陕北横山晚三叠世造迹鱼类恢复

运用遗迹化石恢复造迹动物的形态结构是古遗迹学研究的难点.近年来在陕北横山晚三叠世地层中发现大量完好的鱼类游泳遗迹, 能较好地恢复造迹鱼类鳍的着生位置及相关形态结构, 确定造迹鱼的类型.通过游泳遗迹的形态结构与鱼类形态结构相互关系的分析, 建立了游泳遗迹形态结构参数与造迹鱼类形态结构参数之间的数学关系式.通过计算显示同一遗迹种的鱼鳍间距与鱼体长度比值一定, 这与现代鱼类形体特征一致.应用该方法恢复了研究区两遗迹种的造迹鱼类, 其中Undichna britannica造迹鱼类的尾鳍和臀鳍间距与体长之比为0.3, 臀鳍和胸鳍间距与体长之比为0.45~0.5, 尾鳍和腹鳍间距与体长之比为0.49~0.5, 与邻区相同层位发现的鱼类实体化石Wayaobulepis zichangensis相关特征一致.另一遗迹种Undichna tricosta恢复的尾鳍和臀鳍间距与体长之比约为0.35, 可能与本区相同层位发现的Saurichthys huanshenensis特征相似.      

黄河下游边滩表面的鱼类遗迹

黄河下游边滩泥质沉积物表面常遗留有鱼类的各种痕迹,有(1)游泳迹:包括由鲻鱼尾鳍刻划形成的各种线状延伸和非线状延伸的单一波线;臀鳍形成的线状延伸的单一波线;腹鳍紧贴泥质沉积物表面形成的平行成对波线;胸鳍扇动时形成的不平行断续成对波线;以及上述各种波线所形成的组合.(2)鲻鱼进食遗留下来的圆环状或圆坑状牧食迹,可组合成葡萄状、弧形、星点状、线状、"之"字形、带状等各种形态.(3)鱼粪.本文对上述各种鱼类痕迹的特征、成因、形成环境进行了详细阐述,并认为缓慢沉积的泥质沉积物表面是鱼迹形成并保存的前提.     

The first record of redfieldiiform fish (Actinopterygii) from the Upper Triassic of Korea: Implications for paleobiology and paleobiogeography of Redfieldiiformes

A new genus and species of redfieldiiform fish, Hiascoactinus boryeongensis gen. et sp. nov., is described based on a nearly complete specimen from the Upper Triassic Amisan Formation of South Korea. Hiascoactinus is distinguished from other redfieldiiforms by having a barely ornamented dermal skull surface except for the snout region, two heteromorphic suborbitals arranged vertically behind the postorbital, a pistol-shaped suprascapular, and dorsal and anal fins with divided fin membranes between rays. The morphological features of the snout region and dorsal and anal fins of Hiascoactinus provide important clues to understand its feeding and swimming behavior. All previously proposed Asian redfieldiiform fossils are inaccurately classified, and consequently, Hiascoactinus is regarded as the only valid redfieldiiform taxon in Asia. Hiascoactinus is assigned to the basal group of redfieldiiforms primarily based on the presence of an antopercle. The basal phylogenetic position of Hiascoactinus indicates that basal redfieldiiforms dispersed from the southern Gondwanaland to the easternmost Laurasia through the terrestrial water system, and these two landmasses were connected during the Late Triassic.     

Food habits and feeding behavior of the cownose ray,Rhinoptera bonasus,in lower Chesapeake Bay

The most important food item of the cownose ray,Rhinoptera bonasus, in the Virginian tributaries of lower Chesapeake Bay is the soft shell clam,Mya arenaria. The Baltic macoma,Macoma balthica, ranks a distant second. Adult rays feed on deep burrowing mollusks, juveniles on shallow- or non-burrowing bivalves. Foraging schools of rays invade tidal flats during the flood tide. Stirring motions of the pectoral fins combined with suction from the expansive orobranchial chamber are probably used to excavate deep burrowing bivalves.     

