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Giovanni Bianucci - One of the best experts on this subject based on the ideXlab platform.
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Sperm and Beaked Whales, Evolution
Encyclopedia of Marine Mammals, 2018Co-Authors: Giovanni Bianucci, Christian De MuizonAbstract:Summary Although extant sperm whales (Kogiidae and Physeteridae) and beaked whales (Ziphiidae) share a series of ecological and morphological traits, the continuously improving fossil record yields stem taxa whose foraging strategies and paleoecology are hypothesized to differ markedly from modern species: extinct macroraptorial sperm whales and raptorial snapping beaked whales, most likely feeding on epipelagic prey. The available paleontological data suggest the parallel progressive emergence, in physeteroids and ziphiids, of characters related to a specialization toward deep diving and suction feeding.
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New beaked whales from the late Miocene of Peru and evidence for convergent evolution in stem and crown Ziphiidae (Cetacea, Odontoceti)
PeerJ, 2016Co-Authors: Giovanni Bianucci, Claudio Di Celma, Mario UrbinaAbstract:: The Ziphiidae (beaked whales) represent a large group of open-ocean odontocetes (toothed cetaceans), whose elusive and deep diving behavior prevents direct observation in their natural habitat. Despite their generally large body size, broad geographical distribution, and high species number, ziphiids thus remain poorly known. Furthermore, the evolutionary processes that have led to their extreme adaptations and impressive extant diversity are still poorly understood. Here we report new fossil beaked whales from the late Miocene of the Pisco Formation (southern Peru). The best preserved remains here described are referred to two new genera and species, the Messinian Chavinziphius maxillocristatus and the Tortonian Chimuziphius coloradensis, based on skull remains from two marine vertebrate-rich localities: Cerro Los Quesos and Cerro Colorado, respectively. C. maxillocristatus is medium sized retains a complete set of functional lower teeth, and bears robust rostral maxillary crests similar to those of the extant Berardius. By contrast, C. coloradensis is small and characterized by large triangular nasals and moderately thickened premaxillae that dorsally close the mesorostral groove. Both species confirm the high past diversity of Ziphiidae, the richest cetacean family in terms of the number of genera and species. Our new phylogenetic and biogeographical analyses depart markedly from earlier studies in dividing beaked whales into two major clades: the Messapicetus clade, which, along with other stem ziphiids, once dominated the southeastern Pacific and North Atlantic; and crown Ziphiidae, the majority of which are found in deep-water regions of the Southern Ocean, with possible subsequent dispersal both globally (Mesoplodon and Ziphius) and to the cooler waters of the northern oceans (Berardius and Hyperoodon). Despite this relatively clear separation, both lineages seem to follow similar evolutionary trends, including (1) a progressive reduction of dentition; (2) an increase in the compactness and thickness of the rostral bones; (3) similar changes in facial morphology (e.g., elevation of the vertex); and (4) an increase of body size. We suggest that these trends may be linked to a convergent ecological shift to deep diving and suction feeding.
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no deep diving evidence of predation on epipelagic fish for a stem beaked whale from the late miocene of peru
Proceedings of The Royal Society B: Biological Sciences, 2015Co-Authors: Olivier Lambert, Mario Urbina, Claudio Di Celma, Klaas Post, Benjamin Ramassamy, Alberto Collareta, Walter Landini, Giovanni BianucciAbstract:Although modern beaked whales (Ziphiidae) are known to be highly specialized toothed whales that predominantly feed at great depths upon benthic and benthopelagic prey, only limited palaeontological data document this major ecological shift. We report on a ziphiid–fish assemblage from the Late Miocene of Peru that we interpret as the first direct evidence of a predator–prey relationship between a ziphiid and epipelagic fish. Preserved in a dolomite concretion, a skeleton of the stem ziphiid Messapicetus gregarius was discovered together with numerous skeletons of a clupeiform fish closely related to the epipelagic extant Pacific sardine ( Sardinops sagax ). Based on the position of fish individuals along the head and chest regions of the ziphiid, the lack of digestion marks on fish remains and the homogeneous size of individuals, we propose that this assemblage results from the death of the whale (possibly via toxin poisoning) shortly after the capture of prey from a single school. Together with morphological data and the frequent discovery of fossil crown ziphiids in deep-sea deposits, this exceptional record supports the hypothesis that only more derived ziphiids were regular deep divers and that the extinction of epipelagic forms may coincide with the radiation of true dolphins.
