24-571: Hercoglossidae is a family of nautilid cephalopods in the superfamily Nautilaceae . It was established by Spath in 1927 for smooth, involute nautiloids characterized by a suture with differentiated elements, known from the Upper Jurassic to the Oligocene. Four genera are described in the Treatise. They are Hercoglossa , Aturoidea , Cimonia , and Deltoidonatilus . All have
48-484: 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 . The current classification of
72-818: A second decline after the Middle Silurian. After this the order declined until its extinction in the Early Carboniferous ( Mississippian ). Near the beginning of the Devonian and well before its end, the Oncocerida gave rise to the Rutoceratidae (Flower, 1976; Kümmel, 1964), which form the root stock of the Nautilida , which among its members includes the modern Nautilus and Allonautilus . Oncocerids are well known as fossils from
96-599: A whorl section that is generally rounded, except for Deltoidonatilus where in it is triangular in outline. Sutural complexity increases from Cimomia to Hercoglossa and to Aturoidea . The suture in Deltoidonautilus is like than in Hercoglossa . Cimomia , which intergrades with Eutrephoceras , is the earliest and makes its first appearance in the Upper Jurassic . Eutrephoceras is assigned to
120-727: Is an abridged version of Shimansky's and Flower's early schemes. Both Shimansky and Kummel derive the Nautilida from the Oncocerida with either the Acleistoceratidae or Brevicoceratidae (Teichert 1988) which share some similarities with the Rutoceratidae as the source. The Rutoceratidae are 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
144-601: The Nautilidae which includes Nautilus . Hercoglossa , which is derived from Cimomia , first appears in the Lower Cretaceous and is followed stratigraphically by Aturoidea and Deltoidonautilus which first appear in the Upper Cretaceous. Aturoidea is the progenitor of Aturia (of the monotypic Aturidae), to which it gave rise in the Paleocene. Nautilida The Nautilida constitute
168-685: 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 goniatites . 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
192-539: 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
216-839: 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 are now abandoned. Within the Nautilida, he placed 10 families, included in the Nautilaceae and the no longer considered ancestral Clydonautilaceae. Teichert's 1988 classification
240-539: The Bassleroceratidae. Later in the mature stages of early forms and throughout in the more advanced the connecting rings are inflated with cyrtochoanitic septal necks, giving what can be described as a "beaded" or "ellipsoidal" appearance (Sweet, 1964). The Oncocerida are thought to be derived from the Bassleroceratidae through Graciloceras as a result of a thinning of the connecting rings in
264-540: 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) Shimansky 1962 (in Kummel 1964) divided the Nautilida into five suborders,
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#1732787717338288-771: 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 those found in species of living Nautilus , ranging from curved (cyrtoconic), through loosely coiled (gyroconic), to tightly coiled forms, represented by
312-807: 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 include the Nautilidae, with Nautilus . (Kummel 1964) The Nautilida are thought to be derived from either of the oncocerid families, Acleistoceratidae or Brevicoceratidae (Kummel 1964; Teichert 1988), both of which have
336-686: The development of OMZs , preventing nautilids from retreating into deeper water, are also cited as other potential causes of extinction. Oncocerida The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian (early Carboniferous ; one possible member is known from the Early Permian ), in which the connecting rings are thin and siphuncle segments are variably expanded (Flower, 1950). At present
360-421: The different families and genera (Flower, 1950; Sweet, 1964). The siphuncle in the Oncocerida is commonly located at or near the ventral margin. Connecting rings are most commonly thin and structureless but in certain derived forms may become actinosiphonate with inwardly projecting radial lamellae. The juvenile segments in early genera are straight and tubular, with short orthochoanitic septal necks inherited from
384-661: 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
408-621: The later Ordovician, Silurian , and Devonian in North America, Europe, and Australia, and to a lesser extent from parts of Asia, after which the order declined into the Mississippian and reached its end by the Pennsylvanian (late Carboniferous) (Flower, 1976; Sweet, 1964). Families in the Oncocerida, according to the Treatise on Invertebrate Paleontology , follow with the number of genera in each shown in parentheses, along with
432-735: The mostly Paleozoic Centroceratina , Liroceratina , Rutoceratina , and Tainoceratina , and the Mesozoic to recent Nautilina . These include superfamilies which are different from those of Kummel (1964) and of less extent. The Centroceratina are comparable to the Trigonocerataceae, the Liroceratina to the Clydonautilaceae, and the Nautilina to the Nautilaceae. The main difference is that the Rutoceratidae are included with
456-606: The order consists of some 16 families, a few of which, such as the Oncoceratidae, Brevicoceratidae, and Acleistoceratidae contain a fair number of genera each while others like the Trimeroceratidae and Archiacoceratidae are represented by only two or three (Sweet, 1964). The shells of oncocerids are primarily somewhat compressed cyrtoconic brevicones. More advanced forms include gyrocones, serpenticones, torticones, and elongate orthocones and cyrtocones, reflective of
480-678: 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
504-582: 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 such as
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#1732787717338528-579: The siphuncle (Flower, 1976). Oncocerids reached their greatest generic diversity in the Middle Silurian with some 43 genera representing nine families (Sweet, 1964), the most at any time. Of these 43 or so genera, about 38 were new, a recovery from a precipitous decline in the Late Ordovician and Early Silurian . A second period of greater diversity occurred in the Middle Devonian with eight families represented by some 37 genera, following
552-725: The southwest Pacific . The recent decrease in the once worldwide distribution of nautilids is now believed to have been caused by the spread of pinnipeds . From the Oligocene onward, the appearance of pinnipeds in the geological record of a region coincides with the disappearance of nautilids from that region. As a result, nautilids are now limited to their current distribution in the tropical Indo-Pacific ocean, where pinnipeds are absent. The genus Aturia seem to have temporarily survive regions where pinnipeds were present through adaptations to fast and agile swimming, but eventually went extinct as well. Predation by short-snouted whales and
576-561: 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
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