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1.
The species of the genus Discogobio (Teleostei: Cyprinidae) inhabiting the Wenshan prefecture (branches of upper Red River) of Yunnan Province, China are reviewed. The authors recognize four species from the prefecture, Discogobio antethoracalis n. sp., Discogobio propeanalis n. sp., Discogobio poneventralis n. sp., and D. yunnanensis. D. antethoracalis and D. propeanalis had previously been identified as Discogobio brachyphysallidos. D. antethoracalis can be distinguished from D. brachyphysallidos by the following characters: snout rounded, not projected (versus slightly pointed, projected); head length 17.5–20.6% of SL (vs. 20.8–22.8); prepectoral length 16.3–18.3% of SL (vs. 19.1–22.0); interorbital width 52.5–60.9% of head length (vs. 44.7–50.0); anus to anal-fin origin distance 25% posterior end of pelvic-fin base to anal-fin origin distance (versus less than 25). D. propeanalis can be distinguished from D. brachyphysallidos by the following combination of characters: interorbital width greater than half of head length (versus less than half); pelvic-fin extending beyond anal-fin origin (versus not reaching anal-fin origin); anus closer to anal-fin origin, anus to anal-fin origin distance less than 25% posterior end of pelvic-fin base to anal-fin origin distance (versus more than 25%). D. poneventralis, with a small oral sucking disc (its posterior edge not reaching vertical of anterior margin of eye) is similar to Discogobio longibarbatus and D. macrophysallidos, but distinct from them in the following characters: rostral barbels equal to eye diameter (versus twice as long as eye diameter in D. longibarbatus); maxillary barbels not reaching posterior margin of oral sucking disc (versus beyond in D. longibarbatus); mid-ventral region anterior to pelvic-fin insertion scaleless (versus scaled in D. macrophysallidos); prepelvic length 57.1–58.1% of SL (vs. 52.4–55.6 in D. macrophysallidos); pectoral-pelvic length 40.8–41% of SL (vs. 32.6–35.9 in D. macrophysallidos); head length 17.5–18.4% of SL (vs. 19.8–21.8 in D. macrophysallidos); and snout length 44.9–47.2% of HL (vs. 48.9–55.4 in D. macrophysallidos).  相似文献   

2.
Length‐weight relationships of three sympatric species of stingrays from a coastal mudflat, Malaysia were estimated. A total of 290 individuals (150 Himantura walga, 78 Dasyatis bennetti, and 57 Dasyatis zugei) were sampled using barrier net, gill net and beam trawl. The length‐weight relationship based on disc length and width generally showed positive allometric growth (b > 3) for all species. This study reports the first findings regarding the length‐weight relationships of these stingray species in Malaysian waters.  相似文献   

3.
Ophiotaenia bungari n. sp. (Cestoda: Proteocephalidea) is described from the intestine of the banded krait Bungarus fasciatus (Schneider) (Ophidia: Elapidae) in Vietnam. The new species differs from all but three Ophiotaenia species parasitic in Asian reptiles in the possession of a glandular apical organ. It differs from O. andersoni Jensen, Schmidt & Kuntz, 1983 in the position of the vagina in relation to the cirrus-sac (anterior and posterior in O. bungari versus anterior only in the latter species), in the cirrus-sac/proglottis width ratio (29–38 versus 50%) and by having more testes (100–150 versus 42–116 in O. andersoni); from O. chattoraji Srivastava, 1980 in the number of uterine diverticula (50–65 versus 10–26) and in the cirrus-sac/proglottis width ratio (29–38 versus 22%); and from O. rhabdophidis (Burt, 1937) by having more uterine diverticula (50–65 versus 30–45), by the cirrus-sac/proglottis width ratio (29–38 versus 20–25%) and by the width of the scolex (360–420 versus 130–187 μm). The taxonomic importance of the relative size of the ovary (i.e. the ratio of the ovarian size in relation to that of the entire proglottis), a character previously not used in the systematics of proteocephalidean cestodes, is discussed. Comparison of measurements of all of the nominal species of Ophiotaenia La Rue, 1911 and Proteocephalus Weinland, 1858 (c.135 species) has shown that the ovary of species parasitic in snakes in the Americas, Africa, Asia and Australia is not only considerably smaller than that of congeneric species from European hosts, but also smaller than in all species of Proteocephalus parasitic in teleost fishes throughout the world.  相似文献   

