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Found 171 results

  1. Hi everyone I think I just found a new hobby With my latest fossil delivery I recieved quite a lot of microfossils & matrix vials as the world of microfossils was something that I have been long interested in. So a 2 weeks ago I finally ordered my first microfossils for which I reserved a special drawer in my archive cabinet. So here is a recapp of what I all got: 3 vials of permian material from Waurika, Oklahoma 1 vial of permian material from The red beds of Archer County, Texas 1 small vial of Conodont rich Mississippian material from the Chappel Limestone formation, Texas 1 small vial of Cretaceous Lower Gault Clay, East Wear bay, Folkestone, Kent, UK A micropalaeontology slide with Jurassic Blue Lias matrix rich in holothurian material. A thin section of an Ostracods filled Elimia snail from the Green River Formation in Wyoming A thin section from the Rhynie chert of Scotland which should contain preserved parts of the plant Aglaophyton major and perhaps even other species. I also got a lot of Bull Canyon micro fossil teeth and 2 cretaceous mammal teeth from Hell Creek In this topic you will be able to follow my path through this newly discovered hobby as I will post my finds and progress Currently I am only working with a clip-on cellphone microscope, but I do plan on getting a professional microscope in the next few months! (Tips are always welcome) So let's put on our Ant-Man suit and explore the microfossil realm So here are some of the first pictures I made of some of the microfossils Starting with the thin slices! Thin slice with Ostracon filled Elimia tenara snail from the Green River Formation, Wyoming Thin slice with Aglaophyton major from Rhynie Chert in Scotland
  2. Hi! I recently aqcuired quite a lot of "microfossils" to kick off my Triassic collection, as I personally find it one of the most interesting time periods and while I am aware possibly not all of them are ID'd correctly I just wanted to get some nice fossils from this time period regardless of their ID's. All the fossils I acquired are from the Bull Canyon Formation, Dockum Group, San Miguel County, New Mexico, USA (Norian age) But I myself am not very knowledgeable yet in this material as I just started my collection but I am aware that some if not most of the ID's on these fossils given by the seller might be wrong as everything I read about the Bull Canyon formation says that the formation isn't that well discribed yet. I tried to make the photo's as good as I could, but it wasn't always easy given their extremely small size, so I hope the quality is good enough to work with. So I am kinda hoping is someone here on the forum would like to give it a try to see if he/she could confirm or disprove given ID's. Thank you in advance! The first set of 2 teeth were listed as the Phytosaur "Pseudopalatus" teeth which after doing a bit of research is considered a junior synonym for "Machaeroprosopus" The next collection of 3 teeth were listed as the Pseudosuchian "Revueltosaurus" The next tooth was listed as a "Theropod indet" tooth, and I know there are at least 2 species of theropod present at Bull Canyon, a Coelophysid called Gojirasaurus and a herrerasaurid called Chindesaurus. But I am not even sure whether this tooth is dinosaurian or not. The next set of teeth were listed as "Arganodus" lungfish teeth And the final tooth was listed as a "Sphenodont" (Rhynchocephalia indet.) tooth with affinities to Clevosaurus (which is found in Nova Scotia, Great Britain and China)
  3. Hi! I recently acquired a few new additions to my permian collection, but there are a few pieces of which I am not a 100 % whether they are ID'd correctly, simply because I am not yet knowlegdeable about the material. So I thought it might be a good idea to post the ones I am doubtfull about here, as I know there are a lot of people more knowlegdeable than me who probably could ID them. The first item is a small claw listed as "juvenile dimetrodon limbatus" from the Red Beds, Archer County, Texas, USA I was a bit doubtfull when they said "juvenile" dimetrodon claw, but I got it anyway because it's a very nice permian claw which was an okay price regardless the ID. The second item is a caudal vertebra that was listed as "Edaphosaurus" (from the Archer City Formation, Red Beds, Archer County, Texas, USA) which came as a set along with a piece of sail spine which without doubt belongs to Edaphosaurus. The last items were sold as a collection of "Eryops megacephalus" fossils from the Wellington garbar complex, Waurika, Okhlahoma. From left to right are a piece of skull plate, a toe bone, a piece of dermal armor and a tooth.
