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1.
H. Ota  T. Hikida  K. -Y. Lue 《Genetica》1989,79(3):183-189
Karyological survey for populations of Hemidactylus stejnegeri, a triploid parthenogenetic gecko recently described from Taiwan, revealed the occurrence of chromosomal variation in this species within Taiwan. The significance of the present findings to the process of divergence in the Hemidactylus garnotiivietnamensis complex are discussed.  相似文献   

2.
Across the Pacific the invading gecko species Hemidactylus frenatus has competitively displaced the resident gecko species Lepidodactylus lugubris in urban/surburban habitats. Do parasites enhance, inhibit, orhave no effect on this invasion? Parasites can confer an advantage to an invading species when the invader (1) introduces a new parasite to a resident species that has a greater detrimental effect on the resident than the invader, (2) is less susceptible to endemic parasites than the resident, and/or (3) increases the susceptibility of the resident to parasites. Conversely, parasites may protect a resident against invasion when endemic parasites have a greater impact on the invader than the resident. We screened more than one thousand H. frenatus and L. lugubris in areas of sympatry and allopatry from 28 islands and 5 sites on mainland Asia for a broad array of blood parasites, coccidia and helminths in order to evaluate the potential for parasites to affect their interaction. We found that 1) There were no parasites which appear to protect L. lugubris against invasion by H. frenatus. 2) H. frenatus does not introduce the same parasite to L. lugubris in every location where the two come in to contact, but probably has introduced different parasites in different locations. L. lugubris also seems to have introduced at least one parasite to H. frenatus. 3) The prevalence of parasite species shared by the two hosts is generally higher in H. frenatus; however, prevalence is determined by many factors and cannot be directly translated as susceptibility. We discuss the implications of this difference in prevalence for the Red Queen hypothesis. 4) The prevalence of the cestode Cylindrotaenia sp. is significantly higher in L. lugubris that are sympatric with H. frenatus than those which are allopatric.  相似文献   

3.
A previous study on Hemidactylus turcicus based on mtDNA makers indicated that this gecko has a Middle-East origin, and that the current phylogeographic pattern is the result of a very rapid spread from the east to the west of the species’ range. The same study identified two distinct mitochondrial lineages with low differentiation and genetic diversity. Since H. turcicus is known to be closely associated to humanized environments, its present distribution range and phylogeography is frequently interpreted to be the result of recurrent human-mediated introductions. These conclusions used to be the same as those used to interpret the results obtained for the European populations of another gecko, Tarentola mauritanica. However, a recent study has revealed that the phylogeographic pattern of T. mauritanica is not solely the result of a recent colonization, but also of a mitochondrial selective sweep. Could the same be occurring in H. turcicus? To answer this question, two mitochondrial (12S rRNA and cytochrome b) and two nuclear genes (ACM4 and Rag2) were used in this study. From the mtDNA data we confirmed the existence of two distinct phylogeographic lineages; one occurring exclusively in the northern Mediterranean (Clade A), and another one more widespread that is the only lineage present in North Africa (Clade B). In light of these results, we could hypothesize that H. turcicus had its origin in Turkey, and from there Clade A moved to Europe and Clade B to North Africa spreading latter into Europe. However, Clade A presents significantly higher nucleotide diversity for the nuclear DNA compared to the mtDNA, and neutrality tests gave significant results for the mitochondrial data. These results suggest that the lack of mtDNA genetic diversity and structure in the European population of H. turcicus could also be due to a selective sweep, and not only because of a recent colonization. Together with the situation reported in T. mauritanica, the identification of a hitch-hiking process occurring in H. turcicus, represents two unprecedented cases of a selective sweep taking place in the same geographic area shaping the phylogeographic patterns of two unrelated genera of geckos.  相似文献   

