial gene Cytochrome Oxidase I [COI] gene) and morphological characters. A comparative molecular study with two other species of the same genus (P. villosus and P. mollis) and from a different family (Isostichopus fuscus) was carried out in order to clarify its taxonomic identity. The nucleotide distance between P. aemulatus sp. nov. and P. villosus and P. mollis is sufficient to support distinct species status. The estimated difference in the number of amino acids, coded for by a partially sequenced COI gene, within the species of the family Synallactidae ranged from 4 to 18. The phylogenetic analysis clearly supports separate species status of these sympatric morphotypes, as indicated by the morphological analysis.

The Dogma of Dingoes—Taxonomic status of the dingo: A reply to Smith et al.

Zootaxa ◽  
2019 ◽  
Vol 4564 (1) ◽  
pp. 198 ◽  
Author(s):  
STEPHEN M. JACKSON ◽  
PETER J.S. FLEMING ◽  
MARK D.B. ELDRIDGE ◽  
SANDY INGLEBY ◽  
TIM FLANNERY ◽  
...  
Keyword(s):  
Taxonomic Status ◽  
Distinct Species ◽  
Domestic Dogs ◽  
Current Evidence ◽  
Morphological Evidence ◽  
Evolutionary Divergence ◽  
Gray Wolf ◽  
Separate Species ◽  
Gray Wolves ◽  
Narrow Scope

Adopting the name Canis dingo for the Dingo to explicitly denote a species-level taxon separate from other canids was suggested by Crowther et al.  (2014) as a means to eliminate taxonomic instability and contention. However, Jackson et al.  (2017), using standard taxonomic and nomenclatural approaches and principles, called instead for continued use of the nomen C. familiaris for all domestic dogs and their derivatives, including the Dingo. (This name, C. familiaris, is applied to all dogs that derive from the domesticated version of the Gray Wolf, Canis lupus, based on nomenclatural convention.) The primary reasons for this call by Jackson et al.  (2017) were: (1) a lack of evidence to show that recognizing multiple species amongst the dog, including the Dingo and New Guinea Singing Dog, was necessary taxonomically, and (2) the principle of nomenclatural priority (the name familiaris Linnaeus, 1758, antedates dingo Meyer, 1793). Overwhelming current evidence from archaeology and genomics indicates that the Dingo is of recent origin in Australia and shares immediate ancestry with other domestic dogs as evidenced by patterns of genetic and morphological variation. Accordingly, for Smith et al.  (2019) to recognise Canis dingo as a distinct species, the onus was on them to overturn current interpretations of available archaeological, genomic, and morphological datasets and instead show that Dingoes have a deeply divergent evolutionary history that distinguishes them from other named forms of Canis (including C. lupus and its domesticated version, C. familiaris). A recent paper by Koepfli et al.  (2015) demonstrates exactly how this can be done in a compelling way within the genus Canis—by demonstrating deep evolutionary divergence between taxa, on the order of hundreds of thousands of years, using data from multiple genetic systems. Smith et al.  (2019) have not done this; instead they have misrepresented the content and conclusions of Jackson et al.  (2017), and contributed extraneous arguments that are not relevant to taxonomic decisions. Here we dissect Smith et al.  (2019), identifying misrepresentations, to show that ecological, behavioural and morphological evidence is insufficient to recognise Dingoes as a separate species from other domestic dogs. We reiterate: the correct binomial name for the taxon derived from Gray Wolves (C. lupus) by passive and active domestication, including Dingoes and other domestic dogs, is Canis familiaris. We are strongly sympathetic to arguments about the historical, ecological, cultural, or other significance of the Dingo, but these are issues that will have to be considered outside of the more narrow scope of taxonomy and nomenclature. 

Case of mistaken identity: resolving the taxonomy between Trioza eugeniae Froggatt and T. adventicia Tuthill (Psylloidea: Triozidae)

2019 ◽  
Vol 110 (3) ◽  
pp. 340-351 ◽  
Author(s):  
Gary S. Taylor ◽  
Francesco Martoni
Keyword(s):  
Biological Control ◽  
Control Program ◽  
Distinct Species ◽  
Type Specimens ◽  
Separate Species ◽  
Mistaken Identity ◽  
South Wales ◽  
The Usa ◽  
History Of ◽  
Native And Introduced Ranges

AbstractThe ‘Eugenia psyllid’ or ‘Lilly pilly psyllid’, widely recognized in Australia and in the USA as Trioza eugeniae Froggatt (Hemiptera: Triozidae), is not T. eugeniae, but rather T. adventicia Tuthill. In this study we assessed morphological comparisons of materials from throughout the native and introduced ranges and re-examined original descriptions of both taxa, together with Froggatt's type specimens of T. eugeniae. Furthermore, through DNA barcoding analyses, we confirmed the validity of both T. adventicia and T. eugeniae as separate species. We re-described both species to include additional characters not previously included and designated a lectotype for T. eugeniae. T. eugeniae has smaller fore wings that are slightly more elongate. These lack infuscation around veins R and R1, vein Rs is relatively longer, meeting the costa closer to the wing apex; with certain veins bearing long, fine divergent setae, a character not previously described. It has consistently three inner and one outer metatibial spurs. The male parameres appear narrowly pyriform with a weak dorsolateral lobe and weakly sclerotized apices. T. adventicia has larger fore wings that are slightly more ovate with dark infuscation around veins R and R1; vein Rs is relatively shorter, meeting the costa further from the wing apex, with veins lacking long, fine divergent setae. The usual configuration of two inner and one outer metatibial spurs, previously used to separate the two species, appears inconsistent. The male parameres appear a little more broadly pyriform with slightly more sclerotized apices. T. eugeniae refers to a distinct species which has a restricted distribution only in its native range in southern subcoastal New South Wales, Australia. T. adventicia refers to a separate species, with a natural distribution in eastern subcoastal Australia, but has been introduced widely in southern Australia, to New Zealand and the USA. This study elucidates a long history of misidentification of T. eugeniae in the nursery industry and in almost 30 years of literature on its biological control in the USA. Regardless, the biological control program, unknowingly, targeted the correct species of psyllid, T. adventicia, in its foreign exploration and importation of the appropriate parasitoid as a biocontrol agent in the USA. Despite being firmly entrenched in both the nursery trade and scientific literature, the name T. eugeniae is misapplied. While the acceptance of the valid name, T. adventicia, might be regarded as both problematic and protracted, this is the correct taxonomical attribution.