  4. https://www.geek.com/news/scientists-discover-tiny-fossils-of-oldest-known-frog-relative-in-north-america-1776396/?source=science
  5. Foraminifera for Christmas

    The Nerdiest Christmas Cards Ever May Be These Microscope Slides Composed of Shells The unusual holiday exchange, which lasted decades during the early 20th-century, hints at the drama between the two colleagues Smithsonian By Allison C. Meier, December 17, 2018 https://www.smithsonianmag.com/history/two-scientists-exchanged-christmas-greetings-microscope-slides-180971049/ A century ago, two scientists exchanged fantastic microscope slides as Christmas cards https://boingboing.net/2018/12/17/a-century-ago-two-scientists.html Yours, Paul H.
  6. Foraminifera for Christmas

    The Nerdiest Christmas Cards Ever May Be These Microscope Slides Composed of Shells The unusual holiday exchange, which lasted decades during the early 20th-century, hints at the drama between the two colleagues Smithsonian By Allison C. Meier, December 17, 2018 https://www.smithsonianmag.com/history/two-scientists-exchanged-christmas-greetings-microscope-slides-180971049/ A century ago, two scientists exchanged fantastic microscope slides as Christmas cards https://boingboing.net/2018/12/17/a-century-ago-two-scientists.html Merry Christmas everybody, Paul H.
  7. G'day everyone! My dad and I were interested in investing in a USB Microscope to take photos of our smaller fossils and other things (Mainly small insects). We did some searching about and found this microscope. Before I purchase it I want to see what you all think and if there is a better option. https://www.online.com/p/AmScope-UBW500X0200M-5x-500x-2mp-8-led-3d-Zoom-Digital-USB-Microscope/2255356843 Thanks, Dan
  8. Retracing Antarctica’s Glacial Past LSU geologist uncovers new data to inform future sea level rise https://www.lsu.edu/mediacenter/news/2018/09/25gg_bart_scireports.php https://www.sciencedaily.com/releases/2018/09/180925140417.htm https://phys.org/news/2018-09-retracing-antarctica-glacial.html The open-access paper is: Bart, P.J., DeCesare, M., Rosenheim, B.E., Majewski, W. and McGlannan, A., 2018. A centuries-long delay between a paleo-ice-shelf collapse and grounding- line retreat in the Whales Deep Basin, eastern Ross Sea, Antarctica. Scientific reports, 8(1), article 12392. https://www.nature.com/articles/s41598-018-29911-8 Yours, Paul H.
  9. Looking for a Stereo Microscope in Europe

    Hi everyone! I'm looking to buy a Stereo Microscope in Europe for microfossil observation and was wondering if anyone can point out recommended brands. The price range for me is <400 Euros. Thanks!
  10. Fossils from Pilatus mountain

    Dear TFF members, I have just returned from the trip to Austria and Swizterland and I need help in identifying the ones I found on the top of Pilatus mountain. From what I've read, Pilatus is made of Cretaceous rocks. To me they look like some sort of microfossils - I'm afraid I cannot take any more detailed photos with my camera, but I hope someone here will be able to make out what it is anyway
  11. Some Judith River IDs

    Here are some small fossils I found back in the summer of 2017 in Montana up in the Judith River Formation. 1. Small reptile vertebra? (.5 cm) 2. Assorted tiny bones several of which are likely from birds. 2a. Hollow at the broken end (about .8 cm). 2b. Hollow at both ends (1.2 cm). 2c. Hollow at both ends as well, looks like limb bone. (1.5 cm). 2d. Appears to be hollow on both ends (.7 cm).
  12. 2017 Wyoming Microsite Finds

    Last summer on my trip out west, I found these teeth at a Lance Formation microsite in Wyoming. Many of the fossils were found through splitting a yellowish-orange concretion filled matrix, while others were free from it. This site was on the same ranch where I found my theropod hand claw but in separate locality. It's rather late (EST) at the time I'm posting this but wanted to show some of the teeth I found and was hoping I could get some help identifying them. 1. Pectinodon bakkeri 2. Richardoestesia sp. (?) 3. Lizard/ Worn Herbivorous Dinosaur Tooth (?)
  13. Keeping track of tiny fossils has been difficult for me, but penny holders have been a real help. I have begun using picture frames to hold and display my fossils in penny holders. These frames are 5x7 inches. The primary use I have made of the holders is for small pieces of shale each of which contains a conodont.
