Nautilida
Encyclopedia
The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic
and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus
and Allonautilus
, with six species. All told between 22 and 34 families and 165 to 184 genera have been recognised, making this the largest order of the subclass Nautiloidea.
, and Tainoceratina
, and the Mesocoic to Recent Nautilina
. These include superfamilies which are different from those of Kummel (1964) and of less extent. The Centroceratina is comparable to the Trigonocerataceae, the Liroceratina to the Clydonautilaceae, and the Nautilina to the Nautilaceae. The main difference is that the Rutoceratidae is included with the Aipocerataceae of Kummel (1964) in the Rutoceratina. The remaining Tainocerataceae are the Tainoceratina.
Rousseau Flower (1950) distinguished the Solenochilida, Rutoceratida, and Centroceratida, as separate orders, from the Nautilida, derived from the Barrandeocerida which is now abandoned. Within the Nautilida he placed ten families, included in the Nautilaceae and the no longer considered ancestral Clydonautilaceae. Teichert's 1988 classification is an abridged version of Shimansky's and Flower's early schemes.
with either the Acleistoceratidae
or Brevicoceratidae
(Teichert 1988) which share some similarities with the Rutoceratidae
as the source. The Rutoceratidae is the ancestral family of the Tainocerataceae and of the Nautilida (Kummel 1964) and of Shimansky's and Teichert's Rutoceratina.
The Tainocerataceae gave rise probably through the ancestral Rutoceratidae to the Trigonocerataceae and Clydonautiliaceae in the Devonian and to the Aipocerataceae early in the Carboniferous. The Trigonocerataceae in turn gave rise late in the Triassic through the Syringonautilidae to the Nautilaceae which includes the Nautilidae, with Nautilus.(Kummel 1964)
The Nautilida are thought to be derived form either of the oncocerid
families, Acleistoceratidae
or Brevicoceratidae
(Kummel 1964; Teichert 1988), both of which have the same sort of shells and internal structure as found in the Devonian
Rutocerina
of Shimanskiy, the earliest true nautilids. Flower (1950) suggested the Nautilida evolved from the Barrandeocerida, an idea he came later to reject in favor of derivation from the Oncocerida. The idea that the Nautilida evolved from straight-shelled ("Orthoceras
") nautiloids, as proposed by Otto Schindewolf
in 1942, through transitional forms like the Ordovician Lituites
can be rejected out of hand as evolutionarily unlikely. Lituites and the Lituitidae
are derived tarphycerids and belong to a separate evolutionary branch of Nautilioids.
The number of nautilid genera increased from the Early Devonian to about 22 in the Middle Devonian. During this time their shells were more varied than found in species of living Nautilus, ranging from curved (cyrtoconic), through loosely coiled (gyroconic), to tightly coiled forms, represented by the Rutoceratidae
, Tetragonoceratidae
, and Centroceratidae
.
Nautilids declined in the Late Devonian but again diversified in the Carboniferous
when some 75 genera and subgenera in some 16 families are known to have lived. Although there was considerable diversity in form, curved and loosely-coiled shells are rare or absent, except in the superfamily Aipocerataceae
. For the rest, nautilids adapted the standard planispiral shell form, although not all were as tightly-coiled as the modern nautilids (Teichert 1988). There was, however, a great diversity in surface ornamentation, cross section, and so on, with some genera, such as the Permian
Cooperoceras
and Acanthonautilus
, developing large lateral spikes (Fenton and Fenton 1958).
Despite again decreasing in diversity in the Permian, nautilids were less affected by the Permian-Triassic extinction than their distant relatives the Ammonoidea. During the Late Triassic
there was a tendency in the Clydonautilaceae
to develop sutures
similar to those of some Late Devonian goniatite
s. Only a single genus, Cenoceras
, with a shell similar to that of the modern nautilus, survived the less severe Triassic extinction
, at which time the entire Nautiloidea almost became extinct.
For the remainder of the Mesozoic
, nautilids once again flourished, although never at the level of their Paleozoic glory, and 24 genera are known from the Cretaceous
. Again, the nautilids were not as affected by the end Cretaceous mass extinction
as the Ammonoids that became entirely extinct, possibly because their larger eggs were better suited to survive the conditions of that environment-changing event.