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the most basal beaked whale ninoziphius platyrostris muizon 1983 clues on the evolutionary history of the family Ziphiidae cetacea odontoceti
Zoological Journal of the Linnean Society, 2013Co-Authors: Olivier Lambert, Christian De Muizon, Giovanni BianucciAbstract:Ninoziphius platyrostris, from the late Neogene of Peru, is one of the best-known fossil beaked whales (Odontoceti: Ziphiidae), with a holotype including the skull with ear bones, mandibles, teeth, and postcranial elements. Furthermore, based on several characters, including a complete functional upper and lower dentition, it is usually considered as one of the most archaic ziphiids. However, the poorly preserved dorsal portion of the holotype skull has led to unresolved phylogenetic relationships. With the addition of two newly prepared skulls from the same Peruvian locality we redescribed N. platyrostris. In the light of recent ziphiid discoveries, an emended diagnosis of the species is proposed here. In our cladistic analysis Ninoziphius is the most basal stem ziphiid. Newly observed or reassessed morphological traits allow functional and ecological considerations. The morphology of the oral apparatus suggests that Ninoziphius was less specialized for suction feeding than most extant ziphiids. Tooth wear in the holotype may indicate benthic feeding. Although the vertebral column of Ninoziphius corresponds to less developed locomotor abilities for deep dives, its cranial morphology does not provide definitive arguments for an echolocation system less efficient than in deep diving extant ziphiids. Finally, the phylogenetic tree produced was used to detail the evolutionary history of several major ziphiid features (dental reduction, development of mandibular tusks, and increased body size). © 2013 The Linnean Society of London
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a new beaked whale odontoceti Ziphiidae from the middle miocene of peru
Journal of Vertebrate Paleontology, 2009Co-Authors: Olivier Lambert, Giovanni Bianucci, Klaas PostAbstract:ABSTRACT On the basis of a partial odontocete (toothed whale) skeleton (complete skull with associated ear bones, mandible, teeth, hyoid bones, and cervical vertebrae) from the middle Miocene (ca. 14–12 Ma) levels of the Pisco Formation at Cerro los Quesos, Pisco-Ica desert, southern coast of Peru, a new genus and species of beaked whale (Ziphiidae), Nazcacetus urbinai, is described. This small ziphiid, the best documented fossil species to date, is characterized by a strong reduction of the upper and lower dentitions except for a pair of large apical mandibular teeth, a Tasmacetus-like vertex, a short mandibular symphysis, and the abrupt elevation of the dorsal margin of the mandible towards the coronoid process. A phylogenetic analysis indicates that Nazcacetus is a crown ziphiid, in a more crownward position than Berardiinae and Tasmacetus, but branching before the Hyperoodontinae and Ziphiinae lineages. Several morphological traits observed in Nazcacetus, including the reduction of teeth, the small te...
Olivier Lambert - One of the best experts on this subject based on the ideXlab platform.
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Yaquinacetus meadi, a new latest Oligocene–early Miocene dolphin (Cetacea, Odontoceti, SqualoZiphiidae, fam. nov.) from the Nye Mudstone (Oregon, U.S.A.)
