Number Of Gill Rakers Research Articles

Genetic and morphological differences between yellowtail kingfish (Seriola lalandi) from the Bohai Sea, China and the Southern Ocean, Australia

The aquaculture of yellowtail kingfish (Seriola lalandi) has expanded around the globe, including China. Genetic resource of Chinese S. lalandi urgently needs to be assessed for improving production. Here, we collected wild S. lalandi samples from the Bohai Sea, China and evaluated its genetic diversity based on 17,690 nuclear loci. A population from the Southern Ocean, Australia was used for comparison. The analyses showed that the Chinese and Australian S. lalandi formed two completely distinct clusters and there was no genetic introgression from the Australian S. lalandi into the Chinese S. lalandi population. The genetic diversity is slightly lower, but comparable in Chinese versus Australian yellowtail kingfish (Chinese population, expected heterozygosity: 0.19, observed heterozygosity: 0.19, nucleotide diversity: 0.19 ± 0.09; Australian population, expected heterozygosity: 0.23, observed heterozygosity: 0.22, nucleotide diversity: 0.22 ± 0.11). Overall, our results indicated that Chinese S. lalandi could be a potential subject for genetic breeding programs. We also investigated morphological characters and developed molecular markers for population identification. Comparison of meristic characters between the Chinese population and the Australian population revealed that main shape difference were in the number of dorsal spines, dorsal fin rays and the number of upper gill rakers. Geometric morphology based on eight landmarks also revealed significant difference between the two populations including the distance between the tip of snout to origin of pelvic fin and the distance between the tip of snout to origin of pectoral fin. These morphological characters can be used for easy identification of the Chinese S. lalandi.

Identification of Black Bullhead (Ameiurus melas) and Brown Bullhead (A. nebulosus) from the Western Great Lakes: Recommendations for Small Individuals

Distinguishing Black Bullhead (Ameiurus melas) from Brown Bullhead (A. nebulosus) can be difficult, in part, due to conflicting evidence regarding reliable meristic and morphological characters with which to base identifications. The possibility of hybrids with intermediate traits further complicates diagnosis. Identification guides have typically focused on adults, leaving guidance for juveniles largely undescribed. We compared morphological identifications of Black Bullhead and Brown Bullhead with a cytochrome c oxidase I (COI) barcode and microsatellite assignments. Specifically, we examined: (1) gill-raker count, (2) anal-fin ray count, (3) prominence of pectoral-spine serrae, (4) DNA barcoding using the COI gene, and (5) cluster analysis of nine microsatellite loci. With the exception of anal-fin ray counts, we found a high degree of agreement among all methods. Microsatellite analysis identified two clearly distinct genetic groups, and these groups corresponded to individuals identified as Black Bullhead and Brown Bullhead based on morphology. Although Black Bullhead and Brown Bullhead did not share COI haplotypes (except for one individual), we found greater intraspecific genetic distances among individuals identified as Brown Bullhead than between Brown Bullhead and Black Bullhead, demonstrating that caution is warranted against using COI haplotypes as a barcode to solely distinguish the two species. Pectoral-spine serrae prominence was a useful character to distinguish the two species and worked especially well on individuals <125 mm total length. Gill-raker counts of euthanized fish in the laboratory were appropriate for the identification of all sizes of Black Bullhead and Brown Bullhead (using the lowest number of gill rakers on the first gill arch if asymmetry was observed). Finally, microsatellites did not show evidence of recent hybridization at our sampling sites. We recommend using pectoral-spine serrae prominence to distinguish between Black Bullhead and Brown Bullhead in the field and using gill-raker counts for laboratory based identification.

A new species of the genus Verilus (Teleostei, Percomorpha, Acropomatidae) from Brazil.

