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Christiane Weirauch - One of the best experts on this subject based on the ideXlab platform.
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evolution of the assassin s arms insights from a phylogeny of combined transcriptomic and ribosomal dna data heteroptera reduvioidea
Scientific Reports, 2016Co-Authors: Junxia Zhang, Eric R L Gordon, Michael Forthman, Wei Song Hwang, Kim Walden, Daniel R Swanson, Kevin P Johnson, Rudolf Meier, Christiane WeirauchAbstract:Assassin bugs (Reduvioidea) are one of the most diverse (>7,000 spp.) lineages of predatory animals and have evolved an astounding diversity of Raptorial leg modifications for handling prey. The evolution of these modifications is not well understood due to the lack of a robust phylogeny, especially at deeper nodes. We here utilize refined data from transcriptomes (370 loci) to stabilize the backbone phylogeny of Reduvioidea, revealing the position of major clades (e.g., the Chagas disease vectors Triatominae). Analyses combining transcriptomic and Sanger-sequencing datasets result in the first well-resolved phylogeny of Reduvioidea. Despite amounts of missing data, the transcriptomic loci resolve deeper nodes while the targeted ribosomal genes anchor taxa at shallower nodes, both with high support. This phylogeny reveals patterns of Raptorial leg evolution across major leg types. Hairy attachment structures (fossula spongiosa), present in the ancestor of Reduvioidea, were lost multiple times within the clade. In contrast to prior hypotheses, this loss is not directly correlated with the evolution of alternative Raptorial leg types. Our results suggest that prey type, predatory behavior, salivary toxicity, and morphological adaptations pose intricate and interrelated factors influencing the evolution of this diverse group of predators.
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Evolution of the assassin’s arms: insights from a phylogeny of combined transcriptomic and ribosomal DNA data (Heteroptera: Reduvioidea)
Scientific reports, 2016Co-Authors: Junxia Zhang, Eric R L Gordon, Michael Forthman, Wei Song Hwang, Daniel R Swanson, Kevin P Johnson, Rudolf Meier, Kim K.o. Walden, Christiane WeirauchAbstract:Assassin bugs (Reduvioidea) are one of the most diverse (>7,000 spp.) lineages of predatory animals and have evolved an astounding diversity of Raptorial leg modifications for handling prey. The evolution of these modifications is not well understood due to the lack of a robust phylogeny, especially at deeper nodes. We here utilize refined data from transcriptomes (370 loci) to stabilize the backbone phylogeny of Reduvioidea, revealing the position of major clades (e.g., the Chagas disease vectors Triatominae). Analyses combining transcriptomic and Sanger-sequencing datasets result in the first well-resolved phylogeny of Reduvioidea. Despite amounts of missing data, the transcriptomic loci resolve deeper nodes while the targeted ribosomal genes anchor taxa at shallower nodes, both with high support. This phylogeny reveals patterns of Raptorial leg evolution across major leg types. Hairy attachment structures (fossula spongiosa), present in the ancestor of Reduvioidea, were lost multiple times within the clade. In contrast to prior hypotheses, this loss is not directly correlated with the evolution of alternative Raptorial leg types. Our results suggest that prey type, predatory behavior, salivary toxicity, and morphological adaptations pose intricate and interrelated factors influencing the evolution of this diverse group of predators.