4.
A new species of opisthoproctid, Dolichopteryx pseudolongipes, is described on the basis of three specimens (48.7–79.9 mm in standard length: SL) collected from the eastern Pacific Ocean. This species is characterized by small tubular eyes (diameter 2.7–3.9% SL), presence of an adipose fin, anal fin base originating under the dorsal fin base, relatively short predorsal (73.3–73.8% SL), prepelvic (64.3–67.9% SL), preanal (77.4–80.1% SL), and preanus (71.5–75.7% SL) lengths; 31–33 (=9–10 + 22–24) gill rakers and 43–45 vertebrae. Although D. pseudolongipes had previously been confused with Dolichopteryx longipes, many differences between the species are apparent [e.g., adipose fin absent, anal fin base origin just behind dorsal fin base, greater prepelvic length (70.3–72.7% SL), 25 gill rakers, and 46–47 vertebrae in D. longipes].  相似文献   

5.
For the systematic study of the gonostomatid fishes of theDiplophos taenia species complex, a total of 698 specimens was obtained from the three oceans. Four valid species were recognized:D. taenia Günther,D. proximus Parr,D. orientalis Matsubara, andD. australis sp. nov. The diagnostic characters are 90–100 total vertebrae (TV) (37–41 abdominal (AV) +52–60 caudal vertebrae (CV)) and 103–115 IC photophores (IC) for D.taenia, 85–90 TV (36–39 AV + 48–52 CV) and 98–104 IC forD. proximus, 83–86 TV (33–35 AV + 49–52 CV) and 92–100 IC for D.orientalis, and 84–91 TV (33–37 AV+ 50–54 CV) and 99–105 IC forD. australis. In addition to the above,D. proximus has larger orbital diameter (the proportion to head length 21–28%) than the other three species (15–23%) beyond 70mm in standard length. Due to wide distribution,D. taenia shows meristic variations: the numbers of TV, IC and anal fin rays (A) are smaller at lower latitudes and larger at higher ones in all oceans, and the number of A is smaller in the Atlantic (56–71) than in the other oceans (59–72) of the same latitude. Because of these variations, identification to species level is possible only area by area. The distribution of each of the four species is also distinct:D. taenia is a cosmopolitan between about 40° N and 30° S exclusive of the eastern tropical Pacific;D. proximus is endemic to the eastern tropical Pacific;D. orientalis is limited to the North Pacific transitional zone between about 30° and 40° N; andD. australis in a transitional zone of the Southern Ocean south of 20° S.  相似文献   

6.
Two new species of the sciaenid genusJohnius (Johnius) are described:J. trewavasae from Taiwan, Hong Kong, and Singapore, differs from all other congeners in having 24–27 dorsal soft rays, 5–6 scales above and 7–10 scales below the lateral line, 6–8 obtuse lower gill rakers, the last pleural rib on the 11th vertebra, and a shorter lower jaw (33.8–38.4% HL);J. latifrons from Thailand and Java is characterized by 25–29 dorsal soft rays, 7–9 scales above and 11–14 scales below the lateral line, 7–9 obtuse lower gill rakers, a wide interorbital width (26.1–30.6% HL), a small eye (16.7–26.4% HL), and a short, second anal spine (25.9–37.1% HL). Two related species,J. heterolepis Bleeker from “Suriname” andJ. cantori Bleeker from Malaya, are resurrected as valid West Pacific species of Johnius (Johnius).  相似文献   

7.
A new species of the fish genus Grammonus (Ophidiiformes: Bythitidae) is described based on a ripe female, 98 mm in standard length (SL). It was caught at the bottom of a cave at a depth of 20 m under lightless conditions in Ie-shima Island, one of the Ryukyu Islands. A comparison to the seven described species of Grammonus shows the greatest similarity to the widely distributed G. robustus, but G. yunokawai n. sp. differs from it by having fewer vertebrae (41 vs. 44–47), a greater predorsal length (41.5 vs. 32.0–39.0% SL), higher posterior margin of maxilla (8.4 vs. 5.6–7.3% SL), and greater interorbital width (10.5 vs. 5.9–7.6% SL). Supplementary material to this paper is available in electronic format at  相似文献   

