An updated checklist of ctenophores (Ctenophora: Nuda and Tentaculata) of Mexican seas

Ctenophores are one of the most conspicuous and frequent groups of the gelatinous zooplankton community, but their regional diversity in tropical and subtropical latitudes remains largely unknown. We provide an overview and update of the current knowledge of the diversity in Mexican seas, including ocean and coastal-neritic environments of the Gulf of Mexico, the Mexican Caribbean Sea, and the Mexican Pacific Ocean. Ctenophore records were reviewed based on the available scientific and gray literature, the Naturalista network (www.naturalista.mx), and the ctenophore species collected in the Gulf of California by the Monterey Bay Aquarium Research Institute. A total of 33 taxa (Class Nuda and Tentaculata) were found to occur in Mexican seas, of which 12 of the 33 taxa (36.4 % of the total) were recorded in the Gulf of Mexico, 7 (21.2 %) in the Mexican Caribbean Sea, 25 (75.8 %) in the Gulf of California, 11 (33.3 %) in the Eastern Tropical Pacific, and only 1 (3.0 %) are known in the Northeastern Pacific. Up to nine taxa included in our account represent first records for Mexico (i.e., Bathocyroe fosteri, Kiyohimea usagi, Lampocteis cruentiventer, Leucothea sp., Aulacoctena sp., Haeckelia beehleri, Charistephane fugiens, Bathyctena chuni, and Hormiphora californensis). Due to the lack of data on benthic ctenophores and the sparse studies on oceanic and deep-living species, it is expected that the list will grow as new surveys are performed in the deep sea. The lack of long-term studies on Mexican ctenophores have limited our capacity to draw valid conclusions on their abundance, total diversity, endemicity, and trophic ecology in Mexico.Fil: Puente Tapia, Francisco Alejandro. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gasca Serrano, Rebeca Adriana. El Colegio de la Frontera del Sur; MéxicoFil: Schiariti, Agustin. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Haddock, S.H.D.. Monterey Bay Aquarium Research Institute ; Estados Unido

Bioluminescence Intensity Modeling and Sampling Strategy Optimization

The focus of this paper is on the development of methodology for short-term (1-3 days) oceanic bioluminescence (BL) predictions and the optimization of spatial and temporal bioluminescence sampling strategies. The approach is based on predictions of bioluminescence with an advection-diffusion-reaction (tracer) model with velocities and diffusivities from a circulation model. In previous research, it was shown that short-term changes in some of the salient features in coastal bioluminescence can be explained and predicted by using this approach. At the same time, it was demonstrated that optimization of bioluminescence sampling prior to the forecast is critical for successful short-term BL predictions with the tracer model. In the present paper, the adjoint to the tracer model is used to study the sensitivity of the modeled bioluminescence distributions to the sampling strategies for BL. The locations and times of bioluminescence sampling prior to the forecast are determined by using the adjoint-based sensitivity maps. The approach is tested with bioluminescence observations collected during August 2000 and 2003 in the Monterey Bay, California, area. During August 2000, BL surveys were collected during a strong wind relaxation event, while in August 2003, BL surveys were conducted during an extended (longer than a week) upwelling-favorable event. The numerical bioluminescence predictability experiments demonstrated a close agreement between observed and model-predicted short-term spatial and temporal changes of the coastal bioluminescence

Three new species of remosiid siphonophore (Siphonophora: Physonectae)

Three new species belonging to the family Resomiidae (Siphonophora: Physonectae) are described from material mainly collected by ROVs in the vicinity of Monterey Bay, California, USA, with some additional submersible-collected specimens from The Bahamas. Although these species, Resomia ornicephala, R. persica, and R. dunni, show some differences from those previously described, particularly in the shape of the nectophores, they have all been placed in the genus Resomia. They retain the basic characteristic of having two forms of tentilla on the same tentacle, the more proximal form, with aspirally coiled cnidoband, becoming reconfigured into the more distal form, usually with a zigzagged cnidoband, although in one of the new species the zigzagging of the cnidoband is less well-defined

Bioluminescent and red-fluorescent lures in a deep-sea siphonophore

Bioluminescence (light production) and fluorescence (re-emission of absorbed radiation as light) are found in an unaccountably diverse array of marine organisms, where their functions are largely unknown. Here we report a deep-sea siphonophore that twitches glowing lures to attract fish. This is rare evidence of bioluminescence used for prey attraction among nonvisual marine organisms. The lures also contain red fluorescent material that shifts the wavelength of emitted light. The existence of a red-luminescent invertebrate suggests that long-wavelength light plays a greater role in marine interactions than previously suspected

A description of two new species of the genus Erenna (Siphonophora: Physonectae: Erennidae), with notes on recently collected specimens of other Erenna species