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on the evolution of Raptorial legs an insect example hemiptera reduviidae phymatinae
Cladistics, 2011Co-Authors: Christiane Weirauch, Dimitri Forero, Dawid H. JacobsAbstract:The presence of chelate and subchelate fore legs in Phymatinae (Hemiptera: Reduviidae), or ambush bugs, provides a unique opportunity to study the evolution of different types of Raptorial legs in a closely related group of arthropods. Themonocorini have simple, possibly Raptorial legs, Phymatini and Macrocephalini distinct subchelate fore legs, and the charismatic Carcinocorini are the only insects with a chelate fore leg apart from female dryinid Chysidoidea (Hymenoptera). Relationships between the four phymatine tribes are here analyzed in a cladistic framework thus permitting testable hypotheses on the evolution of Raptorial legs. The presented analysis of phymatine tribal level relationships is based on a dataset comprising 11 species of Phymatinae and 54 non-phymatine Reduviidae and Heteroptera. The molecular data set consists of ∼3500 MAFFT aligned bases of 16S, 28S D2–D3, and 18S ribosomal genes. Parsimony and maximum likelihood analyses resulted in identical topologies for the ingroup with the relationships Themonocorini + (Phymatini + (Carcinocorini + Macrocephalini)) receiving high support values. Eleven morphological characters, eight of them derived from fore leg morphology, were optimized on the parsimony analysis. These optimizations indicate that the ancestral ambush bug had a simple Raptorial leg; that size reduction of the tarsus, enlargement of the femur, curvature of the fore tibia, armature of tibia and femur with rows of tiny tubercles that allow for gripping of a prey insect, and the large process on the ventral surface of the femur arose in the common ancestor of Carcinocorini + Macrocephalini + Phymatini. The chelate leg in Carcinocorini is likely derived from a subchelate precursor similar to the one seen in recent Macrocephalini and may have evolved through elongation of the ventral, proximal portion of the fore femur and modification of the median process to form part of the digitus fixus. © The Willi Hennig Society 2010.
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On the evolution of Raptorial legs – an insect example (Hemiptera: Reduviidae: Phymatinae)
Cladistics, 2011Co-Authors: Christiane Weirauch, Dimitri Forero, Dawid H. JacobsAbstract:The presence of chelate and subchelate fore legs in Phymatinae (Hemiptera: Reduviidae), or ambush bugs, provides a unique opportunity to study the evolution of different types of Raptorial legs in a closely related group of arthropods. Themonocorini have simple, possibly Raptorial legs, Phymatini and Macrocephalini distinct subchelate fore legs, and the charismatic Carcinocorini are the only insects with a chelate fore leg apart from female dryinid Chysidoidea (Hymenoptera). Relationships between the four phymatine tribes are here analyzed in a cladistic framework thus permitting testable hypotheses on the evolution of Raptorial legs. The presented analysis of phymatine tribal level relationships is based on a dataset comprising 11 species of Phymatinae and 54 non-phymatine Reduviidae and Heteroptera. The molecular data set consists of ∼3500 MAFFT aligned bases of 16S, 28S D2–D3, and 18S ribosomal genes. Parsimony and maximum likelihood analyses resulted in identical topologies for the ingroup with the relationships Themonocorini + (Phymatini + (Carcinocorini + Macrocephalini)) receiving high support values. Eleven morphological characters, eight of them derived from fore leg morphology, were optimized on the parsimony analysis. These optimizations indicate that the ancestral ambush bug had a simple Raptorial leg; that size reduction of the tarsus, enlargement of the femur, curvature of the fore tibia, armature of tibia and femur with rows of tiny tubercles that allow for gripping of a prey insect, and the large process on the ventral surface of the femur arose in the common ancestor of Carcinocorini + Macrocephalini + Phymatini. The chelate leg in Carcinocorini is likely derived from a subchelate precursor similar to the one seen in recent Macrocephalini and may have evolved through elongation of the ventral, proximal portion of the fore femur and modification of the median process to form part of the digitus fixus. © The Willi Hennig Society 2010.
Junxia Zhang - One of the best experts on this subject based on the ideXlab platform.
