Home About us Contact
|
Home About us Contact | ||
|
|
||
Outgroup Comparison (outgroup + comparison)
Selected AbstractsFemale gametophyte development in Aristolochia labiata Willd. (Aristolochiaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2008ERIC N. MADRID Piperales are an extremely diverse angiosperm lineage in terms of female gametophyte structure and, as such, an excellent candidate for comparative investigations of developmental evolution. In Piperales, Aristolochiaceae are sister to clades in which several divergent patterns of female gametophyte development are prevalent. Outgroup comparisons and explicit analyses of character evolution demonstrate that Polygonum -type female gametophyte development and structure in Aristolochiaceae appears to represent the plesiomorphic condition from which the divergent ontogenies of Piperales evolved. Here, we present detailed analyses of female gametophyte development in Aristolochia labiata that combine light and confocal microscopy with three-dimensional computer reconstruction. Our reconstructions demonstrate that, at the two-nucleate stage of development, separation of nuclei to opposite poles of the female gametophyte does not appear to be dependent on vacuolar expansion as generally hypothesized. We also found a decrease in antipodal volume following formation of the secondary nucleus. Our data provide a baseline for future efforts to describe developmental modifications responsible for evolutionary transitions in female gametophyte ontogeny throughout Piperales. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 19,29. [source] The peristomatic structures of Lithobiomorpha (Myriapoda, Chilopoda): Comparative morphology and phylogenetic significanceJOURNAL OF MORPHOLOGY, Issue 2 2008Markus Koch Abstract A comparative survey of the epipharynx and hypopharynx of lithobiomorph centipedes by light and scanning electron microscopy examines 18 species that sample the major groups of both families, the Lithobiidae and Henicopidae. Cladistic analysis of 11 characters of the peristomatic structures together with 29 additional morphological characters serves as a basis for interpreting the evolution of the lithobiomorph peristomatic structures. Scutigeromorpha is used for outgroup comparison in the framework of a homology scheme for the basic components of the epi- and hypopharynx. Compared to other chilopods, the monophyly of Lithobiomorpha is supported by a row of distinctive bottle-shaped gland openings at the border between the labral and clypeal parts of the epipharynx, as well as by a distinctive shape of the hypopharynx. Paired rows of elongate spines on the clypeal part of the epipharynx are an apomorphic character of Lithobiidae. The transformation of these spine rows into a few groups of branching spines is characteristic for the Monotarsobius group sensu Verhoeff. Similar groups of branching clypeal spines characterize the Anopsobiinae within Henicopidae, whereas Henicopinae possess a dense cluster of short, simple spines instead. The recently described genus Dzhungaria is resolved closer to Henicopinae than to Anopsobiinae, a hypothesis supported by a field of grooves on the medial labral part of the epipharynx. Monophyly of Henicopidae does not receive unique support from the peristomatic structures although two homoplastic characters contribute to this node; among these, the reduction of a median spine field between clypeal and labral parts of the epipharynx to a narrow transverse band also supports a close relationship between the Ezembius group and Hessebius within Lithobiidae. An Ezembius + Hessebius clade is additionally supported by the absence of a transverse bulge between the clypeal and labral parts of the epipharynx, a character otherwise present in all lithobiomorph species studied so far. Lithobius is resolved as polyphyletic, with different species being most closely related to such genera as Australobius, Hessebius and Pleurolithobius. J. Morphol., 2008. © 2007 Wiley-Liss, Inc. [source] Evolution of the spermatozoon in muroid rodentsJOURNAL OF MORPHOLOGY, Issue 3 2005William G. Breed Abstract In the rodent superfamily Muroidea, a model for the evolution of sperm form has been proposed in which it is suggested that a hook-shaped sperm head and long tail evolved from a more simple, nonhooked head and short tail in several different subfamilies. To test this model the shape of the sperm head, with particular emphasis on its apical region, and length of sperm tail were matched to a