6-457: † Aturiidae † Cymatoceratidae † Hercoglossidae † Paracenoceratidae † Pseudonautilidae Nautilidae The Nautilaceae form one of five superfamilies that make up the Nautilida according to Bernard Kummel (1964), and the only one that survived past the Triassic . The Nautilaceae comprise six families: Nautilidae , Paracenoceratidae , Pseudonautilidae , Cymatoceratidae , Hercoglossidae , and Aturiidae . Shimanskiy (1957) separated
12-462: A monotypic family, established by Campman in 1857 for Aturia Bronn, 1838, and is included in the superfamily Nautilaceae in Kümmel 1964. Aturia is characterized by a smooth, highly involute, discoidal shell with a complex suture and subdorsal siphuncle . The shell of Aturia is rounded ventrally and flattened laterally; the dorsum is deeply impressed. The suture, one of the most complex in
18-592: A small siphuncle. Some groups have sinuous plications or ribs. The Nautilaceae began in the Late Triassic with Cenoceras , a globular to discoidal genus derived from the Syringonautilidae and possibly from Syringonautilus . Cenoceras , the earliest member of the Nautilaceae and Nautilidae, is the only nautiloid known to have crossed the upper Triassic boundary and the only one known from
24-527: The Nautiloidea , has a broad flattened ventral saddle, narrow pointed lateral lobes, broad rounded lateral saddles, broad lobes on the dorso-umbilical slopes, and a broad dorsal saddle divided by a deep, narrow median lobe. The siphuncle is moderate in size and located subdorsally in the adapical dorsal flexture of the septum. Based on the feeding and hunting behaviors of living nautiluses, Aturia most likely preyed upon small fish and crustaceans . Aturia
30-811: The Lower Jurassic. All six families of the Nautilaceae, except for the Aturiidae ( Aturia ), are derived from the Cenoceras complex in the Middle Jurassic or from Eutrephoceras which immediately followed. The Cenozoic Aturia seems sufficiently derived to warrant familial distinction from its source, the Hercoglossidae. Aturiidae Aturia is an extinct genus of Paleocene to Miocene nautilids within Aturiidae ,
36-653: The Paracenoceratidae and Pseudonautilidae from his near equivalent Nautilina and added them to the Lyroceratina , expanding the equivalent Clydonautiloidea and bringing it into the Jurassic. The Nautilaceae are represented by Nautilus and Allonautilus , genera included in the Nautilidae. Species in the Nautilaceae are generally smooth and involute with straight to strongly sinuous sutures and
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