Early development of the Neotropical fish known as long sardine Triportheus auritus (Valenciennes 1850) (Characiformes,Triportheidae)

Larvae and juveniles of long sardine, Triportheus auritus, from the lower Amazon river was described, evaluating ontogenetic changes in their external mor­phology, pigmentation, fin development, morphometry, and meristics. A total of 93 individuals, 83 larvae and 10 juveniles were analyzed, they were captured monthly between 2014 and 2019 in the Amazon river channel and in macrophytes aquatic stands in the alluvial plains located in the lower Amazon River. From each specimen, morphometric and meristic data were measured and then the growth pattern between morphometric variables was analyzed. The larvae have an elongated body in a fusiform shape, superior mouth, simple nostril, pigmented spherical eyes and long intestine, surpassing the median region of the body. Initial pigmentation is scarce, but intensifies through development forming a pattern composed of three longitudinal bands concentrated in the ventral, cephalo-dorsal and lateral line regions. There are also pigments in the mandible, surrounding the mouth, under the swim bladder, intestine and fins. The sequence of complete fin formation is: caudal, anal, dorsal, pectoral and pelvic. The total number of myomeres ranged from 45 to 48 (25–29 preanal and 17–22 postanal). Morphometric relationships indicated differential growth for measurable morphometric parameters, with abrupt growth of snout length, head length and body height in the transition from flexion to postflexion stages. The pre-dorsal distance showed a decrease in the growth rate at the threshold from the larval to the juvenile period. The pre-pectoral and pre-anal distances showed negative allometric growth. In conclusion, the combination of body shape pigmentation pattern and, the formation sequence of fins allow the identification of the genus and coupled with the number of myomeres, morphometric relationships, and ray numbers of the anal fin ensure the differentiation of T. auritus from the other congeneric species. The metamorphosis occurred mainly at the end of the larval period and it is related to changes in the physiological and ecomorphological characteristics of the species.     

Gene banking of the neotropical fish Leporinus obtusidens (Valenciennes, 1836): a protocol to freeze its sperm in the field

A practical sperm cryopreservation protocol using a dry-shipper and a diluent of simple composition is described for the neotropical fish Leporinus obtusidens (Valenciennes, 1836). The cooling rate of the dry-shipper and its period of useful time, established under laboratory conditions, were respectively 25.7-30.8 degrees C/min (between 0 and -60 degrees C) and 9 days after charging. Sperm donors were selected on the basis of their hyperemic genital papilla and the ability to ooze milt under gentle manual pressure, during the reproductive months of November to January. Milt volume (1.3+/-0.3 mL; n=9 fish), fresh sperm motility rate (93.3+/-2.5%; n=6 fish), and sperm concentration (10.9+/-3.0 x 10(9)spermatozoa/mL of milt) were obtained. The sperm cryopreservation experiments were conducted with the following cryoprotectants (all at 10%, before mixing with milt): dimethyl sulphoxide (DMSO; n=10 fish), methanol (n=6 fish), propanediol (n=6 fish) and ethylene glycol (n=5 fish). Glucose (5%) and hen's egg yolk (10%) made up the diluents containing DMSO, ethylene glycol or propanediol. Milk powder (10%) replaced hen's egg yolk in the diluent containing methanol. Distilled water (up to 100%) completed the diluent solutions. Milt freezing (in 0.5-mL straws) was performed in the dry-shipper after 1:5 (milt:diluent) dilution. Thawed sperm cryopreserved in DMSO-containing diluent and activated by 119 mM NaHCO(3) gave the highest motility rate (62+/-14%). The fertilizing capacity of L. obtusidens sperm was tested using the combination of DMSO-containing diluent as the cryoprotectant and 119 mM NaHCO(3) as the activating solution. Oocytes were obtained from artificial spawning and fertilized with different proportions of spermatozoa. The greatest rate of fertilization (74%) occurred when the ratio of about 112,000 motile spermatozoa:oocyte was used. Thus, a protocol to freeze L. obtusidens sperm can be elaborated as follows. Milt (<1.5 mL fish(-1)) was readily available only in November to January; a simple solution, composed of 10% DMSO (concentration before adding milt), 5% glucose, and 10% hen yolk egg, in distilled water, was used as sperm diluent; cooling rate of 25-30 degrees C/min, yielded in a portable dry-shipper, was adequate to freeze diluted milt (1:5; milt:diluent), in 5-mL straws; about 112,000 thawed motile spermatozoa:oocyte activated by 119 mM NaHCO(3) assured a fertilization rate of 74%.     

