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Early life stages of Artedidraco skottsbergi and A. shackletoni were collected off Adélie Land. The morphology and pigmentation pattern of nine larvae and juveniles of A. skottsbergi between 17.2 and 21.4 mm in standard length (SL), and of two juveniles of A. shackletoni measuring 25.1 mm SL were described. A. skottsbergi was characterized by a heavily pigmented body, except for the caudal peduncle, with distinctively dense pigmentation on the
ventrolateral half of the body and caudal section (17.2–17.9 mm SL). Furthermore, they had no pigmentation on the pectoral
fin base until they attained 21.4 mm SL. Juvenile A. shackletoni had a heavily pigmented body except for the ventral side of the abdomen and the anal fin base. The proximal part of the dorsal
fin and most of the anal fin were covered with melanophores. Although knowledge of larval and juvenile Artedidraco species is limited, the distribution of melanophores on the fins, pectoral fin base and caudal peduncle at each developmental
stage may be useful for species identification. 相似文献
3.
Makoto Okamoto 《Ichthyological Research》2011,58(2):101-108
A new epigonid fish, Epigonus mayeri, is described on the basis of two specimens (109.7–113.8 mm in standard length: SL) from off Angola, and Epigonus heracleus Parin and Abramov 1986 is redescribed on the basis of 12 additional specimens with type specimens from off eastern New Zealand.
These species belong to a subgroup of Epigonus, known as the “Epigonus robustus group,” which have a pungent opercular spine and VII-I, 9 dorsal-fin rays. The new species differs from other species of
the group by having a sharp-pointed mustache-like process, presence of a rib on the last abdominal vertebra, vertebrae 10 + 15,
tongue toothless, pyloric caeca 5, pectoral fin reaching to vertical line from anus (length 22.2–23.6% SL), orbital diameter
16.4–17.0% SL, head length 37.8–38.0% SL, and lower jaw length 16.7–17.0% SL. 相似文献
4.
Synopsis Feeding ecology was compared between sympatric greenling species, Hexagrammos otakii and H. agrammus in the eelgrass beds in Jindong Bay, Korea, from January to December. These two species had similar diets composed of crustaceans,
polychaetes, gastropods and fishes; both species consumed primarily crustaceans throughout study periods. H. otakii, however, fed a greater proportion of polychaetes and fishes than H. agrammus. H. agrammus had a greater proportion of gastropods in their diets. The diet of both species underwent size-related changes; smaller individuals
of H. otakii and H. agrammus consumed amphipods (gammarid amphipods and caprellid amphipods), while larger individuals of H. otakii ate polychaetes and fishes and those of H. agrammus fed mainly on gastropods and crabs. The diet of H. otakii underwent seasonal changes; H. otakii consumed mainly polychaetes and fishes during January and February 2002 but amphipods during March and May 2002. H. agrammus, however, ate mainly gastropods and crabs all seasons. H. otakii underwent also a significant diel changes that could be related to difference of prey availability. Thus the nocturnal emergence
of gammarid amphipods, polychaetes and fishes explained their greater consumption by H. otakii. Dietary breadth of both species was lower in the smallest individuals (<5 cm SL) and in March and April 2002. This was due
to the disproportionate dry mass attributable to the consumption of amphipods by both H. otakii and H. agrammus. Dietary overlap of both species was relatively moderate to high, in particular in <9.9 cm SL (0.62 – 0.71) from May to July
2002 (0.63 – 0.71). This is coincident with higher abundances of crabs, caridean shrimps and polychaetes in the study area,
and it was assumed that these prey species were not limited resources. Higher dietary overlap was correlated with an abundance
of a shared resource and did not indicate the interspecific competition between H. otakii and H. agrammus. 相似文献
5.
