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I am right now out in the field, attempting to extract a string of articulated reptile vertebrae in the lower Atco. It is in a soft marl bed just a few feet above the basal Atco. There seems to be articulated ribs associated with the specimen, and so far I have uncovered 14 verts. 9 of them were lose of the surface and bagged in ziplocks, but now I am trying to get the rest out. If anyone has any advice, I need it! The specimen also has articulated ribs. I want to get this thing home tonight, and not destroyed. This is is my first time attempting to extract vertebrae, and I want to do it right and get it home tonight. It is currently 8:54 p.m. here in North Texas. Here are some pictures of the bones when I found them and where the dig is now. I don’t know what exactly it is, but I am guessing juvenile Mosasaur. Age is Earliest Coniacian. 9 verts were on the surface, and at least 6 more uncovered with ribs. Pictures incoming: All 9 verts. @Uncle Siphuncle @erose
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Hey y'all! I am a geology/paleontology student at Texas A&M and I am researching the Austin Chalk. I was wondering if anyone had any good Austin localities near the Waco/Temple area or anywhere near 35 all the way up to Dallas. I’ve researched a few old papers and found a couple of spots but I figured this forum could be a good outcrop resource as well. Would love some help! Thanks so much.
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I recently purchased this vertebrae which was sold as a mosasaur (Clidastes) vertebrae. I wasn't convinced that the vert was Mosasaur (or even marine reptile for that matter) in origin when I bought it, I simply bought it because I thought it was a nice looking vertebrae. But now I thought I might give it a shot to try and get an ID on this thing. It was found in the Gober Chalk, Austin Group, Gober, Fannin County, Texas, USA and dates back to the Campanian, Cretaceous (± 80 mya). I don't really know what the vertebrae could be honestly, I don't believe it to be Mosasaur in origin or any other marine reptile like Plesiosaurs or Pliosaurs. I have been searching to see if it might belong to a cretaceous giant sea turtle like Archelon or something but I can't find really find any pictures of sea turtle verts to compare with. When I posted the vertebrae in my collection topic some members were inclined to point toward the vertebrae being mammalian in origin, but due to the size that would mean it probably isn't cretaceous in origin due to it's large size. So I made some more photos to get a better image of the vertebrae, I made some close ups a well of the bone structure and of the some of the places where you can clearly see remains of a chalk like matrix stucking to the bone. So I was hoping if someone might be able to put an ID on this thing and maybe if it is mammalian in origin where it might originate from should it not be cretaceous. Thank you in advance!
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In June of 2018, Kieth Minor alerted me to a new apartment complex that was being developed in the middle Atco Formation of North Texas. They were cutting a huge cubic area of rock out of a hillside, piling up multiple large mounds of Atco which seemed to be begging for someone to carefully search out their freshly exposed contents. On the 15th of that month we got to the site, Kieth asked permission of the site foreman for us to carefully take a look around during the crew's work hours, and we made our way into the pit. We were on a mission to save as many ammonites as we could. FIG 1: First impressions.