  14. Bunch of micro-mollusks

    Hi all, A handful of days ago there was a sand pile right in my neighborhood. Not sure why it was there, probably someone was making constructions to their house, but in any case I was happy. That's because that kind of sand comes straight from the North Sea, which is full of Eemian fossil sediments! So I took a little plastic bag and spent an hour or two looking in that pile of sand for fossils. The very common Eemian bivalves came up abundantly (so species like Mactra plistoneerlandica, Cerastoderma edule, C. glaucum, Macoma balthica, etc), but that is not what I was too excited about. Seeing that the sand pile was rather small, it forced me to focus on just that little pile. Which is great, because therefore I actually started looking much more closely, and hereby also collecting tiny micro-fossils! Lots of gastropods, which is awesome because these are not as common as bivalves in these sediments. I namely found a complete yet puny Anomia ephippium, some very small Cerastoderma's, and also the ones attached. I would love to be able to bring these down to species level. So I am asking for your help! The Hague, Netherlands (from North Sea sediments) Eem Formation Eemian, Pleistocene; 120'000 y Thanks in advance, Max #1: Looks a little bit like Macoma balthica, but still a bit different... Very likely from the Tellinidae
  15. Since the upload of Part 1 succeeded, I'll now offer up Part 2, a look at two interesting taxa from the family Globigerinidae. This family contains most of the taxa that we associate with the idea of "planktonic forams", perhaps due to our familiarity with the "globigerina oozes" that form a significant part of the floor of the modern world oceans. Globigerinoides ruber (d’Orbigny, 1839) is one of the two “red” species of globigerinids, as the specific epithet indicates. It is well-known that the color of individual specimens varies from white to pinkish-red, and it is typically the case that only some of its globular chambers exhibit the red coloration. I have specimens with all white chambers, one red chamber, two red chambers, etc., and have a single individual that is all red. Interestingly, the intensity of the color seems to increase with the number of chambers affected, so the all red specimen is very red indeed -- it is also a little smaller than average. Here is a typical specimen seen from the umbilical side, in a slightly oblique view, showing the primary aperture and one red chamber: The genus Globigerinoides differs from Globigerina in that its species exhibit secondary apertures, formed at the junctions of the spiral suture with intercameral sutures: Here is the spiral side of the same specimen, again presented in an oblique view, with two supplementary apertures, two red chambers at the left, and a pale pink one at the right. The top, final chamber is white, as is most frequently the case. This taxon is the commonest foram in the sample, by a large margin. The other red globigerinid is Globoturborotalita rubescens (Hofker, 1956). According to the World Foraminifera Database, it also occurs in the Gulf of Mexico, but I have seen no specimens in my sample as yet. This taxon shows four chambers in the umbilical view, rather than three, and lacks the secondary apertures. A second interesting globigerinid, quite different from the preceding, is Globigerinella siphonifera (d’Orbigny, 1839). This genus exhibits planispiral forms, rather than trochospiral -- all of the chambers are in the same plane. (Actually, the test begins growth in a trochospire, but quickly switches growth pattern to planispiral.) There is a primary aperture at the base of the final chamber, and in fully mature specimens like this one, the initial chambers enter the final one through the primary aperture: The final chamber appears to be “gobbling up” the initial chambers, like the snake that swallows its own tail. In Part 3 of this entry, I’ll examine three taxa from the Family Globorotaliidae. Stay tuned.......
  16. Planktonic Foraminifera are particularly important in biostratigraphic studies and correlation, as they are ubiquitous in marine deposits, and evolve rapidly. They first appeared in Middle Jurassic time, and thus have a long geological history. There are many phylogenetic and correlational studies available, and their rapid evolution makes them exceptionally useful as temporal markers, or guide fossils. I am currently looking at planktonic Foraminifera from a deep-water sample that was collected from the Dry Tortugas Islands, off of the coast of southern Florida. The sample was dredged from a depth of 215 meters, due south of the islands. This is an interesting area, as it represents the eastern extremity of the Gulf of Mexico, as well as the northern edge of the Caribbean Sea. The sample is a very rich one, with numerous species of benthic Foraminifera, as well as a few ostracodes. There is a good selection of planktonic forams -- I have thus far identified ten species, and would like to discuss one of these, a member of the Family Pulleniatinidae. Pulleniatina obliquiloculata (Parker & Jones, 1862) is a rather unusual looking taxon, starting with a trochospiral growth pattern, but switching to a streptospiral pattern for its final chambers. It is globulose, and quite shiny, making it easy to recognize. It took me some time to locate a specimen for imaging, as most specimens have their aperture clogged with matrix. The aperture is low, but very broad, and the apertural surface of the chamber below it is strongly pustulose. If this image were rotated toward the viewer a bit it would be clear that a thin area just above the lip of the aperture (seen here as an imperforate band) also bears pustules, although they are not as strong as those beneath the aperture. For those interested in taxonomy, this species is the generotype of Pulleniatina. I am submitting this short blog entry to see if the recent problems with uploading to the forum have been fixed. If so, I'll be submitting other entries on this sample.