4.
Coscinium fenestratum is a critically endangered medicinal plant, well-known for its bioactive isoquinoline alkaloid berberine. The species has been over harvested from its natural habitats to meet the huge requirement of raw drug market and industrial consumption. This has lead to a rapid decline in the population size and has also led to local population extinction at few locations in the Western Ghats, India. In this study, inter-simple sequence repeat markers were used to investigate the genetic variation and population structure of seven extant populations of C. fenestratum from the central Western Ghats, India. Eight primer combination produced a total of 57 unambiguous bands, of which (47.1 %) were polymorphic. The species exhibited a moderate to low level of intra population genetic diversity (H s = 0.347 ± 0.008; H t = 0.378 ± 0.006 (POPGENE) and H s = 0.262 ± 0.0028; H t = 0.204 ± 0.020 (HICKORY)). The populations were low to moderately differentiated from one another (G ST = 0.221) and geographical distance was not significantly correlated with genetic distance, suggesting that these long-lived, geographically distant remnant populations were once connected through gene flow. There was a significant amount of genetic variation among populations (19.85 %). The Bayesian software STRUCTURE and HICKORY were used to further reveal the genetic structure of C. fenestratum. The results revealed weak population structure (K = 2) with one single widespread gene pool, and indicated that gene flow and inbreeding are likely to be the major driving force in shaping current population genetic structure of C. fenestratum. Thus, an understanding of the genetic diversity and population structure of C. fenestratum can provide insight into the conservation and management of this species.  相似文献   

5.
Among the plant life-forms, lianas, the wood climbers still remain less studied than trees. The forests of Eastern Ghats of India are also relatively under studied compared with the Western Ghats biodiversity hotspot. We conducted a large-scale, landscape-level investigation of liana diversity in six hill complexes of the South Eastern Ghats, which covers 4297 km2. We divided the study area into 6.25 km × 6.25 km grids and within each grid a 0.5 ha (5 m × 1000 m) transect was established and all lianas ≥1.5 cm diameter at breast height (dbh) were inventoried in 110 transects totalling a 55-ha area. Liana diversity totalled 143 species in 83 genera and 37 families in the 55 ha sampled. Of these 20 species (28.6%) were endemic to peninsular India and 7 (10%) species belonged to the rare and endangered category. Liana species richness ranged from 8–35 species and density 95–544 individuals per transect. A total of 32 033 liana individuals were enumerated in the 55 ha and the mean abundance was 291 individuals per transect. Across sites, liana abundance varied significantly, but not species richness and basal area. Asclepiadaceae (13 species, 9%) and Apocynaceae (11 species, 8%) constituted the most diverse liana families, followed by Papilionaceae, Vitaceae (10 each, 7%), Convolvulaceae, Mimosaceae, Oleaceae (8 each, 6%), Capparaceae, Rhamnaceae (7 each, 5%) and Menispermaceae (5 species, 3%). In liana stem size distribution, the lowest diameter class (1.5–3 cm dbh) accounted for greatest species richness (137 species, 96%), abundance (27 358 individuals, 85%) and basal area (13.5 m2, 36%). The stem twiners were the predominant climber type in terms of species richness (61 species, 42.65%), whereas the armed scramblers were abundant due to stem density (21 571 individuals, 67.34%). The dispersal modes of lianas, assessed by fruit types, revealed zoochory as the prevalent mode (85 species, 59%) indicating the faunal dependence of lianas in the Eastern Ghats landscape. Liana diversity of the Eastern Ghats was compared with inventories made across the tropics. With these baseline data generated on lianas, the importance of biodiversity conservation of the already fragmented South Eastern Ghats region is underlined and potential areas of further research on liana ecology are suggested.  相似文献   

6.
We detected that Galaxias maculatus exhibits a pattern where metabolic activity increases after sunrise and peaks between noon and sunset, but this species feeds in the afternoon, until several hours after sunset. Moreover, we showed that G. maculatus is observed in the littoral zone during the day, disappears completely from this zone after sunset and returns at sunrise. Littoral prey species are common in the diet of G. maculatus, but this study showed that pelagic prey is also present during twilight and night hours in smaller individuals (<50 mm), which is related to habitat use. These behavioural rhythms are especially important for G. maculatus, which runs a high predation risk when consuming prey that is widely available outside the littoral zone. This risk is ameliorated under the protection of low light intensity. Thus, G. maculatus is a key species linking lower trophic levels, such as the plankton community, to higher levels of native and exotic piscivores. These displacements of G. maculatus generate an active flow of energy and matter between habitats, with a potentially profound effect on the entire food network and energy dynamics of the lake.  相似文献   

