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1.
Forest or mouse shrews (Myosorex) represent a small but important radiation of African shrews generally adapted to montane and/or temperate conditions. The status of populations from Zimbabwe, Mozambique, and the north of South Africa has long been unclear because of the variability of traits that have traditionally been ‘diagnostic’ for the currently recognized South African taxa. We report molecular (mitochondrial DNA and nuclear DNA), craniometric, and morphological data from newly collected series of Myosorex from Zimbabwe (East Highlands), Mozambique (Mount Gorogonsa, Gorongosa National Park), and the Limpopo Province of South Africa (Soutpansberg Range) in the context of the available museum collections from southern and eastern Africa and published DNA sequences. Molecular data demonstrate close genetic similarity between populations from Mozambique and Zimbabwe, and this well‐supported clade (herein described as a new species, M yosorex meesteri sp. nov. ) is the sister group of all South African taxa, except for Myosorex longicaudatus Meester & Dippenaar, 1978. Populations of Myosorex in Limpopo Province (herein tentatively assigned to Myosorex cf. tenuis) are cladistically distinct from both Myosorex varius (Smuts, 1832) and Myosorex cafer (Sundevall, 1846), and diverged from M. varius at approximately the same time (2.7 Mya) as M. cafer and Myosorex sclateri Thomas & Schwann, 1905 diverged (2.4 Mya). Morphometric data are mostly discordant with the molecular data. For example, clearly distinct molecular clades overlap considerably in craniometric variables. On the other hand, extreme size differentiation occurs between genetically closely related populations in the Soutpansberg Range, which coincides with the bissection of the mountain range by the dry Sand River Valley, indicating the potential for strong intraspecific phenotypic divergence in these shrews. © 2013 The Linnean Society of London  相似文献   

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This represents the first study of the soricid community from the Early Pliocene site of Langebaanweg (LBW) which is represented by four species, two of which belong to the soricid genus Myosorex (Forest shrew). Using geometric morphometrics the two Myosorex fossil species are compared with each other, and the extant western and eastern Cape species: Myosorex varius, M. cafer and M. longicaudatus. In addition, the results from an analysis of a number of non-metric characters and linear measurements on the fossil species are presented. The mandibles of the fossil species are characterized by extremely broad teeth, ascending rami which are relatively gracile and differ in shape and size from modern species, and the existence of a number of primitive features of the mandibles and teeth. This evidence is interpreted as indicating that the two LBW Myosorex species represent an archaic lineage now extinct in southern Africa.  相似文献   

4.
Most perennial herbaceous plants are able to reproduce vegetatively as well as sexually. Sometimes, such plants may lose the capacity for sexual reproduction. We have studied the case of sterility in triploid populations (2n = 3x = 45) of Gladiolus tenuis M.Bieb. in a considerable part of its area of distribution. Initially, we recorded the presence of a large clone of G. tenuis to the east of the Volga River, as a result of isozyme analysis. We also used AFLP fingerprinting to genotype 55 samples from 10 populations of G. tenuis and one population of the closely related G. imbricutus L. This analysis revealed an extremely low genetic diversity in sterile triploid populations of G. tenuis and a rather high genetic diversity in fertile tetraploid populations (2n = 4x = 60) over most of the area of this species. Genetic distances between fertile and sterile populations of G. tenuis were similar to those between different species of gladioli. It appears that a single sterile genotype has spread vegetatively over 800 km, propagating by daughter corms. The study of the reproductive features of G. tenuis suggests that the cause of sterility may be self-incompatibility between individuals of the clone.  相似文献   

