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1.
A single specimen ofAlbula leptocephalus (55.7 mm SL) was collected from the southern coastal waters of Korea using an aquatic lamp. It is characterized by having a ribbonlike body with a small head and a well-forked caudal fin. Although the general appearance was similar to the leptocephalus ofA. vulpes including myomere counts and fin ray counts, the melanophore deposition was different from that ofA. vulpes. This leptocephalus specimen was confirmed withA. forsteri using the cytochrome b mtDNA (Cytb) analysis. The genetic distance ofCytb between the present leptocephalus andA. forsteri is 0.006-0.038, which falls into the cutoff point separatingAlbula species into eight deep lineages including the four valid species. Its genetic characteristic have more similarities to those of Fiji than those of Hawaii and the Northern territory of Australia.  相似文献   

2.
Marthasterias glacialis are found in the cool-temperate waters of the north-eastern Atlantic Ocean, in the subtropical waters of the Mediterranean Sea and along the south-western tip of Africa. The South African Marthasterias population includes two morphotypes, a smooth, spineless rarispina form and a spiny africana form, that have been described as separate species, subspecies, or forma by various authors over the past century. To test whether these two morphotypes represent separate species, and whether either, or both, are conspecific with the North-East Atlantic species, 78 Marthasterias were collected from the Cape Peninsula of South Africa. Morphological comparisons between individuals of the two forms showed no significant clustering of samples, indicating that there is no morphological separation of the two South African forms into distinct groupings. The africana and rarispina forms were also shown to be genetically indistinguishable, using a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene and the nuclear internal transcribed spacer 1 (ITS1). In addition, the COI sequences were also compared to those from European specimens, and phylogenetic reconstruction and intra- and interspecific levels of divergence suggested that the South African specimens form a single group that is genetically distinct from the European M. glacialis. Although the allopatric distribution, high genetic divergence (more than 3% for the COI fragment) and morphological differences suggest that the South African form should be raised to species status under the name Marthasterias africana, further work must assess an independent genetic marker (nuclear) to support raising the COI clade to species level. True M. glacialis have a spine-armament pattern of a series of three or more regular spine rows down the length of each arm, whereas M. africana are either covered in many irregularly spaced spines, or have an extraordinarily bare surface with only two spine rows per arm. Marthasterias africana may also have an actinal spine simulating the presence of a third inferomarginal spine. This work tentatively resolves the taxonomic dispute, elucidates the separation and amalgamation of the two African forms and suggests a single, uniquely South African Marthasterias species that might be distinct from the north Atlantic M. glacialis, although further analyses to test reproductive isolation between the North-East Atlantic and South African forms are required.  相似文献   

3.
通过传统形态学数据和框架结构数据相结合,应用方差、聚类、判别和主成分等4种多元分析方法,分析了太平洋双色鳗鲡与日本鳗鲡、美洲鳗鲡和花鳗鲡的形态差异。结果表明:(1)太平洋双色鳗鲡背鳍前端与臀鳍前端之间的垂线距离占全长的1.4%,属短鳍型鳗鲡。(2)太平洋双色鳗鲡与其它3种鳗鲡形态差异显著。在可数性状中,太平洋双色鳗鲡的总脊椎骨数显著小于日本鳗鲡,显著大于美洲鳗鲡和花鳗鲡,背鳍前脊椎骨数显著大于其它3种鳗鲡;在可量性状中,太平洋双色鳗鲡的吻长显著小于美洲鳗鲡和花鳗鲡,显著大于日本鳗鲡;在框架结构性状中,太平洋双色鳗鲡有6项性状与其它3种鳗鲡差异显著。(3)太平洋双色鳗鲡的背鳍起点与其它3种鳗鲡相比最靠后,背鳍起点在鳗鲡分类研究中可作为重要的框架结构定位点。本研究可为太平洋双色鳗鲡的合理引进和种质保护提供资料。  相似文献   

