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1.
Potamotrygon marquesi, sp. nov., is described and compared with other species of Potamotrygon occurring in the Amazon Basin. The identity of this new species is supported by an extensive external and internal morphological study including coloration pattern, squamation, skeleton and ventral lateral-line canals. Morphometrics and meristics were used to further distinguish P. marquesi from congeners. Potamotrygon marquesi was first considered to fall within the range of variation found in P. motoro. However, even with an extensive variation in coloration observed in P. motoro, this new species presents a series of autapomorphies that confidently distinguishes it from what is understood as the morphological variation found in P. motoro. Additional morphological characters that diagnose P. marquesi include three angular cartilages, asymmetrical star-shaped denticles, a single regular row of spines on tail dorsum, lateral row of caudal spines near the sting insertion, dorsal disc background in beige and grey mixed with shades of grey and bearing open and closed bicolored rings, among others. Although presenting a gap of distribution along the west–east extension of the Amazon Basin, its diagnostic charactistics are consistent in both recorded regions. Our study supports the need for many morphological characters to robustly distinguish members of Potamotrygoninae considering their extremely variable dorsal disc color pattern.  相似文献   

2.
The new species of digger wasps, Belomicroides rufus, is described from North Africa. The new species differs from the all members of the Belomicroides schmiedeknechtii species-group in the pale coloration and dense pubescence of the body.  相似文献   

3.
Jang-Liaw NH  Gong YH  Chen IS 《ZooKeys》2012,(199):13-21
A new species of Clariger Jordan & Snyder, 1901 was collected from northern Taiwan. The genus was previously known only from Japanese waters. This discovery is the first formal and southernmost record of these marine gobies from the waters of subtropical Taiwan. The new species, Clariger taiwanensissp. n., is distinguished from its congeners by a unique combination of features: (1) fin rays: dorsal-fin rays III, I/8; anal-fin rays modally I/8; and pectoral-fin rays modally 19 (2+16+1); (2) longitudinal dermal ridge on head with 6 barbels; and (3) specific coloration pattern: head and trunk dark brown with scattered pale spots and blotches; cheek, ventral portion of head sometimes pale with deep brown spots; pectoral-fin base with a dark brown band; and caudal fin mostly dark brown proximally and with alternating and irregular dark brown and pale bands distally. A diagnostic key to all nominal species from Japan and Taiwan is provided.  相似文献   

4.
The only known monocotylid genus to parasitise Neotropical freshwater stingrays (Potamotrygonidae) is Potamotrygonocotyle Mayes, Brooks & Thorson, 1981, a monotypic genus erected to accommodate P. tsalickisi Mayes, Brooks & Thorson, 1981. For more than 20 years, no other species has been recognised in this genus, but new efforts to survey the diversity of parasites inhabiting potamotrygonids have revealed the existence of new species and the need to redefine the genus. Here, the generic diagnosis of Potamotrygonocotyle is amended, P. tsalickisi is redescribed and four new species are recognised and described based on samples collected from the gills of freshwater potamotrygonids from the La Plata river basin: Potamotrygonocotyle chisholmae n. sp. and P. dromedarius n. sp. from Potamotrygon motoro; Potamotrygonocotyle eurypotamoxenus n. sp. from Potamotrygon cf. motoro (type-host), P. castexi, P. falkneri and P. histrix; and Potamotrygonocotyle uruguayensis n. sp. from Potamotrygon brachyura. Potamotrygonocotyle is characterised by species possessing: (1) slightly sinuous sclerotised ridges on all septa; (2) two pairs of the dorsal haptoral accessory structures associated with the four posterior peripheral loculi and with anterior dorsal haptoral accessory structure bilobate or semicircular; and (3) male copulatory organ without an accessory piece.  相似文献   

5.
Climate change acts as a major new selective agent on many organisms, particularly at high latitudes where climate change is more pronounced than at lower latitudes. Studies are required to predict which species are at a high risk of extinction and whether certain phenotypes may be more affected by climate change than others. The identification of susceptible phenotypes is important for evaluating the potential negative effect of climate change on biodiversity at the inter‐ and intraspecific levels. Melanin‐based coloration is an interesting and easily accessible candidate trait because, within certain species, reddish pheomelanin‐based coloration is associated with adaptations to warm climates. However, it is unclear whether the same holds among species. We tested one prediction of this hypothesis in four owl genera (wood, scops, screech, and pygmy owls), namely that darker reddish species are more prevalent near the equator than polewards. Our comparative analysis is consistent with this prediction for the northern hemisphere, suggesting that pale reddish species may be adapted to cold climates and dark reddish species to warmer climates. Thus, climate change may have a larger negative impact on pale pheomelanic owls and favour dark pheomelanic species. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 573–582.  相似文献   

