The Role of Cuticular Strata Nomenclature in the Systematics of Nemata

A system of cuticular nomenclature based on the strata observed in Enoplia is proposed. Nematode cuticle is divided into four fundamental strata: epicuticle, exocuticle, mesocuticle, and endocuticle. Application of this system allows the correlation of complementary strata throughout Nemata. The major taxonomic categories within Nemata are differentiated on the basis of their cuticular strata as compared with the Enoplia model cuticle

Dictionary of Invertebrate Zoology

An exhaustive dictionary of over 13,000 terms relating to invertebrate zoology, including etymologies, word derivations and taxonomic classification. Entries cover parasitology, nematology, marine invertebrates, insects, and anatomy, biology, and reproductive processes for the following phyla: Acanthocephala Annelida Arthropoda Brachiopoda Bryozoa Chaetognatha Cnidaria Ctenophora Echinodermata Echiura Entoprocta Gastrotricha Gnathostomulida Kinorhyncha Loricifera Mesozoa Mollusca Nemata Nematomorpha Nemertea Onychophora Pentastoma Phoronida Placozoa Platyhelminthes Pogonophora Porifera Priapula Rotifera Sipuncula Tardigrada.https://digitalcommons.unl.edu/zeabook/1061/thumbnail.jp

Tribune: Genus and Family: Concepts and Natural Groupings

A little over two hundred and fifty years ago Linnaeus (= Linne) began to maneuver his concepts of animal arrangement into Aristotle’s logic of classes. Twenty-three years elapsed between the publication of his first and tenth editions of Systema naturae. The tenth edition (1758) is the acknowledged starting point of zoological nomenclature. Often forgotten but highly significant is the fact that he spent those intervening twenty years orchestrating the then known animals into the world of philosophy

A Statistical Approach to the Objective Differenciation of \u3ci\u3eHirschmanniella oryzae\u3c/i\u3e from \u3ci\u3eH. belli\u3c/i\u3e (Nemata : Pratylenchidae)

Alternate English title: A Statistical Approach to the Objective Differentiation of Hirschmanniella oryzae from H. belli (Nemata : Pratylenchidae) English language abstract: California populations attributed to Hirschmanniella belli were compared i) to paratypes of this species, ii) to topotypes of H. oryzae, and iii) to other populations of the same genus from other parts of the world. Comparisons were made using discriminant function analyses. Some small differences between California populations and paratypes of H. belli were attributed to artifacts caused by the long storage of these paratypes. Several characters were selected that were not affected by these artifacts, but were successful in differentiating a l1 California specimens (including paratypes of H. belli) from topotypes of H. oryzae. It was verified that a discriminant function analysis using these seven characters was able to separate other California specimens from Hirschmanniella specimens from other origins. The discriminant functions defined by this analysis can be used for practical identification of Hirschmanniella from California. The significance of these results for the taxonomic validity of H. belli is discussed. French language title: Une méthode statistique pour la différentiation objective de Hirschmanniella oryzae et de H. belli (Nemata : Pratylenchidae) French language abstract: Des populations californiennes attribuées à l’espèce Hirschmanniella belli ont étě comparées à : 1) des paratypes de cette même espèce; 2) des totopypes de H. oryzae; et 3) d’autres populations du même genre provenant d’autres régions du monde. Ces comparaisons ont étě faites à l’aide d’analyses discriminantes. De petites différences observées entre les populations californiennes et les paratypes de H. belli ont étě attribuées à des artefacts résultant du grand âge des paratypes. Sept caractères ont étě sélectionnés qui n’étaient pas soumis à l’action de ces artefacts mais qui réussissaient à différencier tous les spécimens californiens (y compris les paratypes de H. belli) des topotypes de H. oryzae. Il a étě vérifié qu’une analyse discriminante utilisant ces sept caractères était capable de séparer d’autres spécimens californiens de spécimens d\u27Hirschmanniella d’autres origines. Les fonctions discriminantes définies par cette analyse peuvent être employées pour l’identification pratique de Hirschmanniella californiens. La signification de ces résultats en ce qui concerne la validité de H. belli est discutée

\u3ci\u3eMeloidogyne californiensis\u3c/i\u3e n. sp. (Nemata: Meloidogyninae), Parasitic on Bulrush, \u3ci\u3eScirpus robustus\u3c/i\u3e Pursh

