Annulus (zoology)

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In zoology, an annulus is an external circular ring. [1] Annuli are commonly found in segmented animals such as earthworms and leeches. The bodies of these annelids are externally marked by annuli that are arranged in series with each other.

An annulus may also be an indication of growth in certain species, similar to dendrochronology. For example, in fish, it is a series of concentric rings (or annuli) formed in the scales of bony fish. [2] In bivalve mollusks, annuli are concentric growth rings in their shells.

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Actinopterygii Class of ray-finned bony fishes

Actinopterygii, members of which are known as ray-finned fishes, is a clade of the bony fishes.

Chondrichthyes Class of jawed cartilagenous fishes

Chondrichthyes is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or bony fishes, which have skeletons primarily composed of bone tissue. Chondrichthyes are jawed vertebrates with paired fins, paired nares, scales, and a heart with its chambers in series. Extant chondrichthyes range in size from the 10 cm finless sleeper ray to the 10 m whale shark.

Osteichthyes Diverse group of fish with skeletons of bone rather than a cartilage

Osteichthyes, popularly referred to as the bony fish, is a diverse taxonomic group of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage. The vast majority of fish are members of Osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, and over 435 families and 28,000 species. It is the largest class of vertebrates in existence today. The group Osteichthyes is divided into the ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii). The oldest known fossils of bony fish are about 420 million years old, which are also transitional fossils, showing a tooth pattern that is in between the tooth rows of sharks and bony fishes.

Scale (anatomy) Small rigid plate that grows out of an animals skin

In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration. Scales are quite common and have evolved multiple times through convergent evolution, with varying structure and function.

Gnathostomata Infraphylum of jawed vertebrates

Gnathostomata are the jawed vertebrates. The term derives from Greek: γνάθος "jaw" + στόμα "mouth". Gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates. In addition to opposing jaws, living gnathostomes have teeth, paired appendages, and a horizontal semicircular canal of the inner ear, along with physiological and cellular anatomical characters such as the myelin sheaths of neurons. Another is an adaptive immune system that uses V(D)J recombination to create antigen recognition sites, rather than using genetic recombination in the variable lymphocyte receptor gene.

Fish anatomy study of the form or morphology of fishes

Fish anatomy is the study of the form or morphology of fishes. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish. In practice, fish anatomy and fish physiology complement each other, the former dealing with the structure of a fish, its organs or component parts and how they are put together, such as might be observed on the dissecting table or under the microscope, and the latter dealing with how those components function together in living fish.

Annulus (mathematics) region between two concentric circles

In mathematics, an annulus is the region between two concentric circles. Informally, it is shaped like a ring or a hardware washer. The word "annulus" is borrowed from the Latin word anulus or annulus meaning 'little ring'. The adjectival form is annular.

Otolith

An otolith, also called statoconium or otoconium or statolith, is a calcium carbonate structure in the saccule or utricle of the inner ear, specifically in the vestibular system of vertebrates. The saccule and utricle, in turn, together make the otolith organs. These organs are what allows an organism, including humans, to perceive linear acceleration, both horizontally and vertically (gravity). They have been identified in both extinct and extant vertebrates.

A dermal bone or investing bone or membrane bone is a bony structure derived from intramembranous ossification forming components of the vertebrate skeleton including much of the skull, jaws, gill covers, shoulder girdle and fin spines rays (lepidotrichia), and the shell. In contrast to endochondral bone, dermal bone does not form from cartilage that then calcifies, and it is often ornamented. Dermal bone is formed within the dermis and grows by accretion only – the outer portion of the bone is deposited by osteoblasts.

Lingcod Species of fishes

The lingcod or ling cod, also known as the buffalo cod or cultus cod, is a fish of the greenling family Hexagrammidae. It is the only extant member of the genus Ophiodon. A slightly larger, extinct species, Ophiodon ozymandias, is known from fossils from the Late Miocene of Southern California.

This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes.

Goldstripe sardinella Species of fish

The goldstripe sardinella is a species of fish of the family Clupeidae. It is native to shallow tropical waters of the western Indo-Pacific, living at depths down to 70 m, and being associated with coral reefs. It grows up to 17 cm in length and forms large schools.

Hanako was a scarlet koi fish owned by several individuals, the last of whom was Dr. Komei Koshihara. The name Hanako translates to "flower girl" in Japanese. Far exceeding the average lifespan for her breed, she was reportedly 226 years old at the time of her death. Her age was determined in 1966 by removing two of her scales and examining them extensively. At this time, Hanako weighed 7.5 kg and measured 70 cm in length. Once the scales were fully analyzed, it was determined that she was 215 years old. In July 1974, a study of the growth rings of one of the koi's scales reported that Hanako was 226 years old. She is, to date, the longest-lived koi fish ever recorded. There has been dispute as to the veracity of these longevity claims.

Fish bone

Fish bone is any bone of a fish. Fish bone also includes the bony, delicate parts of the skeleton of bony fish, such as ribs and fin rays, but especially the ossification of connective tissue lying transversely inclined backwards to the ribs between the muscle segments and having no contact with the spine.

Age determination in dinosaurs is mainly used to determine the approximate age of a dinosaur when the animal died.

Astronomical rings Early astronomical instrument

Astronomical rings, also known as Gemma's rings, are an early astronomical instrument. The instrument consists of three rings, representing the celestial equator, declination, and the meridian.

<i>Labeo bata</i> Species of fish

Labeo bata is a fish in genus Labeo. It is commonly known as bata, and is a native fish to India and Bangladesh.

Fish scale Rigid covering growing atop a fishs skin

A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages. The term scale derives from the Old French "escale", meaning a shell pod or husk.

Age determination in fish

Knowledge of fish age characteristics is necessary for stock assessments, and to develop management or conservation plans. Size is generally associated with age; however, there are variations in size at any particular age for most fish species making it difficult to estimate one from the other with precision. Therefore, researchers interested in determining a fish age look for structures which increase incrementally with age. The most commonly used techniques involve counting natural growth rings on the scales, otoliths, vertebrae, fin spines, eye lenses, teeth, or bones of the jaw, pectoral girdle, and opercular series. Even reliable aging techniques may vary among species; often, several different bony structures are compared among a population in order to determine the most accurate method.

Sufetula bilinealis is a moth in the family Crambidae. It was described by George Hampson in 1912. It is found in Papua New Guinea.

References

  1. Hickman, Cleveland; Roberts, Larry; Keen, Susan; Larson, Allan; l'Anson, Helen; Eisenhour, David (2008). Integrated Principles of Zoology (14th ed.). New York: McGraw-Hill Higher Education. pp. 362–383. ISBN   978-0-07-297004-3.
  2. Allaby, Michael (1999). "Dictionary definition of annulus". encyclopedia.com. Retrieved 11 July 2010. annulus: One of a series of concentric rings or bands of varying width and opacity which are formed in the scales of bony fish. Winter rings are often narrower and denser than summer rings. The number of annuli is indicative of the age of a fish.