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1.
Two new species of Gracilariopsis from the Indian Ocean are proposed—Gracilariopsis (Gp.) mclachlanii Buriyo, Bellorin et M. C. Oliveira sp. nov. from Tanzania and Gracilariopsis persica Bellorin, Sohrabipour et E. C. Oliveira sp. nov. from Iran—based on morphology and DNA sequence data (rbcL gene and SSU rDNA). Both species fit the typical features of Gracilariopsis: axes cylindrical throughout, freely and loosely ramified up to four orders, with an abrupt transition in cell size from medulla to cortex, cystocarps lacking tubular nutritive cells and superficial spermatangia. Nucleotide sequence comparisons of rbcL and SSU rDNA placed both species into the Gracilariopsis clade as distinct species from all the accepted species for this genus, forming a deeply divergent lineage together with some species from the Pacific. The new species are very difficult to distinguish on morphological grounds from other species of Gracilariopsis, stressing the importance of homologous molecular marker comparisons for the species recognition in this character‐poor genus.  相似文献   

2.
Delineation of species in the economically important agarophyte genera Gracilaria and Gracilariopsis has proven extremely difficult using available morphological characteristics. In this study, we examine the usefulness of two transcribed spacers for molecular systematic studies of these genera. The polymerase chain reaction was used to amplify the internal transcribed spacers (ITSs) and the intervening 5.8S ribosomal DNA of the nuclear ribosomal repeat region. In addition, a plastid spacer region and flanking regions of coding genes were amplified from the RUBISCO operon. Both regions were sequenced for individuals and populations of Gracilariopsis lemaneiformis (Bory) Dawson, Acleto, et Foldvik to determine the usefulness of these spacers in delimiting populations. These studies reveal that there is as much variation among individuals of a population as there is between individuals of geographically separate populations. In addition, the ITS spacer regions were compared between different species of Gracilariopsis and Gracilaria. The nuclear ITS spacer region is conserved at a species level in both genera and provides phylogenetically informative characters that can be used to examine species interrelationships among relatively closely related taxa. However, because of the difficulties of aligning this entire region among species from the two genera, the ITS region is not useful for examining intergenera relationships. ITS interspecies sequence comparisons indicate that Gracilariopsis lemaneiformis from California is significantly different from G. lemaneiformis from China and that a species of Gracilariopsis from Peru is more closely related to G. lemaneiformis from North Carolina than it is to the other Gracilariopsis species examined. In addition, these studies indicate that Gracilaria chilensis Bird, McLachlan, et Oliveira from New Zealand and Gracilaria tenuistipitata Chang et Xia from southeast Asia are as closely related as are Gracilaria verrucosa (Hudson) Papenfuss, G. pacifica Abbott, and Gracilaria robusta Kylin. Phylogenetic analysis of aligned plastid spacer sequences from Gracilaria and Gracilariopsis taxa provide similar conclusions about species relationships.  相似文献   

3.
The vegetative organization and reproductive development of Gracilariopsis lemaneiformis (Bory) Dawson, Acleto et Foldvik [including Gracilaria sjoestedtii Kylin] were investigated. Our observations on spermatangial development and post-fertilization features establish that Gracilariopsis Dawson is distinct at the generic level from Gracilaria Greville, and ice propose the resurrection of Gracilariopsis Dawson as a result. Spermatangial parent cells of Gracilariopsis are superficial, initiated in pairs or groups of three by concavo-convex longitudinal and transverse divisions. Each spermatangial parent cell cuts off a single, colorless spermatangium distally by a transverse division. The female reproductive apparatus consists of a supporting cell that bears a two-celled carpogonial branch flanked by two sterile branches, as in Gracilaria. Likewise, up to six sterile cells fuse with the carpogonium after fertilization to produce a primary fusion cell that generates the gonimoblasts; however, a secondary fusion cell is absent. Inner gonimoblast cells unite with cytologically modified cells of the inner pericarp by means of secondary pit-connections. Tubular nutritive cells are absent. The gonimoblast consists of a central sterile tissue interconnected throughout by secondary pit-connections surmounted by a fertile layer composed of carposporangia aligned in straight chains. The distribution of Gracilariopsis is extended to Western Europe.  相似文献   