Meloidogyne californiensis n. sp. is described and illustrated from bulrush Scirpus robustus in California. LM and SEM studies revealed that this species differs from other known species in the genus Meloidogyne especially by the prominent posterior cuticular protuberances in the female, the distinct shape of the perineal pattern which is marked by one prominent stria in the perineum, indistinct lateral lines, many broken discontinuous striae on both sides of the arch, and the excretory pore being located posterior to stylet base. Second-stage juveniles 448-628 μm long, stylet length 11-13 μm, styler delicate, with small knobs sloping posteriorly, cephalic region with 2 or 3 annuli, and inflated rectum. Males vary greatly in size (712-1,952 μm), stylet length 18-28 μm (mean 22 μm), cephalic region slightly set off the body with two or three annuli, spear heavy with massive rounded knobs, lateral field marked by four areolated incisures as seen by SEM

The Morphometrics of \u3ci\u3eXiphinema americanum sensu lato\u3c/i\u3e in California

Ten populations of Xiphinema americanum sensu lato (S. l.)from California and two from the eastern United States were studied in a morphometric comparison. Morphometrics were generated by descriptive statistics and a stepwise discriminant analysis (SDA) from nine California field populations, and voucher specimens from a previous California vector study (Hoy, Mircetich & Lownsbery, 1984); identifed as X. californicum. AIso included were greenhouse populations of X. americanum Cobb, 1913 sensu stricto (s. s.) from New York (N.Y.) and X. rivesi Dalmasso, 1969 from Pennsylvania (Pa). SDA canonical plots of individual specimens showed the X. rivesi population to be well separated from the other populations with no overlap All other groups overlapped to varying degrees. NY X. americanum s. s., Hoy’s X. californicum, and four field populations showed close alignment, and their high degree of similarity to the neotype and the populations in a redescription of X. anzericanum s. s. (Lamberti & Golden, 1984) show that X. americanum s. s. occurs in California. Two other California populations are judged through descriptive statistics and comparison with paratypes to match the description of X. californicum. SDA fails to separate them from X . anzericanum s. s. as it did X. rivesi and in fact these two populations frequently overlap the type species. These SDA data show that X. californicum is not separable from X. americanum s. s. and is therefore considered a junior synonym of X. anzericanum s. s. French title: Morphométrie de Xiphinema americanum sensu lato en Californie French abstract: Une étude de morphométrie comparative a porté sur douze populations de Xiphinema americanum sensu lato (S. l.), dix provenant de Californie et deux de l’est des USA. Les données morphométriques ont été recueillies à partir d’une procédure statistique descriptive et d’une analyse discriminante pas-à-pas (ADP) portant sur neuf populations naturelles de Californie et des spécimens tests provenant d’une étude précédente de vection (Hoy, Mircetich & Lownsbery, 1984), l’ensemble étant identifié comme X. californicum Lamberti & Bleve-Zacheo, 1979. Sont comprises également dans cetteé tude des populations maintenues en serre de X. americanum Cobb, 1913 sensu stricto (s. s.) provenant de New York (N.Y.) et de X. rivesi Dalmasso, 1969 provenant de Pennsylvanie (Pa). Les diagrammes canoniques issus de l’ADP relatifs aux données individuelles montrent que la population de X. rivesi est bien séparée des autres populations, aucun recouvrement n’apparaissant. Tous les autres groupes montrent des recouvrements d‘importance variable. X . americanum s. s. pop. NY, X . californicum pop. Hoy et quatre populations naturelles sont en alignement étroit; leur degré élevé de similarité avec le néotype et les populations utilisées dans la redescription de X. americanum s. s. (Lamberti & Golden, 1984) démontrent que X. americanum s. s. est présent en Californie. Deux autres populations provenant de californie correspondent, d’après l’étude des paratypes et les résultats de la statistique descriptive, à X. californicum. Toutefois, I’ADP est impuissanteà les séparerd e X. americanum, à l’inverse de ceq ui est observé avec X. rivesi; en réalité les données relatives à ces deux populations recouvrent fréquemment celles de l’espèce type. Les données provenant de l’ADP montrent que X. californicum ne peut être séparé de X. americanum s. s. et par conséquent la première espèce est considérée comme un synonyme mineur de la seconde

Monophyly of clade III nematodes is not supported by phylogenetic analysis of complete mitochondrial genome sequences

