|
Hoko River Formation
The Hoko River Formation is a Late Eocene marine sedimentary geologic formation. The formation is exposed in outcrops along the Strait of Juan de Fuca on the Olympic Peninsula in Washington state, USA. It is known for containing numerous fossils of crabs. It overlies the older Lyre Formation and underlies the younger Makah Formation. Geology and stratigraphy The Hoko River Formation consists of sediments deposited on the inner and middle slopes of a deep marine fan system. It is composed primarily of siltstones and some sandstones exposed under and to the south of the main Makah Formation outcrops along the Strait of Juan De Fuca. The type section, as designated by Parke Snavely ''et al.'', is a section which outcrops along the Hoko River, for which the formation is named, and a section which outcrops along Deep Creek. While the Hoko River formation overlies the Lyre Formation in many places, the two formations intertongue in others. The Makah and Hoko River format ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branchioplax
''Branchioplax'' is an extinct genus of crab which existed in Alaska and Washington during the Eocene period. It was first named by Mary Rathbun in 1916, and contains ten species, including ''Branchioplax washingtoniana'' from the Hoko River Formation, ''Branchioplax carmanahensis'', and ''Branchioplax ballingi''.Page 319, ''Bulletin de la Société géologique de France'', Société géologique de France, 1959. References External links The Family Goneplacidae MacLeay, 1838 (Crustacea: Decapoda, Brachyura): systematics phylogeny and fossil records.''Branchioplax''at the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Pale ... Crabs Eocene crustaceans Eocene arthropods of North America Fossil taxa described in 1916 Taxa named by Mary J. Rathbun {{cra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoko River
The Hoko River is a river in the U.S. state of Washington. It originates in the foothills of the Olympic Mountains, and runs about to the Pacific Ocean through a rugged landscape that has been heavily logged. Its largest tributary is the Little Hoko River, which joins at river mile . The lower of the Hoko River is estuarine. The Hoko watershed supports chinook, chum, coho, and winter steelhead, with over of stream miles that provide suitable spawning habitat. Because the Hoko River, like the nearby Pysht River, is brushy, full of snags, and often carries tannin stained water, it is known as a "cedar creek". The name Hoko is of Makah origin and refers to the large projecting rock at the river mouth. The Hoko River is the namesake of the Late Eocene Hoko River Formation, which was formally described in 1976 by Parke D. Snavely, Jr. et al from outcrops along the river. Sites along the Hoko River have proved it to be an ideal location for preserving artifacts, bones, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portunidae
Portunidae is a family of crabs which contains the swimming crabs. Description Portunid crabs are characterised by the flattening of the fifth pair of legs into broad paddles, which are used for swimming. This ability, together with their strong, sharp claws, allows many species to be fast and aggressive predators. Examples Its members include many well-known shoreline crabs, such as the European shore crab (''Carcinus maenas''), blue crab (''Callinectes sapidus''), and velvet crab ('' Necora puber''). Two genera in the family are contrastingly named ''Scylla'' and ''Charybdis''; the former contains the economically important species black crab (''Scylla serrata'') and ''Scylla paramamosain''. Taxonomy The circumscription of the family varies, with some authors treating "Carcinidae", "Catoptridae" and "Macropipidae" as separate families, and others considering them subfamilies of a wider Portunidae. Swimming crabs reach their greatest species diversity in the Pacific and Indian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Record
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. They first appeared during the Jurassic Period. Description Crabs are generally covered with a thick exoskeleton, composed primarily of highly mineralized chitin, and armed with a pair of chelae (claws). Crabs vary in size from the pea crab, a few millimeters wide, to the Japanese spider crab, with a leg span up to . Several other groups of crustaceans with similar appearances – such as king crabs and porcelain crabs – are not true crabs, but have evolved features similar to true crabs through a process known as carcinisation. Environment Crabs are found in all of the world's oceans, as well as in fresh w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus Praepompilius
''Nautilus praepompilius'' is an extinct species of nautilus. It lived from the Late Paleocene through Oligocene epochs. The first fossil specimens discovered in the Late Eocene to Oligocene-aged Chegan Formation of Kazakhstan: an additional, older specimen was found in the Late or Latest Paleocene-aged Pebble Point Formation in Victoria, Australia.Ward, P. D., et al. "The Paleocene cephalopod fauna from pebble point, Victoria (Australia)-fulcrum between two Eras." (2016): 391. ''N. praepompilius'' has been grouped into a single genus together with extant species based on their shared shell characters. It is morphologically closest to '' N. pompilius'', hence the name. The nepionic constriction shows that the hatching size was approximately 23 mm, close to that for ''N. pompilius'' (around 26 mm).Ward, P.D. & W.B. Saunders 1997''Allonautilus'': a new genus of living nautiloid cephalopod and its bearing on phylogeny of the Nautilida ''Journal of Paleontology'' 71(6): 1054 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belosaepiidae
Belosaepiidae is an extinct family of cephalopods known from the Eocene epoch, and bearing close similarity to the sepiid cuttlefish, whilst retaining the remnants of a belemnite Belemnitida (or the belemnite) is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most ...-like guard. It is thought that this species was most common for its time. References Eocene animals {{cuttlefish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aturia
''Aturia'' is an extinct genus of Paleocene to Miocene nautilids within Aturiidae, a monotypic family, established by Campman in 1857 for ''Aturia'' Bronn, 1838, and is included in the superfamily Nautilaceae in Kümmel 1964. ''Aturia'' is characterized by a smooth, highly involute, discoidal shell with a complex suture and subdorsal siphuncle. The shell of ''Aturia'' is rounded ventrally and flattened laterally; the dorsum is deeply impressed. The suture, one of the most complex in the Nautiloidea, has a broad flattened ventral saddle, narrow pointed lateral lobes, broad rounded lateral saddles, broad lobes on the dorso-umbilical slopes, and a broad dorsal saddle divided by a deep, narrow median lobe. The siphuncle is moderate in size and located subdorsally in the adapical dorsal flexture of the septum. Based on the feeding and hunting behaviors of living nautiluses, ''Aturia'' most likely preyed upon small fish and crustaceans. ''Aturia'' is likely derived from species of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilus Cookanum
''Nautilus cookanum'' is an extinction, extinct species of nautilus. It lived during the Eocene Epoch (geology), epoch. ''N. cookanum'' placed within the genus ''Nautilus'', together with extant species based on their shared shell characters.Ward, P.D. & W.B. Saunders 1997''Allonautilus'': a new genus of living nautiloid cephalopod and its bearing on phylogeny of the Nautilida ''Journal of Paleontology'' 71(6): 1054–1064. Fossils of the species from the Late Eocene Hoko River Formation are noted as one of the two oldest occurrences for the genus (with the other, older occurrence being ''Nautilus praepompilius, N. praepompilius'' of the Paleogene). References Prehistoric nautiloids Nautiluses Eocene molluscs Eocene animals of North America Fossil taxa described in 1892 {{paleo-Nautiloidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Crab")