4.
Two new species of the red algal genus Predaea are described from Australia. The first, Predaea aurora Kraft et G.W. Saunders, sp. nov., is unusual in its cool‐temperate distribution and in a number of anatomical attributes, most notably the rhizoid‐like habit of the nutritive filaments associated with the auxiliary cells. The second species, Predaea tumescens Kraft et G.W. Saunders, sp. nov., inhabits a coral reef habitat more typical of the genus but nonetheless differs in a number of anatomical details from other reported species. Nuclear small subunit rDNA sequences have confirmed the affinity of P. aurora to other species currently included in this genus. Molecular analyses further indicate that Predaea belongs in the Nemastomataceae and that the Nemastomataceae and Schizymeniaceae are sister taxa in an independent clade of “lineage 4” florideophyte algae. As such, a proposal is made to resurrect the Nemastomatales Kylin emend. G.W. Saunders et Kraft to accommodate these two families. Within the Schizymeniaceae, the Australian‐endemic Platoma australicum and Platoma foliosum were only distantly related to the other included Platoma, Schizymenia, and Titanophora spp. We therefore propose Wetherbeella G.W. Saunders et Kraft, gen. nov., to accommodate these two species. An additional outcome of our molecular analyses is that the genus Tsengia is not a member of the Nemastomataceae (where it is currently placed) but rather forms an independent lineage in the Halymeniales that we now designate as the Tsengiaceae G.W. Saunders et Kraft, fam. nov. Finally, the South African Nemastoma lanceolatum J. Agardh is transferred to Tsengia.  相似文献   

5.
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7.
Chromosome numbers of 1 N=24 were determined for three species of Gracilaria (G. flabelliforme P. Crouan et H. Grouan ex Schramm et Maze, G. mammillaris Montagne and G. tikvahiae McLachlan) and 1 N=32 for two species of Gracilariopsis (G. lemaneiformis (Bory) Dawson, Acleto et Folvik and G. tenuifrons (Bird et Oliveira) Fredericq et Hommersand). Karyotypes for these species exhibit a characteristic size difference between largest and smallest chromosomes. Polyvalents were a common feature of meiotic nuclei. Microspectrophotometry with the DNA-localising fluorochrome DAPI was used to quantify nuclear genome sizes. A 2 C genome size of 0·37–0·40 pg was determined for five species of Gracilaria (G. chilensis Bird, McLachlan et Oliveira, G. flabelliforme, G. mammillaris, G. pacifica Abbott, G. tikvahiae) and 0·33 pg for an isolate of G. verrucosa (Hudson) Papenfuss from Pas de Calais, France. Species of Hydropuntia (H. cornea (J. Agardh) Wynne and H. dentata (J. Agardh) Wynne) and Gracilariopsis (G. lemaneiformis and G. tenuifrons) were found to have slightly larger 2 C genome contents of 0·42–0·47 pg. No intraspecific variation in 2 C genome sizes was found in regional populations of Gracilaria tikvahiae and Gracilariopsis tenuifrons.  相似文献   