Peter W. Alderks Joseph A. Sisneros 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2011,197(4):387-398
The auditory system of the plainfin midshipman fish, Porichthys notatus, is an important sensory receiver system used to encode intraspecific social communication signals in adults, but the response
properties and function of this receiver system in pre-adult stages are less known. In this study we examined the response
properties of auditory-evoked potentials from the midshipman saccule, the main organ of hearing in this species, to determine
whether the frequency response and auditory threshold of saccular hair cells to behaviorally relevant single tone stimuli
change during ontogeny. Saccular potentials were recorded from three relative sizes of midshipman fish: small juveniles [1.9–3.1 cm
standard length (SL), large juveniles (6.8–8.0 cm SL) and non-reproductive adults (9.0–22.6 cm SL)]. The auditory evoked potentials
were recorded from the rostral, middle and caudal regions of the saccule while single tone stimuli (75–1,025 Hz) were presented
via an underwater speaker. We show that the frequency response and auditory threshold of the midshipman saccule is established
early in development and retained throughout ontogeny. We also show that saccular sensitivity to frequencies greater than
385 Hz increases with age/size and that the midshipman saccule of small and large juveniles, like that of non-reproductive
adults, is best suited to detect low frequency sounds (<105 Hz) in their natural acoustic environment. 相似文献
6.
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
7.
Vieira RH Costa RA Menezes FG Silva GC Theophilo GN Rodrigues DP Maggioni R 《Current microbiology》2011,63(2):126-130
Between October 2008 and June 2009, 15 samples of 10 live oysters each (Crassostrea rhizophorae) measuring 8.31–10.71 cm were purchased from a restaurant on the seashore of Fortaleza, Brazil. The Vibrio count ranged from 75 (estimated) to 43,500 CFU/g. Fourteen species were identified among the 56 isolated Vibrio strains, with V. parahaemolyticus as the most prevalent. Two of the 17 V. parahaemolyticus strains were urease-positive and tdh- and trh-positive on multiplex PCR, but neither produced β-hemolysis halos in Wagatsuma agar. Thus, fresh oysters served in natura
in Fortaleza, Brazil, were found to contain Vibrio strains known to cause gastroenteritis in humans. 相似文献
8.
We studied habitat choice, diet, food consumption and somatic growth of Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) during the ice-covered winter period of a subarctic lake in northern Norway. Both Arctic charr and brown trout predominantly
used the littoral zone during winter time. Despite very cold winter conditions (water temperature <1°C) and poor light conditions,
both fish species fed continuously during the ice-covered period, although at a much lower rate than during the summer season.
No somatic growth could be detected during the ice-covered winter period and the condition factor of both species significantly
declined, suggesting that the winter feeding rates were similar to or below the maintenance requirements. Also, the species
richness and diversity of ingested prey largely decreased from summer to winter for both fish species. The winter diet of
Arctic charr <20 cm was dominated by benthic insect larvae, chironomids in particular, and Gammarus lacustris, but zooplankton was also important in December. G. lacustris was the dominant prey of charr >20 cm. The winter diet of brown trout <20 cm was dominated by insect larvae, whereas large-sized
trout mainly was piscivorous, feeding on juvenile Arctic charr. Piscivorous feeding behaviour of trout was in contrast rarely
seen during the summer months when their encounter with potential fish prey was rare as the small-sized charr mainly inhabited
the profundal. The study demonstrated large differences in the ecology and interactions of Arctic charr and brown trout between
the winter and summer seasons. 相似文献
9.
Prey stage preference of female Kampimodromus aberrans (Oudemans) (Phytoseiidae) at constant densities of different stages of Tetranychus urticae Koch (Tetranychidae), functional response types and parameters of the predator females to the varying densities of eggs,
larvae, protonymphs and deutonymps of T. urticae were determined in order to establish its potential for the mite biological control. Experiments were conducted at 25 ± 1°C,
65 ± 10% RH and 16:8 (L:D) photoperiod. Our results indicated that the predator consumed significantly more prey larvae than
other prey stages. Functional response type of predator was determined by a logistic regression model. The predator exhibited
a Type II response on all prey stages. The attack rate (α) and handling time (T
h
) coefficients of a Type II response were estimated by fitting a “random-predator” equation to the data. The lowest estimated
value α and the highest value of T
h
(including digestion) were obtanined for the predator feeding on deutonmph. The lowest value of T
h
were obtained for the predator feeding on prey larvae, but the attack rate value obtained on larva wasn’t different than
that obtained on egg and protonymph. According to our results, K. aberrans could be an efficient biological control agent of T. urticae at least at low prey densities. However, further field based studies are needed to draw firm conclusions. 相似文献
10.
