Paleobiology - Science topic

ni-hao

the wiser thing could be to collaborate with a palaeontologist. A fossil found ex-situ, i.e. outside the rock in which it was formed, can be tricky. Fossil can be reworked, i.e. become a fossil in a geological layer, which is subsequently eroded, with the fossil being redeposited in a younger layer. Geological maps are wonderful tools, but as any human design can be erroneous.

regards

Thanks for introducing this interesting topic!

Species is the building block in the systematics of Biology and Paleontology. So the’ gap’ between the two branches may be minimized with commonness in the facets of its definition. Paleontological species (with ambit spanning all past time planes other than the Recent) are morphospecies erected exclusively on hard part morphology that exhibits variations, and differs from other ‘look-alike’ morphospecies. The characteristic aspects of morphospecies are its stratigraphic occurrence and involvement in the changes of morphological features with time (cf. organic evolution and evolutionary lineage), save life activity. Paleontological species has the quality to be a phylogenetic species. On the other hand, the essential parameters of a biological species include sexual reproduction, interbreeding and reproductive isolation which are witnessed in ‘Recent’ organisms. Gene flow within the community is the most distinctive character of a biological species, which however, cannot document organic evolution. ‘Reproductive isolation’ due to geographical, behavioral or genetic differences is difficult to establish in fossil communities; moreover, it is difficult to adjudge if interbreeding of different fossil communities of a species reproduced fertile offspring.

Despite these differences, there are common areas that are to be explored to bridge the gap.

1. Extant species contains distinctive as well as common aspects of both paleontological and biological species and it records physiological and anatomical changes during the span of its geologic age. The changes need to be interpreted by both teams in terms of environmental, ecological, climatic and evolution to arrive at a common definition of species.

2. Fossilized dimorphic/trimorphic forms, conjoined (plastogamic) forms , adult-juvenile association in certain extinct species help in the recovery of life cycle with attendant sexual reproduction and gene flow through interbreeding. Such specimens though rare can be of joint interest; advanced techniques of DNA, RNA can be performed to know ‘blood relation’ between ‘partners’ and ‘offspring’. The will help in genetic classification of a species, which is the aim of both groups.

3. Fossil forms containing signatures of sexual reproduction in their hard parts should be treated on par with biological species, and these may be explored for genetic species based systematics.

best wishes,

Sanjay K. Mukhopadhyay

Dear Nicolas

Raising awareness and having a discussion on predatory journals and alike (depending on the definition) is a good thing, but I'm not sure whether RG is the best place for naming, shaming and listing.

Yet, I’ll share some thoughts and practices that pertain directly or indirectly to this matter:

When I receive an ‘invitation’ from a predatory journal (or should we say anti-scientific journal?), I immediately mark the sender in my spam filter. With a bit of experience it takes about 1/10 of a second to recognize such a journal. I currently receive just a few invitations per week and this was much more in the past, so I assume it helps.

Occasionally I check Beall’s list https://beallslist.net/ when I come across a published paper or publisher of unknown reputation to me. This is not full proof, but at least provides some information to consider.

For the field of paleontology, I occasionally browse through the excellent journal list of Kenneth De Baets in order to find a suitable journal to publish. https://www.gzn.nat.fau.eu/palaeontologie/team/wissenschaftler/de-baets/journals-for-paleontological-research/

If the name of a journal in the field of paleontology is not on this list, it may be a good indication of an anti-scientific journal. This list is particularly useful to early career scientists in the field, since it contains also information on metrics, like impact factors, and that is considered very important by our administrators and funding agencies (but rather unscientific – other discussion).

I once wrote a critical comment in the newsletter of The Micropalaeontological Society (TMS) on a specific new journal in the field of paleontology by a predatory publisher and called for a reaction by editorial board members including the Editor-in-Chief that were also (esteemed) TMS members (see pdf for details). Perhaps surprisingly, this reaction never came. None of the editors took a stand. Perhaps some or most did not even know they were listed as editor. On the positive side: the journal was terminated after some years for lack of submissions.

