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Allonautilus
The genus ''Allonautilus'' contains two species of nautiluses, which have a significantly different Morphology (biology), morphology from those placed in the sister taxon ''Nautilus (genus), Nautilus''. Mitogenome comparisons between ''Allonautilus'' and ''Nautilus'' confirm this split as the oldest divergence among living nautiloids, justifying their placement in separate genera. Live individuals of ''Allonautilus scrobiculatus'' have only been collected in Papua New Guinea and the Solomon Islands. Little is known about their biology because they live in deep waters, whereas the better-understood genus ''Nautilus (genus), Nautilus'' lives closer to the surface. ''Allonautilus perforatus'' is only known from shells washed ashore with no observations of live specimens to date. Despite the rarity of live sightings of individuals of this genus, genetic diversity among the limited collected live samples indicate relatively large populations persisting for at least ''Allonautilus scrob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allonautilus Scrobiculatus
''Allonautilus scrobiculatus'', also known as the crusty nautilus or fuzzy nautilus, is a species of nautilus native to the waters around New Guinea, specifically New Britain and Milne Bay, and the Solomon Islands. ''A. scrobiculatus'' is recognizable by the large open Umbilicus (mollusc), umbilicus, which is around 20% of the shell diameter at its widest point. This species, along with the closely related ''Allonautilus perforatus, A. perforatus'', were originally placed in the genus ''Nautilus (genus), Nautilus'', but have recently been given their own genus on account of significant morphological differences.Ward, P.D. & W.B. Saunders 1997''Allonautilus'': a new genus of living nautiloid cephalopod and its bearing on phylogeny of the Nautilida ''Journal of Paleontology'' 71(6): 1054–1064. The most obvious are features of the shell, including crease and an encrusting layer (periostracum) that covers most of the shell. Gills and reproductive structures also differ significantly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allonautilus Perforatus
''Allonautilus perforatus'', also known as the Bali chambered nautilus or the Indonesian nautilus, is a species of nautilus native to the waters around Bali, Indonesia. It is known only from drifted shells and, as such, is the least studied of the seven recognized nautilus species. Thus, not much is known about it outside of the shell. Habitat and distribution The nautilus is reported to live on the coastal reefs of Baliand Papua New Guinea. They have been reported to live in nearby deep-water habitats as well. ''A. perforatus'' has been estimated to live at depths of 100~600 meters much like other extant Nautiloids. Ultimately little is known about the exact distribution of ''A. perforatus'' compared with the more abundant relatives such as '' A. scrobiculatus.'' Shells of the nautilus are sold in Balinese market placesWard, P.D. & W.B. Saunders 1997''Allonautilus'': a new genus of living nautiloid cephalopod and its bearing on phylogeny of the Nautilida ''Journal of Paleontol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus
A nautilus (; ) is any of the various species within the cephalopod family Nautilidae. This is the sole extant family of the superfamily Nautilaceae and the suborder Nautilina. It comprises nine living species in two genera, the type genus, type of which is the genus ''Nautilus (genus), Nautilus''. Though it more specifically refers to the species ''chambered nautilus, Nautilus pompilius'', the name chambered nautilus is also used for any of the Nautilidae. All are protected under CITES CITES Appendix II, Appendix II. Depending on species, adult shell diameter is between . The Nautilidae, both extant and extinct, are characterized by involute or more or less convoluted shells that are generally smooth, with compressed or depressed whorl (mollusc), whorl sections, straight to sinuous Suture (anatomy), sutures, and a tubular, generally central siphuncle.Kümmel, B. 1964. Nautiloidae-Nautilida, in the Treatise on Invertebrate Paleontology, Geological Society of America and Univ of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus (genus)
''Nautilus'' is a marine cephalopod genus in the Mollusca, mollusk family (biology), family Nautilidae. Species in this genus differ significantly, Morphology (biology), morphologically, from the two nautilus species in the adjacent sister-taxon ''Allonautilus''. The oldest fossils of the genus are known from the Late Eocene Hoko River Formation, in Washington State and from Late-Eocene to Early Oligocene sediments in Kazakhstan. The oldest fossils of the modern species ''Nautilus pompilius'' are from Early Pleistocene sediments off the coast of Luzon in the Philippines. The commonly used term 'nautilus' usually refers to any of the surviving members of ''Nautilidae'', and more specifically to the ''Nautilus pompilius'' species. The entire family of ''Nautilidae'', including all species in the genera ''Nautilus'' and ''Allonautilus'', is listed on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Various authors claim th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periostracum
