Hydroides

Abstract: Solanum hydroides Gouvea & Giacomin, sp. nov., is described from central Brazilian Atlantic Forest. It is known from only three localities in Espirito Santo and Minas Gerais states, where granitic/gneissic outcrops (inselbergs or sugar loaves) are ubiquitous. The new species, here described, belongs to Solanum subgenus Leptostemonum (or the Leptostemonum clade; i.e. the spiny solanums) and is morphologically related to S. hexandrum Vell. and S. sublentum Hiern, with which it shares the shrubby habit, decurrent leaf bases and well-developed calyces that become accrescent, covering glabrous fruits. Solanum hydroides is unique in its combination of comparatively more delicate habit, indumentum of exclusively stellate eglandular trichomes, accrescent but never inflated fruiting calyces that only partially cover the fruits and comparatively shortly lobed and strictly white corollas. The species is threatened with extinction and assessed as Vulnerable (VU), based on the IUCN criteria.

Abstract: The faunistic analysis of benthic samples taken from 0 to 200 m depths on the eastern Levantine coast of Turkey in September 2005 yielded the presence of 16 serpulid species, 9 of which are considered to be aliens: Hydroides brachyacanthus, H. diramphus, H. elegans, H. heterocerus, H. homoceros, H. minax, H. operculatus, Pomatoleios kraussii and Spirobranchus tetraceros. Ten species are new records for the Levantine coast of Turkey. Hydroides operculatus and P. kraussii formed dense populations on shallowwater artificial and natural hard substrates in the area. The population density and biomass (wet weight) of H. operculatus reached up to 384,000 individuals.m -2 and 245.76 g.m -2 in Mersin Bay and those of P. kraussii up to 52,000 individuals.m -2 and 154.76 g.m -2 in Iskenderun Harbour. The species with the highest frequency values at shallow water stations (0-5 m) were P. kraussii (50%), Pomatoceros lamarckii (50%), H. minax (42%), H. brachyacanthus (38%) and H. elegans (29%). Alien species were not found at depths deeper than 25 m. Alien species accounted for more than 85% of the serpulid specimens collected. Brief descriptions of the species, and their distributional, reproductive and ecological characteristics are given. In addition, population characteristics of the dominant species, H. operculatus and P. kraussii, are analyzed.

Abstract: Diverse animal taxa metamorphose between larval and juvenile phases in response to bacteria. Although bacteria-induced metamorphosis is widespread among metazoans, little is known about the molecular changes that occur in the animal upon stimulation by bacteria. Larvae of the tubeworm Hydroides elegans metamorphose in response to surface-bound Pseudoalteromonas luteoviolacea bacteria, producing ordered arrays of phage tail-like metamorphosis-associated contractile structures (MACs). Sequencing the Hydroides genome and transcripts during five developmental stages revealed that MACs induce the regulation of groups of genes important for tissue remodeling, innate immunity, and mitogen-activated protein kinase (MAPK) signaling. Using two MAC mutations that block P. luteoviolacea from inducing settlement or metamorphosis and three MAPK inhibitors, we established a sequence of bacteria-induced metamorphic events: MACs induce larval settlement; then, particular properties of MACs encoded by a specific locus in P. luteoviolacea initiate cilia loss and activate metamorphosis-associated transcription; finally, signaling through p38 and c-Jun N-terminal kinase (JNK) MAPK pathways alters gene expression and leads to morphological changes upon initiation of metamorphosis. Our results reveal that the intricate interaction between Hydroides and P. luteoviolacea can be dissected using genomic, genetic, and pharmacological tools. Hydroides' dependency on bacteria for metamorphosis highlights the importance of external stimuli to orchestrate animal development. The conservation of Hydroides genome content with distantly related deuterostomes (urchins, sea squirts, and humans) suggests that mechanisms of bacteria-induced metamorphosis in Hydroides may have conserved features in diverse animals. As a major biofouling agent, insight into the triggers of Hydroides metamorphosis might lead to practical strategies for fouling control.

Abstract: A taxonomic revision of the Hydroides species (Polychaeta: Serpulidae) from the Western Atlantic Region is presented. Twenty-six taxa are described, including a comparison between four species with ‘winged’ verticil spines: Hydroides alatalateralis, H. elegantulus, H. floridanus and H. spongicola, between two forms of the H. mongeslopezi complex, and between two forms of the H. brachyacanthus complex. Three widespread species are recorded: H. dianthus, H. diramphus and H. elegans. Five new forms are recorded, including one with 7-9 thoracic chaetigers. Three species are newly described: H. lambecki n. sp., H. similoides n. sp. and H. salazarvallejoi n. sp. Seven specific names are placed into synonymy: H. abbreviatus Kroyer [in] Morch, H. benzoni Morch, H. decorus Treadwell, H. dianthoides Augener, H. dunkeri Morch, H. hexagonus Bosc and H. serratus Bush. A glossary, standard terminology and a key to all species from the Western Atlantic region are given.