Eoagnostus

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Eoagnostus
Temporal range: terminal Toyonian to early Amgaian (Nephrolenellus multinodus-zone, Ovatoryctocara granulata-zone, earliest Kounamkites-zone)
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Eoagnostus

Resser and Howell, 1938
Species
  • E. roddyiResser and Howell, 1938 (Type)
  • E. acrorhachisRasetti and Theokritoff, 1967 [1]

Eoagnostus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the terminal Lower Cambrian (Toyonian), until the earliest Middle Cambrian (earliest Kounamkites-zone, part of the lower Amgaian). [1]

Contents

Distribution

Description

Almost identical to Archaeagnostus, but the frontal lobe of the central raised area of the cephalon (or glabella) is effaced, while the back of glabella is inflated. [1]

Related Research Articles

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Olenellus is an extinct genus of redlichiid trilobites, with species of average size. It lived during the Botomian and Toyonian stages (Olenellus-zone), 522 to 510 million years ago, in what is currently North-America, part of the palaeocontinent Laurentia.

<i>Acidiscus</i>

Acidiscus Rasetti, 1966, is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida Salter (1864). It lived during the Botomian stage = late Lower Cambrian Stage 4 ; the upper Botomian boundary corresponds to base of the Middle Cambrian, Miaolingian Series and Wuliuan stage.

<i>Acimetopus</i>

Acimetopus Rasetti, 1966, is a genus of Eodiscinid trilobite belonging to the family Weymouthiidae Kobayashi (1943), Order Agnostida Salter (1864). It lived during the Botomian stage. = late Lower Cambrian Stage 4 ; the upper Botomian boundary corresponds to base of the Middle Cambrian, Miaolingian Series and Wuliuan stage.

<i>Analox</i>

Analox Rasetti, 1966 is a genus of Eodiscinid trilobites belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida It lived during the Botomian stage. It can easily be distinguished from other trilobites by the two furrows that extend forwards and sidewards from the front of the glabella.

<i>Bathydiscus</i>

Bathydiscus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the Botomian stage.

<i>Bolboparia</i>

Bolboparia is an extinct genus of eodiscinid agnostid trilobites. It lived during the late Lower Cambrian in what today Canada and the United States.

<i>Buenellus</i> Species of trilobite (fossil)

Buenellus higginsi is an average size trilobite, which lived during the Lower Cambrian period, in what is now North-West Greenland. It is a prominent member of the Sirius Passet fauna. Buenellus higginsi is the only known species in the genus Buenellus.

Cirquella is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the Atdabanian stage, in the former continent Laurentia.

Egyngolia is a genus of very small sized Trilobites, that lived during the Lower Cambrian in what are today the Russia Federation, Mongolia, and South Australia.

<i>Mesonacis</i>

Mesonacis is an extinct genus of trilobite that lived during the Botomian, found in North-America, and the United Kingdom. Some of the species now regarded part of Mesonacis, have previously been assigned to Angustolenellus or Olenellus (Angustolenellus). Angustolenellus is now regarded a junior synonym of Mesonacis.

Lotagnostus is a genus of very small trilobites in the order Agnostida, which lived on the outer continental shelves worldwide, during the late Upper Cambrian. It was described by Whitehouse in 1936, and the type species is Lotagnostus trisectus, which was originally described as a species of Agnostus by Salter in 1864.

<i>Peachella</i>

Peachella is an extinct genus of trilobites, fossil marine arthropods, with species of average size. It lived during the Toyonian stage, 516 to 513 million years ago, in what is today the southwestern United States. It can easily be distinguished from other trilobites by its club-like genal spines.

Bolbolenellus is an extinct genus of trilobites, fossil marine arthropods, with five species attributed to it currently. It can be easily distinguished from all other trilobites by the combination of the absence of dorsal sutures in the head shield like all Olenellina, and a distinctly bulbous frontal lobe (L4) of the raised axial area in the head called glabella. The species lived at the end of the Lower Cambrian.

Marocconus

Marocconus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It is still debated if it lived at the very end of the Lower Cambrian or at the very beginning of the Middle Cambrian. Marocconus notabilis is the only known species in this genus.

<i>Mallagnostus</i>

Mallagnostus Howell, 1935, is a trilobite genus belonging to the family Weymouthiidae Kobayashi T. (1943), Order Agnostida Salter (1864) according to Whittington et al. 1997. It lived during the late Lower Cambrian, with remains found in USA, Canada (Newfoundland), Spain, England, Russia, Mongolia, and the early Middle Cambrian as reported from China and Russia (Yakutia).

Peronopsidae

The Peronopsidae comprise the earliest family of the Agnostina suborder. Species of this family occurred on all paleocontinents. The earliest representatives of this family first occur just before the start of the Middle Cambrian, and the last disappeared just after the start of the Upper Cambrian.

Weymouthiidae

The Weymouthiidae Kobayashi 1943 are an extinct family of eodiscinid agnostid trilobites. They lived during the late Lower Cambrian and earliest Middle Cambrian in the so-called Olenellus- and Eokochaspis-zones in the former paleocontinents of Laurentia, Avalonia, Gondwana. The Weymouthiidae are all blind and lack free cheeks.

Diplorrhina Hawle and Corda (1847) is a genus of trilobite belonging to Order Agnostida. It lived during the early Middle Cambrian in what are now the Czech Republic and the North Siberian plateau. as in members of the family Peronopsidae it lacks a preglabellar furrow. Both cephalon and pygidium lack spines. It is difficult to distinguish Diplorrhina from many other peronopsids.

<i>Orygmaspis</i> Genus of trilobites

Orygmaspis is a genus of asaphid trilobite with an inverted egg-shaped outline, a wide headshield, small eyes, long genal spines, 12 spined thorax segments and a small, short tailshield, with four pairs of spines. It lived during the Upper Cambrian in what are today Canada and the United States.

Anabaraspis is a genus of redlichiid trilobite. A. splendens occurs in the uppermost Lower Cambrian and lowest Middle Cambrian of Russia. In Anabaraspis there is a long area in front of the glabella which is not differentiated in a border and a preglabellar field. This is a unique character in the family Paradoxididae. The frontal lobe of the central raised area of the headshield is slightly pointed, rather than rounded or truncate, a character shared with Plutonides, though, in Plutonides it hangs over the short anterior border.

References

  1. 1 2 3 4 Naimark, E.B. (2012). "Hundred species of the Genus Peronopsis Hawle et Corda, 1847". Paleontological Journal. 46 (9): 945–1057. doi:10.1134/S0031030112090018. S2CID   85130465.
  2. 1 2 Whittington, H. B. et al. Part O, Treatise on Invertebrate Paleontology. Revised, Volume 1 – Trilobita – Introduction, Order Agnostida, Order Redlichiida. 1997