Question: how are syllabic consonants indicated in transcription?
Answer: It is said to be a syllabic consonant, and we use a special notation to transcribe it: [ɹɪðm̩]. Look at that little vertical line below the [m] symbol — that's called a diacritic. ... That vertical line is the diacritic for a syllabic consonant. Here's an example of a liquid consonant becoming syllabic.