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Excerpt from W. J. Kennedy (1984): " Family NOSTOCERATIDAE Hyatt, 1894 [Jouaniceratidae Wright, 1952, p. 218; Bostrychoceratinae Spath, 1953, p. 16; Emperoceratinae Spath, 1953, p. 17; Hyphantoceratinae Spath, 1953, p. 16] Genus TRIDENTICERAS Wiedmann, 1962 Type species. Turrilites tridens Schlüter, 1876, p. 136, pl. 35, fig. 9; pl. 36, fig. 1; by original designation. Diagnosis. Turricone, ornamented by strong, flared ribs with three rows of tubercles, the lower two close together, and with non-tuberculate finer ribs between. Discussion. Schlüter figured only one specimen of his T. tridens, but Wiedmann (1962, p. 193, pl. 11, figs. 3, 7) has illustrated two views of a Spanish specimen agreeing closely with the original. To this can be added a specimen from the Coniacian of Terradillos de Sedano, Burgos, Spain, in the Oxford University Museum Collection (no. KZ14152) and two specimens from the Coniacian of Zûazû Navarra, Spain, Kindly loaned by Dr. G. Ernst of Braunschweig (casts are OUM KZ19173-19174). These show convincingly that, rather than being a survivor of the Turrilitidae which are otherwise restricted to the Albian and Cenomanian, Tridenticeras is a recoiled nostoceratid. It is suggested that the origin of the genus lies in Hyphantoceras Hyatt, 1900 or an allied genus. Turonian species of Hyphantoceras have a loosely and irregularly coiled spire and a recurved body chamber. Ornament of the spire consists of flared ribs with up to four rows of tubercles, with finer, non-tuberculate ribs between. Evolution simply involved recoiling, a trend widely shown by other heteromorphs. Weidmann also referred Turrilites peramplus Lasswitz (1904, p. 14, pl. 14, fig. 1) to the genus, while it is here suggested that T. varians Schlüter, 1876 (p. 137, pl. 35, figs. 11-13; pl. 36, figs. 2-5) is a further representative. This species has early whorls ornamented by fine, non-tuberculate ribs and periodic stronger trituberculate ribs, and a body whorl with flared, feebly tuberculate ribs and weaker non-tuberculate ribs between. This change in ornament matches that shown on adult H. reussianum (d'Orbigny, 1850), while the disparate sizes of the two adult specimens of Tridenticeras varians illustrated by Schlüter indicate dimorphism in the genus. Occurrence. Coniacian of Germany, France, northern Spain, and Texas, U.S.A." Personal notes: More information on the genus Tridenticeras can be found here and here. REFERENCES Wiedmann, J. (1962). Die Gabbioceratinae Breistroffer (Notizen zur Systematik der Kreideammoniten II.). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, Bd. 115, p. 1–43. Ulrich Kaplan und William James Kennedy (1994). Ammoniten des westfälischen Coniac. Geologie und Paläontologie in Westfalen, Heft 31, 155 S. Zdenek Vašíček (1990). Coniacian ammonites from Štíty in Moravia (Czechoslovakia). Sbornik geologickych ved, Paleontologie 32, Pages 163-195. W. J. Kennedy (1984). Systematic Paleontology and Stratigraphic Distribution of the Ammonite Faunas of the French Coniacian. Palaeontological Association, London, Special Papers in Palaeontology, No. 31. Barbra L. Emerson, John H. Emerson, Rosemary E. Akers and Thomas J. Akers (1994). Texas Cretaceous Ammonites and Nautiloids. Paleontology Section, Houston Gem and Mineral Society, Texas Paleontology Series Publication No. 5, 438 pp.
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From the album: Fauna and Flora of the Austin Group in Texas
This Tridenticeras peramplum specimen is 2.9 cm in height, and 1.9 cm in diameter. It shows the typical three rows of tubercles on each oblique rib, except on the most mature, bottom whorl. What I can tell from my references is that this is because only the phragmocone has tubercles, and thus the bottom whorl is the living chamber. -
From the album: Fauna and Flora of the Austin Group in Texas
This specimen is the largest of its genus in my collection, and the largest known to me in any collection. It measures about 7 cm in height, and 4.3 cm in diameter. It retains its tubercles in the most mature whorl sections that are preserved well enough to tell. The specimen is quite crushed. -
From the album: Fauna and Flora of the Austin Group in Texas
This specimen is the largest of its genus in my collection, and the largest known to me in any collection. It measures about 7 cm in height, and 4.3 cm in diameter. It retains its tubercles in the most mature whorl sections that are preserved well enough to tell. The specimen is quite crushed. -
From the album: Fauna and Flora of the Austin Group in Texas
