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1.
Hoplitomeryx Leinders was originally described only on cranial characters. The type specimens were found during the 1970's in karstic fissure fillings, most likely of Messinian age, in Gargano (Apulia, southeastern Italy), between Poggio Imperiale (41°49′30′ N, 15°21′58′ E) and Apricena (41°47′06′ N, 15°26′41′ E). During the 1990's, Hoplitomeryx remains were also discovered in the lower Tortonian layered calcarenites near Scontrone (Abruzzo, central Italy; 41°45′15.55′ N, 14°02′13.23′ E). The skull fragments, teeth, and jawbones from both localities have been examined. The dental characters had never been described before, and also some maxillaries and jawbones were not part of the original sample that was analyzed to establish the genus. Because they possess two lacrimal orifices and closed metatarsal gulley, hoplitomerycids have been linked more closely with Cervids, and accommodated in Cervoidea. A cladistic analysis of a character-taxon matrix of 121 morphological features (48 cranial, 51 dental and 22 postcranial characters) is performed. The analysis shows that hoplitomerycids stem either between antilocaprids and bovids, or antilocaprids and giraffids. They are not linked directly with cervids. Hoplitomerycids likely stemmed from a primitive ruminant stock, perhaps around 29 Ma when a land bridge connected the Abruzzo-Apulia platform with the Balkans across the Adriatic Sea. In the new land, hoplitomerycids developed a mosaic of apomorphic and homoplastic (convergent) character states that recall those found in other higher ruminants.  相似文献   

2.
The size and sex compositions, spawning period, and length at sexual maturity of the gilt sardine Sardinella aurita dwelling in the Central Eastern Atlantic in the area of 15°31′–26°32′ N and 14°09′–17°50′ W were examined from material of many years (1968–2004). The age and rate of linear growth and the relation of length and weight were determined.  相似文献   

3.
Evidence on occurrence in catches and characteristic of the spatial-bathymetric distribution and size indices of four species of Cottidae—frog sculpin Myoxocephalus stelleri, brightbelly sculpin Microcottus sellaris, antlered sculpin Enophrys diceraus, and furseal sculpin Stelgistrum stejnegeri—in summer-autumn months in the Okhotsk Sea waters off Kamchatka (site from 51°15′ to 57°20′ N, depths of 11–100 m) are provided. The first three species occur mainly in the northern part of the shelf above 54° N at depths smaller than 30–40 m within a comparatively well warmed surface water mass of seasonal modification at near-bottom temperature values above 6°C at various solid grounds. Maximum catches of S. stejnegeri were recorded only at a site of the western Kamchatka shelf from 54°00′ to 54°20′ N on pebbly-stony ground in a narrow bathy-metric range of 41–60 m on the boundary between the well warmed surface water mass of autumn modification and the cold intermediate water mass at a water temperature below 2°C. Evidence on the size-weight indices of the studied species of Cottidae in trawl catches in the Okhotsk Sea waters off Kamchatka in the study period is provided.  相似文献   

4.
In the Black Sea, the sea anemone Sagartia elegans (Dalyell, 1848) has been found for the first time in the Gulf of Odessa (46°31′60 N, 30°48′ E) and karst caves and grottos of the Western Crimea (45°21′ N, 32°30′ E). Previously, S. elegans was known to inhabit coastal waters of Iceland, the British Isles, and continental Europe from Scandinavia to the Adriatic Sea. According to the available data, this gonochoristic species tends to asexual somatic reproduction through laceration: juvenile polyps develop from separated fragments of the pedal disc. A rich color polymorphism is observed. The numerous clonal populations that are found in caves consist of variously sized and similarly colored polyps. All of them descended from one parental individual.  相似文献   