This brings me to a core problem with predator journals: as long as established scientists fall into the trap of being ‘honored’ by becoming an editorial board member we exacerbate the problem of predatory/anti-scientific journals.

I planned to keep this reply short – and utterly failed. I’m looking forward to seeing more responses.

No, Pentaxylales is totally different group, with a very typical or very specialized morphological as well as anatomical characters, which are not found in any group of fossil plants. It is also sometimes called or referred as 'Synthetic Group'.While other groups as you have mentioned, cannot too be clubbed into each other as each and every group has/have their characters of their own, which seperates them from each other. Birbal Sahni Institute of Palaeosciences, Lucknow, India;is the most apt, best and premier center with the largest data base (best library, best museum) in the world. I am very confident that your problem can be resolved at BSIP.

Jorge -

I think you might research "errors

-in-variables" models which I think look at errors in the independent variables by making repeated measures. Not my area, but it sounds promising here.

Also, have you considered heteroscedasticity?

For regression of form y = y* + e:  

https://www.researchgate.net/project/OLS-Regression-Should-Not-Be-a-Default-for-WLS-Regression

Cheers - Jim

Ken, what about George Poinar Jr.?

As discussed recently on the Ichnology Facebook page, these are inorganically produced structures. The author of Palaeotrochis, Ebenezer Emmons, wanted to discover fossils of "Taconic" (latest pre-Cambrian) age, and in this case found pseudofossils. His collection was destroyed in the American Civil War. They are certainly worth studying as pseudofossils, and it would be interesting to read a new article about them; however, they are neither body fossils nor trace fossils. See:

Hola Marcos, como te va?

Los guanacos tienen diferente numero, porque las hembras no tienen caninos, no se si se da en otros camelidos.

Los caballos también tengo entendido, pero no estoy seguro

Thanks for your answers! I was trying to convince an amateur collector that a particular tooth was not that of a dinosaur, but a mammal incisor.

The reason I stumbled on your post was b/c yesterday I was going through old papers on T. cruzi metabolism (1960's to 1990's) and was finding references to "Brazil" strain and I was checking it out myself. I'm sure that Minning et al's "Brazil" is the one I'm seeing in my references. Minning et al provides a reference for the strain, a 1982 article of S.C. Pan who describes it as a "low pathogenicity" strain and goes on to clone and grow it in culture. When he speaks of this strain he references three papers by himself, the oldest from the mid 1960s, so its my best guess as to when it was isolated. Thus, I have no doubt that Pan's "Brazil" is TcI b/c the evidence in Figure 3 in Minning et al is quite robust. The Brisse paper never actually analyzes "Brazil", it analyzes "Brazil NIH 1954" so I do not think it is a good idea to assume that they are one and the same. Also, I can't see the data for that experiment, so I can't determine how much I trust it, unlike in Minning where I do see the evidence. The good news is that in Brisse, the strain identities are listed as "available upon request" in the text, so if you are still not convinced you can contact the authors directly and learn the identity of "Brazil NIH 1954", which I'm guessing is a strain from Brazil isolated in 1954 and kept in some National Institutes of Health repository. Good luck!

Interesting...check with rweems@yahoo.com...

Jon

This trace impression showing :

1 -Rate of sedimentation with respect to time.

2-In upper and lower part decreasing and increasing size of width of digging materials

That happens when change in facies. Basically this type of structure occurs in sandy shore zone of marine environment where .That fossil can be skolithos or glassifungites.

Dear Volker,

Nice to know that you has found "Das Holzmadenbuch" because I was photocopying it to send a copy to you!  You have seen how magnificent those fishes look in the photographs in the Holzmadenbuch.  Still, I will send you copies of a few descriptions of other pachycormiforms that have been mentioned for Holzmaden, so that sometime, you should send me your post address in a message.  

With my best wishes. 