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evolution of the assassin s arms insights from a phylogeny of combined transcriptomic and ribosomal dna data heteroptera reduvioidea
Scientific Reports, 2016Co-Authors: Junxia Zhang, Eric R L Gordon, Michael Forthman, Wei Song Hwang, Kim Walden, Daniel R Swanson, Kevin P Johnson, Rudolf Meier, Christiane WeirauchAbstract:Assassin bugs (Reduvioidea) are one of the most diverse (>7,000 spp.) lineages of predatory animals and have evolved an astounding diversity of Raptorial leg modifications for handling prey. The evolution of these modifications is not well understood due to the lack of a robust phylogeny, especially at deeper nodes. We here utilize refined data from transcriptomes (370 loci) to stabilize the backbone phylogeny of Reduvioidea, revealing the position of major clades (e.g., the Chagas disease vectors Triatominae). Analyses combining transcriptomic and Sanger-sequencing datasets result in the first well-resolved phylogeny of Reduvioidea. Despite amounts of missing data, the transcriptomic loci resolve deeper nodes while the targeted ribosomal genes anchor taxa at shallower nodes, both with high support. This phylogeny reveals patterns of Raptorial leg evolution across major leg types. Hairy attachment structures (fossula spongiosa), present in the ancestor of Reduvioidea, were lost multiple times within the clade. In contrast to prior hypotheses, this loss is not directly correlated with the evolution of alternative Raptorial leg types. Our results suggest that prey type, predatory behavior, salivary toxicity, and morphological adaptations pose intricate and interrelated factors influencing the evolution of this diverse group of predators.
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Evolution of the assassin’s arms: insights from a phylogeny of combined transcriptomic and ribosomal DNA data (Heteroptera: Reduvioidea)
Scientific reports, 2016Co-Authors: Junxia Zhang, Eric R L Gordon, Michael Forthman, Wei Song Hwang, Daniel R Swanson, Kevin P Johnson, Rudolf Meier, Kim K.o. Walden, Christiane WeirauchAbstract:Assassin bugs (Reduvioidea) are one of the most diverse (>7,000 spp.) lineages of predatory animals and have evolved an astounding diversity of Raptorial leg modifications for handling prey. The evolution of these modifications is not well understood due to the lack of a robust phylogeny, especially at deeper nodes. We here utilize refined data from transcriptomes (370 loci) to stabilize the backbone phylogeny of Reduvioidea, revealing the position of major clades (e.g., the Chagas disease vectors Triatominae). Analyses combining transcriptomic and Sanger-sequencing datasets result in the first well-resolved phylogeny of Reduvioidea. Despite amounts of missing data, the transcriptomic loci resolve deeper nodes while the targeted ribosomal genes anchor taxa at shallower nodes, both with high support. This phylogeny reveals patterns of Raptorial leg evolution across major leg types. Hairy attachment structures (fossula spongiosa), present in the ancestor of Reduvioidea, were lost multiple times within the clade. In contrast to prior hypotheses, this loss is not directly correlated with the evolution of alternative Raptorial leg types. Our results suggest that prey type, predatory behavior, salivary toxicity, and morphological adaptations pose intricate and interrelated factors influencing the evolution of this diverse group of predators.
Felix G Marx - One of the best experts on this subject based on the ideXlab platform.
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gigantism precedes filter feeding in baleen whale evolution
Current Biology, 2018Co-Authors: Ewan R Fordyce, Felix G MarxAbstract:Summary Baleen whales (Mysticeti) are the largest animals on Earth, thanks to their ability to filter huge volumes of small prey from seawater. Mysticetes appeared during the Late Eocene, but evidence of their early evolution remains both sparse and controversial [1, 2], with several models competing to explain the origin of baleen-based bulk feeding [3–6]. Here, we describe a virtually complete skull of Llanocetus denticrenatus , the second-oldest (ca. 34 Ma) mysticete known. The new material represents the same individual as the type and only specimen, a fragmentary mandible. Phylogenetic analysis groups Llanocetus with the oldest mysticete, Mystacodon selenensis [2], into the basal family Llanocetidae. Llanocetus is gigantic (body length ∼8 m) compared to other early mysticetes [7–9]. The broad rostrum has sharp, widely spaced teeth with marked dental abrasion and attrition, suggesting biting and occlusal shearing. As in extant mysticetes, the palate bears many sulci, commonly interpreted as osteological correlates of baleen [3]. Unexpectedly, these sulci converge on the upper alveoli, suggesting a peri-dental blood supply to well-developed gums, rather than to inter-alveolar racks of baleen. We interpret Llanocetus as a Raptorial or suction feeder, revealing that whales evolved gigantism well before the emergence of filter feeding. Rather than driving the origin of mysticetes, baleen and filtering most likely only arose after an initial phase of suction-assisted Raptorial feeding [2, 4, 5]. This scenario differs strikingly from that proposed for odontocetes, whose defining adaptation—echolocation—was present even in their earliest representatives [10].