This specimen is the largest of its genus in my collection, and the largest known to me in any collection. It measures about 7 cm in height, and 4.3 cm in diameter. It retains its tubercles in the most mature whorl sections that are preserved well enough to tell. The specimen is quite crushed. -
From the album: Fauna and Flora of the Austin Group in Texas
This specimen is the largest of its genus in my collection, and the largest known to me in any collection. It measures about 7 cm in height, and 4.3 cm in diameter. It retains its tubercles in the most mature whorl sections that are preserved well enough to tell. The specimen is quite crushed. -
From the album: Fauna and Flora of the Austin Group in Texas
This specimen is the largest of its genus in my collection, and the largest known to me in any collection. It measures about 7 cm in height, and 4.3 cm in diameter. It retains its tubercles in the most mature whorl sections that are preserved well enough to tell. The specimen is quite crushed. -
From the album: Fauna and Flora of the Austin Group in Texas
This specimen is the largest of its genus in my collection, and the largest known to me in any collection. It measures about 7 cm in height, and 4.3 cm in diameter. It retains its tubercles in the most mature whorl sections that are preserved well enough to tell. -
I found this Phlycticrioceras trinodosum heteromorph specimen in June of 2018 whilst hunting the middle/upper Coniacian Atco formation. It is the largest fragment of this species that I am aware of, having a whorl height of 51 mm as opposed to 47 mm of the largest fragment I've seen published. This genus is a bigger, rarer, and (mostly) younger cousin of Allocrioceras. I sent pictures of it to Keith Minor and he pointed out that there was also an echinoid sticking out of the specimen, something which I had totally missed! With much of the echinoid still stuck in the living chamber it is hard to get a definitive ID. But because it has such a shallow anterior ambulacra, which gives the anterior end a more smooth rather than definitive heart shape, he ruled out both Mecaster texanus and batensis. He suggested Micraster since the site has a strong European component in both the bivalve and ammonite faunas, and because the periproct side has the right shape. From finding other, although not as well preserved specimens that show similar morphology he appears to be right. I have yet to confirm this ID with Andrew Smith, but either way I think the piece is worth showing. And reading this thread got me thinking about how this could have happened and what effect it could have had on the echinoid's preservation. My thought is that because irregular echinoids lived and today still live most of their lives burrowing in the sediment it is unlikely that it would have crawled into the living chamber, but instead that it was blown into it post-mortem via currents that had dredged it out of the sediment. I already know that this site was a high energy environment from my other finds here so this seems the most likely possibility to me. But because of the fact there is still at least one spine still attached to the specimen it could not have been swept up from the sediment too long after death or all of its hairlike spines would have blown away. I do, however, find it interesting that it is positioned anterior first with its posterior towards the aperture, the position I would expect to see it in if it had indeed crawled into the shell. The specimen is also the best preserved echinoid from this site so far. Despite the ammonites being generally well preserved and not too crushed, most of the echinoids that I have from the site are terribly crushed, flakey, and often infested with rotting pyrite. I think being encapsulated in the chamber very much reduced those effects. Even though the ammonite and the echinoid are a bit crushed, the echinoid would have probably been worse off otherwise. The heteromorph fragment length is 70 mm and the whorl breadth, being a bit crushed, is 13 mm. I would think that this specimen, with its open planispiral coiling, would would have been at least over a foot in diameter when complete. It is the robust (female) morph of the species with a rib index of 5½. For comparison in Fig. 1 I pictured it with my most complete P. trinodosum specimen. From the part of the echinoid that is exposed I can measure 25 mm in length, 25 in width, and a thickness of 8 mm. I have also found abundant yet scattered fish remains at the site, so perhaps one day an ammonite-fish will come my way. But until then, anyone else got ammonite-echinoids to show? Fig. 1. Fig. 2.