Gloria

Dear Volker,

At first glance, your material reminds me to a dipnoan jaw bone. See the attached photos for comparison (the photos correspond to Cretaceous Argentinian specimens).

All the best,

Sole

Dear Mohammed! This specimen looks like a small fish otolith, however I can not determine it. If so, You may contact with Werner Schwarzhans (https://www.researchgate.net/profile/Werner_Schwarzhans) or with Bettina Reichenbacher (https://www.researchgate.net/profile/Bettina_Reichenbacher).

Dear Mathew 

Seems to be this is  a Lumbar Vertebrae (L1 – L5 ). Supiror articular focet & focet for tubercle of rib are laterally  model . Transverse process have been damaged. You can check  most o f the  aves & some of reptile  families &  which one have better heart shape vertebral foremen.

Best 

Aravinda..!

moreover, consider size and mrtabolic rate to hipotesize on omnivory... several authors relate the small size in ornithischian dinosaurs as an indirect evidence of omnivory, together with anatomically plesiomorphic dentition. This kind of conclusions is arribed in Heterodontosaurids (See Sereno 2012) such as Heterodontosaurus (Norman et al., 2011), Fruitadens (Butler et al., 2010, 2012), Manidens (Becerra et al., 2013, 2016) and you can also look for this kind of reference in papers of feeding behavior in oprnithischia of Norman and Weishampel. I don´t remember if this kind of feeding is mentioned in Eocursor, Lesothosaurus, and stormbergia, but you can search the papers by your oun.

Cheers!

Hey Ranjeev,  Good question - and I bet that nobody really knows!  The problem arises that because of the often severe Ca limits to growth, the snails are probably constrained most of their short lives - so it might appear as indeterminate in a Ca-rich habitat, or determinate in a less Ca-rich environment.  Sorry that I cannot provide an easy answer - but that is the nature of the beast!  Good luck! 

May be Gyrostrea subtrigonalis (oyster). 

Quarzitic geoda with crystals, may be also with agate rim at the margin, it has nothing to do with fossils.

Dear Ranjeev,

That's a difficult question and there is no simple answer to it. Shell sculpture (as well as shape) can be both ecophenotypic and genetically fixed, depending on the environmental conditions and the presence or absence of competition and predation pressure.

For instance, in the Gyraulus species flock in Miocene Lake Steinheim the evolution of shape and sculpture is considered to reflect partly speciation and partly ecophenotypic variation (see Rasser 2013; attached).

In recent Melanopsis species of the Mediterranean, sculpture and shape are highly variable within single species, which makes species identification based on the shell alone sometimes almost impossible. Apparently, most of the morphological variability seems to be ecophenotypic (e.g. Glaubrecht 1993; Heller & Sivan 2002; attached). 

For another example, I suggest you also see Glaubrecht & Köhler (2004 and references therein; attached).

In summary, shell carination CAN indeed be a result of ecophenotypic plasticity but the difficult task is to prove it!

Best wishes,

thomas

I assume that these are closed chain kinetics.  If the vertical ground reaction force is known and joint kinetics (moments) are known then you could calculate mechanical advantage (in sagittal plane) by calculating the moment arms using the joint moment divided by the vertical ground reaction force for each joint and compare moment arms between the joints.  I understand that this may not be experimental data, but this method should work with experimental data.

I fail to see the spiral striae or the lateral furrows typical for Strigoceras on these photographs.

I am wondering if it could be Oxycerites species but those with stronger ribs are usually later than Bajocian. To my kowledge the Badamu Formation only goes up to middle Bajocian near Kerman (is this correct?) which makes it even less likely to be an Oxycerites.

Hi Victor,

While not my area of work, I read in this area as a hobby.  As a non-professional in paleontology, I would recommend Richard Fortey's book, Life. A natural history of the first four billion years of life on Earth. It is a fine book -- so well written -- and has as generous a section on Paleozoic (so, including Silurian) wildlife as any I have come across.

