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I recently decided to try a new (for me) method of preparation which involves dissolving away bone in hydrochloric acid. This method was used on the specimens published in various papers on the Hunter Siltstone, an important Devonian fish locality in NSW. Fossils are dissolved in hydrochloric acid, leaving an impression of the bone which is then cast in latex and/or resin. This method is used because the rocks tend to split right through the bone itself, so you miss a lot of the features present on the exterior. After a cast of the specimen is made, it can be coated in black ink and photographed with a coating of ammonium chloride so all the details are clearer. Here is the specimen I decided to try - a partial acanthodian jaw. This is what it looked like as split, just a cross section of the bone. The first step is dissolving away the bone in hydrochloric acid. I don't have any photos of this step but I just used a store bought bottle I had laying around, not watered down or anything. I think it took 2-3 days for all of the bone to dissolve away on this specimen. Keep in mind hydrochloric is nasty stuff, definitely best to wear gloves, avoid splashing it and use it in a well ventilated space! After leaving the rock to soak in water for a few days after the acid bath, I was ready to make a latex cast of the impression. The first coat of latex should be super thin to ensure as much detail as possible is captured. After the second or third thin layer, I started to apply thicker layers. The latex I used ended up being from 1999, it was only bought a few years ago so mustn't be in very high demand! Here is a photo of the latex cast and the finished specimen. In the second photo I applied a coating of indian ink for good contrast when I eventually applied ammonium chloride for photography. This was my first time using ammonium chloride so it took a lot of attempts before I was happy with my results. I'm still a bit unsatisfied, not sure if it's because of the ammonium chloride itself or if it's just showing up imperfections in the cast more. This ended up being an ischnacanthid acanthodian jaw, either Grenfellacanthus or something new. Have linked the Grenfellacanthus paper here for those interested: LINK
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Acanthodian and Placoderm Fins/Spines from Red Hill
Jeffrey P posted a gallery image in Member Collections
From the album: Upper Devonian
Acanthodian and Placoderm Fin/Spines Upper Devonian Catskill Formation Duncannon Member Red Hill Hyner, PA.- 1 comment
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From the album: Misha's Late Devonian Fossils
Partial Gyracanthus spine. Late Devonian, Catskill Fm., PA.-
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I managed to actually take a vacation last weekend and meet up with our very own Tim and Paul to collect Late Devonian verts from PA. I first met up with Paul at Red Hill. When I first arrived at the site I didnt know the person there was him. So I parked and walked into the ditch at the base of the road-cut and immediately spotted a strange form in a piece fallen from above. As it turned out it was a Gyracanthus spine! Gyracanthus sp. Turns out the mystery collector was Paul, who was kind enough to give me a rundown on the site, its geology, and show me the awesome finds he had been collecting. After being there for twenty minutes I was impressed by Paul's fortitude - it was hot, very hot! Red Hill is a difficult place to collect, with the best stuff coming from only one small band of sediments. One must spend hours removing overburden and working the layers back to find the sparse good finds. Paul is exceptionally well versed in the Upper Devonian Catskill material and is a great guy to collect with, even inspiring me to climb up and join him on the side of the cut. Unfortunately the heat was too much for me and I came down after only a short time. A friend of his stopped by, who had several decades of collecting there. His name was Doug and he took me to the small museum in the nearby town to see the Red Hill material that he had collected there. As soon as I figure out how to upload the photos from my phone I'll share pics of the place..it was neat; there has been some incredible things from that site. Afterwards I returned and met up with Tim there (who is also knowledgeable and fun to collect and hang out with. ) My overall impression of Red Hill: Very interesting site, best visited in the fall or early spring, requires dedication, perseverance and patience though to find the good stuff. The next day I rode with Paul to meet up with Tim, Dave Broussard a Professor at Lycoming College, and another teacher named Chris (I didnt get a chance to speak to Chris much unfortunately.) We met at a quarry near Canton which exposed more of the Catskill. Unlike Red Hill, there were fossils every where! And they were all vertebrate fossils too! My first good find is this plate with numerous juvenile (fingerling) Bothriolepis median dorsal plates and head plates. Bothriolepis sp. I learned later when working on this plate that a partial pectoral is also present (but I havent taken a