Return to the Jurassic Paradise of Makhtesh Gadol

April 15th, 2014

Makhtesh Gadol 041514MITZPE RAMON, ISRAEL–This week I’m back in Makhtesh Gadol, that great bowl of Jurassic delights. This is the most extensive exposure of marine Jurassic rocks in southern Israel, and it is highly fossiliferous. This is just a brief report. I’ll summarize the latest finds and ideas later.

Greened 608 041514Today I spent most my time sitting on these low outcrops at a place we affectionately call “GPS 004 C/W-608″. It is the most productive site for crinoids and their associated sclerobionts (organisms that lived on or in their skeletons, before or after death). There was something about the original distribution of these organisms, and then the preservation and landscape erosion, that makes this site so good. Today I was not disappointed.

MatmorCollectView070513Compare this view of the site in July last year with Oscar Mmari, Steph Bosch and Lizzie Reinthal (all Wooster seniors now). The winter and spring rains were a bit higher than normal in this part of the country, so the outcrop today looks positively overgrown! This picture makes me miss having my students along on this trip, but such are research leaves.

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.

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.

 

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.

Wooster’s Fossil of the Week: An infected crinoid from the Middle Jurassic of southern Israel

July 28th, 2013

CrinoidGalls03 copyThis weathered beauty is a stem fragment of the articulate crinoid Apiocrinites negevensis from the Matmor Formation (Middle Jurassic, Callovian) of the Negev, southern Israel. The regular divisions you see making up the stem are the columnals, which look a bit like a stack of poker chips. You can even make out the crenulations on the articulating faces of the columnals, seen as tiny zig-zags. What is unusual about this stem, of course, are the large swellings with multiple holes. These appear to be something like the galls you sometimes see in plant stems formed when a parasite is surrounded by living plant tissue.
CrinoidGalls02 copySenior Independent Studies student Lizzie Reinthal (’14) is working on these odd structures (we have dozens of examples) as part of her investigation of the taphonomy of A. negevensis in the Matmor Formation. We know that the swellings were made by the interaction of some sort of organism with the living crinoid, but we don’t yet know the timing or mechanism. It could be that the holes were drilled first into the stem and the crinoid grew the extra skeletal tissue to essentially push them away, or the swellings could have been the equivalent of galls and some sort of enclosed animal bored its way out of the structure. (And an extra point to those of you who spotted the barnacle boring! Note that it has no swelling around it and thus was likely drilled after the death of the crinoid.)

These infected crinoid stems were first described from the Matmor by Feldman and Brett (1998). They suggested they were from parasitic myzostome worms, which are usually found on crinoid arms and have a long fossil record (see Meyer and Ausich, 1983, and Hess, 2010). They could also be from some sort of embedded organism like that represented by Phosphannulus on Paleozoic crinoid stems (Welch, 1976).

Lizzie will be pursuing the mystery by careful sectioning some of these swellings and seeing if she can relate the crinoid skeletal growth patterns to either a borer or an embedded parasite. Unfortunately that means we must destroy some specimens to better understand the phenomenon, a classic dilemma paleontologists sometimes face.

References:

Feldman, H.R. and Brett, C.E. 1998. Epi- and endobiontic organisms on Late Jurassic crinoid columns from the Negev Desert, Israel: Implications for co-evolution. Lethaia 31: 57–71.

Hess, H. 2010. Myzostome deformation on arms of the Early Jurassic crinoid Balanocrinus gracilis (Charlesworth). Journal of Paleontology 84: 1031-1034.

Meyer, D.L. and Ausich, W.I. 1983. Biotic interactions among recent and fossil crinoids, p. 377–427. In: Tevesz, M.J.S. and McCall, P.L., eds., Biotic interactions in recent and fossil benthic communities. Plenum Press, New York.

Welch, J.R. 1976. Phosphannulus on Paleozoic crinoid stems. Journal of Paleontology 50: 218-225.

Wooster’s Fossils of the Week: Dinosaur footprints of unknown provenance

July 14th, 2013

DinosaurFootprintConcaveEpireliefThese are the only fossils in the Wooster collection I feel some shame about. They are tridactyl theropod dinosaur footprints. They are not spectacular, but they do the job for classes and visits by schoolchildren. I regret that we have them, frankly, because it means at some time in the distant past (well before me) someone chopped them out of a red sandstone, losing in the process all context including location and age. Footprints like these are most valuable, both scientifically and aesthetically, in their original places alongside the rest of the trackway. Now I can only guess that these footprints came from the Jurassic of the southwest, probably Arizona or Utah.

At least we can use them for some trace fossil terminology. (A trace fossil is evidence of organism behavior, such as a trail, burrow, boring or scratch marks.) The top image is what we expect from a fossil footprint: an indentation in the top of the sandy bed now turned to stone. It extends into the rock and is on the surface, so we call it a concave epirelief. (“Epi-” means surface.) The footprint below is also of a three-toed theropod dinosaur, but it extends out of the rock and is on the underside of the bed. We thus call it convex hyporelief. (“Hypo-” means underneath.)
DinosaurFootprintConvexHyporelief

WaterFilledFootprintOne quick way to see the outlines of an indistinct footprint is to fill a concave epirelief with water, as above. This provides much more contrast.
WilsonBoysFootprintThis is how dinosaur footprints should be appreciated: in the field as part of trackways. The kids above are three of my brothers a long, long time ago. I think this is near Tuba City, Arizona, and these are Jurassic theropod footprints like the Wooster specimens. Note that to increase contrast the footprint is filled with … let’s just say “water”.

References:

Miller, W.E., Britt, B.B. and Stadtman, K. 1989. Tridactyl tracks from the Moenave Formation of southwestern Utah (pp. 209-215). Gillette, D.D., and Lockley, M..G, eds., Dinosaur tracks and traces: Cambridge, Cambridge University Press.

Goodbye, Makhtesh Gadol (for now)

July 7th, 2013

GoodbyeMakhteshGadol070713MITZPE RAMON, ISRAEL–Today Team Israel 2013 had its last visit to Makhtesh Gadol, marking the end of Lizzie Reinthal’s and Steph Bosch’s fieldwork. We collected our last specimens from the Matmor Formation, which is exposed only in the center of this magnificent structure. The students above are looking down into the northern part of the makhtesh from the viewpoint at Mount Avnon.

MakhteshGadol070713This is a view from the same spot looking south along the western wall of the makhtesh. You can see a bit of the curvy, narrow road below that we used to enter and exit the makhtesh. This road was built by the British during World War II when they thought there might be oil underneath this breached anticline.

MG_BronzeAgeStructure070713This ring of stones is the remnant of a Bronze Age livestock pen, along with a probable small shelter for the shepherd in the lower left. This features are found throughout Makhtesh Gadol, usually up on the flanks of the walls or the Matmor Hills. I happened to come across this one in today’s walkabout.

LastCollecting070713Finally, here are students collecting at our last site — the southernmost exposure of the echinoderm-rich subunit we’ve found to be so productive. This morning we found … wait for it … two more bryozoans! This is usually not big news in most of the places I’ve worked, but it sure is here. They are again runner-types, but not Stomatopora. Much more to report on these after we get back home with them.

We still have five more working days in Israel. One will be devoted to finishing Oscar’s fieldwork, one to finishing smaller projects in the Makhtesh Ramon area, one to exploration of geological sites Yoav has chosen for us, one for a trip to Jerusalem and the headquarters of the Geological Survey of Israel, and a final day to make sure we’ve done all we came to do.

Next »