8.
We sequenced the small subunit rDNA and internal transcribed spacer region of Gracilariaceae from the tropical Atlantic and Pacific, with emphasis on flattened or compressed species. Sequence comparisons confirmed three main lineages of Gracilariaceae: Curdiea/Melanthalia, Gracilariopsis/Gracilariophila, and Gracilaria. The Curdiea/Melanthalia diverged early in the family. Gracilariopsis was paraphyletic, because at least one Gracilariophila species evolved from it. The Atlantic Gracilariopsis were monophyletic and separated from the Pacific lineages. The Gracilaria included all species referable to its own species and to Hydropuntia, which was paraphyletic, formed by distantly related lineages. The new combination Gracilaria pauciramosa (N. Rodríguez Ríos) Bellorin, M. C. Oliveira et E. C. Oliveira is proposed for Polycavernosa pauciramosa N. Rodríguez Ríos. Recognition of subgenera within Gracilaria, based on spermatangial arrangement, was not supported. Instead, infrageneric groups were delineated by geographic origins and combinations of reproductive characters. Most Pacific species with either “textorii” or “verrucosa” type spermatangia were deeply separated from Atlantic species. Within the Atlantic Gracilaria, a lineage encompassing mostly tropical cylindrical species with “henriquesiana” type spermatangia and distinctive cystocarp anatomy was recognized. A lineage was also retrieved for cold water stringy species with verrucosa type spermatangia. Several species from the western Atlantic are closely related to Gracilaria tikvahiae McLachlan with nearly identical morphology. On the other hand, most flattened species from the tropical Atlantic were closely related despite their diverse morphologies. The interpretation of our data in addition to the literature indicates that more populations from the Indo‐Pacific must be studied before a general picture of Gracilariaceae evolution can be framed.  相似文献   

9.
Southern Africa has economically exploited populations of terete gracilarioids on the cool temperate west coast and numerous species of endemic and Indo‐Pacific tropical Gracilariaceae on the south and east coasts. Gross morphological characters have been the main means of identification, and incorrect applications have led to a number of misidentifications. In this study, small subunit rDNA and RUBISCO spacer sequences were used to determine phylogenetic relationships. Whereas rDNA sequences successfully differentiate major groups within the family as well as species belonging to the Gracilariopsis and the Curdiea/Melanthalia clade, RUBISCO spacer sequencing was required to distinguish between species of Gracilaria. The southern African gracilarioid complex (stringy, terete, elongate members of the Gracilariaceae) was resolved into three species: Gracilaria gracilis, Gracilariopsis longissima, and Gracilariopsis funicularis. South African Gracilaria protea was shown to be conspecific with tropical Indian Ocean G. corticata. Apart from G. gracilis and G. corticata, South African Gracilaria species were differentiated into a temperate‐tropical terete grouping and a temperate‐tropical flattened grouping.  相似文献   

10.
A new genus, Augophyllum Lin, Fredericq et Hommersand gen. nov. related to Nitophyllum, tribe Nitophylleae, subfam. Nitophylloideae of the Delesseriaceae, is established to contain the type species Augophyllum wysorii Lin, Fredericq et Hommersand sp. nov. from Caribbean Panama; Augophyllum kentingii Lin, Fredericq et Hommersand sp. nov. from Taiwan; Augophyllum marginifructum (R. E. Norris et Wynne) Lin, Fredericq et Hommersand comb. nov. (Myriogramme marginifructa R. E. Norris et Wynne 1987) from South Africa, Tanzania, and the Sultanate of Oman; and Augophyllum delicatum (Millar) Lin, Fredericq et Hommersand comb. nov. (Nitophyllum delicatum Millar 1990 ) from southeastern Australia. Like Nitophyllum, Augophyllum is characterized by a diffuse meristematic region, the absence of macro‐ and microscopic veins, procarps consisting of a supporting cell bearing a slightly curved four‐celled carpogonial branch flanked laterally by a cover cell and a sterile cell, a branched multicellular sterile group after fertilization, absence of cell fusions between gonimoblast cells, and tetrasporangia transformed from multinucleate surface cells. Augophyllum differs from Nitophyllum by the blades becoming polystromatic inside the margins, often with a stipitate cylindrical base, the possession of aggregated discoid plastids neither linked by fine strands nor forming bead‐like branched chains, spermatangia and procarps initiated at the margins of blades, not diffuse, and a cystocarp composed of densely branched gonimoblast filaments borne on a conspicuous persistent auxiliary cell with an enlarged nucleus. Analyses of the rbcL gene support the separation of Augophyllum from Nitophyllum. An investigation of species attributed to Nitophyllum around the world is expected to reveal other taxa referable to Augophyllum.  相似文献   