Neocucullanus neocucullanus Travassos, Artigas et Pereira, 1928 (Nematoda: Cucullanidae) from the Characidae fish, Brycon hilarii Valenciennes, 1850, from Brazil

During investigation on the helminth parasites from Brycon hilarii Valenciennes, 1850 (Characiformes, Characidae), from River Juba, Tangará da Serra, state of Mato Grosso, Brazil, several specimens of the nematode Neocucullanus Travassos, Artigas et Pereira, 1928 were detected. A detailed study of this material, including scanning electron microscopy, allowed to identify these nematodes as N. neocucullanus Travassos, Artigas et Pereira, 1928 and to confirm N. multipapillatus Petter, 1989 as a junior synonym of N. neocucullanus.     

Myxosporean parasites of the catfish,Clarias lazera (Valenciennes)

Summary Five new species of myxosporean were found in the catfish Clarias lazera (Val.) in Israel. These species are described as: Henneguya laterocapsulata n. sp. (cyst-like trophozoites in the skin), H. suprabranchiae n. sp. (cyst-like trophozoites in the suprabranchial respiratory organs), Sphaerospora inaequalis n. sp. (spores in the lumen of the kidney tubules), Myxidium clariae n. sp. (spores in the gall bladder) and Myxobolus heterofilamentatus n. sp. (spores in the kidney, spleen, liver, suprabranchial respiratory organ, gills, heart and urinary bladder). Their taxonomic affinities to other species are discussed. ac]19860407     

Two new species of Leporinus (Characiformes: Anostomidae) from the Brazilian Amazon,and redescription of Leporinus striatus Kner 1858

Two new species of Leporinus are described from tributaries of the Rio Amazonas in Brazil. One species is known from the Jari and Tapajós River basins, and is identified on the basis of a gas bladder reduced in size, a dark midlateral stripe on the body, dark transverse bars on the dorsum, a subinferior mouth, three teeth on the premaxilla, four teeth on the dentary and 16 scale rows around the caudal peduncle. The second new species is known from the Tocantins, Xingu and Tapajós River basins, and is identified on the basis of three dark longitudinal stripes on the body, a subinferior mouth, three teeth on the premaxilla, four teeth on the dentary and 12 scale rows around the caudal peduncle. In addition, Leporinus striatus is redescribed based on type and additional specimens from the Río de La Plata, Amazonas, Orinoco, Atrato, Magdalena and Sinu River basins. Leporinus striatus is identified on the basis of four dark longitudinal stripes on the body, a subterminal mouth, three teeth on the premaxilla, four teeth on the dentary and 16 scale rows around the caudal peduncle.     

Phylogeography of the African catfish,Chrysichthys maurus (Valenciennes, 1839)

Polymorphism at 19 allozyme loci was studied in 227 individuals of the catfish, Chrysichthys maurus (Valenciennes, 1839), collected from ten populations representing nine different river basins in west Africa. Eleven of the loci studied were polymorphic. Analysis showed that populations clustered according to their geographical origin: eastern populations close to the root represented by a population of a closely related species (C. auratus); then populations from the centre of the species' range, followed by the more western populations. Networks observed, regression of genetic distances versus geographical distances, results of the Mantel test as well as the apomorphic status of two alleles suggested that the genetic differentiation corresponds to an isolation by distance model. These results strongly suggest that the populations initially occurred in the lagoons and rivers of Ivory Coast and from here spread to the western part of the species' range by progressively colonising basins from east to west.     

Length‐weight relationship of two mudskippers (Gobiidae: Oxudercinae) Oxuderces dentatus (Eydoux & Souleyet, 1850) and Scartelaos histophorus (Valenciennes, 1837) from Dhamara estuary,Odhisa, India

Oxuderces dentatus and Scartelaos histophorus species were collected seasonally from the Dhamara estuary (Odhisa, India) using scoop nets, cast nets as well as by hand for a period of 1 year (January 2015–December 2015). Length–weight relationships were estimated. Total lengths (TL) for O. dentatus ranged from 42 to 80 mm, and from 58 to 122 mm for S. histophorus. Similarly, total weights of O. dentatus and S. histophorus ranged from 2.5–10.7 g to 7.7–26.5 g, respectively. The ‘b’ values estimated for O. dentatus (2.718) and S. histophorus (2.689) were below 3. The condition factors of O. dentatus and S. histophorus were minimum in summer and maximum post‐monsoon.     

