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Rolamdo González-josé - One of the best experts on this subject based on the ideXlab platform.
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Allometry and Ontogeny in the Vertebral Column of Southern Hemisphere Dolphins: a 3D Morphofunctional Approach
Journal of Mammalian Evolution, 2020Co-Authors: María Constanza Marchesi, Matías S. Mora, Silvana L. Dans, Rolamdo González-joséAbstract:Commerson’s dolphin ( Cephalorhynchus commersonii ), Peale’s dolphin ( Lagenorhynchus australis ), dusky dolphin ( Lagenorhynchus obscurus ), and hourglass dolphin ( Lagenorhynchus cruciger ) are closely related species occurring in the Southern Hemisphere. Even though they are partially sympatric, they have evolved towards diverse foraging strategies, prey, and habitat preferences. Size variation occurs both among and within species. Our goal was to study the allometric patterns and ontogenetic trajectories in the vertebral column of these dolphins related to their ecology. We choose nine functionally homologous vertebrae in each column and digitized five different tridimensional configurations, containing 28 to 41 landmarks depending on the functional region under analysis. We explored different levels of allometry (static, ontogenetic, and evolutionary) using multivariate regressions of shape vs. log-transformed centroid size. We compared ontogenetic allometry regression vectors to evidence differences in growth patterns. Finally, we calculated Procrustes distances of shape configurations to determine the timing of shape shifts. Of the studied species, When compared to the Lagenorhynchus species, Commerson’s dolphin showed the highest degrees of allometry, both static and ontogenetic. The macroevolutive trends indicate a high degree of evolutionary morphological change, which could be associated with the rapid evolutionary radiation proposed for the group. This is the first time that allometric changes are studied in small cetaceans by means of 3D geometric morphometrics.
Geoffrey Foster - One of the best experts on this subject based on the ideXlab platform.
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Twin foetuses in an Atlantic white-sided dolphin ( Lagenorhynchus acutus ) stranded on the coast of Scotland, UK
Journal of the Marine Biological Association of the United Kingdom, 2016Co-Authors: Nicholas J Davison, Andrew Brownlow, Mark P Dagleish, Robert J Reid, Geoffrey Foster, Mariel Ten Doeschate, F.l. Read, Jason P. BarleyAbstract:The present study is the first record of twinning in Lagenorhynchus acutus and indeed any Lagenorhynchus sp. Both foetuses were male and located in the left uterine horn, had distinct grossly normal placentas and amniotic sacs, and were therefore likely dizygotic twins. The twins were an incidental finding in an animal that died of a systemic Brucella ceti infection.
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first report of brucella ceti associated meningoencephalitis in a long finned pilot whale globicephala melas
Diseases of Aquatic Organisms, 2015Co-Authors: Nicholas J Davison, Mark S Koylass, Lorraine L Perrett, Andrew Brownlow, Barry Mcgovern, Emmajane Dale, Mark P Dagleish, Geoffrey FosterAbstract:: Fatal Brucella ceti infection with histological lesions specific to the central nervous system has been described in only 3 species of cetaceans: striped dolphins Stenella coeruleoalba, Atlantic white-sided dolphins Lagenorhynchus acutus and short-beaked common dolphins Delphinus delphis. This paper describes the first report of a B. ceti-associated meningoencephalitis in a long-finned pilot whale Globicephala melas, showing the increasing range of species susceptibility. Brucella was recovered in larger numbers from cerebrospinal fluid than from brain tissue and is the sample of choice for isolation.
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Is Dolphin Morbillivirus Virulent for White-Beaked Dolphins (Lagenorhynchus albirostris)?