2019Co-Authors: Olivier Lambert, Stephen J. Godfrey, Erich M. G. FitzgeraldAbstract:Represented by a nearly complete cranium with associated mandible, teeth, and vertebrae, Yaquinacetus meadi is a new genus and species of archaic homodont odontocete from the latest Oligocene–early Miocene (24–19.2 Ma) of Oregon, U.S.A. The new species is characterized by a moderately elongated rostrum bearing approximately 51 alveoli per tooth row and a knob-like, rectangular vertex. Together with Squaloziphius emlongi from the early Miocene of Washington State, Y. meadi constitutes a new odontocete family, SqualoZiphiidae, fam. nov., diagnosed by a unique combination of characters, including transversely wide dorsal opening of the mesorostral groove at base of rostrum, followed posteriorly by an abrupt narrowing; thickened lateral margin of the maxilla in the antorbital region making a long and laterally concave crest; and massive, anteroposteriorly and ventrally long postglenoid process of the squamosal. Although sharing with Ziphiidae the presence of transverse premaxillary crests on the vertex, SqualoZiphiidae differs in the pterygoid sinus fossa being shorter anteriorly and ventrally; the tubercule of the malleus being less reduced; and lacking a pair of enlarged alveoli for mandibular tusks. Our phylogenetic analysis confirms the sister-group relationship between S. emlongi and Y. meadi, either as late diverging stem odontocetes or as early crown odontocetes, but distant from Ziphiidae. These results confirm the northeastern Pacific as a center of diversification for several groups of archaic homodont odontocetes during the late Oligocene–early Miocene.
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neogene and quaternary fossil remains of beaked whales cetacea odontoceti Ziphiidae from deep sea deposits off crozet and kerguelen islands southern ocean
Geodiversitas, 2018Co-Authors: Olivier Lambert, Christian De Muizon, Guy Duhamel, Johannes Van Der PlichtAbstract:ABSTRACT Although a high number of extant beaked whale species (Cetacea, Odontoceti, Ziphiidae) live in the Southern Ocean and neighbouring areas, only little is known about the past occupation of the region by these highly specialized, deep diving and echolocating cetaceans. Recently, longline fishing activities along the seafloor at depths of 500–2000 m off the sub-antarctic Crozet and Kerguelen islands, Indian sector of Southern Ocean, resulted in the accessory “capture” of tens of ziphiid fossil cranial remains. Our description and comparison of the best-preserved and most diagnostic crania from this sample lead to the identification of more than eight species in at least seven genera: the hyperoodontines Africanacetus ceratopsis, Khoikhoicetus kergueleni n. sp., Hyperoodontinae indet. aff. Africanacetus, and Mesoplodon sp. aff. Mesoplodon layardii, the ziphiines Izikoziphius rossi and Ziphius sp., and the ziphiids indet. Nenga sp. aff. Nenga meganasalis and Xhosacetus hendeysi. Unsurprisingly, with a...
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a new early pliocene species of mesoplodon a calibration mark for the radiation of this species rich beaked whale genus
Journal of Vertebrate Paleontology, 2016Co-Authors: Olivier Lambert, Stephen LouwyeAbstract:ABSTRACTIncluding at least 15 extant species, the beaked whale genus Mesoplodon (Cetacea, Odontoceti, Ziphiidae) is by far the most species-rich cetacean genus. Such a high diversity reflects one or several pulses of radiation, most likely involving a sexual selection mechanism affecting shape, size, and position of mandibular tusks. However, the tempo of this diversification is currently poorly constrained due to the scarce fossil record. Based on the reassessment of five partial skulls discovered in Antwerp (north of Belgium), a new fossil species of the genus Mesoplodon, M. posti, sp. nov., is described. Only the second fossil species of the genus currently recognized, it is characterized (among other features) by: transverse sections of the rostrum higher than wide (a feature proposed to correspond to the presence of lower tusks more posterior than the apex of the mandibles); the presence of a basirostral groove at the rostrum base; pentagonal joined nasals; the posterior projection of the premaxilla ...
