Hallo Volker,

frag doch mal bei Erin Maxwell (Nachfolgerin von Ronald Böttcher) in Stuttgart nach.

Herzlicher Gruss

August

Dear Colleague,

The fossil in the photograph is not a Hypsocormus. Probably, it is a Pachycormus. You assign this specimen to Holostei. Pachycormiforms are not holosteans. At the present time they are interpreted as stem teleosts or Teleosteomorpha. There is an extensive literature on this subject. If you are interested, I can suggest you a few publications that can help you.

With my best wishes.

Pachycormus is indeed a member of the Pachycormiformes (an early radiating group of exclusivly mesozoic actinopterygians) and has a high interspecific variability.

For a recent overview (and examples of the the different morphotypes within the taxon) see: Wretman, L., Blom, H., Kear, B.P. 2016. Resolution of the Early Jurassic actinopterygian fish Pachycormus and a dispersal hypothesis for Pachycormiformes. Journal of Vertebrate Paleontology 36(5) DOI: 10.1080/02724634.2016.1206022.

http://www.tandfonline.com/doi/full/10.1080/02724634.2016.1206022

Thanks for the tip.  Volker has communicated with me privately and I am sending him pdf and reprints on the subject.

Dear Gloria & Jens C. Dieter,

thank you very much for your good informations about Pachycormiformes resp. the taxon Pachycormus. Now I have to study the special paleontological literature. With help of the differential diagnosis its probably possible to get the correct taxon of the fossil fish from "Ochsenhausen"!

With my best wishes, Volker   

I suggest that we focus our attention in Volker’s initial message/question. For what I understand, it is not his interest to get immerse in in the taxonomy of pachycormiforms, but his interest is to be able to identify the fish that he collected when he was 15 years old in the Lower Jurassic of Germany, specifically in the Holzmaden area. From this region four species of Pachycormus have been mentioned in the literature: P. bollensis, P. esocinus, P. macropterus, and Pachycormus sp. However, Sauropsis veruinatis and Hypsocormus sp. have also been mentioned and illustrated in the literature, based on specimens deposited in Museum Hauf (containing fishes from Holzmaden). There is no recent revision of the fish fauna from Holzmaden, less from its pachycormiforms, so that the last compilation on those fishes in from 1981. Certainly, the identification of Sauropsis and Hypsocormus in Holzmaden is in need of revision because those fishes are interpreted as Late Jurassic taxa. If I interpret the fish in Volker's photograph as a Pachycormus, then I am aware that the head and fins are damaged and I have no diagnostic elements to decide to which of the four species cited for Holzmaden it could belong. That is my problem, but certainly, others can have other opinion.

What is the difference between Pachycormiformes as stem teleosts (Teleosteomorpha sensu Arratia 2000, 2013) or as Teleostei sensu Mueller 1845 that corresponds to an apomorphy-based definition of teleosts? The use of one or other name is an author's preference depending on stem- or apomorphy- or crown-based definitions, not on synapomorphies. 

With my best regards.

Hello Gloria and Soledad,

thank you very much again! Yes, I'm not a specialist in the taxonomy of fossil fishes from the Lower Jurassic (my main interests are on the field of taxonomy and evolution of Miocene land mammals. Nevertheless, it is very interesting to follow your very kindly and professional explanations.

Yesterday, I studied a book called " Das Holzmadenbuch" (published 1981 by Dr. Bernhard Hauff, Holzmaden). There I found several photos from relevant findings of Pachycormiformes resp. Pachycormidae => 4 morpotypes (species) of Pachycormus are mentioned: P. macropterus (L. ~50-70 cm), P. bollensis (L. ~70-100 cm) P. esocinus (L. > 100 cm) and the small species Pachycormus curtus (L. ~30-50 cm). A first comparison (body shape and proportions) of my fossil fish from Holzmaden with the fotos of these species resulted in best agreements with the small species Pachycormus curtus AGASSIZ. For the time being, I will determine my finding as P. cf. curtus, because of the absence of helpfull diagnostic elements (damaged head and fins). During the next time I will check this first determination with of help of further paleontological literature.

With best wishes;

Volker 

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

Thank you all!

Results so far:

Dorsal and anal pterygiophores => the positions of these anatomic elements (the "real" fins are not preserved at my fossil fish) are looking more like Hypsocormus than Pachycormus!? My fish is very similar (body size, morphology, positions of "dorsal and anal fins") with a fossil fish (Hypsocormus sp.) published / pictured in the "Das Holzmadenbuch" from Bernhard Hauff 1981 (page 81, figure 98)!

At the moment, I will take (leave) the taxon cf. Hypsocormus sp. => I hope, you agree with this determination so far? And then we will see, if someone get involved with these old fishes (Pachycormus, Hypsocormus etc.) from Early Jurassic in future times and will give us good informations :-)

All the best;

Volker

Dear Volker,

Nice to hear your news. The most important and stimulant thing is that you have taken some time searching for information and trying to interpret your fish specimen using the available literature. In this particular case there is not much to compare, but you have arrived to a taxonomic identification using the few characters that the fish has for comparison. Fossils from Holzmaden are not well known and they are in need of revision. Fishes of the genus Pachycormus seems to be more common than the so called Hyposcormus sp. Please, take care of your specimen because it is a rare and valuable one.

All the best,

Gloria

Dear Gloria,

thank you very much again for your very friendly, interesting and helpful informations!

I'm glad, that I met you on ResearchGate :-)

All the best,

Volker