scholarly journals Comparison of Colletotrichum orbiculare and Several Allied Colletotrichum spp. for mtDNA RFLPs, Intron RFLP and Sequence Variation, Vegetative Compatibility, and Host Specificity

2007 ◽  
Vol 97 (10) ◽  
pp. 1305-1314 ◽  
Author(s):  
B. Liu ◽  
L. A. Wasilwa ◽  
T. E. Morelock ◽  
N. R. O'Neill ◽  
J. C. Correll
Keyword(s):  
Host Specificity ◽  
Restriction Fragment ◽  
Fragment Length ◽  
Species Complex ◽  
Sequence Variation ◽  
Distinct Species ◽  
Vegetative Compatibility ◽  
Haplotype A ◽  
Restriction Fragment Length ◽  
Mtdna Haplotype

Based on spore morphology, appressorium development, sequence similarities of the rDNA, and similarities in amplified restriction fragment length polymorphism (AFLP), it has been proposed that Colletotrichum orbiculare, C. trifolii, C. lindemuthianum, and C. malvarum represent a single phylogenetic species, C. orbiculare. In the current study, the phylogenetic relationship among isolates in the C. orbiculare species complex was reassessed. In all, 72 isolates of C. orbiculare from cultivated cucurbit or weed hosts, C. trifolii from alfalfa, C. lindemuthianum from green bean, and C. malvarum from prickly sida (Sida spinosa) were examined for mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs), RFLPs and sequence variation of a 900-bp intron of the glutamine synthetase gene and a 200-bp intron of the glyceraldehyde-3-phosphate dehydrogenase gene, and vegetative compatibility. In addition, host specificity was examined in foliar inoculations on cucurbit, bean, and alfalfa hosts. Inoculations also were conducted on cucumber fruit. Genetically distinct isolates, based on vegetative compatibility, within the species complex (C. orbiculare, C. trifolii, and C. malvarum) had an identical mtDNA haplotype (haplotype A) when examined with each of three different restriction enzymes. Isolates of C. lindemuthianum had a very similar mtDNA haplotype to haplotype A, with a single polymorphism detected with the enzyme HaeIII. The four species represent a phylogenetically closely related group based on a statistical analysis of the 900- and 200-bp intron sequences. However, distinct RFLPs in the 900-bp intron were consistently associated with each species and could be used to qualitatively and quantitatively distinguish each species. Furthermore, each of the species showed distinct host specificity, with isolates of C. orbiculare (from cucurbits), C. lindemuthianum, and C. trifolii being pathogenic only on cucurbits, green bean, and alfalfa, respectively. Consequently, distinct and fixed nucleotide, or genotypic (intron sequences and RFLPs) and phenotypic (host specificity) characteristics can be used to distinguish C. orbiculare, C. lindemuthianum, and C. trifolii from one another; therefore, they should be recognized as distinct species. This species delineation is consistent with the most current species concepts in fungi. More isolates and further characterization is needed to determine whether C. orbiculare from cocklebur and C. malvarum represent distinct species. RFLPs of the 900-bp intron may represent a relatively inexpensive, reliable, and useful diagnostic tool for general species differentiation in the genus Colletotrichum.

Cytological studies of subterranean clover (Trifolium subterraneum L.)

1952 ◽  
Vol 3 (3) ◽  
pp. 300 ◽  
Author(s):  
JJ Yates ◽  
NH Brittan
Keyword(s):  
Chromosome Number ◽  
Somatic Chromosome ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Vicia Sativa ◽  
Somatic Chromosome Number ◽  
Separate Species ◽  
Apparent Relationship ◽  
Isolated Species

Somatic chromosome number and morphology in certain strains of subterranean clover and in species of several other fairly closely related genera have been observed. Dwalganup, Yarloop, Mt. Barker, Wenigup, Burnerang, and Red Leaf strains have each 16 fairly small chromosomes, the chromosome complexes being similar to one another and to that obtained by Wexelsen (1928) for the species. Palestine and Israel strains have each 12 large chromosomes, bearing no apparent relationship to those of the other strains but being the same in number and of a similar order of size to those found in Vicia sativa. Chromosome number and morphology may explain the failure to obtain intervarietal crosses involving Palestine, but not the low percentage of successful crosses between other strains. It is suggested that perhaps Palestine and Israel may be more correctly classed as strains of a separate species and that, with regard to their origin, Wexelsen's idea of mutational changes in isolated species offers probably the best explanation.

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