Reptile in bottom of pit turned on Lucifer (6,5)

I believe the answer is:

thorny devil

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'reptile' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'bottom of pit turned on lucifer' is the wordplay.
'bottom of' says to take the final letters.
'turned on' becomes 'horny' (synonyms).
'lucifer' becomes 'Devil' (synonyms).
The final letter of 'pit' is 't'.
't'+'horny'+'devil'='THORNY DEVIL'

'in' is the link.

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I've seen this clue in The Independent.

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