Respiratory response of striped bass (Morone saxatilis) to suspended solids

Oxygen consumption rates were measured individually for mixed groups of male, female, and immature striped bass,Morone saxatilis, in filtered Patuxent River, Maryland, water and in filtered water containing suspensions of either fuller’s earth or Patuxent River sediment. Oxygen consumption was determined at fixed swimming speeds at two temperatures, 15 and 22.5°C. Oxygen consumption of striped bass in filtered 15°C water increased as swimming speed increased. At 22.5°C, the same range of swimming speeds had no effect on rates of oxygen consumption. Similar data were obtained with fish swimming at the same speeds in water containing 0.79 g per liter fuller’s earth particles (15°C), and among those swimming at 31.7 and 49.0 cm per s in water containing 1.32 g per 1 Patuxent River sediment (22.5°C). Male and female striped bass respiration rates were similar under all test conditions. At 15°C, striped bass oxygen consumption rates during exposure to fuller’s earth while swimming at 8.6 and 31.7 cm per s did not differ from rates of fish swimming at the same speeds in filtered water. At 49.0 cm per s, rates were significantly depressed. Respiration rates of fish exposed to Patuxent River sediment at 22.5°C while swimming at 31.7 and 49.0 cm per s were significantly lower than those of fish in filtered water. Respiratory response of striped bass to suspended particle stress was manifested by depressed oxygen consumption. This is considered a short-term response to an acute stress. This response and the potential for hematological response to chronic suspended particle stress are discussed.     

Recent trends in estuarine fisheries: Predictions of fish production and yield

Trends in global and United States fish catches were examined to determine the status of estuarine fisheries yields relative to those from other ecosystems. Potential marine fish production, based upon primary production relationships, was estimated globally and for specific marine ecosystems, including estuaries. While global fish catches increased substantially during the past two decades and continued to increase through 1989, catches of estuarine-dependent species have peaked or stabilized. In the United States, total catches have increased but many estuarine-dependent fisheries have declined, although the declines in catches are no more dramatic than those of heavily-fished continental shelf species. Overfishing probably is the primary cause of declines in estuarine and shelf fisheries. A few estuarine-dependent species of the United States have experienced substantial increases in harvests since 1970, for example, Pacific salmons, menhaden, and penaeid shrimps. The percentage contribution of major estuarine fisheries to the United States commercial catch declined between 1970 and 1990, although the yield of these species increased substantially. Global marine fisheries production at trophic level 2.5 was estimated to be 1,359 million tons. Potential yield was estimated to be 307 million tons, but the 1989 world marine catch was only 86.5 million tons. The major fraction, 196 million tons, of the estimated potential yeild was for the open ocean where technological constraints may prevent its full realization. Of the remaining 111 million tons of the potential, 18.0 million tons (16.2%) may come from estuaries and probably already is fully exploited. The potential catches from shelves, 68.5 million tons (61.6%), and upwelling areas, 24.8 million tons (22.2%), while considerably larger than those from estuaries, are lower in a relative sense (per unit area) than fisheries production and potential catch in estuarine zones. Relationships between fish production, fish harvest, and primary production were examined in specific estuaries. The developing role of aquaculture and its effect on estuarine fisheries are discussed.     

New species of Saurichthys (Actinopterygii: Saurichthyidae) from Middle Triassic (Anisian) of Yunnan Province, China

Abstract: Saurichthys dawaziensis sp. nov., from the third member of the Gejiu Formation (Anisian of Middle Triassic) in the vicinity of Luoping, Yunnan Province, is a small to medium- sized saurichthyid fish. It is characterized by the efferent pseudobranchial arteries penetrating on the parasphenoid and the mandible sensory canal with a branch in the angular. The new species is more derived than the Lower Triassic species in having a relatively narrow postorbital region, short preopercular, single ossification of the sclerotic ring, small haemal arches between the pelvic fins and the anal fin without ossified spines, and in the absence of quadratojugal. It is more primitive than the Middle and Upper Triassic Saurichthys in having fringing fulcra and numerous segments in the unpaired fins, and the presence of both prae- and post-zygapophyses in the neural arches. Some anatomic changes related to the vertebral column and unpaired fins of the genus are also discussed.     