Dear Suman, I think apart of the methodology to clarify dominance in an specific assemblage, your question have some theory discussion. If you found an assemblage where a species is dominant you can not say that that assemblage is monospecific because you have other species. Even, if that species is 99.99% of the abundance is not monospecific because there are other species with the 0.01%. The only possibility to be an "monospecific assemblage" is when you only found one species and in that case I will not call that an assemblage is just a population of that species.

Zhang:

Without details of magnification and the source of the material nothing concrete can be said. Preliminary assessment rules out any plant or animal origin.

Best

Syed

Hakima:

I suspect this to be a piece of Crinoidal Limestone, though picture quality is not of desired expectation - Do check CaCO3 and other skeletal elements like Coral remains.

Best

Syed

Susheel:

Till Hakima furnishes age and locality of the specimens, it is advisable to have a look at this link for detailed insights about the related taxa.

Best

Syed

to Adriana Lopez-Arbarello: no pores, no aortal facets. The specimen is very fragmentary, and it only resembles me to an amiid basioccipital. :(

to Matija Križnar: size is nearly 2 cm, correct :) a basioccipital is also symmetrical in dorsal/ventral view, isn't it? But anyway, I will check the bones aforementioned by You, thank You :)

HI,

Please, read this article :

Pomar L., Morsilli, M, Hallock, P. et Bádenas, B. 2012. Internal waves, an underexplored source of turbulence events in the sedimentary record. Earth-Science Reviews, 111, pp. 56-81.

It can gives you more ideas.

Good luck

Jia:

This link with references therein should prove useful:

Best

Syed

A C4 diet indicates grasing, but only in the tropics. In the tropics many grasses, especially the savannah grasses, use the C4 pathway, while all trees use C3. However, outside the tropics most grasses also uses C3. For instance, the cows in Europe eat C3 grasses.

They could well be promising. It is necessary to remove a piece of the carbon layer, probably in the first instance using fine needles. They then have to be macerated with nitric acid probably with a little potassium chlorate added.  When they have turned a brown colour, they then need washing in ammonium hydroxide and then you should (with luck!) be left with the cuticle, which can be mounted on microscope slides for examination.  This is clearly a laboratory procedure and needs to be done with care.

To get larger pieces off, you need to macerate a piece of the fossil in hydrofluoric acid.  But that is nasty stuff and needs to be done by someone experienced in a lab specially set up with dealing with (and disposing of) that acid.

Hi Olesandr

Yes the size and shape reminds us of an Otolith.

Best

Syed

Check out this publication

Dear Xun

please see link below:

link 1: http://what-when-how.com/marine-mammals/mesonychia-marine-mammals/

also Zhou et al.  (1995) which is attached

Regards

Massih

According to Tatarinov the apomorphy of ornithodiras is mesotarsal articulation. This is the type of articulation when the joint is located between two rows of tarsal bones in contrast to crurotarsal articulation located between astragalus and calcaneus.

Dear Dr.Bulot, dear Dr.Fuchs

Thank you very much for your help!

Dear colleague,

The gross morphology of your microfossils reminds me of Bolboformids (microfossils incertae sedis) which are recorded and described from marine Eocene to Pliocene sediments. You may check: Spiegler, D. & Daniels, C. von (1991): A stratigraphic and taxonomic atlas of Bolboforma (Protophytes, incertae sedis, Tertiary). Journal of Foraminiferal Research 21 (2): 126-158 or Murray, J.W. (1984): Biostratigraphic value of Bolboforma, Leg 81, Rockall Plateau. Initial Reports of the DSDP LXXXI: 535-539.

Best wishes, Mike

Dear Paul,

You know very well that the terms 'biotite' and 'chlorite' include two very complex mineral groups that can be colored both very similar, and on the other hand, may occur in close parallel intergrowth.

In my experience, biotite and chlorite are distinguishable in the field work only in very specific cases:

1) The crystals (leaves) may not be strongly deformed (crumpled).