A new species of Acropomatid fish, Verilus costai sp. nov., is described from a single locality off Belmonte, State of Bahia, Brazil. It resembles Verilus pseudomicrolepis (Schultz, 1940) from the Caribbean Sea. The two are considered vicariant and they are interpreted to be separated from other species of the genus Verilus by (amongst other characters) the presence of fangs on the dentary (vs. only villiform teeth), the anal fin formula (II+9 vs. III+7) and the naked occiput (vs. scaled). However, formal establishment of a separate genus is postponed until a complete phylogenetic review of the family has been performed. Verilus costai can be distinguished from V. pseudomicrolepis by its higher number of gill rakers (27-31 vs. 21-25), lower number of pseudobranchial filaments (15-23 vs. 21-28), shorter snout length (8.2-11.3 vs. 11.3-13.4 % of SL), and more compressed otoliths (OL:OH = 1.3-1.35 vs. 1.35-1.5). In addition, the fossil otolith-based species Verilus mutinensis (Bassoli, 1906) from the late Miocene to middle Pleistocene of the Mediterranean is thought to be related and indicates that in the past this group was more widely distributed than nowadays and comprised more vicariant species.

Influence of feeding structures and early development on foraging guild assignment in four co-occurring fishes (Family Sciaenidae)

The use of a functional guild, which distills organisms into groups based on a shared role within an ecosystem, is a beneficial tool for fisheries management because it reduces data complexity, streamlines statistical analyses, and places species in an ecosystem context by defining their functional role within a community. However, few studies consider the ramification of ontogeny on guild assignments and assume species occupy a static foraging guild throughout their lives. The aim for this study was to examine the development of feeding structures and diet in four, closely related species of sciaenids (Family Sciaenidae) that forage in the water column throughout their life history (1) to determine if the structures needed to exploit microhabitat use of the water column are present at early ontogenetic stages and (2) to assess guild transitions using a hierarchical clustering approach. Significant differences were only detected in ascending process length and cb1 gill raker count among the examined sciaenids. Larimus fasciatus consumed zooplankton throughout ontogeny and possessed a shorter ascending process and a greater number of cb1 gill rakers. Cynoscion nebulosus transitioned from zooplanktivory in the larval period to piscivory as an early juvenile and possessed a longer ascending process and fewer cb1 gill rakers. Bairdiella chrysoura and C. regalis were both zooplanktivorous as early juveniles and consumed more epibenthic (benthic crustaceans and worms) prey and possessed more elongate gill rakers compared to C. nebulosus. Foraging studies that combine diet and morphological analyses are needed to place individuals into foraging guilds while capturing key life history transitions that influence foraging habits and guild assignment.

Morphological Variation of the Sea Silverside Odontesthes regia in Regions with Dissimilar Upwelling Intensity along the Humboldt Current System

We evaluated the influence of areas with dissimilar upwelling intensity along the Humboldt Current System on the morphological variation of the economically important sea silverside Odontesthes regia by using geometric morphometric (GM) and meristic data of populations sampled off Northern Peru, Central Peru, Southern Peru-Northern Chile, and Central-Southern Chile (CSCH). Multivariate analyses of variance, a UPGMA tree, and discriminant analyses of meristic counts separated CSCH individuals, which had slightly higher numbers of gill rakers and radius of the anal fin. Permutation tests and canonical variate analyses of GM data distinguished all populations and highlighted deformations in the head and fins. Variations in GM and meristic analyses were significantly correlated with values of the sea surface temperature and surface chlorophyll-a concentrations. Morphological differences among populations might be associated with the spatial coastal upwelling dynamic of the Humboldt Current System, which highlights the role that this system plays in relation to the phenotypic variation of fish.

A New Species of Fairy Wrasse (Teleostei: Labridae: Cirrhilabrus) from Mesophotic Coral Ecosystems of the Verde Island Passage, Philippines

