首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Diurnal birds belong to one of two classes of colour vision. These are distinguished by the maximum absorbance wavelengths of the SWS1 visual pigment sensitive to violet (VS) and ultraviolet (UVS). Shifts between the classes have been rare events during avian evolution. Gulls (Laridae) are the only shorebirds (Charadriiformes) previously reported to have the UVS type of opsin, but too few species have been sampled to infer that gulls are unique among shorebirds or that Laridae is monomorphic for this trait. We have sequenced the SWS1 opsin gene in a broader sample of species. We confirm that cysteine in the key amino acid position 90, characteristic of the UVS class, has been conserved throughout gull evolution but also that the terns Anous minutus, A. tenuirostris and Gygis alba, and the skimmer Rynchops niger carry this trait. Terns, excluding Anous and Gygis, share the VS conferring serine in position 90 with other shorebirds but it is translated from a codon more similar to that found in UVS shorebirds. The most parsimonious interpretation of these findings, based on a molecular gene tree, is a single VS to UVS shift and a subsequent reversal in one lineage.  相似文献   

2.
Natural selection is considered a major force shaping brain size evolution in vertebrates, whereas the influence of sexual selection remains controversial. On one hand, sexual selection could promote brain enlargement by enhancing cognitive skills needed to compete for mates. On the other hand, sexual selection could favour brain size reduction due to trade‐offs between investing in brain tissue and in sexually selected traits. These opposed predictions are mirrored in contradictory relationships between sexual selection proxies and brain size relative to body size. Here, we report a phylogenetic comparative analysis that highlights potential flaws in interpreting relative brain size‐mating system associations as effects of sexual selection on brain size in shorebirds (Charadriiformes), a taxonomic group with an outstanding diversity in breeding systems. Considering many ecological effects, relative brain size was not significantly correlated with testis size. In polyandrous species, however, relative brain sizes of males and females were smaller than in monogamous species, and females had smaller brain size than males. Although these findings are consistent with sexual selection reducing brain size, they could also be due to females deserting parental care, which is a common feature of polyandrous species. Furthermore, our analyses suggested that body size evolved faster than brain size, and thus the evolution of body size may be confounding the effect of the mating system on relative brain size. The brain size‐mating system association in shorebirds is thus not only due to sexual selection on brain size but rather, to body size evolution and other multiple simultaneous effects.  相似文献   

3.
As field determinations take much effort, it would be useful to be able to predict easily the coefficients describing the functional response of free-living predators, the function relating food intake rate to the abundance of food organisms in the environment. As a means easily to parameterise an individual-based model of shorebird Charadriiformes populations, we attempted this for shorebirds eating macro-invertebrates. Intake rate is measured as the ash-free dry mass (AFDM) per second of active foraging; i.e. excluding time spent on digestive pauses and other activities, such as preening. The present and previous studies show that the general shape of the functional response in shorebirds eating approximately the same size of prey across the full range of prey density is a decelerating rise to a plateau, thus approximating the Holling type II ('disc equation') formulation. But field studies confirmed that the asymptote was not set by handling time, as assumed by the disc equation, because only about half the foraging time was spent in successfully or unsuccessfully attacking and handling prey, the rest being devoted to searching.A review of 30 functional responses showed that intake rate in free-living shorebirds varied independently of prey density over a wide range, with the asymptote being reached at very low prey densities (<150/m-2). Accordingly, most of the many studies of shorebird intake rate have probably been conducted at or near the asymptote of the functional response, suggesting that equations that predict intake rate should also predict the asymptote.A multivariate analysis of 468 'spot' estimates of intake rates from 26 shorebirds identified ten variables, representing prey and shorebird characteristics, that accounted for 81% of the variance in logarithm-transformed intake rate. But four-variables accounted for almost as much (77.3%), these being bird size, prey size, whether the bird was an oystercatcher Haematopus ostralegus eating mussels Mytilus edulis, or breeding. The four variable equation under-predicted, on average, the observed 30 estimates of the asymptote by 11.6%, but this discrepancy was reduced to 0.2% when two suspect estimates from one early study in the 1960s were removed. The equation therefore predicted the observed asymptote very successfully in 93% of cases. We conclude that the asymptote can be reliably predicted from just four easily measured variables. Indeed, if the birds are not breeding and are not oystercatchers eating mussels, reliable predictions can be obtained using just two variables, bird and prey sizes. A multivariate analysis of 23 estimates of the half-asymptote constant suggested they were smaller when prey were small but greater when the birds were large, especially in oystercatchers. The resulting equation could be used to predict the half-asymptote constant, but its predictive power has yet to be tested. As well as predicting the asymptote of the functional response, the equations will enable research workers engaged in many areas of shorebird ecology and behaviour to estimate intake rate without the need for conventional time-consuming field studies, including species for which it has not yet proved possible to measure intake rate in the field.  相似文献   

4.
5.

