Someone recently called my attention to a hexameter by Lucilius:
Jānus, Quirīnus "pater" siet ac dicātur ad ūnum.
Janus or Quirinus may be "father"; every single [god] is called this.
And there's something a bit odd about this scansion. The second syllable of Jānus has to scan as light, even though it's followed by another consonant. In other words, the final -s before a stop isn't treated as a coda.
This makes sense to me—phonologically, squ- is a valid syllable onset, as in squālor. But I've never seen this sort of syllabification in metered poetry before: normally, s between a vowel and a consonant is treated as a coda (e.g. -us la- in Aeneid I.2).
How common is this? Does it happen in Classical authors too (or really anyone except Lucilius)? And is there a name for it?