The new species, Cirrhilabrus briangreenei, is described on the basis of the holotype and six paratypes collected from mesophotic coral ecosystems of the Verde Island Passage, Philippines, between depths of 82 and 110 m. The new species is most closely related to Cirrhilabrus pylei, but it differs primarily in the presence of: more pored scales on the posterior lateral line (7–9 vs. 5–6); a lower number of circumpeduncular scales (14 vs. 16); a lower number of gill rakers (16–17 vs. 18–20); and differences in coloration details of the dorsal and caudal fins. Both species differ from all other congeners in sharing the following combination of characters: pelvic fins very long (56.5–70.0% SL), often extending past anal-fin terminus in males; caudal fin scintillating and iridescent in males; dorsal fin with sinuous scribbling in both sexes; anterior dorsal fin with a metallic blue spot on first one to two interspinous membrane spaces; snout with three parallel stripes from maxilla to anterior edge of orbit; and rest of head with a network of short broken pinstripes in both sexes. These characters are also distributed in part amongst other species of Cirrhilabrus, in particular, C. katoi, C. lineatus, C. rhomboidalis, and C. rubrimarginatus, and their putative relationships are discussed on the basis of meristic, morphometric, and molecular sequence data. We briefly comment on the variability of morphological characters within Cirrhilabrus and their implications towards phylogenetic classification, with remarks on methods for data collection for species of Cirrhilabrus.

Phenotypic diversity in an endangered freshwater fish Squalius microlepis (Actinopterygii, Leuciscidae).

Squalius microlepis was examined from recent and historical collections within the known range of the species with special emphasis on intraspecific variability and variations, and compared to its closest relative species S. tenellus (in total, 193 specimens; 33 absolute and 52 proportional measurements and ratios, and 12 counts including vertebrae). Squalius tenellus was perfectly differentiated in all statistical analyses and can be diagnosed by 76–95 (vs. 64–80) scales in lateral series, 68–83 (vs. 58–77) lateral-line scales, (17)18–20 (vs. 13–16(17)) scales above lateral line, and (7)8–10 (vs. 4–7) scales below lateral line. Squalius microlepis was morphologically heterogeneous, with two phenotypes readily distinguishable (phenotype 1 corresponding to S. microlepis s. str. as defined by its lectotype) by a combination of many characters; those contributing most to the discrimination were number of gill rakers, length of lower jaw (% interorbital width), and head length (% SL). Only phenotype 1 was found in the Ričina-Prološko Blato-Vrljika karst system; most of the specimens from the lower Matica and the Tihaljina-Trebižat karst system were identified as phenotype 2; the sample from karstic poljes near Vrgorac contained both phenotype 1 and 2, and individuals of intermediate morphology. As very limited molecular data exist on the two phenotypes of S. microlepis, we refrain from any taxonomic conclusions until new molecular approaches (and new markers) are used. We also report on a dramatic reduction of the area of distribution and abundance of S. microlepis in recent years.

Two new species of Thrissina (Clupeiformes: Engraulidae) from the northern Indian Ocean and redescription of Thrissina vitrirostris (Gilchrist and Thompson 1908)

Thrissina cultella sp. nov., and Thrissina serena sp. nov., are described from the Bay of Bengal and northwestern Indian Ocean, respectively. Although both species resemble T. vitrirostris (Gilchrist and Thompson 1908), which is redescribed from both type and non-type specimens, in having a long upper jaw (posterior tip reaching to pectoral-fin insertion) and similar numbers of gill rakers and ventral scutes, the two new species differ in having fewer transverse scales (9–10 in both vs. 11–12 in T. vitrirostris). Thrissina cultella differs from T. serena in having a slender body [24.4–26.9% of standard length (SL) vs. 26.6–29.4% SL in T. serena], shorter head (25.2–27.1% SL vs. 26.2–27.3%) and pectoral fin (17.5–19.1% SL vs. 19.5–21.3%), and longer pelvic fin (9.3–10.5% SL vs. 7.8–8.7%).