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Nesidiocoris tenuis, an omnivorous arthropod, infests plants in either the absence or presence of prey arthropods. We studied whether plant-infestation experience of N. tenuis affected its subsequent prey-finding behavior. We used sesame plants and eggplants as food plants for N. tenuis, and common cutworm (CCW) (Spodoptera litura larvae) as prey. We focused on their olfactory response to CCW-infested sesame plants versus CCW-infested eggplants in a Y-tube olfactometer. When N. tenuis adults experienced the infestation of sesame plants for one day, they preferred volatiles from CCW-infested sesame plants to those from CCW-infested eggplants. By contrast, when N. tenuis experienced the infestation of eggplants for one day, they showed no difference in their preference between the two odor sources. When the duration of the infestation of plants was increased to four days, N. tenuis that had experienced sesame plants showed a reversed response: they preferred CCW-infested eggplant volatiles, while those that had infested eggplants again showed no difference in their preference. Next, we studied the olfactory preference of N. tenuis that had previously infested plants with moth (Ephestia kuehniella) eggs. We found that irrespective of plant species and of duration of experience (either one or four days), N. tenuis adults that had previously experienced one plant species showed a significant preference for volatiles from CCW-infested plants of the same species. The blends of the volatiles emitted from CCW-infested sesame plants and those from CCW-infested eggplants were qualitatively different. Possibility to control the olfactory response of N. tenuis to certain prey-infested plant volatiles by adjusting their feeding history is discussed.  相似文献   

7.
Nesidiocoris tenuis Reuter (Heteroptera: Miridae) is an omnivorous mirid bug that preys on diverse generalist herbivorous arthropods. N. tenuis adults are attracted to volatiles from plants induced by their prey, such as tobacco cutworms (CCW) (Spodoptera litura larvae) and two-spotted spider mites (Tetranychus urticae). N. tenuis adults also induce volatiles when they infest plants. In this study, we focused on olfactory responses of N. tenuis males and females to volatiles from eggplants and sesame plants induced by conspecifics of the same or different gender by using a Y-tube olfactometer. Males were attracted to volatiles from plants of both species induced by either males or females. The male preference was biased to volatiles from plants of both species induced by females, probably because the biased response would facilitate their mate-finding. Females were attracted only to volatiles from plants of both species induced by females. Mating occurs multiple times in this species. Thus, the responses would indirectly affect mating of males and females. Slight but significant qualitative and quantitative differences were detected between the volatiles of plants of both species induced by N. tenuis females and those of the plants induced by conspecific males. N. tenuis might use such differences in their gender-specific responses.  相似文献   

8.
Mitochondrial DNA control region of Mus terricolor, three aboriginal species M. spretus, M. macedonicus, M. spicilegus; the Asian lineage M. caroli, M. cervicolor, M. cookii; and the two house mice, M. musculus domesticus and M. m. castaneus were analysed to estimate the substitution rate, phylogenetic relationship and the probable time of divergence. Results showed that M. spretus, M. caroli and M. terricolor are highly diverged from each other (caroli/terricolor = 0.146, caroli/spretus = 0.147 and terricolor/spretus = 0.122), whereas M. spretus showed less divergence with two house mice species (0.070 and 0.071). Sequence divergence between M. terricolor and the Palearctic group were found to be ranging from 0.121 to 0.134. Phylogenetic analysis by minimum evolution, neighbour-joining, unweighed pair group method with arithmetic mean and maximum parsimony showed almost similar topology. Two major clusters were found, one included the Asian lineage, M. caroli, M. cookii and M. cervicolor and the other included the house mice M. m. domesticus, M. m. castaneus and the aboriginal mice M. macedonicus and M. spicilegus along with M. spretus, forming the Palearctic clade. M. terricolor was positioned between the Palearctic and Asian clades. Results showed that Palearctic-terricolor and the Asian lineages diverged 5.47 million years ago (Mya), while M. terricolor had split around 4.63 Mya from their ancestor. M. cervicolor, M. cookii and M. caroli diverged between 4.70 and 3.36 Mya, which indicates that M. terricolor and the Asian lineages evolved simultaneously. M. spretus is expected to have diverged nearly 2.9 Mya from their most recent common ancestor.  相似文献   

