A Triassic afternoon in southern Israel

April 8th, 2014

Mitzpe Ramon distant view 040814MITZPE RAMON, ISRAEL–This afternoon I walked through the spectacular Middle Triassic sections in Wadi Gevanim on the southern side of the Makhtesh Ramon structure. I will be on a fantastic trip this Thursday to a little-visited Triassic section farther south, so I wanted to refresh my memory of these units. The above image is looking north from Wadi Gevanim to Mitzpe Ramon just visible on the cliff edge of the makhtesh. (What a setting, eh?)

Nautiloids Ammonites 040814I found myself almost completely repeating an entry from last year on Wadi Gevanim (which had the added bonus of students in it). Today I gathered some impressive fossil cephalopods from the Saharonim Formation (Middle Triassic, Anisian-Ladinian) for a group photograph. I note only now that one of the nautiloids above appears last year as well! From the upper left going clockwise: nautiloid, ammonite, nautiloid, ammonite. All are internal molds (the outer shell has been removed).

Nautiloid 040814That upper left nautiloid is worth a closer look. The mold has been split down the middle showing the septa (internal walls dividing the chambers) and an impressive “beaded” siphuncle (connecting tube) running the length of the conch (shell).

Terebratulids 040814Finally, here is a handful of the common terebratulid brachiopods from the Saharonim. Speaking of which, have I mentioned the species Menathyris wilsoni from the Saharonim? You certainly must meet Menathyris wilsoni!

A Wooster Geologist is finally warm enough

April 7th, 2014

Yoav Zichor 040714MITZPE RAMON, ISRAEL–When I left Wooster on Saturday morning it was 34°F and overcast. It was sunny and an astonishing 84°F when I arrived in Tel Aviv on Sunday afternoon. That additional 50 degrees felt very good indeed after a winter of polar vortices and late-March snowstorms. I’m now based in the Ramon Suites Hotel in Mitzpe Ramon near the lip of the spectacular Makhtesh Ramon (N 30.60638°, E 34.80128°).

I’m back in Israel as part of my research leave from the College. This is my chance to explore new outcrops and ideas with my Israeli colleagues to prepare for the next generation of Independent Study students — and, of course, to do plenty of science for its own sake. I miss my students, though, for their companionship, sharp eyes, challenging questions, and navigation abilities (i.e., telling me when I’ve taken a wrong turn). This is how the leave system works so that we always have fresh projects with interesting and testable hypotheses. This is my 11th field season in Israel.

Today I met my long-time friend Yoav Avni of the Geological Survey of Israel, along with Zeev Lewy, a paleontologist retired from the Survey, to look at a fossiliferous unit Zeev discovered over two decades ago south of Mitzpe Ramon. We looked at the thickest section of the Zichor Formation (Late Cretaceous, Coniacian) to sort out a remarkably diverse set of silicified (silica-replaced) fossils associated with a mat of worm tubes (possibly of the genus Filograna). The top image shows the upper portion of the Zichor, with Yoav for scale (location: N 30.30587°, E 34.96543°). The image below is a view of the bedding plane with most (but not all) of the silicified fossils colored dark brown.

Zichor silcified fossils 040714One of the cool things about this layer is that the fossils are silicified, which is rare in this part of the Cretaceous section. Another is that aragonitic mollusks are preserved in this way (especially gastropods and bivalves), along with their calcitic cousins (like oysters and pectenids). The Filograna-like worm tube layer itself is fascinating since no one knows much about the paleoecology of this group, and we suspect it may have some significant evidence about the paleoenvironment encoded in its spaghetti-like appearance.

Zichor Menuha contact 040714The top of the Zichor meets the bottom of the Menuha Formation chalks (Late Cretaceous, Santonian). In this view, the yellow and brown Zichor is in the foreground and middle ground, with the whitish Menuha in the background.

Zichor Menuha close 040714Yoav and I visited the boundary between the Zichor (darker unit on the left) and Menuha (lighter on the right) to assess their relationship (N 30.30212°, E 34.95909°). At outcrops 30 km to the north this boundary is marked by a deep unconformity (eroded interval) and a layer of encrusted and bored cobbles. Here the boundary is flat and nearly continuous. The layer of silicified shells is just a few centimeters below the unconformity. This may not be by chance — units immediately below unconformities often have silicified zones.

Some of you may remember these unit names from previous expeditions. Micah Risacher (’11) worked on the Zichor Formation and its fossils in the Makhtesh Ramon area, and Andrew Retzler (’11) did his Independent Study research on the Menuha. We can now build on their excellent work as we develop additional outcrops and new questions.