pic yet.) I also found this tooth (impression) of an unknown lobe fin fish I also found a large section of skull plate most likely from Hyneria Scales are the most common fossil at this site. This is a large example (though I cant remember the genus.) By far my best find is a section of jaw from a ischnacanthid acanthodian. When I found this there was only one other from this site, so I donated it to Dave for his research into these fish. Shortly afterwards one was also found by Paul. The teeth were not separate from the jaw bone in the ischnacanthids, though, they were made of dentin. It is doubtful if they could replace a broken tooth. I'll be adding more finds from the quarry as I finish photographing them and cleaning them. We stayed at the quarry til noon, after which Paul had to leave. Dave was kind enough to show Tim, Chris and myself the location of a productive road cut where many scales and placoderm plates could be found. Though he and Chris left after showing us the site, Tim and I collected for a bit. I did pretty good there (as did Tim.) Pieces of the placoderm Turrisaspis were very common. This is the dorsal median plate of one (the dorsal fin if you will) and close-up part of another one This one has the spiny "leading edge" of the pectoral "fins" as well as a partial plate of the rarer placaderm Phyllolepis With the exception of the Phyllolepis bit, all are Turrisaspis sp. Heres an awesome model of Turrisaspis by C. Fredrick Mullison As I work on trimming the blocks I keep making accidental finds, Like these partial Hyneria teeth The top tooth is 1.5cm and the bottom is 13mm. Hyneria sp. And these unidentified fish teeth are fairly common as well . They are considerably smaller and more round for piercing unlike the hyneria teeth which have a sharp edge on the blade. Its not uncommon for the tips to break Thats it for now, Ill keep posting pics as I clean them.
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Hi Everyone, I’d like to share a few posts on the shales I’ve been hunting recently in Kansas City, Missouri. Long story short – my neighbor is digging a ‘pond’ to China. He has massive equipment from his business and so far he’s dug through about 35 feet (~10.6 M) of material. My land matches his where the dam to the pond is and I saw shale in it which really surprised me since I’ve never found shale on my property. Even in the creeks and gullies. I would also like to say that I have been really inspired by the posts from @connorp and @deutscheben about the shale they find in Illinois and wanted to show a similar collection from a specific location/member in Missouri. Here’s a rough Lithology table of my area: The pond was dug through the Winterset Limestone member through the Stark and I believe through the Galesburg shale members and into the Bethany Falls Limestone from the top of the hill we both live on! It’s absolutely magnificent. I asked him if I could take some of the shale that he went through and all he said was, ‘take it all,’ and so I did. I passed on the limestone since its way more readily available to collect in the area and I hadn’t ever hunted through shale. I’ve gone through about 250 lbs (113 kg) of shale within the last few weeks and would like to sporadically present my findings as I can make time for it. Completely unrelated to his digging I listed and sold my house and land and am moving my family to Texas. All of this has happened within a month or so. I feel that this last hurrah into shale is a way for me to say goodbye to the state I’ve lived almost my entire life in thus far. Here’s one of my wheelbarrow loads of shale. I am no scientist but will do my best to assign at least some family or species to my finds. I love the adventure of findings fossils, prepping them can be therapeutic at times and insanely frustrating at others, and assigning species is my least favorite. Probably because I am not naturally good at it. If you see a species you feel is wrongly identified please feel free to share. It’s my weak point so I’d appreciate anything that helps me get better at it. The Galesburg layer is really hard to hunt from because it’s mudstone/claystone at the top then turns into harder grey shale at the bottom. It brakes vertically into rounded blocks instead of horizontally when you try to cut or split it and destroys the fossils that it contains. At the slightest addition of moisture it crumbles and the paper thin fossils are lost. This is a chunk of it I accidentally left out one night that succumbed to the dew from one evening and following morning. It’s filled with material I am having a hard time placing but I am calling it plant material until I can more accurately identify it. Unfortunately I didn’t get hunting till a few weeks after this layer had been dug out and the vast majority if it returned to mud. Without future ado, let me begin my adventure into Missouri shale. Here’s what I believe may be part of a Calamites plant. From what I am calling the Galesburg claystone. Scale in cm/mm. Here is another unknown that I believe is some type of plant stem. The Galesburg material is so much harder to deal with that I have a lot of it in storage now to go through at a later point.