2) The crystals (leaves) may not be subparallel intergrown with each other.

3) The crystals (leaves) may not be strongly altered (discolored by oxidation, etc.).

4) The crystals (leaves) must be large enough so that you can stick with your fingertips or with a pair of tweezers.

If these conditions are met, then there is a trick in the field work to distinguish biotite- and chlorite leaves reliably from each other:

Biotite (and also muscovite) leaves jump into the starting position when trying to bend it or folding (elastic deformation).

Chlorite leaves remain in the bent position (plastic deformation).

Try it, you'll see: it works!

Best regards,

Guenter

I do not know whether these structures were made physically or biogenically. However, the term "tooth mark" is to be avoided because a "mark" generally refers to a physically made structure, while a "trace" is made biogenically. The term "bite trace" or "biting trace" is preferable to "tooth mark."

Even if spherical objects are quite common in the fossil record, these look very intruiging to me. I have, together with my colluege Mats Eriksson, done some work on spherical things we thought were Cambrian embryos. We used the micro tomography facility, TOMCAT, at the Swiss Light Source (SLS) in Switzerland. This non-destructive method is a brilliant help in deciphering the internal structures of fossil material. The data set consists of 100-2000 tiff images (i.e digital thin sections) that is combined in a 3D-program ( I am using Voxler3), whereafter you can detect morphologic features down to about 1 micron and spot internal structures in situ in great detail. If you are interested in having a go on this, we can run a few of your spheres the next time me or Mats have beam time at SLS. Interested?

Cheers,

Fredrik

Hi! I have been working with the Hirnantia fauna and it seems familiar to me, but I haven't found it in the associations from the Argentine Precordillera. Have you checked this paper?

Rong, J.Y., Huang, B., Zhan, R.-B. and Harper, D.A.T. 2008. Latest Ordovician brachiopod and trilobite assemblage from Yuhang, northern Zhejiang, East China: a window on Hirnantian deep-water benthos. Historical Biology 20: 137–148.

In figure 3 there is a damanellid indet that reminds me of it.

Do you have more specimens?

I think you could contact Robin Cocks, he has worked with this fauna many years and he is very kind. I think he will be interested.

Hope I could be of any help.

Karen

Hello!

I've seen quite a few papers on this topic on the Olexandr Kovalchuk's page.

You can have a look at his ResearchGate profile and publications, and maybe contact him and see if he's interested:

Really peanats?

History

The domesticated peanut is an amphidiploid or allotetraploid, meaning that it has two sets of chromosomes from two different species, thought to be A. duranensis and A. ipaensis. These probably combined in the wild to form the tetraploid species A. monticola, which gave rise to the domesticated peanut.[4] This domestication might have taken place in Paraguay or Bolivia, where the wildest strains grow today. Many pre-Columbian cultures, such as the Moche, depicted peanuts in their art.[5]

Archeologists have dated the oldest specimens to about 7,600 years, found in Peru.[6] Cultivation spread as far as Mesoamerica, where the Spanish conquistadors found the tlalcacahuatl (the plant's Nahuatl name, whence Mexican Spanish cacahuate, Castillian Spanish "cacahuete," and French cacahuète) being offered for sale in the marketplace of Tenochtitlan (Mexico City). The peanut was later spread worldwide by European traders.

Or do you actually mean Bambara groundnut?

In West Africa farmers were already cultivating a plant from the same family, the Bambara groundnut, which also grows its seed pods underground. Vigna subterranea (also known by its common names Bambara groundnut, Bambara-bean,[2] Congo goober,[2] earth pea,[3] ground-bean,[2] or hog-peanut[2]) is a member of the family Fabaceae. 

Dear Bastien,

This is an Eldonia, maybe an E. berbera (Alessandrello and Bracchi, 2003), from the Upper Ordovician of Morocco. This genus is well known from the Burgess Shale Fauna (Cambrian of Canada), the ordovician species from North Africa are the youngest members of this genus... Classification as medusae is not really clear, depending which author you will follow.

