BIOEROSION ON SPINICAUDATA SHELLS FROM A TRIASSIC FRESHWATER PALEOLAKE, MENDOZA, ARGENTINA

Palaios ◽  
2019 ◽  
Vol 34 (12) ◽  
pp. 616-630 ◽  
Author(s):  
EVELYN LUZ BUSTOS ESCALONA ◽  
ADRIANA CECILIA MANCUSO ◽  
CECILIA ANDREA BENAVENTE
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Brackish Water ◽  
Sedimentary Rocks ◽  
Aquatic Systems ◽  
Post Mortem ◽  
Preservation Potential ◽  
Binocular Microscope ◽  
Scanning Electron

ABSTRACT Bioerosion by microorganisms is termed microbioerosion. In aquatic systems, microbioerosion affects various substrates, most commonly relatively soluble ones such as sulfates, phosphates, and carbonates. However, the record of microbioerosion in fossil calcareous organisms in lake environments is limited. In northern Mendoza Province, at the locality Paramillos de Uspallata, Triassic sedimentary rocks outcrop, including the Agua de la Zorra Formation, which was deposited in a deltaic and lacustrine system. This study assesses possible bioerosion by microorganisms on spinicaudata shells from the lacustrine sequence and discusses their preservation potential in lacustrine environments. Spinicaudatans from the Agua de la Zorra Formation were analyzed under a binocular microscope and via scanning electron microscopy. Traces, the product of microbioerosion, preserved as molds, were assigned as Type 1 and 2 and were then compared with those generated by cyanobacteria, bacteria, chlorophyte, and fungi that inhabit fresh and brackish water environments. Microbioerosion occurs post-mortem and enhances dissolution of the spinicaudata shells. This, together with bias in extraction methodologies and sampling, is considered the reason for the rarity of spinicaudatans with traces of bioerosion in the lacustrine record.

scholarly journals Scanning Electron Microscopy of the Antennal Sensilla and Their Secretion Analysis in Adults of Aromia bungii (Faldermann, 1835) (Coleoptera, Cerambycidae)

Insects ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 88 ◽  
Author(s):  
Antonella Di Palma ◽  
Marco Pistillo ◽  
Raffaele Griffo ◽  
Antonio Garonna ◽  
Giacinto Germinara
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Olfactory Receptors ◽  
Mate Recognition ◽  
Gas Chromatography Mass Spectrometry ◽  
Contact Pheromone ◽  
Sensilla Basiconica ◽  
First Time ◽  
Scanning Electron

Background: It has been proved that chemical signals play an important role in mating location and reproductive behavior in cerambycids; moreover, they rely on contact chemoreception for mate recognition. Methods: Adult antennae of Aromia bungii were observed using scanning electron microscopy and adult antennal secretions were collected and analyzed with gas chromatography-mass spectrometry. Results: Twelve different types of sensilla were morphologically described on the antennae of A. bungii. At least six mechanoreceptors—one gustative, one putative chemo- or thermoreceptor, and three multiporous olfactory receptors—are present on the antennae of both sexes while a receptor-type of unclear function is limited to males. Secretions associated with sensilla basiconica were observed for the first time in a cerambycid species. Conclusions: Sensilla basiconica should play a role in odor perception detecting host tree volatiles and/or pheromones. Sensilla basiconica type 1 and 2 produce a viscous material accumulating on the antennal surface. Chemical analysis of adult antennal secretions highlighted marked differences between sexes. Some of the identified compounds have been previously reported as contact pheromone components of other cerambycid species. Our observations strongly suggest sensilla basiconica as the production sites of compounds involved in mate recognition.

Transfer of Fragilaria atomus Hust. to the genus Stauroforma (Bacillariophyta) based on observation of type and newly collected material

Phytotaxa ◽  
2014 ◽  
Vol 158 (1) ◽  
pp. 43 ◽  
Author(s):  
Dávia Talgatti ◽  
Carlos E. Wetzel ◽  
Eduardo A. Morales ◽  
Luc Ector ◽  
Lezilda Carvalho Torgan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salt Marshes ◽  
Brackish Water ◽  
Structural Features ◽  
Apical Pore ◽  
Distribution And Ecology ◽  
Scanning Electron

