Agnostus pisiformis, from here.

Belongs within: Agnostina.

The Agnostinae are a group of agnostids known from the Middle Cambrian to Early Ordovician, characterised by a simple, axiolobate pygidium (Shergold et al. 1990).

Characters (from Shergold et al. 1990): En grande tenue to largely effaced, nondeliquiate to deliquiate border furrows; acrolobes usually unconstricted; preglabellar median furrow absent to well developed. Glabella with large ogival, semiovate, subpentagonal, subquadrate or trapeziform anterior lobe; F3 straight to concave forward; F2 absent to well developed; glabellar culmination variably rounded, subquadrate or obtusely angular; glabellar node from midway between Fl and F2 to level with F2; basal lobes variable in size, usually simple, occasionally incorporating lateral portions of M2 lobe. Pygidium bispinose or nonspinose, with agnostoid or basic articulating device; axis usually long, not reaching border furrow, with a slight constriction across M2; Fl variably impressed, rarely effaced; Ml usually trilobate; F2 variably impressed, rarely effaced; posterior lobe usually long, semiovate, ogival, semicircular or bulbous, with or without terminal node.

Agnostinae [Rudagnostidae]
|--Eurudagnostus Lermontova 1951SS84
| `--*E. grandisSS84
|--Innitagnostus Öpik 1967S80
| |--*I. innitens Öpik 1967S80
| |--I. inexpectansS80
| `--I. medius Shergold 1980S80
|--Homagnostus Howell 1935SS84
| |--*H. obesus (Belt 1867) [=Agnostus pisiformis var. obesus]SS84
| |--H. comptus Palmer 1962S80
| |--H. holiformisCT83
| `--H. tumidosusSS84
|--Acmarhachis Resser 1938 [incl. Cyclagnostus Lermontova 1940]S80
| |--*A. typicalis Resser 1938S80
| |--A. acuta (Kobayashi 1938) [=Homagnostus acutus, A. acutus (l. c.)]S80
| |--‘Cyclagnostus’ elegans Lermontova 1940S80
| |--A. hybrida Shergold 1980S80
| `--A. quasivespa (Öpik 1967)HLC03, S80 [=Cyclagnostus quasivespaS80]
| | i. s.: L. asiaticusCT83
| | L. hedini [=Agnostus hedini]CT83
| | L. punctatusCT83
| | L. trisectusS80
| `--L. (Trilobagnostus)S80
| |--L. (T.) ergodes Shergold 1972S80
| `--L. (T.) irretitus Shergold 1975S80
|--Agnostus Brongniart 1821W77
| |--A. captiosus Lazarenko 1966SS84
| |--A. czekanowskiiT10
| |--A. gibbusA38
| |--A. inconstansCT83
| |--A. integerW77
| |--A. interstrictus White 1874W77
| `--A. pisiformisA38
`--Micragnostus Howell 1935 [incl. Rudagnostus Lermontova 1951]SS84
|--*M. calvus (Lake 1906) [=Agnostus calvus]SS84
|--M. bavaricus (Barrande 1868)SS84
|--M. brevispinus (Lermontova 1951) [=Eurudagnostus brevispinus]SS84
|--M. chiushuensis [=Geragnostus (Micragnostus) chiushuensis]CT83
|--M. coreanicus Kobayashi 1960SS84
|--M. curvatus (Robison & Pantoja-Alor 1968)SS84
|--M. haudei Shergold & Sdzuy 1984SS84
|--M. intermedius (Palmer 1968)SS84
|--M. kazachstanicus (Ergaliev 1980) [=Eurudagnostus kazachstanicus]SS84
|--M. minor (Ergaliev 1980) [=Eurudagnostus minor]SS84
|--M. orientalisCT83
|--M. ovaliformis (Ergaliev 1980) [=Eurudagnostus ovaliformis]SS84
|--M. serus Fortey 1980SS84
`--M. splendens (Holub 1912)SS84

*Type species of generic name indicated


[A38] Alcock, F. J. 1938. Geology of Saint John region, New Brunswick. Geological Survey of Canada Memoir 216: 1–65.

[CT83] Chen J.-Y. & C. Teichert. 1983. Cambrian Cephalopoda of China. Palaeontographica Abteilung A: Paläozoologie—Stratigraphie 181 (1–3): 1–102.

[HLC03] Hong, P. S., J. G. Lee & D. K. Choi. 2003. Trilobites from the Lejopyge armata zone (upper Middle Cambrian) of the Machari Formation, Yongwol Group, Korea. Journal of Paleontology 77 (5): 895–907.

[S80] Shergold, J. H. 1980. Late Cambrian trilobites from the Chatsworth Limestone, western Queensland. Bureau of Mineral Resources, Geology and GeophysicsBulletin 186: 1–111.

Shergold, J. H., J. R. Laurie & Sun X. 1990. Classification and review of the trilobite order Agnostida Salter, 1864: an Australian perspective. Bureau of Mineral Resources, Geology and Geophysics—Report 296.

[SS84] Shergold, J. H., & K. Sdzuy. 1984. Cambrian and early Tremadocian trilobites from Sultan Dağ, central Turkey. Senckenbergiana Lethaea 65 (1–3): 51–135.

[T10] Taylor, T. G. 1910. The Archaeocyathinae from the Cambrian of South Australia with an account of the morphology and affinities of the whole class. Memoirs of the Royal Society of South Australia 2 (2): 55–188.

[W77] White, C. A. 1877. Report upon the invertebrate fossils collected in portions of Nevada, Utah, Colorado, New Mexico, and Arizona, by parties of the expeditions of 1871, 1872, 1873, and 1874. U.S. Geographical Surveys West of the One Hundredth Meridian 4 (1): 1–219, pls 1–21.

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