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Ancient whales did not filter feed with their teeth
Biology letters, 2017Co-Authors: David P. Hocking, Felix G Marx, Erich M. G. Fitzgerald, Alistair R. EvansAbstract:The origin of baleen whales (Mysticeti), the largest animals on Earth, is closely tied to their signature filter-feeding strategy. Unlike their modern relatives, archaic whales possessed a well-developed, heterodont adult dentition. How these teeth were used, and what role their function and subsequent loss played in the emergence of filter feeding, is an enduring mystery. In particular, it has been suggested that elaborate tooth crowns may have enabled stem mysticetes to filter with their postcanine teeth in a manner analogous to living crabeater and leopard seals, thereby facilitating the transition to baleen-assisted filtering. Here we show that the teeth of archaic mysticetes are as sharp as those of terrestrial carnivorans, Raptorial pinnipeds and archaeocetes, and thus were capable of capturing and processing prey. By contrast, the postcanine teeth of leopard and crabeater seals are markedly blunter, and clearly unsuited to Raptorial feeding. Our results suggest that mysticetes never passed through a tooth-based filtration phase, and that the use of teeth and baleen in early whales was not functionally connected. Continued selection for tooth sharpness in archaic mysticetes is best explained by a feeding strategy that included both biting and suction, similar to that of most living pinnipeds and, probably, early toothed whales (Odontoceti).
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Supplementary Table S8 from Ancient whales did not filter feed with their teeth
2017Co-Authors: David P. Hocking, Felix G Marx, Erich M. G. Fitzgerald, Alistair R. EvansAbstract:The origin of baleen whales (Mysticeti), the largest animals on Earth, is closely tied to their signature filter-feeding strategy. Unlike their modern relatives, archaic whales possessed a well-developed, heterodont adult dentition. How these teeth were used, and what role their function and subsequent loss played in the emergence of filter feeding, is an enduring mystery. In particular, it has been suggested that elaborate tooth crowns may have enabled stem mysticetes to filter with their postcanine teeth in a manner analogous to living crabeater and leopard seals, thereby facilitating the transition to baleen-assisted filtering. Here we show that the teeth of archaic mysticetes are as sharp as those of terrestrial carnivorans, Raptorial pinnipeds and archaeocetes, and thus were capable of capturing and processing prey. By contrast, the postcanine teeth of leopard and crabeater seals are markedly blunter, and clearly unsuited to Raptorial feeding. Our results suggest that mysticetes never passed through a tooth-based filtration phase, and that the use of teeth and baleen in early whales was not functionally connected. Continued selection for tooth sharpness in archaic mysticetes is best explained by a feeding strategy that included both biting and suction, similar to that of most living pinnipeds and, probably, early toothed whales (Odontoceti)
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a new early oligocene toothed baleen whale mysticeti aetiocetidae from western north america one of the oldest and the smallest
Royal Society Open Science, 2015Co-Authors: Felix G Marx, Ewan R Fordyce, Chenghsiu TsaiAbstract:Archaic toothed mysticetes represent the evolutionary transition from Raptorial to bulk filter feeding in baleen whales. Aetiocetids, in particular, preserve an intermediate morphological stage in which teeth functioned alongside a precursor of baleen, the hallmark of all modern mysticetes. To date, however, aetiocetids are almost exclusively Late Oligocene and coeval with both other toothed mysticetes and fully fledged filter feeders. By contrast, reports of cetaceans from the Early Oligocene remain rare, leaving the origins of aetiocetids, and thus of baleen, largely in the dark. Here, we report a new aetiocetid, Fucaia buelli, from the earliest Oligocene (ca 33-31 Ma) of western North America. The new material narrows the temporal gap between aetiocetids and the oldest known mysticete, Llanocetus (ca 34 Ma). The specimen preserves abundant morphological detail relating to the phylogenetically informative ear bones (otherwise poorly documented in this family), the hyoid apparatus and much of the (heterodont) dentition. Fucaia comprises some of the smallest known mysticetes, comparable in size with the smallest odontocetes. Based on their phylogenetic relationships and dental and mandibular morphology, including tooth wear patterns, we propose that aetiocetids were suction-assisted Raptorial feeders and interpret this strategy as a crucial, intermediary step, enabling the transition from Raptorial to filter feeding. Following this line of argument, a combination of Raptorial and suction feeding would have been ancestral to all toothed mysticetes, and possibly even baleen whales as a whole.
