Unidentified Fern

[Bguild]

Hi All,

 

I'm having a hard time nailing down an exact ID for this large fern imprint I found earlier this month. This imprint is from the Pennsylvanian time period and was found in the Rhode Island Formation. below I've included a list of the possible suspects/known flora from the Rhode Island Formation.

 

It doesn't help that fossils from the Rhode Island Formation are often distorted. This distortion can be seen in the close up image of the pinnules below. The red arrows are pointing to pinnules I believe are the way they should look versus distorted.

 

Anyone have any ideas as to an ID??

 

Thanks as always!

 

 

[fossilcrazy]

An important part of identifying ferns like this, is the vein patterns in the leaflets. I can't see that kind of detail in your pictures. You have a nice fern specimen, whatever it is. 

[Bguild]

47 minutes ago, fossilcrazy said:

An important part of identifying ferns like this, is the vein patterns in the leaflets. I can't see that kind of detail in your pictures. You have a nice fern specimen, whatever it is. 

 

Yep! I've only found a couple specimens from Rhode Island with the smaller veins preserved. The lack of vein preservation always throws me for a loop.

[Herb]

try the sites of the Indiana and Illinois Geologic Surveys, both have good plant ID prints.

[Wrangellian]

Are there no publications on the Rhode Island Fm plants yet, however difficult it/they might be to find?

[Bguild]

15 hours ago, Wrangellian said:

Are there no publications on the Rhode Island Fm plants yet, however difficult it/they might be to find?

 

Here's the only publication I know of. 

 

Rhode Island Formation Flora list (1).pdf

 

 

 

[doushantuo]

(Wagner/Lyons,1997,RPP)

"This flora has been attributed to Westphalian C (=Bolsovian) by Oleksyshyn (1976) and Lyons (1985). Another florule, from southern Plainville (Lyons, 1985) apparently contains Linopteris palentina Wagner (figured as Linopteris obliqua in Lyons, 1985, fig. 11), and Pseudomariopteris cordato-ovata (figured as Mariopteris nervosa in Lyons, 1985, fig. 12). It either belongs to upper Westphalian D or to the lower Cantabrian, according to the senior author of the present paper. A higher Stephanian flora was obtained from Easton, Massachusetts. Although originally referred to the Westphalian D (Lyons and Darrah, 1978), it was reassigned to the Cantabrian by Lyons (1985). However, it may be as young as Barruelian (ex Stephanian A). The Easton flora of about 1000 specimens contains approximately one third pecopterid ferns and only about 1% lycophytes, proportions that are characteristic of the Stephanian. The following species are its most important constituents [as interpreted from the illustrations in Lyons and Darrah (1978) and Lyons (1985)]: Oligocarpia leptophylla (Bunbury) Grauvogel-Stamm et Doubinger (Lyons, 1985, fig. 15); Sphenopteris cf. hadrophylla Knight (figured as Sphenopteris minutisecta in Lyons and Darrah, 1978, figs. U, J), cf. Lobatopteris vestita (figured as Pecopteris lamuriana in Lyons and Darrah, 1978, fig. I); Pecopteris cf. nyranensis Nemejc [figured as Pecopteris arborescens in Lyons and Darrah (1978) and in Lyons (1985, fig. 14)]; and Sphenophyllum oblongifolium (Lyons, 1985, fig. 13). The age is assessed as Stephanian sensu lato (until the two pecopterid species can be reexamined), although Oligocarpia leptophylla is most common in the upper Stephanian (B and C stages) (compare Wagner and Sousa, 1985). Another Stephanian flora has been recorded from Seekonk, Massachusetts (Darrah, 1969; Lyons, 1985). The presence of Odontopteris brardii (Lyons, 1985, figs. 16, 17--the latter a laciniate Cyclopteris that was figured as Cyclopteris fimbriata, an apparent misidentification), together with Neuropteris desorii, Alethopteris grandinii (almost certainly Alethopteris zeilleri), Nemejcopteris feminaeformis, Polymorphopteris polymorpha, Pecopteris arborescens and Sphenophyllum oblongifolium (all listed but not illustrated by Darrah, 1969, p. 38) suggests upper Stephanian, although further evidence should become available before this point can be regarded as proven. A similar flora at Portsmouth, Rhode Island, studied by Lesquereux (1879-1884),Lesquereux (1889), is also listed by Darrah (1969, p. 37). Furthermore, several pecopterid and odontopterid species have been recorded from Pawtucket, Rhode Island. This locality was stated to contain the youngest known flora in the Narragansett basin (Lyons, 1985, p. 505)."

[Bguild]

Thanks for the info! Perhaps this is Pecopteris lamuriani?

[piranha]

1 hour ago, Bguild said:

Perhaps this is Pecopteris lamuriani?

 

 

The new combination for this species (Wittry et al. 2015) is Crenulopteris lamuriana, evidently it is absent from North America.

Send a PM to Jack Wittry.  Jack has written extensively on this subject and should be able to determine the genus and species.

 

Wittry, J., Glasspool, I.J., Béthoux, O., Koll, R., & Cleal, C.J. (2015)

A revision of the Pennsylvanian marattialean fern Lobatopteris vestita auct. and related species.

Journal of Systematic Palaeontology, 13(8):615-643  PDF LINK

[Bguild]

23 minutes ago, piranha said:

 

 

The new combination for this species (Wittry et al. 2015) is Crenulopteris lamuriana, evidently it is absent from North America.

Send a PM to Jack Wittry.  Jack has written extensively on this subject and should be able to determine the genus and species.

 

Wittry, J., Glasspool, I.J., Béthoux, O., Koll, R., & Cleal, C.J. (2015)

A revision of the Pennsylvanian marattialean fern Lobatopteris vestita auct. and related species.

Journal of Systematic Palaeontology, 13(8):615-643  PDF LINK

 

Thanks for the suggestion! I'll shoot him a message. 

 

That paper is interesting. It's sure makes things confusing when species names are overwritten. 

[Bguild]

Been having a bit of back and forth with some people on this one. Right now I'm in the Mariopterid camp, but am still trying to nail down an ID. Mariopteris nervosa is known from the Rhode Island Formation and I am noticing a number of similarities. Thoughts?

 

[doushantuo]

yeah,that i would love to have some Boersma at hand