Background  

Phylogenetic hypotheses of higher-level relationships in the order Charadriiformes based on morphological data, partly disagree with those based on DNA-DNA hybridisation data. So far, these relationships have not been tested by analysis of DNA sequence data. Herein we utilize 1692 bp of aligned, nuclear DNA sequences obtained from 23 charadriiform species, representing 15 families. We also test earlier suggestions that bustards and sandgrouses may be nested with the charadriiforms. The data is analysed with methods based on the parsimony and maximum-likelihood criteria.  相似文献   

6.
7.
8.
Falcaustra odaiensis n. sp. (Nematoda: Cosmocercoidea: Kathlaniidae) is described from the Japanese clawed salamander, Onychodactylus japonicus (Houttuyn, 1782), and Ishizuchi salamander, Hynobius hirosei Lantz, 1931 (Caudata: Hynobiidae), in Japan. This nematode is characterized by having multiple pseudosuckers in the male. It resembles Falcaustra araxiana, Falcaustra duyagi, Falcaustra lambdiensis, Falcaustra pillaii, Falcaustra siamensis, and Falcaustra washingtonensis, but is readily distinguished by the spicule length and/or egg size. This is the first Falcaustra species described from Japanese salamanders.  相似文献   

9.
During an investigation of the diversity of metazoan parasites of 7 freshwater fish species from 3 localities in central Panama, the following gill dactylogyrid (Monogenoidea) species were found: Aphanoblastella chagresii n. sp. from Pimelodella chagresi (Heptapteridae); Aphanoblastella travassosi (Price, 1938) Kritsky, Mendoza-Franco, and Scholz, 2000 from Rhamdia quelen (Heptapteridae); Diaphorocleidus petrosusi n. sp. from Brycon petrosus (Characidae); Gussevia asota Kritsky, Thatcher, and Boeger, 1989, from Astronotus ocellatus (Cichlidae); Sciadicleithrum panamensis n. sp. from Aequidens coeruleopunctatus (Cichlidae); Urocleidoides flegomai n. sp. from Piabucina panamensis (Lebiasinidae); and Urocleidoides similuncus n. sp. from Poecilia gillii (Poeciliidae). Consideration of the comparative morphology and distribution of these parasites along with the evolutionary history of the host fishes suggests that diversification may be associated with geotectonic events that provided isolation of the Central American fauna with the uplift of the Panamanian Isthmus during early Pliocene (3 mya).  相似文献   

10.
Thirteen species of helminth parasites were recovered from six species of charadriid shorebirds (Aves: Charadriiformes) from Belize: the ruddy turnstone, Arenaria interpres, the snowy plover, Charadrius alexandrinus, the semipalmated plover, C. semipalmatus, the killdeer, C. vociferus, the white-rumped sandpiper, Calidris fuscicollis, and the black-bellied plover, Pluvialis squatarola. Cestode species were predominant (N = 8), followed by trematode species (N = 3) and acanthocephala (N = 2). The trematode, Paramaritremopsis solielangi infected four of the six species of hosts. The cestodes, Nadejdolepis litoralis and N. paranitidulans infected three and two host species respectively. Helminth parasite species were contagious (clumped) and not evenly distributed among hosts. Twelve of the 13 species were generalists. The one specialist Microphallus kinsellae was recovered from one C. fuscicollis. Three of the four types of feeding guilds were present and in approximately the same number. All but M. kinsellae have been reported from other species of hosts, mostly from Eurasia and North America.  相似文献   

11.
12.
13.
Abstract

Seven new species of nematode are described from the hind-gut of several different millipedes indigenous to New Zealand: Heth hamatus n. sp. from Spirobollelus antipodarus and Icosidemus hochstetteri from Auckland, Erythrodemus echinopogon from Seddonville, and Eumasligonus sp. from Aickens, and Avenue Scenic Reserve; Thelastoma moko n. sp. from coastal specimens of Eumastigonus sp.; Thelastoma rigo n. sp. from montane specimens of Eumastigonus sp.; Dudekemia prolifica n. sp. from Spirobellelus antipodarus; Dudekemia alpinensis n. sp. from the montane Eumastigonus sp.; Dudekemia kaorinus n. sp. from Eumastigonus kaorinus from Hardys Creek; and Dudekemia hirsutus n. sp. from Erythrodemus echinopogon from Seddonville.