Veterinary pathology, 2014Co-Authors: C. E. Van Elk, Thierry Jauniaux, Geoffrey Foster, M. W. G. Van De Bildt, Sjoukje Hiemstra, P.r.w.a Van Run, J. Meerbeek, A.d.m.e. Osterhaus, Thijs KuikenAbstract:The virulence of morbilliviruses for toothed whales (odontocetes) appears to differ according to host species. In 4 species of odontocetes, morbilliviruses are highly virulent, causing large-scale epizootics with high mortality. In 8 other species of odontocetes, including white-beaked dolphins (Lagenorhynchus albirostris), morbilliviruses have been found as an incidental infection. In these species, the virulence of morbilliviruses is not clear. Therefore, the admission of 2 white-beaked dolphins with morbillivirus infection into a rehabilitation center provided a unique opportunity to investigate the virulence of morbillivirus in this species. By phylogenetic analysis, the morbilliviruses in both animals were identified as a dolphin morbillivirus (DMV) most closely related to that detected in a white-beaked dolphin in Germany in 2007. Both animals were examined clinically and pathologically. Case No. 1 had a chronic neural DMV infection, characterized by polioencephalitis in the cerebrum and morbillivirus antigen expression limited to neurons and glial cells. Surprisingly, no nervous signs were observed in this animal during the 6 months before death. Case No. 2 had a subacute systemic DMV infection, characterized by interstitial pneumonia, leucopenia, lymphoid depletion, and DMV antigen expression in mononuclear cells and syncytia in the lung and in mononuclear cells in multiple lymphoid organs. Cause of death was not attributed to DMV infection in either animal. DMV was not detected in 2 contemporaneously stranded white-beaked dolphins. Stranding rate did not increase in the region. These results suggest that DMV is not highly virulent for white-beaked dolphins.
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is dolphin morbillivirus virulent for white beaked dolphins Lagenorhynchus albirostris
Veterinary Pathology, 2014Co-Authors: Thierry Jauniaux, Geoffrey Foster, C. E. Van Elk, M. W. G. Van De Bildt, Sjoukje Hiemstra, P.r.w.a Van Run, J. Meerbeek, A.d.m.e. Osterhaus, Thijs KuikenAbstract:The virulence of morbilliviruses for toothed whales (odontocetes) appears to differ according to host species. In 4 species of odontocetes, morbilliviruses are highly virulent, causing large-scale epizootics with high mortality. In 8 other species of odontocetes, including white-beaked dolphins (Lagenorhynchus albirostris), morbilliviruses have been found as an incidental infection. In these species, the virulence of morbilliviruses is not clear. Therefore, the admission of 2 white-beaked dolphins with morbillivirus infection into a rehabilitation center provided a unique opportunity to investigate the virulence of morbillivirus in this species. By phylogenetic analysis, the morbilliviruses in both animals were identified as a dolphin morbillivirus (DMV) most closely related to that detected in a white-beaked dolphin in Germany in 2007. Both animals were examined clinically and pathologically. Case No. 1 had a chronic neural DMV infection, characterized by polioencephalitis in the cerebrum and morbillivirus antigen expression limited to neurons and glial cells. Surprisingly, no nervous signs were observed in this animal during the 6 months before death. Case No. 2 had a subacute systemic DMV infection, characterized by interstitial pneumonia, leucopenia, lymphoid depletion, and DMV antigen expression in mononuclear cells and syncytia in the lung and in mononuclear cells in multiple lymphoid organs. Cause of death was not attributed to DMV infection in either animal. DMV was not detected in 2 contemporaneously stranded white-beaked dolphins. Stranding rate did not increase in the region. These results suggest that DMV is not highly virulent for white-beaked dolphins.
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ISOLATION OF BRUCELLA SPECIES FROM CETACEANS, SEALS AND AN OTTER
Veterinary Record, 1996Co-Authors: Geoffrey Foster, K. L. Jahans, Robert J Reid, H. M. RossAbstract:Brucella organisms which differed from the recognised species of the genus, were isolated from nine seals, eight cetaceans and one otter. A method is described for the isolation of Brucella species from sea mammals and the first isolations of Brucella species are recorded from an Atlantic white-sided dolphin ( Lagenorhynchus acutus ), two striped dolphins ( Stenella coeuleoalba ), a hooded seal ( Cystophora cristata ), a grey seal ( Halichoerus grypus ) and a European otter ( Lutra lutra ). There were differences in the culture media required for the primary isolation of the organisms and in their dependency on carbon dioxide. Subcutaneous lesions, when present, always yielded a confluent growth. The organisms were isolated from seven of 14 spleen samples and also from the mammary glands, uterus, testes and blood and the mandibular, gastric, iliac, sub-lumbar and colorectal lymph nodes.
