The dinoflagellate family Symbiodiniaceae comprises numerous genera and species with large differences in diversity, ecology, and geographic distribution. An evolutionarily divergent lineage common in temperate symbiotic cnidarians and designated in the literature by several informal names including "temperate-A", AI, Phylotype A´ (A-prime), and "Mediterranean A", is here assigned to the genus Philozoon. This genus was proposed by Geddes (1882) in one of the earliest papers that recognized "yellow cells" as distinct biological entities separate from their animal and protist hosts. Using phylogenetic data from nuclear (rDNA), chloroplast (cp23S) and mitochondrial genes (cob and cox1), as well as morphology (cell size), ecological traits (host affinity) and geographic distributions, we emend the genus Philozoon Geddes and two of its species, P. medusarum and P. actiniarum, and describe six new species. Each symbiont species exhibits high host fidelity for particular species of sea anemone, soft coral, stony coral, and a rhizostome jellyfish. Philozoon is most closely related to Symbiodinium (formerly Clade A), but, unlike its tropical counterpart, occurs in hosts in shallow temperate marine habitats from Northern and Southern Hemispheres including the Mediterranean Sea, northeastern Atlantic Ocean, eastern Australia, New Zealand and Chile. The existence of a species-diverse lineage adapted to cnidarian hosts living in high latitude habitats with inherently wide fluctuations in temperature calls further attention to the ecological and biogeographic reach of the Symbiodiniaceae.
ABSTRACT. Many of the characteristics used in sea anemone taxonomy can only be examined through histological sections. Since there is no standardized procedure for this purpose, various anesthesia and fixation techniques applied to specimens of the intertidal species Anthopleura hermaphroditica and Bunodactis hermafroditica are discussed. Additionally, further modifications are proposed to the Masson's trichrome method according to the results obtained on these species. The combined effect of the short application of menthol crystals, together with small doses of MgCl 2 were the most satisfactory anesthetics for maintaining the specimens expanded. The best preparations were obtained from samples fixed for several months in 8% seawater formalin; however, in order to achieve a good differentiation of the tissue, mordanting the samples with Bouin's fixative was necessary. Besides being a fast method, the modified Masson's trichrome gives very good contrasts between the epithelia and the mesoglea, and allows controlling the timing of differentiation during staining. The present paper includes suggestions and precautions and thus offers practical help for the histological study of sea anemones.
Early View (EV): 1-EV that show large distributional changes over time (Jablonski et al. 2006, Roy andGoldberg 2007). In marine bivalves, for instance, more than half of the genera that originated in the tropics have extend their geographic range towards higher latitudes, evidence used by Jablonski et al. (2006) to suggest an ' out of the tropics ' (OTT) dynamic. Linking evolutionary and ecological processes through a spatially explicit approach, this model pose that ' taxa preferentially originate in the tropics and expand toward the poles but without losing their tropical presence ' . Although the OTT model was tested in marine organisms, phylogenetic information on terrestrial clades also confi rmed these predictions over the tropical conservatism hypothesis (Jansson et al. 2013). In fact, dynamic model simulations of range shifts and diversifi cation processes have shown that extratropical regions may act not only as a macroevolutionary sink but as a dispersal source as well (Goldberg et al. 2005, Arita and V á zquez-Dom í nguez 2008). Either way, results consistently indicate that speciation and extinction cannot fully explain the canonical LDG, thus it seems quite likely that historical dispersion plays a central role in the current distribution of taxa (Goldberg et al. 2005, Jablonski et al. 2006, Roy and Goldberg 2007, Arita and V á zquezDom í nguez 2008, Escarguel et al. 2008, Soria-Carrasco and Castresana 2012.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.