Search Results

No Access

Manuel Mundo-Ocampo and James Baldwin

Abstract

The University of California Riverside Nematode Collection (UCRNC) was founded by S.A. Sher in 1953. Today it includes ca 35 000 slides and nearly 180 000 mounted specimens of nematodes from around the world, soil Tylenchida being particularly strongly represented. In addition to material mounted on slides, the collection is a repository for vials of bulked collections, scanning electron micrographs and a supporting reprint collection. The collection of name-bearing types, with more than 3200 slides, is published herein.

No Access

Christopher Chiu, James Baldwin and Manuel Mundo-Ocampo

Abstract

Metacrobeles amblyurus n. sp. (Cephalobina, Cephaloboidea) is described from sand dunes of Death Valley, California, USA. It shares with other Metacrobeles species a far posterior vulva as well as five lateral lines but is distinguished from previously known species in having a blunt (vs more tapering) conical tail. Probolae of M. amblyurus n. sp. are low conical-rounded, adjacent lips are fused into three pairs, and guard processes are lacking. The very narrow vulva in M. amblyurus n. sp. appears to be plugged in adult females, and juveniles apparently hatch exclusively within the body of the dead mother. Type localities of the two previously known species of Metacrobeles are in western Africa and this is the first confirmed report of Metacrobeles from another continent.

No Access

Paul De Ley, Ian King and Manuel Mundo-Ocampo

Abstract

Xyala finneyae sp. n. from the intertidal zone in the northern Gulf of California, Mexico, is described using light and scanning electron microscopy. The new species is characterised by the first ring of cuticular crests being at least twice as long as the crests on the remaining annules, vulva at 70-76% of body length from anterior end, sexual dimorphism in amphid fovea size with females having a smaller amphidial opening. Xyala finneyae sp. n. is most similar to the type species, X. striata, and to X. oxybiotica. It differs from the former in having the first ring of crests markedly longer than all subsequent ones, in having shorter outer labial and cephalic setae on the lip region (8-9 and 15-18 vs 12 and 22 μm, respectively), in a more anterior position of vulva (V = 70-76 vs 79-81) and in shorter spicules (29-31 vs 44-47 μm). From X. oxybiotica, it differs in the more spherical lip region with thinner cuticle on the lips (vs lips more protruding anteriad and with thicker cuticle in optical section), shorter outer labial and cephalic setae on the lip region (8-9 and 15-18 vs 13 and 23 μm, respectively), a more anterior vulva (V = 70-76 vs 81-89) and shorter spicules (29-31 vs 35 μm).

No Access

Daniel Bumbarger, James Baldwin, Manuel Mundo -Ocampo and Erik Ragsdale

Abstract

Cervidellus sonorensis n. sp. is described from sand near the roots of creosote bush (Larrea tridentata) from Anza-Borrego Desert State Park, CA, USA. It is distinguished from others in the genus by the combination of a greatly distended, guitar-shaped corpus and the morphology of the lips and labial probolae. Distinctive features include a large pharyngeal metacorpus with a double swelling, a knob-like ledge at the base of each labial probola and lips with five filamentous tines, the most apical of which are those closest to the primary axil. One male individual was discovered in this parthenogenetic species. Characters used to diagnose C. sonorensis n. sp. are not definitive with respect to other genera and are probably plesiomorphic or convergent in light of DNA-based phylogenetic hypotheses. The position of C. sonorensis n. sp. and morphologically close congeners in relation to species of Nothacrobeles and Paracrobeles is discussed.

No Access

James Baldwin, Larisa Poiras, Daniel Bumbarger and Manuel Mundo-Ocampo

Abstract

Nothacrobeles borregi n. sp. is described from blow-sand in the vicinity of the roots of creosote bush (Larrea tridentata) from Anza Borrego State Park, San Diego, California. The new species is distinctive from all others of the genus by the specific morphology of the labial probolae and lips, as viewed with both interference light and scanning electron microscopy. The probolae include a basal ridge unique by its large size, smooth rim (lacking tines), and unusual large triangular platelet projections on each side; the probolae are also distinctive in having a knob-like ledge separate and posterior to the basal ridge. Nothacrobeles borregi n. sp. provides a new insight into homology of characters important for addressing problems with generic level classification in Cephalobinae. These hypotheses of homology suggest a basis for transferring N. laticollaris n. comb. (syn. Cervidellus laticollaris). Characteristics of Nothacrobeles in relation to Cervidellus and Stegelletina are discussed.

No Access

Eyualem Abebe, Eyualem Abebe, Jyotsna Sharma, Eyualem Abebe, Jyotsna Sharma, Manuel Mundo-Ocampo, Eyualem Abebe, Jyotsna Sharma, Manuel Mundo-Ocampo and Thomas R. Platt

Examination of perianal folds of stinkpot turtles, Sternotherus odoratus, from Virginia, USA, revealed several monhysterid nematodes. The general morphological characteristics of this population, such as circular amphids, unstriated cuticle under light microscope, single outstretched ovary, single testis, caudal glands, terminal spinneret and the absence of an apophysis on the gubernaculum, with the exception of the position of the gonad in relation to the intestine, shows the affinity of this population to the Monhysteridae. Microscopic observations of the inner stoma show three (one dorsal and two ventro-sublateral) buccal wall extensions towards the lumen and numerous (ca 50) distinct denticles on its wall. Because this stoma structure is a morphological novelty within the Monhysterida and this is the first monhysterid group associated with perianal folds of turtles, we propose to establish Testudinema n. gen. within the Monhysteridae to accommodate this morphologically distinct population. We provide a detailed comparison with known monhysterid genera including those that possess a cup-shaped stoma, stoma with denticles or those genera reported to be commensals (Gammarinema, Monhystrium, Tripylium, Odontobius). Stinkpot turtles feed on benthic fauna and may acquire these commensals when the sediment is disturbed. The denticles and structure of the buccal cavity could be morphological adaptations for transition to ecto-parasitism.

