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 ?
D dead;immobile, but spiracles begin to move slowly and irregularly after being placed in seawater.
Xenopus laevis tadpoles were observed to determine which forelimb emerges first in a species with a spiracle on both sides of the body.
n.: (1) larva, prothoracic spatula, sternal and ventral papillae, ventral view; (2) larval terminal segment, ventral view; (3) pupa, cephalic region, frontal view, and prothoracic spiracle; and (4) pupa, last abdominal segments, dorsal view; (5) male head, frontal view; (6) male flagellomere 5.
In this group, where large series of specimens are available for comparative study, there appears to be developmental and interspecific variation in the extent and intensity of the tergite's lateral sclerotization, so that, in some specimens, especially those that are teneral, the spiracle appears to open on an unsclerotized portion of the pleuron membrane.
13); propodeum with posterior transverse and anterior transverse carinae present, lateral longitudinal carina present anteriorly until spiracle level, lateromedian longitudinal carina present anteriorly until joining anterior transverse carina (Fig.
Abdominal spiracles I 0.18 mm long and 0.12 mm wide, shorter than spiracles II-VIII.
Areas that stained at pH 7.2 (fat body, developing legs and wings, first pupal spiracle, tracheae, punctate staining between dorsal thoracic muscles, and developing digestive system) stained more intensely at pH 6.0.
Collar segment with two very large papillae without setae in dorsal region; dorsal sclerotized plate occupying pro and mesothorax with a row of setae on superior margin; pleural papillae very well developed and one spiracle each side of the plate (Figure 12).
The shape of the pronotal shoulder, lower margin of the pronotum, basalar sclerite, and propodeal spiracle are important.
Those characters include the shape of the propodeal spiracle, length of the mesotibial spur, presence or absence of hairs on the body, and the length, density, and type of pubescence.
At this stage, the rays displayed tonic immobility, absence of tail and fin movements, absence of reaction to external touch and frequency of spiracle beats of less than 10 per minute.
T1 with spiracular area barely or not projecting, not forming a concavity behind spiracle (Fig.