9.
The study investigated interspecific agonistic behavior of Macrotermes gilvus Hagen (Isoptera: Termitidae: Macrotermitinae) against three economically important subterranean termites in the Philippines, viz., Coptotermes gestroi Wasmann, Nasutitermes luzonicus Oshima and Microcerotermes losbanosensis Oshima. Termite-termite interactions after a 1:1 pairing experiment showed that M. gilvus workers and soldiers were highly aggressive against C. gestroi, N. luzonicus and M. losbanosensis leading to severe injury or death of the opponent termite species in a short period of time. The levels of agonism were caste and species specific. Worker termites of M. gilvus showed an equally aggressive behavior as soldiers contributing to the high mortality of opponent species used in this study. It is likely that the highly aggressive behavior of M. gilvus limits foraging activity of C. gestroi, N. luzonicus and M. losbanosensis around in-ground bait stations contributing to the low success of termite baits containing chitin synthesis inhibitors in the Philippines.  相似文献   

10.
Chusquea is a diverse but monophyletic genus of Neotropical woody bamboos from primarily montane forests that comprises four well-supported lineages: subg. Magnifoliae, subg. Platonia, subg. Rettbergia, and the Euchusquea clade (comprising subg. Swallenochloa and subg. Chusquea). However, the relationships among clades or taxa within the Euchusquea clade inferred from molecular data are mostly not congruent with those inferred from morphological evidence, consequently limiting our ability to understand species relationships. In this study we generated foliar micromorphological and anatomical data for the Chusquea ramosissima informal group (Chusquea ramosissima, C. tenella, and C. tenuiglumis), and for the putative new species from Bolivia in this group, in order to test the value of these types of data for defining species and to seek potential synapomorphies for this group. Our results demonstrate that epidermal features, mainly with regard to the stomatal apparatus, proved to be more valuable in distinguishing species than anatomical characters. The presence of horizontally elongated silica cells over the veins and adaxial arm cells with invaginations from the abaxial side was shared by all the studied species but is not unique to this group. The type of trichomes, shape of silica bodies, type of arm cells, and midrib structure may be useful to lesser degree. All four species exhibited intraspecific variation in development of the papillae on the long cells. Support for the recognition of the new species from Bolivia is provided by micromorphological characters. An identification key based on leaf blade features is provided for the four studied species.  相似文献   

11.
Recent collections of Ceratozamia from the Sierra Norte of Puebla, Mexico, point to a new undescribed species, which was previously subsumed under the concept of C. mexicana. Identification of this new species resulted from a review of three associated species: C. mexicana, C. tenuis, and C. delucana. Here we describe Ceratozamia totonacorum and provide information regarding its distribution and natural history. The Ceratozamia species from the Sierra Madre Oriental, Mexico, are circumscribed using morphological characters, including a detailed evaluation of reproductive structures such as the apex, position, color and shape of the ovulate strobilus.  相似文献   

12.
Satellite DNA repeats (or satDNA) are fast-evolving sequences usually associated with condensed heterochromatin. To test whether the chromosomal organisation of centromeric and non-centromeric satDNA differs in species with holocentric chromosomes, we identified and characterised the major satDNA families in the holocentric Cyperaceae species Rhynchospora ciliata (2n = 10), R. globosa (2n = 50) and R. tenuis (2n = 2x = 4 and 2n = 4x = 8). While conserved centromeric repeats (present in R. ciliata and R. tenuis) revealed linear signals at both chromatids, non-centromeric, species-specific satDNAs formed distinct clusters along the chromosomes. Colocalisation of both repeat types resulted in a ladder-like hybridisation pattern at mitotic chromosomes. In interphase, the centromeric satDNA was dispersed while non-centromeric satDNA clustered and partly colocalised to chromocentres. Despite the banding-like hybridisation patterns of the clustered satDNA, the identification of chromosome pairs was impaired due to the irregular hybridisation patterns of the homologues in R. tenuis and R. ciliata. These differences are probably caused by restricted or impaired meiotic recombination as reported for R. tenuis, or alternatively by complex chromosome rearrangements or unequal condensation of homologous metaphase chromosomes. Thus, holocentricity influences the chromosomal organisation leading to differences in the distribution patterns and condensation dynamics of centromeric and non-centromeric satDNA.  相似文献   

