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Nasocephalus
Taxonomy
Nasocephalus was named by Wilson (1954) [Sepkoski's age data: Cm uMid Cm Dres-l Sepkoski's reference number: 80]. Its type is Nasocephalus nasutus.
It was assigned to Crepicephalidae by Wilson (1954); to Marjumiidae by Jell and Adrain (2002); and to Ptychopariida by Sepkoski (2002).
It was assigned to Crepicephalidae by Wilson (1954); to Marjumiidae by Jell and Adrain (2002); and to Ptychopariida by Sepkoski (2002).
Species
N. nasutus (type species)
Synonymy list
Year | Name and author |
---|---|
1954 | Nasocephalus Wilson p. 268 |
2002 | Nasocephalus Jell and Adrain p. 409 |
2002 | Nasocephalus Sepkoski |
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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.
Diagnosis
Reference | Diagnosis | |
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J.L. Wilson 1954 | Cranidium of moderate size (less than 1 cm. long), longer than wide, moderate relief to individual parts. Glabella prominent but not highly arched, rather depressed posteriorly but well defined by dorsal furrow which shallows anteriorlv,., well taoered and rounded anteriorly, with occipital ring occupying about two-thirds of axial length disregarding anterior spine; three pairs of very faint glabellar furrows, posterior two curved sharply backwards proximally; occipital ring projected backward axially, occipital spine may be present. Frontal area highly variable, brim very short but border projected anteriorly a t axis. Fixed cheeks narrow (one-fourth to one-third basal glabellar width), elevated and convex, bearing wellmarked obliquely backward trending ocular ridges and small semicircular palDebral lobes elevated above them and locatedAabout on the midwidth line through glabella; posterior limbs narrow and extended straight out, deeply furrowed.
Facial suture cuts anterior margin a t long axis on non-spinose species, proceeds straight back to eye from anterolateral corners of cranidium, indents slightly behind same and trends straight out along posterior limbs. A pygidium assigned questionably to one of the species of this genus is figured. It is convex, a little wider than long, with a large elevated axis bearing three segments and a terminal portion; pleural lobes well marked by two or three interpleural grooves which fade out posterolaterally; border lacking. |
Measurements
No measurements are available
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Source: f = family, c = class | |||||
References: Aberhan et al. 2004, Whittington et al. 1997 |
Age range: base of the Marjumian to the top of the Dresbachian or 504.50000 to 485.40000 Ma
Collections (7 total)
Time interval | Ma | Country or state | Original ID and collection number |
---|---|---|---|
Marjumian | USA (Texas) | N. flabellatus (228 78733) N. nasutus (78734 78735) | |
Dresbachian | Canada (Yukon) | N. flabellatus (55216 55217 55220) |