8.
We were interested in whether the contrasting regional distribution patterns of three congeneric, frequently co-occurring fern species (Dryopteris carthusiana, D. dilatata and D. expansa) could be explained by differential biomass allocation strategies and different phenotypic plasticities to light availability. The morphology and habitat preference of these ferns are known to be very similar, but in Estonia, their frequencies of occurrence differ sharply––Dryopteris carthusiana is common, D. expansa grows in scattered localities, and D. dilatata is rare. We grew the species under different levels of illumination (100, 50, 25 and 10% of full daylight) in an experimental garden to compare their autecological responses to shading. After one growing season there were clear interspecific differences in total plant biomass accumulation––D. carthusiana > D. expansa > D. dilatata––indicating the possible competitive inferiority of the latter at the young sporophyte stage. D. expansa was the least shade-tolerant, with biomass decreasing sharply under less than 50% illumination; D. dilatata was the most shade-tolerant, with similar growth at all illumination levels. In relative biomass allocation patterns, the most notable differences among species were in the relative shares of biomass stored in rhizomes. In D. carthusiana and D. expansa this share was nearly constant and independent of the illumination conditions. D. dilatata allocated very little biomass into rhizome in deep shade, but was able to increase this share more than twofold in 50% light. Dryopteris dilatata was clearly shown to be morphologically the most plastic of the three. In four traits––rhizome mass, frond:below-ground biomass ratio, stipe length and specific leaf area––its degree of ontogenetic plasticity to light was significantly higher than that of D. expansa and D. carthusiana. While the general performance (biomass production) of species in the experiment coincided with that observed in nature, the results of plasticity estimation were somewhat surprising––it is difficult to explain the inferior performance of a species (D. dilatata) through high morphological plasticity. Probably, the species is rare either because of certain climatic restrictions, or because it is presently expanding its distribution and is in the phase of invading Estonian understory communities.  相似文献   

9.
A new species of genus Microrasbora Annandale (1918), M. microphthalma, is described from the Nanwan River, a tributary of the Ruili River, Irrawaddy drainage, in southwest Yunnan province, China. This new species is the first record of the genus Microrasbora in China. Microrasbora microphthalma can be distinguished from the other species of Microrasbora by the following combination of characters: 15–16 predorsal scales, eye diameter/head length 27–38%, eye diameter/interorbital width 70–93%, predorsal length/ standard length 60–68%, the preanal length/ standard length 65–71% and the origin of dorsal fin is posterior of that of the ventral fin. Xiao-Yong Chen and Jun-Xing Yang contributed equally to this paper.  相似文献   

10.
Channa nox, a new channid fish lacking a pelvic fin from Guangxi, China   总被引:1,自引:1,他引:0  
 A new species of channid fish, genus Channa, is described from 7 specimens collected from the vicinity of Hepu, Guangxi Province, southern China. The new species, Channa nox, is distinguished from all other channid species by the following combination of characters: absence of pelvic fins, small rounded head (22.1%–26.8% SL), narrow interorbital width (19.6%–26.7% HL), short snout length (3.6%–5.1% SL), predorsal and prepectoral lengths (26.9%–28.4% SL and 24.8%–28.3% SL, respectively), 47–51 dorsal fin rays, 31–33 anal fin rays, 55–63 lateral line scales, 5.5–6.5 scales above lateral line, 9–13 cheek scales, 53–55 total vertebrae, 1 or 2 scale(s) on each side of lower jaw undersurface, the black upper half of body with 8–11 irregular (often anteriorly pointed V-shaped) bands or blotches, a large white-rimmed black ocellus on caudal peduncle and sparse white spots on the dark brown body and dorsal and caudal fins, as well as the shape of the hyomandibular process of the suprabranchial organs. Channa nox is sympatrically distributed with its morphologically most similar congener, C. asiatica. Received: January 18, 2001 / Revised: November 2, 2001 / Accepted: December 12, 2001  相似文献   

