[Medusae (Cnidaria: Hydrozoa) from a coastal upwelling zone, Culebra Bay, Pacific, Costa Rica].

Rev Biol Trop. 2012 Dec;60(4):1731-48

Authors: Rodríguez-Sáenz K, Vargas-Zamora JA, Segura-Puertas L

Abstract
The hydromedusae have an important role in marine trophic webs due to their predatory feeding habits. This is the first study of this group of gelatinous marine zooplankton in a coastal upwelling area of Central America. The composition and abundance variability of hydromedusae were studied during six months in 1999 at four stations in Culebra Bay, Gulf of Papagayo, Pacific coast of Costa Rica (10 degrees 37' N-85 degrees 40' W). A total of 53 species were identified, of which 26 are new records for Costa Rica, 21 are new records for Central America, and eight are new records for the Eastern Tropical Pacific. The more abundant species (more than 30% of the total abundance) were Liriope tetraphylla, Solmundella bitentaculata and Aglaura hemistoma. Six species occurred throughout the sampling period, 10 were present only during the dry season (December-April), and 17 were so during the rainy season (May-November). Significant differences of medusan abundances were found between seasons (dry vs. rainy). Maximum abundance (2.1 +/- 4.3ind./m3) was recorded when upwelled deeper water influenced the Bay, as indicated by local higher oxygen concentrations and lower water temperatures. The relatively high species richness of medusae found in Culebra Bay is probably related to factors like the pristine condition of the Bay, the arrival of oceanic species transported by the Equatorial Counter Current (ECC), the eastward shoaling of the Costa Rica Dome, and local currents. Illustrations of the 15 more important species are included to facilitate their identification and foster future work in the region.

PMID: 23342525 [PubMed - in process]

Swimming among a pod of sperm whales in the North Atlantic is a dolphin with an S-shaped spine.

An "ex vivo" model to evaluate toxicological responses to mixtures of contaminants in cetaceans: Integumentum biopsy slices.

Environ Toxicol. 2013 Jan 22;

Authors: Fossi MC, Casini S, Maltese S, Panti C, Spinsanti G, Marsili L

Abstract
The need for powerful new tools to detect the effects of chemical pollution, in particular of persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) on Mediterranean cetaceans led us to develop and apply a suite of sensitive biomarkers for integument biopsies of stranded and free-ranging animals. This multi-response ex vivo method has the aim to detect toxicological effects of contaminant mixtures. In the present study, we applied an ex vivo assay using skin biopsy and liver slices, combining molecular biomarkers [Western blot of Cytochrome P450 1A1 (CYP1A1) and Cytochrome P450 2B (CYP2B)] and gene expression biomarkers (Quantitative real-time PCR of CYP1A1, heat shock protein 70, estrogen receptor alpha and E2F transcription factor) in response to chemical exposure [organochlorines compounds (OCs), polybrominated diphenyl ethers (PBDEs), and PAHs] for stranded Mediterranean Stenella coeruleoalba. The main goal of this experiment was to identify the biomarker and/or a suite of biomarkers that could best detect the presence of a specific class of pollutants (OCs, PBDEs, and PAHs) or a mixture of them. This multi-response biomarker methodology revealed an high sensitivity and selectivity of responses (such as CYP1A and ER α mRNA variations after OCs and PAHs exposure) and could represent a valid future approach for the study of inter- and intra-species sensitivities to various classes of environmental contaminants. © 2013 Wiley Periodicals, Inc. Environ Toxicol, 2013.

PMID: 23339137 [PubMed - as supplied by publisher]

Torpedo-shaped machines do their part to protect whales.

Mechanical properties of dental tissues in dolphins (Cetacea: Delphinoidea and Inioidea).

Arch Oral Biol. 2013 Jan 3;

Authors: Loch C, Swain MV, van Vuuren LJ, Kieser JA, Fordyce RE

Abstract
(1) Mammalian teeth play a major role in food acquisition and processing. While most mammals are heterodont and masticate their food, dolphins are homodont with simplified tooth morphology and negligible mastication. Understanding mechanical properties of dental tissues in dolphins is fundamental to elucidate the functional morphology and biomechanics of their feeding apparatus. This paper aims to study the hardness and elastic modulus of enamel and dentine in dolphins. (2) Teeth of 10 extant species (Inioidea and Delphinoidea) were longitudinally sectioned, polished and mounted in a UMIS nanoindenter. Indentations were performed from dentine to outer enamel. Hardness and elastic modulus were calculated using the Oliver-Pharr method. (3) Mean values of hardness and elastic modulus were similar on buccal and lingual surfaces. While dentine hardness was statistically similar among species, enamel hardness varied from 3.86GPa (±0.4) in Steno bredanensis (rough-toothed dolphin) to 2.36GPa (±0.38) in Pontoporia blainvillei (franciscana). For most species, there was a gradational increase in hardness values from inner to outer enamel. Enamel and dentine elastic modulus values clearly differed among species. In enamel, it ranged from 69.32GPa (±4.08) in the rough-toothed dolphin to 13.51GPa (±2.80) in Stenella coeruleoalba (striped dolphin). For most species, elastic modulus values were highest at inner and outer enamel. (4) Differences in mechanical properties between species, and within the enamel of each species, suggest functional implications and influence of ultrastructural arrangement and chemical composition.