7.
Hemidactylus brookii, a gecko possessing great dispersal ability, has apparently spread from West Africa to the Caribbean and South America by natural rafting. The lungs of populations from West Africa and the Greater Antilles (hispaniola and Puerto Rico) are heavily infected by raillietiellied pentastomids. Nigerian populations harbour two distinct species, frequently as concurrent infections, the males of which can be separated principally by marked differences in the morphology of the copulatory spicule. However one of these species cannot be reliably distinguished from Raillietiella teagueselfi, a common parasite of another highly successful coloniser, the Mediterranean gecko H. turcicus in Texas. The other more closely resembles R. frenatus, first described from the lungs of yet another itinerant gecko (H. frenatus) from south east Asia. Raillietiella spp. from both the Hispaniolan and Puerto Rican H. brookii haitianus populations, possess bluntly-rounded spicules of the R. frenatus type, although comparative posterior hook dimensions indicate that they are not closely related to it, or indeed to each other. They clearly comprise recognisably different geographical populations, but it remains unclear as to whether these are endemic or introduced. Both of the Caribbean species are left unnamed because we do not know what proportion of the observed intra- and interspecific variation is genetically based. Analysis of another raillietiellid population from an African skink (Mabuya perrotetii) is also included because it harbours two more species which are not easily distinguished from R. frenatus and R. teagueselfi. More refined diagnostic techniques, ultimately supplemented by life-cycle studies, are required to resolve these taxonomic problems.  相似文献   

8.
Competition over spatial niche utilisation is one of most common competitive interactions between species in sympatry. Moreover, competitive interactions may involve age classes, and can fluctuate temporally. Consequently, evasive strategies that enable co-existence are likely to be important in the evolution of species assemblages. Here we investigate a system of two co-existing species of temperate geckos with similar ecologies (the house gecko, Hemidactylus turcicus and the wall gecko, Tarentola mauritanica), providing an opportunity to study the effect of species interactions. Juveniles and adults of both species were investigated throughout their daily and annual cycle to explore the effect of inter- and intra-specific interactions on microhabitat use. The two species showed differences in habitat use for both age classes in sympatry. In sympatry, T. mauritanica uses more open habitats and is more active. In contrast, H. turcicus is found in more closed habitats, closer to the ground and to vegetation cover. In allopatry, H. turcicus was observed in more open habitats, closer to the ground, and to vegetation cover, when compared to the population in sympatry with T. mauritanica. These differences in habitat usage were significant for both age classes. Moreover, there were differences, both in sympatry and in allopatry, between age classes that were dependent on season. In conclusion, the presence of a competitor induces a spatial shift in individuals of both age classes of H. turcicus. Observed plasticity in habitat utilisation in both age classes of H. turcicus is used to argue for the invasive potential of this species.  相似文献   

9.
A recent molecular phylogeny of the Arid clade of the genus Hemidactylus revealed that the recently described H. saba and two unnamed Hemidactylus species from Sinai, Saudi Arabia and Yemen form a well-supported monophyletic group within the Arabian radiation of the genus. The name ‘Hemidactylus saba species group’ is suggested for this clade. According to the results of morphological comparisons and the molecular analyses using two mitochondrial (12S and cytb) and four nuclear (cmos, mc1r, rag1, rag2) genes, the name Hemidactylus granosus Heyden, 1827 is resurrected from the synonymy of H. turcicus for the Sinai and Saudi Arabian species. The third species of this group from Yemen is described formally as a new species H. ulii sp. n. The phylogenetic relationships of the members of ‘Hemidactylus saba species group’ are evaluated and the distribution and ecology of individual species are discussed.  相似文献   