Exploratory and Instantaneous Swimming Speeds of Amphidromous Fish School in Shallow-Water Coastal Lagoon Channels

Fish school swimming speeds is essential for ecological and management studies. The multibeam sonar in horizontal beaming provided dynamic echo traces of mobile fish schools. We used two school swimming speed indicators: the average of a series of instantaneous speed values, and the exploratory speed. These swimming speeds were estimated for each fish school observed on the basis of their Euclidian position within the sonar beams. The average ISS values per school ranged from 0.15 m s⁻¹ to 4.46 m s⁻¹, while the ESS values per school were lower, ranging from 0.04 m s⁻¹ to 3.77 m s⁻¹. Multibeam sonar technology makes it possible to measure fish school swimming speeds in their natural habitat at small spatio-temporal scales. This methodology can therefore be used to analyse in situ their movements, and has a wide range of applications in behavioural studies and management purposes.     

A new species of Gladiopycnodus (Coccodontoidea,Pycnodontomorpha) from the Cretaceous of Lebanon provides new insights about the morphological diversification of pycnodont fishes through time

The Coccondontoidea is a distinctive superfamily of pycnodont fishes characterized by a series of derived characters, including thick and well-ossified cranial bones supporting horns and spines and a hypertrophied pectoral girdle sutured to the skull forming a sort of cephalo-torax. A new distinctive coccodontoid species, Gladiopycnodus byrnei n. sp., is described from the Cenomanian locality of Hjoûla, Lebanon. This new species exhibits a unique combination of features that clearly support its inclusion within the coccodontoid family Gladiopycnodontidae, including an extremely elongate snout forming a sword-shaped rostrum, thick dermal bones ornamented with rounded tubercles, large supracleithrum and cleithrum extensively sutured to the skull, and irregularly imbricated scales covering the entire body. The new taxon differs from type species G. karami by having different meristic counts and body proportions, dermal bones strongly ornamentated, skull roof with partially fused bones, scales ornamented with small tubercles, and rounded scales covering the caudal peduncle absent. The presence of pectoral fins in our exquisitely well-preserved specimen allowed us to redefine the morphology of the genus Gladiopycnodus, also modifying the diagnosis of the family. In order to interpret the patterns of morphospace occupation and quantify the morphological diversification of pycnodonts through time, the geometric morphometric approach was used. The morphospace analysis revealed that a significant increase in morphological disparity of pycnodonts during the Late Cretaceous was related, at least in part, to the appearance of the representatives of the superfamily Coccodontoidea. The rapid evolutionary radiation of these well-armored pycnodonts was interpreted as an adaptive solution in response to the large predatory-prey escalation in the context of the Mesozoic Marine Revolution.     

A new basal actinopterygian fish from the Late Ladinian of Monte San Giorgio (Canton Ticino, Switzerland)

A new taxon of Late Ladinian basal actinopterygian is described on the basis of a single specimen from the Meride Limestone (Kalkschieferzone) of Meride (Canton Ticino, Switzerland). The species is characterized by a single plate-like branchiostegal, a suboperculum larger than the operculum, a maxillary fixed and posteriorly expanded, a large and rectangular dermopterotic and a large triangular dermosphenotic; the scales are rectangular to rhomboidal, the lepidotrichia of median fins are segmented from their base and the caudal fin shows epaxial rays. These features resemble the condition of the Redfieldiiformes, a freshwater fish group, whose presence in Europe is still controversial, owing to poor preservation of specimens found so far.     

A new percoid fish from the Eocene of Monte Bolca, Italy: Hendrixella grandei gen. & sp. nov.