11.
A new sciaenid,Johnius (Johnius) laevis, is described from northern Australia and Papua New Guinea. Amongst theJohnius (Johnius) species with no mental barbel, ctenoid body scales, and more than 10 lower gill rakers, the new species is distinguished by the combination of the following characters: dorsal soft rays 29–34; scales above the lateral line 5–6, and below 8–10; eye diameter 22.4–30% HL; interorbital width 24.6–29.8% HL; and body scales with weakly developed ctenii.  相似文献   

12.
Essential oil of the subterranean part of Cacalia tangutica (Maxim.) Hand.-Mazz was analyzed by gas chromatography (GC)-mass spectrum (MS) technique in two different capillary columns of different polarities. Thirty-one components were identified in the oil and the main compounds were α-zingiberene (13.49%), germacrene D (10.76%), α-pinene (8.54%), caryophyllene(Z-) (6.36%), linalool (6.16%), β-myrcene (4.89%), β-ocimene (Z-) (4.40%)and ocimenone(Z-) (3.58%). The antimicrobial activity of the oil was evaluated against 2 fungi and 12 bacteria including 6 clinically isolated strains using the agar disc diffusion and broth microdilution methods. The results show that the oil presented a broad antimicrobial spectrum and had better antimicrobial activity against yeast and gram-positive bacteria. The minimum inhibitory concentration values were 0.16–5.00 g/L and minimum bactericidal concentration values were 0.16–5.00 g/L. __________ Translated from Journal of Wuhan University (Science Edition), 2007, 53 (2): 198–203 [译自: 武汉大学学报(理学版)]  相似文献   

13.
Daphnid morphology deters fish predators   总被引:3,自引:0,他引:3  
Spine and helmet production in zooplankton are thought to provide protection from invertebrate rather than vertebrate predators. We examined selectivity for Daphnia lumholtzi, a species that exhibits extreme cyclomorphosis with a large helmet and long tail spine (total length can exceed 5 mm), by juvenile bluegill (15–80 mm) in the laboratory and field. Bluegill consumed more D. pulex than D. lumholtzi when the species were presented alone. When the daphnids were offered together in equal numbers, bluegill selected against D. lumholtzi. Bluegill foraging behavior helped explain the observed nonrandom feeding. Bluegill capture efficiency foraging on D. pulex was high (85–100%) and handling times were low (usually too short to detect), whereas efficiencies were lower (40–96%) and handling times were longer (1–3 s) when foraging on D. lumholtzi, particularly for fish <50 mm. As they gained experience, bluegill <50 mm that oriented towards D. lumholtzi rejected them more often than striking. In addition, more D. lumholtzi were rejected and expelled than were D. pulex. From these experiments, we conclude that larger bluegill (>50 mm) are able to forage more successfully on D. lumholtzi than smaller fish. Selectivity by bluegill collected from a reservoir infested with D. lumholtzi verified our laboratory conclusions. Smaller bluegill selected against D. lumholtzi, whereas it was a preferred diet item for bluegill >50 mm. These results show that the morphology of D. lumholtzi interferes with predation by small planktivorous fish, posing foraging constraints for these fish more similar to those of piscivores, where handling time is important, than to those of planktivores, where prey density is of primary importance. Received: 13 August 1998 / Accepted 21 August 1998  相似文献   