Ordnance 040714Finally, it wouldn’t be the Negev if there wasn’t some ordnance on the outcrop. Can you tell what kind of bomb is shown above? The clues are in its current condition!

Wooster Geologists at the North American Paleontological Convention in Florida

February 16th, 2014

Lizzie & Steph 021514GAINESVILLE, FLORIDA–Steph Bosch (’14), Lizzie Reinthal (’14) and I flew out of icy Ohio this weekend to attend the 10th North American Paleontological Convention in warm, sunny northern Florida. The students jointly presented the beautiful poster above on their Independent Study projects in the Matmor Formation (Middle Jurassic, Callovian) of southern Israel. It was very well received, especially with the addition of fantastic scanning electron microscope images of bryozoans produced by our colleague Paul Taylor at the Natural History Museum in London.

Crowd scene 021514Here’s a crowd scene from the first poster session at NAPC. If you look closely in the center, you’ll see two Wooster alumnae who are prominent paleontologists. Can’t swing a cat at a paleo meeting without hitting Wooster Geologists.

Hilton 021514This is a nondescript image of our hotel and convention center in Gainesville. I show it only to marvel in the blue, blue sky and perfect temperatures. We are on the University of Florida campus near the Florida Museum of Natural History. The paleontology staff at that museum is sponsoring this meeting — and they are doing an extraordinary job made more complex by the absence of about a third of the participants still snow-bound in the north. We escaped through a window of clear weather in Ohio.

Last official meeting of Wooster Team Israel

January 10th, 2014

Team Israel 2013 011014WOOSTER, OHIO — Above you see Wooster Team Israel 2013 veterans Lizzie Reinthal, Steph Bosch and Oscar Mmari (whom I seem to have caught with his mouth full). Since I’m starting a research leave this semester, we took a last chance to have an evening meeting with pizza, lemon dessert, popcorn and a movie in the warm Wilson living room. It is wintry Ohio outside, but we all have memories of the beautiful Negev:

GoodbyeMakhteshGadol070713a

And what was the movie? You really don’t need to ask, do you?

Lawrence poster

Wooster’s Fossil of the Week: A long scleractinian coral from the Middle Jurassic of Israel

November 17th, 2013

Enallhelia_370_Callovian_Israel_585Just one image for this week’s fossil, but we make up for the numbers in image length! The above fossil with the alternating “saw teeth” is the scleractinian coral Enallhelia d’Orbigny, 1849. It is a rare component of the diverse coral fauna found in the Matmor Formation (Callovian-Oxfordian) in southern Israel. I collected this particular specimen (from locality C/W-370 in Hamakhtesh Hagadol, for the record) during this past summer’s expedition to the Negev. It is preserved remarkably well considering that its original aragonite skeleton has been completely calcitized.

Enallhelia is in the Family Stylinidae, also named by French naturalist Alcide Charles Victor Marie Dessalines d’Orbigny. (Love that name; he was briefly profiled in a previous entry.) There are many species in the genus (at least two dozen), but I can’t figure out which this one is. I’ll need a coral expert because half of the available species look pretty much the same to me. Enallhelia is a dendroid coral, meaning its corallum has tree-like branches, only one of which we see here. Each branch has alternating corallites on each side, which in life would have held the individual tentacular polyps. Each corallite has radial symmetry, not the usual hexameral symmetry as seen in most scleractinians. The genus ranges from the Jurassic into the Cretaceous and is cosmopolitan. Enallhelia is especially well known from Europe, but that may be just a collector effect.

What I like about Enallhelia is that it can be an excellent paleoenvironmental marker. Leinfelder and Nose (1997) show that it is most often found in “marly coral meadows” near storm wavebase on carbonate platforms. This means it is in shallow but quiet waters well within the photic zone most of the time, but may be occasionally disturbed by storm wave currents. This is an accurate description of most of the depositional environment of the Matmor Formation.

References:

Hudson, R.G.S. 1958. The upper Jurassic faunas of southern Israel. Geological Magazine 95: 415-425.

Leinfelder, R.R. and Nose, M. 1997. Upper Jurassic coral communities within siliciclastic settings (Lusitanian Basin, Portugal): Implications for symbiotic and nutrient strategies. Proceedings of the 8th International Coral Reef Symposium 2: 1755-1760.

Olivier, N., Martin-Garin, B., Colombié, C., Cornée, J.-J., Giraud, F., Schnyder, J., Kabbachi, B. and Ezaidi, K. 2012. Ecological succession evidence in an Upper Jurassic coral reef system (Izwarn section, High Atlas, Morocco). Geobios 45: 555-572.