Dawid H. Jacobs - One of the best experts on this subject based on the ideXlab platform.
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on the evolution of Raptorial legs an insect example hemiptera reduviidae phymatinae
Cladistics, 2011Co-Authors: Christiane Weirauch, Dimitri Forero, Dawid H. JacobsAbstract:The presence of chelate and subchelate fore legs in Phymatinae (Hemiptera: Reduviidae), or ambush bugs, provides a unique opportunity to study the evolution of different types of Raptorial legs in a closely related group of arthropods. Themonocorini have simple, possibly Raptorial legs, Phymatini and Macrocephalini distinct subchelate fore legs, and the charismatic Carcinocorini are the only insects with a chelate fore leg apart from female dryinid Chysidoidea (Hymenoptera). Relationships between the four phymatine tribes are here analyzed in a cladistic framework thus permitting testable hypotheses on the evolution of Raptorial legs. The presented analysis of phymatine tribal level relationships is based on a dataset comprising 11 species of Phymatinae and 54 non-phymatine Reduviidae and Heteroptera. The molecular data set consists of ∼3500 MAFFT aligned bases of 16S, 28S D2–D3, and 18S ribosomal genes. Parsimony and maximum likelihood analyses resulted in identical topologies for the ingroup with the relationships Themonocorini + (Phymatini + (Carcinocorini + Macrocephalini)) receiving high support values. Eleven morphological characters, eight of them derived from fore leg morphology, were optimized on the parsimony analysis. These optimizations indicate that the ancestral ambush bug had a simple Raptorial leg; that size reduction of the tarsus, enlargement of the femur, curvature of the fore tibia, armature of tibia and femur with rows of tiny tubercles that allow for gripping of a prey insect, and the large process on the ventral surface of the femur arose in the common ancestor of Carcinocorini + Macrocephalini + Phymatini. The chelate leg in Carcinocorini is likely derived from a subchelate precursor similar to the one seen in recent Macrocephalini and may have evolved through elongation of the ventral, proximal portion of the fore femur and modification of the median process to form part of the digitus fixus. © The Willi Hennig Society 2010.
