Question please about δεικνὺς as it's used in the following passage from Lucian's "A True Story" (book 2, sect 27)
ὁ δὲ ἔφασκεν ἀφίξεσθαι μὲν εἰς τὴν πατρίδα πολλὰ πρότερον πλανηθέντα καὶ κινδυνεύσαντα, τὸν δὲ χρόνον οὐκέτι τῆς ἐπανόδου προσθεῖναι ἠθέλησεν: ἀλλὰ δὴ καὶ δεικνὺς τὰς πλησίον νήσους—ἐφαίνοντο δὲ πέντε τὸν ἀριθμόν, ἄλλη δὲ ἕκτη πόρρωθεν — ...
The commentary lists δεικνὺς as a perfect participle of deiknumi, while Perseus says it's aorist. But I can't seem to get from verb to participle using either stem, even with vowel contraction. Am I doing it wrong or is formation of the participle just irregular, and which tense is it? Thanks very much for any help,