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Nautilus Stenomphalus
''Nautilus stenomphalus'', also known as the white-patch nautilus, is a species of nautilus native to the Great Barrier Reef. ''N. stenomphalus'' is very similar to '' N. pompilius'' and may in fact represent a subspecies. It is separated by the absence of a thickened callus and the presence of white patches in the umbilical and shoulder regions of the shell. The sheaths of this species have scalloped edges compared with the smooth sheaths of ''N. pompilius''. ''N. stenomphalus'' also differs slightly in hood ornamentation. The shell is usually up to around 180 mm in diameter, although the largest specimen ever recorded measured 201 mm. Distribution ''Nautilus stenomphalus'' are pelagic molluscs belonging to the Nautilidae cephalopod family predominantly found across coral reefs along the Indo-Pacific region.Ward, Peter, Frederick Dooley, and Gregory Jeff Barord. "Nautilus: biology, systematics, and paleobiology as viewed from 2015." Swiss Journal of Palaeontology 13 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Brettingham Sowerby II
George Brettingham Sowerby II (1812 – 26 July 1884) was a British naturalist, illustrator, and conchologist. Together with his father, George Brettingham Sowerby I, he published the ''Thesaurus Conchyliorum'' and other illustrated works on molluscs. He was an elected a Fellow of the Linnean Society on 7 May 1844. He was the father of George Brettingham Sowerby III, also a malacologist. He died on 26 July 1884 and is buried on the west side of Highgate Cemetery with his father George Brettingham Sowerby I George Brettingham Sowerby I (12 August 1788 – 26 July 1854) was a British natural history, naturalist, illustrator and Conchology, conchologist. Life He was the second son of James Sowerby. George was educated at home under private tutors, ... and sister Charlotte Caroline Sowerby. See also * Sowerby family References * H. Crosse & P. Fischer, 1885. ''Nécrologie''. Journal de Conchyliologie 33(1): 80. * K. v. W. Palmer, 1965. ''Who were the Sowerbys?'' A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tentacle
In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work mainly like muscular hydrostats. Most forms of tentacles are used for grasping and feeding. Many are sensory organs, variously receptive to touch, vision, or to the smell or taste of particular foods or threats. Examples of such tentacles are the eyestalks of various kinds of snails. Some kinds of tentacles have both sensory and manipulatory functions. A tentacle is similar to a cirrus, but a cirrus is an organ that usually lacks the tentacle's strength, size, flexibility, or sensitivity. A nautilus has cirri, but a squid has tentacles. Invertebrates Molluscs Many molluscs have tentacles of one form or another. The most familiar are those of the pulmonate land snails, which usually have two sets of tentacles on the head: when ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mark Norman (marine Biologist)
Mark Douglas Norman (1960s to present) is a scientist living in southern Australia. He works as a Chief Conservation Scientist with Parks Victoria. Prior to 2016 he worked as a curator and marine biologist through the University of Melbourne and Museum Victoria. For over a decade in this role, Norman worked exclusively with cephalopods and was a leading scientist in the field, having discovered over 150 new species of octopuses. The best known of these is probably the mimic octopus. Notable publications * Norman M., Reid A. (2000) A Guide to Squid, Cuttlefish and Octopuses of Australasia (''The Gould League of Australia and CSIRO Publishing'': Melbourne). * Norman M. (2000) ''Cephalopods: A World Guide'' (''ConchBooks'': Hackenheim, Germany)''.'' This book contains over 800 color photographs of cephalopods in their natural habitat. Species described by Mark Norman The following species have been described by M. Norman either individually or with co-authors. * '' Amelocto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus 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, which is around 20% of the shell diameter at its widest point. This species, along with the closely related '' A. perforatus'', were originally placed in the 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 from members of the genus ''Nautilus''. The shell is usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus Macromphalus
''Nautilus macromphalus'', the bellybutton nautilus, is a species of nautilus native to the waters off New Caledonia and northeastern Australia. The shell of this species lacks a callus, leaving the umbilicus exposed, in which the inner coils of the shell are visible. This opening constitutes about 15% of the shell diameter at its widest point. Like all ''Nautilus'' species, ''N. macromphalus'' usually lives at depths of several hundred metres. During the night, however, they rise to much shallower waters (2 to 20 m depth) to feed. The tentacles of this species are long and thin, having raised ridges which help provide grip when catching prey. ''N. macromphalus'' is the smallest species of nautilus. The shell is usually up to around 16 cm in diameter, although the largest specimen ever recorded measured 180 mm. More than 35 shells of ''N. macromphalus'' dating to around 6400–7100 years BP were found in a cenote on Lifou, the Loyalty Islands. Based on these rad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus Belauensis
