ABSENCE of jaw teeth of any kind has been considered a familial character in pipefishes (Syngnathidae)1–3, and their feeding mode has generally been described as a picking or sucking process resulting from rapid intake of water through the elongate snout4,5. During systematic studies of Indo-Pacific syngnathids, we have found toothlike processes on the premaxillae and dentaries in three genera of abdominal-pouch pipefishes (Gastrophori). These structures (Fig. 1) are best developed in Choeroichthys sculptus (Gunther) and C. brachysoma (Bleeker) where they are readily seen under ×30 magnification in all subadults and adults. In Syngnathoides Bleeker (dentaries only) and a newly described genus6, they are inconspicuous, and best seen in cleared and alizarin-stained material.