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On the evolution of Raptorial legs – an insect example (Hemiptera: Reduviidae: Phymatinae)
Cladistics, 2011Co-Authors: Christiane Weirauch, Dimitri Forero, Dawid H. JacobsAbstract:The presence of chelate and subchelate fore legs in Phymatinae (Hemiptera: Reduviidae), or ambush bugs, provides a unique opportunity to study the evolution of different types of Raptorial legs in a closely related group of arthropods. Themonocorini have simple, possibly Raptorial legs, Phymatini and Macrocephalini distinct subchelate fore legs, and the charismatic Carcinocorini are the only insects with a chelate fore leg apart from female dryinid Chysidoidea (Hymenoptera). Relationships between the four phymatine tribes are here analyzed in a cladistic framework thus permitting testable hypotheses on the evolution of Raptorial legs. The presented analysis of phymatine tribal level relationships is based on a dataset comprising 11 species of Phymatinae and 54 non-phymatine Reduviidae and Heteroptera. The molecular data set consists of ∼3500 MAFFT aligned bases of 16S, 28S D2–D3, and 18S ribosomal genes. Parsimony and maximum likelihood analyses resulted in identical topologies for the ingroup with the relationships Themonocorini + (Phymatini + (Carcinocorini + Macrocephalini)) receiving high support values. Eleven morphological characters, eight of them derived from fore leg morphology, were optimized on the parsimony analysis. These optimizations indicate that the ancestral ambush bug had a simple Raptorial leg; that size reduction of the tarsus, enlargement of the femur, curvature of the fore tibia, armature of tibia and femur with rows of tiny tubercles that allow for gripping of a prey insect, and the large process on the ventral surface of the femur arose in the common ancestor of Carcinocorini + Macrocephalini + Phymatini. The chelate leg in Carcinocorini is likely derived from a subchelate precursor similar to the one seen in recent Macrocephalini and may have evolved through elongation of the ventral, proximal portion of the fore femur and modification of the median process to form part of the digitus fixus. © The Willi Hennig Society 2010.
Jelle W F Reumer - One of the best experts on this subject based on the ideXlab platform.
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the giant bite of a new Raptorial sperm whale from the miocene epoch of peru
Nature, 2010Co-Authors: Olivier Lambert, Rodolfo Salasgismondi, Christian De Muizon, Giovanni Bianucci, Mario Urbina, Klaas Post, Jelle W F ReumerAbstract:Modern sperm whales have the biggest bite of any tetrapod, but their teeth are relatively small and restricted to the lower jaw, and they feed by suction. The discovery of large teeth in the fossil record had suggested, however, that predatory sperm whales once existed, similar in habit to today's killer whales, but much larger. Suggestion becomes reality with the discovery of the fossil teeth and jaws of a predatory sperm whale from the Middle Miocene of Peru, almost as large as a modern sperm whale but with a three-metre head and jaws full of teeth. This beast was probably able to prey upon large marine vertebrates — perhaps the medium-sized baleen whales abundant around 12 million years ago — in a way similar to the modern killer whale. Modern sperm whales have relatively small teeth and feed by suction, but the discovery of large teeth in the fossil record suggests that Raptorial sperm whales once existed. Here the authors report the discovery of the teeth and jaws of a fossil Raptorial sperm whale from the Middle Miocene of Peru, almost as large as a modern sperm whale but with a three-metre head and jaws full of teeth, some 36cm long. The modern giant sperm whale Physeter macrocephalus, one of the largest known predators, preys upon cephalopods at great depths1,2. Lacking a functional upper dentition, it relies on suction for catching its prey3; in contrast, several smaller Miocene sperm whales (Physeteroidea) have been interpreted as Raptorial (versus suction) feeders4,5, analogous to the modern killer whale Orcinus orca. Whereas very large physeteroid teeth have been discovered in various Miocene localities, associated diagnostic cranial remains have not been found so far6,7,8. Here we report the discovery of a new giant sperm whale from the Middle Miocene of Peru (approximately 12–13 million years ago), Leviathan melvillei, described on the basis of a skull with teeth and mandible. With a 3-m-long head, very large upper and lower teeth (maximum diameter and length of 12 cm and greater than 36 cm, respectively), robust jaws and a temporal fossa considerably larger than in Physeter, this stem physeteroid represents one of the largest Raptorial predators and, to our knowledge, the biggest tetrapod bite ever found. The appearance of gigantic Raptorial sperm whales in the fossil record coincides with a phase of diversification and size-range increase of the baleen-bearing mysticetes in the Miocene. We propose that Leviathan fed mostly on high-energy content medium-size baleen whales. As a top predator, together with the contemporaneous giant shark Carcharocles megalodon, it probably had a profound impact on the structuring of Miocene marine communities. The development of a vast supracranial basin in Leviathan, extending on the rostrum as in Physeter, might indicate the presence of an enlarged spermaceti organ in the former that is not associated with deep diving or obligatory suction feeding.
