Encyclopedia of Marine Mammals || Museums and Collections
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Museums and Collections 747
these bones and all of the hind limb musculature were lost in the extant forms.
Hind limbs are well developed in the pinnipeds. Phocidae and Odobenidae use their hind limbs in aquatic locomotion, making adduction and abduction movements with an inverted foot. Phocidae do not use their hind limbs to support the body while on land. Otariidae trail their hind limbs during swimming, but use them during locomotion on land. Odobenidae also support their body with their hind limbs while on land.
In the phocids, the hind limb exors (e.g., the hamstrings) are reduced, whereas the extensors are supported by changed insertion of the adductors and obturator externus, which also serve in extension ( Fig. 4 ). Muscles below the knee are present in all pinnipeds, but those crossing the heel are stronger in phocids than in otariids.
See Also the Following Articles Cetacean Prenatal Development Skeletal Anatomy Skull Anatomy
References Domning , D. P. ( 1978 ). The myology of the Amazonian manatee,
Trichechus inunguis (Natterer)(Mammalia, Sirenia). Acta Amazon. 8 ( Suppl. 2 ), 1 80.
Howell , A. B. ( 1930 ). Aquatic Mammals, Their Adaptations to Life in the Water . C.C. Thomas , Baltimore.
Pabst , D. A. ( 1993 ). Intramuscular morphology and tendon geometry of the epaxial swimming muscles of dolphins. J. Zool. Lond. 230, 159176.
Purves , P. E., and Pilleri , G. E. ( 1983 ). Echolocation in Whales and Dolphins . Academic Press , London.
Slijper, E. J. ( 1936 ). Die Cetaceen, vergleichend-anatomisch und systematisch . Cap. Zool. 6 and 7, 1590.
Slijper, E. J. ( 1962 ). Whales . Basic Books , New York .
Museums and Collections
JOHN E. HEYNING AND JAMES G. MEAD
The integrative approach to studying biology is similar to constructing a jigsaw puzzleeach discipline and data set contribute in a meaningful way to understand the whole. Individual pieces may contribute more or less to the picture, but nonetheless all pieces are important. In biology, each discipline contributes its own unique set of pieces to the puzzle of life. Research in museums has historically focused on specimen-oriented disciplines and thus has contributed to these suites of puzzle pieces. Specimens are potential sources of data for the disciplines of systematics, paleontology, morphology, histology, genetics, pathology, life history, parasitology, toxicology, and biochemistry. In addition, museums serve as important forums of informal learning for the visitors that peruse the exhibits or engage in an educational program.
I. Biodiversity and Systematics Perhaps the most fundamental among the specimen-oriented
disciplines is the study of biodiversity, the dening of species and
populations within species. Most marine mammalogists working within museums in the nineteenth and early twentieth centuries spent their hours primarily describing new species from the vast array of specimens unloaded from some recent voyage of exploration so characteristic of that time. For instance, from the numerous marine mammal specimens collected by the Southern Hemisphere expeditions of the HMS Erebus and Terror during the years 18391843, John Gray of the British Museum (Natural History) described numerous new species, including the Ross seal (Ommatophoca rossii), the crabeater seal (Lobodon carcinophaga), the pygmy right whale (Caperea marginata), and the Chilean dolphin (Cephalorhynchus eutropia ). While the heyday of prolic new species description peaked a century ago, the need for the ongoing study remains very relevant today. Several new species (or resurrected old species) have been de ned within recent years, and most populations are just now being understood.
The classical approach of using morphology to de ne species continues to be relevant. However, analyses of molecular genetic data provide us with additional new tools to help de ne populations, species, and the relationship among species. Exemplary of this is the recent discovery of a new species of beaked whale. In the mid-1970s, several strandings occurred of a small species of beaked whale along a restricted section of southern California coastline. Because these specimens morphologically resembled the Southern Hemisphere species Mesoplodon hectori, scientists tentatively assigned these California animals to that taxon. A graduate student from New Zealand investigating beaked whale phylogeny sampled the DNA from these specimens along with many others held in museums. To her astonishment, these California specimens clustered nowhere near specimens of M. hectori from the Southern Hemisphere (Dalebout et al., 1998 ), hence providing evidence that they represented a new species.
