Cnidaria

Seven sea anemone species from coral reefs in the southern Gulf of Mexico are taxonomically diagnosed
and images from living specimens including external and internal features, and cnidae are provided. Furthermore,
the known distribution ranges from another 10 species are extended. No species records of sea
anemones have been previously published in the primary scientific literature for coral reefs in the southern
Gulf of Mexico and thus, this study represents the first inventory for the local actiniarian fauna.

Conventional wisdom suggests that bilateral organisms arose from ancestors that were radially, rather than bilaterally, symmetrical and, therefore, had a single body axis and no mesoderm. The two main hypotheses on how this transformation took place consider either a simple organism akin to the planula larva of extant cnidarians or the acoel Platyhelminthes (planuloid-acoeloid theory), or a rather complex organism bearing several or most features of advanced coelomate bilaterians (archicoelomate theory). We report phylogenetic analyses of bilaterian metazoans using quantitative (ribosomal, nuclear and expressed sequence tag sequences) and qualitative (HOX cluster genes and microRNA sets) markers. The phylogenetic trees obtained corroborate the position of acoel and nemertodermatid flatworms as the earliest branching extant members of the Bilateria. Moreover, some acoelomate and pseudocoelomate clades appear as early branching lophotrochozoans and deuterostomes. These results strengt...

RESUMEN. Medusas, sifonóforos y ctenóforos son organismos ecológicamente importantes por su papel como depredadores voraces en la cadena trófica, ya que en altas densidades ocasionan problemas económicos. En las costas mexicanas del Golfo de México existe conocimiento de la riqueza taxonómica de estos animales macrozooplanctonicos, pero aún se desconoce qué especies se encuentran en los arrecifes coralinos del norte de Veracruz. Este estudio presenta los primeros registros de este grupo para el Sistema Arrecifal Lobos-Tuxpan. Se identificaron tres especies de medusas, un sifonóforo y dos especies de ctenóforos a partir de registros fotográficos obtenidos en los arrecifes Tuxpan, Enmedio, Tanhuijo, Oro Verde y Lobos. El taxón Cyanea sp. se registra por pri-mera vez para el suroeste del Golfo de México y Cestum veneris es nuevo registro para el litoral veracruzano. Las especies Aurelia aurita (medusa), Physalia physalis (sifonóforo) y Mnemiopsis leidyi (ctenóforo) se observaron en la mayoría de los arrecifes estudiados. La información aquí presentada puede ser útil para el sector turístico al evitar las medusas y sifonóforos que son tóxicos. ABSTRACT. Jellyfish, siphonophores and ctenophores are ecologically important organisms due to their role as voracious predators in the trophic chain, which in high densities may cause economic problems. There is knowledge of the taxonomic wealth of these macrozooplanktonic animals in the Mexican coasts of the Gulf of Mexico, but it is still unknown what species are found in the coral reefs from the north of Veracruz. This study presents the first records of this group for the Lobos-Tuxpan Reef System. Three species of jellyfish, one siphonophore and two ctenophores, were identified through photographic records belonging to the Tuxpan, Enmedio, Tanhuijo, Oro Verde and Lobos reefs. For the first time, the species Cyanea sp. for the SouthWest of the Gulf of Mexico and Cestum veneris for the Veracruz coast are recorded. The species Aurelia aurita (jellyfish), Physalia physalis (siphonophore) and Mnemiopsis leidyi (ctenephore) were observed in most of the studied reefs. The information provided here may be useful in the tourist sector to avoid toxic jellyfish and siphonophores.

Many supraspecific zoantharian names have long and complicated histories. The present list is provided to advise researchers on the current state of supraspecific nomenclature of the zoantharians, particularly given the recent attention paid to the taxonomy, phylogeny, and biodiversity of this order. At the same time, several taxonomic issues brought to light by recent research are resolved. Details on the taxonomic and nomenclatural history of most groups are provided, along with appendices of invalid supraspecific names.

Hydrozoan cnidarians are widespread in modern
environments, but their polyps or hydroids, when not
biomineralized, are generally rare in the fossil record. To
assess the affinities of four hydrozoan taxa previously
described on the basis of supposed fossils of non-biomineralized
hydroids, we re-analysed the type specimens of these
taxa using a combination of light and electron microscopic
tools, including backscattered electron (BSE) scanning electron
microscopy (SEM) and energy-dispersive X-ray spectroscopy
(EDS). New morphological, ultrastructural and
taphonomic data were generated for Archaeoantennularia
byersi from the Devonian of Michigan, Archaeocryptolaria
compacta from the Ordovician of Virginia, and Mazohydra
megabertha and Drevotella proteana from the Carboniferous
Mazon Creek Lagerst€atte of Illinois, which are preserved as
carbonaceous fossils, aluminosilicate films and iron carbonate
minerals in siderite concretions, respectively. In the context
of these results, we provide a review of the fossil record
of non-biomineralized hydroids, describe possible biases and
changes through time in their occurrence and preservation,
and evaluate the criteria commonly used to identify and
interpret their fossils. Although hydroids have been reported
from Phanerozoic (particularly lower Palaeozoic) rocks
around the world, many putative hydroids from the Palaeozoic
are poorly substantiated and may actually be hemichordates.
Indeed, none of the type specimens in this study
represent unequivocal hydrozoans. As shown in BSE images,
metatype specimens of A. byersi possess autothecae, fusellae,
stolons, stolothecae and bithecae, which decisively indicate
that they are dendroid graptolites rather than hydroids. The
analyses yielded no evidence that A. compacta, Mazohydra
and Drevotella are hydrozoans, as their holotypes lack the
diagnostic morphological, taphonomic and ecological features
characteristic of purported hydroid analogues. Consequently,
our results suggest that many Palaeozoic hydroids
may be hemichordates and that interpretations of hydroid
fossils should be tested and refined using data collected via
in situ analytical techniques like BSE-SEM and EDS.

Corals provide the foundation of important tropical reef ecosystems but are in global decline for multiple reasons, including climate change. Coral health depends on a fragile partnership with intracellular dinoflagellate symbionts. We argue here that progress in understanding coral biology requires intensive study of the cellular processes underlying this symbiosis. Such study will inform us on how the coral symbiosis will be affected by climate change, mechanisms driving coral bleaching and disease, and the coevolution of this symbiosis in the context of other host-microbe interactions. Drawing lessons from the broader history of molecular and cell biology and the study of other host-microbe interactions, we argue that a model-systems approach is essential for making effective progress in understanding coral cell biology.

We have firstly investigated the toxicological activity by hemolytic assay of crude extract obtained by sonication of holotrichous isorhiza isolated nematocysts of the Scyphozoan Pelagia noctiluca, collected in the Strait of Messina. The hemolytic activity was both time-and dose-dependent on fish, rabbit, chicken and human red blood cells. At lowest doses rabbit and chicken erythrocytes were the most sensitive, whereas those of eel were the most resistant to the crude extract. Different storage conditions, such as -20 °C, -80 °C for up to 6 months and lyophilization, did not affect the stability of crude venom. Moreover, neither treatment at 4 °C, 20 °C and 37 °C for different time periods ranging between 30 min and 24 h, nor harsh thermal treatment at 80 °C and 100 °C affected the hemolytic power. The crude venom resulted even stable towards proteolysis and alkaline pH values.