Three families and at least five genera of nautilids are known to have survived this crisis in the history of life. There was a further resurgence during the Paleocene
and Eocene
, with several new genera, the majority of which had a worldwide distribution. During the Late Cretaceous and Early Tertiary, the Hercoglossidae and Aturiidae again developed sutures like those of Devonian goniatites. (Teichert 1988, pp.43-44)
Miocene
nautilids were still fairly widespread, but today the order includes only two genera, Nautilus and Allonautilus, limited to the south-west Pacific.
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus
Nautilus
Nautilus is the common name of marine creatures of cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in two genera, the type of which is the genus Nautilus...
and Allonautilus
Allonautilus
The genus Allonautilus contains two species of nautiluses, which differ significantly in terms of morphology from those placed in the sister taxon Nautilus. Allonautilus is now thought to be a descendant of Nautilus and the latter paraphyletic.-External links:*...
, with six species. All told between 22 and 34 families and 165 to 184 genera have been recognised, making this the largest order of the subclass Nautiloidea.
Current classification
The current classifiction of the Nautilida, in prevalent use, is that of Bernhard Kummel (Kummel 1964) in the Treatise which divides the Nautilida into five superfamilies, the Aipocerataceae, Clydonautilaceae, Tainocerataceae, and Trigonocerataceae, mostly of the Paleozoic, and the later Nautilaceae. These include 22 families and some 165 or so genera (Teichert and Moore 1964)Other concepts
Shimansky 1962 (in Kummel 1964) divided the Nautilida into five suborders, the mostly Paleozoic Centroceratina, Liroceratina, RutoceratinaRutocerina
The Rutocertina is one of only three suborders in Shimankiy's classification of the Nautilida, the other two being the Lirocerina and Nautilina. Genera in the Rutocerina are redistributed in the Rutoceratina, Tainoceratina, and Centroceratina. The Lirocerina is redefined as the Liroceratina, and...
, and Tainoceratina
Tainoceratina
For a further discussion of this group as in use today, see the superfamily TainocerataceaeThe Tainoceratina is a suborder within the Nautilida created by Shimanskiy on the assumption that the initial, or embryonic, whorl was the critical phylogenetic indicator, which resulted in combining...
, and the Mesocoic to Recent Nautilina
Nautilina
The Nautilina is the last suborder of the Nautilida and the only nautiloids living since the end of the Triassic. The Nautilina, proposed by Shimanskiy, is basically the Nautilaceae of Kummel, 1964, defined by Furnish and Glenister, but differs in omitting two families, the Paracenoceratidae and...
. These include superfamilies which are different from those of Kummel (1964) and of less extent. The Centroceratina is comparable to the Trigonocerataceae, the Liroceratina to the Clydonautilaceae, and the Nautilina to the Nautilaceae. The main difference is that the Rutoceratidae is included with the Aipocerataceae of Kummel (1964) in the Rutoceratina. The remaining Tainocerataceae are the Tainoceratina.
Rousseau Flower (1950) distinguished the Solenochilida, Rutoceratida, and Centroceratida, as separate orders, from the Nautilida, derived from the Barrandeocerida which is now abandoned. Within the Nautilida he placed ten families, included in the Nautilaceae and the no longer considered ancestral Clydonautilaceae. Teichert's 1988 classification is an abridged version of Shimansky's and Flower's early schemes.
Derivation and evolution
Both Shimansky and Kummel derive the Nautilida from the OncoceridaOncocerida
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...
with either the Acleistoceratidae
Acleistoceratidae
The Acleistoceratidae, named by Flower in Flower & Kümmel 1950, is a family of oncocerids that contains genera characterized by depressed exogastric brevicones and cyrtocones that range from the Middle Silurian to the Middle Devonian...
or Brevicoceratidae
Brevicoceratidae
The Brevicoceratidae, named by Flower in 1941, is a family of oncocerids that contains genera characterized by exogastric gyrocones, brevicones, and torticones that tend to develop vestigial actinosiphonate deposits and subtriangular transverse sections...