The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods and bivalves, but it is also found in cephalopods such as ''Allonautilus scrobiculatus''. The periostracum is an integral part of the shell, and it forms as the shell forms, along with the other shell layers. The periostracum is used to protect the organism from corrosion. The periostracum is visible as the outer layer of the shell of many molluscan species from terrestrial, freshwater, and marine habitats, and may be seen in land snails, river mussels, and other kinds of freshwater bivalves, as well as in many kinds of marine shelled molluscs. The word ''periostracum'' means "around the shell", meaning that the periostracum is wrapped around what is usually the more calcareous part of the shell. Technically, the calcareous part of the sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Ward (paleontologist)
Peter Douglas Ward (born May 12, 1949) is an American paleontologist and professor at the University of Washington, Seattle, and Sprigg Institute of Geobiology at the University of Adelaide. He has written numerous popular science works for a general audience and is also an adviser to the Microbes Mind Forum. In 2000, along with his co-author Donald E. Brownlee, he co-originated the term '' Rare Earth'' and developed the Medea hypothesis alleging that multicellular life is ultimately self-destructive. Life and work His parents, Joseph and Ruth Ward, moved to Seattle following World War II. Ward grew up in the Seward Park neighborhood of Seattle, attending Franklin High School, and he spent time during summers at a family summer cabin on Orcas Island. Ward's academic career has included teaching posts and professional connections with Ohio State University, the NASA Astrobiology Institute, the University of California, McMaster University (where he received his Ph.D. in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. Phylogeneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
A species () is often defined as the largest group 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 Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour, or ecological niche. In addition, palaeontologists 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 a binomial nomenclature, two-part name, a "binomen". The first part of a binomen is the name of a genus to which the species belongs. The second part is called the specific name (zoology), specific name or the specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology (from Ancient Greek μορφή (morphḗ) "form", and λόγος (lógos) "word, study, research") is the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, color, pattern, size), as well as the form and structure of internal parts like bones and organs, i.e., anatomy. This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of the overall structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Fried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxon
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion, especially in the context of rank-based (" Linnaean") nomenclature (much less so under phylogenetic nomenclature). If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were presumably set forth in prehistoric times by hunter-gatherers, as suggested by the fairly sophisticated folk taxonomies. Much later, Aristotle, and later st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Papua New Guinea
Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean north of Australia. It has Indonesia–Papua New Guinea border, a land border with Indonesia to the west and neighbours Australia to the south and the Solomon Islands to the east. Its capital, on its southern coast, is Port Moresby. The country is the world's third largest list of island countries, island country, with an area of . The nation was split in the 1880s between German New Guinea in the North and the Territory of Papua, British Territory of Papua in the South, the latter of which was ceded to Australia in 1902. All of present-day Papua New Guinea came under Australian control following World War I, with the legally distinct Territory of New Guinea being established out of the former German colony as a League of Nations mandate. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solomon Islands
Solomon Islands, also known simply as the Solomons,John Prados, ''Islands of Destiny'', Dutton Caliber, 2012, p,20 and passim is an island country consisting of six major islands and over 1000 smaller islands in Melanesia, part of Oceania, to the northeast of Australia. It is directly adjacent to Autonomous Region of Bougainville, Bougainville, a part of Papua New Guinea to the west, Australia to the southwest, New Caledonia and Vanuatu to the southeast, Fiji, Wallis and Futuna, and Tuvalu to the east, and Nauru and the Federated States of Micronesia to the north. It has a total area of 28,896 square kilometres (11,157 sq mi), and a population of 734,887 according to the official estimates for mid-2023. Its capital and largest city, Honiara, is located on the largest island, Guadalcanal. The country takes its name from the wider area of the Solomon Islands (archipelago), Solomon Islands archipelago, which is a collection of Melanesian islands that also includes the Autonomous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