Cisco diversity in a historical drainage of glacial Lake Algonquin

Cisco (Coregonus artedi (sensu lato) Lesueur, 1818) forms matching in appearance to Blackfin Cisco from the Laurentian Great Lakes occur in four lakes in Algonquin Park, Ontario, Canada, a historical drainage of glacial Lake Algonquin (precursor of lakes Michigan and Huron). Their occurrence may represent colonization from glacial Lake Algonquin drainage patterns 13 000 calibrated years BP or independent evolution within each lake. Gill-raker numbers, temperature at capture depth during lake stratification, and hurdle models of habitat distribution are summarized. Blackfin (nigripinnis-like) in the four lakes had higher gill-raker numbers than artedi-like cisco captured in nearby lakes or within the same lake. Two lakes have a bimodal gill-raker distribution that indicate co-occurrence of two forms. Blackfin occupied the hypolimnion with a peak depth distribution at 20–25 m. Maximum depth for blackfin was 35–40 m. The presence of the opossum shrimp (Mysis diluviana Audzijonyte and Väinölä, 2005) appears necessary for the occurrence of cisco diversity in lakes but not sufficient in all cases. The presence of two forms of cisco in at least two lakes points to the possibility of the colonization hypothesis or the ecological speciation hypothesis as accounting for this phenomenon. Genetic analysis is needed to determine which of these hypotheses best accounts for the occurrence of blackfin in Algonquin Park.

Morphological differences between species of the sea bass genus Lateolabrax (Teleostei, Perciformes), with particular emphasis on growth-related changes.

Morphological differences, including growth-related changes, were examined in three morphologically similar East Asian sea bass species, Lateolabraxjaponicus, L.maculatus and L.latus. In many cases, body measurements indicated specific patterns of growth-related proportional changes. Lateolabraxlatus differed from the other two species in having greater body depth, caudal peduncle depth, caudal peduncle anterior depth, snout length, and upper and lower jaw length proportions. In particular, scatter plots for caudal peduncle anterior depth relative to standard length (SL) in that species indicated complete separation from those of the other two species, being a new key character for identification. Comparisons of L.japonicus and L.maculatus revealed considerable proportional differences in many length-measured characters, including fin lengths (first and second dorsal, caudal and pelvic), snout length, post-orbital preopercular width (POPW) and post-orbital length. In particular, snout length (SNL) and POPW proportions of the former were greater and smaller for specimens >200 and ≤ 200 mm SL, respectively. Because the scatter plots of these proportions for the two species did not overlap each other in either size range, identification of the species was possible using a combination of the two characters. In addition, scatter plots of the POPW / SNL proportion (%) of L.japonicus and L.maculatus were almost completely separated throughout the entire size range examined (border level 90%), a further aid to identification. The numbers of pored lateral line scales and scales above the lateral line tended to increase and decrease with growth, respectively, in L.japonicus, whereas scales below the lateral line and gill raker numbers tended to increase with growth in L.maculatus. Because the ranges of these meristic characters may therefore vary with specimen size, they are unsuitable for use as key characters. Accordingly, a new key is proposed for the genus Lateolabrax.

Short Communication: Species confirmation of juvenile cloudy grouper, Epinephelus erythrurus (Valenciennes, 1828), based on a morphologic analysis and partial CO1 gene sequencing

Abstract. Ariyanti Y, Farajallah A. 2019. Species confirmation of juvenile cloudy grouper, Epinephelus erythrurus (Valenciennes, 1828), based on a morphologic analysis and partial CO1 gene sequencing. Biodiversitas 20: 914-921. The genus Epinephelus is the most species among the genera within the subfamily Epinephelinae. Species identification techniques for groupers, especially in the Epinephelus, are commonly based on color patterns and a suite of morphological characters, including body shape and the size and number of fins, scales and gill rakers. In some species, juveniles are morphologically distinct from adults of the same species, making morphological identification highly problematic. This present work will provide some morphological description or variations of juveniles that have been identified as Epinephelus erythrurus based on CO1 sequences. Further, the present study demonstrates that a molecular genetic technique, based on partial sequencing of the mitochondrial CO1 gene, may be used for the rapid species confirmation of every developmental stage and phase of an organism (juvenile E. erythrurus). Two DNA sequences of E. erythrurus from the Pangandaran District (7o43’8.31”S 108o30’11.59”E) have been submitted to GenBank under accession numbers KP998441 and KP998442.