10.
Henneguya tunisiensis n. sp., a new myxosporean, is described from the gill-arches of the East Atlantic peacock wrasse Symphodus tinca (L.) collected from off the Kerkennah Islands, Tunisia. It is characterised by the presence of elongate white plasmodia of 1–1.5 × 1.5–2 mm in size. The mature spores are rounded in frontal view and have two identical polar capsules and two caudal appendages which taper considerably at the end. Both light and electron microscopical data show that this species differs in several morphological features from all previously described Henneguya spp. A molecular analysis, based on 18S rDNA sequence data, indicates that H. tunisiensis n. sp. is readily distinguishable from other myxozoan DNA sequences in GenBank. Phylogenetically, the new species is placed in the marine Henneguya clade, which is a sister group of marine Myxobolus spp. from perciform fishes in Tunisian waters.  相似文献   

11.
The introduction of the Asian house gecko, Hemidactylus frenatus, to mainland Australia has sparked considerable debate in regard to its potential impacts on native lizard species. Their historically patchy distribution across Australia has gained attention as populations have spread into peri‐urban and native bushland. Hemidactylus frenatus potentially pose a threat to native species through competition and predation. I documented some activity of H. frenatus during the day, including foraging, which may broaden the potential impacts to diurnal species. Here, I highlight (i) the potential impact of predation by H. frenatus on native lizards and (ii) the need for empirical studies directly quantifying competitive encounters, with special interest in intraguild predation.  相似文献   

12.
A non-pigmented, motile, Gram-negative bacterium designated H 17T was isolated from a seawater sample collected in Port Phillip Bay (the Tasman Sea, Pacific Ocean). The new organism displayed optimal growth between 4 and 37 °C, was found to be neutrophilic and slightly halophilic, tolerating salt water environments up to 10 % NaCl. Strain H 17T was found to be able to degrade starch and Tween 80 but unable to degrade gelatin or agar. Phosphatidylglycerol (27.7 %) and phosphatidylethanolamine (72.3 %) were found to be the only associated phospholipids. The major fatty acids identified are typical for the genus Alteromonas and include C16:0, C16:1ω7, C17:1ω8 and C18:1ω7. The G+C content of the DNA was found to be 43.4 mol%. A phylogenetic study, based on the 16S rRNA gene sequence analysis and Multilocus Phylogenetic Analysis, clearly indicated that strain H 17T belongs to the genus Alteromonas. The DNA?DNA relatedness between strain H 17T and the validly named Alteromonas species was between 30.7 and 46.4 mol%. Based on these results, a new species, Alteromonas australica, is proposed. The type strain is H 17T (= KMM 6016T = CIP 109921T).  相似文献   

13.
Western Ghats of India is recognized as one of the 12 mega diversity regions of the world and is the hot spot for unrevealed microbial diversity. To explore the diversity of polysaccharide degrading enzymes in that region, metagenomic library was constructed from forest soil of Southern Western Ghats region. Nine pectinolytic clones with the ability to degrade citrus pectin were isolated based on function based screening of the library. Sequence analysis of pg_4 clone containing revealed that it contained GH family 28 domain (pfam00295) belonging to polygalacturonase superfamily (PLN03003). Its amino acid sequence analysis showed 25–55 % identity to the other well-characterized polygalacturonases. Molecular modeling of pg_4 revealed that it comprised of three right handed-parallel β sheets, one anti-parallel β sheet and one α helix with three conserved catalytic residue D 2263, D 284-85 and H 312 at the C terminal end. The enzyme characterized was able to hydrolyze both apple and citrus pectin with K m values of 1.685 and 1.542 mg ml?1 and retained more that 80 % of activity at pH 5–9 and temperature 20–60 °C.  相似文献   

14.
Choleoeimeria duszynskii n. sp. is described from the gallbladder of the Middle Eastern short-fingered gecko Stenodactylus doriae (Blanford) from Salasel, Central region, Saudi Arabia. Oöcysts are ellipsoidal (rarely ovoidal), 23–25 × 16–18 (24 × 17) μm, with mean length/width ratio 1.4. Oöcyst wall is smooth, bi-layered, c.1.0 μm thick. Micropyle, oöcyst residuum and polar granule are absent. Sporocysts are ellipsoidal, 8–10 × 4–6 (9 × 5) μm, with a smooth, colourless sporocyst wall and mean length/width ratio 1.7. Sporozoites are sausage-shaped, with one end slightly pointed, arranged head to tail around sporocyst residuum. Refractile bodies and nuclei are not discernible. The endogenous development is restricted to the epithelium of the gallbladder and bile duct. Meronts are rounded, 12 μm in diameter, containing up to c.15 merozoites. Microgamonts are irregular in shape, 22 × 17 μm, containing a large number of microgametes. Macrogamonts are spherical, 17 μm in diameter, with centrally located nucleus and wall-forming bodies at the periphery.  相似文献   

