Jovellania
Encyclopedia
Jovellania is an extinct prehistoric nautiloid genus from the order Oncocerida
known from the Lower Devonian
of Europe (France, Germany). Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera.
Jovellania was named by Bayle (1879) and is type genus for the Jovellaniidae
, a family assigned to the Oncocerida by Flower (1950)
The ventrolateral sides are flattend causing the prosiphuncular (ventral) side to be slightly angular. Septa are closely speced and sutures are transverse. The siphuncle
is positioned between the center and the ventral margin and closer to the margin ; segments are expanded into the chambers; actinosiphonate deposits consist of longitudinal lamellae
Oncocerida
The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian ,in which the connecting rings are thin and siphuncle segments are variably expanded...
known from the Lower Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
of Europe (France, Germany). Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera.
Jovellania was named by Bayle (1879) and is type genus for the Jovellaniidae
Jovellaniidae
Jovellaniidae was established as a family within the Oncocerida to include genera characterized by longiconic orthocones and cyrtocones with a subtriangular to depressed cross-section in which the ventral side is typically angular or more acutely rounded than the dorsal side, and in which the...
, a family assigned to the Oncocerida by Flower (1950)
Morphology
Jovellania can be described as having a slowely widening, straight or slightly cytoconic shell with faint undulations and nearly circular or slightly depressed cross-sectionThe ventrolateral sides are flattend causing the prosiphuncular (ventral) side to be slightly angular. Septa are closely speced and sutures are transverse. The siphuncle
Siphuncle
The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and Spirula...
is positioned between the center and the ventral margin and closer to the margin ; segments are expanded into the chambers; actinosiphonate deposits consist of longitudinal lamellae
See also
- NautiloidNautiloidNautiloids are a large and diverse group of marine cephalopods belonging to the subclass Nautiloidea that began in the Late Cambrian and are represented today by the living Nautilus. Nautiloids flourished during the early Paleozoic era, where they constituted the main predatory animals, and...