scholarly journals Redescription of the sea urchin Eucidaris thouarsii (Cidaroida: Cidaridae) based on material from the Mexican Pacific

2021 ◽  
Vol 69 (Suppl.1) ◽  
pp. 438-451
Author(s):  
Mariana-P. Ruiz-Nava ◽  
Carlos-A. Conejeros-Vargas ◽  
Francisco-A. Solís-Marín
Keyword(s):  
Electron Microscopy ◽  
Sea Urchin ◽  
Gulf Of California ◽  
Oceanic Islands ◽  
Mexican Pacific ◽  
Horizontal Diameter ◽  
Apical System ◽  
Well Differentiated ◽  
Scanning Electron ◽  
Test Shape

Introduction: Eucidaris thouarsii is a cidaroid sea urchin found from the Gulf of California to Ecuador. Its taxonomy is based on general descriptions of test shape, primary and secondary spines, the Aristotle’s lantern, apical system, and peristome. Objective: To redescribe E. thouarsii with detailed descriptions, adding new taxonomic characters. Methods: We examined and reidentified 792 specimens, measuring and analyzing in detail structures of taxonomic value. Results: The horizontal diameter of the test ranges from 2.8 to 48.45 mm; the peristome corresponds to 40-60 % of that diameter, proportionally bigger than the apical system; the interambulacral areas are four times larger than the ambulacral areas. The variation of the pedicellariae is shown with scanning electron microscopy. The specimens of the Mexican oceanic islands are markedly different when compared to those of the mainland. Conclusions: Eucidaris thouarsii has five well differentiated secondary spines, and also specific regionalization; the apical system varies according to the size of the Horizontal Diameter of the Test; the globiferous pedicellariae have intraspecific differences; and the tridentate pedicellariae are specifically regionalized.  

Ultrastructural Analysis of Mouthparts of Adult Horn Fly (Diptera: Muscidae) From the Brazilian Midwest Region

2020 ◽  
Vol 57 (5) ◽  
pp. 1447-1458 ◽  
Author(s):  
Fernando de Freitas Fernandes ◽  
Ana Cristina Bahia ◽  
Nágila Francinete Costa Secundino ◽  
Paulo Filemon Paolucci Pimenta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Morphological Characteristics ◽  
Sense Organs ◽  
Horn Fly ◽  
Phylogenetic Studies ◽  
Midwest Region ◽  
Well Differentiated ◽  
Maxillary Palps ◽  
Scanning Electron

Abstract The ultrastructure of the mouthparts of Haematobia irritans (L.) was investigated by scanning electron microscopy. The morphological characteristics of the maxillary palps, labium (prementum and postmentum), labrum, hypopharynx, haustellum, and labellar lobes are described, as well as of the sensilla evidenced on all the surface of the mouthparts, and the set of different positions assumed by the mouth apparatus of this fly. Based on their morphology, 12 well-differentiated sensilla were identified, among three types of cuticular sensilla: trichoidea, coeloconica, and campaniformia. A slight sexual dimorphism in the sensilla patterns found in the mouthparts of H. irritans was evidenced. These observations are discussed with reference to the current literature on the functional morphology of sense organs of Insecta. These results could facilitate the recognition of the chemosensory sensilla by electrophysiological techniques, and foment future taxonomic and phylogenetic studies to better elucidate the evolution of Diptera, Muscomorpha.

Free-living marine planktonic unarmoured dinoflagellates from the Gulf of Mexico and the Mexican Pacific

2015 ◽  
Vol 58 (1) ◽  
Author(s):  
Sergio Escobar-Morales ◽  
David U. Hernández-Becerril
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Gulf Of Mexico ◽  
Species Composition ◽  
New Records ◽  
Morphological Characters ◽  
Phylogenetic Group ◽  
Free Living ◽  
Mexican Pacific ◽  
Scanning Electron