4.
2015年10月中旬,在浙江省舟山市近海的渔业资源调查中采集到天竺鲷标本,经鉴定发现其中黑边银口天竺鲷为浙江新纪录种。本文对采集的6尾黑边银口天竺鲷标本拍摄照片并开展形态特征和DNA条形码研究,对该种的拉丁学名进行校正。黑边银口天竺鲷的有效学名为Jaydia truncata(Bleeker,1854)。具有以下主要形态特征:背鳍鳍条数VII+I,9,胸鳍鳍条数16—17;背前鳞数4;第一鳃弓总鳃耙数3—4+11—13,发达鳃耙数1+9—10,角鳃弓上的鳃耙数9;前鳃盖骨边缘锯齿状;第一背鳍上端黑色,第二背鳍及尾鳍边缘黑色,第二背鳍与臀鳍中部各具一黑色纵纹。本研究分析了浙江海域5种天竺鲷科鱼类的形态差异,并编制了检索表。测定了6尾标本的DNA条形码,结合Gen Bank中所有学名为Jaydia truncata及其同种异名的同源序列分析,发现所有个体明显分为两个分支,且两者遗传距离达到0.149,表明两分支可能为不同的有效种,Gen Bank中只有AB890050和JQ681488与本研究序列结果相近。  相似文献   

5.
Larval specimens ofHalicampus punctatus were collected off Ulsan and Uljin in December 2002 (three specimens) and off Ulsan in December 2003 (one specimen). These specimens are characterized by the following morphological characteristics: rings, 14 + 35 = 49; subdorsal rings, 1 + 3 = 4; dorsal fin rays, 19 – 20; pectoral fin rays, 14 – 15; anal fin rays, 9; head length (HL), 5.8 – 6.7 in the standard length; snout length, 1.9 in HL; snout depth, 3.7 – 5.2 in snout length. The number of caudal fin rays 9 is less than those of the other species in the same genus 10. Wide stripe bands composed of small pigments are shown in the trunk and the tail. Melanophores are not found in the dorsal fin, the pectoral fin, and the anal fin except the caudal fin. The supraoccipital crest is on the head. The frontal ridge is on the dorsal side of front trunk. The blanched ridges on the opercular are fused with a main ridge like a tree branch. A few branched ridges that are small and narrow on the trunk and the tail are fused with the main ridges. We report these specimens as the first record in Korea and name them ‘Byeol-silgo-ki’ in Korean.  相似文献   

6.
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8.
石川粗鳍鱼由 D.S.Jordan和 J.O.Snyder(190 1)首次根据一尾采自东京湾口外的标本建立的 ,而本文的标本则采自中国黄海和东海等处。本种在体形、鳞片和身体结节等方面与皇带鱼(Regalecusglecus)相似 ,故常被混淆。经详细研究后 ,作者补充描述了本种的若干重要性状并同体形近似的皇带鱼对比 ,找出两种鱼在背鳍起点和肛门位置、腹鳍鳍条、头部骨片、口部结构、牙齿的有无及其分布、鳃耙数目、眼睛大小、侧线鳞及身体结节特点等方面的显著差别。  相似文献   

9.
Scorpaena onaria Jordan & Snyder (Scorpaeniformes: Scorpaenidae), previously known only from the northwestern Pacific Ocean, is reported from the southwestern Pacific Ocean for the first time on the basis of 19 specimens. The southwestern Pacific specimens are regarded as a southern population of S. onaria, characterised by a shorter supraocular tentacle and larger body size compared with the northwestern Pacific specimens. The southern population is described in detail including comparisons with all known Indo‐Pacific species of the genus Scorpaena. Analyses of 37 measurements of the southern population of S. onaria found that relative orbit diameter and second anal‐fin spine length became significantly smaller with growth. Initially cycloid, the scales enclosed by the posterior tips of the upper and lower opercular spines and opercular margin change to ctenoid with growth at c. 160–170 mm standard length. A mature female differed from an immature female and males in having a longer upper jaw, steeper dorsal profile of the snout, and shorter nasal spine. As a consequence, the species previously reported as S. neglecta from the Andaman Sea and northwestern Australia was re‐identified as S. onaria.  相似文献   