6.
Predation risk is allegedly reduced in Batesian and Müllerian mimics, because their coloration resembles the conspicuous coloration of unpalatable prey. The efficacy of mimicry is thought to be affected by variation in the unpalatability of prey, the conspicuousness of the signals, and the visual system of predators that see them. Many frog species exhibit small colorful patches contrasting against an otherwise dark body. By measuring toxicity and color reflectance in a geographically variable frog species and the syntopic toxic species, we tested whether unpalatability was correlated with between‐species color resemblance and whether resemblance was highest for the most conspicuous components of coloration pattern. Heterospecific resemblance in colorful patches was highest between species at the same locality, but unrelated to concomitant variation in toxicity. Surprisingly, resemblance was lower for the conspicuous femoral patches compared to the inconspicuous dorsum. By building visual models, we further tested whether resemblance was affected by the visual system of model predators. As predicted, mimic‐model resemblance was higher under the visual system of simulated predators compared to no visual system at all. Our results indicate that femoral patches are aposematic signals and support a role of mimicry in driving phenotypic divergence or mimetic radiation between localities.  相似文献   

7.
There are two major forms of protective coloration, camouflage and warning coloration, which often entail different colour pattern characteristics. Some species change strategy between or within life stages and one such example is the striated shieldbug, Graphosoma lineatum. The larvae and the pale brownish-and-black striated pre-diapause adults are more cryptic in the late summer environment than is the red-and black striation that the adults change to after diapause in spring. Here we investigate if the more cryptic pre-diapause adult and larval coloration may affect the aposematic function of the coloration as compared to the red adult form. In a series of trials we presented fifth instar larvae, pale or red adults to shieldbug-naïve domestic chicks, Gallus gallus domesticus, to investigate the birds’ initial wariness, avoidance learning, and generalization between the three prey types. The naïve chicks found the red adults most aversive followed by pale adults, and they found the larvae the least aversive. The birds did not find the larvae unpalatable and did not learn to avoid them, while they learned to avoid the two adult forms and then to a similar degree. Birds generalized asymmetrically between life stages, positively from larvae to adults and negatively from adults to larvae. We conclude that the lower conspicuousness in the pale forms of G. lineatum may entail a reduced aposematic function, namely a reduced initial wariness in inexperienced birds. The maintenance of the colour polymorphism is discussed.  相似文献   

8.
The sex steroid testosterone has been shown to regulate the development of male-specific coloration in many organisms that exhibit sexual dichromatism, but the role of testosterone is less certain for species in which both sexes express bright coloration. Lizards in the genus Sceloporus possess bright blue patches on their throats and abdomens. These patches, which are used in social signaling, are often regulated by testosterone and are consequently expressed only in males of most species. However, Yarrow's Spiny Lizard (Sceloporus jarrovii, Cope 1875) exhibits a derived condition in which both sexes express bright blue ventral patches despite dramatic sexual differences in circulating testosterone levels throughout postnatal ontogeny. In this study, we used surgical castration and hormone replacement in juvenile males to test the hypothesis that testosterone stimulates the expression of blue ventral coloration in S. jarrovii. In two separate experiments conducted in captivity and the natural field environment, we found that surgical castration decreased the hue and saturation while increasing the brightness of blue throat and abdominal patches. Castration also decreased the amount of black pigment bordering the blue throat patch. Treatment of castrated males with exogenous testosterone restored all aspects of ventral coloration to values similar to those of intact control males. Early organizational effects of testosterone during prenatal development may lead to the expression of blue coloration in both sexes, but the results of our present experiments indicate that subsequent effects of testosterone during sexual maturation further enhance the coloration of males.  相似文献   

9.
Two new species of the pyralid genus Pyrausta Schrank, 1802, P. anastasia Shodotova, sp. n. from southern Siberia and P. alexandra Shodotova, sp. n. from the Transcaucasia, are described. P. anastasia sp. n. is very similar to P. chrysitis (Butler, 1881) in coloration and the wing pattern, but differs in the darker brown fore wings, a wider pale yellow band on the hind wing, and the structure of the aedeagus. P. alexandra sp. n. is very similar to P. falcatalis (Guenée, 1854) in coloration and the wing pattern, but differs in the darker brown wings, in the number of pale yellow spots on the fore and hind wings, and in the structure of the male and female genitalia. The holotypes and paratypes of both species are deposited in the Zoological Institute, Russian Academy of Sciences (St. Petersburg).  相似文献   

10.
Trixagus baluchicus sp. n. from southeastern Iran is described. The new species is similar to T. duvalii (Bonvouloir, 1859), but differs from the latter in the narrower body more strongly tapered posteriorly, pale rustybrown coloration, less transverse pronotum, sparser punctation, distinct punctures on the elytral interstriae, somewhat narrower antennal club, wider parameres evenly convex at sides, and more elongate phallobase enlarged only in the basal third.  相似文献   