The family Rhigonematidae is reviewed.  相似文献   

14.
Viktorocara torea and Sciadiocara tarapunga n. spp. are described from specimens from the gizzards of Haematopus ostralegus finschi and Larus novaehollandiae scopulinus respectively. All hosts were collected in the South Island, New Zealand. V. torea is characterised by the possession of doubly bifid apices to the long spicule and absence of a subterminal spicular spur; presence of six preanal papillae, the first and second widely spaced: the muscular region of the oesophagus constituting about one quarter of the total length of the oesophagus. S. tarapunga is similar to S. umbellifera, but differs in having the muscular region of the oesophagus shorter than the glandular region, a more slender body in both sexes, much smaller spicules (78--91 micrometer and 275--359 micrometer) with the right spicule not more than one-third as long as the left one. The long spicule bears a pair of similar, rounded, laterally placed spatulate apices. It is suggested that Sciadiocara umbellifera of previous authors may encompass more than one species.  相似文献   

15.
Six new species of the coral genus Acropora arc described from Indonesia. These include a species which is remarkable for tubercular cocnostcal structures similar to those of the confamilial genus Montipora. The new species include three regional endemics (A. togianensis and A. batunai from central east Sulawesi and A. derawanensis from east Kalimantan), one species with broad distribution across the southern island chains (A. sukarnoi) and two species which occur throughout most of the Indonesian archipelago (A. Indonesia and A. hoeksemai). A further two species described from Western Australia and Papua New Guinea in 1994 (A. turaki and A. jacquelineae respectively) are recorded from Indonesia for the first time, as common members of an unusual assemblage type in the Togian Islands. The range of another species described from Lombok in 1994 (A. suharsonoi) is extended into Bali. With A. desalwii, A. lokani and A. indiana , this brings to 12 the number of Acropora species newly recorded as being endemic to the Indonesian archipelago or to Indonesia and one adjoining region (either the Indian Ocean or the western Pacific).  相似文献   

16.
17.
ABSTRACT Despite the critical role of fat in providing energy for large‐scale seasonal movements, little is known about the fatty acid composition of shorebird depot fat. Fatty acid composition is important because it may impact flight performance and seasonal migratory movements. We analyzed the fatty acid composition of depot fat of 12 species of shorebirds collected during spring migration at stopover sites in Kansas from two different subcutaneous fat depots (furcular and saddle depots). Five fatty acids (palmitate [16:0], palmitoleate [16:1], stearate [18:0], oleate [18:1n‐9], and vaccenate [18:1n‐7]) accounted for 70–96% of the total composition of depot fat despite the diverse foraging behaviors of the species sampled. This similarity in fatty acid profiles may be due to a limited availability of high‐lipid food items in the shallow water and mudflat habitats where migratory shorebirds forage in the southern Great Plains. In addition, shorebird depot fat was composed primarily of long‐chain saturated and monounsaturated fatty acids (i.e., 16‐ and 18‐carbon), fatty acids thought to be more easily converted to energy during migration. Depot fat in the furcular depot was similar in composition to fat from the saddle depot, and we found no differences in fatty acid composition of the adipose tissue of males and females. Thus, our results suggest that representative shorebird depot fat fatty acid profiles can be obtained even if investigators are limited to sampling one sex, and that adipose tissue collected from saddle depots provide representative samples so biopsies can be limited to areas of the body with the least impact on flight performance.  相似文献   