13.
In several surveys in the tropical forests in Thailand, specimens that looked morphologically similar to Metarhizium martiale and Cordyceps variegata, as well as other Metarhizium species were collected and cultured in vitro. A combined phylogeny of several genes including the small (18S) and large (28S) subunits of the ribosomal DNA, elongation factor 1-α (TEF), RNA polymerase II subunits 1 and 2 (RPB1, RPB2) genes has shown these to be new taxa in the Clavicipitaceae. Nigelia is described as a new genus closely related to Metarhizium, to the scale insect pathogens Aschersonia (Hypocrella), Samuelsia and Moelleriella, and to plant pathogens in Claviceps and Balansia, and other relatives. Nigelia comprises M. martiale and a new species Nigelia aurantiaca, which has been found infecting lepidopteran larvae and which produces pseudoimmersed, obliquely arranged, obpyriform perithecia with curved or bent ostioles and with whole (non-separating) cylindric ascospores. Metarhizium chaiyaphumense, M. kalasinense, M. prachinense, M. samlanense, and M. takense are described as new species of Metarhizium. Metarhizium martiale is transferred to Nigelia, and Paecilomyces reniformis is transferred to Metarhizium.  相似文献   

14.
Originally described as a monotypical genus with unclear taxonomic position from Sudan, Meroctenus Gemminger et Harold, 1868 is treated as a polytypical genus of the Selenophori genus group with two subgenera: Meroctenus s. str. and Xenodochus Andrewes, 1941, stat. n. (the latter was previously considered a distinct genus). Within Meroctenus, two species are recognized: M. (Meroctenus) crenulatus Chaudoir, 1843 (type species) and M. (M.) mediocris (Andrewes, 1936), comb, n., transferred to Meroctenus s. str. from Xenodochus. A new subspecies M. (M.) crenulatus orientalis subsp. n. is described from Pakistan. Diagnoses of the genus Meroctenus in new interpretation as well as of its two subgenera are discussed, and a taxonomic review of the subgenus Meroctenus s. str. with a key to the species and subspecies is provided. The following synonymy is proposed: Meroctenus Gemminger et Harold, 1868 = Paregaploa Müller, 1947, syn. n.; Meroctenus crenulatus (Chaudoir, 1843) = Egaploa (Paregaploa) conviva Müller, 1947, syn. n. Lectotypes are designated for Ctenomerus crenulatus Chaudoir, 1843 and Xenodus mediocris Andrewes, 1936.  相似文献   

15.
Mucuna comprises 105 species with an overall pantropical distribution and is divided into three subgenera: M. subg. Mucuna, M. subg. Stizolobium and M. subg. Macrocarpa. Although phylogenetic studies have supported the occurrence of three main clades, evolutionary relationships among them are not fully resolved. The objective of this study was to examine pollen grain morphology from representatives of all three subgenera and map these onto the phylogenetic trees generated by analysis of other characters. Pollen grain surface, form, size, and aperture number were compared. A Bayesian inference tree using matK sequences was constructed. The results indicate that the representatives of M. subg. Macrocarpa have the smallest pollen grains in the genus (a synapomorphic character here identified for this subgenus) and that species of subgenus Mucuna (those with umbelliform inflorescences) have the largest pollen grains. Additional morphological diversity of the pollen grain surface was noted: reticulate and/or micro-reticulate (in all three subgenera), perforate, gemmate or verrucose (only in M. subg. Mucuna). For all studied taxa, the pollen grains are triaperturate, except for two species of M. subg. Mucuna, which have tetraperturate pollen. The phylogenetic tree obtained using the matK marker resolved M. subg. Stizolobium as the earliest diverging lineage in Mucuna. Based on this phylogeny, a reticulate ornamentation pattern of the pollen surface may represent the ancestral state for the genus, while the larger pollen size and the foraminate, gemmate, and verrucose ornamentations are derived characteristics within the genus. These putative derived ornamentations have been observed only in neotropical species.  相似文献   