Bernd Würsig - One of the best experts on this subject based on the ideXlab platform.
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Sex-specific variation in conspecific-acquired marking prevalence among dusky dolphins (Lagenorhynchus obscurus)
Canadian Journal of Zoology, 2015Co-Authors: Dara N. Orbach, Jane M. Packard, Sarah Piwetz, Bernd WürsigAbstract:Despite logistical challenges that limit direct observations of behavior for some species, physical scars can provide indirect evidence of aggression. Dusky dolphins (Lagenorhynchus obscurus (Gray, 1828)) off Kaikoura, New Zealand, derive most of the notches and scars on their dorsal fins from conspecifics. However, aggressive encounters have rarely been observed in this sexually monomorphic species. If injurious interactions are associated with intrasexual competition among males but not females, we predicted males would have more conspecific-acquired markings than females. High-quality dorsal fin photographs of dolphins of known sex (n = 79) were collected during boat-based surveys off Kaikoura. We measured three quantitative variables (notch height ratio, notch depth ratio, and dorsal fin rake direction) and one qualitative variable that scored the overall prevalence of markings (notches and scars). All four measures yielded consistent results. Males had significantly more conspecific-acquired markings...
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Copulation rate declines with mating group size in dusky dolphins (Lagenorhynchus obscurus)
Canadian Journal of Zoology, 2015Co-Authors: Dara N. Orbach, Gil G. Rosenthal, Bernd WürsigAbstract:Males in polygamous species often engage in intrasexual competition for mates. If females actively evade mating attempts, it may benefit males to cooperate to restrict female movement, as has been found in some mammals. We tested if male dusky dolphins (Lagenorhynchus obscurus (Gray, 1828)) cooperate or compete during group mating chases. If they cooperate, then the per-male probability of copulating should increase with group size; if they compete, then the probability should decrease. We followed mating groups by boat during the breeding season (October 2013 - January 2014) off Kaikoura, New Zealand. The copulation rate per male decreased with increasing group size and with the number of noncopulating males in proximity to a copulating female. Male dusky dolphins have multiple mates and appear to use sperm and exploitative scramble competition. Males may remain in mating groups despite competition because there are alliances within the groups, they are unable to exclude rivals from joining a group, the time and energy costs of searching for unescorted females exceed the costs of reduced mating opportunities in a group, they receive other direct or indirect benefits that offset the costs of reduced mating opportu- nities, or they are in the group largely for social learning rather than procreation. Resume : Les mâles d'especes polygames se font souvent concurrence pour les femelles. Si les femelles evitent activement les tentatives d'accouplement, il pourrait etre avantageux pour les mâles de cooperer pour restreindre les deplacements des femelles, un comportement observe chez certains mammiferes. Nous avons verifie si les lagenorhynques obscurs (Lagenorhynchus obscurus (Gray, 1828)) mâles cooperent ou se font concurrence durant les poursuites nuptiales en groupe. S'ils cooperent, la probabilite de copulation par individu mâle devrait augmenter parallelement ala taille du groupe; s'ils se font concurrence, cette probabilite devrait diminuer. Nous avons suivi par bateau des groupes reproducteurs durant la saison de reproduction (octobre 2013 ajanvier 2014) au large de Kaikoura (Nouvelle-Zelande). Plus le groupe etait grand et plus le nombre de mâles non copulateurs aproximite d'une femelle copulatrice etait eleve, plus le taux de copulation par mâle etait faible. Les lageno- rhynques obscurs mâles ont de multiples partenaires et semblent utiliser la concurrence spermatique et en melee. Les mâles peuvent demeurer dans des groupes de reproducteurs malgre la concurrence parce qu'il y a des alliances au sein de ces groupes, qu'ils ne peuvent exclure des rivaux d'un groupe, que les couts en temps et en energie de la quete d'une femelle non escortee depassent les couts associes ala reduction des possibilites d'accouplement dans le groupe, qu'ils en tirent d'autres avantages directs ou indirects qui compensent les couts de la reduction des possibilites d'accouplement ou qu'ils sont dans le groupe principalement ades fins d'apprentissage social plutot que de procreation. (Traduit par la Redaction) Mots-cles : cooperation, copulation, concurrence entre individus du meme sexe, concurrence en melee, lagenorhynque obscur, Lagenorhynchus obscurus.