5.
Intertidal Ulva mats occur annually in winter and spring in the Xiangshan Bay (29°26′–29°34′ N, 121°27′–121°50′ E) of China. Thousands of tons of Ulva biomass have been harvested as edible seaweeds for human consumption for several decades in this region. This investigation was designed to quantify Ulva microscopic propagules associated with the mat, identify species composition, and to analyze intra-species relationships using three molecular markers. Phylogenetic analysis based on the nuclear encoded rDNA internal transcribed spacer region, the plastid encoded large subunit of the ribulose 1,5-bisphosphate carboxylase gene, and the 5S rDNA spacer region showed that the mat was principally composed of Ulva prolifera and Ulva flexuosa. Their propagules were detected in both the water column and sediment. Based on phylogenetic analyses of the 5S rDNA spacer region, mat samples of U. prolifera and U. flexuosa were genetically distinct from the green tide samples in the Yellow Sea and U. flexuosa samples from Jiangsu coasts, respectively, revealing that isolated geographical position of the Xiangshan Bay might result in the maintenance of a distinct Ulva population. The results demonstrate that high-resolution DNA markers have great potential in identification and discrimination at and below the species level.  相似文献   

6.
The horizontal and vertical distributions of two species of endemic, burrowing mud crabs Helice crassa Dana 1851 (Grapsidae) and Macrophthalmus hirtipes (Jacquinot 1853) (Ocypodidae) are described for the Avon-Heathcote Estuary (43°33′S: 172°44′E), Christchurch, New Zealand. Substratum preference is shown to be the most important factor influencing mud crab distribution, but lack of tolerance to salinities below 4‰ is also a significant factor preventing M. hirtipes from occurring at points close to freshwater input. Both species had similar sediment organic content and particle size requirements. Helice crassa was concentrated in well-drained, compacted sediments above mid-tide level, whilst Macrophthalmus hirtipeswas found in waterlogged areas below mid-tide level. This vertical separation is shown not to be caused by differential desiccation tolerances, but by feeding and burrowing adaptations related to these different substrata.  相似文献   

7.
The first capture of the Greenland (or Black) halibut Reinhardtius hippoglossoides in the Arctic Ocean on the border with the East Siberian Sea (79°03′–79°08′ N 139°59′–141°16′ E, 259–277 m) and the repeated findings of the species in the Laptev Sea (78°03′–78°04′ N 132°56′–133°04′ E, 307 m; 78°33′–78°35′ N 138°44′–138°48′ E, 125 m) are reported. Fish (79 specimens with the length of 15.0–44.5 cm) were caught during four bottom trawlings on the edge of the continental shelf of the two seas in the transformed waters of Atlantic origin, as evidenced by the discovery of the indicator species of these waters—the Glacier lanternfish Benthosema glaciale (Myctophidae)—in one of the stomachs of halibut. The other captures of Greenland halibut in the Arctic were also reviewed.  相似文献   

8.
《Marine Micropaleontology》2009,70(3-4):263-281
Regression analysis was performed between the ratio of warm- and cold-water diatoms (Td′ ratio) in 123 surface sediment samples in the northwest Pacific Ocean and the mean annual sea surface temperatures (SSTs) (°C) at the core sites, in order to calibrate this proxy for paleo-temperatures. Equations to derive annual SST (°C) from diatom analysis were somewhat different for the Tohoku area (y = 6.5711⁎ × 0.273, r = 0.89946) than for the Japan Sea (y = 5.4069⁎ × 0.26841, r = 0.89088). The annual paleo-SSTs (°C) in the Tohoku Area were in general higher than in the Japan Sea despite lower Td′ values, because the warm-water species Fragilariopsis doliolus is abundant only in the Tsushima Warm Current in the Japan Sea. The reliability of the equations is supported by our understanding of the ecology of recent diatoms. Td′-derived annual paleo-SSTs (°C) agree with alkenone-derived summer paleo-SST (°C) at a site off central Japan in the northwestern Pacific. In a south-to-north transect of cores around Honshu and Hokkaido, paleo-SSTs (°C) decreased when the Kuroshio and Tsushima Warm Currents weakened. The middle Holocene (8.2–3.3 cal kyr BP) was warmer by 1–2 °C than earlier and later parts of the Holocene, and mean annual paleo-SSTs (°C) show rhythmic fluctuations with durations of 1000 years and 400–500 years. These new data show that annual SSTs were warm in the northwestern Pacific at times that the northeastern Pacific was cold. In addition, oceanic warm- and cold-water species defined by Kanaya and Koizumi [Kanaya, T., Koizumi, I., 1966. Interpretation of diatom thanatocoenoses from the North Pacific applied to a study of core V20–130 (studies of a deep-sea core V20–130, part IV). Sci. Rep. Tohoku Univ., 2nd series (Geol.) 37, 89–130], and Koizumi et al. [Koizumi, I., Irino, T., Oba, T., 2004. Paleoceanography during the last 150 kyr off central Japan based on diatom floras. Mar. Micropaleontol. 53, 293–365] are illustrated.  相似文献   

