94-397: See text Kogiidae is a family comprising at least two extant species of Cetacea, the pygmy ( Kogia breviceps) and dwarf ( K. sima) sperm whales . As their common names suggest, they somewhat resemble sperm whales , with squared heads and small lower jaws, but are much smaller, with much shorter skulls and more notable dorsal fins than sperm whales. Kogiids are also characterized by
188-481: A bagpipe -like structure to produce sound and an amplifying horn. Kogiidae have a modified colon which works as an " ink sac ", storing liquid red feces. They are able to release over three gallons of this fecal "ink" to confuse or discourage predators. Kogiidae are believed to be cosmopolitan species , inhabiting all oceans except polar waters, remaining between the 50° latitude lines. Two fossilized species of Kogia sp. were shown to exhibit sympatry , similar to
282-423: A mutation–selection balance . It is predicted that a viral quasispecies at a low but evolutionarily neutral and highly connected (that is, flat) region in the fitness landscape will outcompete a quasispecies located at a higher but narrower fitness peak in which the surrounding mutants are unfit, "the quasispecies effect" or the "survival of the flattest". There is no suggestion that a viral quasispecies resembles
376-515: A taxonomic rank of an organism, as well as a unit of biodiversity . Other ways of defining species include their karyotype , DNA sequence, morphology , behaviour, or ecological niche . In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses ) are given
470-542: A two-part name , called a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature , also sometimes in zoological nomenclature ). For example, Boa constrictor is one of the species of the genus Boa , with constrictor being the species' epithet. While the definitions given above may seem adequate at first glance, when looked at more closely they represent problematic species concepts. For example,
564-400: A "classical" method of determining species, such as with Linnaeus, early in evolutionary theory. However, different phenotypes are not necessarily different species (e.g. a four-winged Drosophila born to a two-winged mother is not a different species). Species named in this manner are called morphospecies . In the 1970s, Robert R. Sokal , Theodore J. Crovello and Peter Sneath proposed
658-422: A "false gill slit" behind their eyes. A number of extinct genera have been named. There is some amount of uncertainty over if Kogiidae belongs in the sperm whale family . Research still suggests a close relationship between Kogiidae and sperm whales using mitochondrial DNA , which supports Kogiidae as part of the sperm whale family. This relationship is supported by similarities of the anatomical structures in
752-424: A 'smallest clade' idea" (a phylogenetic species concept). Mishler and Wilkins and others concur with this approach, even though this would raise difficulties in biological nomenclature. Wilkins cited the ichthyologist Charles Tate Regan 's early 20th century remark that "a species is whatever a suitably qualified biologist chooses to call a species". Wilkins noted that the philosopher Philip Kitcher called this
846-428: A connected series of neighbouring populations, each of which can sexually interbreed with adjacent related populations, but for which there exist at least two "end" populations in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population. Such non-breeding, though genetically connected, "end" populations may co-exist in the same region thus closing
940-432: A different species from its ancestors. Viruses have enormous populations, are doubtfully living since they consist of little more than a string of DNA or RNA in a protein coat, and mutate rapidly. All of these factors make conventional species concepts largely inapplicable. A viral quasispecies is a group of genotypes related by similar mutations, competing within a highly mutagenic environment, and hence governed by
1034-508: A genetic boundary suitable for defining a species concept is present. DNA barcoding has been proposed as a way to distinguish species suitable even for non-specialists to use. One of the barcodes is a region of mitochondrial DNA within the gene for cytochrome c oxidase . A database, Barcode of Life Data System , contains DNA barcode sequences from over 190,000 species. However, scientists such as Rob DeSalle have expressed concern that classical taxonomy and DNA barcoding, which they consider
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#17328954033031128-465: A lineage should be divided into multiple chronospecies , or when populations have diverged to have enough distinct character states to be described as cladistic species. Species and higher taxa were seen from the time of Aristotle until the 18th century as categories that could be arranged in a hierarchy, the great chain of being . In the 19th century, biologists grasped that species could evolve given sufficient time. Charles Darwin 's 1859 book On