Austrolebias ephemerus (Cyprinodontiformes: Rivulidae), a new annual fish from the upper Rio Paraguai basin, Brazilian Chaco.

A new species of Austrolebias belonging to the A. bellottii species group is herein described from the Brazilian Chaco, Mato Grosso do Sul state, constituting the northernmost record of the genus in Brazil, as well as the first record of this genus on the left bank of the Rio Paraguai. The new species is distinguished from all other species of the A. bellottii group by the following combination of characters: pectoral fin posterior margin reaching vertical between base of 4th and 7th anal fin rays in females, a high number of gill rakers in the first branchial arch, a lower head width in both sexes, and a small number of neuromasts in the preopercular series. Additionally, we provide information on ecology and the conservation status of the new species.

Morphometric and Meristic traits of four flatheads (family: Platycephalidae) occurring along the East coast of India

Study on a meristic traits of Kumococius rodericensis Sorsogona tuberculata Platycephalus indicus and Rogadius serratus (family Platycephalidae), occurring along the East coast of India, was conducted to find easily differentiating traits. The study was based on the samples collected from landing centers situated along the East coast of India, during February 2015 to March 2016. A total of thirty-one morphometric and meristic characters were measured, counted and subjected to statistical analysis using software Statistica. Among eighteen morphometric measurements, five measurement (distance between upper and lower jaw, length of upper preopercular spine, snout length, maximum length of first dorsal spine, maximum length of second dorsal spine) did not show difference when subjected to factor analysis. Varimax raw factor rotation on factor loading 0.7 were selected for scatterplot of canonical score among root 1 and root 2, which revealed existence of distinct group of species. Number of gillrakers, spot on caudal fin, number of pored scale on lateral line and preopercular spine revealed significant variations among the species. The proportional measurements with their head length (HL) viz. Preorbital length: head length (POL:HL), Inter orbital width: head length (IOW:HL), and maximum eye diameter: head length (MED:HL) also revealed significant difference among the species. The study revealed certain morphological characters those can easily identify the flathead species.

Changes in diatom and chironomid assemblages of boreal taiga in East Siberia (58N, Lake Aunakit, Russia) during the last 4.2 ka

The author has studied phenetic and taxonomic relationships of the Baikal endemic sculpins of the genus Cottocomephorus Pellegrin 1900. For this purpose, the author has performed a morphometric investigation by five meristic and 29 plastic characters, as well as analysed the characteristics of colouring and the number of preopercular spines. The author has confirmed the validity of three species: C. grewingkii (Dybowski, 1874), C. inermis (Yakowlev, 1890) and C. comephoroides (Berg, 1901). The differentiation of the studied species is based on the number of gill rakers and preopercular spines, the width of the interorbital distance, height and width of the head, the length of the pectoral fins and the characteristics of the in-life colouration. Based on the revision of the diagnostic features, the author has suggested a new key to identify species.

A new species of Lipogramma from deep reefs of Roatan, Honduras (Teleostei, Grammatidae).

A new species of Lipogramma is described from submersible collections at 122–165 m depth off the coast of Roatan, Honduras, in the western Caribbean. The new species is distinguished from all other species in the genus by its bright blue coloration on the head, nape, and dorsal portion of the trunk beneath the spinous dorsal fin, a prominent round black blotch below the origin of the spinous dorsal fin, and a high number of gill rakers. A molecular phylogeny based on mitochondrial and nuclear genes shows that the new species belongs to a clade containing L.levinsoni, L.regia, and L.anabantoides. At Roatan, submersible observations of this and other Lipogramma species indicate clear, interspecific habitat partitioning by depth and substrate.

Rapid niche expansion by selection on functional genomic variation after ecosystem recovery.

