sinistral
/ˈsɪnɪstr(ə)l
/adjective
1Of or on the left side or the left hand (the opposite of dextral).Nevertheless, sinistral and dextral Pb elements are virtually mirror images, that is, they are more alike than the corresponding elements in L. variabilis.
1.1Left-handed.Although sinistral individuals are known in many normally dextral species, left-handedness as a characteristic of species is rare in most gastropod clades.
1.2 Geology Relating to or denoting a strike-slip fault in which the motion of the block on the further side of the fault from an observer is towards the left.This paper tentatively identifies two lineaments and a fault that may relate to sinistral strike-slip faulting in the pre-Paradox Formation basement beneath Upheaval Dome....
- Although data on vertical displacement on the Klima fault zone are limited, the horizontal component is clearly much larger, and the Klima fault zone represents a sinistral strike-slip fault.
- In conclusion, the geological characteristics of the South China Sea cannot be explained by a pull-apart model involving a releasing bend of a sinistral strike-slip fault.
1.3 Zoology (Of a spiral mollusc shell) with whorls rising to the left and coiling in a clockwise direction.If the umbilicate side is directed downward and the flat side upward, this gives the impression the shell is sinistral or a left-handed spiral, because the aperture when held toward the observer is on the left....
- These gastropods have slender, high-spired, multiwhorled shells bearing a sinistral protoconch and were united by Knight in the family Streptacididae.
- The latter species has a smooth, valvatiform, dextrally coiled teleoconch and a sinistral, anastrophic (coaxial heterostrophic) protoconch.
noun
A left-handed person.Left-handed children, or sinistrals, often have a difficult time in a world geared overwhelmingly to the right-handed.
Derivatives
sinistrality
- There is no trend from dextrality to sinistrality, but rather large clades characterized by one form or the other, sometimes with large-ish subclades of the complementary type.
- Further evidence that species-level sinistrality originated in environments where predator-induced selection is weak comes from the biology of living left-handed species.
- Such selection is inimical to the evolution of traits like sinistrality that, at least in their early stages of development, are accompanied by mildly deleterious side effects.
sinistrally
- Both species described here are sinistrally coiled, but a similar pattern of ornamentation is present on two Pennsylvanian species that are dextrally coiled.
- The outer shell surface of both sinistrally coiled species of Crassimarginata is ornamented by distinct costae, but the dextrally coiled shells of Yukonoconcha seem to be smooth.
- The sinistrally transtensional Louisburgh Basin contains PrIdolI fluviatile sediments and, probably, dates the end of transpressional deformation.