On the family Brassicaceae, the causal agent responsible for downy mildew disease was originally regarded as a single species,
Peronospora parasitica (now under Hyaloperonospora), but it was recently reconsidered to consist of many distinct species. In this study, 11 specimens of Peronospora
drabae and P. norvegica parasitic on the genus Draba were investigated morphologically and molecularly. Pronounced differences in conidial sizes (P. drabae: 14–20 × 12.5–15.5 μm; P. norvegica: 20–29 × 15.5–22 μm) and 7.8% sequence distance between their ITS1-5.8S-ITS2 rDNA sequences confirmed their status as distinct
species. Based on ITS phylogeny and morphology (monopodially branching conidiophores, flexuous to sigmoid ultimate branchlets,
hyaline conidia and lobate haustoria), the two species unequivocally belong to the genus Hyaloperonospora and not to Peronospora to which they were previously assigned. Therefore, two new combinations, Hyaloperonospora drabae and H. norvegica, are proposed. The two taxa are illustrated and compared using the type specimen for H. norvegica and authentic specimens for H. drabae, which is lectotypified. 相似文献
11.
Johnius (Johnius) majan sp. nov. is described on the basis of 8 specimens (117–158 mm in standard length) from Oman, Indian Ocean. The new species
is distinguished from its congeners by the following combination of characters: black axillary spot on upper pectoral fin
base; dorsal soft rays 29–32; anal soft rays 8; scales above lateral line 6, below 11; eye diameter 22.9–28.9% HL; interorbital
width 32.0–38.0% HL; gill rakers 5–6 + 15–18 = 21–24; no mental barbel; last well developed pleural rib on 7th vertebra; swim
bladder appendages 11; vertebrae 10 + 14 = 24. 相似文献
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13.
Nitraria retusa and Atriplex halimus (xero-halophytes) plants were grown in the range 0–800 mM NaCl while Medicago arborea (glycophyte) in 0–300 mM NaCl. Plants were harvested after 120 days of salt-treatment. The present study was designed to
study the effect of salinity on root, stem and leaf anatomy, water relationship, and plant growth in greenhouse conditions.
Salinity induced anatomical changes in the roots, stems and leaves. The cuticle and epidermis of N. retusa and A. halimus stems were unaffected by salinity. However, root anatomical parameters (root cross section area, cortex thickness and stele
to root area ratio), and stem anatomical parameters (stem cross section area and cortex area) were promoted at 100–200 mM
NaCl. Indicating that low to moderate salinity had a stimulating effect on root and stem growth of these xero-halophytic species.
At higher salinities, root and stem structures were altered significantly, and their percentages of reduction were higher
in A. halimus than in N. retusa whereas, in M. arborea, they were strongly altered as salinity rose. NaCl (100–300 mM) reduced leaf water content by 21.2–56.2% and specific leaf
area by 51–88.1%, while increased leaf anatomical parameters in M. arborea (e.g. increased thickness of upper and lower epidermis, palisade and spongy mesophyll, entire lamina, and increased palisade
to spongy mesophyll ratio). Similar results were evidenced in A. halimus leaves with salinity exceeding 100 mM NaCl. Leaves of N. retusa were thinner in salt-stressed plants while epidermis thickness and water content was unaffected by salinity. The size of
xylem vessel was unchanged under salinity in the leaf’s main vein of the three species while we have increased number in M. arborea leaf main vein in the range of 200–300 mM NaCl. A longer distance between leaf vascular bundle, a reduced size and increased
number of xylem vessel especially in stem than in root vascular system was evidenced in M. arborea treated plants and only at (400–800 mM) in the xero-halophytic species. The effects of NaCl toxicity on leaf, stem and root
ultrastructure are discussed in relation to the degree of salt resistance of these three species. Our results suggest that
both N. retusa and A. halimus show high tolerance to salinity while M. arborea was considered as a salt tolerant species. 相似文献
14.