9.
The three-dimensional structure was determined by x-ray crystallography for d(T[p](CE)T), a uv photoproduct of the cyanoethyl (CE) derivative of d(TpT), having the cis-syn cyclobutane (CB) geometry and the S-configuration at the chiral phosphorus atom. The crystals of C23H30N5O12P · 2H2O belong to the orthorhombic space group P212121 (Z = 4), with cell dimensions a = 11.596 Å, b = 14.834 Å, and c = 15.946 Å, containing two water molecules per asymmetric unit. The CB ring is puckered with a dihedral angle of 151°. The two pyrimidine bases are rotated by –29° from the position of direct overlap of their corresponding atoms. This represents a major distortion of DNA, since in DNA adjacent thymines are rotated by +36°. The pyrimidine rings are puckered with Cremer–Pople parameters for T[p] and in parentheses [p]T: Q: 0.24 Å (0.31 Å); θ: 123° (120°); ?: 141° (86°). These represent half-chairs designated as 6H1 (T[p]) and 6H5 ([p]T). The CB and pyrimidine ring conformations are interrelated, and we postulate that they execute a coupled interconversion in solution. The T[p] segment has the syn glycosyl conformation, a 2T3 sugar pucker, and gauche? conformation at C4′-C5′; the [p]T segment is anti, 3T4, trans. The C5′-O5′ torsion of the [p]T unit is –124.5°, and the C3′-O3′ torsion of the T[p] unit is –152.9°. Bond angles and bond lengths involving the phosphorus atom are similar to those of other phosphotriesters. The P-O3′ and P-05′ torsion angles are –138.1° and 58.6°, respectively. Several intermolecular (but no intramolecular) hydrogen bonds are found in the crystal.  相似文献   

10.
Four species of Lepidoptera were found on Bolshevik Island, the Severnaya Zemlya Archipelago (the Middle-Siberian Arctic sector). The noctuid Xestia aequaeva (Benjamin, 1934) and the geometrid Psychophora cinderella Viidalepp, 2001 are considered residents, while the pickleworm Gesneria centuriella (Denis et Schiffermüller, 1775) and the plutellid Plutella xylostella (Linnaeus, 1758) were brought to the island by air currents. The records of Xestia aequaeva (78°37′N) and Psychophora cinderella (78°56′N) on Severnaya Zemlya are the northernmost for the families Noctuidae and Geometridae in the entire Palaearctic. The European, Middle-Siberian, and Beringian sectors of the Arctic appear to support two sympatric species of the genus Psychophora. The “last” lepidopterans along the heat gradient in the Northern Hemisphere are Psychophora spp. (including P. cinderella) and Gynaephora groenlandica (Wöcke, 1874). Both may serve as indicators in analysis of long-term climate changes in the Far North. The most important adaptations of Lepidoptera, as well as of other arthropod groups, to inhabiting the polar deserts are polyphagy and the capacity for perennial development, with female flight reduced or absent.  相似文献   

11.
Abstract:Menegazzia wandae Bjerke from Chile is newly described. It is characterized by lacerate soralia that are formed on laminar pustules; the sinuous, rather imbricate lobes with brown-black margins, and the presence of thamnolic acid in the medulla. Apothecia are unknown, and pycnidia are rare. The species is known from Chile between latitudes 38°30′S and 46°40′S.  相似文献   