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Evasive behaviours of female dusky dolphins (Lagenorhynchus obscurus) during exploitative scramble competition
Behaviour, 2015Co-Authors: Dara N. Orbach, Jane M. Packard, Theresa Kirchner, Bernd WürsigAbstract:When males engage in scramble competition, are females non-evasive recipients of male coercion or evasive? Small groups of male dusky dolphins ( Lagenorhynchus obscurus) engage in exploitative (non-interference) scramble competition for access to oestrous females near Kaikoura, New Zealand. We conducted behavioural sequence analyses of videos of 48 mating groups with continuous records and focal individual follows of females. We determined (1) the frequency and type of behaviours (non-evasive vs. evasive), (2) the variation in simple transition probabilities of behaviours leading to a copulatory position associated with female resistance and non-resistance and (3) the variation in female responses to male behaviours throughout focal follows. Females exhibited frequent active evasive manoeuvers following male behaviours. Copulation sequences were highly variable and most complex when terminated by females. Females altered responses to male signals, one aspect of mate choice potentially favouring male endurance.
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development of leaps in dusky dolphin Lagenorhynchus obscurus calves
Behaviour, 2014Co-Authors: Sierra Deutsch, Bernd Würsig, Heidi C. PearsonAbstract:Leaping is a highly conspicuous behavior in cetaceans that may function in cooperative hunting and social bonding, thereby converging with forms of intra-specific communication present in other social mammals. However, few studies have analyzed the ontogeny of leaping, an important aspect in determining the adaptive significance of this behavior. The objective of our study was to quantify the ontogeny of leaping in dusky dolphins, a highly acrobatic species that engages in a variety of aerial displays. We tested the hypotheses that: (1) leap frequency changes with calf age, (2) frequency of leap type varies with calf age and (3) frequency of leap type varies by behavioral state. Data were collected off Kaikoura, New Zealand through boat-based group focal follows of nursery groups from October 2006–May 2007. We analyzed data from 73 nursery group encounters according to age category (young calf, yearling) and season (early, late). Early young calves leapt less frequently than late young calves (p<0.01), but leap frequency did not appear to differ among older calves. Calves learned noisy leaps first, followed by clean leaps, then coordinated leaps, and finally acrobatic leaps as indicated by the positive correlations between week (i.e., calf age) and frequency of clean (p<0.01), acrobatic (p<0.01) and coordinated (p<0.05) leaps. The relationship between behavioral state and frequency of leap type was not significant. These results indicate that nursery groups represent an important environment for healthy physical and social development of calves. Furthermore, while calves appear to learn the mechanics of leaping individually, they appear to learn the context in which the leaps are performed from conspecifics. This indicates that, as for other socially-complex mammals such as other cetaceans, primates, and social carnivores, social learning may be an important component in the ontogeny of dusky dolphin behavior.
