More on Sea-monsters

Earlier, I inquired about the frequency of the use of cete, which I had come across in Proba's Cento. Bret Mulligan commented that one often finds it in Late Antique exegesis, especially of the Book of Jonah. Today I was reading the anonymous Late Antique poem De Iona Propheta and came across the word again, this time in the singular and spelled with an ending in the Latinized -us instead of Greek -os (interestingly, Lewis' Elementary Latin Dictionary enters the word as cetos, while Lewis & Short uses cetus and puts in parentheses afterwards 'acc. to the Gr. cētŏs).

The anonymous author of De Iona Propheta then uses another word transliterated from Greek in the following line. Here are the two lines in question (85-6):

Iamque illic imo exoriens de gurgite cetus,
squamosum et conchis evolvens corporis agmen...