It is well recognized that environmental degradation caused by human activities can result in dramatic losses of species and diversity. However, comparatively little is known about the ability of biodiversity to re-emerge following ecosystem recovery. Here, we show that a European whitefish subspecies, the gangfisch Coregonus lavaretus macrophthalmus, rapidly increased its ecologically functional diversity following the restoration of Lake Constance after anthropogenic eutrophication. In fewer than ten generations, gangfisch evolved a greater range of gill raker numbers (GRNs) to utilize a broader ecological niche. A sparse genetic architecture underlies this variation in GRN. Several co-expressed gene modules and genes showing signals of positive selection were associated with GRN and body shape. These were enriched for biological pathways related to trophic niche expansion in fishes. Our findings demonstrate the potential of functional diversity to expand following habitat restoration, given a fortuitous combination of genetic architecture, genetic diversity and selection.

Delimitation of Alosa species (Teleostei: Clupeiformes) from the Sea of Azov: integrating morphological and molecular approaches.

Shads of the genus Alosa are essential to commercial fisheries across North America and Europe, but in some areas their species boundaries remain controversial. Traditional morphology-based taxonomy of Alosa spp. has relied heavily on the number of gill rakers and body proportions, but these can be highly variable. We use mitochondrial (mt)DNA (coI and cytb) and genome-wide single nucleotide polymorphisms (SNP) along with morphological characters to assess differentiation among endemic Ponto-Caspian shads in the Sea of Azov. Morphological species assignments based on gill-raker number were not congruent with genetic lineages shown by mtDNA and SNPs. Iterative analysis revealed that genetic lineages were associated with sampling location and several other morphometric traits (caudal peduncle depth, pre-anal length and head length). Phylogenetic analysis of the genus placed Ponto-Caspian Alosa spp. in the same evolutionary lineage as endangered Alosa spp. endemic to Greece, highlighting the importance of these findings to conservation management. We conclude that gill-raker number is not reliable for delimiting species of Alosa. This taxonomic uncertainty should be addressed by examining type material to provide a robust integrative classification for these commercially important fishes.

A New Species of Luminous Percoids of the Acropoma Genus (Acropomatidae)

A new species, Acropoma leobergi sp. n. from the Arafura Sea, belonging to a group of species with a short U-shaped luminous organ slightly receding behind the anus, is described. From other species of this group, the described species is well distinguished by a combination of such features as a small number of gill rakers in the outer row on the first arc (18–20), the presence of the chin boss, the presence of cycloid scales on the sides of the body, four longitudinal rows of scales between the beginning of the first dorsal fin and lateral line, and dense melanophore pigmentation on the dorsal surface of the luminous organ. Earlier representatives of this species, apparently, were mistakenly identified with the northwestern Pacific species A. japonicum (from Japan to Vietnam and the Philippines). A new synonymy was established: Acropoma lacrima Okamoto et Golani, 2017 = A. splendens (Lloyd, 1909).

New Subspecies of Twaite Shad Alosa fallax balticus (Clupeidae)

We have carried out a comparative analysis of the morphological features of Twaite shad Alosa fallax based on our own data (Curonian Lagoon, Baltic Sea (2008 and 2009)) and comparative materials (collections of Russian and foreign natural history museums, including published data). The results of this study allow us to assign the Baltic Sea population of Twaite shad to the taxonomic status of subspecies Alosa fallax balticus subsp. nov. The Baltic Sea subspecies differs from other subspecies of Atlantic Twaite shad A. fallax by a lower number of gill rakers (mean 36.7) and vertebrae (53.6) and larger pre dorsal distance (46.2% SL or 41.6–42.7% TL). A. fallax balticus is one of the subspecies that have the lowest number of gill rakers on the first gill arch among subspecies of the species Alosa fallax in the northeastern Atlantic and seas of its basins.

New Data on Morphological Features of the Branchial Apparatus of Sparsely Rakered and Medium Rakered Morphs of Whitefish Сoregonus lavaretus (L.) from the Largest Subarctic Lake

The distribution and feeding of the ecological morphs of whitefish is studied in Lake Imandra, the largest subarctic water body. Data on the hydrochemical and hydrobiological characteristics of the reaches of the lake, as well as on the morphological features of the whitefish branchial apparatus with low and medium gill raker number, are obtained. A relationship between feeding preferences of whitefishes and size characteristics and trophic levels of the habitats is revealed.