We mapped the inferred long-distance migrations of four species of Amazonian goliath catfishes (Brachyplatystoma rousseauxii, B. platynemum, B. juruense and B. vaillantii) based on the presence of individuals with mature gonads and conducted statistical analysis of the expected long-distance downstream migrations of their larvae and juveniles. By linking the distribution of larval, juvenile and mature adult size classes across the Amazon, the results showed: (i) that the main spawning regions of these goliath catfish species are in the western Amazon; (ii) at least three species-B. rousseauxii, B. platynemum, and B. juruense-spawn partially or mainly as far upstream as the Andes; (iii) the main spawning area of B. rousseauxii is in or near the Andes; and (iv) the life history migration distances of B. rousseauxii are the longest strictly freshwater fish migrations in the world. These results provide an empirical baseline for tagging experiments, life histories extrapolated from otolith microchemistry interpretations and other methods to establish goliath catfish migratory routes, their seasonal timing and possible return (homing) to western headwater tributaries where they were born.
The pectoral spine of catfishes is an antipredator adaptation that can be bound, locked, and rubbed against the cleithrum to produce stridulation sounds. We describe muscle morphology of the pectoral spines and rays in six species in four genera of North American ictalurid catfishes. Since homologies of catfish pectoral muscles have not been universally accepted, we designate them functionally as the spine abductor and adductor and the arrector dorsalis and ventralis. The four muscles of the remaining pectoral rays are the superficial and deep (profundal) abductors and adductors. The large spine abductor and spine adductor are responsible for large amplitude movements, and the smaller arrector dorsalis and arrector ventralis have more specialized functions, that is, spine elevation and depression, respectively, although they also contribute to spine abduction. Three of the four spine muscles were pennate (the abductor and two arrectors), the spine adductor can be pennate or parallel, and ray muscles have parallel fibers. Insertions of pectoral muscles are similar across species, but there is a shift of origins in some muscles, particularly of the superficial abductor of the pectoral rays, which assumes a midline position in Ictalurus and increasingly more lateral placement in Ameiurus (one quarter way out from the midline), and Pylodictis and Noturus (half way out). Coincident with this lateral shift, the attachments of the hypaxial muscle to the ventral girdle become more robust. Comparison with its sister group supports the midline position as basal and lateral migration as derived. The muscles of the pectoral spine are heavier than muscles of the remaining rays in all species but the flathead, supporting the importance of specialized spine functions above typical movement. Further, spine muscles were larger than ray muscles in all species but the flathead catfish, which lives in water with the fastest currents. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.
Mapping differential elemental accumulation in fish tissues: assessment of metal and trace element concentrations in wels catfish (Silurus glanis) from the Danube River by ICP-MS
- Environmental science and pollution research international
- Published over 5 years ago
Studies of metal accumulation in fish are mainly focused on the muscle tissue, while the metal accumulation patterns in other tissues have been largely neglected. Muscle is not always a good indicator of the whole fish body contamination. Elemental accumulation in many fish tissues and organs and their potential use in monitoring programs have not received proper attention. In the present study, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn concentrations were assessed by inductively coupled plasma mass spectrometry (ICP-MS) in the following 14 tissues of the wels catfish (Silurus glanis) from the Danube River: muscle, gills, spleen, liver, kidneys, intestine, gizzard, heart, brain, gallbladder, swim bladder, vertebra, operculum, and gonads. A high level of differential elemental accumulation among the studied tissues was observed. The maximum overall metal accumulation was observed in the vertebra, followed by the kidneys and liver, with the metal pollution index (MPI) values of 0.26, 0.25, and 0.24, respectively. The minimum values were observed in the gallbladder, muscle, brain, and swim bladder, with MPI values of 0.03, 0.06, 0.07, and 0.09, respectively. Average metal concentrations in the fish muscle were below the maximum allowed concentrations for human consumption. The mean As, Cd, Pb, Cu, Fe, and Zn concentrations in the muscle were 0.028, 0.001, 0.001, 0.192, 3.966, and 3.969 μg/g wet weight, respectively. We believe that the presented findings could be of interest for the scientific community and freshwater ecosystem managers. There is a need for further research that would assess less studied tissues in different fish species.
