Mitochondrial DNA in Atherina (Teleostei,Atheriniformes): differential distribution of an intergenic spacer in lagoon and marine forms of Atherina boyeri

The big‐scale sand smelt Atherina boyeri lives in fresh water, brackish water and sea water of the western Atlantic Ocean and Mediterranean Sea. Previous studies concerning distribution, biometric characters and genetic molecular markers have suggested the possible existence of two or even three different groups or species of sand smelt, one ‘lagoon’ type and one (or two – punctuated and non‐punctuated on the flanks) ‘marine’ type. In this study, the presence and the localization of an insertion was described, c. 200 bp in length, in the mtDNA of the lagoon and marine punctuated specimens of A. boyeri and its absence in the marine non‐punctuated specimens, as well as in other two congeneric species, Atherina hepsetus and Atherina presbyter, and in the atheriniform Menidia menidia. The intergenic spacer is located between the tRNA^Glu and cytochrome b (cyt b) genes and shares a c. 50% sequence similarity with cyt b. The distribution and the features of the intergenic spacer suggest that it might have originated from an event of gene duplication, which involved the cyt b gene (or, more likely, a part of it) and which took place in the common ancestor of the lagoon and the marine punctuated specimens. The data obtained therefore support the hypothesis of the existence of three cryptic and, or sibling species within the A. boyeri taxon and provide a genetic molecular marker to distinguish them.     

Nuclear and mitochondrial phylogenetic analysis of big‐scale sand smelt Atherina boyeri complex in Greece

Genetic differentiation and phylogenetic relationships of big‐scale sand smelt Atherina boyeri specimens from 23 sampling sites in Greece and one from a lake in Turkey were investigated. A total of 2180 base pairs (bp) corresponding to the partial sequence of the mitochondrial gene cytochrome oxidase I (coI), cytochrome b (cytb) and control region, as well as of the nuclear protein‐coding gene rhodopsin (rh), were determined for the 143 specimens studied. Phylogenetic analysis of each gene segment separately and of the combined dataset revealed the existence of three different and well divergent lineages in Greece. The first corresponds to the lagoon form, in which a clear distinction between the Aegean and Ionian Sea was observed. The other two correspond to the punctuated and non‐punctuated marine forms that have been previously reported. The fact that in the present study a population without black spots on the flanks is clustered with the punctuated form and vice versa, however, suggests that differences in colour pattern do not seem to be a sufficient marker to discriminate the two marine forms. In contrast, the presence of a different length insertion between transfer RNA (tRNA) glutamic acid (tRNA^glu) and cytb genes in the lagoon and in one of the two forms of marine populations, and its absence from the rest marine‐form specimens confirms that this character is conserved and capable to be used for distinguishing the different forms. Even though the divergence values among the different forms were high, their phylogenetic relationships were not able to be resolved.     

Atherina punctata and Atherina lagunae (Pisces,Atherinidae), new species found in the Mediterranean sea. 2. Molecular investigations of three Atherinid species

On the basis of morphoanatomical parameters, the sand smelt species (Atherina boyeri Risso, 1810) is viewed as a highly polymorphic complex. In this study, intraspecific sequence variation in a portion of the cytochrome b gene was examined in 88 individuals from Tunisia and France. The correlation between the results of statistical analysis of the sequence data using a variety of tree-building algorithms and morphoanatomical analyses demonstrated the subdivision into three putative species: A. boyeri, which only includes non-punctuated fishes, A. punctata, which corresponds to punctuated fishes and A. lagunae, which corresponds to atherines living in lagoons.     

Genetic Divergence Among Marine and Lagoon Atherina boyeri Populations in Greece Using mtDNA Analysis

Genetic differentiation and phylogenetic relationships among 15 Atherina boyeri populations from several marine and lagoon or lake sites in Greece were investigated using mtDNA analysis. PCR-RFLP analysis of 12s, 16s rRNA genes and D-loop revealed 23 haplotypes. All the lake or lagoon populations, as well as the Kymi and Kalymnos populations that originated from sites with lagoonlike environmental conditions, showed haplotypes 1-6, clearly distinguishable from the marine populations, which exhibited types 7-23. The genetic divergence values estimated between the lagoon and the marine populations ranged from 5.55 to 10.45%. The high genetic differentiation observed between these two types of populations is also highlighted by the dendrograms obtained using UPGMA and maximum parsimony methods.     