14.
Survivorship and growth of seedlings of four dipterocarp species (Dipterocarpus actangulus, D. globosus, Dryobalanops aromatica, Dryobalanops lanceolata) were studied for 2.5 years in a mixed dipterocarp forest in Sarawak, East Malaysia. Predispersal seed predation rates were larger forD. globosus (75%) thanD. lanceolata (27–34%) andD. aromatica (18–26%). Less than 20% of the twoDryobalanops seeds were damaged by vertebrates after seed dispersal. During the period from seed dispersal to the time when the seedlings had shed cotyledons, more dispersed seeds died in the twoDipterocarpus (ca 90%) than the twoDryobalanops (ca 60–70%). The major mortality factors during this period were uprooted and seed/seedling predation by insects or vertebrates. After the seedlings shed cotyledons, all species showed constant mortality rates of 34, 15–16, 17 and 6%/year forD. actangulus, D. lanceolata, D. aromatica andD. globosus, respectively, in the forest understorey. Mortality was lower in less shaded conditions than in more shaded ones forD. aromatica andD. actangulus, but not significantly different forD. lanceolata andD. globosus. A majority of dead seedlings were killed by fallen branches or were found standing with wilted leaves, probably due to water stress. No significant correlation was found between seed/seedling mortality and distance from mother trees or the initial density of seeds/seedings for all species. The mean leaf production was positively correlated with the estimated diffuse light factor of their habitats for each species.  相似文献   

15.
A new species of the genus Glyptothorax, Glyptothorax obliquimaculatus sp. nov. is described from the Xiaohei River, a tributary of the Nanting River, Salween drainage, in southwestern Yunnan province, China. This new species can be distinguished from its congeners by the following combination of characteristics: unculiferous ridges of the thoracic adhesive apparatus extending anteriorly onto the gular region; body with irregular dark blotches scattered along lateral surface (blotches mostly oblique); skin smooth on head and body; dorsal spine smooth without serrations on its posterior margin; lips smooth; posterior margin of pectoral spine with 7–8 serrations; dorsal-fin base 11.0–13.2% SL; pectoral-fin length 15.6–19.6% SL; depth of caudal peduncle 8.6–9.8% SL; head width 19.1–24.0% SL; nasal barbel length 23.3–33.3% HL.  相似文献   

16.
The composition of the essential oil from the wormwood sage (Artemisia frigida Willd., Asteraceae) of populations growing in the Altai Territory, the Altai Republic, the Khakass Republic, the Tuva Republic, and the East-Kazakhstan region of the Republic of Kazakhstan and the representative species of the silver-leaved wormwood Artemisia argyrophylla Ledeb. growing in the Republic Altai has been studied by chromato-mass spectrometry. An analysis of 15 samples of the essential oil from A. frigida obtained over a period from 1999 to 2007 indicates that samples from different populations have similar sets of the main components: α-pinene (0.2–7.8%), camphene (1.9–5.8%), 1,8-cineole (8.9–33.8%), camphor (6.7–40.0%), borneol (3.9–12.3%), terpine-4-ol (1.5–6.5%), bornyl acetate (1.4–22.0%), and germacrene D (1.4–14.6%). Some samples contain substantial amounts of α- and β-thujones (in total up to 19.1%), which are completely absent in other samples. Some samples contain santolina alcohol (up to 13.8%) and its acetate (up to 4.8%). As differentiated from A. frigida, the essential oil of A. argyrophylla contains yomogi alcohol (1.2%), artemisia ketone (12.9%), artemisia alcohol (3.1%), artemisia alcohol acetate (3.9%), and small amounts of camphor (3.2%), borneol (0.3%), and bornyl acetate (0.2%).  相似文献   

17.
We examined the effects of temperature and photoperiod on metabolic thermogenesis and the thermogenic characteristics of brown adipose tissue in plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus), the dominant species of small mammals in the alpine meadow ecosystems on the Qinghai-Tibetan Plateau. Pikas and voles were acclimated in the following groups: (1) Long day – warm temperature (16L:8D, 23 °C), (2) Long day – cold temperature (16L:8D, 5 °C), (3) short day – warm temperature (8L:16D, 23 °C), and (4) short day – cold temperature (8L:16D, 5 °C). Both temperature and photoperiod were important environmental cues for changes in thermogenesis for both species. Low temperature and short photoperiod induced increases in metabolic rate, nonshivering thermogenesis (NST), mitochondrial protein contents of brown adipose tissue, and cytochrome C oxidase activity of brown adipose tissue mitochondria in both species. Plateau pikas were more sensitive to cold (79% of the total NST response) than to short photoperiod (21%), while root voles were more sensitive to short photoperiod (60% of the total NST response) than to cold (40%), although cold clearly enhanced thermogenesis. Their thermogenic characteristics correlated with their preferred habitats: plateau pikas are found mainly in more exposed microhabitats in open sunny meadow, while root voles live in more sheltered microhabitats in relatively closed shrub. Our results also showed that temperature and photoperiod combined induce thermogenic adjustments in both species in seasonal acclimatization in their alpine meadow macrohabitat. Accepted: 10 November 1998  相似文献   