10.
Common carp (Cyprinus carpio L.) exhibits significant morphological variability in the shape and size of the caudal fin. In this study, we used 190 progeny from two F1 parents to identify and map quantitative trait loci (QTLs) that influence caudal fin length (CFL) and the ratio (RCS) between caudal fin length and standard length (SL) based on a microsatellite genetic map of common carp. A total of 15 QTLs were detected in seven different linkage groups. One significant and eight suggestive QTLs affecting CFL were identified on LG8, LG14, LG29, LG32 and LG44, which explained 8.0%–22.1% of the phenotypic variation; six suggestive QTLs affecting RCS were detected on LG8, LG32, LG46 and LG48, which explained 7.0%–15.4% of the phenotypic variation. The QTLs for caudal fin length detected in this study may serve as a starting point for identification of genes involved in caudal fin development in common carp.  相似文献   

11.
The intensity and effects of a flood in September–October 1975 on certain macrobenthic species of the soft substrata of the Swartkops Estuary were assessed. Significant decreases were recorded in populations of the bivalve Solen cylindraceus and the prawns Upogebia africana and Callianassa kraussi in the middle and upper reaches. The reductions were respectively some 93, 49 and 28 percent of the pre-flood values. No decrease was noted in populations of the bivalve Dosinia hepatica in the middle reaches or of U. africana in the lower reaches. Both large and small S. cylindraceus and C. kraussi were apparently affected by the flood, but in the case of U. africana it was primarily small individuals that suffered. Possible causes of these decreases are discussed.  相似文献   

12.
Two specimens of Valenciennea helsdingenii and one specimen of Chromis margaritifer were collected on scuba in October 2011 from Jeju Island, Korea. V. helsdingenii is characterized by a body with two dark stripes that connect the head and caudal fin, and a large dark spot between the third and sixth dorsal fin spines. C. margaritifer is characterized by a body that is dark brown anteriorly but white posteriorly at the boundary between the fifth dorsal fin soft ray and the ninth anal fin soft ray. The Korean name ‘Bok-gi-mang-duk-sok’ is proposed for the genus Valenciennea, the name ‘Du-jul-bok-gi-mang-duk’ is proposed for the species V. helsdingenii, and the name ‘Huinggo-ri-ja-ri-dom’ is proposed for C. margaritifer.  相似文献   

13.
Marine ecosystems provide a wide variety of diverse habitats that frequently promote migration and ecological adaptation. The extent to which the geographic distribution of marine organism has reshaped by human activities remains underappreciated. The limitations intrinsic to morphology-based identification systems have engendered an urgent need for reliable genetic methods that enable the unequivocal recognition of fish species,particularly those that are prone to overexploitation and/or market substitution. In the present study, however, an attempt has been taken to identify two locally adapted fish species, Siganus sutor(Valenciennes, 1835) and Seriolina nigrofasciata(Rüppell, 1829) of order Perciformes, which happens to be the first record in Odisha coast,Bay of Bengal. The diagnostic characteristics of Siganus sutor are: dorsal fin XIII-10, anal fin VII-9, pectoral fin 15,pelvic fin II-3, while that of Seriolina nigrofasciata dorsal fin VI-I-35, anal fin I-17, pectoral fin 16, pelvic fin 5. All COI barcodes generated in this study were matched with reference sequences of expected species, according to morphological identification. Bayesian and likelihood phylogenetic trees were drawn based on DNA barcodes and all the specimens clustered in agreement with their taxonomic classification at the species level. The phylogeographic studies based on haplotype network and migration rates suggest that both the species were not panmitic and the high-frequency population distribution indicates successful migration. The result of this study provides an important validation of the use of DNA barcode sequences for monitoring species diversity and changes within a complex marine ecosystem.  相似文献   

14.
A small goby, Trimma grammistes, was described in detail as the first reliable record from Korea based on 10 specimens (27.8~34.0 mm SL) collected from the coastal waters of Jeju Island. The species is easily differentiated from congeners by having no scales on the predorsal region, VI-I, 10 dorsal fin rays modally, I, 10 anal fin rays, 18 pectoral fin rays, 27~30 longitudinal scales as well as two dark longitudinal bands on the body.  相似文献   

