Search

Between June 1987 and March 1988, bottlenose dolphins (Tursiops truncatus Montagu 1821) along the US Atlantic coast experienced an epizootic. Monthly interquartile ranges of strandings during the epizootic were used to propose the Coastal Migratory Stock (CMS) of bottlenose dolphins (Scott et al., 1988). To date, the hypothesised CMS remains poorly understood. The goal of this study was to use a 25-year database to compare stranding patterns during the epizootic to those before (1972-1986) and after (1989-1997) the event. These comparisons reveal that monthly interquartile ranges during the epizootic are dissimilar to those before and after the event. The frequency distribution of total monthly strandings during the epizootic is also significantly different from those observed outside the event. Seasonal stranding patterns from 1989-1997 suggest more complex movements of dolphins along the US Atlantic coast than those of a single group ranging seasonally from Florida to New Jersey. In winter, for example, when the current model for the CMS predicts dolphin distributions concentrated in central Florida, the highest number of strandings occurred in North Carolina. Thus, these comparative analyses suggest that the pattern observed during the epizootic was anomalous, and not representative of stranding distributions for any other time period of the study. During the 15 years before the epizootic, and the nine years following, there was no clear picture of ‘migration’ of mortality along the coast. This study demonstrates how long-term, systematic collection of strandings data can be useful in testing hypotheses regarding the complex stock structure of coastal bottlenose dolphins. This knowledge will greatly enhance the ability to conserve and manage these animals as they recover from historic (i.e. directed takes and epizootic) and current sources of mortality.

More than 100 species of large odontocete cetaceans (i.e., families Ziphiidae, Physeteridae, and Kogiidae) have been described since our binomial nomenclatorial system was initiated by Carl Linnaeus in 1758. Only a fraction of these are currently recognized as valid species. The taxonomic revisions that are being recommended by recent and ongoing studies within this group require a detailed understanding of their nomenclatural history. We here review all 114 nominal species of extant beaked and sperm whales. Of these, 27 species are currently considered valid, 6 are nomina dubia, 10 are nomina nuda, and the rest (71) are junior synonyms. In addition, we provide several appendices that attempt to settle the controversy over the name of the sperm whale (Physeter macrocephalus), provide biographies of the main authors of names, give a glossary of terms, and summarize information on the status of type specimens. Because beaked whales are still so poorly known, there are likely to be future splits and descriptions of new species and/or subspecies. This paper is intended to assist in sorting out nomenclature in such taxonomic cases.

This work was supported by ONR grants N000141613017 to E.L.C. and N.A. and N00014-18-1-2808 to C.S.B.; funds from the NMNH Rebecca G. Mead and James G. Mead Marine Mammal Endowment, NSF (USA) grant no. DEB-1457735 to M.S.S., P.A.M. and J.G.; Brothers Hartmann Foundation grant no. AB28148 to M.T.O.; NMFS, BOEM, and USA Navy funding to D.Ch. under the Atlantic Marine Assessment Program for Protected Species. M.L.M. was funded under the Marie Skłodowska-Curie grant agreement no 801199; E.L.C. by a Rutherford Discovery Fellowship from the Royal Society of New Zealand Te Apārangi. Irish Whale and Dolphin Group Cetacean Stranding scheme is part-funded by the National Parks and Wildlife Service. The deep sea has been described as the last major ecological frontier, as much of its biodiversity is yet to be discovered and described. Beaked whales (ziphiids) are among the most visible inhabitants of the deep sea, due to their large size and worldwide distribution, and their taxonomic diversity and much about their natural history remain poorly understood. We combine genomic and morphometric analyses to reveal a new Southern Hemisphere ziphiid species, Ramari's beaked whale, Mesoplodon eueu, whose name is linked to the Indigenous peoples of the lands from which the species holotype and paratypes were recovered. Mitogenome and ddRAD-derived phylogenies demonstrate reciprocally monophyletic divergence between M. eueu and True's beaked whale (M. mirus) from the North Atlantic, with which it was previously subsumed. Morphometric analyses of skulls also distinguish the two species. A time-calibrated mitogenome phylogeny and analysis of two nuclear genomes indicate divergence began circa 2 million years ago (Ma), with geneflow ceasing 0.35–0.55 Ma. This is an example of how deep sea biodiversity can be unravelled through increasing international collaboration and genome sequencing of archival specimens. Our consultation and involvement with Indigenous peoples offers a model for broadening the cultural scope of the scientific naming process. Publisher PDF