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This heteromorphic species is characterized by an open plain spiral shape with slightly rursiradiate ribs and 3 sets of tubercles; 2 sets of ventrolateral tubercles, and 1 set of ventral tubercles. The whorl section is compressed and does not have constrictions in United States specimens but does have constrictions in many European specimens. The distance between ribs is roughly the same as the width of a rib. As far as I know, there are only two species reported for this genus, with the other being Phlycticrioceras rude from the late Santonian of France (Kennedy 1995). P. trinodosum is the only species reported in Texas. This species shows two morphotypes, with the more commonly found robust from having a lower rib index and the less commonly found gracile form having a higher rib index. This dimorphism is likely sexual, with the robust form being female and the gracile form being male. This particular specimen is a robust form with a rib index of roughly 3 1/2, but some gracile specimens of this species exhibit a rib index of up to 8 (Emerson 1994). The highest rib index of a P. trinodosum specimen that I have found is 7, this being on a fragment of a very mature gracile specimen. That specimen (seen here) shows very weak ventrolateral tubercles, a trait shared with all the other gracile specimens that I have seen thus far. This is in contrast to the strong ventrolateral tubercles of the robust form. It was broken in two when it separated from the rock shown in the last photo, with its outer whorl being shown in the 4th and 5th photos. The outer whorl is 53mm long, and at the top where the whorl height is measurable, it is 16mm. You can see in the photos of the main part of the specimen, the impression of where its outer whorl once was. The complete specimen would be about 65-70mm in diameter if its outer whorl was still connected. When applicable and needed, I have put the relevant pages for information, plates, and text figures at the end of references: Ulrich Kaplan und William James Kennedy (1994). Ammoniten des westfälischen Coniac. Geologie und Paläontologie in Westfalen, Heft 31, 155 S. Pages 53, 54; Tafel 37, Figures 2-4, 9-15 on pages 142, 143; Tafel 43, Figure 3 on pages 154, 155. Zdenek Vašíček (1990). Coniacian ammonites from Štíty in Moravia (Czechoslovakia). Sbornik geologickych ved, Paleontologie 32, Pages 163-195. Pages 177, 179; Plate VI with its explanation is on page 193. Young, K. (1963). Upper Cretaceous Ammonites from the Gulf Coast of the United States. University of Texas, Publication 6304, 373 pp. Pages 45, iv, 39, 47, 371; P. sp. cfr. douvillei on pages 45, iv, 23, 26, 29, 371; Plate 4, figures 2, 3 on pages 150, 151; Plate 11, figure 2 on pages 168, 169; text figure 7 f, h on pages 156, 157. W. J. Kennedy (1984). Systematic Paleontology and Stratigraphic Distribution of the Ammonite Faunas of the French Coniacian. Palaeontological Association, London, Special Papers in Palaeontology, No. 31. Pages 136, 137; Plate 32, figures 4, 11 on pages 140, 141; text figure 42E on pages 146, 147. David L. Clark (1963). The Heteromorph Phlycticrioceras in the Texas Cretaceous. Journal of Paleontology, Vol. 37, No. 2, pp. 429-432. W. J. Kennedy, M. Bilotte and P. Melchior (1995). Ammonite faunas, biostratigraphy and sequence stratigraphy of the Coniacian-Santonian of the Corbieres (NE Pyrenees). Additional links to information concerning this paper can be found here and with the species Phlycticrioceras rude, listed here. Kennedy, W.J. and Cobban (1991). Coniacian Ammonite Faunas from the United States Western Interior. Palaeontological Association, London, Special Papers in Palaeontology, No. 45, 96pp. Barbra L. Emerson, John H. Emerson, Rosemary E. Akers and Thomas J. Akers (1994). Texas Cretaceous Ammonites and Nautiloids. Paleontology Section, Houston Gem and Mineral Society, Texas Paleontology Series Publication No. 5, 438 pp. Pages 285, 286, 388, 422. Ulrich Andrew S. Gale, William James Kennedy, Jackie A. Lees, Maria Rose Petrizzo and Ireneusz Walaszczyk (2007). An integrated study (inoceramid bivalves, ammonites, calcareous nannofossils, planktonic foraminifera, stable carbon isotopes) of the Ten Mile Creek section, Lancaster, Dallas County, north Texas, a candidate Global boundary Stratotype Section and Point for the base of the Santonian Stage. Acta Geologica Polonica, Vol. 57, No. 2, pp. 113-160. The 1st, 2nd, 4th and 8th papers also contain information on Tridenticeras, another heteromorphic genus found in the Austin Chalk alongside P. trinodosum. A big thanks to DPS Ammonite. This is my first post to 'Collections' and he helped me get it all straight.
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