The Trigonoceratoidea are a superfamily within the
Nautilida
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 ''Allonauti ...
that ranged from the
Devonian
The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...
to the
Triassic
The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...
, thought to have contained the source for the
Nautilaceae
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, Pseudonautili ...
in which ''
Nautilus
A nautilus (; ) is any of the various species within the cephalopod family Nautilidae. This is the sole extant family of the superfamily Nautilaceae and the suborder Nautilina.
It comprises nine living species in two genera, the type genus, ty ...
'' is found.
Trigonoceratoidea are characterized by open-spiraled,
gyroconic, to closed,
nautiliconic shells in which the
Whorl
A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs).
In nature
File:Photograph and axial plane floral diagra ...
section is
quadrate in primitive forms; the
venter typically narrow to acute, the dorsum broad. In some advanced forms, the venter may become concave or broad and rounded, and in some, the surfaces may be strongly
lirate.
Classification and phylogeny
The Trigonoceratoidea are based on the family
Trigonoceratidae
The Trigonoceratidae is a family of coiled nautiloid cephalopods that lived during the period from the Early Carboniferous ( Mississippian) to the Early Permian.
Diagnosis
Trigonoceratidae comprise members of the order Nautilida characterized ...
of
Alpheus Hyatt
Alpheus Hyatt (April 5, 1838 – January 15, 1902) was an American zoologist and palaeontologist. Hyatt served as the founding president of the American Society of Naturalists from 1883 to 1884 and was the founding editor of the journal '' T ...
, 1884, with which other
phylogenetic
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
ally related families are combined, and are equivalent to the abandoned Centroceratida of Flower in Flower and Kümmel 1950, and to the Centroceratina of
Shimanskiy 1957, revised to the Centrocerataceae, Shimanskiy 1962.
The Trigonoceratoidea combine five families, the type, Trigonoceratidae, along with the
Centroceratidae,
Grypoceratidae,
Permoceratidae, and
Syringonautilidae. Phylogenetic study and age show that the Centroceratidae are the root stock in spite of having been first recognized 16 years after the Trigonoceratidae were first described.
The Centroceratidae gave rise to the Trigonoceratidae and Grypoceratidae in the early
Mississippian, while continuing until the very
Early Permian 01 or 01 may refer to:
* The year 2001, or any year ending with 01
* The month of January
* 1 (number)
Music
* '01 (Richard Müller album), ''01'' (Richard Müller album), 2001
* 01 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011
* ''01011 ...
. The Trigonoceratidae which ranged into the Permian left no descendants. The Grypoceratidae which ranged almost to the end of the Triassic gave rise to two small families, the Permian Permoceratidae and the Triassic Syringonautilidae. The Syringonautilidae, in turn, are the source for the Nautilidae (Nautilaceae) which contain the genus ''Nautilus''.
Families
The
Trigonoceratidae
The Trigonoceratidae is a family of coiled nautiloid cephalopods that lived during the period from the Early Carboniferous ( Mississippian) to the Early Permian.
Diagnosis
Trigonoceratidae comprise members of the order Nautilida characterized ...
, type family, named by Hyatt, 1884, are loosely coiled to
evolute
In the differential geometry of curves, the evolute of a curve is the locus (mathematics), locus of all its Center of curvature, centers of curvature. That is to say that when the center of curvature of each point on a curve is drawn, the result ...
, with oval to
subquadrate, compressed to depressed whorl sections, and generally with longitudinal ridges or
lirae.
Sutures are typically slightly sinuous; 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 ...
small, subcentral, and
orthochoanitic. In all the
umbilicus is open and perforate. It includes some 17 genera.
The
Centroceratidae, ancestral stock, proposed by Hyatt in 1900, consist of gyroconic to evolute and involute shells that have a quadrangular cross section in which the venter is much narrower that the dorsum, the venereal and umbilical shoulders usually angular, the flanks flattened and converging on the venter. Sutures form lobes on the sides and venter but are transverse across the dorsum. The siphuncle is tubular,
orthochoanitic, and close to but not on the ventral margin. It includes some six genera.
The
Grypoceratidae, predominant stock, established by Hyatt in 1900, are characterized by generally smooth, compressed, evolute to
involute
In mathematics, an involute (also known as an evolvent) is a particular type of curve that is dependent on another shape or curve. An involute of a curve is the Locus (mathematics), locus of a point on a piece of taut string as the string is eith ...
shells with the venter flattened to
subangular. Ornamenation is not common, but some forms bear nodes or keels. Sutures have distinct ventral and lateral lobes. The siphuncle, which is narrow and tubular, is variable in position. It includes about 13 genera.
Shimanskiy separated the Domatoceratidae, typified by the Permian ''
Domatoceras'', from the Grypoceratidae in the Treatise,
[Kümmel, B, 1964; __ Nautilida; Treatise on Invertebrate Paleontology Part K Nautiloidea; Geological Society of America and University of Kansas Press.
*Teichert, C & Moore, R.C 1964; Classification and Stratigraphic Distribution ( Endoceratoidea - Actinoceratoidea -Nautiloidea) ibid.] leaving the Grypoceratidae for mostly earlier forms.
The
Permoceratidae, Permian offshoots named by Miller and Collinson in 1953 for the genus ''
Permoceras'', are involute, smooth, with a compressed, higher than wide, whorl section, ventrally subcentral siphuncle, and a suture with a deep, narrow, pointed ventral lobe and large pointed lateral lobes, mimicking contemporary
goniatites
''Goniatites'' is a genus of extinct cephalopods belonging to the family Goniatitidae, included in the superfamily Goniatitaceae. ''Hibernicoceras'' and ''Hypergoniatites'' are among related genera.
Species
Description
The shell is generally ...
.
The
Syringonautilidae, Triassic offshoots named by
Johann August Georg Edmund Mojsisovics von Mojsvar
Johann August Georg Edmund (Ödön) Mojsisovics von Mojsvár (18 October 18392 October 1907) was an Austro-Hungarian geologist and palaeontologist.
Biography
Mojsisovics was born in Vienna as the son of a Hungarian surgeon Georg (György) Mojs ...
, 1902, gave rise to the Nautilaceae (
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 ...
); containing five genera, they have generally smooth, involute shells with slightly sinuous sutures and a variably positioned siphuncle.
References
Further reading
*Flower, R.H and Kümmel, B. 1950; A Classification of the Naulioidea; Journal of Paleontology, V 24, no 5. pp604–616, Sept 1950
*Flower, R.H. 1988; Progress and Changing Concepts in Cephalopod and Particularly Nautiloid Phylogeny and Distribution, in Cephalopods, Present and Past, pp 17–24, Wiedmann, J, & Kullmann, J (Eds).
{{Taxonbar, from1=Q33187748, from2=Q7841807
Nautiloids
Late Devonian first appearances
Late Devonian animals
Late Triassic extinctions