1222-492: A misnomer, need to be reconciled, as they delimit species differently. Genetic introgression mediated by endosymbionts and other vectors can further make barcodes ineffective in the identification of species. A phylogenetic or cladistic species is "the smallest aggregation of populations (sexual) or lineages (asexual) diagnosable by a unique combination of character states in comparable individuals (semaphoronts)". The empirical basis – observed character states – provides
1316-449: A particular species, including which genus (and higher taxa) it is placed in, is a hypothesis about the evolutionary relationships and distinguishability of that group of organisms. As further information comes to hand, the hypothesis may be corroborated or refuted. Sometimes, especially in the past when communication was more difficult, taxonomists working in isolation have given two distinct names to individual organisms later identified as
1410-400: A perfect model of life, it is still a useful tool to scientists and conservationists for studying life on Earth, regardless of the theoretical difficulties. If species were fixed and clearly distinct from one another, there would be no problem, but evolutionary processes cause species to change. This obliges taxonomists to decide, for example, when enough change has occurred to declare that
1504-477: A precise range and migration map difficult. They are believed to prefer off-shore waters, and are most frequently sighted in waters ranging from 400 to 1,000 m (1,300 to 3,300 ft) in depth, especially where upwelling water produces local concentrations of zooplankton and animal prey. Their status is usually described as rare, but occasional patches of higher-density strandings suggest they might be more common than previously estimated. The total population
1598-428: A sac in its intestines that contains a dark red fluid. The whale may expel this fluid when frightened, perhaps to confuse and disorient predators. Dwarf and pygmy sperm whales possess the shortest rostrum of current day cetaceans with a skull that is greatly asymmetrical. Pygmy sperm whales have from 50 to 55 vertebrae , and from 12 to 14 ribs on either side, although the latter are not necessarily symmetrical, and
1692-508: A sac in the lower portion of their intestinal tracts that contains up to 12 liters of dark reddish-brown fluid, which can be ejected to confuse or discourage potential predators. Pygmy sperm whales are found throughout the tropical and temperate waters of the Atlantic , Pacific , and Indian Oceans , and occasionally among colder waters such as off Russia. However, they are rarely sighted at sea, so most data come from stranded animals - making
1786-400: A short way of saying that something applies to many species within a genus, but not to all. If scientists mean that something applies to all species within a genus, they use the genus name without the specific name or epithet. The names of genera and species are usually printed in italics . However, abbreviations such as "sp." should not be italicised. When a species' identity is not clear,
1880-404: A specialist may use "cf." before the epithet to indicate that confirmation is required. The abbreviations "nr." (near) or "aff." (affine) may be used when the identity is unclear but when the species appears to be similar to the species mentioned after. With the rise of online databases, codes have been devised to provide identifiers for species that are already defined, including: The naming of
1974-523: A species as groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups. It has been argued that this definition is a natural consequence of the effect of sexual reproduction on the dynamics of natural selection. Mayr's use of the adjective "potentially" has been a point of debate; some interpretations exclude unusual or artificial matings that occur only in captivity, or that involve animals capable of mating but that do not normally do so in
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#17328954033032068-400: A species as determined by a taxonomist. A typological species is a group of organisms in which individuals conform to certain fixed properties (a type), so that even pre-literate people often recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens (such as longer or shorter tails) would differentiate the species. This method was used as
2162-488: A species. All species definitions assume that an organism acquires its genes from one or two parents very like the "daughter" organism, but that is not what happens in HGT. There is strong evidence of HGT between very dissimilar groups of prokaryotes , and at least occasionally between dissimilar groups of eukaryotes , including some crustaceans and echinoderms . The evolutionary biologist James Mallet concludes that there
2256-685: A species. Generally the term includes the unknown element of a distinct act of creation. Many authors have argued that a simple textbook definition, following Mayr's concept, works well for most multi-celled organisms , but breaks down in several situations: Species identification is made difficult by discordance between molecular and morphological investigations; these can be categorised as two types: (i) one morphology, multiple lineages (e.g. morphological convergence , cryptic species ) and (ii) one lineage, multiple morphologies (e.g. phenotypic plasticity , multiple life-cycle stages). In addition, horizontal gene transfer (HGT) makes it difficult to define