11.
Combined phylogenetic, physiological, and biochemical approaches revealed that differences in defense‐related responses among 17 species belonging to the Gracilariaceae were consistent with their evolutionary history. An oxidative burst response resulting from activation of NADPH oxidase was always observed in two of the subgenera of Gracilaria sensu lato (Gracilaria, Hydropuntia), but not in Gracilariopsis and in species related to Gracilaria chilensis (“chilensis” clade). On the other hand, all species examined except Gracilaria tenuistipitata var. liui and Gracilariopsis longissima responded with up‐regulation of agar oligosaccharide oxidase to an challenge with agar oligosaccharides. As indicated by pharmacological experiments conducted with Gracilaria chilensis and Gracilaria sp. “dura,” the up‐regulation of agar oligosaccharide oxidase involved an NAD(P)H‐dependent signaling pathway, but not kinase activity. By contrast, the activation of NADPH oxidase requires protein phosphorylation. Both responses are therefore independent, and the agar oligosaccharide‐activated oxidative burst evolved after the capacity to oxidize agar oligosaccharide, probably providing additional defensive capacity to the most recently differentiated clades of Gracilariaceae. As demonstrated with Gracilaria gracilis, Gracilaria dura, and Gracilariopsis longissima, the different responses to agar oligosaccharides allow for a fast and nondestructive distinction among different clades of gracilarioids that are morphologically convergent. Based upon sequences of the chloroplast‐encoded rbcL gene, this study suggests that at least some of the samples from NW America recorded as Gs. lemanaeiformis are probably Gs. chorda. Moreover, previous records of Gracilaria conferta from Israel are shown to be based upon misidentification of Gracilaria sp. “dura,” a species that belongs to the Hydropuntia subgenus.  相似文献   

12.

Glyptodonts (Xenarthra, Cingulata) are one of the most amazing Cenozoic South American mammals, with some terminal forms reaching ca. two tons. The Paleogene record of glyptodonts is still poorly known, although some of their diversification is observable in Patagonian Argentina. Since the early and middle Miocene (ca. 19–13 Ma), two large clades can be recognized in South America. One probably has a northern origin (Glyptodontinae), while the other one, called the “austral clade”, is interpreted to have had an austral origin, with the oldest records represented by the “Propalaehoplophorinae” from the late early Miocene of Patagonian Argentina. In this scenario, the extra-Patagonian radiations are still poorly known, despite their importance for understanding the late Miocene and Pliocene diversity. Here, we carry out a comprehensive revision of late Miocene (Chasicoan Stage/Age) glyptodonts of central Argentina (Buenos Aires and San Juan provinces). Our results show that, contrary to what is traditionally assumed, it was a period of very low diversity, with only one species recognized in this region, Kelenkura castroi gen et sp. nov. Our phylogenetic analysis shows that this species represents the sister taxon of the remaining species of the “austral clade”, representing the first branch of the extra-Patagonian radiation. Additionally, K. castroi is the first taxon showing a “fully modern” morphology of the caudal tube.

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13.
We investigated the reproductive morphology of representative material corresponding to the type species of each of the described genera presently placed in synonymy under Gracilaria. From these observations and published studies of recognized genera, 10 species groups are identified in the Gracilariaceae based on spermatangial type and cystocarp development. Actual or potential generic names are given in brackets after each group: 1) abscissa group (Melanthalia), 2) flabellata group (Curdiea), 3) lemaneiformis group (Gracilariopsis), 4) chilensis group, 5) edulis group (Plocaria/Polycavernosa), 6) urvillei group (Hydropuntia), 7) crassissima group, 8) salicornia group (Corallopsis), 9) gracilis group, and 10) bursa‐pastoris group (Gracilaria). Tyleiophora was shown to belong to the bursa‐pastoris group. The type species of the parasitic genera Gracilariophila and Congracilaria are closely related to their host species. Species assemblages recognized here based on morphological evidence received moderate to strong bootstrap support in recently published molecular phylogenies. Further studies may show that some groups correspond to genera, whereas others do not merit generic status.  相似文献   