Phylogenetic relationships of Atherina hepsetus and Atherina boyeri (Pisces: Atherinidae) populations from Greece, based on mtDNA sequences

The genetic divergence and the phylogenetic relationships of six Atherina boyeri (freshwater and marine origin) and five Atherina hepsetus populations from Greece were investigated using partial sequence analysis of 12s rRNA, 16s rRNA and control region mtDNA segments. Three different well divergent groups were revealed; the first one includes A. boyeri populations living in the sea, the second includes A. boyeri populations living in the lakes and lagoons whereas the third one includes all A. hepsetus populations. Fifty-seven different haplotypes were detected among the populations studied. In all three mtDNA segments examined, sequence analysis revealed the existence of fixed haplotypic differences discriminating A. boyeri populations inhabiting the lagoon and the lakes from both the coastal A. boyeri and the A. hepsetus populations. The genetic divergence values estimated between coastal (marine) A. boyeri populations and those living in the lagoon and the lakes are of the same order of magnitude as those observed among coastal A. boyeri and A. hepsetus populations. The results obtained by different phylogenetic methods were identical. The deep sequence divergence with the fixed different haplotypes observed suggests the occurrence of a cryptic or sibling species within A. boyeri complex.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 151–161.     

Multilocus phylogenetic analysis of the genus Atherina (Pisces: Atherinidae)

Sand-smelts are small fishes inhabiting inshore, brackish and freshwater environments and with a distribution in the eastern Atlantic and Mediterranean Sea, extending south into the Indian Ocean. Here, we present a broad phylogenetic analysis of the genus Atherina using three mitochondrial (control region, 12S and 16S) and two nuclear markers (rhodopsin and 2nd intron of S7). Phylogenetic analyses fully support the monophyly of the genus. Two anti-tropical clades were identified, separating the South African Atherina breviceps from the north-eastern Atlantic and Mediterranean Atherina' species. In European waters, two groups were found. The first clade formed by a well supported species-pair: Atherina presbyter (eastern Atlantic) and Atherina hepsetus (Mediterranean), both living in marine waters; a second clade included Atherina boyeri (brackish and freshwater environments) and two independent lineages of marine punctated and non-punctated fishes, recently proposed as separate species. Sequence divergence values strongly suggest multiple species within the A. boyeri complex.     

Mitochondrial DNA diversity in Atherina boyeri populations as determined by RFLP analysis of three mtDNA segments

The genetic differentiation and the phylogenetic relationships of eight Atherina boyeri Greek populations have been investigated at the mtDNA level. The populations studied are from two different lakes, a lagoon, the interface zone between the lagoon and the sea, and four marine sites. RFLP analysis of three mtDNA segments (12s rRNA, 16s rRNA and D-loop) amplified by PCR was used. Six, seven and eight restriction enzymes were found to have at least one recognition site at 12s rRNA, 16s rRNA and D-loop respectively. Twenty-one different haplotypes were detected among the populations studied. Several restriction patterns were revealed. These patterns can be used for the discrimination of the populations living in the sea ('marine' type populations) from the others inhabiting the lagoon and the lakes ('lagoon' type populations). The estimated net nucleotide sequence divergence between the populations examined ranged from 0 to 10.385%, while the Nst value of 0.92 indicates the existence of high interpopulation genetic differentiation. This high degree of differentiation detected between the 'lagoon' and 'marine' type populations makes the classification of these two types of populations as a single taxon questionable.     

Phylogenetic inference in Odontesthes and Atherina (Teleostei: Atheriniformes) with insights into ecological adaptation

This contribution provides an insight into Atheriniformes systematics based on four mitochondrial regions: 12S rRNA, cytb, COI and control region (2794bp in total). In the Atherinopsoidei (New World silversides), comparisons among five species of Odontesthes, O. argentinensis, O. bonariensis, O. smitti, O. hatcheri and O. incisa revealed a putative marine-freshwater pairing pattern of Odontesthes species, possibly driven by sea level fluctuations of South American waters. This study represents the first data on molecular phylogeny of Odontesthes species that can be of usefulness to biodiversity conservation policies. In the Atherinoidei (Old World silversides), Atherina boyeri was corroborated as a species complex constituted by a marine form, a marine with dark spots form and a brackish form. Concretely, Odontesthes and Atherina may represent geographically replicated models to study genetic adaptation and speciation of marine species to brackish and freshwater habitats. In addition, phylogenetic analyses supported Odontesthes and Atherina as monophyletic taxa and their separation into two differentiated suborders Atherinopsoidei and Atherinoidei, respectively.     

Environmental factors controlling the spring immigration of two estuarine fishes Atherina boyeri and Pomatoschistus spp. into a Mediterranean lagoon

Atherina boyeri , a pelagic species, mainly entered a Mediterranean lagoon in the Rhone River Delta, during the day, whatever the flow direction. Flow velocity did not appear to be a significant factor and its swimming abilities seemed to be sufficient to cope with the observed velocity. The combined responses of Pomatoschistus spp., benthic species, to the different environmental factors clearly demonstrated a change in behavioural response during their ontogenic development, i.e. a shift from passive to active or active-passive migration. Young Pomatoschistus spp. (<20 mm L _T) exhibited a behaviour that correspond to the classical selective tidal stream transport of young fishes towards estuarine areas (passive drifting). Large Pomatoschistus spp. were also able to enter the lagoon with the flow, but they remained negatively affected by the flow velocity. The diel cycle appeared to be the main factor controlling the immigration of A. boyeri into the lagoon whereas Pomatoschistus spp. seemed more sensitive to hydrographic conditions prevailing at the connection.     