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This past Monday, during an outing to a quarry with Dave Broussard, our very own Tim (Fossildude19) and Paul (Paul1719) in PA. I found a partial ischnacanthid fish jaw. As it was only the second known from that location I donated it to Dave for study. A few moments later Paul found one too! He also donated his. It was interesting and enlightening watching a professional photograph and preserve it before removing the part of the slab it was in. Dave is a professor at Lycoming College in PA. and a vertebrate paleontologist. Ischnacanthids had a primitive arrangement when it came to teeth (though some argue it was more advanced than we give it credit for.) The teeth were a part of the jaw, though still made from the dentin bone material in the jaw. They did not appear to be able to regrow them as far as we know. This specimen has two partial teeth and one complete one. Im hoping to read Dave's research on the subject when he publishes it. The photo is courtesy of and copyrighted Dave Broussard. *I accidentally put Acanthodians had a primitive arrangement..I meant ischnacanthids ( a type of acanthodian.)
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Over the past year, I've become fascinated with the often bizarre fish and sharks of the Pennsylvanian. Fortunately, my home state of Illinois is a great place to hunt for such fossils. I've shared several of these in other posts before, but wanted to put everything together in one thread. Probably won't have much to post for a few months after this, but once summer rolls around, I should hopefully have plenty of new finds to share. I would say there are three major settings in which you can find fish fossils in Illinois: Mazon Creek, black shales, and limestone. I have not had luck at Mazon Creek yet, but hopefully that will change. So I'll start out with the black shales. These specimens, my first fish fossils, were collected in August 2019 from the Mecca Quarry Shale exposed at a clay quarry in Utica, IL. This shale directly overlies the Francis Creek Shale (i.e. Mazon Creek) at this location. The three specimens below are stomach ejecta from some kind of fish, and are composed mostly of partially digested fish scales. In addition, I found this very nice pair of associated acanthodian fin spines. The top fin has an area showing damage, possibly due to predation.
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So an interesting summer. As some of you might know, Parks and Recreation came down hard on the Red Hill site while I was working there. At some point, the site had been transferred to Forestry, ya go figure. So there has not been an active permit for some time. But I was homeless and in need of a project so I was able to connect with Prof. Dave Broussard of Lycoming College and shift my focus to the sites along Rt 15 north of Williamsport. Still Catskill although the exposures at Powys Curve are Sherman Creek (Frasian) member instead of the Duncannon (Fammenian). I had collected there with my son Ian a while ago but was at one of the less productive sites I've been visiting this summer. This is the find of the summer (maybe lifetime). It is a Tristichopterid, like Hyneria. Its at the Academy of Natural Sciences in Philly and just being described now for a publication by Ted Daeschler.
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Preparing acanthodian fossils from the Tillywhandland quarry.
James_R_V posted a topic in Fossil Preparation
Did some fossil hunting at the tillywhandland quarry near Forfar during the weekend and found of partially exposed acanthodian fossils. I just wandering if anyone could give me some advice on how to expose the fossils without damaging them. Someone mention that I could use acid to expose them, but I have been reading that potassium hydroxide could do just as well. The fossil are in clastic carbonate laminates.- 3 replies
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A new study led by the American Museum of Natural History (AMNH) provides the strongest evidence to date that sharks arose from a group of bony fishes called Acanthodii (‘spiny sharks’). Analyzing a well-preserved fossil of Doliodus problematicus, a sharklike fish that lived 400-397 million years ago (Devonian period), John Maisey and co-authors identified it as an important transitional species that points to sharks as ancanthodians’ living descendants. http://www.sci-news.com/paleontology/sharks-acanthodians-04706.html
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Hello, this is a fragment of a large acanthodian spine. Length about 16 cm, width up to 2,4 cm. All I know is that it's from the devonian of the Maider area in Marocco (scale = match = 45 mm). Does anyone know more about that material from Marocco? (Genus, more precise data about the stratigraphic age?). I think it's probably Machaeracanthus, but I'm not sure. Thanks, araucaria1959