Common names: puffer (English), tamboril (Espanol), cuche (Espanol)
Guentheridia formosa (Günther, 1870)
Body a heavy elongate oval; head low and broad, notably wider than deep; wide and convex between eyes; snout short; nasal organ consists of a low, broad papilla, with 2 large holes and a cluster of small pits on the inside of the papilla; eyes high on sides of head; jaws are a beak composed of 4 fused heavy powerful teeth with a central suture on each jaw; a slit-like gill opening in front of the pectoral fin base; a single short- based dorsal fin at rear of body; a similar-shaped anal fin below the dorsal; no pelvic fins; no spines in the fins; tail fin bluntly straight, with 10 main rays; tough scaleless skin, body with small spinules, no fleshy skin flaps.
Upper half of head and body dark, paler below; with variable yellowish markings: body with spots in patterns ranging from spots back and upper sides with evenly distributed, variably sized (½ eye to > eye), variably spaced dark spots, sometimes spots arranged or nearly united, in concentric circles, with smallest ring in center of back, all gradations between these two patterns occur; tail dusky, other fins greenish. Juveniles - cross lines on head, concentric rings enclosing rings on back, reticulations on sides.
Size: 26 cm.
Habitat: demersal on coastal soft bottoms, common in estuaries.
Depth: 0-10 m.
Costa Rica to Ecuador.