AbstractThe so-called unarmoured dinoflagellates are not a “natural” (phylogenetic) group but they lack thecal plates, share fragility and possess relatively few morphological characters that can be positively identified. This study depicts the species composition of unarmoured dinoflagellates collected from sites along the coasts of the Gulf of Mexico and the Mexican Pacific and includes their descriptions and illustrations. We identified a total of 25 species belonging to 13 genera and six families that were studied through various techniques using light and scanning electron microscopy. Seven new records for the Mexican Pacific are annotated here that include

Nematodes from the Gulf of California. Part 1. The genera Ceramonema Cobb, 1920, Pselionema Cobb in Cobb, 1933 and Pterygonema Gerlach, 1954 (Nematoda: Ceramonematidae)

Nematology ◽  
2008 ◽  
Vol 10 (3) ◽  
pp. 347-373 ◽  
Author(s):  
Manuel Mundo-Ocampo ◽  
Irma Tandingan De Ley ◽  
Axayácatl Rocha-Olivares ◽  
James Baldwin ◽  
Oleksandr Holovachov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
New Species ◽  
Sexual Dimorphism ◽  
Gulf Of California ◽  
Potential Source ◽  
The Family ◽  
Two New Species ◽  
Morphology And Morphometry ◽  
One New Species ◽  
Scanning Electron

AbstractThe morphology and morphometry of nematodes of six species of the family Ceramonematidae is described using light and scanning electron microscopy. In this paper, we describe two new species and redescribe two known species of Ceramonema and one new species each of Pselionema and Pterygonema. Ceramonema altogolfi sp. n. is characterised by the 0.8-1.3 mm long body, 187-247 body annules, weakly developed zygapophyses, presence of intracuticular vacuoles, sexual dimorphism in amphid shape, presence of vaginal sclerotisation, complex gubernaculum and relatively uniform anal and cloacal annules, whilst C. inguinispina sp. n. has a 0.8-1.1 mm long body, 135-191 body annules, weakly developed zygapophyses, presence of intracuticular vacuoles, sexual dimorphism in amphid shape, absence of vaginal sclerotisation, thorn-shaped precloacal projection, plate-like gubernaculum and double cloacal annule. Pselionema psednum sp. n. is distinguished by 1.4-1.7 mm long body, 251-292 body annules, weakly developed zygapophyses, absence of intracuticular vacuoles, sexual dimorphism in amphid shape and Pterygonema mexicanum sp. n. is characterised by having amphids lacking a central thorn-like projection and pharynx with a distinct posterior glandular bulb. Populations of Ceramonema rectum and Ceramonema cf. yunfengi are also described. The male cloacal region of the species examined appears to be a rich potential source of taxonomic characters that have as yet received insufficient attention for this family.

Xyala finneyae sp. n. (Nematoda: Xyalidae) from the intertidal region of the eastern Gulf of California, Mexico

Nematology ◽  
2010 ◽  
Vol 12 (5) ◽  
pp. 673-680 ◽  
Author(s):  
Ian King ◽  
Manuel Mundo-Ocampo ◽  
Paul De Ley
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
Sexual Dimorphism ◽  
Intertidal Zone ◽  
Gulf Of California ◽  
Type Species ◽  
Optical Section ◽  
Anterior Position ◽  
Scanning Electron

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).

Fertilization Membranes and Sea Urchin Embryos Studied by Scanning Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 530-531
Author(s):  
Walter J. Humphreys ◽  
David T. Lindsay
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Sea Urchin ◽  
Structural Features ◽  
Vitelline Membrane ◽  
Cortical Granules ◽  
Freeze Dried ◽  
Fertilization Membrane ◽  
Ultrathin Sections ◽  
Scanning Electron

Scanning electron microscopy (SEM) of specimens freeze-dried after fixation in Parducz fixative and ultrathin sections of the sea urchin, Strongylocentrotus purpuratus show that the egg is covered by many papillae about 0.25μ in diameter and 0.5μ long (Fig. 1a). When the vitelline layer lifts away from the surface of the egg at the time of fertilization it has many uniformly spaced protrusions that persist as prominent and consistent structural features of the fertilization membrane, which forms when material from ruptured cortical granules is added to the inner surface of the raised vitelline membrane. Dimensions of the protrusions, their spacing on the membrane, and their projection in a direction outward from the egg (Fig. 1b) suggests that they originate when the vitelline layer lifts away from the egg surface in the form of a somewhat distorted and expanded replica of the papillae-bearing surface of the unfertilized egg.

