1,721,065 research outputs found
The cnidome of Olindias muelleri (Cnidaria: Hydrozoa: Limnomedusae) from South Adriatic Sea
No full textOlindias muelleri is a hydromedusa distributed in the Mediterranean Sea and tropical Atlantic Ocean. Although this species is frequently reported in the Mediterranean Sea and its sting can cause serious human health problems, no data are currently available on its nematocysts. Therefore, the aim of the present investigation is to provide the description of its cnidome. Three types of nematocysts (microbasic b-mastigophores, pseudostenoteles and microbasic euryteles) and two unidentified types were identified in O. muelleri hydromedusa. For each nematocysts type, the location and abundance were recorded from tentacles, bell margin and manubrium. The three types of nematocysts identified in O. muelleri match with the types observed in the Brazilian Olindias sambaquiensis, the only species of the same genus for which information about the cnidome is available. However, the two species are clearly distinguished in terms of nematocyst size and location. No nematocysts have been observed in the exumbrella and subumbrella of O. muelleri, indicating that only its tentacles, bell margin or manubrium are responsible of envenomation, while the contact with all structures of O. sambaquiensis could be stinging. In addition, the unidentified medium-size capsules represent a character exclusive of O. muelleri
Eudendrium (Cnidaria, Anthomedusae) from the Antarctic Ocean with a description of new species.
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First evidence of a specific association between a stylasterid coral and a boring cyanobacterium
No full textCarbonate factory of Pietra di Finale coastal wedge (Miocene). The unusual abundance of stylasterids (Cnidaria, Hydrozoa)
Full text linkThis work focuses on the carbonate factories constituting the Pietra di Finale Fm cropping out in the Ligurian Alps. This unit
constituted a mixed carbonate–siliciclastic coastal wedge developed during the Middle Miocene. The carbonate factories
characterizing the coastal wedge of the Pietra di Finale clearly differ from those of the coastal mixed systems and carbonate
platforms developing during the Miocene elsewhere in the Mediterranean area. Here, in the Ligurian Alps, the euphotic
carbonate factory does not show any evidence of seagrass meadows and coral bioconstructions. Zooxanthellate corals are
present only as skeletal debris associated with abundant stylasterids. In the mesophotic and oligophotic zones, the typical
oligophotic biota of red algae and larger benthic foraminifers are strongly reduced. The coastal wedge of the Pietra di Finale
shows an unusual abundance of stylasterids, classically interpreted as deep-water biota. However, in this example, the absence
of low-energy textures and other skeletal components suggest a shallow-water origin, probably in the eu- or mesophotic
zone. The stylasterids colonized the hard substrates available and were successively removed and resedimented to form the
skeletal fraction of the coastal wedge of the Pietra di Finale. The abundance of stylasterids is restricted to particular and
limited situations in the Miocene of the Mediterranean, thus suggesting that their abnormal development is controlled by
local rather than global factors
Macrorhynchia species (Cnidaria: Hydrozoa) from the Bunaken National Marine Park (North Sulawesi, Indonesia) with a description of two new species
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