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The giant bite of a new Raptorial sperm whale from the Miocene epoch of Peru
Nature, 2010Co-Authors: Olivier Lambert, Christian De Muizon, Giovanni Bianucci, Mario Urbina, Klaas Post, Rodolfo Salas-gismondi, Jelle W F ReumerAbstract:The modern giant sperm whale Physeter macrocephalus, one of the largest known predators, preys upon cephalopods at great depths. Lacking a functional upper dentition, it relies on suction for catching its prey; in contrast, several smaller Miocene sperm whales (Physeteroidea) have been interpreted as Raptorial (versus suction) feeders, analogous to the modern killer whale Orcinus orca. Whereas very large physeteroid teeth have been discovered in various Miocene localities, associated diagnostic cranial remains have not been found so far. Here we report the discovery of a new giant sperm whale from the Middle Miocene of Peru (approximately 12-13 million years ago), Leviathan melvillei, described on the basis of a skull with teeth and mandible. With a 3-m-long head, very large upper and lower teeth (maximum diameter and length of 12 cm and greater than 36 cm, respectively), robust jaws and a temporal fossa considerably larger than in Physeter, this stem physeteroid represents one of the largest Raptorial predators and, to our knowledge, the biggest tetrapod bite ever found. The appearance of gigantic Raptorial sperm whales in the fossil record coincides with a phase of diversification and size-range increase of the baleen-bearing mysticetes in the Miocene. We propose that Leviathan fed mostly on high-energy content medium-size baleen whales. As a top predator, together with the contemporaneous giant shark Carcharocles megalodon, it probably had a profound impact on the structuring of Miocene marine communities. The development of a vast supracranial basin in Leviathan, extending on the rostrum as in Physeter, might indicate the presence of an enlarged spermaceti organ in the former that is not associated with deep diving or obligatory suction feeding.
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ThegiantbiteofanewRaptorialspermwhalefromthe Miocene epoch of Peru
2010Co-Authors: Olivier Lambert, Christian De Muizon, Giovanni Bianucci, Mario Urbina, Klaas Post, Rodolfo Salas-gismondi, Jelle W F ReumerAbstract:. Here we report the discovery of anewgiantspermwhalefromtheMiddleMioceneofPeru(approxi-mately12–13millionyearsago),Leviathanmelvillei,describedonthebasisofaskullwithteethandmandible.Witha3-m-longhead,very large upper and lower teeth (maximum diameter and lengthof 12cm and greater than 36cm, respectively), robust jaws and atemporal fossa considerably larger than in Physeter, this stemphyseteroid represents one of the largest Raptorial predatorsand, to our knowledge, the biggest tetrapod bite ever found. Theappearance of gigantic Raptorial sperm whales in the fossil recordcoincideswithaphaseofdiversificationandsize-rangeincreaseofthe baleen-bearing mysticetes in the Miocene. We propose thatLeviathan fedmostly onhigh-energy content medium-size baleenwhales. As a top predator, together with the contemporaneousgiant shark Carcharocles megalodon, it probably had a profoundimpact on the structuring of Miocene marine communities. Thedevelopment of a vast supracranial basin in Leviathan, extendingon the rostrum as in Physeter, might indicate the presence of anenlargedspermacetiorganintheformerthatisnotassociatedwithdeep diving or obligatory suction feeding.With adult males reaching a body length of 18.3m, the modernsperm whale Physeter macrocephalus is one of the largest macro-predators ever found. It preys primarily on squid, which it usuallyhuntsatgreatdepths