  17. The Lomita Marl Member of the San Pedro Formation is a well-known source for Middle Pleistocene marine fossils, and its beautifully preserved molluscan fauna has been treasured by fossil fanatics for decades. There are outcrops in the city of San Pedro, California, although many of the "classic" localities have been destroyed by urban development. It is well-exposed in the Lomita Quarry, located in the Palos Verdes Hills northwest of the city. It has been dated at 400,000 to 570,000 years ago, about equivalent to the Santa Barbara Formation, which occurs further north along the California coast near the city of the same name. The Lomita Marl is also an extremely rich source for microfossils, as ostracodes and forams are both very abundant and easy to extract from the matrix. Most taxa in these two groups are still extant off the southern coast of the state, but a significant proportion of the fauna appears to be extinct. (One must hedge here, as the ostracode fauna of the Pacific coast of the United States is not very well known; the forams are better documented.) A small sample of washed residues has given me the opportunity to begin study of this interesting fauna, and I hope to show some images of taxa from both groups on this blog. This first entry will look at four ostracode taxa, selected simply because they are relatively easy to identify. (Much of the ostracode fauna is known only in "open nomenclature", as in "Aurila sp. A", meaning that the species has not been recognized or is undescribed.) Bythocypris elongata Le Roy, 1943 is easy to recognize. It is common, and appears to be the only member of the genus to be found in the Lomita. It is a member of the family Bythocyprididae, which are smooth, and some would say "uninteresting" as a consequence. As is normal in the family, the anterior end of the valve is broader and a bit more inflated than the posterior end. The remaining three taxa are all members of the large family Hemicytheridae, a group with interesting surface ornamentation: Aurila driveri (Le Roy, 1943) is one of the several members of the genus to be found in the Lomita, and the only one (as far as I am concerned), that is easily recognizable. The high-arched dorsum and strong ventral flange place it in the large genus Aurila, and the prominent anterio-ventral teeth are characteristic only of this species. The caudal process is low on the posterior margin, and bears fine denticles. Australicythere californica (Hazel, 1962) is relatively large at roughly one millimeter in length, and is more elongate than most hemicytherids. There is no caudal process, but typically 3-4 large posterio-ventral teeth. The lower half of the anterior margin has some small denticles, rather worn on this specimen. The valve outline is quite distinctive for this species. Hemicythere hispida Le Roy, 1943 is probably the easiest ostracode from the Lomita to identify, and is quite abundant. This image does not do it justice, due to the lack of 3-D. Under a stereo microscope it looks almost "furry", as the entire valve surface is covered with round-ended tubercles. (The lack of 3-D here is due to the excess white matrix obscuring all but the ends of the tubercles.) This species also has a particularly prominent eye tubercle, seen here at the anterior edge of the dorsal margin -- under the microscope this tubercle appears somewhat shiny, rather like glass. (I had to sacrifice the shine to get decent illumination of the rest of the valve.) To make these images, the specimens were simply laid flat on the inside of the lid of a micromount box. Not very sophisticated, but it gives a nice black background -- at the expense of making the specimen a bit more difficult to illuminate evenly. And it's quick and simple........... That's it for this entry. I will try to illustrate some of the many forams to be found in the Lomita in a future blog entry.
