Ultrastructural focus on the oral cavity roof of the juvenile and adult white grouper (Epinephelus aeneus): Novel view of its development with carnivorous adaptation.

The present study aims to characterize the ultrastructural roof of the oral cavity roof in juvenile and adult Epinephelus aeneus using SEM. The investigation used 10 roofs of the oral cavity of juvenile and adult stages of age. The results in both age groups showed that the roof had five tooth bands, an upper valve, and a palatine region. The upper lip was divided into the anteriorly median and two lateral parts. The posterior margin of the anterior labial part is not attached to the incisive or canine teeth. The anterior surface of the canine teeth was attached to the transverse part of the upper incisive ridge that was separated from the posterior labial part by a deep groove. The semilunar upper velum showed two surfaces, two borders, and two parts. The median part of the oral surface of the velum carried the extension of the longitudinal part of the upper incisive ridge that had some variation among the two examined age stages. In addition, the median part of the oral surface of the upper velum had two rough areas located laterally on each side of the longitudinal part of the upper incisive ridge. The oral surface had several slightly elevated fungiform papillae with taste buds. The palatine region was divided into the peripheral semilunar part and the wide median part, by palatine teeth and the palatine groove laterally and by vomer teeth anteriorly. The results provided important data for the aquaculture in Egypt in relation to their diet.

Description of two new species of Ceratomyxa Thélohan, 1892 (Cnidaria: Myxosporea) infecting the gallbladder of Epinephelinae fishes from Tunisian waters using morphological and molecular data.

Ceratomyxa marginati n. sp. and C. aenei n. sp. are two new coelozoic myxosporean species infecting the gallbladder of the dusky grouper (Epinephelus marginatus) and the white grouper (Epinephelus aeneus), respectively. These two ceratomyxids were described using morphological characteristics and molecular analysis of the SSU rDNA. Ceratomyxa marginati n. sp. exhibits disporic plasmodia measuring 12-14 µm long and 11-12 µm wide and mature myxospores which are slightly crescent-shaped, measuring 6.0 ± 0.3 (5.6-6.8) µm in length and 12.9 ± 0.9 (11.5-14.0) µm in thickness. Plasmodia of C. aenei n. sp. were disporic and ellipsoidal and measured 28-32 µm in length and 19-22 µm in width. Mature myxospores of C. aenei n. sp. were elongated with unequal shell valves and measured 7.4 ± 0.6 (6.9-9.0) µm in length and 26.9 ± 2.4 (23.2-30.0) µm in thickness. Based on the SSU rDNA sequences, Ceratomyxa marginati n. sp. and C. aenei n. sp. are distinct from all other Ceratomyxa sequences available in GenBank. Phylogenetic analysis reveals that the two new species branched together within a clade with other Ceratomyxa species from different host families and different geographical localities with maximum support (100%).

Ultrastructural comparison between the oral cavity floor of the juvenile and adult Epinephelus aeneus: New vision of aging development and its carnivorous adaptation.

The current work is designed to give the first trial to characterize the ultrastructural lineaments of the oral cavity floor in juvenile and adult white grouper. The present work depends on 10 oral cavities floor from each age. The common features joined the oral cavities floor of the juvenile and adult fish summarized in; oral cavity floor had two teeth bands (lower incisive and lower molar), tongue with its two lateral spinated lines, lower velum, ridges, the lower lip divided into a single anterior part and two lateral part, and the absence of lower canine teeth. The oral surface of semilunar lower velum had round fungiform papillae that carried taste buds type I. The non-protrusible elongated tongue had a clear apex, body, and root with the absence of any taste buds. The dorsal lingual surface of the body had two lateral spinated lines, a single ridge and microtubercles. The smooth dorsal lingual surface of the root did not carry any ridges. The notched lower velum at the middle of the free border was observed in juveniles and adults. Meanwhile, there are some variations between juvenile and adult as; absence of lower incisive ridge only in juvenile, pointed tongue with sublingual ridge observed in juvenile while round without sublingual ridge in adult fish, moreover the presence of velvar ridges observed only in adult fish. The obtained findings provided essential data to aquaculture of this fish species in Egypt by determining the food particle types that are favorite to this fish. HIGHLIGHTS: The common features joined the oral cavities floor of the juvenile and adult fish summarized in; oral cavity floor had two teeth bands (lower incisive and lower molar), tongue with its two lateral spinated lines, lower velum, ridges, the lower lip divided into a single anterior part and two lateral part, and the absence of lower canine teeth. The oral surface of semilunar lower velum had round fungiform papillae that carried taste buds type I. The dorsal lingual surface of the body had two lateral spinated lines, a single ridge and microtubercles. The smooth dorsal lingual surface of the root did not carry any ridges. Meanwhile, there are some variations between juvenile and adult as; absence of lower incisive ridge only in juvenile, pointed tongue with sublingual ridge observed in juvenile while round without sublingual ridge in adult fish, moreover the presence of velvar ridges observed only in adult fish.

