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Amecephalus
Taxonomy
Amecephalus was named by Walcott (1924) [Sepkoski's age data: Cm Tojo-u Cm mMid-u Sepkoski's reference number: 81]. It is not extant. Its type is Ptychoparia piochensis.
It was synonymized subjectively with Alokistocare by Palmer (1954), Palmer and Halley (1979).
It was assigned to Ptychopariidae by Matthew (1887); to Olenidae by Mason (1935); to Ptychopariacea by Sundberg and McCollum (2000); to Ptychopariida by Sepkoski (2002); and to Alokistocaridae by Jell and Adrain (2002), Sundberg (2018).
It was synonymized subjectively with Alokistocare by Palmer (1954), Palmer and Halley (1979).
It was assigned to Ptychopariidae by Matthew (1887); to Olenidae by Mason (1935); to Ptychopariacea by Sundberg and McCollum (2000); to Ptychopariida by Sepkoski (2002); and to Alokistocaridae by Jell and Adrain (2002), Sundberg (2018).
Synonyms
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Synonymy list
| Year | Name and author |
|---|---|
| 1887 | Amecephalus Matthew |
| 1924 | Amecephalus Walcott |
| 1935 | Amecephalus Mason p. 105 |
| 1935 | Strotocephalus Resser p. 45 |
| 2000 | Amecephalus Sundberg and McCollum p. 607 |
| 2002 | Amecephalus Jell and Adrain p. 465 |
| 2002 | Amecephalus Sepkoski |
| 2018 | Amecephalus Sundberg p. 39 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
G. †Amecephalus Walcott 1924
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†Amecephalus agnesensis Walcott 1912
†Amecephalus arrojosensis Lochman 1952
†Amecephalus cleora Walcott 1917
†Amecephalus idahoense Resser 1939
†Amecephalus jamisoni Robison and Babcock 2011
†Amecephalus laticaudum Resser 1939
†Amecephalus normale Resser 1938
†Amecephalus strangulatus Mason 1935
Invalid names: Strotocephalus Resser 1935 [synonym]
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| F. A. Sundberg and L. B. McCollum 2000 | Cranidia with an anterior border slight- ly tapered distally, no medial inbend, poorly defined anterior border furrow. Glabella moderately elongated, strongly tapered from S0 to S2 then slightly tapered, S1 and S2 bifurcated; axial furrows deepest posteriorly. S0 moderately shallow. Posterior area of fixigena strap-like with sharp termination, border widens distally; border furrow extends to suture. Anterior branches of facial sutures slightly to strongly divergent to midlength (exsag.) of anterior border; posterior branches strongly divergent to pos- terior border furrow, then nearly parallel. Librigena spine flat- tened, broad-based. Pygidium suboval, micropygous; axis with one or two axial rings; poorly developed anterior pleural band; anterolateral corners rounded, opposite anterior half of the axis; posterior margin with median notch arched in posterior view; doublure absent behind axis. |
Measurements
No measurements are available
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| Source: g = genus, f = family, c = class | |||||
| References: Aberhan et al. 2004, Hendy 2009 | |||||
Collections (73 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Cambrian | Argentina (San Juan) | A. arrojosensis (200106) | |
| Dyeran | Canada (Yukon Territory) | A. sp. (156238) | |
| Toyonian | Russian Federation | Alokistocare laticaudum (225260) | |
| Delamaran | USA (Utah) | Alokistocare idahoense (75635 75636 75639) A. laticudum, Alokistocare normale (10533) | |
| Delamaran | USA (Idaho) | Alokistocare idahoense, Alokistocare laticaudum (76096) | |
| Delamaran | USA (California) | A. arrojosensis (69497 69498 69499 69500 69504 69506 69510 69512) A. piochensis, A. strangulatus (191414) A. sp. (226840) | |
| Delamaran | USA (Nevada) | A. arrojosensis (10587 69280 69401 69403 69404 69432 69437 69447 69456) A. laticaudum (77203 77204 77205) | |
| Delamaran | Canada (British Columbia) | A. agnesensis (225262) A. cleora (225263 225264) A. sp. (197) Olenopsis agnesensis (50544) Olenopsis cleora (225278) | |
| Delamaran - Topazan | USA (Utah) | Ptychoparia piochensis (227007) | |
| Delamaran - Menevian | Mexico | A. arrojosensis (10687) | |
| Solvan | USA (Nevada) | A. arrojosensis (9218 9234 9241 9250 9251 9261) A. sp. A Sundberg & McCollum 2000 (9249) | |
| Solvan | Canada (British Columbia) | Alokistocare cleora (56702 56703 56704 56716 56718 56720 56721) | |
| Wuliuan | Argentina (Mendoza) | A. laticaudum (220418 222585) A. normale (220535) A. sp., A. laticaudum, A. normale (223357) | |
| Middle Cambrian | USA (Idaho) | Alokistocare normale (127486) | |
| Middle Cambrian | Canada (Northwest Territories) | A. sp. (88786 88787 88788 88789) | |
| Middle Cambrian | Canada (British Columbia) | Alokistocare cleora (188658) | |
| St Davids | USA (Nevada) | A. arrojosensis (50093 50109 50114 50295 50296 50329 50331 50332 50339) A. sp. (50337) | |
| Merioneth | Canada (British Columbia) | A. sp. (199) |