An annotated list of tapeworms of the genus Gangesia Woodland, 1924 (Cestoda: Proteocephalidea), parasites of siluriform fishes in Asia, is provided. Based on the morphological examination of museum specimens and newly collected material from China, Japan and Russia, as well as the results of a previous revision of the Indomalayan species, only eight of more than 50 nominal taxa are considered to be valid. These are: from India and neighbouring countries, Gangesia bengalensis (Southwell, 1913) (type-species), G. agraensis Verma, 1928, both from Wallago attu (Bloch & Schneider) (Siluridae), G. macrones Woodland, 1924 from Sperata seenghala (Sykes) (Bagridae) and G. vachai (Gupta & Parmar, 1988) from different catfishes (type-host Eutropiichthys vacha (Hamilton); Schilbeidae), and, from the Palaearctic, G. margolisi Shimazu, 1994, a parasite of Silurus biwaensis (Tomoda) (Siluridae) in Japan, G. oligonchis Roitman & Freze, 1964 from Tachysurus fulvidraco (Richardson) (Bagridae) in Russia, and G. parasiluri Yamaguti, 1934 and G. polyonchis Roitman & Freze, 1964, both from Silurus asotus L. (Siluridae) in Japan and Russia, respectively. The poorly known G. oligonchis is redescribed. Seven new synonyms are proposed: G. chauhani Mathur & Srivastav, 2000, G. wallaguae Pradhan, Kulkarni, Kale & Wakle, 2010 and G. shivajiraoi Dhole, Waghmare & Chavan, 2012 are synonymised with G. agraensis; G. striatusii Bhure & Nanaware, 2012 and Silurotaenia govindii Sawarkar, 2013 with G. macrones; G. spasskajae Demshin, 1987 with G. polyonchis; and Silurotaenia spinula Chen, 1984 with Postgangesia orientalis Akhmerov, 1969. Gangesia pseudobagrae Chen, 1962 is considered to be a species inquirenda, whereas G. chauhani Mathur, 1992 and G. dineshei Jaysingpure, 2002 are recognised as unavailable names. An amended generic diagnosis of Gangesia and a key to the identification of its recognised species are also provided.
Testicular germ cells of channel catfish, Ictalurus punctatus, and blue catfish, I. furcatus were separated into four layers with Percoll density gradient centrifugation, containing different cell types (40 % in the first layer were spermatogonial stem cells, SSCs). Expression of seventeen genes was analyzed for cells from different layers by real-time quantitative PCR. Pfkfb4, Urod, Plzf, Integrin6, IntegrinV, Thy1 and Cdh1 genes showed the same expression change pattern in both channel and blue catfish as these genes were down-regulated in the spermatocytes and even more so in spermatids. Plzf and Integrin6 had especially high expression in SSCs and can be used as SSCs specific markers. Sox2 gene was up-regulated in spermatocytes and even more highly up-regulated in spermatids, which indicated it could be a spermatid marker. In contrast to channel catfish, Id4, Smad5 and Prdm14 gene expressions were strongly down-regulated in spermatocyte cells, but up-regulated in spermatid cells in blue catfish. Smad5 gene was down-regulated in spermatocytes, but up-regulated in both spermatogonia and spermatids, allowing identification as a marker for spermatocytes in blue catfish. Oct4, Id4, Gfrα2, Pum2 and Prdm14 genes showed different expression patterns in the testicular germ cells of channel and blue catfish. This may be a partial explanation to the differing responses of channel catfish and blue catfish to induced spawning technologies. The SSCs specific markers can be used for further SSCs labeling, which can increase the SSCs sorting efficiency and be applied in various studies involving SSCs and other germ cells.
The Loricariinae belong to the Neotropical mailed catfish family Loricariidae, the most species-rich catfish family. Among loricariids, members of the Loricariinae are united by a long and flattened caudal peduncle and the absence of an adipose fin. Despite numerous studies of the Loricariidae, there is no comprehensive phylogeny of this morphologically highly diversified subfamily. To fill this gap, we present a molecular phylogeny of this group, including 350 representatives, based on the analysis of mitochondrial and nuclear genes (8426 positions). The resulting phylogeny indicates that Loricariinae are distributed into two sister tribes: Harttiini and Loricariini. The Harttiini tribe, as classically defined, constitutes a paraphyletic assemblage and is here restricted to the three genera Harttia, Cteniloricaria, and Harttiella. Two subtribes are distinguished within Loricariini: Farlowellina and Loricariina. Within Farlowellina, the nominal genus formed a paraphyletic group, as did Sturisoma and Sturisomatichthys. Within Loricariina, Loricaria, Crossoloricaria, and Apistoloricaria are also paraphyletic. To solve these issues, and given the lack of clear morphological diagnostic features, we propose here to synonymize several genera (Quiritixys with Harttia; East Andean members of Crossoloricaria, and Apistoloricaria with Rhadinoloricaria; Ixinandria, Hemiloricaria, Fonchiiichthys, and Leliella with Rineloricaria), to restrict others (Crossoloricaria, and Sturisomatichthys to the West Andean members, and Sturisoma to the East Andean species), and to revalidate the genus Proloricaria.
