We have included some recent changes in taxonomy here on this page. Not all changes are necessarily agreed on by all, they are simply the most recent changes (to date) that we have been able to locate. Many of these assignments can be confirmed in the Jell & Adrain (2003) Trilobite genera paper. The taxonomic assignments on many of the lists are out of date and it's a huge job to keep up with all the most recent name changes. If you know of any recent changes and would like to point them out, please email us. We will do our best to include them (at least on this page). Please include the reference with any submissions.


Old taxonomic designation in [square brackets]

[Anomalocephalus] =  Ehmaniella

        (Anomalocephalus is a j.s.s. of Ehmaniella, fide HOWELL in
        MOORE, 1959) (see Jell & Adrain 2003)

[Bynumiella] = Clelandia

        (Bynumiella is a j.s.s. of  Clelandia, fide PALMER, 1965) (see Jell & Adrain 2003)
[Clappaspis] = Ehmaniella

        (Clappaspis is a j.s.s. of Ehmaniella) (see Jell & Adrain 2003)

[Coelaspis] = Elrathiella

        (Coelaspis is a j.s.s. of Elrathiella) (see Jell & Adrain 2003)
[Glossocoryphus] = Elrathiella

        (Glossocoryphus is a j.s.s. of Elrathiella) (see Jell & Adrain 2003)

[Goniotelus] = Acidiphorus

        (Goniotelus is a j.s.s. of Acidiphorus, fide BRETT & WESTROP, 1996) (see Jell & Adrain 2003)

[Hypothetica] = Entomaspis

        (Hypothetica is a j.s.s. of Entomaspis, fide ADRAIN 2003) (see Jell & Adrain 2003)

[Kirkella] = Ptyocephalus

        (Kirkella is a j.s.s. of Ptyocephalus, fide WHITTINGTON, 1948) (see Jell & Adrain 2003)
[Mcnairia] = Parehmania

        (Mcnairia is a j.s.s. of Parehmania) (see Jell & Adrain 2003)

[Platycolpus] RAYMOND, 1913a [preocc. replaced by Rasettia] (see Jell & Adrain 2003)
[Rowia] = Parehmania

        (Rowia is a j.s.s. of Parehmania) (see Jell & Adrain 2003)

[Strotocephalus] = Amecephalus

        (Strotocephalus is a j.s.s. of Amecephalus) (see Jell & Adrain 2003)

[Syspacephalus] = Ptychoparella

       (Syspacephalus is a j.s.s. of Ptychoparella) (see Jell & Adrain 2003)
[Thomsonaspis] = Parehmania

        (Thomsonaspis is a j.s.s. of Parehmania) (see Jell & Adrain 2003)




Genera not published (from unpubl. dissertations, or awaiting publication):


Selenocoryphe is an unpublished genus in Beebe's thesis.

"Gerospina" (Shanan Peters dissertation, 2003, unpubl.)

"Nephalicephalus" (Shanan Peters dissertation, 2003, unpubl.)


Labiostria is considered a junior synonym of Aphelaspis, fide PALMER, 1965 (see Jell & Adrain 2003 and discussion below).


        According to the Jell & Adrain 2003 Trilobite Genera paper, Labiostria is now a junior synonym of Aphelaspis, fide PALMER, 1965. Therefore Labiostria westropi should be called Aphelaspis westropi. This has been debated post-Palmer, 1965 by both Pratt, 1992 and Chatterton & Ludvigsen, 1998. According to Chatterton & Ludvigsen, 1998, the genus Labiostria is retained for L. westropi, as it more similar to the type species of Labiostria, than it is to the type for Aphelaspis.

        We agree with Chatterton and Ludvigsen's designation and retain the name Labiostria westropi, until further work on Aphelaspidinids is done.


“Remarks.—In the Treatise (Moore, 1959), Labiostria was placed by Lochman-Balk in the Pterocephaliidae. However, as shown in this work and by Chatterton et al. (1994b, fig. 6.6), Pterocephalia has a median suture, and a rostellum in at least some stages. At least two specimens of Labiostria (Figure 18.8, 18.9) show what appear to be posteriorly convergent connective sutures, so that there may have been a narrow trapezoidal to triangular rostral plate present. Although a significant fraction of the molts appear to have the cheeks still fused to one another (Figures 18.3, 19.4, 19.6), suggesting that these sutures were not always functional, at least as many specimens were found where the cheeks acted independently during molting (Figure 19.2?, 19.7), implying that this species often had a functional suture.