In contrast to the not very trustfull trilobite on your picture, the Eldonids and also the Scyphocrinites (Crinoid) are very well preserved specimens.

Best regards

Johannes

I may suggest you to contact Kevin Page: kevin.page@plymouth.ac.uk 

For model based Bayesian softwares I would definitely go for BEAST.

Hello Tayyeb,

I'm sorry to say that in my opinion, an identification based solely on the view given in this photo is nigh on impossible. For the positive identification of a species one needs  to see the shell or mold with ribs and whorls, and also views of the external side and the mouth aperture, or at least the molds thereof. Am I correct in assuming that the Badamu Formation is of lower Bajocian age?

I have however just found something here which may be of help to you:

I remember a poster at the SVP meeting in Berlin this year (2014) about the grasping capabilities of a non-maniraptoran coelurosaur:

SULLIVAN, Yu, Xu 2014, MANUAL FLEXIBILITY AND GRASPING ABILITY IN THE BASAL TYRANNOSAUROID DINOSAUR GUANLONG WUCAII. Journal of Vertebrate Paleontology, Program and Abstracts, 2014, page 237

Perhaps thinking about the hands of the sistergroup to Maniraptora within the Coelurosauria offers some interesting ideas.

edit: removed a typo

The Brackested Term is (SL/1.8)*h

The equation can be explained as follows:

The original Equation by Alexander, Langmann, and Jayes (1977) suggested for use in cantering or galloping animals

SL/h = 1.8*(u^2 / g*h)^0.39

(with u = Speed)

In Mammals SL/h is about 2.0 in the transition from walking to trotting and about 2.9 in transition from trotting to galloping.

According to Thulborn & Wade (1984) your use of

(1) V=[gh(SL/1.8h)^2.56]^0.5)

this Version instead of

(2) V = 0.25*g^0.5*SL^1.67*h^-1.17

(were in your case SL/h is 2.53/1.36 is 1.86) shows how important it is to use the the right equation. With Equation (1) the animal is about 30 km/h fast, with equation (2) it's a more moderate speed of 9.27 km/h

More recently there were studies that showed an even wider range of “hip height to foot length” ratios (e.g. This poster: http://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CDsQFjAD&url=http%3A%2F%2Fphobos.ramapo.edu%2F~erainfor%2Fpubs%2FManzellaECSCposter.pdf&ei=FylIVKSRHImCzAPevYC4Bg&usg=AFQjCNEFpOhqyIPn5jajrLvVZ-g-wxEU5w&bvm=bv.77880786,d.bGQ&cad=rja).

Even more fundamental critique derives from the difference in limb kinematics between dinosaurs and mammals (which were ultimately used by Alexander to derive his equation). (I remember a talk about this by Heinrich Mallison at Symposion about sauropod giantism at the centenary meting of the Paläontologische Gesellschaft in 2012, but all I could find on a fast search in the internet is the direct predecessor of the talk I remember; a talk at the SVP meeting in November 2011: http://dinosaurpalaeo.wordpress.com/2011/11/10/my-svp-talk-fast-forward-dinosaurs-part-1/)

P.S.: I hope I made no typo in the equations

Here are two additional papers, both freely available online:

http://socrates.berkeley.edu/~irmisr/nacotaph.pdf.

It is not in the Persian Gulf though, have you seen the work of Barbara Avezuela?

regards,

Gloria

Its not just your units that are wrong! the formula you give has powers (speed (m/s) = 0.25 x gravitational constant^0.5 x Stride length^1.67 x hip height^-1.17. But you numerical example implies you have multiplied everything.

Sent!

The correct binomen is Dromiciops gliroides, because Philippi described the same species in 1893 as Didelphys australis, a name preoccupied by Didelphys australis Goldfuss, 1809 (= “Pennants New Holland opossum, a phalangerid”, according to Hershkovitz, Ph. 1999. Dromiciops gliroides Thomas, 1894, last of the Microbiotheria [Marsupialia], with a review of the family Microbiotheriidae. Fieldiana [Zool.], N.S., No. 93, page 26; the identity of the latter species remains obscure, though).

