PBDB Taxon

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Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Achatella

Trilobita - Phacopida - Pterygometopidae

Taxonomy

Achatella was named by Delo (1935).

It was assigned to Pterygometopidae by Jell and Adrain (2002); to Phacopida by Sepkoski (2002); and to Pterygometopinae by Jaanusson and Ramsköld (1993), Swisher et al. (2016).

Species

A. (Achatella), A. (Vironiaspis) kegelensis, A. achates (syn. Pterygometopus billingsi), A. katharina, A. kuckersianus, A. schmidti, A. truncatocaudata

Species lacking formal opinion data

A. billingsi

Synonyms

Achatella (Vironiaspis) was named by Jaanusson and Ramsköld (1993).

It was reranked as Vironiaspis by Roomusoks (2004); it was synonymized subjectively with Achatella by Swisher et al. (2016).

It was assigned to Achatella by Jaanusson and Ramsköld (1993); and to Trilobita by Roomusoks (2004).

Synonymy list

Year	Name and author
1935	Achatella Delo
1993	Achatella Jaanusson and Ramsköld
1993	Achatella (Vironiaspis) Jaanusson and Ramsköld
2002	Achatella Jell and Adrain p. 337
2002	Achatella Sepkoski
2004	Vironiaspis Roomusoks
2016	Achatella Swisher et al. p. 62

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Protostomia
—	Ecdysozoa	Aguinaldo et al. 1997
—	Panarthropoda
phylum	Arthropoda	Latreille 1829
subphylum	Artiopoda	(Hou and Bergstrom)

Rank	Name	Author
class	Trilobita	Walch 1771
order	Phacopida	Salter 1864
suborder	Phacopina	Struve 1959
superfamily	Phacopoidea	Hupe 1953
family	Pterygometopidae	Reed 1905
subfamily	Pterygometopinae	Reed 1905
genus	Achatella	Delo 1935

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. †Achatella Delo 1935

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Subg. †Achatella (Achatella) Delo 1935

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†Achatella (Achatella) bailyi Salter 1864

†Achatella (Achatella) consobrina Tripp 1954

†Achatella (Achatella) nieszkowskii Schmidt 1881

†Achatella achates Billings 1860

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Invalid names: Pterygometopus billingsi Wilson 1947 [synonym]

†Achatella katharina Bradley 1930

†Achatella kuckersianus Schmidt 1881

†Achatella schmidti Warburg 1925

†Achatella truncatocaudata Portlock 1843

Invalid names: Vironiaspis Jaanusson and Ramsköld 1993 [synonym]

Diagnosis

Reference	Diagnosis
R. E. Swisher et al. 2016	Cephalon relatively flat with a weak anterior arch [1(1)]. L3 lobe subtriangular with conspicuous adaxial taper [7(1)], and longer (exsag.) than L1 and L2 [8(1)]. Posterior branch of facial suture nearly straight [16(1)]. Pygidium elongate, subtriangular in outline.