spiracle

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spi·ra·cle

(spī'ră-kĕl, spir-),
An aperture for breathing in arthropods and cetaceans; a similar opening in sharks and related fishes.
[L. spiraculum, fr. spiro, to breathe]

spiracle

(spĭr′ə-kəl, spī′rə-)
n.
1. Zoology A respiratory aperture, especially:
a. Any of several tracheal openings in the exoskeleton of an insect, spider, or other terrestrial arthropod.
b. A small respiratory opening behind the eye of most sharks and rays and certain other fishes.
c. The blowhole of a cetacean.
2. An aperture or opening through which air is admitted and expelled.

spi·rac′u·lar (spī-răk′yə-lər, spĭ-) adj.

spiracle

  1. (in fish) a gill-like cleft that opens behind the eye and through which water is drawn in for gaseous exchange (as it is through the mouth) by the expansion of the pharyngeal cavity. It is absent in many bony fish.
  2. (in arthropods) the exterior opening of the tracheae, often possessing valves that can close to prevent water loss.
References in periodicals archive ?
In Nothochrysinae, a spiracular opening on the eighth female tergite typifies the Pamochrysa grouping; however the numbers of exemplars/genus are very small (n = 1/genus).
Its is distinct, however with its closest relative (dromedarii) in having without lateral projections of basis capituli, dorsal posterior margin angular and deeply concave, conscutum with deep and long cervical grooves but very short marginal grooves, postero-median groove does not reach the parma, and remain separated, paramedian festoons parma generally rectangular and broad, large punctuations on caudal and lateral fields but sparse, however small punctuations always dense, transverse ridges present in caudal area, broad, angle of paraparmal festoons eject, sub-anal plates smaller in size and a very short dorsal prolongation of the spiracular plates and not clear from the body of the plate.
The proximate mechanism by which high ultrasonic sensitivity is achieved is through a sophisticated anatomical arrangement of the hearing organ in the tibia of the foreleg, in conjunction with a tracheal tube which connects the inner surface of the ear drum with the lateral surface of the body wall through a spiracular opening.
The spiracular organ of sharks and skates: anatomical evidence indicating a mechanoreceptive role.
Spiracles of abdominal segments I-VIII similar in size; distance between the two lobes of respiratory plate of spiracles less than dorsoventral diameter of bulla; dorsal surface of segment I-VIII with a single row of short setae per annulet, some long setae interspersed between short setae; dorsum of segment VII with 2 annulets; segments IX and X fused, covered with irregular rows of short setae; spiracular area of abdominal segments I-VIII with 10-15 setae, frequently 11.
Attempts were made to identify these two variants on the basis of spiracular indices in rural areas of Rajasthan.
Petiole (Tergite-1) elongate, distance between primary and secondary spiracular tubercles longer than width at spiracles (Fig.
1B, 1D, 2B); connexival segments partly fused, intersegmental lines only vaguely indicated; dorsal and ventral surfaces of connexivum flat, lateral edge keeled, ventral surface delimited by a distinct, deep furrow; spiracular callosities with distinct, yellow prespiracular portion, indistinct postspiracular portion not differing from the respective sternite in color; trichobothria of each segment situated immediately at the lateral margin of the respective mediosternite, arranged in a line with the spiracle; abdominal sternites (=mediosternites) curved, sternite Vil normal, not projecting deeply into sternite VI along midline ([male], [female]) (Fig.
The Metopiinae is a medium-sized cosmopolitan subfamily of Ichneumonidae with members distinguished by having the lower face and clypeus confluent and not separated by an impressed groove; most species possess a shelf-like protuberance below the antennal insertion and having the pronotum laterally concave and rather broadly rounded posteriorly, broadly occluding the spiracular sclerite.
In both species, the spiracular tracheal trunks of the metathorax produce and store an odorous, noxious secretion that is sprayed out at attacking predators.
Spiracles on abdominal segments 2-7; a pair of trichobothria on abdominal segments 3-6, mesad of spiracular line (Fig.