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no deep diving evidence of predation on epipelagic fish for a stem beaked whale from the late miocene of peru
Proceedings of The Royal Society B: Biological Sciences, 2015Co-Authors: Olivier Lambert, Mario Urbina, Claudio Di Celma, Klaas Post, Benjamin Ramassamy, Alberto Collareta, Walter Landini, Giovanni BianucciAbstract:Although modern beaked whales (Ziphiidae) are known to be highly specialized toothed whales that predominantly feed at great depths upon benthic and benthopelagic prey, only limited palaeontological data document this major ecological shift. We report on a ziphiid–fish assemblage from the Late Miocene of Peru that we interpret as the first direct evidence of a predator–prey relationship between a ziphiid and epipelagic fish. Preserved in a dolomite concretion, a skeleton of the stem ziphiid Messapicetus gregarius was discovered together with numerous skeletons of a clupeiform fish closely related to the epipelagic extant Pacific sardine ( Sardinops sagax ). Based on the position of fish individuals along the head and chest regions of the ziphiid, the lack of digestion marks on fish remains and the homogeneous size of individuals, we propose that this assemblage results from the death of the whale (possibly via toxin poisoning) shortly after the capture of prey from a single school. Together with morphological data and the frequent discovery of fossil crown ziphiids in deep-sea deposits, this exceptional record supports the hypothesis that only more derived ziphiids were regular deep divers and that the extinction of epipelagic forms may coincide with the radiation of true dolphins.
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the most basal beaked whale ninoziphius platyrostris muizon 1983 clues on the evolutionary history of the family Ziphiidae cetacea odontoceti
Zoological Journal of the Linnean Society, 2013Co-Authors: Olivier Lambert, Christian De Muizon, Giovanni BianucciAbstract:Ninoziphius platyrostris, from the late Neogene of Peru, is one of the best-known fossil beaked whales (Odontoceti: Ziphiidae), with a holotype including the skull with ear bones, mandibles, teeth, and postcranial elements. Furthermore, based on several characters, including a complete functional upper and lower dentition, it is usually considered as one of the most archaic ziphiids. However, the poorly preserved dorsal portion of the holotype skull has led to unresolved phylogenetic relationships. With the addition of two newly prepared skulls from the same Peruvian locality we redescribed N. platyrostris. In the light of recent ziphiid discoveries, an emended diagnosis of the species is proposed here. In our cladistic analysis Ninoziphius is the most basal stem ziphiid. Newly observed or reassessed morphological traits allow functional and ecological considerations. The morphology of the oral apparatus suggests that Ninoziphius was less specialized for suction feeding than most extant ziphiids. Tooth wear in the holotype may indicate benthic feeding. Although the vertebral column of Ninoziphius corresponds to less developed locomotor abilities for deep dives, its cranial morphology does not provide definitive arguments for an echolocation system less efficient than in deep diving extant ziphiids. Finally, the phylogenetic tree produced was used to detail the evolutionary history of several major ziphiid features (dental reduction, development of mandibular tusks, and increased body size). © 2013 The Linnean Society of London
Robin W. Baird - One of the best experts on this subject based on the ideXlab platform.
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site fidelity associations and movements of cuvier s ziphius cavirostris and blainville s mesoplodon densirostris beaked whales off the island of hawai i
Marine Mammal Science, 2007Co-Authors: Daniel J Mcsweeney, Robin W. Baird, Sabre D MahaffyAbstract:Although the Ziphiidae are the second-most speciose family of cetaceans, information on beaked whale species and populations has been limited by the difficulties in finding and approaching free-ranging individuals. Site fidelity, patterns of association, and movements of two species, Cuvier’s (Ziphius cavirostris) and Blainville’s (Mesoplodon densirostris) beaked whales, were assessed using a 21-yr photographic data set from the west coast of the island of Hawai‘i. Resightings of individuals of both species spanned 15 yr, suggesting long-term site fidelity to the area. Long-term resightings were documented primarily from adult females of both species. Group sizes for both species were small and most groups had only a single adult male present. For Blainville’s beaked whales, repeated associations between adult females and adult males were documented for all resightings of adult males over periods from 1 to 154 d. Among adult females, although repeated associations occurred up to 9 yr apart, individuals were seen separately in intervening years. Individuals
