Biomedical subjects

J Mariaux

Publications and source records attributed to J Mariaux.

4 recordsLinked to original sources

PubMed1996

A molecular phylogenetic survey of the nightjars and allies (Caprimulgiformes) with special emphasis on the potoos (Nyctibiidae).

A 656-pb fragment of the mitochondrial cytochrome b gene was sequenced for six species of Central and South American potoos (genus Nyctibius, Nyctibiidae) as well as for selected representatives of all other caprimulgiform families. Sequence divergence among potoos was much higher (11.1-16.2%) than has typically been observed among congeneric species of birds, suggesting that the species of Nyctibius are quite old. Divergence among families was also quite high (13.7-21.8%), confirming recent DNA-DNA hybridization studies. Such high genetic divergences in a functionally constrained gene like cyt b indicate that many of those sites which are free to vary will have experienced multiple substitutions. We therefore performed phylogenetic analysis using parsimony under a variety of weighting schemes intended to reduce the effect of multiple substitutions. The monophyly of all the traditional caprimulgiform families was confirmed and a number of new hypotheses of relationship emerged. From our analysis, it appears that the oilbird (Steatornis) is an ancient member of the order, and it is not closely related to the potoos. We also note the close link between Aegothelidae and Caprimulgidae, and the basal position of the Podargidae/Batrachostomidae clade in the phylogeny. These results are in accordance with several classical works of the first half of the century. The relationships of the various Nyctibius species to each other have not been fully resolved; however, a close link between N. leucopterus and N. maculosus appears to be highly probable from our data.

Amino Acid Sequence↗

PubMed1996

Cestode systematics: any progress?

In this short review, I summarize the recent advances, the present state and future for research in the field of cestode systematics. First, within an historical context, I briefly outline why our understanding of relationships within the Eucestoda has been problematic and contentious. On this foundation, I then summarize and discuss recent progress at various supraspecific levels, and at the specific level. Of particular interest in this respect is the discrepancy between the methods applied to understand the evolution of a few well-studied taxa, for instance the complex of Echinococcus species, contrasted with our relative ignorance about the systematic status of the vast majority of species. This leads to a review of the diversity of classical and new methodologies currently applied in the field of cestode systematics. Applications of morphoanatomical investigations as well as more recent molecular tools are examined, and some less common approaches are also reviewed. Finally, several practical and theoretical difficulties that are specific to the domain are discussed. These include problems in accessibility of material and adequate consideration of host-specificity. Our current state of knowledge represents an apparent paradox in that significant progress has indeed been achieved during the last 15 years, but appears limited to very specific cases, principally among medically important taxa. Conversely, more general works whose utility has been long recognized have not been addressed despite their conceptual simplicity. Consequently the development of new techniques, especially molecular ones, to allow access to new classes of characters is encouraged. However the need for continuous effort using more traditional approaches, including continued field collection, excellent and detailed descriptions and redescriptions, as well as critical revisions of classical monographs is also emphasized. A synergism linking morphological and molecular characters and phylogenetic approaches to analysis provides a firm foundation for rapid and seminal advances in the elucidation of relationships among the Eucestoda.

Animals↗

PubMed1992

A new genus of Metadilepididae (Cestoda: Cyclophyllidea) parasitic in Terpsiphone rufiventer (Aves: Muscicapidae) from the Ivory Coast.

Pseudadelphoscolex eburnensis, a new genus and species of metadilepidid Cyclophyllidea parasitic in the red-bellied paradise flycatcher, Terpsiphone rufiventer, from the Ivory Coast, is described. The new species is characterized by davaineidlike rostellar hooks, absence of a rostellar pouch, a huge cirrus pouch in gravid proglottids, a bilobed uterus that becomes progressively reticular, absence of a paruterine organ, and eggs with an internal coat forming a crescentic protuberance outside the embryophore. The presence of a single row of rostellar hooks together with the lack of spines on the sucker and the structure and position of the uterus exclude this new material from Davaineidae. It cannot be placed in Dilepididae due to the lack of a rostellar pouch or in Paruterinidae because of the lack of a paruterine organ. The position of the excretory ducts in relation to the genital pores and the alternance of these pores are the main characters used to exclude this new species from the known genera of Metadilepididae. The diversity of forms of Metadilepididae in intertropical terrestrial birds is increased, and the validity of this taxon is strengthened.

Animals↗

PubMed1990

A new genus of Dilepididae (Cestoda) of the yellowbill Ceuthmochares aereus (Cuculidae) from the Ivory Coast.

Bonaia africana n. gen., n. sp. (Cestoda: Dilepididae) has been found in Ceuthmochares aereus (Aves: Cuculidae) in the Ivory Coast (West Africa). This new tapeworm is mainly characterized by its unusual rostellar hooks that are implanted irregularly and which present a variable form and length in the same rostellum. The differential diagnosis, particularly in comparison with the closely related genera Liga and Amoebotaenia, is presented: Liga possesses an atrial bundle of setae and Amoebotaenia 1 row of well built hooks with a typical blade. It is assumed that the unusual disposition of the rostellar hooks described here could be a transitional form between the 1- and 2-row patterns or a degenerate derivative of a regular arrangement.

Animals↗