15.
Between 1980 and 2001, a total of 661 African angel sharks Squatina africana was caught in the protective nets off KwaZulu-Natal, South Africa. The mean annual catch was 30 sharks (range = 11–69, SD = 12.4), with no trend in catch rate over the study period. Individuals were caught throughout the year and through much of the netted region, with a higher catch to the south. The sex ratio of the catch was 2.9 females:1 male. Males matured between 640mm and 700mm and females at about 700mm precaudal length (PCL). Mature males had clusters of thorn-shaped denticles, each about 2mm high, near the anterio-dorsal margins of both pectoral and pelvic fins. Of the mature females, 44% were pregnant, many of which contained only ova in utero. Embryos were present from April through to January. The average litter size was six, with length at parturition at least 240mm PCL. Most early-term pregnant females and all mature males were caught in the south. The reproductive cycle showed some seasonality and appeared to be biennial, with a gestation of about one year. Teleosts were the most common prey (76% of stomachs with food), followed by cephalopods (52%).  相似文献   

16.
Characteristic organisms are tabulated, and the substrate conditions briefly described for seven habitats in the Avon‐Heathcote Estuary, Christchurch, New Zealand. Temperatures and water movements within the estuary are outlined.

From April 1965 to April 1966, samples were collected by short otter‐trawl shots, gill netting, beach seine hauls, and dip netting; the limitations of the gear are noted. The distributions and movements are recorded for nine fish species : sand flounder, Rhombosolea plebeia (Richardson) ; yellow‐bellied flounder, Rhombosolea leporina (Hutton) ; common sole, Peltorhamphus novae‐zeelandiae (Gunther) ; ye'llow‐eyed mullet Aldrichetta forsteri (Cuvier and Valenciennes); kahawai, Arripis trutta (Bloch and Schneider); spotty, Pseudolabrus celidotus (Bloch and Schneider); cockabully, Tripterygion nigripenne (Cuvier and Valenciennes) ; common bully, Gobiomorphus basalis (Gray); and globe fish, Spheroides richei (Freminville).

Length‐frequency distributions showed that most of the nine species of fish used the estuary as a feeding area for adults and as a nursery area. Only two species did not migrate to and from the sea.

Length‐weight relationships for eight species showed that weight was a function of length approximately cubed, and that the exponential equation could be used to predict weight from length.

Regressions of caudal fin length on standard length for four species gave a positive correlation (r = +0.95). Relative proportions of body length to caudal fin length were related to habitat; fish of benthic habits had proportionally shorter caudal fins than pelagic fish.  相似文献   

17.
Knysna Estuary supports an estimated 30 full-time and 200 part-time subsistence fishers involved in bait collection, mud crab harvesting, and fishing. The mud prawn Upogebia africana dominates the bait-fishery, with estimated catches amounting to about 3% of the standing stock, suggesting sustainable use. Harvest of Marphysa spp. and Gorgonorhynchus dayi is conducted in a destructive manner. Most of the value of fishing lies in the setline catches of spotted grunter Pomadasys commersonnii and white steenbras Lithognathus lithognathus, whereas small species and individuals, particularly Cape stumpnose Rhabdosargus holubi, are also caught with handlines. Indications are that the linefishery is also sustainable at present. The subsistence fishery is worth an estimated R0.7-R1.1 million per annum, with full-time fishers earning at least R11 000-R17 000 per annum from the estuary. Currently operating under recreational regulations, the fishery is poorly controlled and fails to reach its full potential. The main threat to the estuary from damaging harvests of bait species, such as Marphysa spp. and G. dayi, should be discouraged through heavy penalisation of buyers and traders. Sales of mud prawn could probably be legalised. If off-take rates are found to be sustainable, sales of certain fish species could be legalised if access to the fishery could be effectively controlled under a co-management arrangement.  相似文献   