2350-519: A taxonomic decision at the discretion of cognizant specialists, is not governed by the Codes of Zoological or Botanical Nomenclature, in contrast to the PhyloCode , and contrary to what is done in several other fields, in which the definitions of technical terms, like geochronological units and geopolitical entities, are explicitly delimited. The nomenclatural codes that guide the naming of species, including
2444-506: A traditional biological species. The International Committee on Taxonomy of Viruses has since 1962 developed a universal taxonomic scheme for viruses; this has stabilised viral taxonomy. Most modern textbooks make use of Ernst Mayr 's 1942 definition, known as the Biological Species Concept as a basis for further discussion on the definition of species. It is also called a reproductive or isolation concept. This defines
2538-412: A tête courte "–small-headed sperm whale; further, the species name breviceps is Latin for "short-headed". In 1846, zoologist John Edward Gray erected the genus Kogia for the pygmy sperm whale as Kogia breviceps , and said it was intermediate between the sperm whale and dolphins. In 1871, mammalogist Theodore Gill assigned it and Euphysetes (now the dwarf sperm whale , Kogia sima ) to
2632-447: A variation on the morphological species concept, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms. It differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species
2726-515: A variety of reasons. Viruses are a special case, driven by a balance of mutation and selection , and can be treated as quasispecies . Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics . Early taxonomists such as Linnaeus had no option but to describe what they saw: this was later formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts,
2820-404: A whole is relatively similar. They have also been observed using echolocation to find their prey, and their hearing places them in the "Very High Frequency" group of cetaceans that can hear well above 100 kHz. Most observations of Kogia have come from individuals tangled in fishing line or stranded individuals. There is a commercial fishery for K. breviceps in parts of southeast Asia and
2914-438: Is "an entity composed of organisms which maintains its identity from other such entities through time and over space, and which has its own independent evolutionary fate and historical tendencies". This differs from the biological species concept in embodying persistence over time. Wiley and Mayden stated that they see the evolutionary species concept as "identical" to Willi Hennig 's species-as-lineages concept, and asserted that
Kogiidae - Misplaced Pages Continue
3008-408: Is a creamy, occasionally pinkish colour and the back and sides are a bluish grey; however, considerable intermixing occurs between the two colours. The shark-like head is large in comparison to body size, given an almost swollen appearance when viewed from the side. A whitish marking, often described as a "false gill", is seen behind each eye. The lower jaw is very small and slung low. The blowhole
3102-400: Is a group of sexually reproducing organisms that recognise one another as potential mates. Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms; no matter whether populations can hybridise successfully, they are still distinct cohesion species if
3196-458: Is a set of organisms adapted to a particular set of resources, called a niche, in the environment. According to this concept, populations form the discrete phenetic clusters that we recognise as species because the ecological and evolutionary processes controlling how resources are divided up tend to produce those clusters. A genetic species as defined by Robert Baker and Robert Bradley is a set of genetically isolated interbreeding populations. This
3290-431: Is another issue affecting this species, as it echolocates. Pygmy sperm whales have also repeatedly been found stranded with plastic in their stomachs. Species A species ( pl. : species) is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring , typically by sexual reproduction . It is the basic unit of classification and
3384-414: Is called speciation . Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book The Origin of Species . Speciation depends on a measure of reproductive isolation , a reduced gene flow. This occurs most easily in allopatric speciation, where populations are separated geographically and can diverge gradually as mutations accumulate. Reproductive isolation
3478-403: Is described formally, in a publication that assigns it a unique scientific name. The description typically provides means for identifying the new species, which may not be based solely on morphology (see cryptic species ), differentiating it from other previously described and related or confusable species and provides a validly published name (in botany) or an available name (in zoology) when
3572-400: Is displaced slightly to the left when viewed from above facing forward. The dorsal fin is very small and hooked; its size is considerably smaller than that of the dwarf sperm whale and may be used for diagnostic purposes. Like its giant relative, the sperm whale , the pygmy sperm whale has a spermaceti organ in its forehead (see sperm whale for a discussion of its purpose). It also has
