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A. The morphology of the first gill-arch of the carnivorous fish Lethrinus nebulosus. B. An enlarged gill-raker.
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Samples of twenty-six different Red Sea fish species have been collected from areas near Jeddah. For studying the gross morphology of the gill rakers bucco-pharyngeal cavity have been dissected. Also, entire gutcontents; especially that of the stomach, have been examined to determine the nature of food. This is an attempt to correlate between shape...
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... row and that on the rest of rows is that the extemaljront of that rakers, except the tip, is naked. While their tips are covered with fine and needle shape spinules. On the other hand, rakers on the other rows are totally covered with these spinules, which are numerous on the tip. In general, raker counts per row ranges between 15 and 17 ( Fig. 27, A & B). ...
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The Itaipu Reservoir, formed in November 1982, submerged an area of 1,460 square kilometers in a-151 km extension Monthly collections from November 1983 to February 1989 were carried out in this environment with gill nets of different meshes. The aim of the research work was to evaluate the occupation process of the new environment with special reg...
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This study aimed to describe some morphological and histological aspects of the binni fish's gills. Fifteen adult male binni were pulled alive from the Al-Forat River at about (24 - 28) months, immediately after death. The gills of binni were situated on each side of the head beneath a gill cover; the operculum and the gills were made of finger-like long filaments joined to the cartilaginous gill bar. From each filament, numerous fragile lamellae that resemble leaves protrude. These lamellae comprised tiny capillaries covered in plain squamous epithelial cells. The epithelium acts as a barrier between the fish's blood and the surrounding water. The first, second, third, and fourth pairs of gill arches make up the gills supported by the bone skeleton. Each arch carries a row of gill filaments on its convex side and two rows of gill rakers on its concave side. On the rostral concave border, the filaments in the two extremes of the gill were short, but the length of all the filaments was the same. The first-gill arch's lateral rakers were longer than the medial rakers, while the fourth gill arch's medial rakers were longer than the lateral rakers. The rakers, bony comb-like projections, filled the rostral region of the gill arches at the rostral concave interior side. There was interdigitation between the gill rakers of the neighboring gill arches. Each gill arch included the lateral gill rakers pointing dorsolaterally and medial gill rakers pointing dorsomedially. Filaments originate from the gill arches and are maintained by the cartilage on the caudal convex border of the primary lamellae, from which the secondary lamellae emerge. The simple squamous epithelium lined the secondary lamellae. Keywords: Binni, Gill, Morphology, Histology
Chinese perch (Siniperca chuatsi) larvae prey on other fish species larvae at the beginning of exogenous feeding but do not eat any zooplankton in natural conditions, the mechanism behind this special feeding habit is unclear at present. This study aimed to visualize the development of gill rakers in Chinese perch larvae and observe the ingestion of larvae to different size Artemia in low salinity (5 g/L) water. Our results indicated that Chinese perch larvae demonstrated a slow development in gill rakers, larvae only had some buds from hatching to 7 days post hatching (dph), and the first and second real gill raker was observed at 9 dph and 12 dph respectively. The edar gene expression also consisted with development of gill rakers. Meanwhile, the results of ingestion showed larvae preferred to feed large size Artemia, and larvae fed the large size Artemia also had a higher npy gene expression. Compared with the larvae fed small size Artemia, the larvae which fed the large size Artemia had a higher survival rate. These data inform hypotheses development of gill rakers may influence the prey choice in Chinese perch larvae, no real gill rakers may cause the larvae can not to forage small size zooplankton at first-feeding stage and, thus, the Chinese perch larvae form the special feeding habit.