Wooster paleontologists present at the Geological Society of America meeting in Denver

October 28th, 2013

Lizzie102813DENVER, COLORADO–Yesterday Oscar Mmari (’14) gave the first presentation from Wooster’s Team Israel 2013 at the annual meeting of the Geological Society of America in Denver. Today our two paleontologists on the team discussed their posters.

Above is Lizzie Reinthal (’14) cheerfully giving her poster entitled: “Taphonomic feedback and facilitated succession in a Middle Jurassic shallow marine crinoid community (Matmor Formation, southern Israel)“. Her work is co-authored with our friend Howie Feldman. Below Steph Bosch (’14) is ready to discuss her work: “First bryozoan fauna described from the Jurassic tropics: Specimens from the Matmor Formation (Middle Jurassic, Upper Callovian) in southern Israel“. Steph’s poster has the famous palaeontologist Paul Taylor as a co-author.

Steph102813It is great fun to see these students make the transition, both intellectually and physically, from the scorched desert floor of the Negev to such a professional setting. The faculty are very proud.

 

First Wooster geology presentation at the 2013 annual meeting of the Geological Society of America in Denver, Colorado

October 27th, 2013

Oscar102713DENVER, COLORADO–It’s that time of year for geologists when we collect at one of two major national meetings. Wooster geologists are always well represented at the Geological Society of America convention, this year held in downtown Denver. Meagen Pollock, Shelley Judge and I are here with nine enthusiastic Wooster students. Some events have already taken place (notably for me the paleontology short course and an epic annual banquet meeting of the Paleontological Society), and we’ve had our first student poster presentation.

Oscar Mmari is shown above with his poster entitled: “Syndepositional faulting, shallowing and intraformational conglomerates in the Mishash Formation (Upper Cretaceous, Campanian) at Wadi Hawarim, southern Israel“. Readers of this blog will remember Oscar’s summer work in the Negev measuring and describing sections. Oscar’s presentation went very well. Every time I stopped by the poster someone was in deep conversation with him.

CCC102813Here’s an early morning view of the Colorado Convention Center in Denver where we’re doing our work and study (and socializing, truth be told). The weather this weekend has been fantastic, but a big change will come tomorrow morning.

More posts will follow!

Wooster’s Fossil of the Week: A nautiloid from the Middle Jurassic of southern Israel

September 8th, 2013

Cymatonautilus_AThis is the first nautiloid specimen I’ve seen in the Matmor Formation (Middle Jurassic, Callovian) after ten years of collecting in it. Our colleague Yoav Avni (Geological Survey of Israel) picked it up during this summer’s fieldwork. It is a beautiful internal mold in which the outer shell has been mostly removed, revealing the radiating lines where the internal walls (septa) intersected the outer shell. These intersections are called sutures. Here we see nice, simple sutures characteristic of nautiloids. Ammonites, on the other hand, can have very complex sutures indeed. Note that some of the outer shell still remains as an orangish layer recrystallized to calcite from the original aragonite. There are two round holes in the foreground. I’d like to think these are tooth marks from a predator, but there is not enough evidence to say that with any seriousness.
Cymatonautilus072913_BThis view of the outer edge of the top specimen shows a diagnostic feature of this particular genus: a deep sulcus (channel) running along the venter (periphery). Most nautiloids have a rounded venter, so this characteristic stands out.
Cymatonautilus072913_CThis is a side view of another specimen of the same nautiloid, also found by Yoav. The large hole at the center of coiling is called the umbilicus. It is especially large in this Matmor nautiloid. Note again the radiating sutures where the outer wall has been removed.

This nautiloid appears to belong to the genus Paracenoceras Spath 1927. I had to have this beaten into me by a half-dozen cephalopod workers. I thought it looked a lot like Cymatonautilus collignoni Tintant, 1969. If so, it would have been a new occurrence of this rare genus — the closest it has previously been found is in Saudi Arabia. Most importantly, it would have been a range extension for this genus. Previously it has been well documented as having appeared in a very short time interval: the latest early Callovian into the middle Callovian. In the Matmor Formation we found it in a bed in the upper Callovian, specifically subunit 52 in the Quenstedtoceras (Lamberticeras) lamberti Zone. Alas, my dreams of a paper describing this discovery was not to be. Another beautiful idea skewered by reality.