12.
13.
X-ray diffraction studies have been made on oriented polycrystalline fibres of poly(2′-O-methylcytidylic acid). A form observed at 66% relative humidity has orthorhombic (P212121) symmetry and unit cell dimensions a = 1.58 nm, b = 2.16 nm, c = 1.89 nm (fibre repeat). In this form the molecules are singlestranded, 6-fold (61) helices with a conformation very similar to that observed for polycytidylic acid. Evidently methylation at O-2′ does not necessarily cause a change in the pucker of the sugar ring. Nor are the intermolecular hydroxyl-hydroxyl hydrogen bonds observed in the polycytidylic acid rhombohedral crystal structure necessary to maintain the 6-fold helical symmetry. However, they may be necessary to maintain the symmetry at very high relative humidities where the polycytidylic acid structure is conserved but poly(2′-O-methylcytidylic acid) undergoes a transition to a form in which the rotation per residue is reduced from 60 ° to a value near 50 °.  相似文献   

14.
15.
The widely distributed long-finned pilot whale (Globicephala melas) has been reported off the Chilean coast, from Iquique (20°12′S) south to Navarino Island (55°15′S; 67°30′W), but little is known about its biology or ecology in the region. Here, we report on the prey of this species, identified by stomach content analyses from animals stranded on Holget Islets, Beagle Channel, southern Chile in August 2006. The stomachs of seven individuals (six females and one male) contained cephalopod remains. The prey composition found in these southern Chilean pilot whales was similar to that described in other parts of the world and the Southern Ocean. This is the first report on the feeding habits of this species from Chile.  相似文献   

16.
Flavin-containing monooxygenase (FMO) activity as N,N-dimethylaniline (DMA) N-oxygenation was characterized in microsomes from the smooth dogfish shark (Squalus acathias). DMA N-oxygenase activity from the liver of the dogfish shark was linear with increasing protein content and over 60 min. The optimal temperature for catalysis was 25°C with a 76 percent reduction in activity when incubated at 15°C and 99 percent loss of activity at 45°C. Optimal pH was approximately 9.6. The maximum velocity for DMA N-oxygenase activity was calculated to be 1.3 nmol min−1 mg−1 with an apparent Michaelis constant of 44 μM. Methimazole oxidase activity was also observed in dogfish liver microsomes which was inhibited by trimethylamine (TMA). Inhibition of DMA N-oxygenase activity by TMA and thiobenzamide was competitive, while inhibition by methimazole was not competitive. Western blot analysis indicated a single liver protein from both Squalus and Carcharhinus of approximately 50 kDa that bound to antibodies raised against FMO 2. An attempt was made to purify FMO as methimazole oxidase from the liver of the silky shark. A single peak of about 10-fold purity was observed following passage through two chromatographic media (CM-Sepharose and HA-Agarose). However, no activity was recoverable after the FMO-containing fractions were applied to a 2′5′ ADP-Sepharose column.  相似文献   

17.
According to materials of 1997–2002, the characteristic of the spatial-bathymetric distribution, size and age composition, size and sex structure, and feeding of the Korean flounder Glyptocephalus stelleri in the summer period in waters off Kamchatka in the Sea of Okhotsk (the site from 51°15′ to 57°20′ N, depths of 10–300 m) is given. It is shown that throughout the observation period, maximum catches of this flatfish were constantly observed at two sites of the western Kamchatka shelf (51°20′–53°00′ N and 55°00′–56°00′ N) in the zone exposed to the effect of anticyclonic gyres in the range of depths 101–200 m at the near-bottom temperature below 2°C. Unlike other habitat areas, off the coast of western Kamchatka, G. stelleri in the summer time is quite frequently found at negative temperature values, which is obviously determined by the specifics of thermal conditions of the eastern part of the Sea of Okhotsk. It was established that, in this species of flatfish, sex dimorphism is distinctly pronounced in sizes—males are considerably smaller than females whose relative number among individuals with a length larger than 50 cm reaches 100%. The main items of feeding of G. stelleri at the western Kamchatka shelf in the summer period are oligochaetes.  相似文献   