3666-624: Is further included in the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia ( Western African Aquatic Mammals MoU ) and the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region ( Pacific Cetaceans MoU ). As not much is known about this species, as well as due to
3760-671: Is further weakened by the existence of microspecies , groups of organisms, including many plants, with very little genetic variability, usually forming species aggregates . For example, the dandelion Taraxacum officinale and the blackberry Rubus fruticosus are aggregates with many microspecies—perhaps 400 in the case of the blackberry and over 200 in the dandelion, complicated by hybridisation , apomixis and polyploidy , making gene flow between populations difficult to determine, and their taxonomy debatable. Species complexes occur in insects such as Heliconius butterflies, vertebrates such as Hypsiboas treefrogs, and fungi such as
3854-726: Is hard or even impossible to test. Later biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, and the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: (1) agamospecies for asexual organisms (2) biospecies for reproductively isolated sexual organisms (3) ecospecies based on ecological niches (4) evolutionary species based on lineage (5) genetic species based on gene pool (6) morphospecies based on form or phenotype and (7) taxonomic species,
Kogiidae - Misplaced Pages Continue
3948-416: Is needed to determine the real number of extant species of Kogiidae . ORDER ARTIODACTYLA Kogiid skulls are characterized by a very short rostrum , the smallest among extant cetaceans, as well as high levels of asymmetry, which is expected among odontocetes . Kogiid skulls have the most blunt mandible among extant cetaceans as well. Extant kogiidae also show relatively high encephalization quotient ,
4042-403: Is no easy way to tell whether related geographic or temporal forms belong to the same or different species. Species gaps can be verified only locally and at a point of time. One is forced to admit that Darwin's insight is correct: any local reality or integrity of species is greatly reduced over large geographic ranges and time periods. The botanist Brent Mishler argued that the species concept
4136-468: Is not valid, notably because gene flux decreases gradually rather than in discrete steps, which hampers objective delimitation of species. Indeed, complex and unstable patterns of gene flux have been observed in cichlid teleosts of the East African Great Lakes . Wilkins argued that "if we were being true to evolution and the consequent phylogenetic approach to taxa, we should replace it with
4230-586: Is similar to Mayr's Biological Species Concept, but stresses genetic rather than reproductive isolation. In the 21st century, a genetic species could be established by comparing DNA sequences. Earlier, other methods were available, such as comparing karyotypes (sets of chromosomes ) and allozymes ( enzyme variants). An evolutionarily significant unit (ESU) or "wildlife species" is a population of organisms considered distinct for purposes of conservation. In palaeontology , with only comparative anatomy (morphology) and histology from fossils as evidence,
4324-594: Is threatened by hybridisation, but this can be selected against once a pair of populations have incompatible alleles of the same gene, as described in the Bateson–Dobzhansky–Muller model . A different mechanism, phyletic speciation, involves one lineage gradually changing over time into a new and distinct form (a chronospecies ), without increasing the number of resultant species. Horizontal gene transfer between organisms of different species, either through hybridisation , antigenic shift , or reassortment ,
4418-560: Is unknown. Fossils identified as belonging to K. breviceps have been recovered from Miocene deposits in Italy, Japan, and southern Africa. Pygmy sperm whales have never been hunted on a wide scale. Land-based whalers have hunted them from Indonesia , Japan , and the Lesser Antilles . This species was impacted by whaling in the 18th and 19th centuries, as sperm whales were especially sought after by whalers for their sperm oil, produced by
4512-523: The ICZN for animals and the ICN for plants, do not make rules for defining the boundaries of the species. Research can change the boundaries, also known as circumscription, based on new evidence. Species may then need to be distinguished by the boundary definitions used, and in such cases the names may be qualified with sensu stricto ("in the narrow sense") to denote usage in the exact meaning given by an author such as
4606-399: The Lesser Antilles . Both species of extant Kogia have also been observed stranded with plastics blocking their intestines. Pygmy sperm whale Physeter breviceps The pygmy sperm whale ( Kogia breviceps ) is one of two extant species in the family Kogiidae in the sperm whale superfamily . They are not often sighted at sea, and most of what is known about them comes from