Age and Growth of Atherina Atherina boyeri (Atherinidae) from Southwestern Crimea (Black Sea)

Journal of Ichthyology - The size and age structure and growth of Atherina boyeri from southwestern Crimea were studied. The ratio of males and females was 1.00 : 1.38, the proportion of males...     

The biology of Boyer's sand smelt, Atherina boyeri Risso in the Bardawil Lagoon on the Mediterranean coast of Sinai

The present study describes some aspects of the life history of Boyer's sand smelt Atherina boyeri in the hypersaline Bardawil Lagoon on the Mediterranean coast of the Sinai peninsula, Egypt. Monthly samples were collected with a small-mesh experimental beach-seine during the years 1973–1974. Age determinations were based on otoliths readings and length frequency distributions which indicate that the Bardawil Lagoon population consists mostly of 0-age group. The largest recorded fish was 63 mm in standard length (S.L.). Length-weight relationship has been calculated as: W = 13.7 × 10⁻⁶× L ^2.93 where W = weight (g) and L =S.L. (mm). Atherina boyeri mature at the length of 34 mm. Spawning takes place from March to September. The average number of eggs in the ovary of a ripe female at the beginning of the spawning season was found to be 522. Females of all sizes were more numerous than males. In immature fish, less than 34 mm long, females constituted 53% of the population. In larger fish the number of females was higher; in fish over 34 mm long females constituted 64% and in fish over 51 mm—96%. Atherina boyeri in the Bardawil Lagoon feeds on both zoobenthos and zooplankton, mainly amphipods and copepods. Polychaetes, mysidaceans, insects and fish were also represented. Atherina boyeri is the host of endoparasitic Trematoda, Acanthocephala and Nematoda. The examined fish were found to have metacercaria in their mesenteries and liver.     

Spinitectus osorioi n. sp. (Nematoda: Cystidicolidae) from Chirostoma spp. (Osteichthyes: Atherinidae) in Lake Pátzcuaro, Michoacán, México.

Spinitectus osorioi (Nematoda: Cystidicolidae) is described from the freshwater atherinids Chirostoma estor and Chirostoma attenuatum from Lake Pátzcuaro in the Mesa Central, Michoacán State, México. This nematode is characterized by a conspicuous protuberance on the ventral surface of the distal end of the long spicule that distinguishes it from its congeners in North America and in the neotropics. In addition, the species can be readily distinguished from 4 of the 5 nominal species of North American freshwater Spinitectus by the absence of either a terminal barb or heel on the short spicule and from Spinitectus mexicanus by the spination. Previous records of Spinitectus carolini from Chirostoma spp. in México (Lakes Pátzcuaro and Zirahuén) refer to S. osorioi, and the species appears to be specific to Chirostoma spp. The geological history of the Mesa Central drainages and the historical biogeography of freshwater atherinids in this region suggest that the origin of S. osorioi may be associated with either the marine history of their hosts or with host-switching from more distantly related freshwater hosts after colonization of freshwater environments by atherinids.     

Functional groups of lagoon fish species in Languedoc Roussillon, southern France

Ten functional traits of fish species were related to habitat, diet or food acquisition, to propose a classification of 21 lagoon fishes into 10 functional groups. The selection of traits was based on their functional interest and the ease of measurement. Some groups were taxonomically related containing species belonging to the same genus, e.g . Syngnathus , Atherina or Pomatochistus . Species with a flat body shape constituted another group and three species ( Anguilla anguilla , Gambusia affinis and Callionymus pusillus ) formed individual groups. These results could be used to constitute functional units and to simplify such complex ecosystems and their interactions.     

A new atherinomorine genus Doboatherina (Atheriniformes: Atherinidae) with a review of included species

Ichthyological Research - The new Indo-Pacific marine atherinid genus Doboatherina is established based on both morphological analysis and molecular-phylogenetic results. Furthermore, four species...     

Acanthocephalan infections in Atherina boyeri (Pisces: Atherinidae) from Tirso.

Infections by the acanthocephalan Telosentis exiguus (Von Linstow, 1901) and another unknown acanthocephalan were studied in the sand smelt Atherina boyeri (Risso, 1810) from the Tirso River mouth in Sardinia. Only a few specimens of T. exiguus (1 male and 2 cystacanths) were found in the host digestive tract; some larvae of an unidentified acanthocephalan encysted in the liver of A. boyeri were also found and are described.     