We investigated the size at maturation, breeding season, and morphological development of larvae and juveniles of a freshwater
pipefish Microphis leiaspis, which belongs to Gastrophori, collected from three rivers on the northern part of Okinawa-jima Island, Japan. The minimum
size of brooding males was 105–123 mm in standard length (SL). The smallest mature female was estimated to be ca. 130 mm SL
from the analysis of gonadosomatic index (GSI) and histological observations of gonads. The breeding season was estimated
to be from June to December according to monthly changes in female GSI, histological observations of gonads, and monthly changes
in the occurrence of brooding males. The number of eggs in the male brood pouch ranged from 75 to 241 (mean ± SD: 152 ± 52,
n = 22). The male releases newly hatched larvae in freshwater areas. After newborns grow in the sea, they return to freshwater
areas of the rivers and attain maturity. Microphis leiaspis was conformed to have an amphidromous life history. Notochord length of the released larvae was 6.1 mm, with a well-developed
finfold. Larvae attained 11.1 mm SL, formation of the caudal and dorsal fin rays was complete, and the caudal fin became lozenge
shaped at 30 days after the release, and juveniles reached 36.0 mm SL at 63 days after release. In the period between 30 and
63 days after the release, formation of all fins except the pectoral fins was completed, and caudal fin rays were extended
and sector shaped with deep slits between each fin ray. The morphology of the released larvae of M. leiaspis is similar to that of Gastrophori species, and the morphology of juveniles similar to other species of Microphis. 相似文献
15.
The influence of body size on the consumption of live zooplankton (Daphnia spp.) by freshwater crayfish was examined using yabbies (Cherax destructor) ranging from 5 to 45 g. Food preference between live zooplankton and inert pellets was also assessed under experimental
conditions. In experimental tanks, yabbies of four size classes (<15, 15–24.9, 25–34.9 and 35–45 g) were presented with live
Daphnia. All yabbies were held in separate tanks with five animals per size class. In yabbies less than 15 g, the feeding mode on
zooplankton involved rapid searching and probing with the first two pairs of walking legs. Once a prey was located, the chelae
on the end of these walking legs would grasp the zooplankton and then rapidly move it towards the mouthparts. Yabbies larger
than 25 g tended to use their walking legs to push the Daphnia nearer to their third maxilliped which would then force or scoop the zooplankton towards the mouthparts. A short-term feeding
trial showed that there was no significant difference between size classes in regards to zooplankton consumption (P > 0.05). Capture efficiency of live Daphnia by yabbies less than 15 g was significantly lower (76%, P = 0.008) than the three larger size classes (93.6%). Yabbies less than 15 g consumed a significantly (P < 0.001) higher percentage (5.2%) of their body weight than the other size classes (1.1%, 0.8%, and 0.6%, respectively).
In the presence of both live zooplankton and a pellet diet, yabbies spent significantly (P = 0.005) more time feeding on zooplankton (85%) than on inert pellets (15%). This was the first study to quantify zooplankton
consumption by yabbies and the results provide insights into understanding the trophic role of freshwater crayfish in structuring
zooplankton communities and the husbandry management of crayfish farming.
Handling editor: S. I. Dodson 相似文献
16.
Surface inoculation dose–response and time–response bioassays and detached fruit bioassays were conducted with a novel South
African isolate of the Cryptophlebia leucotreta granulovirus (CrleGV-SA) against Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Noctuidae) neonate larvae. LC50 and LC90 values were estimated to be 4.095 × 103 and 1.185 × 105 OBs ml−1, respectively. LT50 and LT90 values were estimated to be 4 days 22 h and 7 days 8 h, respectively, categorising the virus as a fast or type 2 granulovirus.
There was a conspicuous difference in behaviour between larvae on inoculated diet and untreated diet, resulting in a significant
reduction in penetration of diet. Bioassays on detached Navel oranges revealed LC50 and LC90 values of 9.310 × 107 and 1.515 × 109 OBs ml−1, when using data on numbers of larvae per fruit rather than on numbers of infested fruit. Field trials will be conducted. 相似文献
17.