Paracenoceras was described by Leonard Frank Spath (1882-1957) in 1927. Spath was an interesting character. He was a British paleontologist who specialized in ammonites, but also delved into other cephalopods like our nautiloid genus here. He was a BSc graduate of Birkbeck College in 1912, eventually earning a doctorate at the same institution, now known as Birkbeck, University of London. He was a curator in the British Museum (Natural History) for most of his career. He was especially interested precise Jurassic and Cretaceous biostratigraphy using ammonites. He published more than 100 papers and monographs, was elected as a Fellow of the Royal Society, and received the Lyell Medal from the Geological Society of London in 1945. Spath was well known for his biting criticisms of German paleontologists, especially those who worked on ammonites. Turns out that he was keeping a secret from everyone, including his own children: his parents were German! His son (F.E. Spath) discovered this long after his death, publishing an account of his father in 1982. The elder Spath no doubt kept his German heritage secret for the obvious reasons, given his time and place.

References:

Branger, P. 2004. Middle Jurassic Nautiloidea from western France. Rivista Italiana di Paleontologia e Stratigrafia 110: 141-149.

Halder, K. 2000. Diversity and biogeographic distribution of Jurassic nautiloids of Kutch, India, during the fragmentation of Gondwana. Journal of African Earth Sciences 31: 175-185.

Halder, K. and Bardhan, S. 1996. The fleeting genus Cymatonautilus (Nautiloidea): new record from the Jurassic Charl Formation, Kutch, India. Canadian Journal of Earth Sciences 33: 1007-1010.

Kummel, B. 1956. Post-Triassic nautiloid genera. Bulletin of the Museum of Comparative Zoology 114(7): 320-494.

Spath, F.E. 1982. L.F. Spath (1882 – 1957), ammonitologist. Archives of Natural History 11: 103-105.

Tintant, H. 1969. Les “Nautiles à Côtes” du Jurassique. Annales de Paleontologie Invertébrés 55: 53-96.

Tintant, H. 1987. Les Nautiles du Jurassique d’Arabie Saoudite. Geobios 20: 67-159.

Tintant, H. and Kabamba, M. 1985. The role of the environment in the Nautilacea, p. 58-66. In: Bayer, U. and Seilacher, A. (eds.), Sedimentary and Evolutionary Cycles. Lecture Notes in Earth Sciences, vol. 1, Springer (Berlin).

Wooster’s Fossil of the Week: An almost planispiral gastropod from the Middle Jurassic of southern Israel

August 11th, 2013

 

Discohelix tunisiensis apical copyAdd this to the list of fossils that have confused me. This summer, during a Wooster expedition, Lizzie Reinthal and Steph Bosch collected the above specimen from the Matmor Formation (Middle Jurassic, Callovian) of southern Israel. I simply assumed it was an ammonite, especially because we were anxious to find ammonites to further reinforce our biostratigraphic framework (how we tell in which geological time interval our fossils belong). When I later tried to identify it by searching through the Jurassic ammonite literature, though, I could find nothing like it. I then sent a photograph to my friend Zeev Lewy, a prominent ammonite expert recently retired from the Geological Survey of Israel. His answer was a surprise: this fossil is the gastropod Discohelix tunisiensis Cox 1969.
Discohelix tunisiensis adapicalHow could this be a snail when it looks so much like a cool, multi-whorled planispiral ammonite, complete with ribs? Well, it is not planispiral, now that I look at it again. Above you see the other side of the specimen, with its slightly depressed center. Most ammonites don’t show such asymmetry. This actually is a gastropod, and it represents an ancient group (the clade Vetigastropoda — don’t get me started on the complications of gastropod systematics!) with primitive features reminiscent of Paleozoic marine snails (from a group I learned to call “archaeogastropods“). It is not as much that the snail has converged on an ammonite style of shell, it’s that the ammonites developed a similar shell much later for entirely different reasons (swimming, for example). Discohelix was likely an herbivore grazing in patchy coral reefs like we have represented in the Matmor Formation. It has become a useful index fossil for the Jurassic of the Tethyan Realm, although this is the first time I’ve found it in Israel.
Pseudotorinia (Architae-group) retiferaThe above is the marine snail Pseudotorinia (Architae-group) retifera. It used to be called Discohelix retifera, and you can see why. It may not be in the same genus, but you can see that this modern group and Discohelix are closely related. Discohelix itself is now known only from the fossil record.
DunkerDiscohelix was named as a genus in 1847 by Wilhelm Bernhard Rudolph Hadrian Dunker (1809-1885), a German natural scientist with interests in geology, paleontology and marine zoology. (I love that middle name of “Hadrian”.) Like so many 19th Century paleontologists, Dunker started with a practical training in mining engineering and then followed a passion for fossils and modern shells. He had a huge collection of materials that eventually ended up in the Museum für Naturkunde in Berlin. He traded and corresponded with many top scientists of his day, including Charles Darwin. He also published many monographs on modern and fossil molluscan taxa. In 1846, he and Hermann von Meyer established the journal Palaeontographica. This journal survives to this day in two descendants: Palaeontographica A (Paleozoology, Stratigraphy) and Palaeontographica B (Paleobotany).