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diving behaviour of cuvier s ziphius cavirostris and blainville s mesoplodon densirostris beaked whales in hawai i
Canadian Journal of Zoology, 2006Co-Authors: Robin W. Baird, Daniel J Mcsweeney, Daniel L Webster, Allan D Ligon, Gregory S Schorr, Jay BarlowAbstract:Beaked whales (family Ziphiidae) are thought to be among the longest and deepest diving mammals, and some species appear to be prone to mass-strand in response to high-intensity sonar. We studied diving behaviour of Cuvier's ( Zi- phius cavirostris G. Cuvier, 1823) and Blainville's (Mesoplodon densirostris(Blainville, 1817)) beaked whales in Hawai- ian waters using suction-cup-attached time-depth recorders. Six whales, two Cuvier's and four Blainville's, were tagged and 41 h of dive data were collected. While Cuvier's beaked whales were found in significantly deeper water depths (me- dian depth = 2079 m) than Blainville's beaked whales (median depth = 922 m), several aspects of diving were similar be- tween the two species: (i) both regularly dove for 48-68 min to depths greater than 800 m (maximum 1408 m for Blainville's and 1450 m for Cuvier's); (ii) ascent rates for long/deep dives were substantially slower than descent rates, while for shorter dives there were no consistent differences; and (iii) both spent prolonged periods of time (66-155 min) in the upper 50 m of the water column. Based on time intervals between dives for the Cuvier's beaked whales, such long dives were likely aerobic, but both species appeared to prepare for long dives by spending extended periods of time near the surface. Resume ´ : Les baleines a bec (famille Ziphiidae) passent pour les mammiferes qui font les plongees les plus longues et les plus profondes et certaines especes sont portees as'echouer en groupe en reaction au sonar de forte intensite ´. Nous avons etudiele comportement de plongee des baleines abec de Cuvier (Ziphius cavirostris G. Cuvier, 1823) et de Blainville
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deep diving behaviour of the northern bottlenose whale hyperoodon ampullatus cetacea Ziphiidae
Proceedings of the Royal Society of London. Series B: Biological Sciences, 1999Co-Authors: Sascha K Hooker, Robin W. BairdAbstract:Using suction–cup attached time–depth recorder/VHF radio tags, we have obtained the first diving data on northern bottlenose whales ( Hyperoodon ampullatus ), the first such data on any species within the family Ziphiidae. Two deployments in 1997 on northern bottlenose whales in a submarine canyon off Nova Scotia demonstrated their exceptional diving ability, with dives approximately every 80 min to over 800 m (maximum 1453 m), and up to 70 min in duration. Sonar traces of non–tagged, diving bottlenose whales in 1996 and 1997 suggest that such deep dives are not unusual. This combined evidence leads us to hypothesize that these whales may make greater use of deep portions of the water column than any other mammal so far studied. Many of the recorded dives of the tagged animals were to, or close to, the sea floor, consistent with benthic or bathypelagic foraging. A lack of correlation between dive times and surface intervals suggests that the dives were predominately aerobic.
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Deep–diving behaviour of the northern bottlenose whale, Hyperoodon ampullatus (Cetacea: Ziphiidae)
Proceedings of The Royal Society B: Biological Sciences, 1999Co-Authors: Sascha K Hooker, Robin W. BairdAbstract:Using suction–cup attached time–depth recorder/VHF radio tags, we have obtained the first diving data on northern bottlenose whales ( Hyperoodon ampullatus ), the first such data on any species within the family Ziphiidae. Two deployments in 1997 on northern bottlenose whales in a submarine canyon off Nova Scotia demonstrated their exceptional diving ability, with dives approximately every 80 min to over 800 m (maximum 1453 m), and up to 70 min in duration. Sonar traces of non–tagged, diving bottlenose whales in 1996 and 1997 suggest that such deep dives are not unusual. This combined evidence leads us to hypothesize that these whales may make greater use of deep portions of the water column than any other mammal so far studied. Many of the recorded dives of the tagged animals were to, or close to, the sea floor, consistent with benthic or bathypelagic foraging. A lack of correlation between dive times and surface intervals suggests that the dives were predominately aerobic.