4700-399: The fly agaric . Natural hybridisation presents a challenge to the concept of a reproductively isolated species, as fertile hybrids permit gene flow between two populations. For example, the carrion crow Corvus corone and the hooded crow Corvus cornix appear and are classified as separate species, yet they can hybridise where their geographical ranges overlap. A ring species is
4794-498: The jaguar ( Panthera onca ) of Latin America or the leopard ( Panthera pardus ) of Africa and Asia. In contrast, the scientific names of species are chosen to be unique and universal (except for some inter-code homonyms ); they are in two parts used together : the genus as in Puma , and the specific epithet as in concolor . A species is given a taxonomic name when a type specimen
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#17328954033034888-400: The museau de singe has been hypothesized of being a possible "pressure receptor". The positioning of this cushion structure in close proximity to the largest cavities closest to the museau de singe may suggest that it is a sound absorber used for echoreception. Although firm details concerning pygmy sperm whale reproduction are limited, they are believed to mate from April to September in
4982-454: The rostral part of the lower jaw. Unusually, adults lack enamel due to a mutation in the enamelysin gene , although enamel is present in very young individuals. Like other toothed whales , the pygmy sperm whale has a " melon ", a body of fat and wax in the head that it uses to focus and modulate the sounds it makes. The inner core of the melon has a higher wax content than the outer cortex. The inner core transmits sound more slowly than
5076-463: The small intestine , no caecum is present. The rostroventral dura of the brain contains a significant concentration of magnetite crystals, which suggests that K. breviceps can navigate by magnetoreception . Studies have also shown that compared to the sperm whale , the pygmy sperm whale brain has significantly fewer neurons, which may be connected to a decreased complexity in social interaction and group-based living. Like all toothed whales,
5170-449: The spermaceti organ . The oil was used to fuel kerosene lamps. Ambergris , a waste product produced by the whales, was also valuable to whalers as it was used by humans in cosmetics and perfume. They were not as heavily hunted as their larger counterpart Physeter macrocephalus , the sperm whale, which are typically 120,000 lb, thus preferred by whalers. The pygmy sperm whale is also rather inactive and slow rising when coming to
5264-526: The subfamily Kogiinae , and the sperm whale to the subfamily Physeterinae . Both have now been elevated to the family level. In 1878, naturalist James Hector synonymized the dwarf sperm whale with the pygmy sperm whale, with both being referred to as K. breviceps until 1998. The pygmy sperm whale is not much larger than many dolphins . They are about 1.2 m (3 ft 11 in) at birth, growing to about 3.5 m (11 ft) at maturity. Adults weigh about 400 kg (880 lb). The underside
5358-410: The vocal cords of humans. The stomach has three chambers. The first chamber, or forestomach, is not glandular, and opens directly into the second, fundic chamber, which is lined by digestive glands. A narrow tube runs from the second to the third, or pyloric, stomach, which is also glandular, and connects, via a sphincter , to the duodenum . Although fermentation of food material apparently occurs in
5452-406: The "cynical species concept", and arguing that far from being cynical, it usefully leads to an empirical taxonomy for any given group, based on taxonomists' experience. Other biologists have gone further and argued that we should abandon species entirely, and refer to the "Least Inclusive Taxonomic Units" (LITUs), a view that would be coherent with current evolutionary theory. The species concept
5546-622: The Origin of Species explained how species could arise by natural selection . That understanding was greatly extended in the 20th century through genetics and population ecology . Genetic variability arises from mutations and recombination , while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures . Genes can sometimes be exchanged between species by horizontal gene transfer ; new species can arise rapidly through hybridisation and polyploidy ; and species may become extinct for
5640-738: The Southern Hemisphere and March to August in the Northern Hemisphere. These whales become sexually mature at age 4-5, and like virtually all mammals, are iteroparous (reproducing many times during their lives). Once a female whale is impregnated, the average gestation period lasts 9–11 months, and unusually for cetaceans , the female gives birth to a single calf head-first. Newborn calves are about 1.2 metres (3 ft 11 in) in length, weighing 50 kg, and are weaned around one year of age. They are believed to live up to age 23. The whale makes very inconspicuous movements. It rises to
5734-405: The abbreviation "sp." in the singular or "spp." (standing for species pluralis , Latin for "multiple species") in the plural in place of the specific name or epithet (e.g. Canis sp.). This commonly occurs when authors are confident that some individuals belong to a particular genus but are not sure to which exact species they belong, as is common in paleontology . Authors may also use "spp." as
