Analysis of non-morphometric morphological characters used in the taxonomy of the genus Pseudechiniscus (Tardigrada: Echiniscidae)

Author(s):  
Denis V Tumanov

Abstract Pseudechiniscus, the second-largest genus of the family Echiniscidae (Tardigrada: Heterotardigrada: Echiniscoidea), is notoriously difficult for taxonomic studies. In this study, I performed a morphological analysis of a new species from Croatia, based on a light microscopic and scanning electron microscopic examination of 45 specimens from the same sample. Furthermore, I have summarized all available data on Pseudechiniscus species, including their original descriptions, and have analysed the following complexes of morphological characters: (1) arrangement and morphology of dorsal cuticular plates, (2) ventral sculpture, (3) morphology of cephalic, trunk and leg sensory organs and (4) claw morphology. The applicability of these characters in the taxonomy and their distribution in the genus are discussed. Some of the characters traditionally used for species delimitation were shown to be unsuitable and others in need of a thorough reinvestigation. The meaning of the old term ‘faceted’, commonly used but often misapplied, has been clarified, based on the initial definition. Several characters of the claw structure were suggested as potentially useful for species delimitation. The taxonomic status of several old forms and species was discussed.

Author(s):  
Loren Anderson ◽  
Pat Pizzo ◽  
Glen Haydon

Transmission electron microscopy of replicas has long been used to study the fracture surfaces of components which fail in service. Recently, the scanning electron microscope (SEM) has gained popularity because it allows direct examination of the fracture surface. However, the somewhat lower resolution of the SEM coupled with a restriction on the sample size has served to limit the use of this instrument in investigating in-service failures. It is the intent of this paper to show that scanning electron microscopic examination of conventional negative replicas can be a convenient and reliable technique for determining mode of failure.


Phytotaxa ◽  
2018 ◽  
Vol 350 (1) ◽  
pp. 1
Author(s):  
RUI-HONG WANG ◽  
MAO-QIN XIA ◽  
JIN-BO TAN ◽  
CHUAN CHEN ◽  
XIN-JIE JIN ◽  
...  

A new species, Scrophularia jinii (Scrophulariaceae), from Central China is described and illustrated. This new species was formerly misidentified as S. fargesii, from which it differs in many morphological characters. Moreover, it is distinct with all known Scrophularia species in its unique deeply double serrate leaf margin with 3–7 big teeth on each side. Molecular phylogenetic analysis further supports its species delimitation and suggests a close relationship with several Japanese and North American species.


Zootaxa ◽  
2017 ◽  
Vol 4254 (5) ◽  
pp. 537 ◽  
Author(s):  
CHIA-HSUAN WEI ◽  
SHEN-HORN YEN

The Epicopeiidae is a small geometroid family distributed in the East Palaearctic and Oriental regions. It exhibits high morphological diversity in body size and wing shape, while their wing patterns involve in various complex mimicry rings. In the present study, we attempted to describe a new genus, and a new species from Vietnam, with comments on two assumed congeneric novel species from China and India. To address its phylogenetic affinity, we reconstructed the phylogeny of the family by using sequence data of COI, EF-1α, and 28S gene regions obtained from seven genera of Epicopeiidae with Pseudobiston pinratanai as the outgroup. We also compared the morphology of the new taxon to other epicopeiid genera to affirm its taxonomic status. The results suggest that the undescribed taxon deserve a new genus, namely Mimaporia gen. n. The species from Vietnam, Mimaporia hmong sp. n., is described as new to science. Under different tree building strategies, the new genus is the sister group of either Chatamla Moore, 1881 or Parabraxas Leech, 1897. The morphological evidence, which was not included in phylogenetic analyses, however, suggests its potential affinity with Burmeia Minet, 2003. This study also provides the first, although preliminary, molecular phylogeny of the family on which the revised systematics and interpretation of character evolution can be based. 


1993 ◽  
Vol 39 (11) ◽  
pp. 1014-1021 ◽  
Author(s):  
L. Mihailova ◽  
N. Markova ◽  
T. Radoucheva ◽  
D. Veljanov ◽  
S. Radoevska

Listeria monocytogenes 4b and its forms without cell walls (L forms of a protoplastic type) were used to study in vivo interactions with host cells. Samples of peritoneal lavage fluid were obtained from rats intraperitoneally inoculated at intervals between 1 and 15 days after challenge, for scanning electron microscopic, bacteriological, biochemical, and cytometrical investigations. Scanning electron microscopic examination revealed continuous adhesion of L forms on the macrophage surface up to 15 days after inoculation. The persistence of the L forms within the peritoneal cavity was also shown bacteriologically at all sample times, while the parental bacterial forms were isolated from the peritoneal cavity up to 7 days after challenge. The total count of peritoneal exudative cells determined by automated flow peroxidase cytometry peaked on the 15th day in animals infected with parental forms, while in animals infected with L forms the peak was lower and the macrophage population was predominant. The glycolytic and acid phosphatase activity of peritoneal exudative cells was two times higher in rats infected with L forms as compared with rats infected with the L. monocytogenes parental forms on the 3rd day after challenge. An understanding of the nature of the interactions between L forms of L. monocytogenes and peritoneal exudative cells found in vivo could be used to establish the influence of L forms on host cellular defense mechanisms.Key words: Listeria monocytogenes, L forms, peritoneal exudative cells, electron microscopy.


1982 ◽  
Vol 28 (10) ◽  
pp. 1119-1126 ◽  
Author(s):  
M. Bastide ◽  
S. Jouvert ◽  
J.-M. Bastide

The early events in the interaction of two polyene (amphotericin B and nystatin) and five imidazole (clotrimazole, ketoconazole, miconazole, isoconazole, and econazole) antimycotics used at fungicidal concentrations with the surface of Candida albicans were studied by scanning electron microscopic examination of treated intact young yeast cells, treated spheroplasts, and spheroplasts liberated from treated young yeast cells. In all cases, treatment lasted 2 h. The polyenes passed through the yeast cell wall and interacted with the cytoplasmic membrane causing the spheroplasts to lose their characteristic spheric form and to liberate their contents. Clotrimazole caused the formation of numerous circular openings in the cytoplasmic membrane, but only when the agent was used to treat spheroplasts directly. Ketoconazole, miconazole, isoconazole, and econazole interacted with the cell wall causing formation of convolutions and wrinkles. The three imidazole derivatives that are structurally closely related, miconazole, isoconazole, and econazole, inhibited the enzyme-catalyzed release of spheroplasts from young yeast cells.


Zootaxa ◽  
2012 ◽  
Vol 3192 (1) ◽  
pp. 59 ◽  
Author(s):  
BRIAN RECTOR ◽  
RADMILA U. PETANOVIĆ

A new eriophyoid mite species, Aculops orlovacae n. sp. (Acari: Prostigmata: Eriophyidae) collected from Dipsacus laciniatus L. (Dipsacaceae) in northern Serbia, is described and illustrated, including digital micrographs depicting key morphological characters. Differential diagnosis is provided in comparison with Aculops salixis Xue, Song et Hong, Aculops rhodensis (Keifer), Aculops hussongi Keifer and Aculops oblongus (Nalepa). This is the first eriophyoid mite species in the genus Aculops described from a host plant in the family Dipsacaceae and it is only the second eriophyoid known from a host species in the genus Dipsacus L. This mite was found during surveys for natural enemies of Dipsacus spp., as part of a classical biological control program.


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