Sascha K Hooker - One of the best experts on this subject based on the ideXlab platform.
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Using Energetic Models to Investigate the Survival and Reproduction of Beaked Whales (family Ziphiidae)
2013Co-Authors: Leslie F. New, Sascha K Hooker, David J. Moretti, Daniel P. Costa, Samantha E. SimmonsAbstract:Mass stranding of several species of beaked whales (family Ziphiidae) associated with exposure to anthropogenic sounds has raised concern for the conservation of these species. However, little is known about the species’ life histories, prey or habitat requirements. Without this knowledge, it becomes difficult to assess the effects of anthropogenic sound, since there is no way to determine whether the disturbance is impacting the species’ physical or environmental requirements. Here we take a bioenergetics approach to address this gap in our knowledge, as the elusive, deep-diving nature of beaked whales has made it hard to study these effects directly. We develop a model for Ziphiidae linking feeding energetics to the species’ requirements for survival and reproduction, since these life history traits would be the most likely to be impacted by non-lethal disturbances. Our models suggest that beaked whale reproduction requires energy dense prey, and that poor resource availability would lead to an extension of the inter-calving interval. Further, given current information, it seems that some beaked whale species require relatively high quality habitat in order to meet their requirements for survival and reproduction. As a result, even a small non-lethal disturbance that results in displacement of whales from preferred habitats could potentially impact a population if a significant proportion of that population was affected. We explored the impact of varying ecological parameters and model assumptions on survival and reproduction, and find that calf and fetus survival appear more readily affected than the survival of adult females.
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Using Energetic Models to Investigate the Survival and Reproduction of Beaked Whales (family Ziphiidae)
2012Co-Authors: Leslie F. New, Sascha K Hooker, David J. Moretti, Daniel P. Costa, Samantha E. SimmonsAbstract:Mass stranding of several species of beaked whales (family Ziphiidae) associated with exposure to anthropogenic sounds has raised concern for the conservation of these species. However, little is known about the species ’ life histories, prey or habitat requirements. Without this knowledge, it becomes difficult to assess the effects of anthropogenic sound, since there is no way to determine whether the disturbance is impacting the species ’ physical or environmental requirements. Here we take a bioenergetics approach to address this gap in our knowledge, as the elusive, deep-diving nature of beaked whales has made it hard to study these effects directly. We develop a model for Ziphiidae linking feeding energetics to the species’ requirements for survival and reproduction, since these life history traits would be the most likely to be impacted by non-lethal disturbances. Our models suggest that beaked whale reproduction requires energy dense prey, and that poor resource availability would lead to an extension of the inter-calving interval. Further, given current information, it seems that some beaked whale species require relatively high quality habitat in order to meet their requirements for survival and reproduction. As a result, even a small non-lethal disturbance that results in displacement of whales from preferred habitats could potentially impact a population if a significant proportion of that population was affected. We explored the impact of varying ecological parameters and model assumptions on survival and reproduction, and find that calf and fetus surviva
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deep diving behaviour of the northern bottlenose whale hyperoodon ampullatus cetacea Ziphiidae
Proceedings of the Royal Society of London. Series B: Biological Sciences, 1999Co-Authors: Sascha K Hooker, Robin W. BairdAbstract:Using suction–cup attached time–depth recorder/VHF radio tags, we have obtained the first diving data on northern bottlenose whales ( Hyperoodon ampullatus ), the first such data on any species within the family Ziphiidae. Two deployments in 1997 on northern bottlenose whales in a submarine canyon off Nova Scotia demonstrated their exceptional diving ability, with dives approximately every 80 min to over 800 m (maximum 1453 m), and up to 70 min in duration. Sonar traces of non–tagged, diving bottlenose whales in 1996 and 1997 suggest that such deep dives are not unusual. This combined evidence leads us to hypothesize that these whales may make greater use of deep portions of the water column than any other mammal so far studied. Many of the recorded dives of the tagged animals were to, or close to, the sea floor, consistent with benthic or bathypelagic foraging. A lack of correlation between dive times and surface intervals suggests that the dives were predominately aerobic.
