Search results for "Biologia marina"
showing 10 items of 14 documents
Use of nursery areas by the extinct megatooth shark Otodus megalodon (Chondrichthyes: Lamniformes)
2020
Nursery areas are fundamental for the success of many marine species, particularly for large, slow-growing taxa with low fecundity and high age of maturity. Here, we examine the population size-class structure of the extinct gigantic shark Otodus megalodon in a newly described middle Miocene locality from Northeastern Spain, as well as in eight previously known formations (Temblor, Calvert, Pisco, Gatún, Chucunaque, Bahía Inglesa, Yorktown and Bone Valley). In all cases, body lengths of all individuals were inferred from dental parameters and the size-class structure was estimated from kernel probability density functions and Gaussian mixture models. Our analyses support the presence of fi…
Integrative taxonomy of crustacean y-larvae (Thecostraca: Facetotecta) using laboratory-rearing and molecular analyses of single specimens, with the …
2022
AbstractFacetotecta, the taxon established for ‘y-larvae’, is the last major crustacean group for which the adult stage remains unknown. With only 14 described nominal species, all in the genus Hansenocaris, their incompletely known life cycle, small size and dearth of molecular data have hampered assessments of their true species diversity. Based on field studies during which > 11 000 y-larvae were sampled, a new integrative approach for studying the taxonomy of y-larvae is outlined. It focuses on last-stage nauplii and y-cyprids and includes methods for rearing lecithotrophic y-larvae for documenting the morphology of specimens with live photomicroscopy and scanning electron micros…
Revision of the taxonomic position ofPseudocyprettaKlie, 1932 (Ostracoda: Cyprididae), with a redescription ofP. maculataKlie, 1932
2022
AbstractPseudocypretta maculata Klie, 1932, type species of the genus, is redescribed based on new material from Thailand. The main diagnostic features of the species are the presence of marginal septa, presence of Wouters organ on the first antenna, strongly serrated claw G2 of the second antenna (A2), small β seta on the mandibular palp, elongated terminal segment of the maxillular palp, smooth and large bristles on the third endite of the maxillula, undivided penultimate segment of the second thoracopod (T2), absence of d1 seta on the T2, completely separated terminal segment of the third thoracopod, absence of a pincer organ, and reduced caudal ramus with a triangular base. The taxonomi…
Bioluminescent-like squamation in the galeomorph shark Apristurus ampliceps (Chondrichthyes: Elasmobranchii)
2018
Galeomorph sharks constitute the most taxonomically and ecologically diverse superorder of living selachians. Despite comprising several typically deep-water taxa, no bioluminescent species have been reported in this group so far. Interestingly, the study of shark squamation has been revealed in recent years to be a good proxy for inferring some ecological aspects of poorly known species. In particular, the high morphological specificity of the dermal denticles and the squamation patterns of all currently-known bioluminescent sharks could constitute a potential tool for predicting bioluminescence in both fossil and living taxa. Following this idea, we provide the first evidence supporting t…
Pathogenic strains of Shewanella putrefaciens contain plasmids that are absent in the probiotic strain Pdp11
2022
Shewanella putrefaciens Pdp11 is a strain described as a probiotic for use in aquaculture. However, S. putrefaciens includes strains reported to be pathogenic or saprophytic to fish. Although the probiotic trait has been related to the presence of a group of genes in its genome, the existence of plasmids that could determine the probiotic or pathogenic character of this bacterium is unknown. In the present work, we searched for plasmids in several strains of S. putrefaciens that differ in their pathogenic and probiotic character. Under the different conditions tested, plasmids were only found in two of the five pathogenic strains, but not in the probiotic strain nor in the two saprophytic s…
A multiplex PCR for the detection of Vibrio vulnificus hazardous to human and/or animal health from seafood
2022
Vibrio vulnificus is a zoonotic pathogen linked to aquaculture that is spreading due to climate change. The pathogen can be transmitted to humans and animals by ingestion of raw shellfish or seafood feed, respectively. The aim of this work was to design and test a new procedure to detect V. vulnificus hazardous to human and/or animal health in food/feed samples. For this purpose, we combined a pre-enrichment step with multiplex PCR using primers for the species and for human and animal virulence markers. In vitro assays with mixed DNA from different Vibrio species and Vibrio cultures showed that the new protocol was 100 % specific with a detection limit of 10 cfu/mL. The protocol was succes…
Metagenomics of the Mucosal Microbiota of European Eels
2014
ABSTRACT European eels are an economically important and threatened species that are prone to rapid collapse in farm conditions. Using metagenomics, we show that the eel mucosal microbiota has specific features distinguishing it from the surrounding aquatic community. This is a first step in dissecting the resident microbiota of this critical barrier that may have implications for maintenance of healthy eel populations.
Taxonomic revision of the Atlantic and Pacific species of Ligophorus (Monogenea, Dactylogyridae) from mullets (Teleostei, Mugilidae) with the proposa…
2013
A revision of the Atlantic and Pacific species of Ligophorus Euzet et Suriano, 1977 based on abundant newly sampled material from mugilids of the Mediterranean Sea, Sea of Japan and South China Sea, as well as available type and voucher specimens, is presented. All 35 nominal species of Ligophorus known from the Atlantic and the Pacific waters are treated. Of them, 30 are considered valid, one incertae sedis (L. leporinus), one species inquirendae (L. chongmingensis), two junior synonyms (L. euzeti and L. gussevi) and one is transferred to another genus. Three new species of Ligophorus are described: L. triangularis, L. miroshnichenki, and L. rectus. An amended diagnosis of Ligophorus is gi…
Quando i sacchetti di plastica sono utili allo studio della biologia marina
2022
De extinción en extinción: la vida se reinventa una y otra vez
2020
Episodios de extinción y recuperación que afectaron el desarrollo de la vida en la Tierra, cada uno extendido por lapsos de millones de años, más largos que la historia completa de la especie humana. Se ilustran mediante ejemplos del registro fósil marino del Mesozoico temprano, centrándonos en los invertebrados marinos del tiempo que transcurrió entre el fin del Pérmico y el del Jurásico temprano, es decir, entre hace unos 252 y 174 Ma. Los fósiles encontrados en el actual territorio argentino, en sitios que entonces estuvieron bajo el mar, aportan información útil para analizar este lapso de tiempo que contiene dos de las grandes extinciones señaladas y también una menor.