| Psychopyge | |
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| Psychopyge elegans | |
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| Genus: | Psychopyge Termier & Termier, 1950 [1] |
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Psychopyge is a genus of trilobite, that lived during the upper Emsian (or Lower Devonian) and has been found in Germany (P. psyche) and Morocco. It is characterized by the swordlike extension from the front of the head.
Like all sighted Phacopina, Psychopyge has schizochroal eyes, the frontal lobe of the central raised area of the headshield (or cephalon), called glabella is expanded forward, lacks a rostral plate (the midfrontal part of the “seam” visible from the ventral side, defined by sutures), and the articulate middle part of the exoskeleton (or thorax) has 11 segments. Like all Asteropyginae, Psychopyge has (in this case 5 pairs) prominent spines (or lappets) extending from the segments of the tailshield (or pygidium) in the area outside the axis (or pleural region). The frontal lobe of the glabella is rounded, the border carries a long flat sword-shaped forward pointing extension. The furrows dividing the frontal lobe of the glabella is curved inward and backward. The eyes have 9–10 lenses per vertical row (or dorsoventral file). The eye does not touch the border furrow at the back of the cephalon, and there is no platform below the eye. The large spines at the back corners of the cephalon (genal spines) are longer than glabella. There is a long vertical spine on the part of the glabella that corresponds with the border (called occipital ring), gradually curving backward. There are no spines between the genal spines and the glabella (or metafixigenal spines). The pygidium has 19-21 axial rings, each with a spine on its midpoint. The part of the pygidium outside the axis (or pleura) has 5–6 segments that get longer further to the back, with rounded pleural bands, clearly incised furrows between the bands and vertical spines near where each posterior band converts into a lappet. There are 5 pairs of lappets that grow only from the posterior pleural bands, and are longer than the corresponding pleural bands. [1]
Psychopyge is most related to Quadrops , Saharops , and Walliserops . These genera share that the posterior pleural bands of the pygidium are much wider as the anterior band, the pleural segments are twice as wide near the base of the spine as at the axis and pygidial spines are connected only with the posterior pleural bands. Further in all these genera the pygidial spines are longer than the pleural segment, are round in section and are as wide as the posterior pleural bands. These genera also have inward and backward curved glabellar furrows and lateral borders developed on the genal spines, which are square in section. [1]
Dalmanites is a genus of trilobite in the order Phacopida. They lived from the Late Ordovician to Middle Devonian.
Paradoxides is a genus of large to very large trilobite found throughout the world during the Middle Cambrian period. One record-breaking specimen of Paradoxides davidis, described by John William Salter in 1863, is 37 cm (15 in). The cephalon was semicircular with free cheeks ending in long, narrow, recurved spines. Eyes were crescent shaped providing an almost 360° view, but only in the horizontal plane. Its elongate thorax was composed of 19-21 segments and adorned with longish, recurved pleural spines. Its pygidium was comparatively small. Paradoxides is a characteristic Middle-Cambrian trilobite of the 'Atlantic' (Avalonian) fauna. Avalonian rocks were deposited near a small continent called Avalonia in the Paleozoic Iapetus Ocean. Avalonian beds are now in a narrow strip along the East Coast of North America, and in Europe.
Huntoniatonia is genus of trilobites, an extinct group of marine arthropods of average to large size.
Agnostus, is a genus of agnostid trilobite belonging to the Family Agnostidae, that lived during the late Middle Cambrian – early Upper Cambrian. It is the type genus of the family Agnostidae and is subdivided into two subgenera, Agnostus and Homagnostus.
Dikelocephalus is a genus of very large trilobites of up to 50 cm (20 in) long, that lived during the last 3 million years of the Cambrian (Sunwaptan). Their fossils are commonly found as disarticulated sclerites, in the upper Mississippi Valley and in Canada (Alberta). The exoskeleton is rounded anteriorly, with the thorax and sides of the tailshield slightly tapering to about ⅔× of the width across the base of the spines at the back of the headshield. At the side corners of the pygidium there may be triangular or hooked spines, pointing backwards, while between the spines the posterior margin is at a 30-75° angle with the lateral margin, gently convex or nearly straight. If pygidial spines are lacking, the margin is gradually rounded. The thorax has 12 segments.
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.
Dicerodiscus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the early part of the Botomian stage, in China. Four species have been assigned to it. Dicerodiscus is unique for an eodiscoid in having conspicuous and curved spines that are attached anteriorly, and at their base are directed outward perpendicular to the midline, before gradually bending further backwards.
Meteoraspis is an extinct genus of ptychopariid trilobites of the family Tricrepicephalidae. The various species lived from 501 to 490 million years ago during the Dresbachian faunal stage of the late Cambrian Period. Fossils of Meteoraspis are characteristic of Late Cambrian strata in North America, though they are found in Late Cambrian strata elsewhere in the world, such as M. nevensis from Victoria Land, Antarctica.
Acadagnostus is a genus of trilobite from the Middle Cambrian, with 7 species currently recognized. The type species A. acadicus has the widest distribution known from any peronopsid and has been found in North America, Greenland, England, Western Europe, Eastern Europe, Central Asia, the Altai Mountains, the Siberian shield, China, and Australia.
Erbenochile is a genus of spinose phacopid trilobite, of the family Acastidae, found in Lower to Middle Devonian age rocks from Algeria and Morocco. Originally described from an isolated pygidium, the first complete articulated specimen of E. erbeni revealed the presence of extraordinarily tall eyes:
"Straight-sided towers of lenses... with [up to] 18 lenses in a vertical file"
Morocconites malladoides is an average size trilobite, which lived during the Devonian period, in what is now southern Morocco. This species is assumed to be a close relative of Acastoides. The most conspicuous feature is the very long upcurved frontal medial spine, a bit like an avocet bill. It is the only known species in this genus.
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.
Biceratops is an extinct genus of olenelloid redlichiid trilobites, of average size, with the largest specimen 8 centimetres or 3.1 inches long, not including the huge pleural spines of the 3rd segment of the thorax. It lived during the Toyonian stage, in what is today the South-Western United States. Biceratops can easily be distinguished from other trilobites by the absence of genal spines, in combination with effaced features of the raised axial area of the head shield, that is bordering the two horn-like projections that carry the eyes. Biceratops nevadensis is the only known species in this genus.
Ptychoparia is a genus of ptychopariid trilobites, and is the type genus of the family Ptychopariidae, and the order Ptychopariida.
Odontochile is a genus of trilobites in the order Phacopida, family Dalmanitidae.
Geragnostus is a genus of very small agnostid trilobites whose fossils are found Ordovician-aged marine strata from Eurasia, North America and Argentina.
Coltraneia is a genus of trilobite, that lived during the upper Emsian and lower Eifelian, and has been found in Algeria, France, Germany, Morocco and Spain.
Minicryphaeus is a genus of trilobite, that lived during the Pragian in what is today Morocco (Anti-Atlas).
Tricrepicephalus is an extinct genus of ptychopariid trilobites of the family Tricrepicephalidae with species of average size. Its species lived from 501 to 490 million years ago during the Dresbachian faunal stage of the late Cambrian Period. Fossils of Tricrepicephalus are widespread in Late Cambrian deposits in North America, but is also known from one location in South-America. Tricrepicephalus has an inverted egg-shaped exoskeleton, with three characteristic pits in the fold that parallels the margin of the headshield just in front of the central raised area. The articulating middle part of the body has 12 segments and the tailshield carries two long, tubular, curved pygidial spines that are reminiscent of earwig's pincers that rise backwards from the plain of the body at approximately 30°.
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.
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