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Deep–diving behaviour of the northern bottlenose whale, Hyperoodon ampullatus (Cetacea: Ziphiidae)
Proceedings of The Royal Society B: Biological Sciences, 1999Co-Authors: Sascha K Hooker, Robin W. BairdAbstract:Using suction–cup attached time–depth recorder/VHF radio tags, we have obtained the first diving data on northern bottlenose whales ( Hyperoodon ampullatus ), the first such data on any species within the family Ziphiidae. Two deployments in 1997 on northern bottlenose whales in a submarine canyon off Nova Scotia demonstrated their exceptional diving ability, with dives approximately every 80 min to over 800 m (maximum 1453 m), and up to 70 min in duration. Sonar traces of non–tagged, diving bottlenose whales in 1996 and 1997 suggest that such deep dives are not unusual. This combined evidence leads us to hypothesize that these whales may make greater use of deep portions of the water column than any other mammal so far studied. Many of the recorded dives of the tagged animals were to, or close to, the sea floor, consistent with benthic or bathypelagic foraging. A lack of correlation between dive times and surface intervals suggests that the dives were predominately aerobic.
Geographic Range - One of the best experts on this subject based on the ideXlab platform.
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December 2012 GERVAIS ' BEAKED WHALE (Mesoplodon europaeus): Northern Gulf of Mexico Stock
2013Co-Authors: Stock Definition, Geographic RangeAbstract:Three species of Mesoplodon are known to occur in the Gulf of Mexico, based on stranding or sighting data (Hansen et al. 1995; Würsig et al. 2000). These are Blainville's beaked whale (M. densirostris), Gervais ' beaked whale (M. europaeus) and Sowerby's beaked whale (M. bidens). Sowerby’s beaked whale in the Gulf of Mexico is considered extralimital because there is only 1 known stranding of this species (Bonde and O’Shea 1989) and because it normally occurs in northern temperate waters of the North Atlantic (Mead 1989). Identification of Mesoplodon to species in the Gulf of Mexico is very difficult, and in many cases, Mesoplodon and Cuvier’s beaked whale (Ziphius cavirostris) cannot be distinguished; therefore, sightings of beaked whales (Family Ziphiidae) are identified as Mesoplodon sp., Cuvier’s beaked whale, or unidentified Ziphiidae. Gervais ’ beaked whales appear to be widely but sparsely distributed in temperate and tropical waters of the world’s oceans (Leatherwood et al. 1976; Leatherwood and Reeves 1983). Strandings have occurred along th
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December 2005 GERVAIS ' BEAKED WHALE (Mesoplodon europaeus): Northern Gulf of Mexico Stock
2013Co-Authors: Stock Definition, Geographic RangeAbstract:Three species of Mesoplodon are known to occur in the Gulf of Mexico, based on stranding or sighting data (Hansen et al. 1995; Würsig et al. 2000). These are Blainville's beaked whale (M. densirostris), Gervais ' beaked whale (M. europaeus), and Sowerby's beaked whale (M. bidens). Sowerby’s beaked whale in the Gulf of Mexico is considered extralimital because there is only 1 known stranding of this species (Bonde and O’Shea 1989) and because it normally occurs in northern temperate waters of the North Atlantic (Mead 1989). Identification of Mesoplodon to species in the Gulf of Mexico is very difficult, and in many cases, Mesoplodon and Cuvier’s beaked whale (Ziphius cavirostris) cannot be distinguished; therefore, sightings of beaked whales (Family Ziphiidae) are identified as Mesoplodon sp., Cuvier’s beaked whale, or unidentified Ziphiidae. Gervais ’ beaked whales appear to be widely but sparsely distributed in temperate and tropical waters of the world’s oceans (Leatherwood et al. 1976; Leatherwood and Reeves 1983). Strandings have occurred along the northwestern Atlantic coast from Florida to Nova Scotia (Schmidly 1981), and there have been 16 documented strandings in the Gulf of Mexico (Würsig et al. 2000). Beaked whales were seen in all seasons during GulfCet aerial surveys of the norther