The present work examined 10 gill systems of European barracuda grossly and by scanning electron microscopy (SEM). Grossly, there were four pairs of the gill arches. The convex border of the gill arch carried the gills filaments, but there were abundance of spines near to its concave border and the gill rakers were absent. Laterally near to the convex border of the gill arch, SEM observations revealed that the first gill arch carried small elliptical, oval, cuboidal, and triangular groups of two shapes of spines; spearhead‐like spines and canine‐like spines, but the other three gill arches carried larger groups of the same shaped spines with the appearance of waterfalls. Medially near to the convex border of the first gill arch, the canine‐like spines were observed only in the form of vertical rectangular groups that adhered in some areas. Laterally near to the concave border, the two shapes of spines were present in the form of longitudinal groups separated by spaces at the first gill arch, but these spaces were absent in the other three gill arches. Medially near to the concave border of the first gill arch, the two shapes of spines were presented in oval groups, while the other three gill arches were covered entirely by cuboidal groups of the two shapes of spines. The absence of the gill rakers in conjunction with an abundance of spines helps the European barracuda to control the food particles from escaping to the gill filaments to prevent its suffocation. The European barracuda had four pairs of the gill arches. The convex border of the gill arch carried the gills filaments, but there were abundance of spines near to its concave border and the gill rakers were absent. SEM observations revealed that there were two shapes of spines; spearhead‐like spines and canine‐like spines that differed in its form of distribution near to the concave and convex borders among the four gill arches medially and laterally.
The current work gives concern to study the morphology of the Merluccius merluccius gills by using gross morphology, scanning electron microscopy (SEM), and light microscopy. The findings of the present study revealed that the gill system consisted of four pairs of gill arches which carry the gill filaments on the convex border and gill rakers on the concave border of them. SEM results revealed that the rakers and the spines distribution on the first gill arch differed from that of the other three gill arches on the lateral and medial surfaces. On the surface the gill filaments, there were longitudinal ridges that carried pores of chloride cells and mucous cells. The histological examination revealed that, the gill arch composed of hyaline cartilage that presented in the form of cups. Each cup consisted of central cartilagenous core and peripheral cartilagenous matrix. The gill filaments composed of cartilaginous bar of peripheral cartilaginous matrix and central cartilaginous core extended from the gill arches and covered by an epithelial layers with a few mucous cells permeate it, and chloride cells were straggly in the interlamellar epithelium. Each gill filament carried several leaves like secondary lamellae on both sides of it. The epithelium, which lined the secondary lamellae, composed of epithelial pavement cells, some mucous cells, and pillar cells.
In the present study, we focused on the morphology of L. sceleratus gills using gross anatomy, scanning electron microscopy as well as light microscopy. Results of this study revealed that the gill openings appeared as simple slits anterior to the pectoral fin without distinct opercular cover. The gill system consisted of three pairs of gill arches carrying two rows of gill rakers on its concave border and gill filaments on its convex border. SEM showed that all surfaces of the gill arch were characterized by the presence of the longitudinal ridges with many taste buds in addition to many spines around the rakers. Histologically, the gill arch was composed of curved bar of hyaline cartilage with slightly elevated area corresponding to the sites of gill rakers. Each filament was formed of a thin central cartilaginous core surrounded by peripheral cartilaginous ma trix and covered by primary epithelial layer with abundant mucous cells. The chloride cells appeared mainly near to the base of secondary lamellae. Each gill filament gave rise to a very large number of secondary lamellae on both sides. The epithelial lining of the secondary lamellae comprised epithelial pavement cells, few mucous cells and pillar cells. The latter interposed the enriched blood capillaries. These findings suggest that L. sceleratus gills have characteristic morphological features that are related to adaptive functions for feeding habits, osmoregulation and respiratory mechanism with in their living environment.
Morphological and genetic studies of mormyrid fishes belonging to the genus Marcusenius from South Africa and Mozambique revealed four species of which three are described as new. Marcusenius pongolensis is widespread throughout the Incomati, Pongola and Kosi river systems, and sparsely represented in the Limpopo River system in South Africa. Marcusenius krameri sp. nov. is endemic to the Limpopo River system, and is the sister taxon of M. caudisquamatus sp. nov. from the Nseleni and Mhlatuze river systems in the KwaZulu-Natal Province of South Africa. The Ruvuma specimens were well differentiated from all southern and eastern African species of Marcusenius, and are therefore recognised as M. lucombesi sp. nov. Phylogenetic analysis of the mitochondrial cytochrome b gene showed that the three new species and M. altisambesi form a monophyletic lineage that is sister to a group containing M. pongolensis and M. macrolepidotus. Marcusenius krameri and M. lucombesi seems to prefer slow flowing reaches of rivers, whereas M. pongolensis and M. caudisquamatus seems to mainly inhabit rapid flowing sections of rivers with a rocky substrate. A key to the southern African species of Marcusenius is provided.