Two new Erenna species, E. insidiator sp. nov. and E. sirena sp. nov., are described from specimens collected in the vicinity of Monterey Bay, California, and also, for E. sirena at the southern end of the Gulf of California, Mexico. Further information on the three extant Erenna species is given, based on specimens collected in the same areas. These have enabled, for instance, the identification of three types of tentilla on the tentacles of E. cornuta Pugh, 2001, rather than the two noted on the single previously known specimen. The genus is remarkable for the presence of bioluminescent lures on the tentilla of all five species. In E. sirena sp. nov. the tentilla are also covered by a red-fluorescent layer, which was briefly described by Haddock et al. (2005), and further details are given herein. Another extraordinary feature of the colonies E. sirena sp. nov. is that the main part of the tentacle, with its tentilla, can be extended away from the siphosomal stem on a long peduncle. This phenomenon also appears to occur in E. laciniata Pugh, 2001, and has not been observed before for other physonect species

Molecular phylogenetics of the Siphonophora (Cnidaria), with implications for the evolution of functional specialization

Siphonophores are a group of pelagic colonial hydrozoans (Cnidaria) that have long been of general interest because of the division of labor between the polyps and medusae that make up these “superorganisms.” These polyps and medusae are each homologous to free living animals but are generated by an incomplete asexual budding process that leaves them physiologically integrated. They are functionally specialized for different tasks and are precisely organized within each colony. The number of functional types of polyps and medusae varies across taxa, and different authors have used this character to construct phylogenies polarized in opposite directions, depending on whether they thought siphonophore evolution proceeded by a reduction or an increase in functional specialization. We have collected taxa across all major groups of siphonophores, many of which are found exclusively in the deep sea, using remotely operated underwater vehicles (ROVs) and by SCUBA diving from ships in the open ocean. We have used 52 siphonophores and four outgroup taxa to estimate the siphonophore phylogeny with molecular data from the nuclear small subunit ribosomal RNA gene (18S) and the mitochondrial large subunit ribosomal RNA gene (16S). Parsimony reconstructions indicate that functionally specialized polyps and medusae have been gained and lost across the phylogeny. Maximum likelihood and Bayesian analyses of morphological data suggest that the transition rate for decreased functional specialization is greater than the transition rate for increased functional specialization for three out of the four investigated categories of polyps and medusae. The present analysis also bears on several long-standing questions about siphonophore systematics. It indicates that the cystonects are sister to all other siphonophores, a group that we call the Codonophora. We also find that the Calycophorae are nested within the Physonectae, and that the Brachystelia, a historically recognized grouping of short-stemmed taxa, are polyphyletic

Marrus claudanielis, a new species of deep-sea physonect siphonophore (Siphonophora, Physonectae)

Marrus claudanielis, a new species of deep-sea physonect siphonophore, is described from material collected by the ROV TIBURON, off California (eastern North Pacific), and the submersible JOHNSON-SEA-LINK II, off New Jersey (western North Atlantic). Marrus claudanielis is extremely fragile and all observed specimens autotomized some of their parts during observation or collection, due to the strong contraction of the stem. The siphosomal elements, the nectophoral and bracteal canals, and the pneumatophore were all deep red in life. This species is distinguished from other Marrus species by the undivided apico-lateral ridges on the nectophores, and the hook-shaped arc of enlarged ectodermal cells, including nematocysts, overlying the distal branches of the bracteal canals

A re-examination of siphonophore terminology and morphology, applied to the description of two new prayine species with remarkable bio-optical properties

Siphonophores (Cnidaria: Hydrozoa) are dominant members of the carnivorous plankton, and they are known for their ability to produce bioluminescence. Here we describe two new calycophoran species (sub-family Prayinae) that are unique in their morphological and optical traits. One species, Gymnopraia lapislazula gen. nov., sp. nov., displays a dramatic form of blue structural coloration, and the other, Lilyopsis fluoracantha, sp. nov., bears an exceptional amount of fluorescence–enough to give a greenish cast during white-light illumination. We also introduce a consistent terminology for siphonophore axes and zooids, discuss characters important for distinguishing the known prayine genera, and suggest that the presence or absence of a disjunct pedicular canal could be of diagnostic value for the group

Description of Tottonophyes enigmatica gen. nov., sp. nov. (Hydrozoa, Siphonophora, Calycophorae), with a reappraisal of the function and homology of nectophoral canals

A new species of calycophoran siphonophore, Tottonophyes enigmatica gen. nov, sp. nov., is described. It has a unique combination of traits, some shared with prayomorphs (including two rounded nectophores) and some with clausophyid diphyomorphs (the nectophores are dissimilar, with one slightly larger and slightly to the anterior of the other, and both possess a somatocyst). Molecular phylogenetic analyses indicate that the new species is the sister group to all other diphyomorphs. A new family, Tottonophyidae, is established for it. Its phylogenetic position and distinct morphology help clarify diphyomorph evolution. The function and homology of the nectophoral canals and somatocyst is also re-examined and further clarification is given to their nomenclature. Copyright © 2018 Magnolia Press