28 research outputs found
THE INFLUENCE OF TIDAL AND RAINFALL CYCLES ON INTERTIDAL NEMATODES: A CASE STUDY IN A TROPICAL SANDY BEACH
Is nematode colonisation in the presence of Scolelepis in tropical sandy-beach sediment similar to the colonisation process in temperate sandy beaches?
Nematodes as indicators of shrimp farm impact on an amazonian estuary (Curuçá, Pará, Brazil)
Tantulocarida (Crustacea: Maxillopoda) : a new taxon from the temporary meiobenthos
Two new genera of Tantulocarida are described from the Ligurian deep sea (Western Mediterranean) off Corsica. Xenalytus scotophilus is referred to the Microdajidae and differs from Microdajus GREEVE in thoracopodal segementation as well as in the presence of coupling spines on thoracopod 6 and longitudinal lamellae on the cephalic shield. Aphotocentor styx is placed in the Deoterthridae and holds an intermediate position between Deoterthron BRADFORD & HEWITT and Boreotantulus HUYS & BOXSHALL. Some aspects of cephalon internal structure are described for the first time and give a possible explanation for the mechanism of stylet protrusion. The external structures of the oral disc are described using SEM. The discovery of well-developed muscles in the trunk and thoracopods is discussed in the light of the benthic phase the tantulus passes through. The boundary between the thorax and abdomen in the tantulus is reinterpreted, corroborating the 5-7-5 bodyplan of the hypothetical urmaxillopodan as found in the Upper Cambrian Skaracarida and possibly also Dala peilertae MULLER. Some aspects related to dispersal, infection, and feeding are reinterpreted or approached from a different perspective. SEM of Microdajus langi GREVE gives evidence that the tantuli hatch via a conspicuous slit located at the posterior end of the female trunk sac. A worldwide key to the tantulocaridan families and genera is given, and distributional records are compiled. It is suggested that Tantulocarida might be common representatives of the temporary meiobenthos and that their present species number represents only the tip of the iceberg