A new genus and species of percoid fish, Hendrixella grandei gen. & sp. nov. is described from the upper Ypresian limestone of Monte Bolca, Italy. It is based on four well-preserved specimens that show an elongate and slender body and a unique combination of features, including possession of 11 + 13 vertebrae, two series of intermuscular bones, fused haemal spine of third preural centrum, caudal fin with 17 principal rays and 11 upper and eight lower procurrent rays, predorsal formula 0/0/1 + 1/1/, two separated dorsal fins with rayless pterygiophore in-between, and a single supernumerary spine in both dorsal and anal fins. Due to this unique combination of features, Hendrixella cannot be placed within any existing fossil or extant percoid families and it is placed incertae sedis in the Percoidei. The possession of two series of intermuscular bones represents an unambiguous autapomorphy of Hendrixella. A comparative analysis of the distribution of intermusculars among percomorph fishes indicates that the intermuscular bones of the upper series can be homologized with the epineurals and those of the lower series are the homologs of the epicentrals of non-acanthomorphs.     

最早期脊椎动物的镶嵌演化

采自云南昆明市海口地区下寒武统筇竹寺组的昆明鱼为活埋标本 ,其软躯体构造保存极为精美 ;来自同一层位的海口鱼为正常死亡后埋藏 ,除身体最后部略有腐烂外 ,整体特征保存良好。这两种鱼皆呈鱼形 ,不仅具带鳃软骨的原始头颅和比无头类简单“人”字形肌节更为复杂的双“人”字形肌节 ,而且还发育了原始偶鳍和围心腔构造 ,表明它们已演化成高等脊索动物有头类 ( Craniata)或称脊椎动物 ( Vertebrata)。另一方面 ,它们的低骨化性 (如尚未发育出真正的脊椎骨 )和生殖系统演化的滞后性 (仍具多对生殖腺 )等原始特征 ,使它们呈现典型的镶嵌演化性。     

Pteraspidomorphs (Vertebrata), the Old Red Sandstone,and the special case of the Brecon Beacons National Park,Wales, U.K.

Pteraspidomorphi are Ordovician to Devonian, jawless vertebrates devoid of paired fins that have developed a variety of phenotypes of mostly demersal aquatic animals of the neritic province. Some, however, were active swimmers in the water column or near to the surface. They show many convergences in adaptive variations with the other ossified agnathan vertebrates or ostracoderms, that is the osteostracans, galeaspids and pituriaspids. They are traditionally known as Old Red Sandstone (ORS) fish, and have been interpreted as fresh-water inhabitants. However, recent palaeoecological and sedimentological analyses have shown that they were near-shore, shallow-marine fishes in the Ordovician, that they occupied marine environments on the Silurian Baltic platform and a wide variety of environments in the Devonian, including those of the ORS (lagoonal, estuarine, deltaic, and open platform). Their peak of diversity was reached in the Early Devonian, and they all disappeared before the Frasnian-Famennian boundary biotic crisis. Within Earth sciences, they are used in biostratigraphy, palaeoecology, and palaeobiogeography. They are good tools for dating siliciclastic sedimentary series of the Silurian and Devonian, including the ORS, and they are good markers of the margins of Ordovician to Devonian palaeocontinents (Laurentia, Baltica, Siberia, Gondwana).     