  18. Here is my collection of small/micro fossils from the Arkona formation in Southern Ontario. Everything here was collected by soaking clay from the Arkona fm and sifting out the solid matrix. I'm sure many of my IDs are way off so please correct me and fill in the unknowns if you recognize anything! Tentaculites Bactrites sp. Left: Tornoceras sp. Right: Maclurites? sp. Left: Holopea? sp. Right: Nanticonema lineata Left: Hormotoma? sp. Right: Platyceras sp. Left: Scaphopods Right: Hyoliths Left: Paracyclas lirata Right: Prothyris? sp. Left: Nuculana rostellata Right: unknown Left: Nuculites triqueter Right: Nuculites pacatus Left: unknown Right: unknown Left: Spirifer sp. and Delthyris sp. Right: Chonetes sp. Left: Cyrtina sp. Right: Cyrtina sp. Left: Camarotoechia sp. Right: Camarotoechia sp. Left: Onniella trigona Right: unknown Left: Terebratula sp. Right: Productella spinulicosta Ostracods Left: Eldredgeops sp. Right: Eldredgeops sp. unknown blastoid Devonaster? sp. arm fragment crinoid fragments
  19. Hi, I've recently fully processed some matrix from the Lower Hamstead Mbr. that I collected back in November, and I thought I'd share some of my finds in a similar way to my Bembridge Marls Mbr. material. The matrix originates from a 'shelly' horizon in the Lower Hamstead Mbr. and was collected from fallen blocks at the base of a low cliff exposure at Bouldnor Cliff. The Lower Hamstead Mbr. overlays the late Eocene Bembridge Marls and dates from the very earliest Oligocene epoch, approximately 33.75 - 33.5 million years ago. To put the finds into an environmental context the Lower Hamstead Mbr. was deposited during a period of rapid global cooling and drop in sea levels associated with the onset of antarctic glaciation (Oi-1). The cooling and eustatic change had begun in the late Eocene, with the palaeo-environments of the Bembridge Marls becoming increasingly terrestrial towards the Eocene/Oligocene boundary. By the Lower Hamstead Member the southern Hampshire Basin was a low lying coastal plain with extensive wetlands, lakes, ponds and sluggish rivers flowing south east towards the early channel (at this time the channel was more a large embayment with only occasional connection to the North Sea). The dense sub-tropical forests of the late Eocene had disappeared and the landscape was dominated by open woodlands of pine, sequoia, and oak. The environment was much cooler and annual rainfall had significantly dropped since the Eocene, although temperatures would begin to rise again further into the rupelian and Hamstead Mbrs. The basin was surrounded by areas of chalk upland (still existing today) with forests of sequoia and broadleaf species. This dramatic climate change is likely what triggered the Grande Coupure, in which endemic Eocene mammals like the palaeotheres disappeared and were replaced with Asian groups such as carnivorans, rhinocerotids, anthracotheres, and a variety of other artiodactyls. The mammals of the dense tropical Eocene forests simply couldn't adapt fast enough to the new open environments of the Oligocene and ultimately failed to compete against the better adapted migrants. By the Upper Hamstead Member the mammals on the Hampshire Basin coastal plain are almost entirely of Asian origin. Therefore the micro-vertebrates lived in an environment of large scale climatic and ecological change, which I think adds another level of interest to collecting from this member of the Bouldnor Fm. The material I've collected so far is a lot more varied than the Bembridge Marls, but overall is less abundant. So far it's produced at least 3 fish taxa, 2 mammals, and an indeterminate piece of jaw which may be reptilian or mammal. 1. A skull element from a Bowfin (Amia sp.), these fish are very common in most horizons of the Bouldnor Fm. 2. A vertebra from a Bowfin (Amia sp.) 3. A damaged lateral scute from a Sturgeon (Acipenser sp.) showing the transition to a freshwater environment 4. An indeterminate piece of a tiny jaw, may be crocodilian although I'm not sure. 5. The nicest find of the lot, a lower incisor from the theridomyid rodent Isoptychus (ID'd by Jerry hooker from the NHM). These rodents looked similar to modern kangaroo rats, hopping along the ground on large rear legs. Bite marks on Isoptychus bones collected from Thorness Bay suggest that they were common prey for the bear-dog Cynodictis. 6. Finally 2 images of an unidentified mammal tooth. I'm unsure as to whether this is part of the tooth or the entire crown, but it doesn't appear to be from a rodent. Hope you all enjoyed the finds, Theo
  20. One of the problems I experience in studying microfossils is that of orienting a specimen so that crucial characters are visible. An example: for identification it is often necessary to check the shape of the tooth in the aperture of taxa in the family Hauerinidae. The tooth can be long or short, plain or bifid, present or missing, etc. The aperture is on the end of the test, so it isn't possible to look into it when the test is lying flat -- which it always does when the test is lying in a tray under the scope. Of course, it is possible to use a little glue on the opposite end and manipulate it into a vertical position: but this is a lot easier said than done! However, there is a much easier way to look at such things -- use a mechanical two-axis stage, which will allow you to turn a specimen to literally any position under the stereo 'scope. One of my holiday gifts this year was just such a stage, of the type most commonly used by entomologists to examine pinned insects. To use the stage, I have a size 0 insect pin from which I removed the head with side-cutter pliers. I put a small drop of gum tragacanth on the resulting blunt end of the pin, and touch it to the side of the specimen I wish to examine, where it quickly dries. I