14.
The freshwater red algal order Thoreales has triphasic life history composed of a diminutive diploid “Chantransia” stage, a distinctive macroscopic gametophyte with multi‐axial growth and carposporophytes that develop on the gametophyte thallus. This order is comprised of two genera, Thorea and Nemalionopsis. Thorea has been widely reported with numerous species, whereas Nemalionopsis has been more rarely observed with only a few species described. DNA sequences from three loci (rbcL, cox1, and LSU) were used to examine the phylogenetic affinity of specimens collected from geographically distant locations including North America, South America, Europe, Pacific Islands, Southeast Asia, China, and India. Sixteen species of Thorea and two species of Nemalionopsis were recognized. Morphological observations confirmed the distinctness of the two genera and also provided some characters to distinguish species. However, many of the collections were in “Chantransia” stage rather than gametophyte stage, meaning that key diagnostic morphological characters were unavailable. Three new species are proposed primarily based on the DNA sequence data generated in this study, Thorea kokosinga‐pueschelii, T. mauitukitukii, and T. quisqueyana. In addition to these newly described species, one DNA sequence from GenBank was not closely associated with other Thorea clades and may represent further diversity in the genus. Two species in Nemalionopsis are recognized, N. shawii and N. parkeri nom. et stat. nov. Thorea harbors more diversity than had been recognized by morphological data alone. Distribution data indicated that Nemalionopsis is common in the Pacific region, whereas Thorea is more globally distributed. Most species of Thorea have a regional distribution, but Thorea hispida appears to be cosmopolitan.  相似文献   

15.
The Clinus superciliosus complex comprises six closely related species. Three of the species were originally recognized by Gilchrist and Thompson as two distinct species, Clinus superciliosus (Linnaeus, 1758) and Clinus ornatus Gilchrist & Thompson, 1908, and a variety, Clinus superciliosus var. arborescens Gilchrist & Thompson, 1908. A number of other authors described various similar species, which subsequently were all synonymized with Clinus superciliosus. A further species, Clinus spatulatus Bennett, 1983, an obligate estuarine dweller, is known only from the Bot, Kleinmond, and Klein river estuaries in the Western Cape, South Africa. Two further species, Clinus musaicus sp. nov. (discovered while searching for C. ornatus specimens) and Clinus exasperatus sp. nov. , are herein described: the first is currently known from False Bay and the west coast of the Cape Peninsula, whereas the second species is known from only two specimens just east of False Bay. Clinus ornatus and Clinus arborescens Gilchrist & Thompson, 1908 are recognized as a valid species, and can be distinguished from C. superciliosus and C. spatulatus on the basis of meristic values, form of the orbital cirrus, position of the dorsal‐fin crest, taste bud number and pattern, diet, and coloration. All extant types of C. superciliosus are examined as specimens, or photographs and radiographs, and their validity and identification are assessed. Genetic analysis of mitochondrial and nuclear DNA supports species differentiation. A key is provided for the species complex. Furthermore, the variable coloration of four of the species, probably related to the substrate the larvae settle upon, and the increase in the number of vertebrae, and fin‐ray and spine number, with decreasing water temperature is discussed. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society 2012, 166 , 827–853.  相似文献   