18.
Coralline algae (Corallinales, Rhodophyta) that form rhodoliths are important ecosystem engineers and carbonate producers in many polar coastal habitats. This study deals with rhodolith communities from Floskjeret (78°18′N), Krossfjorden (79°08′N), and Mosselbukta (79°53′N), off Spitsbergen Island, Svalbard Archipelago, Norway. Strong seasonal variations in temperature, salinity, light regime, sea-ice coverage, and turbidity characterize these localities. The coralline algal flora consists of Lithothamnion glaciale and Phymatolithon tenue. Well-developed rhodoliths were recorded between 27 and 47 m water depth, while coralline algal encrustations on lithoclastic cobbles were detected down to 77 m water depth. At all sites, ambient waters were saturated with respect to both aragonite and calcite, and the rhodolith beds were located predominately at dysphotic water depths. The rhodolith-associated macrobenthic fauna included grazing organisms such as chitons and echinoids. With decreasing water depth, the rhodolith pavements were regularly overgrown by non-calcareous Polysiphonia-like red algae. The corallines are thriving and are highly specialized in their adaptations to the physical environment as well as in their interaction with the associated benthic fauna, which is similar to other polar rhodolith communities. The marine environment of Spitsbergen is already affected by a climate-driven ecological regime shift and will lead to an increased borealization in the near future, with presently unpredictable consequences for coralline red algal communities.  相似文献   

19.
《Inorganica chimica acta》1987,132(2):167-176
The 1:1 adducts between thebis(3,5-dimethylpyrazol-1-yl)methane (L′-L′) or 2,2′-bis(pyrazol- 1-yl)propane (L″L″) ligand and HgX2 (with X = Cl, CN or CO2CF3) have been obtained as well as [(L′L′)2]Hg(ClO4)2 and the mercury(I) derivative (ligand)2Hg2(ClO4)2. The adducts have been characterized from analytical and spectral data (IR, proton and 13C NMR). Four-coordinated mercury is present in (L′L′)Hg(CN)2, in which the metal-(NN)2C ring adopts an asymmetric boat form. The molecular parameters are significantly different for the two independent molecules, the CHgC angles and the two Hg-N distances being 163.1(9)°and 2.55(1) plus 2.70(1) Å in the one case, and 148.2(8)° and 2.40(1) plus 2.51(1) Å, in the other; correspondingly the N-Hg-N angle, the ‘bite’ of the ligand, ranges from 79.0(5)° to 71.7(4)°, a value outside the range previously reported.  相似文献   

20.
The Antarctic marine environment is extreme in its low temperatures and short periods of primary productivity. Invertebrates must therefore adapt to maximise reproductive output where low temperature and limited food slow larval development. Brooding is a common reproductive trait in Antarctic marine bivalves; larval development occurs within the mantle cavity, and larvae are released as fully developed young. Lissarca miliaris is a small, short-lived, shallow-water brooding bivalve of circum-Antarctic distribution and found most abundant in the sub-Antarctic Magellan Region and islands of the Scotia Arc. Here, an unusual hermaphrodite reproductive trait is described for L. miliaris from King George Island (62°14′S, 58°38′W) and Signy Island (60°42′S, 45°36′W), Antarctica, using histological and dissection techniques. Specimens demonstrate simultaneous and sequential hermaphrodite traits; male and female gonads develop simultaneously, but the production of oocytes is reduced while testes are ripe. Functional females are more abundant in specimens above 3 mm shell length, although male reproductive tissue persists and functional males are found in all size classes. The number of previtellogenic oocytes produced by far exceeds the number of oocytes extruded and brooded, which may indicate an ancestral link to a planktotrophic past. Hermaphroditism in L. miliaris maximises reproductive efficiency in a short-lived species, in which the female’s capacity to brood its young is limited, and demonstrates a specialised adaptation to a cold stenothermal and food-limited environment prevailing in the Southern Ocean.  相似文献   

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