SummaryElusive species are challenging to study and conserve because basic elements of their biology may be unknown. Specimens of opportunity provide a means of collecting information on these species and may be critical for elusive species’ conservation. We used snowball sampling to identify Sowerby’s beaked whale (Mesoplodon bidens) specimens in museums and research institutions. Snowball sampling proved highly effective: we located 180 specimens from 24 institutions in North America and Europe, 62 of which were not listed in online collections databases, resulting in the largest collated dataset for this species. Analysis of these data resulted in several new findings for this species, including significant morphological variation between specimens from different collection regions, suggesting the presence of previously unidentified population structuring in this species. These data provide critical information regarding this species and demonstrate the effectiveness of specimens of opportunity for elusive species research and conservation. We recommend other researchers consider snowball sampling when designing research projects utilizing specimens of opportunity. Our results demonstrate the usefulness of snowball sampling and specimens of opportunity to elusive species research and conservation, and the methods of our study can be readily adapted for other species.

In 1815, the naturalist Constantine Samuel Rafinesque (1783–1840) previewed three new species of cetaceans – Delphinus dalippus, Physeter urganantus and Oxypterus mongitori – that he intended to describe from Sicily based on illustrations in Antonino Mongitore's published work Della Sicilia ricercata nelle cose più memorabili (1742–1743). Although formal descriptions of the three species were never published, Rafinesque's reference to Mongitore's illustrations made the names available by “indication”. The names, nonetheless, fell into obscurity, most likely a result of contemporary taxonomists' lack of access to Mongitore's work. Rafinesque's names remain relevant to the history of cetacean taxonomy, although they are no longer applicable. Moreover, the animals associated with these names add to the historical record of whale strandings in the Mediterranean. For these reasons, we studied the illustrations Rafinesque indicated for his cetaceans and reviewed Mongitore's accompanying text, which together provide sufficient distinctive characters that two of the three animals can be confidently identified with modern species, namely the sperm whale, Physeter catodon Linnaeus, 1758 , and the false killer whale, Pseudorca crassidens (Owen, 1846). Had Rafinesque's name D. dalippus been recognized for what it was, it would have had priority over P. crassidens as the earliest scientific name for the false killer whale.

In 1815, the naturalist Constantine S. Rafinesque described a new species of cetacean, Balena gastrytis, from Sicily, based on a whale that stranded on Carini beach near Palermo. In comparing the characteristics of his new whale with known species, Rafinesque also took the opportunity to name a new genus, Cetoptera, to replace Balaenoptera Lacépède, 1804 . Unfortunately, few of Rafinesque's contemporaries saw his article, which appeared in Il Portafoglio, a local journal that he published and distributed. The journal remains rare, and awareness of the whale remains minimal, despite its relevance to cetacean taxonomy and understanding of whale diversity and distribution in the Mediterranean. We describe the circumstances of the stranding of the Sicilian whale and provide Rafinesque's original description of the whale, as well as an evaluation of its reported characteristics and its current identity.

Two types of Berardius are recognised by local whalers in Hokkaido, Japan. The first is the ordinary Baird’s beaked whale, B. bairdii, whereas the other is much smaller and entirely black. Previous molecular phylogenetic analyses revealed that the black type is one recognisable taxonomic unit within the Berardius clade but is distinct from the two known Berardius species. To determine the characteristics of the black type, we summarised external morphology and skull osteometric data obtained from four individuals, which included three individuals from Hokkaido and one additional individual from the United States National Museum of Natural History collection. The whales differed from all of their congeners by having the following unique characters: a substantially smaller body size of physically mature individuals, proportionately shorter beak, and darker body colour. Thus, we conclude that the whales are a third Berardius species.