Fragilaria atomus was described from a brackish water lagoon in southern Finland and has subsequently been reported from several localities worldwide. However, due to its small size, it can be easily mistaken with other small, morphologically similar araphid diatoms. To clarify the morphological, metric and structural features of the species, lectotype material from BRM (Hustedt’s diatom collection) and specimens from salt marshes in Brazil were studied using light and scanning electron microscopy. Fragilaria atomus is compared to seven morphologically similar taxa belonging to Fragilaria, Stauroforma and Psammoneis. The results revealed that some important features of Fragilaria (discoid closing plates, rimoportulae and spines) are not present in F. atomus. The absence of these structures, together with the opposite striation pattern, round areolae, features of the apical pore field, and reduced or absent sternum, suggest that a transfer of F. atomus to Stauroforma is appropriate. The distribution and ecology of F. atomus is discussed.

scholarly journals Combining morphology, scanning electron microscopy, and molecular phylogeny to evaluate the taxonomic power of scales in genus Aphanius Nardo, 1827 (Teleostei: Cyprinodontidae)

2017 ◽  
Vol 25 (2) ◽  
pp. 77-87 ◽  
Author(s):  
Azad Teimori ◽  
Mina Motamedi ◽  
Mahbubeh Shaker Golmakan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Molecular Phylogeny ◽  
Brackish Water ◽  
Phylogenetic Trees ◽  
Univariate Analysis ◽  
Relative Length ◽  
Character State ◽  
Canonical Variates ◽  
Scanning Electron

AbstractScale morphology and its structural details were studied with morphometry, geometric morphometrics, and scanning electron microscopy in five IranianAphaniusspecies and examined comparatively with molecular phylogeny. Scales were cycloid and circular inA. farsicusTeimori, Esmaeili & Reichenbacher andA. vladykoviCoad, cycloid and polygonal inA. isfahanensisHrbek, Keivany & Coad andA. sophiae(Heckel), and were spined and polygonal inA. disparRüppell. Univariate analysis indicated that the relative length of anterior margin of radii played a significant role in the separation of some species studied (P < 0.05). Canonical Variates Analysis (CVA) based on seven landmarks showed clear separation between the Iranian inland and inland-relatedAphaniusspecies (IIRAS) group (four species) and the brackish water species (A. dispar). The lepidonts were conical in the IIRAS group with the exception ofA. isfahanensis(rounded) and were rounded inA. dispar. Based on the basal position of the brackish waterAphaniusspecies in the phylogenetic trees of the genusAphanius,it can be assumed that the presence of rounded lepidonts was a primary state in their scales or is the result of convergent evolution. Also, the polygonal state in the scales ofAphaniusspecies was a primitive shared character state.

Anatomy and morphology of the cornea of bovine eyes from a slaughterhouse

1995 ◽  
Vol 73 (11) ◽  
pp. 2159-2165 ◽  
Author(s):  
Michael J. Doughty ◽  
Stavros Petrou ◽  
Heather Macmillan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corneal Thickness ◽  
Good Condition ◽  
Surface Characteristics ◽  
Post Mortem ◽  
Corneal Surface ◽  
Epithelial Surface ◽  
Large Numbers ◽  
Scanning Electron

Over a 1-year period, isolated bovine eyes were obtained from a slaughterhouse and assessed within 3 h post mortem. The gross disposition (including damage or disease) and corneal surface characteristics (overall appearance and wettability) were assessed by visual inspection and light and scanning electron microscopy. The results from 315 eyes (assessed to be free of gross abnormalities or damage) showed that the corneal thickness was 1015 ± 104 μm (mean ± SD; n = 315). Measures on 100 of these eyes revealed corneal dimensions averaging 29.8 ± 1.3 mm horizontally and 23.9 ± 1.5 mm vertically. The horizontal corneal diameter was greater in eyes with thicker corneas (r = 0.917). Regardless of thickness, corneas evaluated within 3 h post mortem had a uniform thickness within ± 3% from center to edge. Histology and scanning electron microscopy revealed that even corneas subjectively assessed to be in good condition had relatively large numbers of exfoliating cells at the epithelial surface, indicating that the corneal surface of bovine eyes from the slaughterhouse is likely to be slightly compromised. Scanning electron microscopy showed the endothelium to be a mosaic of uniformly sized polygons of which 67.1 ± 2.7% were six-sided cells (hexagons).

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