New Combination Of Characters Research Articles

The morphology of the reproductive system in the crab Percnon gibbesi (Decapoda: Brachyura: Grapsoidea) reveals a new combination of characters in Thoracotremata.

Recent studies revealed a high diversity of reproductive structures in heterotreme brachyurans, while those of Thoracotremata seem rather uniform. Yet, there still is a huge lack of data in this group as only few species have been studied with respect to their reproductive system. The phylogenetic position of Percnidae is ambiguous. Recent molecular studies place it within polyphyletic grapsoids. We herein study the reproductive morphology of Percnon gibbesi using histology, scanning electron microscopy, micro-computed tomography and 3D-reconstructions to test whether this species shows the characteristic thoracotreme pattern. Our results reveal that the male copulatory system conforms to other thoracotremes. It is composed of two pairs of pleopods (gonopods) and likewise paired penes. The first gonopod is relatively long. It possesses a bent terminal process with a distal opening of the ejaculatory canal, a character also present in other grapsoids. The second gonopod is short and terminates in an apical girdle. The female reproductive system reveals a combination of characters, so far unknown for thoracotremes. The paired oviducts do not lead into the seminal receptacles, but run into separate cuticular ducts joined with the vaginae. Accessory sperm storage organs, the bursae, are also connected to the vaginae. Bursae have previously only been described in heterotreme crabs. The data presented in this study reveals a higher diversity of thoracotreme reproductive systems than anticipated.

A new species of Cephalodasys (Gastrotricha, Macrodasyida) from the Caribbean Sea with a determination key to species of the genus.

A new marine gastrotrich species of the genus Cephalodasys is described from shallow sublittoral coralline sand sampled between Lee Stocking Island and Norman's Pond Cay (Exuma Cays), Bahamas. Cephalodasys interinsularis n. sp. reaches a body length of 471 µm and is characterized by a new combination of characters including six total anterior adhesive tubes and five pairs of ventrolateral adhesive tubes. The new species is morphologically similar to C. swedmarki but can be distinguished by the different number of anterior adhesive tubes, the spatial arrangement of the ventrolateral adhesive tubes, and a shorter pharynx. We provide an updated diagnosis of the genus and a determination key to all known species of Cephalodasys. C. interinsularis n. sp. is the third known species of Cephalodasys from the Caribbean marine province.

Diagnosis and redescription of Panochthus subintermedius Castellanos (Xenarthra, Glyptodontia) from the Ensenadan (early-middle Pleistocene) of Buenos Aires (Argentina)

Panochthus subintermedius was originally named by Castellanos in 1933, without any diagnosis and no type material designated. In 1936, he briefly described and designated a holotype for this species (MACN-Pv 5130) and subsequently, in 1942, completed the description, but a diagnosis was still lacking. Some authors have considered this species as nomem nudum, but others have accepted its validity since 1942. In this contribution we propose that Castellanos’s 1936 paper is the valid name-establishing publication for this species. The holotype includes a large portion of dorsal carapace, the caudal tube, and remains of postcranial skeleton, belonging to a single specimen from the Ensenadan Stage/Age (early-middle Pleistocene) of Buenos Aires, Argentina. In contrast to the original description, new observations of the holotype reveal that the superficial surface of the dorsal carapace osteoderms is ornamented with small polygonal figures without a principal one. This ornamentation differs from that of P. intermedius Lydekker (the only species accepted up to now for the Ensenadan), with a central figure in most of its osteoderms. The caudal tube of P. subintermedius differs from those of the Bonaerian-Lujanian species (middle late Pleistocene–early Holocene), in having a sharper distal end, one apical dorsal figure, and a higher number of central figures along the entire dorsal surface. No caudal tube associated with the carapace of P. intermedius is known. Accordingly, P. subintermedius can be clearly distinguished from other Panochthini species by a unique combination of carapace and caudal tube characters. This new combination of characters provides more information on this taxon and other species of Panochthini for future studies in the interrelationships of Glyptodontia.

Exploring Complex Ornamental Genomes: The Rose as a Model Plant

Despite its high economic importance, little is known about rose genetics, genome structure, and the function of rose genes. Reasons for this lack of information are polyploidy in most cultivars, simple breeding strategies, high turnover rates for cultivars, and little public funding. Molecular and biotechnological tools developed during the genomics era now provide the means to fill this gap. This will be facilitated by a number of model traits as e.g., a small genome, a large genetic diversity including diploid genotypes, a comparatively short generation time and protocols for genetic engineering. A deeper understanding of genetic processes and the structure of the rose genome will serve several purposes: Applications to the breeding process including marker-assisted selection and direct manipulation of relevant traits via genetic engineering will lead to improved cultivars with new combinations of characters. In basic research, unique characters, e.g., the biosynthesis and emission of particular secondary metabolites will provide new information not available in model species. Furthermore comparative genomics will link information about the rose genome to ongoing projects on other rosaceous crops and will add to our knowledge about genome evolution and speciation. This review is intended as a presentation and is the compilation of the current knowledge on rose genetics and genomics, including functional genomics and genetic engineering. Furthermore, it is intended to show ways how knowledge on rose genetics and genomics can be linked to other species in the Rosaceae in order to utilize this information across genera.