Determining the evolutionary relationships, or phylogeny, among this diversity of species, both living and extinct, is the study of systematics. Systematics provides an evolutionary framework that becomes the foundation for the comparable biological approach. Phylogenies can be constructed using a variety of data sets, morphological, molecular, and fossilsall of which reside primarily within museums. Hence, M researchers today can infer past events from phylogenetic reconstructions of evolutionary relationships. Most modern systematists use a philosophical approach called cladistics. The basic tenets of cladistics are quite simple: organisms are deemed to be related based on shared derived characters called synapomorphies. Derived characters are dened as having arisen in the common ancestor of the taxa and subsequently passed onto their descendant taxa.
Museums have a long-term commitment to house specimens for research. Thus, material collected in the 1700s and 1800s is still available for scientic inquiry today. For many species, it is only through the accumulation of specimens and data over several decades, even over a century that we can obtain the sample sizes needed to begin to understand even the basic biology of these species. For systematic studies, it is crucial to examine a large series of specimens ( Fig. 1 ). To dene species or populations, one must rst know the limits of variationindividual, ontogenetic, sexual dimorphism to ascribe that the observed variation is due to limited genetic exchange.
II. Morphology How can a blue whale engulf up to 70 tons of water? Why does
not a narwhal break its tusk? How can a dolphin cool its testes so that spermatogenesis can occur? All these questions require the detailed examination of anatomical structures. This in turn requires that some
748 Museums and Collections
Figure 1 Museum workers collec a series of pilot whale specimens (Globicephala macrorhynchus). Series such as these allow biologists to dene species and to understand populations within species. Dening these biological units is crucial to conservation biology among other disciplines.
specimens are readily available. Some studies are limited to hard parts and can be answered by examining osteological material. However, studies of soft anatomy require that these structures be preserved. For most organisms, storage of the whole beast can be accomplished easily by plunking the specimen into a jar of formalin and/or alcohol. Preservation for future study of a good-sized dolphin, let alone a whale, presents far more of a logistical challenge. As the immense specimens typically need to be dissected without preservation, the task can be demanding, as these large, oil-laden mammals produce a
M rich organic bouquet as they decompose. Fortunately, there is now a renaissance of morphological work requiring innovative ways of preserving and studying cetacean anatomy.
III. History of Museum Research The rst large collections of marine mammals had their genesis in
the grand museums of Europe. Baron von Cuvier amassed and published on a very important collection in the early 1800s, which now resides in the Museum National dHistoire Naturelle in Paris. By the mid-1800s, the British Museum of Natural History (now the Natural History Museum, London) had built major collections as the British Empire explored the world. Two of the preeminent marine mammalogists of this era, William Henry Flower and John Edward Gray, increased our knowledge considerably by studying the specimens within this venerable museum. Aside from the collections amassed from expeditions, museums in Britain had a distinct advantage for growing their collections. In 1324, stranded whales and dolphins were declared Royal Fishe and therefore property of the Crown. The original intent of this decree was to ensure that an economically valuable stranded fresh whale would enhance the coffers of the government. An unforeseen benet was that the majority of strandings were of the economically non-valuable uneatable variety and therefore available for government supported museums. Hence the rst stranding program began (Fraser, 1974). This original decree and subsequent museum-oriented mindset was passed along to the then
British colonies. These former colonies now have museums with major collections including those in Australia, New Zealand, South Africa, and the United States.
Marine mammals as museum specimens are difcult to acquire, store, and maintain. As a result, there are very few large collections for researchers to use. Of the largest collection of land mammals, well over one dozen have more than 100,000 specimens. The majority of specimens in these collections are the taxonomically diverse and numerically abundant rodents and bats. In striking contrast, less than a dozen or so museums have collections of marine mammals numbering over a mere 1000 or so. These include the National Museum of Natural History (Smithsonian), Washington DC, USA; Natural History Museum of Los Angeles County, California, USA; National Science Museum, Tokyo, Japan; The Natural History Museum, London, UK; National Museum of New Zealand (Te Papa), Wellington; American Museum of Natural History, New York, USA; California Academy of Sciences, San Francisco, California, USA; South Australian Museum, Adelaide; Museum National dHistoire Naturelle, Paris, France; and South African Museum, Cape Town.
For a specimen to be of greatest utility for answering questions, it needs to have as much associated data with it as possible. Such archives provide context for the additional data collected by scientists. Originally, museum curators collected only skulls or skeletons along with occasional sketches of the living beast. Early in this century, following the lead set by the systematic collection of data from whaling stations, museum workers began documenting more data from each specimen. As the number of questions regarding marine mammal biology have increased concurrent with new analytical tools to address these questions, far more is being collected. Now it is not uncommon to collect the complete skeleton, frozen tissues, measurements, uid-preserved tissues, photographs, and notes.