11.
 Two new species of chimaeroid fishes from the family Chimaeridae are described on the basis of morphological characters. The carpenter's chimaera is a large-bodied species of Chimaera distinguished from its congeners by massive head with blunt snout; firm, nondeciduous skin; purplish color; preopercular and oral lateral line canals branching together; and pelvic claspers that are divided for the distal one third of length, purple at the base with white fleshy tips. The pale ghost shark is a species of Hydrolagus distinguished from its congeners by a dorsal fin spine that reaches to the origin of the second dorsal fin when depressed; elongate second dorsal fin not indented along its length; preopercular and oral lateral line canals sharing a common branch; long, stout caudal filament; and pale silvery-gray coloration fading to white ventrally. The pale ghost shark has long been recognized as a new species from New Zealand, and formal taxonomic recognition of this species will prove important for fishery management. Received: October 15, 2001 / Revised: May 1, 2002 / Accepted: May 29, 2002 Acknowledgments I am grateful to Peter Last, Alastair Graham (CSIRO, Dept. of Marine Research), Clive Roberts, Andrew Stewart (NMNZ, Wellington), and Mark McGrouther and Doug Hoese (AMS, Sydney), for their hospitality and support of this research. This work was funded by grants from the National Science Foundation (NSF DEB-9510735) and the National Geographic Society (no. 5414–95), and also funded in part by the New Zealand Foundation for Scientific Research and Technology, Biosystematics of NZ EEZ Fishes Project, contract MNZ603, C. Roberts, program leader.  相似文献   

12.
Male animals of many species use conspicuous coloration to attract mates. Among mammals, primates possess the most brilliant secondary sexual coloration. However, whether colour plays a part in primate female mate choice remains unknown. Adult male rhesus macaques undergo a hormonally regulated increased reddening of facial and anogenital skin during their mating season. We experimentally investigated whether red male facial coloration is preferred by simultaneously presenting female rhesus macaques (n = 6) with computer-manipulated pale and red versions of 24 different male faces. The duration and direction of gaze were measured to discern visual preferences. Females exhibited preferences for the red versions of male faces. It is proposed that male coloration might provide a cue to male quality.  相似文献   

13.
Morphological features of the species of the genus Adoxomyia Kertész, 1907 with bicolorous antennae in females were studied for the first time. Significant diagnostic characters are discussed, e.g., the structure of the head, the type of pubescence on the frons and face, the shape and coloration of the scutellar spines, and the morphology of the genitalia (the synstemum, the basal part of the epandrium, and the aedeagus). A new species, Adoxomyia subruficornis sp. n., is described from Uzbekistan and Tajikistan; it differs from A. ruficornis (Loew, 1873) in a dense pale pubescence on the frons, pale scutellar spines, elongate median projection of the synstemum, and rounded epandrial processes.  相似文献   

14.
1. Protective coloration in insects may be aposematic or cryptic, and some species change defensive strategy between instars. In Sweden, the adult striated shieldbugs Graphosoma lineatum (Heteroptera: Pentatomidae) undergo a seasonal colour change from pale brown and black striation in the pre‐hibernating adults, to red and black striation in the same post‐hibernating individuals. To the human eye the pre‐hibernating adults appear cryptic against the withered late summer vegetation, whereas the red and black post‐hibernating adults appear aposematic. This suggests a possibility of a functional colour change. However, what is cryptic to the human eye is not necessarily cryptic to a potential predator. 2. Therefore we tested the effect of coloration in adult G. lineatum on their detectability for avian predators. Great tits (Parus major) were trained to eat sunflower seeds hidden inside the emptied exoskeletons of pale or red G. lineatum. Then the detection time for both colour forms was measured in a dry vegetation environment. 3. The birds required a longer time to find the pale form of G. lineatum than the red one. The pale form appears more cryptic on withered late summer vegetation than the red form, not only to the human eye but also to avian predators. The result supports the idea that the adult individuals of G. lineatum undergo a functional change from a cryptic protective coloration to an aposematic one.  相似文献   

15.
A new species ofChimaera is described from three specimens collected from deep water fishing grounds off the North Island of New Zealand at depths ranging from 327–1020 m. This species is distinguished from all other members of the genus by gray coloration with chocolate brown reticulations and spots covering the body and fins, as well as additional external features such as rounded pelvic fins, first dorsal fin with distinct white margin, preopercular and oral lateral line canals sharing a common branch, and morphology of pelvic claspers in males bifid, the distal 1/3 divided, with pale colored fleshy, distal lobes. Comparisons are made toC. monstrosa andC. owstoni, the two most similar species in the genus. this represents the first species ofChimaera to be described from New Zealand.  相似文献   