Fifty-Five Years of Fish Kills in Coastal Texas

The designation of Texas as a “hotspot” for fish mortalities relative to the other 22 coastal US states is of serious concern for scientists, resource managers, and the public alike. We investigated the major sources and causes of fish kills in coastal Texas from 1951 to 2006. During this 55-year period, more than 383 million fish were killed, 72% of which were Gulf menhaden (Brevoortia spp.). We examined the relationships between climate and the physical features of Texas bays and estuaries as well as the consequences of high-density industrialization and urbanization along several coastal centers on fish kills, including the impact of eutrophication, algal blooms (toxic and nontoxic), and hypoxia. Galveston and Matagorda Bays had the highest number of fish kill events and total number of fish killed. The largest number of fish kill events and the highest number of fish killed occurred during the warmest months, particularly in August. The leading cause of fish kills was found to be low dissolved oxygen concentrations caused by both physical and biological factors. From 1958 to 1997, about two thirds of the mortalities from low oxygen concentrations were caused by human activities. With the population predicted to double in Texas by 2050, mostly along the coastal areas, natural resources will require additional protection. Further increases in nutrient loading are expected in areas unable to keep up with construction of sewage treatment facilities. Defining the sources and causes of fish kill events in Texas will allow better management and conservation efforts.     

Effects of hypoxic disturbances on an estuarine nekton assemblage across multiple scales

Disturbances influence ecological communities over a wide range of scales. We investigated the effects of localized hypoxic disturbances on an estuarine fish assemblage at several spatial (m² and 10s km²) and temporal (days, seasons, years) scales in a multivariate framework (temperature, salinity, depth, dissolved oxygen). We examined whether seasons, years) scales in a multivariate framework (temperature, salinity, depth, dissolved oxygen). We examined whether there were consistent changes in fish and crustacean estuarine assemblage characteristics along environmental gradients and whether these relationships were altered by hypoxic disturbances. We also investigated at what scale dissolved oxygen concentration may be influencing the structure of motile estuarine assemblages and whether the size of the hypoxic zone altered its effects on the estuarine assemblage. Hypoxic disturbances altered fish and crustacean assemblages along the depth gradients that were present during well-oxygenated periods. Species diversity, richness, and catch rates were lower in hypoxic patches than in oxygenated areas. Dissolved oxygen concentration remained an important explanatory variable for patch-level assemblage dissimilarity, species richness, and diversity when data were aggregated across seasons. When we examined the data at a larger scale, by aggregating information across the study area, we did not detect influences of hypoxia on assemblage structure. Fish moved out of local hypoxic zones, but remained within the estuary even in years with extensive hypoxia. There was no effect of size of the hypoxic distrubance on whether organisms responded to hypoxia or on diversity or richness of the study site. These results suggest that these local disturbances play an important role in structuring motile species assemblages at a patch-level within an estuary, but regional factors such as recruitment and migration are important in influencing species assemblages for the entire estuary over months and years.     

记甘肃华池的一件空棘鱼类化石

本文记述了一件产自甘肃华池晚三叠世的空棘鱼类化石,并讨论了陕甘宁盆地中生代早,中期一些含鱼沉积的海相成因及可能与油气生成的关系。     

Numerical studies on lateral load response of fin piles

In the recent past, in order to cater lateral loads, provision of fins to monopiles is evolving as an option for enhancing their lateral load capacity. Numerical and experimental studies pertaining to fin piles subjected to lateral loading are very limited. It is very difficult to understand the behaviour of fin piles through conventional soil pile theories, due to their different fin configurations. In the present study, three-dimensional finite element analyses were performed on regular piles (pile without fins) as well as fin piles. For fin piles, different fin lengths, orientation and position were considered during the analyses. The results have shown that fins placed at the top portion of the piles are more effective than fins placed at bottom of the pile. In all cases, fin piles exhibited more lateral load-carrying capacity compared to regular piles. When fin’s length is less than half of the pile length, lateral load-carrying capacity of fin piles is same irrespective of their orientation. However, fin’s orientation is significant, when fin length is more than 0.5 times length of piles, star fin piles exhibit more lateral load-carrying capacity compared to diagonal and straight fin piles. Fin piles experienced less bending moment compared to regular piles for a given lateral load. Further, it was also noticed that lateral load-carrying capacity of the fin piles depend upon fins’ length and their orientation.     