stick the sharp end of the pin into the soft rubber plug of the rotating arm of the stage, and I'm set to go. I can alter the orientation of the specimen by rotating either of the two axles of the stage; by rotating the whole stage around its vertical axis I get the third "axle". The pin is not too distracting, and only the little area under the glue is not visible. This works quite well! In this image, the aperture is at the upper end, toward the top. (Oops, mispelled "hauerinid", drat...) Two chambers are visible on this side, and there are three chambers visible on the opposite side. One can't see the tooth in the aperture, par for the course when the test is lying flat. Let's look at another specimen, mounted on the mechanical stage: I rotated this specimen by 90 degrees from its "flat" position, and now the aperture is perfectly placed for inspection. The long tooth in the aperture is clearly visible, as is the thickening of the lip. Another example using different orientations: here the specimen is perched on top of the pin. The genus Lenticulina is planispiral and involute, and the aperture is at the upper end of the exposed face of the final chamber. The aperture is radiate; i.e., composed of several thin slits in the shape of an asterisk. This can be difficult to see. In this image the position of the aperture is marked by the arrow, but the nature of the aperture is not at all clear. Rotating the test by 90 degrees to get a profile view gives us a better look, and this profile view is also most useful in species identification: In this image, the test is mounted on the pin, which is glued to the underside of the specimen. So why is the pin not visible? To light specimens under the 'scope I use a two-arm fiber optic illuminator -- careful adjustment of the twin light heads can "eliminate" the pin with shadows. (Any remaining reflections from the pin are easily removed with image processing software.) If the pin were visible, it would extend downward to the lower edge of the image. Eliminating the pin makes the specimen appear to "float in midair", but at the expense of a weakly illuminated underside. This image shows the involute structure nicely, the apertural face, the swollen center of the test, the thin peripheral keel, and the pale aperture area at the right end. The aperture itself is still not well revealed, however. Let's adjust the orientation a little more: Turning the right end of the test upward toward the objective lenses, and boosting the magnification a bit, brings the radiate aperture into better view. Three of the radial slits, filled with contrasting matrix, are fairly clearly shown. Further rotation upward toward the objectives would provide a fuller view of the aperture, but this view is sufficient to demonstrate that the aperture is indeed radiate in structure. This method of mounting a specimen on a pin is totally non-destructive: to remove the specimen from the pin one just immerses it in a drop of water, where the gum tragacanth will quickly dissolve, leaving the specimen completely undamaged. Hopefully this blog entry will encourage others to explore ways to alter the orientation of their specimens, whether for identification purposes or photo-imaging.
  21. Hi all, I think that this is my first time in this thread of the forum, after being active for about a year and a half... Shame on me! Well, just for your info I know absolutely NOTHING about microfossils. So please bear with me So I have a question for you guys: So I bought this microfossil slide recently for just 3,25€ (not sure if it’s a good deal or not, but seemed okay to me), thinking it would be useful to store my very small fossils. Well, when I got it, I had two surprises: 1) it’s a lot smaller than I thought it would be! Fossils can get REALLY small I guess! 2) there aren’t any walls or so separating each number square. I thought that this would be simply another one of these sorting boxes with different “sub boxes”, which are always useful for storing fossils appropriately; but then a mini version for microfossils. Seems like I was very wrong! So so my main question is: how do I use this? Also, if you have any tips on how to go around with microfossils appropriately o would be glad to hear them. Again, all this stuff is very new to me. Microfossils are definitely not my strong point. Thanks in advance, Max
  22. While picking specimens of Foraminifera from the Taylor Marl, of the Texas Cretaceous Gulfian Series, I found several fragments of a taxon that I could not recognize. However, today I found a nearly complete specimen of what is obviously the same organism. Frondicularia christneri Carsey, 1926 does not look much like a typical member of the genus. The overall shape of the test is fairly normal, but the sutures form a rather unusual pattern, and they are raised above the test surface and slightly thickened (limbate). The test is rimmed, and the sides are flat. (It is this rimmed edge which produces limbate sutures when additional chambers are added.) Note that the final chamber, bearing the terminal aperture, occupies the entire right edge of the test. (The lower left corner of the test has been broken away, which creates the obvious asymmetry.) This unusual structure is not unique within the genus, however; Michael's Foraminifera Gallery website shows at least one other taxon with the same type of limbate sutures. In his 1954 Handbook of Cretaceous Foraminifera of Texas, Frizzell transferred this species to the genus Kyphopyxa, a move that is neither cited nor recognized in the World Foraminifera Database. In her original description of the species, Carsey noted that it is more typical of the Austin Chalk, although not rare in the Taylor Marl. I have a sample of the Austin Chalk, and will be looking for this taxon when I get to it.