recent phylogeny based on the nucleotide sequence of several protein-coding nuclear genes from 3 families and 10 subfamilies of muroid rodents. Data from the two other myomorph superfamilies, the Dipodoidea and kangaroo rats in the Geomyoidea, were used for an outgroup comparison. In most species in all 10 muroid subfamilies, apart from in the Murinae, the sperm head has a long rostral hook largely composed of acrosomal material, although its length and cross-sectional shape vary across the various subfamilies. Nevertheless, in a few species of various lineages a very different sperm morphology occurs in which an apical hook is lacking. In the outgroups the three species of dipodid rodents have a sperm head that lacks a hook, whereas in the heteromyids an acrosome-containing apical hook is present. It is concluded that, as the hook-shaped sperm head and long sperm tail occur across the muroid subfamilies, as well as in the heteromyid rodents, it is likely to be the ancestral condition within each of the subfamilies with the various forms of nonhooked sperm heads, that are sometimes associated with short tails, being highly derived states. These findings thus argue against a repeated evolution in various muroid lineages of a complex, hook-shaped sperm head and long sperm tail from a more simple, nonhooked sperm head and short tail. An alternative proposal for the evolution of sperm form within the Muroidea is presented in the light of these data. J. Morphol. © 2005 Wiley- Liss, Inc. [source] Patterns of evolutionary transformation in the petrosal bone and some basicranial features in marsupial mammals, with special reference to didelphidsJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 1 2002M. R. SÁNCHEZ-VILLAGRA Twelve petrosal and four nonpetrosal characters were coded for representatives of all 15 extant genera of Didelphidae and for 16 additional genera of marsupials representing all extant orders. Three basal metatherians were used as outgroup comparison. Histological sections of a subset of the data were examined. An intermediate position of the hiatus Fallopii supports the monophyly of Didelphidae. Several basicranial regions support different clades within the Didelphidae that recent molecular work has identified, including a sister group relationship of Caluromys and Caluromysiops, the monophyly of large opossums, a Lestodelphys-Thylamys clade, and a Lestodelphys-Thylamys-Gracilinanus-Marmosops clade. Glironia lacks petrosal and jaw synapomorphies of Caluromys and Caluromysiops. The transverse canal, a synapomorphy of the crown-group Marsupialia, opens as a single foramen anterior to the carotid foramen in most marsupials or as numerous foramina in the pterygoid fossa in diprotodontians. It is either intramural (most marsupials) or simply endocranial (most diprotodontians excluding koalas and wombats). Loss of a deep sulcus in the anterior pole of the promontorium for the internal carotid artery and a rostral tympanic process of the petrosal also characterize the groundplan of the crown group Marsupialia. Pouch-young wombats show a groove in the anterior pole of the petrosal for the internal carotid artery. The absence of a prootic canal foramen in the tympanic side of the petrosal of adults supports the monophyly of Australidelphia. Some pouch-young marsupials possess a prootic canal that is later lost in ontogeny. A rather flat promontorium and a crest running medio-distally in the middle of the promontorium characterize Macropodidae. Zur Evolution des Petrosum und des Basicranium bei Beuteltiere, unter besonderer Berücksichtigung der Didelphiden Zwolf Merkmale des Petrosum und vier Merkmale des Basicranium wurden bei Vertretern aller Gattungen der Didelphidae sowie bei 16 zusätzlichen Taxa der Marsupialia untersucht. Drei basale Metatheria wurden als Außengruppen verwendet. Histologische Schnittserien von verschiedenen Arten wurden in die Untersuchung einbezogen. Einige monophyletische Gruppen innerhalb der Didelphidae, die durch molekulare Analysen identifiziert wurden, werden durch im Rahmen dieser Arbeit gewonnenen morphologischen Merkmale unterstützt, u. a., das Schwestergruppenverhältnis von Caluromys und Caluromysiops, die Monophylie von großen Opossums, sowie die Monophylie der Taxon-Gruppe Lestodelphys-Thylamys-Gracilinanus-Marmosops sowie der Gruppierung Marmosa-Micoureus-Monodelphis. Glironia fehlt die Synapomorphien von Caluromys und Caluromysiops, die in dieser Arbeit gefunden wurden. Das Fehlen des `deep sulcus' für die