The Palau nautilus (''Nautilus belauensis'') is a nautiloid mainly found off of Palau in the Western Carolines. It can be found on fore reef slopes, at depths of 95m-504m (311'-1,653'), though typically preferring a range of 150m-300m (492'-984'), where water temperatures stay around 16.6 °C (61.88°F) and do not go much lower than 9.4 °C (48.92°F). ''N. belauensis'' are highly mobile, epibenthic scavengers and opportunistic predators which rely mostly on scent for finding food. They are active both diurnally and nocturnally within their preferred depth ranges, although most shallow-water incursions are, generally, nocturnal events that coincide with greatly diminished fish activities. Anatomy ''N. belauensis'' shell is similar to that of '' N. pompilius'', but it is distinguished by its larger mean mature shell diameter and shell weight. Its shell characteristic pattern consists of bifurcating brown to red stripes that extend from the umbilicus to the venter without ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotypic Plasticity
Phenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompasses all types of environmentally induced changes (e.g. morphological, physiological, behavioural, phenological) that may or may not be permanent throughout an individual's lifespan. The term was originally used to describe developmental effects on morphological characters, but is now more broadly used to describe all phenotypic responses to environmental change, such as acclimation (acclimatization), as well as learning. The special case when differences in environment induce discrete phenotypes is termed polyphenism. Generally, phenotypic plasticity is more important for immobile organisms (e.g. plants) than mobile organisms (e.g. most animals), as mobile organisms can often move away from unfavourable environments. Nevertheless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatric Speciation
Sympatric speciation is the evolution of a new species from a surviving Common descent, ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography, ''sympatric'' and ''sympatry'' are terms referring to organisms whose Range (biology), ranges overlap so that they occur together at least in some places. If these organisms are closely related (e.g. sister species), such a distribution may be the result of sympatric speciation. Etymologically, sympatry is derived . The term was coined by Edward Bagnall Poulton in 1904, who explains the derivation. Sympatric speciation is one of three traditional geographic modes of speciation.Futuyma, D. J. 2001. ''Evolution'' (2nd edition). Sinauer Associates, Inc. Allopatric speciation is the evolution of species caused by the geographic isolation of two or more populations of a species. In this case, divergence is facilitated by the absence of gene flow. Parapatric speciation is the evolut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population, or a species (extinct or Extant taxon, extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed ''monophyletic'' (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming Taxon, taxa that are not clades; that is, taxa that are not Monophyly, monophyletic. Some of the relationships between organisms that the molecul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetics
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data and observed heritable traits of DNA sequences, protein amino acid sequences, and morphology. The results are a phylogenetic tree—a diagram depicting the hypothetical relationships among the organisms, reflecting their inferred evolutionary history. The tips of a phylogenetic tree represent the observed entities, which can be living taxa or fossils. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the taxa represented on the tree. An unrooted tree diagram (a network) makes no assumption about directionality of character state transformation, and does not show the origin or "root" of the taxa in question. In addition to their use for inferring phylogenetic pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid Speciation
Hybrid speciation is a form of speciation where hybridization between two different species leads to a new species, reproductively isolated from the parent species. Previously, reproductive isolation between two species and their parents was thought to be particularly difficult to achieve, and thus hybrid species were thought to be very rare. With DNA analysis becoming more accessible in the 1990s, hybrid speciation has been shown to be a somewhat common phenomenon, particularly in plants. In botanical nomenclature, a hybrid species is also called a nothospecies. Hybrid species are by their nature polyphyletic. Ecology A hybrid may occasionally be better fitted to the local environment than the parental lineage, and as such, natural selection may favor these individuals. If reproductive isolation is subsequently achieved, a separate species may arise. Reproductive isolation may be genetic, ecological, behavioral, spatial, or a combination of these. If reproductive isolation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apomorphy And Synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
