Syringonautilidae

The Syringonautilidae are characterized by generally involute shells - early whorls are in view - with broadly to sharply rounded whorl sections and smooth surfaces, except for growth lines and fine wire-like lirae in some forms. The siphuncle is variable in position, and the suture is variably sinuous.^[2]

Five genera are described in the Treatise, Syringonautilus, Clymenonautilus, Juvavionautilus, Oxynautilus, and Syringoceras. Syringonautilus and Syringoceras are known from both the Middle and Upper Triassic; Clymenonautilus, Juvavionautilus, and Oxynautilus only from the Upper Triassic.^[3]

Syringonautilus,^[4] which has been found in the Alps, on Spitsbergen, in India and Japan has a rapidly expanding evolute shell with a perforate umbilicus and suboval whorl section. The suture has a faint ventral saddle and shallow lateral lobes. The siphuncle is subcentral. The surface is ornamented with fine lirae. Syringoceras,^[5] found in Europe, on the island of Timur in Indonesia, and in western North America (Calif and Nev) is like Syringonautilus except that the siphuncle is near marginal.

Clymenonautilus,^[6] first of the strictly Upper Triassic genera, is evolute with a perforate umbilicus and deep dorsal impression when the whorl envelops a third of the previous. The whorl section is higher than wide with flattened flanks and rounded ventral and umbilical shoulders. The suture is transverse across the venter and has deep, tongue-like lobes on either side. The inner whorls are covered with fine lirae, and the outer ones are smooth. The position of the siphuncle is unknown. Clymenoceras comes from Europe.

Juvavionautilus,^[6] has a widely umbilicate, slowly expanding, evolute, perforate shell in which the flanks converge on a rounded to flattened venter so that the maximum width is just central of the umbilical shoulders. The suture includes a ventral saddle and broad lateral lobes. In some, there is a secondary ventral lobe. The siphuncle is subcentral. Juvavionautilus comes from Europe and Timur.

Oxynautilus,^[5] differs from the rest in that it has an involute, compressed lenticular shell with a narrow or acute (angular) venter which may or may not have a keel. The whorl section is much higher than wide with the maximum width slightly ventral of the umbilical shoulders. The suture is sinuous, including a narrowly rounded to angular ventral saddle and broad lateral lobes. The siphuncle is subcentral. Oxynautilus has been found in Europe in the Alps, in California in North America and in the Payandé Formation in Tolima, Colombia.^[7]

Discover more about Genera related topics

Spitsbergen

Spitsbergen

Spitsbergen is the largest and the only permanently populated island of the Svalbard archipelago in northern Norway.

Umbilicus (mollusc)

Umbilicus (mollusc)

The umbilicus of a shell is the axially aligned, hollow cone-shaped space within the whorls of a coiled mollusc shell. The term umbilicus is often used in descriptions of gastropod shells, i.e. it is a feature present on the ventral side of many snail shells, including some species of sea snails, land snails, and freshwater snails.

Timur

Timur

Timur or Tamerlane, later Timūr Gurkānī was a Turco-Mongol conqueror who founded the Timurid Empire in and around modern-day Afghanistan, Iran, and Central Asia, becoming the first ruler of the Timurid dynasty. An undefeated commander, he is widely regarded as one of the greatest military leaders and tacticians in history, as well as one of the most brutal. Timur is also considered a great patron of art and architecture as he interacted with intellectuals such as Ibn Khaldun, Hafez, and Hafiz-i Abru and his reign introduced the Timurid Renaissance.

Tolima Department

Tolima Department

Tolima is one of the 32 departments of Colombia, located in the Andean region, in the center-west of the country. It is bordered on the north and the west by the department of Caldas; on the east by the department of Cundinamarca; on the south by the department of Huila, and on the west by the departments of Cauca, Valle del Cauca, Quindío and Risaralda. Tolima has a surface area of 23,562 km2, and its capital is Ibagué. The department of Tolima was created in 1861 from a part of what was previously Cundinamarca.

Colombia

Colombia

Colombia, officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuela to the east and northeast, Brazil to the southeast, Ecuador and Peru to the south and southwest, the Pacific Ocean to the west, and Panama to the northwest. Colombia is divided into 32 departments. The Capital District of Bogotá is also the country's largest city. It covers an area of 1,141,748 square kilometers, and has a population of around 52 million. Colombia's cultural heritage—including language, religion, cuisine, and art—reflects its history as a Spanish colony, fusing cultural elements brought by immigration from Europe and the Middle East, with those brought by enslaved Africans, as well as with those of the various Indigenous civilizations that predate colonization. Spanish is the official state language, although English and 64 other languages are recognized regional languages.

Fossils of Syringonautilidae have been found in Austria, China, Colombia, Hungary, Italy, the Russian Federation, and the United States (California, Nevada).^[8]