Thrissops Agassiz 1833

GenusThrissopsAgassiz, 1833 Type species. Thrissops formosus Agassiz, 1833. Type horizon and locality. Late Kimmeridgian; Kelheim, Bavaria, Germany. Diagnosis of the genus (amended from Nybelin 1964; Bardack 1965; Alvarado-Ortega and Brito 2010): Elongate, slender or fusiform fishes known to reach a standard length of up to 0.9 m; head length included 4–6.5 times in standard length; mouth cleft directed upward; premaxillary teeth longer than those of maxillary and stoutly conical; triangular lower jaw; mandible without enlarged coronoid process; vertical and horizontal arms of preoperculum form right angle at posteroventral corner; preopercle with well-developed posteroventral process; tubules of preopercular sensory canal confined to horizontal arm of preoperculum; parietals not fused; dorsal fin posterior to anal fin origin; 13–15 dorsal pterygiophores; 23–31 anal pterygiophores; six elongated uroneurals; one urodermal. Distribution. In the late Kimmeridgian and early Tithonian of England, France, and Germany.