(Teichert 1988) which share some similarities with the Rutoceratidae
Rutoceratidae
The Rutoceratidae are the prototypical nautilids, derived probably from either the Brevicoceratidae or Acleistoceratidae of the Oncocerida early in the Devonian...
as the source. The Rutoceratidae is the ancestral family of the Tainocerataceae and of the Nautilida (Kummel 1964) and of Shimansky's and Teichert's Rutoceratina.
The Tainocerataceae gave rise probably through the ancestral Rutoceratidae to the Trigonocerataceae and Clydonautiliaceae in the Devonian and to the Aipocerataceae early in the Carboniferous. The Trigonocerataceae in turn gave rise late in the Triassic through the Syringonautilidae to the Nautilaceae which includes the Nautilidae, with Nautilus.(Kummel 1964)
Diversity and evolutionary history
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...
families, Acleistoceratidae
Acleistoceratidae
The Acleistoceratidae, named by Flower in Flower & Kümmel 1950, is a family of oncocerids that contains genera characterized by depressed exogastric brevicones and cyrtocones that range from the Middle Silurian to the Middle Devonian...
or Brevicoceratidae
Brevicoceratidae
The Brevicoceratidae, named by Flower in 1941, is a family of oncocerids that contains genera characterized by exogastric gyrocones, brevicones, and torticones that tend to develop vestigial actinosiphonate deposits and subtriangular transverse sections...
(Kummel 1964; Teichert 1988), both of which have the same sort of shells and internal structure as found in the 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...
Rutocerina
Rutocerina
The Rutocertina is one of only three suborders in Shimankiy's classification of the Nautilida, the other two being the Lirocerina and Nautilina. Genera in the Rutocerina are redistributed in the Rutoceratina, Tainoceratina, and Centroceratina. The Lirocerina is redefined as the Liroceratina, and...
of Shimanskiy, the earliest true nautilids. Flower (1950) suggested the Nautilida evolved from the Barrandeocerida, an idea he came later to reject in favor of derivation from the Oncocerida. The idea that the Nautilida evolved from straight-shelled ("Orthoceras
Orthoceras
Orthoceras is a genus of extinct nautiloid cephalopod. This genus is sometimes called Orthoceratites. Note it is sometimes misspelled as Orthocera, Orthocerus or Orthoceros ....
") nautiloids, as proposed by Otto Schindewolf
Otto Schindewolf
Otto Heinrich Schindewolf was a German paleontologist who studied the evolution of corals and cephalopods....
in 1942, through transitional forms like the Ordovician Lituites
Lituites
Lituites is an extinct nautiloid genus from the Middle Ordovician and type for the Lituitidae, a tarphycerid family that in some more recent taxonomies has been classified with the orthocerids and listed under the order Lituitida...
can be rejected out of hand as evolutionarily unlikely. Lituites and the Lituitidae
Lituitidae
The Lituitidae is a family of evolved tarphycerids characterized by a long orthoconic section that follows a coiled juvenile portion at the apex, along with a generally tubular siphuncle, which like that of the barrandeocerids is composed of thin connecting rings.-Taxonomic Position:Flower and...
are derived tarphycerids and belong to a separate evolutionary branch of Nautilioids.
The number of nautilid genera increased from the Early Devonian to about 22 in the Middle Devonian. During this time their shells were more varied than found in species of living Nautilus, ranging from curved (cyrtoconic), through loosely coiled (gyroconic), to tightly coiled forms, represented by the Rutoceratidae
Rutoceratidae
The Rutoceratidae are the prototypical nautilids, derived probably from either the Brevicoceratidae or Acleistoceratidae of the Oncocerida early in the Devonian...
, Tetragonoceratidae
Tetragonoceratidae
The Tetragonoceratidae is a small family of nautilitids constituting a part of the superfamily Tainocerataceae in which shells are coiled with a generally quadrate whorl section. Coiling is either gyroconic or evoluute with a slight dorsal impression. Flanks diverge from the umbilical to the...
, and Centroceratidae
Centroceratidae
The Centroceratidae is the ancestral family of the Trigonocerataceae and of the equivalent Centroceratina; extinct shelled cephalopods belonging to the order Nautilida-Diagnosis:...
