Meaning of curved line shape distribution in t-SNE plot
From my own experience, if you have curved lines in your t-SNE plots, it usually implies your original data are scattered similarly in lines as well. One thing you can confirm whether this hypothesis is correct is that you can do principle component analysis (PCA) on your original data and then plot the first two dimensions. Usually, this plot will also be in curved lines.

Your explanation is plausible. However, you suggest you plot your first two PCA components to see what is really going on in your data.