| two new species of litobothrium dailey, 1969 (cestoda: litobothriidea) from thresher sharks in the gulf of california, mexico, with redescriptions of two species in the genus. | as part of a survey of the metazoan parasites of elasmobranchs of the gulf of california, mexico, the spiral intestines of 10 pelagic thresher sharks alopias pelagicus and one bigeye thresher shark a. superciliosus were examined for tapeworms. eight of the a. pelagicus specimens examined were found to host litobothrium amplifica and l. daileyi. both tapeworm species are redescribed based on examination of this new material with light and scanning electron microscopy, and the ranges of most of th ... | 2001 | 11302614 |
| identification of factors influencing shark catch and mortality in the marshall islands tuna longline fishery and management implications. | recent average annual catches of sharks by tuna longline vessels fishing in the republic of the marshall islands (rmi) are estimated to be between 1583 and 2274 t. although 22 shark species have been recorded by the observer programme for this fishery, 80% of the annual catch comprises only five species: blue shark prionace glauca, silky shark carcharhinus falciformis, bigeye thresher shark alopias superciliosus, pelagic thresher shark alopias pelagicus and oceanic whitetip shark carcharhinus lo ... | 2012 | 22497410 |
| [fishery of oceanic and coastal sharks in colima, jalisco and michoacán]. | shark fishery is one of the most important activities in the mexican pacific coast, nevertheless, there is few data available about the specific captures done by the fleet along the coast. this study describes fishery biology aspects of the shark species catched by the semi-industrial long-line fleet of manzanillo. monthly samplings were made on board of these vessels during an annual period from april 2006 to april 2007. captured species composition (n = 1 962 organisms) was represented by nine ... | 2011 | 21721232 |
| the vascular morphology and in vivo muscle temperatures of thresher sharks (alopiidae). | the thresher sharks comprise a single family (alopiidae) of pelagic sharks most easily recognized by the elongate dorsal lobe of their caudal fin. despite morphological similarities among the alopiids, the common thresher (alopias vulpinus) is unique in that its red, aerobic myotomal muscle (rm) is medially positioned (i.e., closer to the vertebrae), its systemic blood is supplied through a lateral circulation which give rise to counter-current heat exchanging retia, and it is capable of regiona ... | 2011 | 21688299 |
| the red muscle morphology of the thresher sharks (family alopiidae). | a more medial and anterior position of the red aerobic myotomal muscle (rm) and the presence of a vascular counter-current heat exchange system provide the functional elements that facilitate regional rm endothermy in tunas, lamnid sharks and the common thresher shark (alopias vulpinus). the convergent rm morphology among all species capable of rm endothermy suggests that rm position is a strong predictor of fish endothermic capacity. the present study investigated the comparative rm morphology ... | 2005 | 16272248 |
| microsatellite loci in the tiger shark and cross-species amplification using pyrosequencing technology. | the tiger shark (galeocerdo cuvier) has a global distribution in tropical and warm temperate seas, and it is caught in numerous fisheries worldwide, mainly as bycatch. it is currently assessed as near threatened by the international union for conservation of nature (iucn) red list. in this study, we identified nine microsatellite loci through next generation sequencing (454 pyrosequencing) using 29 samples from the western atlantic. the genetic diversity of these loci were assessed and revealed ... | 2016 | 27635306 |
| tooth development and histology patterns in lamniform sharks (elasmobranchii, lamniformes) revisited. | the dentition of lamniforme sharks exhibits several characters that have been used extensively to resolve the phylogenetic relationships of extant taxa, yet some uncertainties remain. also, the development of different teeth of a tooth file within the jaws of most extant lamniforms has not been documented to date. high-resolution micro-computed tomography is used here to re-evaluate the importance of two dental characters within the order lamniformes, which were considered not to be phylogenetic ... | 2016 | 27587092 |
| habitat use and diel vertical migration of bigeye thresher shark: overlap with pelagic longline fishing gear. | pelagic longliners targeting swordfish and tunas in oceanic waters regularly capture sharks as bycatch, including currently protected species as the bigeye thresher, alopias superciliosus. fifteen bigeye threshers were tagged with pop-up satellite archival tags (psats) in 2012-2014 in the tropical northeast atlantic, with successful transmissions received from 12 tags for a total of 907 tracking days. marked diel vertical movements were recorded on all specimens, with most of the daytime spent i ... | 2015 | 26559889 |
| gill morphometrics of the thresher sharks (genus alopias): correlation of gill dimensions with aerobic demand and environmental oxygen. | gill morphometrics of the three thresher shark species (genus alopias) were determined to examine how metabolism and habitat correlate with respiratory specialization for increased gas exchange. thresher sharks have large gill surface areas, short water-blood barrier distances, and thin lamellae. their large gill areas are derived from long total filament lengths and large lamellae, a morphometric configuration documented for other active elasmobranchs (i.e., lamnid sharks, lamnidae) that augmen ... | 2015 | 25703507 |
| the complete mitochondrial genome of the big-eye thresher shark, alopias superciliosus (chondrichthyes, alopiidae). | the complete mitochondrial genome of the big-eye thresher shark was sequenced using a polymerase chain reaction (pcr)-based method. the total length of mitochondrial dna is 16,719 bp and includes 13 protein-coding genes, 2 ribosomal rna, 22 transfer rna genes, 1 replication origin region and 1 control region. the mitochondrial gene arrangement of the big-eye thresher shark is the same as the one observed in the most vertebrates. base composition of the genome is a (31.8%), t (28.9%), c (25.8%) a ... | 2014 | 23631367 |
| retinal ganglion cell distribution and spatial resolving power in elasmobranchs. | the total number, distribution and peak density of presumed retinal ganglion cells was assessed in 10 species of elasmobranch (nine species of shark and one species of batoid) using counts of nissl-stained cells in retinal wholemounts. the species sampled include a number of active, predatory benthopelagic and pelagic sharks that are found in a variety of coastal and oceanic habitats and represent elasmobranch groups for which information of this nature is currently lacking. the topographic dist ... | 2008 | 18679025 |
| sperm storage in male elasmobranchs: a description and survey. | two basic types of spermatozoan aggregates, spermatophores and spermatozeugmata, found in 14 different species of sharks, one species of skate, and one species of chimaera (holocephalan), were investigated using light and scanning electron microscopy. spermatophores, aggregates (usually 1,000-6,000 microns in diameter and larger) of randomly clumped sperm embedded in and surrounded by an eosinophilic matrix, were found in alopias superciliosus, odontaspis taurus, carcharodon carcharias, isurus o ... | 1994 | 8169955 |
| anatomical studies of the coronary system in elasmobranchs: i. coronary arteries in lamnoid sharks. | a study of the anatomy of coronary arteries has been done in five shark species of the order lamniformes: isurus oxyrinchus, isurus paucus, lamna nasus, alopias superciliosus, and alopias vulpinus. the study, which included 26 specimens, was carried out with the injection-corrosion technique, obtaining internal casts of the main trunks and coronary arterial branches. the results have shown a high degree of constancy in the coronary patterns in all species and a number of general features common ... | 1990 | 2321561 |