Tidal Habitats Support Large Numbers of Invasive Blue Catfish in a Chesapeake Bay Subestuary

The introduction of a non-native freshwater fish, blue catfish Ictalurus furcatus, in tributaries of Chesapeake Bay resulted in the establishment of fisheries and in the expansion of the population into brackish habitats. Blue catfish are an invasive species in the Chesapeake Bay region, and efforts are underway to limit their impacts on native communities. Key characteristics of the population (population size, survival rates) are unknown, but such knowledge is useful in understanding the impact of blue catfish in estuarine systems. We estimated population size and survival rates of blue catfish in tidal habitats of the James River subestuary. We tagged 34,252 blue catfish during July–August 2012 and 2013; information from live recaptures (n = 1177) and dead recoveries (n = 279) were used to estimate annual survival rates and population size using Barker’s Model in a Robust Design and allowing for heterogeneity in detection probabilities. The blue catfish population in the 12-km study area was estimated to be 1.6 million fish in 2013 (95% confidence interval [CI] adjusted for overdispersion: 926,307–2,914,208 fish). Annual apparent survival rate estimates were low: 0.16 (95% CI 0.10–0.24) in 2012–2013 and 0.44 (95% CI 0.31–0.58) in 2013–2014 and represent losses from the population through mortality, permanent emigration, or both. The tagged fish included individuals that were large enough to exhibit piscivory and represented size classes that are likely to colonize estuarine habitats. The large population size that we estimated was unexpected for a freshwater fish in tidal habitats and highlights the need to effectively manage such species.     

Assessment of mercury contamination and human exposure associated with coastal disposal of waste from a cinnabar mining operation, Palawan, Philippines

 An integrated geochemical and toxicological assessment of environmental mercury contamination and attendant human exposure in Honda Bay, Palawan was undertaken in 1995 following a nationally reported pollution scare centered on a coastal jetty, Sitio Honda Bay, constructed using approximately 1 million tons of tailings and beneficiation waste from a cinnabar mine. Mercury (Hg) data for marine and fluvial sediments, fish tissues and human hair indicate that the toxicological hazard is considerably lower than initially reported by state environment and health officials. Typical Hg concentrations in surficial Honda Bay sediments were found to lie within the global background range (<60 μg/kg). Downcore profiles provide no evidence of enhanced Hg fluxes coincident with the onset of mining and/or coastal tailings disposal. The mean and median Hg concentrations recorded in tissues of six species of Honda Bay fish are compliant with thresholds established by the US Environmental Protection Agency (US-EPA) for marketable stocks. Earlier reports of 'Minamata range' Hg concentrations in fish and shellfish from Honda Bay remain unsubstantiated. Geochemical analyses of samples of the Sitio Honda Bay substrate have confirmed the prevalence of solid-phase Hg concentrations to ca. 340 mg/kg. The speciation of Hg is, however, dominated by secondary oxides of low bioavailability. The mean Hg concentration in hair from Sitio Honda Bay residents (4.41 mg/kg) was found to be statistically analogous to that for a neighbouring coastal community unimpacted by the coastal disposal of mine waste. A negligible residential exposure factor is thus inferred for the former. Relatively high hair Hg burdens prevail throughout the coastal Honda Bay population, consistent with significant methyl Hg ingestion through daily fish consumption. The data presented provide no environmental or toxicological justification for immediate remedial action. Received: 14 May 1998/Accepted: 1 September 1998     

Spreading change of Africa–South America plate: insights from space geodetic observations

The results derived from geological data show that the half-spreading rate between the African and South American plates has remained relatively constant at 2 cm/year over the past 80 million years (Silver et al. in Science 279:60–63, 1998). In this paper, we have reestimated a new relative angular velocity of Africa–South America plates using the selected space geodetic station data through a new method. Our angular velocity estimates the spreading rates of Africa–South America plate over several years that are similar in azimuth but significantly slower in rate than the NUVEL-1A predictions averaged over the past 3 million years. The implied rates of deceleration coincide with longer-term trends over the past 35 million years and may reflect the effects of plate interaction and coupling of Africa–South America plates. An erratum to this article can be found at