Prospectives for genetic improvement of the inflorescences structure in oil crops of the Brassicaceae family

When describing the role of Arabidopsis genes AP1, BP1, and TFL1, the theoretical basement of the possibility of the genetic design of agriculturally valuable inflorescence architecture of oil crops in the Brassicaceae family was proposed. The main trend is connected with avoiding uneven development of seeds. It has been demonstrated that A. thaliana bearing recessive alleles ap1-1, bp-1, and tfl1-2 forms inflorescences with new combinations of characters instead of typical for Brassicaceae.

Morphology and cell division of the oxytrichids Architricha indica nov. gen., nov. sp., and Histriculus histrio ( ), (Ciliophora, Hypotrichida)

The oxytrichid ciliate Architricha indica nov. gen., nov. sp., isolated from the river Yamuna, Delhi, shows a new combination of characters. It possesses a flexible body, 18 frontal–ventral–transverse (FVT) cirri, 3 right and 2 left marginal cirral rows, 6 dorsal bristle rows and 3 caudal cirri (CC). The FVT cirri arise from 6 primordia, which utilize 6 parental cirri in their origin as is typical of Oxytricha species. Multiple marginal rows (MMR) develop through 5 independent marginal primordia arising “within-row”, 1 in each parental marginal row. All the 5 marginal rows are thus morphogenetically active. Such a mode of formation of MMR has not been recorded among oxytrichids and has necessitated separation of A. indica at the generic level. Histriculus, on the other hand, has well-known characteristics, viz. rigid body, confluent marginal rows and absence of CC. The morphogenesis of Histriculus histrio has been described by Berger and Foissner [1997. Cladistic relationships and generic characterization of oxytrichid hypotrichs (Protozoa, Ciliophora). Arch. Protistenkd. 148, 125–155]. Reinvestigation of very early stages of development revealed that (i) the FVT cirral primordia utilize kinetosomes from 5 parental FVT cirri, (ii) the primordium II of the proter is of a composite origin: kinetosomes from the oral primordium merge with the primordium II that originates from the buccal cirrus II/2 and (iii) the FVT primordia V and VI for the 2 daughter cells arise sequentially from the parental cirrus V/4. Thus, the genus Histriculus exhibits a new combination of characters with respect to the origin of FVT cirri, an additional pattern to be added to the known 6 patterns of FVT development in oxytrichids [Berger and Foissner, 1997; Berger, H., 1999. Monograph of the Oxytrichidae (Ciliophora, Hypotrichida), Kluwer Academic Publishers, Dordrecht/Boston/London].

An aglaspidid arthropod from the Upper Ordovician of Morocco with remarks on the affinities and limitations of Aglaspidida

ABSTRACTA new aglaspidid arthropod, Chlupacaris dubia gen. et sp. nov., is described from the Pusgillian (lower Ashgill, Upper Ordovician) Upper Tiouririne Formation near Erfoud, southeastern Morocco. Although disarticulated, careful documenting of the tergites allows a reconstruction of the exoskeleton to be made. Although somewhat trilobite-like in appearance, the lack of facial sutures, a well-defined axis with articulating half-rings and a pygidium clearly prove Chlupacaris gen. nov. is not a trilobite. An interesting feature is the presence of a hypostome in this non-trilobite arthropod. In contrast to other aglaspidids usually considered to be carnivorous, a filter-feeding mode of life is proposed for Chlupacaris gen. nov., based on the strongly vaulted cephalon, subvertical orientation of the hypostome and less strongly vaulted trunk. Chlupacaris gen. nov. is probably most closely related to the atypical aglaspidid Tremaglaspis unite from the Tremadoc (Lower Ordovician) of the U.K., but it can also be tentatively linked to the problematic Lower Cambrian arthropods Kodymirus vagans and Kockurus grandis from the Czech Republic. The relevance and validity of previous definitions and of possibly significant characters used for identifying aglaspidids are evaluated, and as a result, a new combination of characters diagnosing Aglaspidida is proposed. Contrary to previous reports, it is suggested that aglaspidids are probably more closely related to trilobites than they are to chelicerates. This notion may be supported by the shared possession of a mineralised cuticle, a possibly similar number of cephalic appendages, and the presence of a hypostome in some forms, although this last character may alternatively be homoplastic.