Nematodes from the Gulf of California. Part 2. Ceramonema nasobema sp. n. (Nematoda: Ceramonematidae)

Nematology ◽  
2008 ◽  
Vol 10 (6) ◽  
pp. 835-844 ◽  
Author(s):  
Oleksandr Holovachov ◽  
Manuel Mundo-Ocampo ◽  
Irma Tandingan De Ley ◽  
Paul De Ley
Keyword(s):  
Electron Microscopy ◽  
South Africa ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
Sexual Dimorphism ◽  
Gulf Of California ◽  
Additional Data ◽  
Scanning Electron

AbstractAn 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.

Morphology and taxonomy of Dinophysis species of the section Hastata (Dinoflagellata), including the description of Dinophysis conjuncta sp. nov., from the Mexican marine waters

2013 ◽  
Vol 93 (5) ◽  
pp. 1187-1202 ◽  
Author(s):  
Karina Esqueda-Lara ◽  
Dulce Parra-Toriz ◽  
David U. Hernández-Becerril
Keyword(s):  
Electron Microscopy ◽  
New Species ◽  
Gulf Of Mexico ◽  
Gulf Of California ◽  
New Records ◽  
Full Description ◽  
Distribution Data ◽  
Marine Waters ◽  
Mexican Pacific ◽  
Southern Gulf Of Mexico

There have been recent attempts to improve our knowledge about dinoflagellates of the order Dinophysales either in Mexican marine waters or worldwide, and although new records and even new species have reliable illustrations and descriptions, this group is so diverse that it needs to be studied in more detail. This paper is the product of the analysis of net phytoplankton material collected from coasts of the tropical Mexican Pacific (Gulf of California, Central Mexican Pacific and Gulf of Tehuantepec), and the southern Gulf of Mexico. Material was studied using light microscopy and scanning electron microscopy (SEM). Eleven taxa (10 species and one variety) of the section Hastata were fully identified, with nine species studied for the first time by electron microscopy (only Dinophysis hastata and D. schuettii had been previously studied by SEM), and including seven new records for the Mexican Pacific (Dinophysis monacantha, D. nias, D. phalacromoides, D. pusilla, D. swezyae, D. uracantha var. mediterranea, and D. uracanthoides), and one new record for the Gulf of Mexico (Dinophysis uracanthoides). Two species remain as unidentified, as only one specimen of each was found. Additionally, we studied in detail the new species, Dinophysis conjuncta sp. nov., for which a full description is provided. Descriptions, measurements, illustrations and local distribution data are provided for each species.

Environmental Scanning Electron Microscopy (ESEM) Study of Sea Urchin Embryos after Deciliation with Chloral Hydrate

1998 ◽  
Vol 4 (S2) ◽  
pp. 1130-1131
Author(s):  
Heide Schatten ◽  
Amitabha Chakrabarti
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Sea Urchin ◽  
Chloral Hydrate ◽  
Sea Water ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Lytechinus Pictus ◽  
Sea Urchin Embryos ◽  
Scanning Electron

Environmental Scanning Electron Microscopy has opened up the potential to study biological events in their native occurence. While still in the early stages of exploration, the ability to view samples in their native state with the resolution provided by scanning electron microscopy is highly desirable and will provide insights in dynamic processes which previously had only been possible by interpretation with indirect methods or by static images obtained with transmission electron microscopy.In preliminary experiments to explore the potential of studying native events with the ESEM we have investigated sea urchin embryos after deciliation with chloral hydrate. The Philips XL-30 ESEM instrument was used to obtain images of lightly fixed (0.1% glutaraldehyde in sea water), lightly coated embryos that had been treated as follows. Chloral hydrate was added at a concentration of 0.1% to blastulae of Lytechinus pictus at 24 hours after fertilization. Observation with light microscopy indicates that cilia become gradually shed into the sea water within 10 to 20 hours after chloral hydrate application.

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