Age-related ultrastructural characterizations of the teeth of the white grouper (Epinephelus aeneus) in the different three age-stages.

This study represents the first attempt to describe ultrastructural features of teeth in different three ages of white grouper (Epinephelus aeneus) grossly and by the aid of the electron microscope. The current study depends on 18 oropharyngeal cavity of E. aeneus from each age-stages. There are common and special characterization between each age. Five teeth bands in the roof (incisive, canine, upper molar, palatine, and vomer), while two bands in the floor (incisive, molar). The apical teeth part resembles the arrowhead that bordered by groove distally. In 5 cm age, small upper incisive teeth had two appearance (straight and curved), and vomer teeth arranged in triangular in only one row (while, in 12 cm fish arranged in two rows and in 15 cm fish arranged in more than two rows), the palatine teeth began rostrally as one row then two rows and terminated by one row, while in other two ages began by two, then three and ended by two rows. There is no canine teeth in lower jaw in all age. In 12 cm fish, the rostral row of lower incisive teeth usually contain small straight teeth, while the posterior row mainly contain large with some medium upper incisive teeth. In 18 cm fish, upper incisive teeth located within two incisive fossa that separated from each other by longitudinal part of T-shaped upper incisive ridge and small incisive teeth had two appearance (straight and curved), and each canined teeth group contain four teeth (while in other two ages each group contain only two canine teeth).

Characterization of the complete mitochondrial genome of the white grouper Epinephelus aeneus (Perciformes, Serranidae) and a comparative analysis with other Serranidae species.

The complete mitochondrial genome of the white grouper Epinephelus aeneus, which belongs to the family Serranidae, was determined. The complete mitochondrial genome measured 16,578 bp in length and consisted of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. The mitochondrial gene arrangement of E. aeneus was typical of vertebrates. Phylogenetic analysis conducted using the mitochondrial genomes of 13 related species showed that E. aeneus clustered with other Serranidae species. This mitochondrial genome provides an important resource for addressing taxonomic issues and developing conservation strategies.

Apparently contradictory routes in the expansion of two fish species in the Eastern Atlantic.

One specimen of the boreal Clupea harengus (Clupeidae) was caught southerly, in the Gulf of Cádiz (southern Spain), whereas a specimen of the subtropical Epinephelus aeneus (Serranidae) was caught northerly, in Galician waters (north-west of Spain). These catches represent a new southernmost record in the eastern Atlantic for C. harengus and the second northernmost for E. aeneus. The co-occurrence of warm and cold affinity fishes in temperate latitudes is unusual, but the existence of anomalies in the temperature of the Atlantic waters could be behind these findings.

Construction of a microsatellites-based linkage map for the white grouper (Epinephelus aeneus).

The white grouper (Epinephelus aeneus) is a promising candidate for domestication and aquaculture due to its fast growth, excellent taste, and high market price. A linkage map is an essential framework for mapping quantitative trait loci for economic traits and the study of genome evolution. DNA of a single individual was deep-sequenced, and microsatellite markers were identified in 177 of the largest scaffolds of the sequence assembly. The success rate of developing polymorphic homologous markers was 94.9% compared with 63.1% of heterologous markers from other grouper species. Of the 12 adult mature fish present in the broodstock tank, two males and two females were identified as parents of the assigned offspring by parenthood analysis using 34 heterologous markers. A single full-sib family of 48 individuals was established for the construction of first-generation linkage maps based on genotyping data of 222 microsatellites. The markers were assigned to 24 linkage groups in accordance to the 24 chromosomal pairs. The female and male maps consisting of 203 and 202 markers spanned 1053 and 886 cM, with an average intermarker distance of 5.8 and 5.0 cM, respectively. Mapping of markers to linkage groups ends was enriched by using markers originating from scaffolds harboring telomeric repeat-containing RNA. Comparative mapping showed high synteny relationships among the white grouper, kelp grouper (E. bruneus), orange-spotted grouper (E. coioides), and Nile tilapia (Oreochromis niloticus). Thus, it would be useful to integrate the markers that were developed for different groupers, depending on sharing of sequence data, into a comprehensive consensus map.