Rickard Hill Trilobite, Kalkberg Formation

[Bennett-s]

During my visit to the Rickard Hill Road site I lucked out and found this trilobite in a slab. I think it is enrolled but I’m too scared to prepare it because I will probably destroy it by accident and I only found one trilobite.

 

Anyone know the species?

[FossilDAWG]

It's a phacopid for sure.  I think the Kalkberg is a little old for Eldredgeops so it might be a Phacops such as P. cristata, but I'm not absolutely certain of that.  @piranha, @Kane, or @Jeffrey P may know for certain.  Complete trilobites from that site are quite rare, so this specimen might be worth investing in a professional prep.

 

Don

[Kane]

Burtonops, methinks. No Phacops in ENA.

[Fossildude19]

Burtonops cristatus looks correct.

 

LINK

[piranha]

The status of Burtonops is awaiting an upcoming revision:

 

 

"We make note of taxa from the Lower to Middle Devonian of ENA (see above for remarks on the Givetian taxa), and particularly of species assigned to Paciphacops Maksimova, 1972, Viaphacops Maksimova, 1972 and Burtonops. Struve (1990) erected the latter genus for phacopids from ENA with a rather brief diagnosis pertaining only to the divergent genal spines. McKellar & Chatterton (2009) deemed Burtonops a problematic taxon. According to those workers, the type species of Burtonops, Phacops cristatus Hall, 1861, had been synonymised with Phacops pipa Hall & Clarke, 1888 (type species of Viaphacops) by Eldredge (1973). Actually, Eldredge (1973) only stated that he could not distinguish Phacops bombifrons Hall, 1861 from P. pipa and that the former should have precedence. McKellar & Chatterton (2009) confused things further by attempting to suppress Burtonops, while considering it to be a junior objective synonym of Viaphacops. Based on their cladistic analysis, they argued that the validity of Viaphacops is called into question and that it should be treated as a subgenus of Paciphacops. However, based on their interpretation of the proposed synonymy by Eldredge (1973), McKellar & Chatterton (2009) used Phacops cristatus (the type species of Burtonops) to code Viaphacops for analysis. The type species of Viaphacops, V. pipa, is in need of revision. Stumm (1954: pl. 4, figs 1-6, 9, 11, 1964: pl. 3, figs 1-15) and Eldredge (1973: fig. 32A-E) figured specimens from various stratigraphic units and locations which are too dissimilar from one another to possibly belong to a single species. The synonymy of V. pipa and P. bombifrons that was claimed by Eldredge (1973) has not been adopted by other workers (e.g., Jell & Adrain 2003) whereas bombifrons has been treated as a distinct species of Viaphacops (e.g., Whiteley et al. 2002, Hansen 2009). Nevertheless, V. pipa, V.? bombifrons and B. cristatus have not been revisited recently and they were also not included in the cladistic analyses of Ramsköld & Werdelin (1991) or Ebach (2002). Although we agree with McKellar & Chatterton (2009) that Burtonops as a taxon of independent generic rank was poorly outlined by Struve (1990), its fate must await revision of its type species and the Paciphacops-Viaphacops group."

 

Van Viersen, A.P., Koppka, J. 2021
Type and other Species of Phacopidae (Trilobita) from the Devonian of the Ardenno-Rhenish Mountains.
Mainzer Geowissenschaftliche Mitteilungen, 49:25-66  PDF LINK

[Bennett-s]

1 hour ago, FossilDAWG said:

Complete trilobites from that site are quite rare, so this specimen might be worth investing in a professional prep.

It may be complete. I will take some more photos of it from different angles and provide a scale in a subsequent reply later. Maybe someone can give me a good idea of if it is prep-worthy at that point.  I appreciate the replies about the identification as well. 

[Misha]

Wow! Great find.

[trilobites_are_awesome]

Amazing trilobite!

Definitely worth the professional prep!

[Newbie_1971]

I could totally be wrong. But it looks to be as good as you are going to get it. But a good prepper will be able to tell you if it is or not. I  personally think it looks cool as is! Congrats on your find!

[trilobites_are_awesome]

2 hours ago, Newbie_1971 said:

I could totally be wrong. But it looks to be as good as you are going to get it. But a good prepper will be able to tell you if it is or not. I  personally think it looks cool as is! Congrats on your find!

No, I think some skilled prep would do this piece wonders!

I'm pretty confident that the pygidium is present.

[Fossildude19]

Looks like a complete, enrolled trilobite to me, as well.

[Bennett-s]

Here are some additional images I took. I’m thinking of reaching out for a prep quote. Measurements are in centimeters.

 

Is Viaphacops cristatus the same as Burtonops cristatus? My New York Devonian guide Wilson (2014) records V. cristatus in the Onondaga Formation, Middle Devonian, but it doesn’t list Helderberg Formation. What it has for the latter is Paciphacops logani, Synphoroides pleuroptyx, and Anchiopella anchiops. 

Edited June 6 by Bennett-s
Edit to add

[piranha]

2 hours ago, Bennett-s said:

Is Viaphacops cristatus the same as Burtonops cristatus?

 

 

Yes. Although it has not been formally addressed yet, the consensus among trilobite workers indicates that we can likely expect that Burtonops will be suppressed in favor of Viaphacops.