16.
Protoplasts were isolated from Ulva rigida C. Agardh (Chlorophyta) and two species of Rhodophyta , Gracilariopsis lemaneiformis ( Bory) Dawson, Acleto et Folvik and Gracilaria tenuistipitata Chang et Xia var . liui with minor modifications (the inclusion of 0.01% agarase in the set of cell-wall-degrading enzymes for the two red algae). Flow cytometric characteristics of freshly isolated protoplasts were determined on a FACScan flow cytometer (FC). The most useful parameters for characterizing protoplasts from marine algae were forward angle light scatter (FSC), orange fluorescence (FL2) and red fluorescence (FL3). Protoplasts from all the species were easily distinguishable when their FSC, FL2, and FL3 signals were combined in the bivariate plots FL3 vs. FSC and FL3 us. FL2. Two alternative techniques to help identify protoplasts from debris in the FC computer screen were developed (for FC without sorting capability). Both techniques were based on the ability of new FCs to record time. The first one was based on the induction of rapid changes of cell volume in response to osmotic stress. Only intact protoplasts responded to changes in the osmotic pressure. The second one was based on the uptake and hydrolysis of fluorescein diacetate by intracellular esterases. Viable protoplasts showed a hyperbolic accumulation of fluorescein with time. Semimaximal fluorescein accumulation was attained in 30.5 ± 9.5 s. Debris was easily recognized since, contrary to protoplasts, it did not show a time-dependent accumulation of fluorescein .  相似文献   

17.
The reproductive patterns (birth seasonality, litter size, litters per year) of two sympatric species of galago (Galago zanzibaricus and G. garnettii) were studied in a coastal forest in Kenya for a two-year period. Trap-retrap and radio tracking methods were employed. G. zanzibaricus has one infant twice per year; G. garnettii has one infant once per year. Both species are seasonal breeders. These East African galagos are intermediate in reproductive patterns when compared with galagos from South African woodland (G. senegalensis moholi and G. crassicaudatus umbrosis) and West African rainforest (G. alleni and G. demidovii). Climatic patterns (total annual rainfall, seasonal variability of rainfall, variability in total annual rainfall, and annual temperature variability) are also compared for the three regions. Climatically, East Africa is intermediate between West and South Africa in total annual rainfall and in seasonality of rainfall, but not in year-to-year variability in rainfall. East Africa shows the highest variability in annual rainfall. South Africa has the coldest dry seasons and highest variability in temperatures. The results of this study suggest that “r-selection” and “K-selection” do not provide adequate explanations of galago reproductive patterns.  相似文献   

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Red algal parasites are common and have a unique type of development in which parasite nuclei are transferred to host cells and “control” host cell development. Previous phylogenetic studies have concentrated on parasites closely related to their hosts, termed adelphoparasites. A second set of parasites, usually classified in a different family or tribe from their host, termed alloparasites, have not been studied phylogenetically. This study concentrates on the wholly parasitic family, the Choreocolacaceae (Gigartinales). Using small subunit rDNA sequence data, we found that all the parasites studied are within the same family as their host. Our data support the placement of Holmsella, species of which parasitize Gracilaria and Gracilariopsis, in the order Gracilariales and suggest that Holmsella is an old parasitic genus. Most other species of the Choreocolacaceae parasitize species of the Rhodomelaceae. The one exception is the hyperparasitism between Harveyella mirabilis (Reinsch) F. Schmitz et Reinke (Rhodomelaceae) and the parasite Gonimophyllum skottsbergii Setchell (Delesseriaceae). The parasites Bostrychiocolax australis Zuccarello et West and Dawsoniocolax bostrychiae (Joly et Yamaguishi‐Tomita) Joly et Yamaguishi‐Tomita are placed within the tribe Bostrychiae as are their hosts. Harveyella mirabilis has a single origin and has switched hosts several times during its passage between the Atlantic and Pacific Oceans. Evidence does not support the continued recognition of the family Choreocolacaceae. Our results also indicate that the distinction between adelphoparasites and alloparasites is unwarranted, with a continuum between newly evolved parasites closely related to their hosts and parasites less closely related to their hosts.  相似文献   

20.
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