18.
 The fatty acid compositions of the seed oils from ten pine species have been established by capillary gas-liquid chromatography of the methyl esters. With regard to either normal fatty acids or Δ5-olefinic acids, the general pattern of fatty acids did not differ from that of other pine seed oils reported previously. The main fatty acid was linoleic (9,12–18:2) acid (44.4–57.1%), followed by either oleic (9–18:1) acid (13.4–24.5%) or pinolenic (5,9,12–18:3) acid (1.5–25.2%). When applying multivariate analyses to the chemometric data (13 variables) of 49 pine species (ca. 40% of the living pine species), it was possible to distinguish between several sections: Pinea, Longifolia, Halepensis, Ponderosa-Banksiana, Sylvestris, and Cembra. The latter section was clearly divided into two sub-groups. A few species that presented a low overall content of Δ5-olefinic acids, and that grow in warm-temperate regions, were isolated from the bulk of other pine species. It is hypothesized that Δ5-olefinic acids might be related to cold-acclimation. Received: 5 June 1997 / Accepted: 17 August 1997  相似文献   

19.
The sex pheromones of two species of hawk moth, Deilephila elpenor lewisii (Butler) and Theretra oldenlandiae oldenlandiae (Fabricius), were analyzed using gas chromatography–electroantennographic detection (GC–EAD) and GC–mass spectrometry (GC–MS). Two and three EAD-active components were found in D. elpenor lewisii and T. oldenlandiae oldenlandiae, respectively. GC–MS analyses using authentic compounds and extracts derivatized by dimethyl disulfide and 4-methyl-1,2,4-triazoline-3,5-dione identified the two components in D. elpenor lewisii as (E)-11-hexadecenal (E11–16:Ald) and (10E,12E)-10,12-hexadecadienal (E10,E12–16:Ald), and the three in T. oldenlandiae oldenlandiae as E11–16:Ald, E10,E12–16:Ald, and (10E,12Z)-10,12-hexadecadienal (E10,Z12–16:Ald). In field-trap tests, no males of either species were attracted to any single components. Male moths of D. elpenor lewisii were specifically attracted to a binary blend of E11–16:Ald and E10,E12–16:Ald at a ratio of 85:15, whereas males of T. oldenlandiae oldenlandiae were attracted to a ternary blend of E11–16:Ald, E10,Z12–16:Ald and E10,E12–16:Ald at a ratio of 30:40:30. We therefore conclude that the sex pheromone of D. elpenor lewisii is a mixture of E11–16:Ald and E10,E12–16:Ald and that of T. oldenlandiae oldenlandiae is E11–16:Ald, E10,Z12–16:Ald and E10,E12–16:Ald.  相似文献   

20.
A new species of softnose skate (Arhynchobatidae) is described, based on a single adult male measuring 895 mm TL that was collected at a depth of 953–1,022 m on the Coriolis Bank off western New Caledonia in the southwestern Pacific Ocean. The specimen conforms to the genus Bathyraja in having the rostral cartilage continuous with the neurocranium and very slender and uncalcified over its length. Bathyraja leucomelanos sp. nov. differs from its congeners through a combination of the following characters: distinctive coloration of the disc with white dorsal and black ventral surfaces, dorsal surface of the disc entirely covered with dermal denticles, ventral surface naked, anterior portion of the anterior margin of the disc straight, snout long and very broad with orbit about 6.0 times in preorbital length, orbit 0.73 times interorbital width, mouth 6.8% TL, tail 0.88 times precloacal length, accessory terminal 2 cartilage of the clasper having an expanded disc-shaped tip, and alar thorn tip undulating. Molecular barcoding from the COI sequence reveals that this new species is genetically close to B. spinicauda from the North Atlantic Ocean.  相似文献   

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