You could measure the stride length for each step cycle - 3 consecutive imprints (or sets of manual + pedal imprints in case of quadruped animals) = 1 step cycle, 11 imprints = 9 step cycles - and then do an averaging over all step cycles (mean stride length).

If the trackway pattern shows considerable variation (e.g. curves) you should rather calculate distinct velocities for different parts of the trackway and discuss that.

Hi Arden

In the 1980's we did some paleobotany work out here in the Permian (Leonardian= Kungurian) of west Texas- Google Sergius Mamay. Also, see http://www.gigantopteroid.org/html/articles.htm . These may at least point you in the direction. I know this is somewhat later than what you are interested in.

Cheers

Kurt Stropoli

I hope This  given book may help you to get information on this present topic

I think you should also ask Margaret Collinson.

Thank you both so much for your help, this has really given me a good direction to go in.

This is a nice trace trace fossil, best refereble to Rhabdoglyphus Vassoievitch, 1951, not a body fossil. The photo isn't great (the lighting doesn't bring out details), and the specimen might be water worn, which perhaps obliterated some details of the transverse ridges at the top and bottom of the picture. The exterior of the specimen is dominated by transverse ridges and doesn't consist of the screw-like whorls of Helicodromites Berger, 1957. Nereites has a longitudinal central depression and two lateral lobes that consist of a series of leaf-like depressions. 

MacGabhann (hi, again!) correctly notes that identification really requires knowing if this is the top, side, or base of a bed (determinable in part by slabbing).

If the bottom of a bed (which seems possible), it is important that the six or so transverse ridges in the middle part of the trace below the large crack and "SSE" of the bottom of the yellow pen cap seem to show a steeper upper slope (to the top of the photo) and a more gentle slope toward the bottom of the photo. This sort of roughly cylindrical tube with transverse,  closely spaced ridges that mark the outer edges of invaginated "calices" occurs in relatively small traces (to 8 mm wide) on bed bases that are referred to Rhabdoglyphus ichnosp. b by M. Ksiazkiewicz (1970, Observations on the ichnofauna of the Polish Carpathians, p. 283-322, in T.P. Crimes and J.C. Harper (eds.), Trace Fossils, Geological Journal Special Issue 3, Seel House Press, Liverpool). The gentle curvature shown in the photo isn't reported in other Rhabdoglyphus, as far as I know.

R. ichnosp. b was reported to have a long range (Senonian-Paleocene) in 1970 in "flysch" facies, but maybe runs higher.

Vallon's observation that the trace seems to be composed of backfills is borne out by the sections through the backfills at the top of the photo.   

It is true that the botanical taxonomy is mainly based on sexual characteristics and to identify a specimen, often can be available the information of the whole plant. Traditional keys are often supported in these sexual characteristics, thereby providing taxonomic information (such as order or family). Consequently, in addition to its primary function of identifying a specimen, the keys provide support for taxonomic assignment. But this kind of traditional keys has a limited role in many cases.

The alternative is the field keys (see for instance Lawrence & Hawthorne, 2006) based on the best characters for the determination rather than the best characters for the taxonomy. For example, in tropical trees is often difficult to see the flowers, so that the determination must be based on features of the leaves, bark or even other as odors. There are other examples, such winter woody plants keys (for example Schultz, 1999 ) based on characteristics such as morphology of the shoots or leaf scars. The latter, relatively speaking, would not differ too much from a genus-form.

Therefore, I agree that traditional classification schemes are not applicable to fossil plants, but it could be possible to generate keys designed specifically for form-genus, applying field-key schemes and targeted to the species (that is, leaving aside the taxonomy unless it is linked to useful features for identification).

There is a variety of studies. Some of the past 10 years:

Regards,

Joachim