PMID: 23290354 [PubMed - as supplied by publisher]

Fishing, pollution and other human activities along the Yangtze River in China are driving yet another species of freshwater cetacean to the brink of extinction. That is the conclusion of a six-week survey of the river’s middle and lower stretches by the Chinese Academy of Sciences’ Institute of Hydrobiology (IHB) in Wuhan and the conservation group WWF in China.

The pygmy right whale Caperea marginata: the last of the cetotheres.

Proc Biol Sci. 2013;280(1753):20122645

Authors: Fordyce RE, Marx FG

Abstract
The pygmy right whale, Caperea marginata, is the most enigmatic of the living baleen whales (Mysticeti). Its highly disparate morphology and the virtual absence of a described fossil record have made it extremely difficult to place Caperea into a broader evolutionary context, and molecular and morphological studies have frequently contradicted each other as to the origins and phylogenetic relationships of the species. Our study of a wealth of material from New Zealand collections, representing a wide range of ontogenetic stages, has identified several new features previously unreported in Caperea, which suggest that the pygmy right whale may be the last survivor of the supposedly extinct family Cetotheriidae. This hypothesis is corroborated by both morphology-based and total evidence cladistic analyses, including 166 morphological characters and 23 taxa, representing all the living and extinct families of toothless baleen whales. Our results allow us to formally refer Caperea to Cetotheriidae, thus resurrecting the latter from extinction and helping to clarify the origins of a long-problematic living species.

PMID: 23256199 [PubMed - in process]

Highlights

Highlights

Highlights

INTESTINAL HELMINTH FAUNA OF BOTTLENOSE DOLPHIN TURSIOPS TRUNCATUS AND COMMON DOLPHIN DELPHINUS DELPHIS FROM THE WESTERN MEDITERRANEAN.

J Parasitol. 2012 Nov 27;

Authors: Quiñones R, Giovannini A, Raga JA, Fernández M

Abstract
Abstract We report on the intestinal helminth fauna of 15 bottlenose dolphins Tursiops truncatus and 6 short-beaked common dolphins Delphinus delphis from the western Mediterranean. Eight helminth species were found in bottlenose dolphin, i.e., the digeneans, Synthesium tursionis, Brachycladium atlanticum, and Pholeter gastrophilus; the nematode Anisakis sp., and the cestodes Tetrabothrius forsteri, Diphyllobothrium sp., Strobilocephalus triangularis, and tetraphyllidean plerocercoids. Brachycladium atlanticum, S. triangularis, and tetraphyllidean plerocercoids are new host records. No T. forsteri had previously been reported in Mediterranean bottlenose dolphins. Three species of helminths were recorded in the common dolphin, i.e., the digenean, Synthesium delamurei (which was a new host record), and the cestodes, T. forsteri and tetraphyllidean plerocercoids. The intestinal helminth communities of bottlenose and common dolphins are depauperate, similar to that of other cetacean species, but those from bottlenose dolphins harbored a higher number of helminth species. This study supports the notion that oceanic cetaceans, such as common dolphins, have a comparatively poorer helminth fauna than that of neritic species, as are bottlenose dolphins, because the likelihood of parasite recruitment is decreased.

PMID: 23186358 [PubMed - as supplied by publisher]

Highlights

Trophy hunting is increasingly considered as a good tool to fund conservation but rare species could be highly affected by this activity. The upgrade of a species’ International Union for Conservation of Nature status to the endangered category leads to an increase in the number of trophies recorded in one of the largest hunting clubs. The value attributed to species rarity in trophy hunting and likely in other activities could prevent the application of protection measures aimed at lowering their exploitation. Photograph by St�phanie Periquet.

The world's rarest whale.

Curr Biol. 2012 Nov 6;22(21):R905-6

Authors: Thompson K, Baker CS, van Helden A, Patel S, Millar C, Constantine R

Abstract
The vast expanses of the South Pacific Ocean have, until recently, concealed the identity of the world's rarest whale, the spade-toothed beaked whale (Mesoplodon traversii). Based on the scarcity of records and the total absence of previous sightings, this species is the least known species of whale and one of the world's rarest living mammals. Two individuals of this species, previously known from only two skull fragments and a mandible, were recently discovered beach-cast in New Zealand. Although initially misidentified, we have used DNA analysis to reveal their true identity. We provide the first morphological description and images of this enigmatic species. This study highlights the importance of DNA typing and reference collections for the identification of rare species.

PMID: 23137682 [PubMed - in process]

Not extinct after all. Probably, anyway

A pair of rare whales that boffins thought might be extinct has washed up on a New Zealand beach.…