Testing monophyly of the freshwater fish Leporinus (Characiformes,Anostomidae) through molecular analysis

Monophyly of the genus Leporinus (Characiformes: Anostomidae) was tested by sequencing and analysing a total of 4732 bp, including two mitochondrial [cytochrome oxidase subunit 1 (CO1) and cytochrome b (Cytb)] and three nuclear [myosin heavy chain 6 cardiac muscle alpha (Myh6), recombination activating gene 1 (RAG1) and recombination activating gene 2 (RAG2)] loci for 22 species of Leporinus, or c. 25% of all described species in the genus. Phylogenetic tree analyses (maximum parsimony, maximum likelihood and Bayesian species tree) indicate Leporinus to be paraphyletic, with monophyly being rejected by both Kishino–Hasegawa and Shimodaira–Hasegawa tests. The sequenced species of Leporinus are distributed across five clades that are interleaved among other anostomid genera. Several taxonomic changes are suggested as being necessary to restore monophyly for the group. The clade containing the type species, Leporinus fasciatus, should be considered Leporinus sensu stricto and at least three new genera should be described for other species currently considered part of Leporinus.     

Morphological characteristics of the Pterodoras granulosus digestive tube (Valenciennes, 1821) (Osteichthyes,Doradidae)

Little is known about the digestive tube (DT) morphology of the fish Pterodoras granulosus. Therefore, macro‐, meso‐ and microscopic aspects of 15 P. granulosus DTs were analysed. The muscular layer was composed of striated skeletal muscle in the oesophagus and smooth muscle in the other segments. The epithelium progressed from a stratified pavement in the oesophagus to a simple column in the other segments, with a flat striated border in the intestine. A large number of mucus‐secreting periodic acid‐Schiff (PAS)‐positive cells were observed in the oesophagus. In the stomach, the number of glands in the region decreased towards the cardiac–fundic region, and none were found in the pylorus. The intestine showed an epithelium with absorption cells and an increasing number of PAS‐positive caliciform cells towards the distal region. Tests showed that the oesophagus is adapted for passing and preparing food for the chemical digestion that occurs in the stomach, which also has storage functions without grinding action. The proximal intestinal region was consistent with fat absorption, and the medium region, with the absorption of other nutrients. The distal region was short and consistent with a role in absorption for osmoregulation as well as in the formation, storage and disposal of faeces.     

Redescriptions of the Indo-West Pacific atherinid fishes, Atherinomorus endrachtensis (Quoy and Gaimard, 1825) and A. duodecimalis (Valenciennes in Cuvier and Valenciennes, 1835)

The Indo-Pacific marine atherinid fishes, Atherinomorus endrachtensis (Quoy and Gaimard, 1825) and Atherinomorus duodecimalis (Valenciennes in Cuvier and Valenciennes, 1835), having long been confused with each other, are redescribed as valid species based on the types and nontype specimens collected from the eastern Indian Ocean and West Pacific. Atherinomorus endrachtensis, known from the Philippines, Palau, North Sulawesi and Maluku Is. (Indonesia), and New Guinea, differs from other congeners in lacking a tubercle on the dentary and having the posterior tip of the upper jaw not extending beyond a vertical through the anterior margin of the pupil, usually 10–11 anal fin soft rays, 33–35 midlateral scales, a narrow midlateral band (ca. half midlateral scale width at anal fin origin), and 3 distinct longitudinal broken black lines laterally and ventrolaterally on the body. A lectotype is designated for Atherina lineata Günther, 1872, regarded as a junior synonym of Atherinomorus endrachtensis. Atherinomorus duodecimalis, known from Sri Lanka, Thailand, Yaeyama Is. (Japan), the Philippines, Indonesia, New Guinea, Queensland (Australia), and New Caledonia, differs from other congeners in having a tubercle on the posterior end of the dentary, the posterior tip of the upper jaw not extending beyond a vertical through the anterior margin of the pupil, usually 12–13 anal fin soft rays, 35–38 midlateral scales, and a narrow midlateral band (ca. 1/2 or 3/4 midlateral scale width at anal fin origin). Atherina balabacensis Seale, 1910 is regarded as a junior synonym of Atherinomorus duodecimalis. Received: June 29, 2000 / Revised: October 31, 2000 / Accepted: January 16, 2001     

Reproduction in the greenback grey mullet, Liza subviridis (Valenciennes, 1836)

This paper presents data on the reproductive biology of Liza subviridis , a little studied mullet species. The fish is heterosexual, exhibiting external fertilization. Six maturity stages can be macroscopically identified in the testes and seven in the ovaries. The macroscopic changes in the gonads are manifestations of histological changes occurring in the development of sperm cells and oocytes. First sexual maturity is attained in the length ranges of 9.5–11.5 cm and 10.5–11.5 cm in male and female fish respectively. The fecundity for fish measuring 10.3–13.9 cm in standard length ranged from 40 000–145 000 eggs. The relationship between fecundity ( F ) and length ( L ) can be represented as: F = 1.9044 L ^4.2998. The spawning duration in L. subviridis is restricted to a short and definite period, with all ripe ova being released within a single spawning act. A pronounced spawning season can be detected to extend from June to November. However, during off-seasons, some spawning also occurs. The correlations between spawning, rainfall and air temperature is discussed.     