        The occasional presence of fine granules or pustules in the anterior border furrow (Figure 18.10), and presence of functional connective sutures, a rostral plate and a doublure that does not extend beyond the border furrow would appear to support as­signment of Labiostria to the Idahoiidae. Westrop (1986), how­ever, considered members of that family to have a median suture, showing two free cheeks of Wilbernia explanata (Whitfield) with what could well be a median suture. In other features, our species fits Westrop's (1986) diagnosis for this family. The pustules in the anterior border furrow occur in quite a wide range (at family level) of trilobites (e.g., Proricephalus in Westrop, 1986, pi. 10, figs. 8 and 9; Orygmaspis in Westrop, 1986, pi. 17, fig. 15; Cedaria in Palmer, 1962, pi. 3, fig. 14). It is difficult to judge the phylogenetic significance of this feature at this time. Pratt (1992) included Labiostria in the pterocephalid subfamily Aphelaspidinae. He disagreed with Palmer's (1962) decision to place Labiostria in synonymy with Aphelaspis on the grounds that the former has a median suture (Pratt, 1992, pi. 14, fig. 20; Palmer 1954, pi. 86, fig. 7) and the latter a rostral plate. However, both of the cheeks that Pratt (1992, p. 57) referred to are disarticulated and could have either a median suture or paired connective sutures and a rostral plate, although the connective sutures are not consistent with the almost triangular rostral plate found in L. westropi. Superimposing a tracing of the cheek of Labiostria platifrons Palmer on the cranidium of that species would suggest, if the cheek is complete, that that species had a rostral plate (the tip of the doublure of the free cheek comes nowhere near the midline). This is equally true for the specimens of Labiostria conveximarginata Palmer illustrated by Pratt (1992, pi. 14). Thus, we argue that Labiostria has a rostral plate, but the connective sutures were not always functional. This re­moves the distinction made by Pratt between Aphelaspis and Labiostria. This leaves the main distinction between Aphelaspis and Labiostria being the depth of the border and pleural furrows and the number of segments in the pygidium. These features may not be sufficient for preventing synonymy of these genera, but since our species is more similar to Labiostria conveximar­ginata than it is to Aphelaspis walcotti Resser, 1938, the type species of Aphelaspis, we have included our species in Labios­tria for the present. We have removed the Aphelaspidinae from the Pterocephaliidae since its members lack a median suture, and often appear to have a triangular to trapezoidal rostral plate.” (quote from Chatterton and Ludvigsen, 1998)




Wenkchemnia is considered a junior synonym of Bathyuriscus, fide ROBISON, 1976 (see Jell & Adrain 2003 and discussion below).

Wenkchemnia is apparently a junior synonym of Bathyuriscus, fide ROBISON, 1976 according to Jell and Adrain, 2003. Fred Sundberg and others strongly believe that Wenkchemnia Rasetti, 1951 is a valid genus and that Dick Robison shouldn't have placed it in synonomy with Bathyuriscus Meek, 1873.  Both Sundberg & Robison stick to their positions, so the issue is unresolved. For our list, we will go with the genus that the author of the species uses. All species of Wenkchemnia should perhaps be called Wenkchemnia (?=Bathyuriscus) spp.




Most recent names for olenellids (see Lieberman, 1999):


[Olenellus arcuatus] = Arcuolenellus arcuatus (see Palmer & Repina  1993)
[Olenellus euryparia] = Bolbolenellus euryparia (see Palmer & Repina  1993)
[Olenellus multinodus] = Nephrolenellus multinodus (see Palmer & Repina  1993)
[Fremontia] = Olenellus (Mesonacis) (see Palmer & Repina  1997)


Olenellus (Mesolenellus) hyperborea (see Palmer & Repina  1993)
Olenellus (Mesonacis) cylindricus (see Lieberman 1999)
Olenellus (Mesonacis) fremonti (in Treatise 1997)
Olenellus (Olenellus) gilberti (see Palmer 1998)
Olenellus (Olenellus) fowleri (see Palmer 1998)
Olenellus (Paedeumias) chiefensis (see Palmer 1998)
Olenellus (Paedeumias) clarki (see Resser 1928)
Olenellus (Paedeumias) granulatus (see Lieberman, 1999)
Olenellus (Paedeumias) nevadensis (see Resser 1928)
Olenellus (Paedeumias) terminatus (see Palmer 1998)

"Olenellus" brachyomma is in the Carrara Formation, Gold Ace Ls. Mbr.

No paper assigning Olenellus howelli, puertoblancoensis to a specific subgenus






Beebe 1990. Trilobite faunas and depositional environments of the Weeks Formation (Cambrian), Utah. University of Kansas PhD thesis, 117 pp. Not only the most extensive and most important paper on the geology and paleontology of the Weeks Fm., it is the essentially the only paper. Unfortunately, Beebe's work was left unpublished due to his untimely death, and therefore most of the new genera and species described are not entirely valid (until published).


Chatterton, B. D. E. and Ludvigsen, R. (1998)  Upper Steptoean (Upper Cambrian) trilobites from the McKay Group of southeastern British Columbia, Canada. The Paleontological Society, Memoir 49, Journal of Paleontology, Vol. 72, March, 1998, Supplement to No. 2, 43 pp.


Jell, P. A. & Adrain, J. M. (2003) Available generic names for trilobites. Memoirs of the Queensland Museum 48 (2): 331-553. Brisbane

Lieberman, B. S. (2002) Phylogenetic analysis of some basal early Cambrian trilobites, the biogeographic origins of the Eutrilobita, and the timing of the Cambrian radiation. Journal of Paleontology, Vol. 76, No. 4, pp. 692-708.

Lieberman, Bruce S.; 1999. Systematic Revision of the Olenelloidea (Trilobita, Cambrian). Bulletin 45, Peabody Museum of Natural History, Yale University


Palmer, Allison R. & Repina, Lada N.; 1993. Through a Glass Darkly: Taxonomy, Phylogeny, and Biostratigraphy of the Olenellina. Univ. Kansas Paleontological Contributions, New Series No.3

Palmer, Allison R.; 1998. Terminal Early Cambrian Extinction of the Olenellina: Documentation from the Pioche Formation, Nevada. J.Paleontology 72(4):650-672


Resser, Charles E.; 1928. Cambrian Fossils from the Mohave Desert. Smith.Misc.Coll. Vol.81,No.2



*researched by James Cook, Kevin Brett


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