No Access

Renato Inserra, Alberto Troccoli, Manuel Mundo-Ocampo, Julio Del Cid, Sergei Subbotin and James Baldwin

Abstract

Phylogenetic analysis of five gene fragments: ITS-rRNA, D2 and D3 of 28S rRNA, 18S rRNA, Hsp90 and actin, of Heterodera species and two representative Afenestrata species, A. koreana and A. orientalis, form a clade with H. cynodontis, H. bifenestra and an unidentified Heterodera sp. infecting grasses. Based on these results and the consideration that the key diagnostic characters of Afenestrata are convergent and do not define a clade, synonymisation of Afenestrata with Heterodera is proposed. The following new combinations are made: H. africana comb. n., H. axonopi comb. n., H. koreana comb. n., and H. orientalis comb. n. Furthermore, H. (= Afenestrata) sacchari is renamed as H. saccharophila nom. nov. to avoid homonymy. All these species, together with H. bamboosi, are regarded as members of a paraphyletic ‘Afenestrata group’ within Heterodera. Whilst recognised as artificial, the Afenestrata group is nevertheless an aid to discussion about these similar species. Morphological and molecular characterisation of populations of H. koreana comb. n. from Florida and H. orientalis comb. n. from Florida and Guatemala verify the identification of these populations as valid representatives for molecular studies of the species. Light and SEM observations also provide new detail and a broader understanding of the morphological range of both species. These include a longer stylet for females of H. koreana comb. n. and H. orientalis comb. n. than reported in the original descriptions. In addition, previously unreported tuberculate ridges are noted on the surface of vulval lips of H. orientalis comb. n. The lip region of second-stage juveniles of H. koreana comb. n. and H. orientalis comb. n. both include fused adjacent submedian lips that also fuse with the labial disc and the second lip annulus. The ITS-rRNA gene sequences of H. orientalis comb. n. populations from Florida and Guatemala were similar to those from the Russian type locality. Diagnostic PCR-RFLP of ITS-rRNA profiles with six enzymes for H. orientalis comb. n. and H. koreana comb. n. are given. A key for the morphological identification of species of the Afenestrata group is provided.

No Access

Oleksandr Holovachov, Manuel Mundo-Ocampo, Irma Tandingan De Ley and Paul De Ley

Abstract

An unusual new ceramonematid, Ceramonema nasobema sp. n., is described using light and scanning electron microscopy. It is particularly characterised by the presence of a perioral tube projecting 5.5-7.0 μm anterior to the lips, moderately long body (0.86-1.09 mm), relatively small number of body annules (121-134), weakly developed zygapophyses, absence of intracuticular vacuoles, pronounced sexual dimorphism in amphid shape with the male ventral amphidial branch extending as far posterior as the 55-80th annule (no extension in females), barrel-shaped stoma, sigmoid and anteriorly inclined vagina without sclerotisations, gubernaculum with dorsal apophyses and relatively uniform cloacal annules. The new species differs from all other known species of Ceramonema especially by the shape of the amphid in males, the strongly projecting perioral tube and the inclined, sigmoid, vagina. Additional data on morphology of Ceramonema algoensis (from Natal Bay, South Africa) are also provided as this species has the most prominent perioral tube among previously described members of the genus.

No Access

James G. Baldwin, Manuel Mundo-Ocampo, Ignacio Cid Del Prado Vera and Sergei A. Subbotin

Abstract

Some 134 ITS rRNA gene sequences for circumfenestrate cyst nematodes and two sequences for non-cyst nematodes of the family Heteroderidae, of which 46 were newly obtained, were analysed by phylogenetic and phylogeographic methods. Sequence and phylogenetic analysis combined with known morphological, biological and geographical data allowed the identification, amongst samples original to this study, of several belonging to known valid species as well as others that might be new species. The phylogenetic analysis revealed six major clades for circumfenestrate cyst nematodes: i) Globodera from South and North America; ii) Globodera from Europe, Asia, Africa and Oceania; iii) Paradolichodera; iv) Punctodera; v) Cactodera; and vi) Betulodera. Monophylies of Punctodera, Cactodera and Betulodera were highly supported. The Betulodera clade occupied a basal position on all trees. Phylogeographic analysis suggested a North American origin of Punctoderinae with possible further long distance dispersal to South America, Africa and other regions. Molecular data supported synonymisation of G. achilleae with G. millefolii and of G. hypolysi with G. artemisiae. PCR-RFLP diagnostic profiles for some Globodera and Cactodera species are given. Problems of diagnostics for Globodera species using PCR with specific primers are discussed.

No Access

Oleksandr Holovachov, Sven Boström, Irma Tandingan De Ley, Cymphonee Robinson, Manuel Mundo-Ocampo and Steve A. Nadler

Descriptions of three known species of Cynura, i.e., C. cerambus, C. klunderi and C. papillata, are given, including SEM micrographs of C. cerambus and a tabular compendium for all species of the genus. The phylogenetic relationships of C. klunderi are inferred from molecular data. Bayesian analyses of small subunit (SSU) of rRNA sequences support a position nested among the Plectidae suggesting the secondary simplification in the morphology of pharyngeal valvular apparatus in Cynura and the ‘return’ from a terrestrial to a marine environment in this genus.