  23. Holiday greetings to all! This is just a notice that I'm reactivating my blog, Microfossil Mania!, with two new entries. More to come, mostly on the Texas Cretaceous and California Pleistocene and Miocene. Have a look if you are interested in forams and ostracodes. Rumi
  24. When I was preparing my previous entry on nodosariid forams from the Pecan Gap Chalk, I originally included a specimen that I had identified as a member of the genus Dentalina. This identification was incorrect, and I edited the entry to remove that specimen. Here it is again, with what I hope is the correct identification! The genus Strictocostella is a member of the family Stilostomellidae, and this species is illustrated in Frizzell's "Handbook of Cretaceous Foraminifera of Texas" as a member of the genus Stilostomella. He also listed it as occurring in the Pecan Gap Chalk. Better images can be found on the World Foraminifera Database -- they show specimens with some very small spines around the bases of each chamber, almost what one might call "hispid". The drawing in Frizzell does not show this feature, nor does my specimen. I have not yet looked at Cushman's original description, but I am reasonably confident that this difference is within the range of natural variation. (I have seen this kind of variation on images of other stilostomellids.) I like it when I "Live and Learn!" And I'm glad that I caught the error.............
  25. I have recently been studying a sample of washed residues from the Pecan Gap Chalk Formation of the Cretaceous Gulfian Series, from an outcrop in the vicinity of Austin, Texas. Most of the Gulfian formations are richly fossiliferous, and the Pecan Gap is no exception. It has abundant, well-preserved microfossils, particularly forams and ostracodes. In this blog entry I would like to show some forams of the family Nodosariidae, which I find of particular interest. All belong to the genus Frondicularia, which has compressed, biserial tests. Frondicularia archiaciana d'Orbigny, 1840 is one of the maddeningly similar "narrow" forms within the genus, whose identification often requires close attention to the contours of the test outline. The biserial growth form of the test appears in most members of the genus as inverted chevrons when the image is oriented with the aperture uppermost. This structure is more-or-less apparent depending on the relative transparency of the individual test, and it shows quite well in this image. What one is seeing are the suture lines between the chambers. The aperture in members of the Nodosariidae is radiate; this type of aperture does not stand up very well to post-depositional forces, and is very frequently broken away -- true of all four specimens in this entry. Frondicularia frankei Cushman, 1936 is one of a group of taxa within the genus in which the base of the test is not compressed. In profile, the base appears to be bulbous, with rather wide "ripples" oriented lengthwise. The upper 3/4 of the test is compressed, and appears quite flat in profile. The basal spine is one of the distinguishing characters of this species, although many others show such a spine also. Frondicularia intermittens Reuss, 1865 is another taxon of the "narrow" group, in which the chevrons produced by the biserial structure are less apparent. A few bright, length-wise streaks show that the sutures separating the chambers are depressed. The largest of the nodosariids that I have found thus far is Frondicularia mucronata Reuss, 1845. The larger, more ovoid appearance of this taxon is due in part to the greater length of the individual chambers, which also gives the "inverted chevron effect" a somewhat different character. The specific epithet is from the small basal tooth on the initial chamber (proloculus) of the test. Hopefully, readers have enjoyed looking at these little fossils. If so, stay tuned -- I'll be writing more about microfossils from the Texas Gulfian Series, and will also upload an entry on Pleistocene Ostracoda from the San Pedro Formation of California in the near future.