15.
A new pearleye species of the alepisauroid family Scopelarchidae, Scopelarchoides neamticus sp. nov., is described herein based on two specimens from the Oligocene Lower Dysodilic Shales Formation, cropping out in the Pietricica Mountain, Romanian Eastern Carpathians. The new species described herein exhibits a unique combination of features (including head length about 25% of SL; coracoid remarkably expanded; both preorbital and postorbital lengths larger than orbit diameter; 50 or 51 vertebrae; dorsal fin with nine or ten rays; anal-fin with 28 rays; length of anal fin base about 30% of SL; preanal distance almost 60% of SL; pelvic fin insertion located just under the second dorsal fin ray; pectoral fins only slightly longer than pelvic fins; caudal fin with 19 principal rays plus 14 upper and 13 lower procurrent rays) that justifies its recognition as a new species of the genus Scopelarchoides. Both morphological and meristic features suggest a certain degree of similarity between S. neamticus sp. nov. and the extant species Scopelarchoides signifer. The fossils of the new Oligocene species described herein represent the oldest known skeletal record of Scopelarchidae.  相似文献   

16.
A new cryptic species of bush frog Raorchestes honnametti sp. nov. is described from the south-eastern part of the Western Ghats, India. This newly described species belongs to the Charius clade and is morphologically similar to other clade members—R. charius and R. griet. Therefore, an integrative taxonomic approach based on molecular and bioacoustic analysis along with morphology was used to delimit the new species. Raorchestes honnametti sp. nov., is currently known only from Biligiri Rangaswamy Temple Tiger Reserve, a part of Biligiri Rangaswamy horst mountain range (a mountain formed due movement of two faults) formed during the Late Quaternary period (1.8–2.58 Ma). Discovery of cryptic species from a highly speciose and well-studied genus Raorchestes hints at the possible existence of several more cryptic species in this genus. We discuss the possible reasons for crypsis and emphasize the need for continued systematic surveys of amphibians across the Western Ghats.  相似文献   

17.
Dysoxylum malabaricum (white cedar) is an economically important tree species, endemic to the Western Ghats, India, which is the world’s most densely populated biodiversity hotspot. In this study, we used variation at ten nuclear simple sequence repeat loci to investigate genetic diversity and fine scale spatial genetic structure (FSGS) in seedlings and adults of D. malabaricum from four forest patches in the northern part of the Western Ghats. When genetic variation was compared between seedlings and adults across locations, significant differences were detected in allelic richness, observed heterozygosity, fixation index (F IS), and relatedness (P < 0.05). Reduced genetic diversity and increased relatedness at the seedling stage might be due to fragmentation and disturbance. There was no FSGS at the adult stage and FSGS was limited to shorter distance classes at the seedling stage. However, there was clear spatial genetic structure at the landscape level (<50 km), regardless of age class, due to limited gene flow between forest patches. A comparison of the distributions of size classes in the four locations with published data from a more southern area, showed that large trees (diameter at breast height, DBH, >130 cm) are present in the southern sacred forests but not in the northern forest reserves. This pattern is likely due to stronger harvesting pressure in the north compared to the south, because in the north there are no cultural taboos regulating the extraction of natural resources. The implications for forest conservation in this biodiversity hotspot are discussed.  相似文献   