Arteria Carotis communis am Vorderende des Petrosum, ein Processus rostralis anterior des Petrosum und der Canalis transvs. werden als Synapomorphie der Kronengruppe Marsupialia gewertet. Das Fehlen des Canalis prooticus bei Cranien von Adultstadien unterstützt das Monophylum Australidelphia. Einige Beuteljunge von Australidelphien besitzen einen Canalis prooticus, der später in der Ontogenese zurückgebildet wird. Die Öffnung des Canalis transvs. liegt bei den meisten Marsupialia rostral zum Foramen caroticum, während bei den Diprotodontia die Öffnung aus verschiedenen Foramina in der Fossa pterygoidea besteht. Der Canalis transvs. ist entweder `intramural' oder einfach endocranial (Diprotodontia, aussschließlich Koalas und Wombats). Beuteljunge Wombat besitzen am Vorderende des Petrosums eine Rinne für die Arteria carotis interna. [source] Evolution of Funnel-Revolver Flowers and Ornithophily in Nasa (Loasaceae)PLANT BIOLOGY, Issue 1 2006M. Weigend Abstract: Floral morphology, distribution, and flower visitors for 60 taxa of Nasa are investigated and compared to molecular trees inferred both from a combined marker analysis (ITS1 and trnLUAA) and from a single marker (ITS1). Flowers conform to two different floral types: Firstly, "tilt-revolver flowers", with spreading to reflexed, white to yellow petals and small, brightly coloured floral scales contrasting with the petals and firmly enclosing the nectar (Saccatae and Carunculatae); secondly, "funnel-revolver flowers", with half-erect to erect, orange to red petals and floral scales not contrasting with the petals, or enclosed in the corolla, and nectar freely accessible by funnel-shaped floral scales (Alatae, Grandiflorae, and N. venezuelensis species group). Phylogenetic analysis shows that "tilt-revolver flowers" represent the plesiomorphic condition by outgroup comparison. The two groups with tilt-revolver flowers in Nasa are not monophyletic (Saccatae are paraphyletic, Carunculatae are polyphyletic). Most Saccatae fall into two monophyletic assemblages, the N. poissoniana species group and the N. triphylla species group. The remainder of Saccatae group either with Grandiflorae (N. insignis species group) or with Alatae (N. laxa species group). The clades retrieved in the molecular analysis contradict the traditional classification, but are congruent with vegetative morphology, details of the flower morphology, and biogeography. "Funnel-revolver flowers" represent the derived condition, but molecular data suggest a convergent development (at least twice independently), since the corresponding species do not constitute a monophyletic group. "Tilt-revolver flowers" are visited and pollinated by bees (especially Colletidae), whereas "funnel-revolver flowers" are mostly visited by hummingbirds. The transition from melittophily to ornithophily may have been the license for the colonization of, and the diversification in, both cloud forest and high Andean habitats. [source] Lateral line system and its innervation in Tetraodontiformes with outgroup comparisons: Descriptions and phylogenetic implicationsJOURNAL OF MORPHOLOGY, Issue 5 2010Masanori Nakae Abstract The lateral line system and its innervation in ten tetraodontiform families and five outgroup taxa were examined. Although some homology issues remained unresolved, tetraodontiforms were characterized by having two types (at least) of superficial neuromasts (defined by the presence or absence of supporting structures) and accessory lateral lines and neuromasts (except Molidae in which "accessory" elements were absent). The preopercular line in Tetraodontiformes was not homologous with that of typical teleosts, because the line was innervated by the opercular ramule that was newly derived from the mandibular ramus, the condition being identical to that in Lophiidae. Within Tetraodontiformes, the number of neuromasts varied between 70 and 277 in the main lines and between 0 and 52 in accessory elements. Variations were also recognized in the presence or absence of the supraorbital commissure, mandibular line, otic line, postotic line, ventral trunk line, and some lateral line nerve rami, most notably the dorsal branch of the opercular ramule, being absent in Aracanidae, Ostraciidae, Tetraodontidae, Diodontidae, and Molidae. Morphological characteristics derived from the lateral line system and its innervation provided some support for a sister relationship of tetraodontiforms with lophiiforms. J. Morphol., 2010. © 2009 Wiley-Liss, Inc. [source] | ||||||||||