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Summary: 461
The view of tetrapod evolution typically presented in
undergraduate textbooks is that limbs evolved specifically for
terrestrial locomotion, which was of selective advantage in a
Devonian environment subject to drought (e.g. Campbell et al.,
1999; Pough et al., 2002). Sarcopterygian fishes are pictured
as moving from stream to stream, or pond to pond, using their
lobed fins as flexible props; these fins eventually gave rise to
full-fledged tetrapod limbs (Campbell et al., 1999). The lobed
fins were thought to be, in essence, preadapted for later
function as terrestrial limbs; the movement pattern of the
paired fins in the coelacanth strongly resembles a tetrapod trot,
although Latimeria uses its fins for aquatic propulsion (Fricke
et al., 1987).
However, in the past 15ˇyears, evidence has emerged that
challenges this view. Edwards (1989) points out that bottom-
dwelling antennariid anglerfishes use their paired pectoral and
pelvic fins to traverse the substrate in a manner analogous to
limbs. The fins of these animals are fleshy and outwardly
resemble limbs. Antennariids even switch between two
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