Braulioceras is a smooth,

orthoconic An orthocone is the long, cone-shaped shell belonging to several species of ancient nautiloid cephalopod—the prehistoric ancestors of today's marine cephalopod mollusks, including the cuttlefishes, nautiluses, octopuses and squids.; During the ...

orthocerid Orthocerida, from Ancient Greek ὀρθός (''orthós''), meaning "straight", and κέρας (''kéras''), meaning "horn", also known as the Michelinocerida, is an order of extinct orthoceratoid cephalopods that lived from the Early Ordovician ...

with very close spaced

septa SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people througho ...

(around 8 over a length equal to the diameter of the shell) added to the Sactorthoceratidae in 2007. The type species, ''Braulioceras sanjuanense'' comes from the Middle

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

of the San Juan Formation, Argentine

Precordillera Precordillera is a Spanish geographical term for hills and mountains lying before a greater range, similar to foothills. The term is derived from ''cordillera'' (mountain range)—literally "pre-mountain range"—and applied usually to the Andes. ...

. ''Braulioceras'' is very similar to '' Sactorthoceras''. The

siphuncle The siphuncle is a strand of biological tissue, tissue passing longitudinally through the mollusc shell, shell of a cephalopod mollusc. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the li ...

is central, with orthochoanitic septal necks and segments which are slightly expanded between septa, giving it a beaded appearance. The thickness of the connecting rings is similar to that in ellesmerocerids. Endosiphuncular or cameral deposits are unknown. ''Braulioceras'' is distinguished from ''Sactorthoceras'' by its more closely central siphuncle, and expanded segments without the contractions at the ends as in the type species of ''Sactorthoceras'', ''S. gonioseptatum''.

References

Paleobiology-db Braulioceras
*B. Kröger, et al. 2007. Early orthoceratoid cephalopods from the Argentine Precordillera (Lower-Middle Ordovician). Journal of Paleontology 81(6):1266-128

* Rousseau Flower, 1962. Notes on the Michelinoceratida. Memoir 10, Part II, p. 30. New Mexico Bureau of Mines and Mineral Resources. Nautiloids Ordovician Argentina {{paleo-cephalopod-stub