18.
Invasive geckos of the genus Hemidactylus (Gekkonidae) are spreading rapidly through urban environments in many tropical and subtropical parts of the world. The invaders have caused rapid declines in native gecko abundance in some areas, but their interactions with Australian native species remain unknown. In a small rural village near Darwin, we found that Hemidactylus frenatus is abundant around both lighted and unlighted buildings, but rarely found in surrounding bushland. It is sympatric with the larger Gehyra australis (Gekkonidae) in this disturbed site, and often forages on the same buildings, but is active mostly during the dry‐season (vs. wet‐season for G. australis) and is competitively subordinate to the larger native species. In laboratory encounters, H. frenatus fled from G. australis, and modified its refuge‐site use in the presence of the native lizard. In those same trials, the native gecko often attacked and rarely fled; and did not shift its refuge‐site selection. In field surveys, the two taxa frequently co‐occurred. However, substrate use of the invasive H. frenatus was modified by the presence of the native G. australis, consistent with competitive displacement. Our counts of H. frenatus were highest during the dry‐season, when G. australis (like most other small native reptiles) is relatively inactive. The invasive gecko thus appears to be exploiting a ‘vacant niche’ around buildings, rather than displacing the native gecko taxon. This outcome may reflect the size disparity between the native species and the invader; Hemidactylus frenatus may well have significant ecological impacts on smaller native lizards.  相似文献   

19.
The blue-spotted maskray, previously N. kuhlii, consists of up to eleven lineages representing separate species. Nine of these species (N. australiae, N. bobwardi, N. caeruleopunctata, N. malaccensis, N. moluccensis, N. orientale, N. vali, N. varidens, N. westpapuensis) have already been formally described and two (Indian Ocean maskray and Ryukyu maskray) remain undescribed. Here, the Indian Ocean maskray is described as a new species, Neotrygon indica sp. nov. Specimens of the new species were generally characterized on their dorsal side by a moderately large number of small ocellated blue spots, a low number of medium-sized ocellated blue spots, the absence of large ocellated blue spots, a high number of dark speckles, a few dark spots, and a conspicuous occipital mark. The new species formed a distinct haplogroup in the tree built from concatenated nucleotide sequences at the CO1 and cytochrome b loci. A diagnosis based on colour patterns and nucleotide sequences at the CO1 and cytochrome b loci is proposed. The distribution of N. indica sp. nov. includes the Indian coast of the Bay of Bengal, the Indian coast of the Laccadives Sea, and Tanzania. Considerable sampling effort remains necessary for an in-depth investigation of the phylogeographic structure of the Indian Ocean maskray.  相似文献   

20.
Spartina species play an important ecological role on salt marshes. Spartina maritima is an Old-World species distributed along the European and North-African Atlantic coasts. This hexaploid species (2n = 6x = 60, 2C = 3,700 Mb) hybridized with different Spartina species introduced from the American coasts, which resulted in the formation of new invasive hybrids and allopolyploids. Thus, S. maritima raises evolutionary and ecological interests. However, genomic information is dramatically lacking in this genus. In an effort to develop genomic resources, we analysed 40,641 high-quality bacterial artificial chromosome-end sequences (BESs), representing 26.7 Mb of the S. maritima genome. BESs were searched for sequence homology against known databases. A fraction of 16.91 % of the BESs represents known repeats including a majority of long terminal repeat (LTR) retrotransposons (13.67 %). Non-LTR retrotransposons represent 0.75 %, DNA transposons 0.99 %, whereas small RNA, simple repeats and low-complexity sequences account for 1.38 % of the analysed BESs. In addition, 4,285 simple sequence repeats were detected. Using the coding sequence database of Sorghum bicolor, 6,809 BESs found homology accounting for 17.1 % of all BESs. Comparative genomics with related genera reveals that the microsynteny is better conserved with S. bicolor compared to other sequenced Poaceae, where 37.6 % of the paired matching BESs are correctly orientated on the chromosomes. We did not observe large macrosyntenic rearrangements using the mapping strategy employed. However, some regions appeared to have experienced rearrangements when comparing Spartina to Sorghum and to Oryza. This work represents the first overview of S. maritima genome regarding the respective coding and repetitive components. The syntenic relationships with other grass genomes examined here help clarifying evolution in Poaceae, S. maritima being a part of the poorly-known Chloridoideae sub-family.  相似文献   

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