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Dusky Dolphin: Lagenorhynchus obscurus
Encyclopedia of Marine Mammals, 2009Co-Authors: Koen Van Waerebeek, Bernd WürsigAbstract:Publisher Summary The stocky dusky dolphin from the Southern Hemisphere and the Pacific whitesided dolphin, Lagenorhynchus obliquidens , from the northern Pacific Ocean are considered phylogenetically closely related species despite the absence of a fossil record. Some researchers suggested that L. obliquidens could almost equally well be regarded as a subspecies of the dusky dolphin. The smallish dusky dolphin can be recognized by its short beak and the bluish black to dark gray of the dorsal field contrasting with the white belly, as well as the light gray of the thoracic patch and two-pronged flank patch. The dark lips and eye patch also stand out. The falcate dorsal fin is two-toned with a dark leading edge. Unlike in L. obliquidens , the linear dorsal flank blaze does not extend farther anteriorly than about mid-body. Heavily pigmented specimens are found off Peru and Argentina. The holotype of Delphinus fitzroy caught off Argentina from Darwin's ship, Beagle, was such a melanistic form. Various cases of anomalous, piebald pigmentation are probably equivalent to so-called partial albinism.
Jeanmarie Bouquegneau - One of the best experts on this subject based on the ideXlab platform.
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marine mammals from northeast atlantic relationship between their trophic status as determined by δ13c and δ15n measurements and their trace metal concentrations
Marine Environmental Research, 2003Co-Authors: Krishna Das, Cristina Beans, Ludo Holsbeek, Gerard Mauger, Simon Berrow, Emer Rogan, Jeanmarie BouquegneauAbstract:The relationship between trophic position through delta13C and delta15N and trace metal concentrations (Zn, Cd, Cu and Hg) was investigated in the tissues of six marine mammal species from the Northeast Atlantic: striped dolphin Stenella coeruleoalba, common dolphin, Delphinus delphis, Atlantic white-sided dolphin Lagenorhynchus acutus, harbour porpoise Phocoena phocoena, white beaked-dolphin Lagenorhynchus albirostris, grey seal Halichoerus grypus stranded on French Channel and Irish coasts. White-beaked dolphins, harbour porpoises, white-sided dolphins, common and striped dolphins display the same relative and decreasing trophic position, as measured by delta15N values, along both the Irish and French channel coasts, reflecting conservative trophic habits between these two places. Hepatic and renal Cd concentrations were significantly correlated to muscle delta13C and delta15N values while Hg, Zn and Cu did not. These results suggest that Cd accumulation is partly linked to the diet while other factors such as age or body condition might explain Hg, Zn or Cu variability in marine mammals. Combined stable isotope and trace metal analyses appear to be useful tools for the study of marine mammal ecology.
Hao Liu - One of the best experts on this subject based on the ideXlab platform.
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Morphological parameters of dolphins (Lagenorhynchus obliquidens) and 3-D models.
2019Co-Authors: Hiroto Tanaka, Yusuke Uchida, Masashi Nakamura, Teruaki Ikeda, Hao LiuAbstract:Morphological parameters of dolphins (Lagenorhynchus obliquidens) and 3-D models.
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Frozen museum specimen of a Pacific white-sided dolphin (Lagenorhynchus obliquidens) scanned with a portable 3-D scanner.
2019Co-Authors: Hiroto Tanaka, Yusuke Uchida, Masashi Nakamura, Teruaki Ikeda, Hao LiuAbstract:Frozen museum specimen of a Pacific white-sided dolphin (Lagenorhynchus obliquidens) scanned with a portable 3-D scanner.
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Video recording setup.
2019Co-Authors: Hiroto Tanaka, Yusuke Uchida, Masashi Nakamura, Teruaki Ikeda, Hao LiuAbstract:(A) The Pacific white-sided dolphin (Lagenorhynchus obliquidens) recorded in this study. White ointments were painted as markers for motion tracking. Beak, lateral, and fluke markers indicated by solid magenta circles were used in this study, while the other markers indicated by dotted cyan circles were not used. (B) Overview of the water tank at Yokohama Hakkeijima Sea Paradise. The water depth is 6 m. The high-speed video cameras do not appear in this photo. Instead, positions and directions of the cameras are indicated with white arrows. The floating island in this photo was removed when the dolphin performed the jump.