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#17328954033035828-570: The amount of hybridisation is insufficient to completely mix their respective gene pools . A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology , genes can move freely even between distantly related bacteria, possibly extending to the whole bacterial domain. As a rule of thumb, microbiologists have assumed that members of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA–DNA hybridisation to decide if they belong to
5922-477: The animals also make much lower-frequency "cries" at 1 to 2 kHz. Analysis of stomach contents suggests that pygmy sperm whales feed primarily on cephalopods , most commonly including bioluminescent species found in midwater environments. Most of the cephalopod hunting is known to be pelagic, and fairly shallow, within the first 100 m of the surface. The most common prey are reported to include glass squid , and lycoteuthid and ommastrephid squid, although
6016-474: The biological species concept, "the several versions" of the phylogenetic species concept, and the idea that species are of the same kind as higher taxa are not suitable for biodiversity studies (with the intention of estimating the number of species accurately). They further suggested that the concept works for both asexual and sexually-reproducing species. A version of the concept is Kevin de Queiroz 's "General Lineage Concept of Species". An ecological species
6110-505: The biological species concept, a cladistic species does not rely on reproductive isolation – its criteria are independent of processes that are integral in other concepts. Therefore, it applies to asexual lineages. However, it does not always provide clear cut and intuitively satisfying boundaries between taxa, and may require multiple sources of evidence, such as more than one polymorphic locus, to give plausible results. An evolutionary species, suggested by George Gaylord Simpson in 1951,
6204-428: The boundaries between closely related species become unclear with hybridisation , in a species complex of hundreds of similar microspecies , and in a ring species . Also, among organisms that reproduce only asexually , the concept of a reproductive species breaks down, and each clone is potentially a microspecies. Although none of these are entirely satisfactory definitions, and while the concept of species may not be
6298-648: The coast of many Southeast Asian countries. In 1985, the International Whaling Commission ended sperm whaling. The pygmy sperm whale is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas ( ASCOBANS ) and the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area ( ACCOBAMS ). The species
6392-433: The concept of a chronospecies can be applied. During anagenesis (evolution, not necessarily involving branching), some palaeontologists seek to identify a sequence of species, each one derived from the phyletically extinct one before through continuous, slow and more or less uniform change. In such a time sequence, some palaeontologists assess how much change is required for a morphologically distinct form to be considered
6486-435: The evidence to support hypotheses about evolutionarily divergent lineages that have maintained their hereditary integrity through time and space. Molecular markers may be used to determine diagnostic genetic differences in the nuclear or mitochondrial DNA of various species. For example, in a study done on fungi , studying the nucleotide characters using cladistic species produced the most accurate results in recognising
6580-610: The examination of stranded specimens. The pygmy sperm whale was first described by naturalist Henri Marie Ducrotay de Blainville in 1838. He based this on the head of an individual washed up on the coasts of Audierne in France in 1784, which was then stored in the Muséum d'histoire naturelle . He recognized it as a type of sperm whale and assigned it to the same genus as the sperm whale ( Physeter macrocephalus ) as Physeter breviceps . He noted its small size and nicknamed it " cachalot
6674-586: The head, responsible for sound production, in particular the presence of a spermaceti organ . Other phylogenetic research raises further questions over a potential relationship between kogiids and Ziphiidae . Other questions exist regarding the high relatedness in mitochondrial DNA between Platanista and kogiids. Fossil evidence is limited for this family, which potentially limits an understanding of their relationship to other extant cetaceans. Researchers have proposed that K. sima may represent at least two genetically unique species, and further genetic research
6768-499: The hindmost ribs do not connect with the vertebral column. Each of the flippers has seven carpals , and a variable number of phalanges in the digits, reportedly ranging from two in the first digit to as many as 10 in the second digit. No true innominate bone exists; it is replaced by a sheet of dense connective tissue . The hyoid bone is unusually large, and presumably has a role in the whale's suction feeding. The pygmy sperm has between 20 and 32 teeth, all of which are set into
