Is this a tenor clef?

My wind band is playing Saint-Saens' Pas Redouble, using the Josneau arrangement published by Evette & Schaeffer. It's on IMSLP. The bassoon part is mostly in bass clef, but occasionally uses a clef I've never seen before. I assume it's a variation of a C (tenor) clef. You can see it after the 8 bar rest below.

Stanford and Forsyth showed the historical evolution of the tenor clef in this image (found here).

Does anyone have a more authoritative source confirming that this is a tenor clef?

It would be conclusive if there were a key signature shown in that clef, but in this piece, the key signature is shown in bass clef only. Tenor clef would mean e-natural and f-sharp accidentals, which seems quite reasonable.

• One way to confirm your hypothesis would be to check the score (if you have access to it, of course) to see whether the part makes sense if you assume that the clef is a tenor clef. But also note that this clef is shown fourth from the end on the first line of Stanford and Forsyth, and second on the second line. Feb 19, 2023 at 16:51
• I find the given reference lacking; in my opinion it does not convey, that the C clef is called a tenor clef only, when sitting on the fourth line (counted from below). Feb 20, 2023 at 12:11

Preface: Tenor clef (nor any other clef) does not change the key signature, only the lines and/or spaces on which the key signature appears.

Yes, it's a tenor clef. The "authoritative source" is the score itself.

The clef appears at m. 15.

Looking at the conductor's score (transposed to Bb — i.e., one whole step above concert pitch), the band at that moment is playing a C major chord: first as `C3 C4 E4` then as `G2 C4 E4`.

Thus, at concert pitch, the band is playing a Bb major chord, and the bassoon, being a non-transposing instrument — should be playing a pitch within the chord: `Bb` or `D`. Looking only at that single measure, the clef could be tenor or alto, and the bassoon would be "in the chord".

The clef appears again at m. 55. The conductor's score at that point shows an F major chord followed by F# diminished. Note in particular the "bass" part (in treble clef) moving chromatically from F to F# (Eb to E natural in concert pitch).

The bassoon part only makes sense if it is also Eb to E natural. So the clef must be a tenor clef. (In alto clef, it would be G to G#, which would clash horribly with the rest of the band.)

This is further confirmed by Saint-Saens's own arrangement for piano, 4 hands. Between the secondo and primo parts, there are an Eb major chord `Eb3 G5 Bb5` followed by an E diminished chord `E3 G5 Bb5`. The only moving part being Eb to E means that the wind-band bassoon part also can only be Eb to E.

It looks like one of those old style C-clefs, and is centred about the 4th line — it's a tenor clef.

This is the Bariton clef: c clef on the 5th line.

Because it is equivalent to the F-clef on the third line, the C-clef on the fifth line version of the baritone clef is a rarity.

Source:

Symbols.com