Chaetotaxy is the arrangement of

bristles A bristle is a stiff hair or feather (natural or artificial), either on an animal, such as a pig, a plant, or on a tool such as a brush or broom. Synthetic types Synthetic materials such as nylon are also used to make bristles in items such as b ...

(macrochaetae) on an

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

annelid The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to vario ...

, or

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

based on their position and size. For example, it is important in

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advance ...

, in which group it was formalised by Ernst August Girschner. The term chaetotaxy was later proposed by

Carl Robert Osten-Sacken Carl Robert Osten-Sacken or Carl-Robert Romanovich, Baron von der Osten-Sacken, Baron Osten Sacken (21 August 1828, – 20 May 1906) was a German-Russian diplomat and entomologist. He served as the Russian consul general in New York City duri ...

. The chaetotaxy of a fly might include :- acrostichal, dorsocentral, humeral, mesopleural, sternopleural, notopleural, postalar, supra-alar and scutellar bristles on the thorax; dorsal, posterodorsal, anterodorsal, ventral, posteroventral and anteroventral bristles on the legs and ocellar, orbital, postvertical, vibrissal, outer vertical and inner vertical bristles on the head. Chaetotaxy is also used in determining homology in certain morphological traits, as well as providing information about the

phylogeny A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or Taxon, taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, M ...

between taxa. For example, chaetotaxy has been used to clarify evolutionary relationships in

Collembola Springtails (class Collembola) form the largest of the three lineages of modern hexapods that are no longer considered insects. Although the three lineages are sometimes grouped together in a class called Entognatha because they have internal m ...

, as well as identify new

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), ...

References

*Capinera, J.L. (editor). 2008. ''Encyclopedia of Entomology'', 2nd Edition. Vols. 1-4. Springer, Dordrecht, The Netherlands. {{ISBN, 1-4020-6242-7. *McAlpine, J.F. 1981 Morphology and terminology - Adults. - In: McAlpine, J.P. et al. (eds.): ''Manual of Nearctic Diptera'', vol. 1; p. 9-63 - Ottawa: Research Branch, Agriculture Canada, Monograph 27. *Steyskal, G.C. (1976) The terminology of bristles on the upper back of the head in the higher Diptera. ''Journal of the Kansas Entomological Society'' 49 (2): 155-159.

External links

CSIRO Anatomy atlasTOL
Description of the family Clusiidae including chaetotaxy.

References

External links

See also