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Trocholites is a tarphycerid genus in the family Trocholitidae from the Middle and Late Ordovician with a gradually expanding, weakly ribbed shell; whorls in contact, dorsum slightly impressed; cross section depressed, venter and sides rounded; siphuncle close to but not at the dorsal margin.
Discoceras is an extinct marine cephalopod mollusk, a member of the Trocholitidae in the Tarphycerida. It is distinct from Discosorus, It is characterized by closely coiled, gradually expanding shells with a subquadrate cross section, that may be ribbed or smooth. The sides are broadly rounded; the venter is wide and slightly rounded. The maximum width is slightly dorsal of the middle. The dorsum has a slight to moderate impression. The siphuncle starts off central for the first half whorl then becomes marginodorsal in the succeeding two whorls, then subdorsal at maturity. As with Trocholites, the dorsal siphuncle in Discoceras probably indicates an orientation during life that places the back of the living chamber high in the shell.
Chrysomallon squamiferum, commonly known as the scaly-foot gastropod, scaly-foot snail, sea pangolin, or volcano snail is a species of deep-sea hydrothermal-vent snail, a marine gastropod mollusc in the family Peltospiridae. This vent-endemic gastropod is known only from deep-sea hydrothermal vents in the Indian Ocean, where it has been found at depths of about 2,400–2,900 m (1.5–1.8 mi). C. squamiferum differs greatly from other deep-sea gastropods, even the closely related neomphalines. In 2019, it was declared endangered on the IUCN Red List, the first species to be listed as such due to risks from deep-sea mining of its vent habitat.
Gonioceras is an extinct genus of actinocerid nautiloidean cephalopods typified by a broad, low shell; flattened ventrally, convexly rounded dorsally; top and bottom meeting at an acute angle along the sides. In most the shell is rather thin, especially along the lateral portion. The aperture is contracted. Sutures from broad ventral and dorsal lobes, more narrowly rounded ventro-lateral and dorso-lateral saddles, and sharp pointed lateral lobes; more complex than in later Lambeoceras. The siphuncle is typically subcentral but may be closer to the venter; armenocerid in form with short segments and very short brims and containing a straight endosiphuncular canal system.
Slender Oncoceratidae are those in the family Oncoceratidae, which have slender, commonly curved, shells. Some like Oocerina are gently curved, almost straight, and with only slight expansion. Others like Dunleithoceras are strongly curved with a more notable rate of expansion. Inclusion in this somewhat arbitrary category is based on illustrations in the Treatise Part K, 1964.
The Trocholitidae are Tarphycerida with whorls in close contact as with the Tarphyceratidae, but in which the siphuncle, similar in structure, becomes dorsal. The Trocholitidae are derived from the Tarphyceratidae, perhaps from different tarphyceratids.
Paraloxoceras is a genus of straight shelled, orthoconic nautiloid cephalopods, now extinct, that lived during the Early Carboniferous. Fossils have been found in Europe and central Asia; the type, P. konincki, named by Flower, came from Belgium.
Osbornoceras is a genus of Lower Silurian cyrtoconic nautiloid cephalopods known from Ohio and possibly Manitoba, one of five general currently included in the oncocerid family Karoceratidae.
Neocycloceras is an extinct genus of nautiloid included in the Pseudorthocerida that lived during the Late Devonian and Mississippian. Neoclycloceras is characterized by a slender, generally circular shell with slightly oblique, sinuous surficial annulations. Its sutures have dorsal and ventral saddles and lateral lobes and become more oblique with age. Saddles point forward, lobes to the rear. Dorsal saddles are broad and low but the ventral ones are high and conspicuous. The siphuncle is located between the center and venter and is nummuloidal, composed of rounded expanded segments, the inside of which contains a continuous laminar lining that is thickest in the middle of the segments and thinnest at the septal necks. Neocycloceras has been found in Pennsylvania in North America and in Morocco in north Africa.
The Clydonautiloidea are 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. Where known, the siphuncle tends to be central to subcentral.
The Phragmoceratidae is a family of extinct nautiloid cephalopods from the Order Discosorida that lived during the latter part of the Silurian.
Syringonautilidae is a family of Nautiloidea from the middle to late Triassic. Syringonautilidae comprise the last of the Trigonoceratoidea and are the source for the Nautilaceae which continued the Nautiloidea through the Mesozoic and into the Cenozoic right down to the recent. Syringonautilidae is a strictly Triassic family, derived early in the Triassic from the Grypoceratidae.
Grypoceratidae is the longest-lived family of the Trigonoceratoidea, or of the near equivalent Centroceratina; members of the Nautilida from the Upper Paleozoic and Triassic.
The Centroceratidae is the ancestral family of the Trigonoceratoidea and of the equivalent Centroceratina; extinct shelled cephalopods belonging to the order Nautilida
Mandaloceratidae is a family in the nautiloid cephalopod order Discosorida, from the Middle and Upper(?) Silurian characterized by short, essentially straight shells referred to as breviconic, typically with a faintly exogastric shape produced by the profile of the body chamber.
Ophioceras is a genus of closely coiled tarphycerid nautiloid cephalopods, the sole representatives of the family Ophidioceratidae, characterized by an evolute shell with narrow, subrounded, annulated whorls and a subcentral siphuncle composed of thin connecting rings that show no evidence of layering. The mature body chamber is strongly divergent and is the longest proportionally of any tarphycerid. The aperture has a deep hyponomic sinus and ocular sinuses, and so resembles some lituitids.
The Apsidoceratidae is a family of Middle and Upper Ordovician Barrandeocerina,, characterized by curved or coiled, smooth, transversely marked, or laterally costate shells, with a conspicuous hyponomic sinus. Early whorl sections tend to be subtriangular; become broader and dorsally impressed in closely coiled forms. Sutures are with lateral lobes in primitive forms but are without lateral lobes, but with ventral lobes in more advanced species with broader sections. Siphuncles are between the center and ventral margin, but not close to either.
Jiangxisaurus is an extinct genus of oviraptorid theropod dinosaur from the Late Cretaceous Nanxiong Formation of southern China. It was similar to Heyuannia, but with more strongly curved anterior claws and a thinner, frailer mandible. This find is paleontologically significant because it contributes to current knowledge about the paleogeographical distribution of oviraptorids in southern China. It was most likely an omnivorous animal along with its close relatives Nankangia and Ganzhousaurus.
Khunnuchelys was a genus of trionychine turtle from the Late Cretaceous of Asia. Three species are known, K. erinhotensis, the type species, K. kizylkumensis, and K. lophorhothon. K. erinhotensis is known from the Iren Dabasu Formation in China from the late Turonian until the middle Campanian. K. kizylkumensis is known from the late Turonian Bissekty Formation of Uzbekistan. The third species, described in 2013 by Danilov et al., is known from the early to middle Campanian aged Bostobe Formation of Kazakhstan.
Chinlechelys is an extinct genus of stem-turtle belonging to Testudinata. It lived in the Norian age of the Late Triassic and is the oldest turtle known from North America. Among turtles it is unique, mostly because of its very thin shell. The type and only species, C. tenertesta, was named and described with the genus by Walter G. Joyce et al. in 2009. It was probably terrestrial, and was found by Joyce et al. to be closely related to Proganochelys, another terrestrial testudinatan.
References
 | This article may be too technical for most readers to understand.(October 2014) |
- Walter C. Sweet, 1964. Nautiloidea- Barrandeocerida; Treatise on Invertebrate Paleontology. Geological Society of America and University of Kansas Press.