6862-400: The known echoreception apparatus used by the pygmy sperm whale is linked to the fat-filled lower mandibles within the skull. However, compositional topography of the pygmy sperm whale's skull indicates abnormally large fatty jowls surrounding the mandibles, suggesting a more intricate echoreception apparatus. Additionally, an unusual cushion structure, of porous and spongy texture, found behind
6956-478: The numerous fungi species of all the concepts studied. Versions of the phylogenetic species concept that emphasise monophyly or diagnosability may lead to splitting of existing species, for example in Bovidae , by recognising old subspecies as species, despite the fact that there are no reproductive barriers, and populations may intergrade morphologically. Others have called this approach taxonomic inflation , diluting
7050-429: The outer layer, allowing it to refract sound into a highly directional beam. Behind the melon, separated by a thin membrane, is the spermaceti organ . Both the melon and the spermaceti organ are encased in a thick fibrous coat, resembling a bursa . The whale produces sound by moving air through the right nasal cavity, which includes a valvular structure, or museau de singe , with a thickened vocal reed, functioning like
7144-585: The paper is accepted for publication. The type material is usually held in a permanent repository, often the research collection of a major museum or university, that allows independent verification and the means to compare specimens. Describers of new species are asked to choose names that, in the words of the International Code of Zoological Nomenclature , are "appropriate, compact, euphonious, memorable, and do not cause offence". Books and articles sometimes intentionally do not identify species fully, using
7238-674: The person who named the species, while the antonym sensu lato ("in the broad sense") denotes a wider usage, for instance including other subspecies. Other abbreviations such as "auct." ("author"), and qualifiers such as "non" ("not") may be used to further clarify the sense in which the specified authors delineated or described the species. Species are subject to change, whether by evolving into new species, exchanging genes with other species, merging with other species or by becoming extinct. The evolutionary process by which biological populations of sexually-reproducing organisms evolve to become distinct or reproductively isolated as species
7332-427: The pygmy sperm whale hunts prey by echolocation . Sound produced for echolocation by many odontocetes come in the form of high-frequency clicks. The frequencies it uses are mostly ultrasonic, peaking around 125 kHz. The clicks from their echolocation has been recorded to last an average of 600 microseconds. When closing in on prey, the click repetition rate starts at 20 Hz and then begins to rise when nearing
7426-449: The ratio between observed brain size and expected brain size. The pygmy sperm whale has an EQ of 1.78, while the dwarf sperm whale's EQ is 1.63. Kogiidae do possess spermaceti in their head like sperm whales. However, kogiid spermaceti is unique as the whales are able to control its temperature. Kogiidae are also homodonts , showing teeth all of the same size and shape. Kogiidae possess a unique system of organs to produce sound, including
7520-487: The result of misclassification leading to questions on whether there really are any ring species. The commonly used names for kinds of organisms are often ambiguous: "cat" could mean the domestic cat, Felis catus , or the cat family, Felidae . Another problem with common names is that they often vary from place to place, so that puma, cougar, catamount, panther, painter and mountain lion all mean Puma concolor in various parts of America, while "panther" may also mean
7614-573: The ring. Ring species thus present a difficulty for any species concept that relies on reproductive isolation. However, ring species are at best rare. Proposed examples include the herring gull – lesser black-backed gull complex around the North pole, the Ensatina eschscholtzii group of 19 populations of salamanders in America, and the greenish warbler in Asia, but many so-called ring species have turned out to be
7708-508: The same species. This concept was narrowed in 2006 to a similarity of 98.7%. The average nucleotide identity (ANI) method quantifies genetic distance between entire genomes , using regions of about 10,000 base pairs . With enough data from genomes of one genus, algorithms can be used to categorize species, as for Pseudomonas avellanae in 2013, and for all sequenced bacteria and archaea since 2020. Observed ANI values among sequences appear to have an "ANI gap" at 85–95%, suggesting that
7802-529: The same species. When two species names are discovered to apply to the same species, the older species name is given priority and usually retained, and the newer name considered as a junior synonym, a process called synonymy . Dividing a taxon into multiple, often new, taxa is called splitting . Taxonomists are often referred to as "lumpers" or "splitters" by their colleagues, depending on their personal approach to recognising differences or commonalities between organisms. The circumscription of taxa, considered