Wadi El-Hitan, the UNESCO World Heritage Site, of the Fayum Depression in the northeast part of the Western Desert of Egypt, has produced a remarkable collection of Eocene vertebrates, in particular the fossil whales from which it derives its name. Here we describe a new genus and species of marine catfishes (Siluriformes; Ariidae), Qarmoutus hitanensis, from the base of the upper Eocene Birket Qarun Formation, based on a partial neurocranium including the complete left side, partial right dentary, left suspensorium, two opercles, left pectoral girdle and spine, nuchal plates, first and second dorsal spines, Weberian apparatus and a disassociated series of abdominal vertebrae. All of the elements belong to the same individual and some of them were found articulated. Qarmoutus gen. nov. is the oldest and the most complete of the Paleogene marine catfishes unearthed from the Birket Qarun Formation. The new genus exhibits distinctive features not seen in other African Paleogene taxa, such as different sculpturing on the opercle and pectoral girdle with respect to that on the neurocranium and nuchal plates, denticulate ornamentation on the skull bones arranged in longitudinal rows and forming a radiating pattern on the sphenotic, pterotic, extrascapular and the parieto-supraoccipital, indentations or pitted ornamentation on the nuchal plates as well as the parieto-supraoccipital process, strut-like radiating pattern of ornamentation on the opercle from the proximal articulation to margins, longitudinal, curved, reticulate ridges and tubercular ornamentations on the cleithrum, sinuous articulation between the parieto-supraoccipital process and the anterior nuchal plate, long, narrow, and arrowhead shaped nuchal shield, very small otic capsules restricted to the prootic. Multiple parsimony and Bayesian morphological phylogenetic analyses of Ariidae, run with and without “molecular scaffolds”, yield contradictory results for the placement of Qarmoutus; the genus is either a phylogenetically basal ariid, or it is deeply nested within the ariid clade containing New World species of Sciades.
Aspidoras mephisto n. sp. is described from the Anésio-Russão cave system, upper Tocantins River basin, Goiás, Brazil. The species can be readily distinguished from its congeners by troglomorphic features and also by presenting the following combination of features: infraorbital 1 generally with well-developed ventral laminar; or moderately developed; poorly-developed serrations on posterior margin of pectoral spine; nuchal plate not externally visible; dorsal fin, even in conspicuously colored specimens, with only dark brown or black chromatophores concentrated on rays, forming spots in some specimens; membranes hyaline; or sparse dark brown or black chromatophores on membranes, not forming any conspicuous pattern; and inner laminar expansion of infraorbital 1 moderately developed. Information about its habitat, ecology, behaviour and conservation status are provided and also a brief description of the juvenile stage.
An exceptionally preserved Late Devonian actinopterygian provides a new model for primitive cranial anatomy in ray-finned fishes
- Proceedings. Biological sciences / The Royal Society
- Published over 4 years ago
Actinopterygians (ray-finned fishes) are the most diverse living osteichthyan (bony vertebrate) group, with a rich fossil record. However, details of their earliest history during the middle Palaeozoic (Devonian) ‘Age of Fishes’ remains sketchy. This stems from an uneven understanding of anatomy in early actinopterygians, with a few well-known species dominating perceptions of primitive conditions. Here we present an exceptionally preserved ray-finned fish from the Late Devonian (Middle Frasnian, ca 373 Ma) of Pas-de-Calais, northern France. This new genus is represented by a single, three-dimensionally preserved skull. CT scanning reveals the presence of an almost complete braincase along with near-fully articulated mandibular, hyoid and gill arches. The neurocranium differs from the coeval Mimipiscis in displaying a short aortic canal with a distinct posterior notch, long grooves for the lateral dorsal aortae, large vestibular fontanelles and a broad postorbital process. Identification of similar but previously unrecognized features in other Devonian actinopterygians suggests that aspects of braincase anatomy in Mimipiscis are apomorphic, questioning its ubiquity as stand-in for generalized actinopterygian conditions. However, the gill skeleton of the new form broadly corresponds to that of Mimipiscis, and adds to an emerging picture of primitive branchial architecture in crown gnathostomes. The new genus is recovered in a polytomy with Mimiidae and a subset of Devonian and stratigraphically younger actinopterygians, with no support found for a monophyletic grouping of Moythomasia with Mimiidae.
The actinopterygian fish †Hemicalypterus weiri Schaeffer, 1967 is herein redescribed and rediagnosed based on new information collected from reexamination of museum specimens as well as examination of recently collected specimens from the Upper Triassic Chinle Formation of San Juan County, Utah, United States. †Hemicalypterus is distinguishable by its deep, disc-shaped compressed body; ganoid-scaled anterior half and scaleless posterior half; spinose, prominent dorsal and ventral ridge scales anterior to dorsal and anal fins; hem-like dorsal and anal fins with rounded distal margins; small mouth gape; and specialized, multicuspid dentition. This type of dentition, when observed in extant fishes, is often associated with herbivory, and †Hemicalypterus represents the oldest known ray-finned fish to have possibly exploited an herbivorous trophic feeding niche. A phylogenetic analysis infers a placement of †Hemicalypterus within †Dapediiformes, with †Dapediiformes being recovered as sister to Ginglymodi within holostean actinopterygians.