References:

Cox, L.R. 1969. Gasteropodes Jurassiques du Sud-Est Tunisien [Jurassic gastropods from SE Tunisia]. Annales de Paleontologie, Invertebres 55: 241-268.

Grundel, J. 2005. The genus Discohelix Dunker, 1847 (Gastropoda) and on the content of the Discohelicidae Schroder, 1995. Neues Jahrbuch fur Geologie und Palaontologie-Monatshefte 12: 729-748.

Tëmkin, I., Glaubrecht, M. and Köhler, F. 2009. Wilhelm Dunker, his collection, and pteriid systematics. Malacologia 51: 39-79.

Wendt, J.1968. Discohelix (Archaeogastropoda, Euomphalacea) as an index fossil in the Tethyan Jurassic. Palaeontology 11: 554-575.

Wooster’s Fossil of the Week: An irregular echinoid from the Middle Jurassic of southern Israel

August 4th, 2013

Holectypus depressus adoral 585From the view above, this fossil from the Matmor Formation (Middle Jurassic, Callovian) of southern Israel looks like your standard echinoid (a group that contains sea urchins and sand dollars), but turn it on its side (see below) and you see it is unusual. Echinoids have two large categories: those that are globular in shape (like sea urchins) are called “regular“, and those that are flattened (like sand dollars) are “irregular“. (I know, oddly value-laden terms, these.) This specimen belongs to a group that is rounded on its top portion and flattened on its bottom (oral) surface. This between-ness makes it a fun little specimen.
Holectypus depressus Side 585I could not identify this echinoid, which we collected on our Israel expedition this summer, because I could not find the most important diagnostic features. Fortunately my colleague Andrew Smith, recently retired from the Natural History Museum in London, quickly knew what it was. (This is not surprising — he’s the world’s expert on fossil echinoids. Check out his incredible Echinoid Directory.) Andrew identified this specimen as belonging to the genus Holectypus Desor, 1842, and probably the species Holectypus depressus (Leske, 1778).
Holectypus depressus apical system 585The first feature Andrew noticed was the apical disk on the very top of the test (the term for an echinoid skeleton). In the above image (where the black scale bar = 200 microns) I’ve labelled the four gonopores (where gametes exit, as you might have guessed) and the madreporite (a sieve plate at the opening of the water vascular system). This arrangement is characteristic of the genus.
Holectypus depressus oral 585Most surprising to me was Andrew’s identification of the most obvious defining feature of Holectypus, the periproct (the anal opening). I couldn’t find it, but Andrew knew where to look. In this view of the oral surface, it is the gap labeled “P”. Looks just like a place where the test is broken, right?
Callovian France HolectypusHere is the oral surface of an unbroken Holectypus specimen from the Callovian of France. The large periproct is immediately visible as the whole at the bottom. Now the broken margin of the periproct on our specimen makes sense.

Holectypus belongs to a group of irregular echinoids still around today. They are sometimes characterized as having “conservative” evolution, meaning they have not changed much over long periods. The irregular echinoids appeared earlier in the Jurassic as a modification of their regular ancestors. They became flattened and bilateral, the periproct moved out of the apical disk, their ambulacra (rows of tube feet visible as tiny holes radiating from the apical disk on the top image) pulled up away from the mouth, and their spines were reduced in size and increased in number. These were primarily adaptations for burrowing into the sediment. Holectypus has retained its inflated upper portion, has relatively large spines (some still cling to our specimen), and still is circular in outline. It was a deposit feeder but not specialized for burrowing.

We wouldn’t want to call this a “transitional fossil”, but it is a nice example of the gradient of adaptations present when there is a major outbreak of innovation as during the rise of the irregular echinoids in the Jurassic.

References:

Kroh, A. and Smith, A.B. 2010. The phylogeny and classification of post-Palaeozoic echinoids. Journal of Systematic Palaeontology 8: 147-212.

Rose, E.P.F. and Olver, J.B.S. 1985. Slow evolution in the Holectypidae, a family of primitive irregular echinoids, p. 81-89. In: Keegan, B.F. and O’Connor, B.D.S. (eds.), Proceedings of the Fifth International Echinoderm Conference, Galway, 24-29 September, 1984.

Saucède, T., Mooi, R. and David, B. 2007. Phylogeny and origin of Jurassic irregular echinoids (Echinodermata: Echinoidea). Geological Magazine 144: 333-359.

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