18.
Fischthal and Nasir (1974) reported Neohaematotrephus brasilianum (as Cyclocoelum brasilianum) in the spotted-sandpiper Actitis macularia from Venezuela. Three voucher specimens from that report, deposited in the United States National Parasite Collection, however, differ from N. brasilianum by having the cirrus sac on the sinistral side of the body, which resembles N. facioi, N. arayae, and N. gendrei. The new species is similar to N. brasilianum by having vitelline follicles extending well anterior to the intestinal bifurcation and by having a short and laterally displaced cirrus sac whose posterior end does not reach the intestinal bifurcation, whereas all other members of Neohaematotrephus have a cirrus sac that is medially oriented. Neohaematotrephus gendrei and N. facioi have cirrus sacs that extend to the level of the intestinal bifurcation, and N. arayae has a cirrus sac that extends well posterior to the posterior margin of the ceca. By having the ovary on the sinistral side of the body, the new species is similar to N. brasilianum, N. gendrei, and N. arayae but differs from N. facioi, in which the ovary is dextral.  相似文献   

19.
Many desmid taxa were found in collections from Asia (Japan, Cambodia, Malaysia and Thailand). The following 21 new taxa and two new combinations belonging to five genera (Closterium, Euastrum, Cosmarium, Xanthidium and Staurastrum) and a rare species of Xanthidium, are reported. These include Closterium nasutum Nordstedt var. kazukoae Kanetsuna var. nov., Closterium nematodes Joshua var. nematodes f. kriegeri Kanetsuna f. nov., Euastrum binale (Turpin) Ehrenberg ex Ralfs var. protuberans Kanetsuna var. nov., Euastrum borgeanum Scott et Prescott var. cambodiense Kanetsuna var. nov., Euastrum dubium Nägeli var. protuberans Kanetsuna var. nov., Euastrum fissum W. et G. S. West var. yasukoae Kanetsuna var. nov., Euastrum gemmatum Brébisson var. tenuius Krieger f. porosum (Förster) Kanetsuna comb. nov., Euastrum pseudojenneri Scott et Prescott var. glabrum Kanetsuna var. nov., Cosmarium denticulatum Borge var. multispinum (Hirano) Kanetsuna comb. nov., Cosmarium furcatospermum W. et G. S. West var. fallax Kanetsuna var. nov., Cosmarium pileatum Borge var. cambodiense Kanetsuna var. nov., Cosmarium retusiforme (Wille) Gutwinski var. incrassatum Gutwinski f. retusum Kanetsuna f. nov., Cosmarium trapezoideum Kanetsuna sp. nov., Cosmarium zonatum Lundell var. zonatum f. majus Kanetsuna f. nov., Xanthidium cristatum Brébisson var. delpontei Roy et Bisset f. mizoroensis Kanetsuna f. nov., Xanthidium fasciculatum Ehrenberg ex Ralfs var. siamense Kanetsuna var. nov., Xanthidium pseudofreemanii Kanetsuna sp. nov., Xanthidium subtrilobum W. et G. S. West var. inornatum Skuja f. depressum Kanetsuna f. nov., Xanthidium subtrilobum W. et G. S. West var. inornatum Skuja f. singulare Kanetsuna f. nov., Staurastrum boergesenii Raciborski var. verrucosum Kanetsuna var. nov., Staurastrum dickiei Ralfs var. polypyrenoideum Kanetsuna var. nov., Staurastrum neglectum G. S. West var. fuseense Kanetsuna var. nov., Staurastrum trissacanthum Scott et Prescott var. dissacanthum Scott et Prescott f. longispinum Kanetsuna f. nov., and a rare interesting form, Xanthidium superbum Elfving var. centricornis Prowse.  相似文献   

20.
Nematodes in Odilia and Paraheligmonelloides (Trichostrongylina: Heligmonellidae) are first recorded from Sulawesi, Indonesia, with 6 new species from the small intestine of endemic murines: Odilia sulawesiensis n. sp. and Odilia moatensis n. sp. from Rattus xanthurus; Odilia mamasaensis n. sp. and Odilia maxomyos n. sp. from Maxomys musschenbroekii; Paraheligmonelloides eropeplios n. sp. from Eropeplus canus; Paraheligmonelloides paruromyos n. sp. from Paruromys dominator. The 6 species are readily distinguished from congeners in the arrangement and number of the synlophe ridges, dilatation of cuticle, shape of the bursa copulatrix and the spicules, and length ratio of the spicules or the ovejector to body. The intestinal heligmonellid fauna of Sulawesi rats shows affinity to both Sundaland and Australian representatives, reflecting dispersal and speciation history of the nematodes and their hosts.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号