16.
We did a phylogenetic analysis on 21 of the 23 species of Stigmatopteris, a neotropical montane genus of wet forest floors. The analysis was based on four plastid markers: rbcL, rps4-trnS, trnG-trnR, and trnL-trnF. Two of the most closely related families to the Dryopteridaceae (Didymochlaenaceae and Hypodematiaceae) and 12 dryopteroid genera were used as outgroups. Eight morphological characters were mapped on the resulting tree. Stigmatopteris was recovered as monophyletic and sister to a clade formed by polystichoid ferns such as Arachniodes, Dryopteris, and Polystichum. Synapomorphies that distinguish Stigmatopteris are 1-pinnate-pinnatifid laminae, visible punctate glands in the mesophyll, the presence of hydathodes, uniseriate cilia on the scale margins, and loss of indusia. Within the genus are two main clades. The first consists of four species characterized by pinnae long-decurrent in at least the distal third of the lamina. The second consists of the remaining 17 species in the analysis and has no known morphological synapomorphies. Nested within this second clade is a subclade of six species endemic to southeastern Brazil. Anastomosing veins, a character often used in keys to distinguish the species, evolved three times within the genus.  相似文献   

17.
Two new species of Metarhizium, M. bibionidarum and M. purpureogenum are described from Japan. Metarhizium bibionidarum is the phylogenetic sister species of M. pemphigi and a member of the M. flavoviride species complex. It is distinguished morphologically from M. pemphigi by its larger conidia. The species is based on a collection of an infected March fly larva (Diptera: Bibionidae) but is also known to occur on fruit beetle (Coleoptera: Scarabaeidae) encountered in France. Metarhizium purpureogenum was isolated from soil by plating and insect baiting methods and represents a unique phylogenetic lineage placed outside the M. anisopliae and M. flavoviride species complexes. Three isolates of M. purpureogenum excreted a distinctive red-purple pigment into agar medium when co-cultured with M. robertsii or Aspergillus oryzae.  相似文献   

18.
The sorbitol-6-phosphate dehydrogenase gene (S6PDH) sequences of eight tribe Pyreae species (Rosaceae) are studied for the first time. The exon–intron structure and polymorphism of the nucleotide and amino acid sequences of this gene are characterized. The interspecific polymorphism of the S6PDH coding sequences in the studied Pyreae species is 8.36%. Sorbitol-6-phosphate dehydrogenase gene expression in S. aucuparia, A. melanocarpa, and M. domestica (cv. Skala) leaves is studied. The highest level of S6PDH expression is detected in mature leaves.  相似文献   

19.
The karyotype of the great sculpin, Myoxocephalus polyacanthocephalus (Pallas, 1814) (Pisces: Cottidae) from the Sea of Okhotsk and the Sea of Japan has been studied for the first time. The karyotype is stable; it consists of 40 chromosomes (4 metacentric, 2 submeta-subtelocentric, 20 subtelocentric, and 14 acrocentric chromosomes); the number of chromosomal arms is 44 + 2. Nucleolar organizer regions (NOR) are found in the telomeric region of the arm in one homologue of a pair of small metacentric chromosomes, using the Ag-NOR banding technique. A comparative analysis of the karyotype of M. polyacanthocephalus and the karyotypes of other Myoxocephalus species (M. stelleri, M. brandtii, M. jaok, M. ochotensis, and M. scorpius) has been carried out based on the main karyotype characters, as well as on the number and localization of NORs. The identified differences make it possible to differentiate the studied species, whereas the general traits indicate their taxonomic proximity.  相似文献   

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