IV. Public Display Over the past century and a half, museums have served an
increasing role as important centers for the public to learn about the natural world. Accurately mounted exhibits can convey great biological detail and grand-scale presence that would be difcult for the public to ever experience in the wild.
Many museums have also capitalized on the immensity of whales to create exhibit icons, most notably the model of a living blue whale (Balaenoptera musculus). In 1907, a model created from a 74.4-foot blue whale went on display at the American Museum of Natural History. Subsequently, the British Museum of Natural History (now called the Natural History Museum, London) erected its own blue whale model measuring some 88 feet in length. In the early 1960s, the Smithsonian Institution (Washington, DC) unveiled their 92-foot model ( Figure 2 ). Not to be outdone, the American Museum christened their new and anatomically more accurate 94-foot (28.7 m) model in 1969!
Museums hold collections in the public trust so that they are available to scholars in perpetuity. Thus they serve as guardians of the tangible evidence of time past and the archivists of our current natural heritage. In addition, museums serve as important centers at which the public can learn.
See Also the Following Articles History of Marine Mammal Research Systematics, Overview
Mysticetes, Evolution 749
Figure 2 The full-size model of a blue whale that was mounted at the National Museum of Natural History in Washington, DC.
References from the late Oligocene coincident with the radiation of toothed forms, but are not diverse until the Miocene. Although contested, it
Conover , A. ( 1996 ). The object at hand . Smithsonian 27( 7 ), 28, 30, 31 . is likely that most, if not all, archaic mysticetes possessed some formDalebout , M. L., van Helden , A., van Waerebeek , K., and Baker , C. S. of baleen in the upper jaw. This key lter feeding innovation permit( 1998 ). Molecular genetic identication of southern henmisphere
ted exploitation of a new niche and heralded the evolution of mod-beaked whales (Cetacea: Ziphiidae). Mol. Ecol. 7, 687694. ern baleen whales, the largest animals on Earth.Fraser, F. C. (1974). Report on Cetacea Stranded on the British Coasts
from 1948 to 1966. British Museum (Natural History), London. M II. Toothed Mysticetes
As currently understood, toothed mysticetes are grouped into four families: Llanocetidae, Mammalodontidae, and Janjucetidae from the Southern Ocean and Aetiocetidae, from the North Pacic. To date no toothed mysticetes are known from the Atlantic region. The retention of an adult dentition in toothed mysticetesMysticetes, Evolution is the primitive condition seen in basilosaurid archaeocetes and stem odontocetes. The degree of telescoping of the skull is alsoANNALISA BERTA AND THOMAS A. DEMR primitive with little interdigitation of rostral and cranial elements. Consequently, there is a long intertemporal exposure of the frontal
I. Introduction and parietal on the cranial vertex. In addition, the supraorbital proc
The fossil record of mysticete cetaceans is rapidly improving esses of the frontals retain an elevated position on the cranium, and and the origin and diversication of this highly specialized the external narial opening ( blowhole ) is only midway between mammalian group is coming into focus. Crown mysticetes the tip of the rostrum and the orbit. Derived features of toothed (i.e., extant baleen whales of the families Balaenidae, Neobalaenidae, and later mysticetes include transverse expansion of the descend-Balaenopteridae, and Eschrichtiidae) are edentulous as adults, but ing process of the maxilla to form an edentulous infraorbital plate, possess deciduous teeth that are resorbed prior to birth. This ontoge- loss of a bony mandibular symphysis, and thin lateral margins of the netic pattern reects an ancestral ontogeny in which fully formed maxillae. teeth were retained into adulthood. Archaic baleen whales include The geologically oldest purported mysticete is Llanocetus den-stem mysticetes, both toothed and toothless, that do not belong to ticrenatus from the late Eocene or early Oligocene of the Antarctic extant families. Toothed mysticetes rst evolved in the late Eocene Peninsula. Although only a portion of the mandible and an endocraor earliest Oligocene, diversied in the late Oligocene, and appear to nial cast have been described, the holotype also includes a nearly have been extinct before the Miocene began. They do not constitute complete skull and partial skeleton under study by Ewan Fordyce. a monophyletic group. Stem edentulous mysticetes are rst reported Despite its antiquity, Llanocetus was a large whale with a skull length
Museums and CollectionsI. Biodiversity and SystematicsII. MorphologyIII. History of Museum ResearchIV. Public DisplayReferences