16.
The remarkable diversity of coloration and species present in hummingbirds has been considered the result of sexual selection. I evaluate if color differences among species in the genus Coeligena are consistent with expectations from sexual selection theory. If sexual selection on color is important for speciation, closely related species should be markedly different in the colors of feather patches associated with aggression and breeding. I evaluate this prediction through a statistical assessment of the phylogenetic signal of colors from five feather patches: crown, gorget, belly, upper back, and rump. The first two are associated with aggressive and courtship displays and are expected to be under sexual selection, whereas the others are not. Contrary to expectations, the crown and gorget were the only patches with significant phylogenetic signal. Furthermore, I assess if populations of dichromatic species are more divergent in coloration and therefore have reduced gene flow. Color distances among dichromatic subspecies were larger than among monochromatic subspecies, but the magnitude of phenotypic differentiation was not related to levels of gene flow. These results support a role for sexual selection in shaping color variation among populations, but these differences alone are not sufficient to explain speciation.  相似文献   

17.
1. The theory on adaptive phenotypic plasticity assumes different fitness optima in different environments. To demonstrate these fitness differences in the field or under laboratory conditions can be difficult.
2. The size of the coloured patches on the abdomen of Eristalis arbustorum varies with rearing temperature. At low temperatures small patches develop and at higher temperatures larger patches develop. Consequently, the colour patch size varies seasonally.
3. To study the relative fitness of two extreme phenotypes in abdominal coloration in the summer, a total of 591 laboratory-reared flies were released in six large population cages. As a measure of fitness, survival was estimated.
4. In all replicate cages the survival of the pale phenotypes was higher than that of the dark phenotypes, indicating a higher fitness for the pale flies under summer conditions.
5. The fat content of flies reared under identical conditions to those released in the cages was measured. Pale flies had ≈ 0·7 mg more fat than dark flies (± 25% extra fat). However, it is argued that this difference in fat reserves could not have been the only cause of the observed difference in survival.
6. The results are discussed in relation to mimicry and thermoregulation.  相似文献   

18.
记述了盲蝽科1新种,金毛束盲蝽Pilophorus fulvicomus sp.nov.。报道了中国4新纪录种:印度蚁叶盲蝽Hallodapus indicus(Poppius,1911),九州蚁叶盲蝽Hallodapus kyushuensis M iyamoto,1966,贝克束盲蝽Pilophorus bakeriSchuh,1984和印支宽敖盲蝽Wygomiris indochinensis(Schuh,1984)。提供了新种和新纪录种雄性生殖器特征图。模式标本保存于南开大学昆虫学研究所。  相似文献   

19.
李海蛟  何双辉 《菌物学报》2014,33(5):967-975
报道了多孔菌3个中国新记录种,其中包括1个新组合种:胭脂红栓孔菌。褐白革孔菌Coriolopsis brunneoleuca采自广西、海南和云南省,该种的主要特征为子实体盖形,菌盖表面浅黄褐色至黄褐色,被绒毛,骨架菌丝和缠绕菌丝有拟糊精反应;婆罗洲榆孔菌Elmerina borneensis采自福建和海南省,子实体平伏,子实层中较多大的菌丝钉,担子纵分隔;胭脂红栓孔菌Trametes coccinea采自吉林省,子实体橘黄色、浅红褐色、红色至砖红色,孔口小。文中对这3个种进行了详细的描述和显微结构绘图并且提供了红色栓孔菌种类(即红孔菌属种类)的检索表。  相似文献   

20.
The interplay between colour vision and animal signalling is of keen interest to behavioural ecologists and evolutionary biologists alike, but is difficult to address in terrestrial animals. Unlike most avian lineages, in which colour vision is relatively invariant among species, the fairy‐wrens and allies (Maluridae) show a recent gain of ultraviolet sensitivity (UVS). Here, we compare the rates of colour evolution on 11 patches for males and females across Maluridae in the context of their visual system. We measured reflectance spectra for 24 species, estimating five vision‐independent colour metrics as well as metrics of colour contrast among patches and sexual dichromatism in a receiver‐neutral colour space. We fit Brownian motion (BM) and Ornstein–Uhlenbeck (OU) models to estimate evolutionary rates for these metrics and to test whether male coloration, female coloration or dichromatism was driven by selective regimes defined by visual system or geography. We found that in general male coloration evolved rapidly in comparison with females. Male colour contrast was strongly correlated with visual system and expanded greatly in UVS lineages, whereas female coloration was weakly associated with geography (Australia vs. Papua New Guinea). These results suggest that dichromatism has evolved in Maluridae as males and females evolve at different rates, and are driven by different selection pressures.  相似文献   

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