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     

Age, growth and mortality of a semi-isolated lagoon population of sand smelt, Atherina boyeri (Risso, 1810) (Pisces: Atherinidae) in an estuarine system of northern Greece

Age, growth and mortality of the sand smelt, Atherina boyeri (Risso, 1810), were studied in the Vistonis estuarine system in northern Greece from February 1989 to August 1990. Overall male : female sex ratio was 1 : 2.5, statistically different from unity. Total lengths ranged between 13 and 105 mm. Age determination based on scale readings showed that the population comprised five age‐groups. Sand smelt grew allometrically (b = 3.22) and rapidly during the first year, achieving 60% of their growth. Growth parameters of the population were: L_∞ = 116.97 mm, K = 0.35 year⁻¹ and t_o = −0.99 years. Growth index ϕ′ was 3.69 of all individuals studied. The mean growth index was significantly lower for the Mediterranean lagoon (ϕ′ = 3.73, SD = 0.1) than for Atlantic populations (ϕ′ = 3.92, SD = 0.06). Total mortality rate was Z = 1.29 year⁻¹ and natural mortality M = 0.95 year⁻¹. Males had a lower life span than females, the latter dominating length classes >60 mm. Exploitation rate of the studied population was E = 0.26, suggesting that stock size might increase and generate improved possibilities for exploitation.     

A further occurrence of Atherina boyeri Risso 1810 in North-Eastern Atlantic waters

Synopsis A further occurrence of Atherina boyeri in British waters is recorded. This species has a distribution which can be broadly defined as Mediterranean but has been occasionally recorded in waters which are beyond the northerly limits of its normal range. These records have usually been associated with localised thermal pollution but, at Oldbury-upon-Severn, England, this is probably not so. Morphometric and meristic data are presented which show clearly that this is a genuine record of A. boyeri. The existence of this species in waters with minimal, if any, thermal enrichment raises interesting questions regarding its distribution.This example and the other abnormal records of A. boyeri are, therefore, considered in relation to a number of environmental parameters. The parameters discussed, namely increased water temperature, decreased salinity and lagoon conditions have all been implicated in previous records.The conclusion tentatively reached is that A. boyeri is capable of surviving under a cooler temperature régime than that with which it is normally associated. Normally its range is restricted by inter-specific competition. In conditions of calmer water, however, in which there is also reduced salinity it is able to compete and maintain itself successfully.     

Macrozoobenthic community structure in a poikilohaline Mediterranean lagoon (Laki Lagoon, northern Aegean)

The community structure of the macrobenthic fauna was studied in the overall area of Laki Lagoon in September 1997 (salinity 32–35 psu) and monthly from February 1998 to February 1999 in the innermost part of the lagoon (salinity 0.1–6.8 psu). Community structure was analyzed by means of uni- and multivariate methods. In September 1997, the macrofauna in the outer part of the lagoon was characterized by a higher diversity and the occurrence of both lagoonal and marine species, and in the innermost part by a higher total abundance and the occurrence of a few lagoonal species. The combination of distance from the sea, depth, salinity and sediment organic matter correlated best with the spatial distribution pattern of the macrobenthic fauna. Community structure in the innermost part of the lagoon showed a seasonal periodicity. Species composition during spring 1998, at 0.1–2.0 psu, was similar to that in September 1997. During summer the macrobenthic fauna became impoverished, but recovered from late summer onwards. The salinity increase during summer (up to 5–7 psu) was followed by the appearance of marine species in the innermost part of the lagoon. Total abundance displayed a peak in late spring and a lower one in mid-autumn. The seasonal dynamics of the faunal assemblage was mainly governed by water temperature. Predation pressure by Atherina boyeri may have contributed to quantitative community changes during autumn.     

Validity of the atherinid fish, Atherinomorus vaigiensis (Quoy and Gaimard, 1825), with comments on its synonymy

The Australian marine atherinid fish, Atherinomorus vaigiensis (Quoy and Gaimard, 1825), having long been synonymized under A. lacunosus (Forster in Bloch and Schneider, 1801), is redescribed as a valid species based on the holotype and non-type specimens. Atherinomorus vaigiensis, known only from eastern and western Australia, differs from other congeners in lacking a distinct tubercle on the posterior end of the dentary and having the posterior tip of the upper jaw not extending beyond a vertical through the anterior margin of the pupil, 12–15 anal fin soft rays, 24–28 lower gill rakers, 39–42 midlateral scales, and a narrow midlateral band (width about 2/3 to 5/6 that of midlateral scale at level of anal fin origin). Atherina cylindrica Valenciennes in Cuvier and Valenciennes, 1835 and Pranesus ogilbyi Whitely, 1930 are regarded as junior synonyms of Atherinomorus vaigiensis. Received: April 26, 2001 / Revised: July 11, 2001 / Accepted: July 16, 2001