Underwater human activities and anthropogenic noise in our oceans may be a major source of habitat degradation for marine life. This issue was highlighted by the opening of the United States Eastern Seaboard for seismic oil and gas exploration in 2014, which generated massive media coverage and widespread concern that seismic surveys could kill or deafen whales. We discovered 11 new specimens of fractured and healed cetacean ear bones, out of a survey of 2127 specimens housed in museum collections. This rare condition has been previously reported only in two specimens of blue whales (Balaenoptera musculus) from the early 1900s, summarized by Fraser & Purves (1953). All of our new specimens are represented by species for which this condition had never been reported previously, including both baleen and toothed whales. The baleen whale specimens (Balaenoptera physalus, Balaenoptera borealis, Balaenoptera acutorostrata) were collected during Canadian commercial whaling operations in the Atlantic Ocean in the 1970s; the specimens include ear bones with well‐healed fractures, demonstrating that baleen whales are capable of overcoming traumatic injury to the ears. The toothed whale specimens (Delphinus sp., Berardius bairdii) were found dead on beaches in 1972 and 2001, respectively, with less remodeled fractures. Thus, ear injuries may be more lethal to the echolocating toothed whales, which rely on hearing for navigation and foraging. We explore several hypotheses regarding how these injuries could have occurred, and conclude that the most parsimonious explanations appear to be both direct and indirect effects of lytic processes from disease or calcium depletion, or damage from external pressure waves. Although further research is required to confirm whether the fractures resulted from natural or human‐induced events, this study underscores the importance of museum collections and the work of stranding networks in understanding the potential effects of modern human activities on marine mammal health.

The erupted tusk of the narwhal exhibits sensory ability. The hypothesized sensory pathway begins with ocean water entering through cementum channels to a network of patent dentinal tubules extending from the dentinocementum junction to the inner pulpal wall. Circumpulpal sensory structures then signal pulpal nerves terminating near the base of the tusk. The maxillary division of the fifth cranial nerve then transmits this sensory information to the brain. This sensory pathway was first described in published results of patent dentinal tubules, and evidence from dissection of tusk nerve connection via the maxillary division of the fifth cranial nerve to the brain. New evidence presented here indicates that the patent dentinal tubules communicate with open channels through a porous cementum from the ocean environment. The ability of pulpal tissue to react to external stimuli is supported by immunohistochemical detection of neuronal markers in the pulp and gene expression of pulpal sensory nerve tissue. Final confirmation of sensory ability is demonstrated by significant changes in heart rate when alternating solutions of high-salt and fresh water are exposed to the external tusk surface. Additional supporting information for function includes new observations of dentinal tubule networks evident in unerupted tusks, female erupted tusks, and vestigial teeth. New findings of sexual foraging divergence documented by stable isotope and fatty acid results add to the discussion of the functional significance of the narwhal tusk. The combined evidence suggests multiple tusk functions may have driven the tooth organ system's evolutionary development and persistence. Anat Rec, 297:599–617, 2014. © 2014 Wiley Periodicals, Inc.

We present genetic and morphological evidence supporting the recognition of a previously synonymized species of Mesoplodon beaked whale in the tropical Indo-Pacific, Mesoplodon hotaula. Although the new species is closely-related to the rare ginkgo-toothed beaked whale M. ginkgodens, we show that these two lineages can be differentiated by maternally (mitochondrial DNA), biparentally (autosomal), and paternally (Y chromosome) inherited DNA sequences, as well as by morphological features. The reciprocal monophyly of the mtDNA genealogies and the largely parapatric distribution of these lineages is consistent with reproductive isolation. The new lineage is currently known from at least seven specimens: Sri Lanka (1), Gilbert Islands, Republic of Kiribati (1+), Palmyra Atoll, Northern Line Islands, U.S.A. (3), Maldives (1), and Seychelles (1). The type specimen (Sri Lanka) was described as a new species, M. hotaula, in 1963, but later synonymized with M. ginkgodens. This discovery brings the total number of Mesoplodon species to 15, making it, by far, the most speciose yet least known genus of cetaceans.