18.
The Indo-Pacific oyster Chama pacifica Broderip, 1835 (Mollusca, Bivalvia, Chamidae) is rarely found in the Northern Red Sea reefs of Eilat (Gulf of Aqaba), where it is outnumbered by its indigenous congener, Chama savignyi Lamy, 1921. The influx of Eritrean biota from the Red Sea into the Mediterranean Sea via the Suez Canal has led to the formation of massive Chama oyster beds along the Eastern Mediterranean shore. However, unlike the Northern Red Sea, the Eastern Mediterranean Chama beds are dominated by C. pacifica oysters, whereas C. savignyi is absent from this region. In an attempt to understand this difference in their respective distribution, the reproductive biology of both species was compared. Histological analysis of the male and female gonads, monitored monthly from March 2009 to August 2010 in both regions, revealed a similar reproductive cycle, comprising six stages: onset of gametogenesis, advanced gametogenesis, ripe, ready to spawn, spent and sexual rest. Female gonads demonstrated an additional, seventh stage – restoration, coinciding with inferred spawning of ripe gametes. Both species were found to be dioecious spawners, with a single, annual, temperature-dependent inferred spawning period. Chama pacifica was found to reproduce efficiently in maximal Mediterranean seawater temperatures not experienced by the Northern Red Sea Chama populations. This study demonstrates the high invasive potential of an oyster species despite its rarity in its source region.  相似文献   

19.
The larva of the primitive mayfly Oniscigaster wakefieldi, McLachlan 1873 (Ephemeroptera: Siphlonuridae) was studied in the Waitakere Stream, near Auckland, New Zealand, over a 17‐month period extending from July 1965— November 1966. A wide‐mouthed dragnet enabled monthly samples (average 46 specimens) to be collected for detailed studies of the larval growth pattern; this collecting method revealed that the species, previously thought to be rare, is numerous both in the study area and elsewhere in North Island, New Zealand.

O. wakefieldi has a univoltine life cycle with 20–25 larval instars. The larvae prefer different habitats according to their age and can be divided into three distinct groups: larvae 1–10 mm in length are found on finer sediments in quiet shallow water; 11–18 mm in length inhabit waters up to 50 cm deep where the substratum is mainly of pebbles (0.4–4.0 cm diameter) set in a silt matrix; and mature larvae 19–26 mm in length are found adjacent to dry emergent boulders, often at the base of riffles.

Three larval characters are described for the first time to separate the larvae of O. wakefieldi and O. distans. Sexual dimorphism is evident in O. wakefieldi populations by size difference; in the last larval instar, females average 4 mm longer than males. The known distribution of the species in North Island is illustrated.  相似文献   

20.
The study follows the embryogenesis of 16 species of viviparous clinid fishes (Clinidae, Teleostei), from the Cape south coast of South Africa and from Australia, with comparative remarks on the development of juveniles in oviparous species. The sperm intromitted into the female duct fertilise the eggs within the follicles. The embryos then develop in individual follicles, nourished by nutrients derived from the mother, until they are mature for release. During the reproductive season in the South African genera Clinus and Muraenoclinus, the female's ovaries harbour eggs and embryos at various stages of development, whereas in species of the Australian genera Heteroclinus and Cristiceps, most embryos in each ovary are at an approximately equal stage of development. The ovaries of the studied species fall into two groups: species of Heteroclinus and Cristiceps that produce numerous small eggs, and species of Clinus and Blennophis that produce fewer, larger eggs. As a consequence, Heteroclinus spp. and Cristiceps spp. bear and release high numbers of smaller embryos, of c. 10-13 mm long, whereas others (e.g. Clinus superciliosus, C. cottoides) bear fewer embryos, of up to 22 mm long. The organogenesis of various organs is described, with particular emphasis on chondrification and ossification. The onset of gut, sensory organ and skeletal development in Heteroclinus and related species occurs in embryos of 2.5-3.0 mm, whereas in Clinus spp. organ development starts in 5.0-6.0 mm embryos, and occurs in parallel both in the head capsule and at the caudal ends. Consequently, the pace of embryogenesis in the studied Australian small-egg species is faster in several aspects, and their embryos at the time of release are smaller than those of the large-egg species. The developmental sequences and related phenomena are discussed.  相似文献   

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