.
Nautilids declined in the Late Devonian but again diversified in the Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
when some 75 genera and subgenera in some 16 families are known to have lived. Although there was considerable diversity in form, curved and loosely-coiled shells are rare or absent, except in the superfamily Aipocerataceae
Aipocerataceae
The Aipocerataceae is a superfamily within the Order Nautilida characterized by rapidly expanding, smooth to ribbed, cyrtoconic to coiled shells with rounded or sometimes dorsally flattened or impressed whorls, nearly straight sutures, and a ventral and marginal siphuncle. Septal necks are...
. For the rest, nautilids adapted the standard planispiral shell form, although not all were as tightly-coiled as the modern nautilids (Teichert 1988). There was, however, a great diversity in surface ornamentation, cross section, and so on, with some genera, such as the Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
Cooperoceras
Cooperoceras
Cooperoceras is a genus of the Tainoceratidae, which is part of the Tainocerataceae, characterized by and evolute shell with an open, perforate, umbilicus, sinuous ribs at maturity, and recurved hollow spines along the ventro-lateral shoulders. The flanks and venter are flattened, the flanks...
and Acanthonautilus
Acanthonautilus
Acanthonautilus is an extinct genus in the nautilid family Solenochildae from the Upper Mississippian of North America and equivalent strata in Europe, first described by Foord in 1896....
, developing large lateral spikes (Fenton and Fenton 1958).
Despite again decreasing in diversity in the Permian, nautilids were less affected by the Permian-Triassic extinction than their distant relatives the Ammonoidea. During the Late Triassic
Late Triassic
The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...
there was a tendency in the Clydonautilaceae
Clydonautilaceae
The Clydonautilaceae is a superfamily within the nautiloid order Nautilida characterized by smooth, generally globular, shells with nearly straight sutures, in early forms but developing highly differentiated sutures in some later forms...
to develop sutures
Suture (anatomical)
In anatomy, a suture is a fairly rigid joint between two or more hard elements of an animal, with or without significant overlap of the elements....
similar to those of some Late Devonian goniatite
Goniatite
Goniatites are extinct ammonoids, shelled cephalopods related to squid, octopus, and belemnites, that form the order Goniatitida. The Gonatitida originated from within the more primitive anarcestine ammonoids in the Middle Devonian some 390 million years ago...
s. Only a single genus, Cenoceras
Cenoceras
The genus Cenoceras is a member of the Nautilidae, which in turn makes up part of the superfamily Nautilaceae.Cenoceras is variable in form, depending on species; ranges from evolute to involute, compressed lenticular to globose with rounded to flattened venter and flanks. The suture generally has...
, with a shell similar to that of the modern nautilus, survived the less severe Triassic extinction
Triassic-Jurassic extinction event
The Triassic–Jurassic extinction event marks the boundary between the Triassic and Jurassic periods, , and is one of the major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans. In the seas a whole class and twenty percent of all marine families...
, at which time the entire Nautiloidea almost became extinct.
For the remainder of the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
, nautilids once again flourished, although never at the level of their Paleozoic glory, and 24 genera are known from the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
. Again, the nautilids were not as affected by the end Cretaceous mass extinction
Cretaceous-Tertiary extinction event
The Cretaceous–Paleogene extinction event, formerly named and still commonly referred to as the Cretaceous-Tertiary extinction event, occurred approximately 65.5 million years ago at the end of the Maastrichtian age of the Cretaceous period. It was a large-scale mass extinction of animal and plant...
as the Ammonoids that became entirely extinct, possibly because their larger eggs were better suited to survive the conditions of that environment-changing event.
Three families and at least five genera of nautilids are known to have survived this crisis in the history of life. There was a further resurgence during the Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
and Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
, with several new genera, the majority of which had a worldwide distribution. During the Late Cretaceous and Early Tertiary, the Hercoglossidae and Aturiidae again developed sutures like those of Devonian goniatites. (Teichert 1988, pp.43-44)
Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
nautilids were still fairly widespread, but today the order includes only two genera, Nautilus and Allonautilus, limited to the south-west Pacific.