In this work, the variability of spo0A gene in the genus Geobacillus and applicability of this gene for the taxonomy within this genus were evaluated. The protein Spo0A is the master regulator
of the endospore-forming process in the all endospore-forming bacteria. Geobacillus genus-specific primers GEOSPO were designed based on the sequences of Geobacillus
spo0A gene available through the public databases. Inter and intraspecific variability of Geobacillus spo0A gene was determined after sequencing of the GEOSPO-PCR products. Geobacillus
spo0A sequence analysis showed that three species—Geobacillus thermodenitrificans, G. stearothermophilus, and G. jurassicus—could be easily identified. Similarity between the sequences of these species and the other species were in the range of 83.3%–92.0%.
In contrast, intraspecific similarity of G. thermodenitrificans and G. stearothermophilus was high—above 99.0%. Similarity of spo0A sequences of G. subterraneus–G. uzenensis species cluster also matched this interval. Intercluster similarity between G. lituanicus–G. thermoleovorans–G. kaustophilus–G. vulcani and G. thermocatenulatus–G. gargensis–G. caldoxylosilyticus–G. toebii–G. thermoglucosidasius species clusters, as well as interspecific similarity within these two clusters was in the range of the intraspecific similarity
determined for G. thermodenitrificans and G. stearothermophilus. It was also determined that spo0A cannot be used as the phylogenetic marker for the genus Geobacillus. 相似文献
18.
The tortoise tick Hyalomma aegyptium has a typical three-host life-cycle. Whereas its larvae and nymphs are less host-specific feeding on a variety of tetrapods,
tortoises of the genus Testudo are principal hosts of adults. Ticks retained this trait also in our study under laboratory conditions, while adults were
reluctant to feed on mammalian hosts. Combination of feeding larvae and nymphs on guinea pigs and feeding of adults on Testudo marginata tortoises provided the best results. Feeding period of females was on average 25 days (range 17–44), whereas males remain
after female engorgement on tortoise host. Female pre-oviposition period was 14 days (3–31), followed by 24 days of oviposition
(18–29). Pre-eclosion and eclosion, both together, takes 31 days (21–43). Larvae fed 5 days (3–9), then molted to nymphs after
17 days (12–23). Feeding period of nymphs lasted 7 days (5–10), engorged nymphs molted to adults after 24 days (19–26). Sex
ratio of laboratory hatched H. aegyptium was nearly equal (1:1.09). The average weight of engorged female was 0.95 (0.72–1.12) g. The average number of laid eggs
was 6,900 (6,524–7,532) per female, it was significantly correlated with weight of engorged female. Only 2.8% of engorged
larvae and 1.8% of engorged nymphs remained un-molted and died. Despite the use of natural host species, feeding success of
females reached only 45%. The whole life-cycle was completed within 147 days (98–215). 相似文献
19.
Knowledge of how energetic parameters relate to fluctuating factors in the natural habitat is necessary when evaluating the
role of gelatinous zooplankton in the carbon flow of coastal waters. In laboratory experiments, we assessed feeding, respiration
and growth of the ctenophore, Pleurobrachia pileus, and constructed carbon budgets. Clearance rates (F, l d−1) of laboratory-reared Acartia tonsa as prey increased as a function of ctenophore polar length (L, mm) as F = 0.17L
1.9. For ctenophores larger than about 11 mm, clearance rate was depressed in containers of 30–50 l volume. Clearance rates on
field-collected prey were highest on the copepod, Centropages typicus, intermediate on the cladoceran, Evadne
nordmanni and low on the copepods, Acartia clausi and Temora longicornis. Specific growth rates of 8–10 mm P. pileus increased with increasing prey concentrations to a maximum of 0.09 d−1 attained at prey carbon densities of 40 and 100 μg C l−1 of Artemia salina and A. tonsa, respectively. Weight-specific respiration rates increased hyperbolically with prey concentration. From experiments in which
growth, ingestion and respiration were measured simultaneously, a carbon budget was constructed for individuals growing at
maximum rates; from the measured parameters, the assimilation efficiency and net growth efficiency were estimated to be 22
and 37%, respectively. We conclude that the predation rates of P. pileus depend on ctenophore size, prey species, prey density and experimental container volume. Because the specific growth rates,
respiration, assimilation and net growth efficiencies all were affected by food availability, knowledge of the ambient prey
field is critical when evaluating the role of P.
pileus in the carbon flow in coastal waters. 相似文献
20.