Polydactylus konadaensis Mishra and Krishnan, 1993, a junior synonym of Filimanus xanthonema (Valenciennes in Cuvier and Valenciennes, 1831) (Perciformes: Polynemidae)

Polydactylus konadaensis Mishra and Krishnan, 1993 was described on the basis of two specimens from Konada, Andhra Pradesh, east coast of India. Although the new species was placed in the genus Polydactylus, our examination of the type specimens of the species showed them to represent a species of Filimanus. Furthermore, the characters of those specimens were consistent with those of the lectotype, paralectotype, and other specimens of F. xanthonema (Valenciennes in Cuvier and Valenciennes, 1831). Accordingly, Polydactylus konadaensis is herein regarded as a junior synonym of F. xanthonema. Received: July 2, 2000 / Revised: November 2, 2000 / Accepted: January 12, 2001     

The Genus Spiniferites Mantell, 1850 (Dinophyceae)

Following the recent official rejection of proposals for conservation of the generic name Hystrichosphaera, the diagnosis of its senior synonym Spiniferites is expanded in order to incorporate additional information gained since 1850 and all species according with the expanded diagnosis are listed (24 species are transferred to Spiniferites). The cyst-family name “Hystrichosphaeraceae” is replaced by the new name “Spiniferitaceae”.     

Sex chromosome polymorphism and heterogametic males revealed by two cloned DNA probes in the ZW/ZZ fish Leporinus elongatus

In order to study the divergence of teleost sex chromosomes, subtractive cloning was carried out between genomic DNA of males and females of the rainbow trout (XX/XY) and of Leporinus elongatus (ZW/ZZ). Inserts cloned in a plasmid vector were individually tested on Southern blots of DNA of males and females for sex specificity. No sex-specific insert was obtained from trout, but two out of ten inserts cloned from L. elongatus showed sex-specific patterns in this species: one corresponds to a sequence present on both Z and W chromosomes, while the other is W specific. Sequences of these two inserts show neither clear homology with other known sequences, nor an open reading frame. They cross-hybridize with the genomic DNA of Leporinus friderici, but without sex-specific patterns. Twenty-four L. elongatus adults were sexed by gonadal observation, chromosomed examination and Southern hybridization with one or the other insert. Ten males and 11 females had chromosomes and hybridization patterns typical of their sex. One ZW female was recognized as a male with the W-specific probe. This was also the case for two unusual ZW males, one having a male hybridization pattern with the other probe. These three atypical individuals may result from single genetic exchanges between four regions of the Z and the W, giving rise to three atypical W chromosomes. Finding males with such atypical heterochromosomes in a female heterogametic species may indicate that a gradual transition occurs between the heterogametic systems.     

Growth in four populations of Leporinus friderici (Bloch, 1794) (Anostomidae, Teleostei) in French Guiana

The growth rates of Leporinus friderici (Bloch, 1794) in four populations from four rivers of French Guiana are compared. According to a statistical analysis of growth curves using the method of maximum likelihood with the Gauss–Markardt algorithm, a marked difference is observed in the growth of the different samples which is attributed to the year of capture rather than to the geographical origin of fishes. It is demonstrated that the main factor affecting growth performances is the length of the rainy season, which corresponds for this species to the feeding period.     

Redescription of Diesingium lomentaceum (Diesing, 1850) (Cestoda: Trypanorhyncha)

Ardeirhynchus spiralis (Rudolphi, 1809) n. g., n. comb. (syns Echinorhynchus spiralis, Prosthorhynchus spiralis and Plagiorhynchus spiralis), a parasite of herons (Ciconiiformes: Ardeidae), is redescribed on the basis of the holotype from Ixobrychus minutus and specimens from Ardeola ralloides (new host record) in Bulgaria. A. spiralis is a member of the family Polymorphidae and not of the Plagiorhynchidae in which it was previously classified. Ardeirhynchus n. g. is distinguished from the most morphologically similar genus, Arhythmorhynchus Lühe, 1911, by the position of the male genital system, which occupies the posterior 1/8-1/6 part of the trunk, the distribution of hypodermal nuclei in groups in the anterior part and in lateral rows along the length of the posterior part of the trunk, a considerably shorter neck, minute trunk spines and a terminal genital pore.