Narwhal tusks, although well described and characterized within publications, are clouded by contradictory references, which refer to them as both incisors and canines. Vestigial teeth are briefly mentioned in the scientific literature with limited descriptions and no image renderings. This study first examines narwhal maxillary osteoanatomy to determine whether the erupted tusks are best described as incisiform or caniniform teeth. The study also offers evidence to support the evolutionary obsolescence of the vestigial teeth through anatomic, morphologic, and histologic descriptions. Examination of 131 skull samples, including 110 museum skull specimens and 21 harvested skulls, revealed the erupted tusks surrounded by maxillary bone over the entire length of their bone socket insertion, and are thus more accurately termed caniniform or canine teeth. The anatomy, morphology, and development of vestigial teeth in five skull samples are more fully described and documented. Vestigial tooth samples included 14 embedded pairs or individual teeth that were partially exposed or removed from the maxillary bone. Their location was posterior, ventral, and lateral to the tusks, although male vestigial teeth often exfoliate in the mouth lodging between the palatal tissue and underlying maxillary bone. Their myriad morphologies, sizes, and eruption patterns suggest that these teeth are no longer guided by function but rather by random germ cell differentiation and may eventually cease expression entirely. The conclusions reached are that the narwhal tusks are the expression of canine teeth and that vestigial teeth have no apparent functional characteristics and are following a pattern consistent with evolutionary obsolescence.

Steno bredanensis (Cuvier in Lesson, 1828) is a small odontocete commonly called the rough-toothed dolphin. A slender, gray dolphin with a slightly darker cape, this species is most easily distinguished from other small delphinids by a gradually sloping forehead and a long rostrum. It is the only species in the genus Steno. Despite reports of sightings or stranded specimens from all tropical and subtropical oceans, the species is thought to typically occur in low abundance. The conservation status of S. bredanensis is poorly known.

This study's objective was to investigate mandibular fractures in 50 short-finned pilot whales, Globicephala macrorhynchus, from two mass strandings. Based on current theories that this species is sexually dimorphic and polygynous, hypotheses were: (1) males should suffer more frequent or more substantial mandibular fractures than should females, and (2) fracture occurrence should increase with male reproductive maturity and potential correlates of maturity, such as age and length. Fractures were described and correlated with physical characteristics to infer possible explanations for injuries. Mandibular fractures were surprisingly common in males and females, being found in more than half of the animals examined (27/50, or 54% overall; 17/36 or 47% of females and 10/14 or 71 % of males). Length was the only correlate of fracture presence; the proportion of animals showing evidence of fracture increased with length. These results offer some support to initial hypotheses, but there must be another set of consequences that contribute to mandibular fractures in females. A combination of intra- and interspecific interactions and life history characteristics may be responsible for fractures. Further research from a larger sample of this and other cetacean species are suggested to help elucidate both the causes and implications of mandibular fractures.

Mass strandings of beaked whales (family Ziphiidae) have been reported in the scientific literature since 1874. Several recent mass strandings of beaked whales have been reported to coincide with naval active sonar exercises. To obtain the broadest assessment of surface ship naval active sonar operations coinciding with beaked whale mass strandings, a list of global naval training and antisubmarine warfare exercises was compiled from openly available sources and compared by location and time with historic stranding records. This list includes activities of navies of other nations but emphasizes recent U.S. activities because of what is available in publicly accessible sources. Of 136 beaked whale mass stranding events reported from 1874 to 2004, 126 occurred between 1950 and 2004, after the introduction and implementation of modern, high-power mid-frequency active sonar (MFAS). Of these 126 reports, only two reported details on the use, timing, and location of sonar in relation to mass strandings. Ten other mass strandings coincided in space and time with naval exercises that may have included MFAS. An additional 27 mass stranding events occurred near a naval base or ship but with no direct evidence of sonar use. The remaining 87 mass strandings have no evidence for a link with any naval activity. Six of these 87 cases have evidence for a cause unrelated to active sonar. The large number of global naval activities annually with potential MFAS usage in comparison to the relative rarity of mass stranding events suggests that most MFAS operations take place with no reported stranding events and that for an MFAS operation to cause a mass stranding of beaked whales, a confluence of several risk factors is probably required. Identification of these risk factors will help in the development of measures to reduce the risk of sonar-related strandings.