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TX
2005Co-Authors: Northern Gulf, Stock Definition, Mexico Stock, Geographic RangeAbstract:Three species of Mesoplodon are known to occur in the Gulf of Mexico, based on stranding or sighting data (Hansen et al. 1995; Würsig et al. 2000). These are Blainville's beaked whale (M. densirostris), Gervais ' beaked whale (M. europaeus) and Sowerby's beaked whale (M. bidens). Sowerby’s beaked whale in the Gulf of Mexico is considered extralimital because there is only 1 known stranding of this species (Bonde and O’Shea 1989) and because it normally occurs in northern temperate waters of the North Atlantic (Mead 1989). Identification of Mesoplodon to species in the Gulf of Mexico is very difficult, and in many cases, Mesoplodon and Cuvier’s beaked whale (Ziphius cavirostris) cannot be distinguished; therefore, sightings of beaked whales (Family Ziphiidae) are identified as Mesoplodon sp., Cuvier’s beaked whale, or unidentified Ziphiidae. Blainville’s beaked whales appear to be widely but sparsely distributed in temperate and tropical waters of the world’s oceans (Leatherwood et al. 1976; Leatherwood and Reeves 1983). Strandings have occurred along the northwestern Atlantic coast from Florida to Nova Scotia (Schmidly 1981), and there have been 4 documented strandings and 2 sightings of this species in the northern Gulf of Mexico (Hansen et al. 1995; Würsig et al. 2000). Beaked whales were seen in all seasons during GulfCet aerial surveys of the northern Gulf of Mexico from 1992 to 1998 (Hansen et al. 1996; Mullin and Hoggard 2000). The Gulf of Mexico population is provisionally being considered a separate stock for management purposes, although there is currently no information to differentiate this stock from the Atlantic Ocean stock(s). Additional morphological, genetic and/or behavioral data are needed to provide further information on stock delineation
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BLAINVILLE’S BEAKED WHALE (Mesoplodon densirostris): Northern Gulf of Mexico Stock
2005Co-Authors: Stock Definition, Geographic RangeAbstract:Three species of Mesoplodon are known to occur in the Gulf of Mexico, based on stranding or sighting data (Hansen et al. 1995; Würsig et al. 2000). These are Blainville's beaked whale (M. densirostris), Gervais ' beaked whale (M. europaeus) and Sowerby's beaked whale (M. bidens). Sowerby’s beaked whale in the Gulf of Mexico is considered extralimital because there is only 1 known stranding of this species (Bonde and O’Shea 1989) and because it normally occurs in northern temperate waters of the North Atlantic (Mead 1989). Identification of Mesoplodon to species in the Gulf of Mexico is very difficult, and in many cases, Mesoplodon and Cuvier’s beaked whale (Ziphius cavirostris) cannot be distinguished; therefore, sightings of beaked whales (Family Ziphiidae) are identified as Mesoplodon sp., Cuvier’s beaked whale, or unidentified Ziphiidae. Blainville’s beaked whales appear to be widely but sparsely distributed in temperate and tropical waters of the world’s oceans (Leatherwood et al. 1976; Leatherwood and Reeves 1983). Strandings have occurred along the northwestern Atlantic coast from Florida to Nova Scotia (Schmidly 1981), and there have been 4 documented strandings and 2 sightings of this species in the northern Gulf of Mexico (Hansen et al. 1995; Würsig et al. 2000). Beaked whales were seen in all seasons during GulfCet aerial surveys of the northern Gulf of Mexico from 1992 to 1998 (Hansen et al. 1996; Mullin and Hoggard 2000). The Gulf of Mexico population is provisionally being considered a separate stock for management purposes, although there is currently no information to differentiate this stock from the Atlantic Ocean stock(s). Additional morphological, genetic and/or behavioral data are needed to provide further information on stock delineation