Cyrtoctenus wittebergensissp. nov. (Chelicerata: Eurypterida), a large sweep-feeder from the Carboniferous of South Africa

ABSTRACTCyrtoctenus wittebergensissp. nov. is described from a unique holotype from the Witteberg Group of the Cape Supergroup. It is a giant hibbertopteroid eurypterid having combs and specialised movable spines of crytoctenid type (Størmer & Waterston 1968) on the more distal podomeres of the second to fourth prosomal appendages. The function of the combs and their associated movable spines is discussed and it is suggested that together they formed a unique adaptation of eurypterid structures to sweep filter-feeding, the combs forming the filters and the spines the cleaners. The digestive tract is remarkably preserved and shows a spiral valve, posterior to the stomach, which is interpreted as an adaptive feature in this large arthropod to increase the absorptive area of the gut.The new evidence provided by the South African specimen has required the re-interpretation of the disarticulatedCyrtoctenusspecimens previously described from Europe.Disjecta membrarecently obtained from the Tournaisian of Foulden, Berwickshire, which may belong toCyrtoctenus, are described and show characters previously unknown in Scottish material but similar to certain features in the South African specimen.The taxonomic relationships within the Hibbertopteroidea are discussed in the light of the new combination of characters found inC. wittebergensis. Two families are recognised in the superfamily, the Hibbertopteridae, includingHibbertopterusandCampylocephalus, and the new family Cyrtoctenidae which is here erected to includeCyrtoctenus, Dunsopterusand possibly alsoHastimima.

Anther Culture with a Sterile Interspecific Hybrid between Nicotiana tabacum and N. sylvestris

Anther culture was carried out using the sterile F1 hybrids between Nicotiana tabacum and N. sylvestris. Plantlets were developed from 3.4% of the anther. Some plants obtained showed new combinations of characters of the two parents, but they were supposed to be of the tapetum origin.

Classification of Varieties and Types of Castor (Ricinus communis L.)

Castor varieties were classified based on eco-geographical grouping and on certain morphological characters by previous workers. Eventhough none of the systems of classification could be compeleted in castor, in view of the free inter-crossability of the different varieties and forms of divergent origin, classifying the availabile material with a bias for breeding work, based on certain chosen morphological and economic attributes of known heritability seems to be purposeful. This is justifiable, as the large number of varieties collected from all over the world serve mainly as the fundamental material for the evolution of high yielding strains. Further the classification helps to take stock of the variability available in the germplasm with the purpose of utilising them in the breeding programme, while simultaneously trying to strengthen the gene bank with varieties of new combinations of characters from other sources. With this objective, an attempt to classify the varieties available in the germplasm at the Castor Research Station, Salem has been made and the results are presented.

Hybrids of ryegrasses and meadow fescue and their value for grass breeding

1. In attempts to intercross Lolium perenne and L. multiflorum with Festuca pratensis in a glasshouse, 13,284 emasculated flowers of diploid, triploid and tetraploid Lolium plants were provided with pollen of diploid and tetraploid Festuca plants. Only the combinations 2n\sx4n and 3n\sx4n produced hybrids, viz. on average 5.3 and 1.0 mature hybrid plants per 100 pollinated flowers. In crosses performed in winter these averages were 12.0 and 4.9 respectively. 2. Non-emasculated spikes of diploid, triploid and tetraploid plants of L. perenne and L. multiflorum in the field were enclosed in pergamine bags with panicles of diploid, triploid and tetraploid plants of F. pratensis. Apart from the above-mentioned combinations hybrids were also obtained of the crosses 2n\sx2n and 2n\sx3n. The number of hybrids produced per inflorescence was on average nearly as high as in corresponding crosses in the glasshouse. By bagging together spikes of self-incompatible diploid plants of L. perenne and L. multiflorum with panicles of tetraploid plants of F. pratensis in the field, large numbers of triploid hybrid seeds may easily be obtained. This opens the possibility of using seed treatment with colchicine for the production of hexaploids. 3. Triploid hybrids showed a better production in spring and a better aftermath growth in summer than either parent plants. Spontaneously obtained hybrids were more winterhardy than most winterhardy indigenous types of perennial ryegrass. 4. All artificial and most natural hybrids had no dehiscent anthers; the percentage of normal pollen varied in the artificial hybrids from 0 to 3.8%, in the natural hybrids from 0 to 10%. Several plants in both groups were slightly female fertile. Some plants with hybrid characters, collected from natural grassland, had dehiscent anthers and more than 75% stainable pollen; their female fertility was fairly good. 5. Open pollinated seeds of triploid male sterile hybrids produced, apart from a majority of plants closely resembling the parent species, or the F1 hybrids, also types with new combinations of characters. The male fertility was considerably higher than in the previous generation: several plants had dehiscent anthers. In spontaneous families of the male fertile hybrid forms greatly deviating types of Lolium occurred. 6. Some possibilities of the various cross combinations for the breeding of ryegrasses are discussed.