<p>Abstract</p> <p>Background</p> <p>The orders Ascaridida, Oxyurida, and Spirurida represent major components of zooparasitic nematode diversity, including many species of veterinary and medical importance. Phylum-wide nematode phylogenetic hypotheses have mainly been based on nuclear rDNA sequences, but more recently complete mitochondrial (mtDNA) gene sequences have provided another source of molecular information to evaluate relationships. Although there is much agreement between nuclear rDNA and mtDNA phylogenies, relationships among certain major clades are different. In this study we report that mtDNA sequences do not support the monophyly of Ascaridida, Oxyurida and Spirurida (clade III) in contrast to results for nuclear rDNA. Results from mtDNA genomes show promise as an additional independently evolving genome for developing phylogenetic hypotheses for nematodes, although substantially increased taxon sampling is needed for enhanced comparative value with nuclear rDNA. Ultimately, topological incongruence (and congruence) between nuclear rDNA and mtDNA phylogenetic hypotheses will need to be tested relative to additional independent loci that provide appropriate levels of resolution.</p> <p>Results</p> <p>For this comparative phylogenetic study, we determined the complete mitochondrial genome sequences of three nematode species, <it>Cucullanus robustus </it>(13,972 bp) representing Ascaridida, <it>Wellcomia </it><it>siamensis </it>(14,128 bp) representing Oxyurida, and <it>Heliconema longissimum </it>(13,610 bp) representing Spirurida. These new sequences were used along with 33 published nematode mitochondrial genomes to investigate phylogenetic relationships among chromadorean orders. Phylogenetic analyses of both nucleotide and amino acid sequence datasets support the hypothesis that Ascaridida is nested within Rhabditida. The position of Oxyurida within Chromadorea varies among analyses; in most analyses this order is sister to the Ascaridida plus Rhabditida clade, with representative Spirurida forming a distinct clade, however, in one case Oxyurida is sister to Spirurida. Ascaridida, Oxyurida, and Spirurida (the sampled clade III taxa) do not form a monophyletic group based on complete mitochondrial DNA sequences. Tree topology tests revealed that constraining clade III taxa to be monophyletic, given the mtDNA datasets analyzed, was a significantly worse result.</p> <p>Conclusion</p> <p>The phylogenetic hypotheses from comparative analysis of the complete mitochondrial genome data (analysis of nucleotide and amino acid datasets, and nucleotide data excluding 3^rdpositions) indicates that nematodes representing Ascaridida, Oxyurida and Spirurida do not share an exclusive most recent common ancestor, in contrast to published results based on nuclear ribosomal DNA. Overall, mtDNA genome data provides reliable support for nematode relationships that often corroborates findings based on nuclear rDNA. It is anticipated that additional taxonomic sampling will provide a wealth of information on mitochondrial genome evolution and sequence data for developing phylogenetic hypotheses for the phylum Nematoda.</p

Comparative Morphology in Nemic Phylogeny

In 1945 Simpson wrote: Phylogeny cannot be observed. It is necessarily an inference from observations that bear on it, sometimes rather distantly, and that can usually be interpreted in more than one way. Certainly this applies to a study of nemic phylogeny where our reasoning is based upon degree of resemblance and subject to confusion by convergence and reversal. Many feel that, because fossil records are lacking, it is of little purpose to indulge in speculation on nemic phylogeny. Nemic taxonomy, however, requires such speculation when it is based upon comparative morphology. Our attempts in taxonomy are really an effort to express phylogenetic relationships. These relationships have developed through time and cannot be understood without extrapolation into the past. In presenting the modification proposed here, I have largely avoided use of zoöparasitic nemas for which a phylogeny was proposed by Dougherty in 1951. Although these are phylogenetically important, understanding the evolutionary sequence of the so-called free-living soil, freshwater, and marine nemas should be attempted first. Changes in the current concepts are necessary if the classification of the Nemata is to be consistent with the available knowledge of their comparative morphology. The modifications suggested in this paper are based upon studies of the cephalic sensory structures (setae, papillae, and amphids), esophagus (its nuclear arrangement, glands and valves), esophago-intestinal valve, excretory system, reproductive system, and total number of intestinal cells. Some use is also made of the stoma, somatic sensory structures, and cuticular specializations

System Analysis and Nematode Phylogeny

The purpose here is to suggest a method which will permit understanding of the phylogenetic relationships of contemporary representatives of the phylum Nematoda without fossils. It is not my intent to again offer a phylogeny for the Nematoda. To say that no real benefit or knowledge of phylogeny or evolution is possible without fossils is succumbing to apathy. One cannot deny or ignore that all systems, morphological, biological and chemical manifested in modern forms developed by evolutionary sequence. It is true that with a complete fossil record the rates of evolution and developmental pressures could be accurately evaluated. However, in the absence of a fossil record evolutionary relations and developmental tendencies can be assessed by the use of direct or corollary system analysis. Taxonomists must not overlook systems and their analysis