Comparative sperm ultrastructure in five genera of the nudibranch family Chromodorididae (Gastropoda : Opisthobranchia)

Sperm ultrastructure is examined in representatives of five genera of the nudibranch gastropod family Chromodorididae: (Chromodoris, Hypselodoris, Glossodoris, Risbecia and Pectenodoris) and the results compared with previous work on other gastropods, especially other nudibranchs. As chromodoridid phylogeny is still incompletely understood, this study partly focuses on the search for new and as yet untapped sources of informative characters. Like spermatozoa of most other heterobranch gastropods, those of the Chromodorididae are elongate, complex cells composed of an acrosomal complex (small, rounded acrosomal vesicle, and columnar acrosomal pedestal), a condensed nucleus, sub-nuclear ring, a highly modified mid-piece (axoneme + coarse fibres surrounded by a glycogen-containing, helically-coiled mitochondrial derivative) and terminally a glycogen piece (or homologue thereof). The finely striated acrosomal pedestal is a synapomorphy of all genera examined here, but interestingly also occurs in at least one dorid (Rostanga arbutus). Substantial and potentially taxonomically informative differences were also observed between genera in the morphology of the nucleus, the neck region of the mid-piece, and also the terminal glycogen piece. The subnuclear ring is shown for the first time to be a segmented, rather than a continuous structure; similarly, the annular complex is shown to consist of two structures, the annulus proper and the herein-termed annular accessory body.

Is Cadinella ornatissima a chomodorid? Sperm ultra structure in an enigmatic nudibranch (Opisthobranchia Mollusca)

Sperm ultrastructure is described for the nudibranch gastropod Cadlinella ornatissima, type species of the genus Cadlinella (Thiele). Although C. ornatissima exhibits most of the sperm features characteristic of other Opisthobranchia and the Pulmonata (a small, rounded acrosomal vesicle, a complex, helical, mitochondrial derivative - partially paracrystalline, coarse fibres associated with the axoneme), it also possesses a number of previously undescribed and possibly unique features (a longitudinally inrolled acrosomal pedestal, an axial structure within the cavity of the acrosomal pedestal, an electron-dense collar at the anterior region of the acrosomal pedestal, the presence of crystalloid bodies within the glycogen helices of the mitochondrial derivative). To our knowledge this is the first report of crystalloid bodies in mature sperm of any mollusc. Collectively this evidence raises questions concerning the affinities and systematic position of Cadlinella within the Nudibranchia. The peculiar nature of the sperm differences, in comparison with other investigated nudibranchs, suggest that Cadlinella is not easily linked to either the Cadlinidae or Chromodorididae, and should be considered incertae sedis.

Comparative sperm ultrastructure of the Baikalian endemic prosobranch gastropods

Mature euspermatozoan ultrastructure is described for seven species of the rissooidean family Baicaliidae (endemic to Lake Baikal, Russia)-Liobaicalia stiedae, Teratobaikalia ciliata, T. macrostoma, Baicalia carinata, Pseudobaikalia pulla, Maackia bythiniopsis, M. variesculpta, and M. herderiana. For comparison with these species and previously investigated Rissooidea, two species of the Lake Baikal endemic genus Benedictia (B. cf. fragilis and B. baicalensis; Hydrobiidae: Benedictiinae of some authors, Benedictiidae of other authors) in addition to Lithoglyphus naticoides (Hydrobiidae: Lithoglyphinae) and Bythinella austriaca (Hydrobiidae: Bythinellinae) were also investigated. Paraspermatozoa were not observed in any of the species examined, supporting the view that these cells are probably absent in the Rissooidea. In general, the euspermatozoa of all species examined resemble those of many other caenogastropods (basally invaginated acrosomal vesicle, mid-piece with 7-13 helical mitochondria, an annulus, glycogen piece with nine peri-axonemal tracts of granules). However, the presence of a completely flattened acrosomal vesicle and a specialized peri-axonemal membranous sheath (a scroll-like arrangement of 4-6 double membranes) at the termination of the mid-piece, clearly indicates a close relationship between the Baicaliidae and other rissooidean families possessing these features (Bithyniidae, Hydrobiidae, Pyrgulidae, and Stenothyridae). Euspermatozoa of Benedictia, Lithoglyphus, Bythinella, and Pyrgula all have a solid nucleus, which exhibits a short, posterior invagination (housing the centriolar complex and proximal portion of the axoneme). Among the Rissooidea, this form of nucleus is known to occur in the Bithyniidae, Hydrobiidae, Truncatellidae, Pyrgulidae, Iravadiidae, Pomatiopsidae, and Stenothyridae. In contrast, the euspermatozoa of the Baicaliidae all have a long, tubular nucleus, housing not only the centriolar derivative, but also a substantial portion of the axoneme. Among the Rissooidea, a tubular nuclear morphology has previously been seen in the Rissoidae, which could support the view, based on anatomical grounds, that the Baicaliidae may have arisen from a different ancestral source than the Hydrobiidae. However, the two styles of nuclear morphology (short, solid versus long, tubular) occur widely within the Caenogastropoda, and sometimes both within a single family, thereby reducing the phylogenetic importance of nuclear differences within the Rissooidea. More significantly, the occurrence of the highly unusual membranous sheath within the mid-piece region in the Baicaliidae appears to tie this family firmly to the Bithyniidae + Hydrobiidae + Stenothyridae + Pyrgulidae assemblage. Eusperm features of Benedictia spp. strongly resemble those of hydrobiids and bithyniids, and neither support recognition of a distinct family Benedictiidae (at best this is a subfamily of Hydrobiidae) nor any close connection with the hydrobiid subfamily Lithoglyphinae.