7896-432: The sound waves move from a lower velocity material to a higher one during sound production, the sound undergoes inward refraction and becomes increasingly focused. Variation in fat density within the melon ultimately contributes to the production of highly directional, ultrasonic sound beams in front of the melon. The combined melon and spermaceti organ system cooperate to focus echolocative sounds. Like in most odontocetes,
7990-502: The species concept and making taxonomy unstable. Yet others defend this approach, considering "taxonomic inflation" pejorative and labelling the opposing view as "taxonomic conservatism"; claiming it is politically expedient to split species and recognise smaller populations at the species level, because this means they can more easily be included as endangered in the IUCN red list and can attract conservation legislation and funding. Unlike
8084-427: The species is not known. Pygmy sperm whales do not do well in captivity. The longest recorded survival in captivity is 21 months, and most captive individuals die within one month, mostly due to dehydration or dietary problems. Pygmy sperm whales have been reported as being forced to change their diets and foraging behaviors due to anthropic factors such as deep-sea trawling and increased fishing for cephalopods off
8178-399: The spermaceti organ contacts the posterior of the whale's melon. Fat from the core of the spermaceti organ helps direct sonic energy from the museau de singe to the melon. The melon acts as a sonic magnifier and gives directionality to sound pulses, making echolocation more efficient. Fat on the interior of the melon has a lower molecular weight lipid than the surrounding outer melon. Since
8272-407: The surface and as such do not bring much attention to themselves. However, they were easy targets, as they tended to swim slowly and lie motionless at the surface. Individuals have also been recorded killed in drift nets. Some stranded animals have been found with plastic bags in their stomachs, which may be a cause for concern. Whether these activities are causing long-term damage to the survival of
8366-716: The surface slowly, with little splash or blow, and remains there motionless for some time. In Japan , the whale was historically known as the "floating whale" because of this. Its dive is equally lacking in grand flourish - it simply drops out of view. The species has a tendency to back away from rather than approach boats. Breaching has been observed, but is not common. Pygmy sperm whales are normally either solitary or found in pairs, but have been seen in groups up to six. Dives have been estimated to last an average of 11 minutes, although longer dives up to 45 minutes have been reported. The ultrasonic clicks of pygmy sperm whales range from 60 to 200 kHz, peaking at 125 kHz, and
8460-407: The target. The pulse sounds that pygmy sperm whales make for echolocation are generated primarily from the museau de singe or monkey's muzzle, which is an anatomical structure located within the whale's skull that produces sound when air passes through its lips. The sound from the museau de singe is transferred to the attached cone of the spermaceti organ. Unique from other odontocetes,
8554-522: The two modern members of Kogia , which researchers suggested shows that this behavior has been part of Kogiidae for at least 3 million years. Extant kogiids travel in small groups and rarely surface, potentially to avoid predators like orcas . Kogiidae are deep diving whales, believed to dive up to depths of 500 m. Kogiids feed using a technique known as suction feeding, and their diet primarily consists of squid. Pygmy sperm whales are able to eat larger prey than dwarf sperm whales, although their diet as
8648-406: The whales also consume other squid, and octopuses . They have also been reported to eat some deep-sea shrimps , but, compared with dwarf sperm whales, relatively few fish. Predators may include great white sharks and killer whales . Pygmy sperm whales and dwarf sperm whales are unique among cetaceans in using a form of "ink" to evade predation in a manner similar to squid. Both species have
8742-591: The whaling and conservation laws in place for marine mammals, it is listed as "lower risk least concern" in the IUCN Red list. However, it faces some modern day issues; it is one of the most common stranded species in Florida sound. Due to its slow-moving and quiet nature, the species is at a higher risk of boat strikes. Its small size also allows for it to become a byproduct of commercial fishing, caught in seine nets . Anthropogenic noise caused by military activity and shipping
8836-537: The wild. It is difficult to define a species in a way that applies to all organisms. The debate about species concepts is called the species problem. The problem was recognised even in 1859, when Darwin wrote in On the Origin of Species : I was much struck how entirely vague and arbitrary is the distinction between species and varieties. He went on to write: No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of
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