Cauda epididymal spermatozoa of the rufous hare wallaby, Lagorchestes hirsutus (Metatheria, Mammalia) imaged by electron and confocal microscopy

The ultrastructure of mature Lagorchestes hirsutus spermatozoa is described for the first time, revealing unusual aspects of sperm structure in macropodid species. The sperm head is ovoid rather than cuneiform, lacks a ventral nuclear groove and has an acrosomal distribution over approximately 85-90% of its dorsal surface. Immediately adjacent to the nuclear membrane the peripheral nucleoplasm in most spermatozoa form an irregular series of distinctive evaginations previously not described in the spermatozoa of any other marsupial. The midpiece is extremely thickened and short, containing no helical network or peripheral plasma membrane specializations. Axonemal structure is unspecialized with no connecting lamellae; dense outer fibres are closely adherent to axonemal doublets. The sperm morphology of this species is highly aberrant in comparison to other macropod taxa and supports the retention of Lagorchestes as a distinctive genus. In light of this new information, skeletal and serological data should be re-evaluated to determine the true taxonomic and phylogenetic position of this species.

Taxonomy of Apenesia Westwood (Hymenoptera, Bethylidae) from Paraná, Brazil

Apenesia quadrimera sp. n., A. rotunda sp. n. and A. clypeata sp. n. are described and illustrated. New geographic records and variation data of A. cusco Evans, 1966, A distinta Corrêa & Azevedo, 2001, A. funebris Evans, 1963, A. fusilis Corrêa & Azevedo, 2001, A. inca Evans, 1963 and A. transversa Evans, 1963 are added.

Taxonomy of Apenesia (Hymenoptera, Bethylidae) from Estação Biológica de Santa Lúcia, Espírito Santo, Brazil

Apenesia aurita sp. nov., from southeastern Brazil, is described and illustrated. Apenesia angusticeps Evans, 1963, A. tenebrosa Evans, 1963, A. pallidicornis Evans, 1963, A. quadrimera Leal & Azevedo, 2001 and A. crenulata Kieffer, 1910 are recorded for the first time to the State of Espírito Santo.

Taxonomy of Epyris (Hymenoptera, Bethylidae) from Paraná, Brazil

Epyris rotundus sp. nov. and Epyris cochlear sp. nov., from southern Brazil, are described and illustrated. Epyris longus Corrêa & Azevedo, 2002, E. argentinicus Evans, 1969, E. angustatus Evans, 1969, E. perpolitus Evans, 1969, E. parallelus Evans, 1969, E. distinctus Corrêa & Azevedo, 2002, E. variatus Corrêa & Azevedo, 2002, E. jugatus Evans, 1969, E. intermedius Evans, 1969 and E. depressigaster Evans, 1966 are recorded for the first time to Paraná, Brazil.

A contribution to a virtual enterprise taxonomy

This paper presents a taxonomy able to contribute to building a framework within the domain of Virtual Enterprises (VE). A VE taxonomy currently does not exist, and this lack is felt in the ambiguous way that some concepts are addressed, leading to a fragment understanding that hinders the development of the science of VE integration and management. The structure of the taxonomy developed is based on the view of the system as a 5-tuple consisting of Input, Control, Output, Mechanism, and Process, which is the underlying system-view in the well-know IDEF0 diagramming technique. In particular, this taxonomy addresses the VE extended lifecycle that implies the use of a meta-organization called Market of Resources, as an original contribution to the VE theory and practice. The taxonomy presented is constructed in a way to be easily complemented with other VE partial taxonomies that may be found in literature.

A taxonomy for virtual enterprises

The purpose of this paper is to present a taxonomy able to contribute to building a framework within the domain of Virtual Enterprises (VE), to facilitate the sharing of knowledge and contributions to knowledge, as well as for trust building among VE stakeholders. A VE taxonomy currently does not exist, and this lack is felt in the ambiguous way that some concepts are addressed, leading to a fragment understanding that hinders the development of the science of VE integration and management. The structure of the taxonomy developed is based on the view of the system as a 5-tuple consisting of Input, Control, Output, Mechanism, and Process, which is the underlying system-view in the well-know IDEF0 diagramming technique. In particular, this taxonomy addresses the VE extended lifecycle that implies the use of a meta-organization called Market of Resources, as an original contribution to the VE theory and practice. The taxonomy presented does not repeat what the literature already includes, or the commonplaces, and it is constructed in a way to be easily complemented with other VE partial taxonomies that may be found in literature. Some suggestions for extensions to other interrelated domains (as evolution leaves taxonomies in an open or incompleteness state) are given in the text.

Knowledge cities: a taxonomy for analyzing software and information service clusters

Software and information services (SIS) have become a field of increasing opportunities for international trade due to the worldwide diffusion of a combination of technological and organizational innovations. In several regions, the software industry is organized in clusters, usually referred to as "knowledge cities" because of the growing importance of knowledge-intensive services in their economy. This paper has two primary objectives. First, it raises three major questions related to the attractiveness of different cities in Argentina and Brazil for hosting software companies and to their impact on local development. Second, a new taxonomy is proposed for grouping clusters according to their dominant business segment, ownership pattern and scope of operations. The purpose of this taxonomy is to encourage further studies and provide an exploratory analytical tool for analyzing software clusters.

The presence of the sperm whale (Physeter macrocephalus) around the Azores: a study of re-sightings from 2003-2012

27th Annual Conference of the European Cetacean Society. Setúbal, Portugal, 8-10 April 2013.

Analysis of residence patterns of Sperm whales (Physeter macrocephalus) in Azores Islands using opportunistic data

27th Annual Conference of the European Cetacean Society. Setúbal, Portugal, 8-10 April 2013.

Behavioural ecology of the sperm whale (Physeter macrocephalus in the North Atlantic Ocean

Tese de Doutoramento em Ciências do Mar, especialidade em Ecologia Marinha.