Mark Wilson December 12th, 2014
We are pleased to introduce to the world four new species of Jurassic cyclostome bryozoans. In a paper that has just appeared in the Bulletin of Geosciences, Steph Bosch (’14), Paul Taylor and I describe the first tropical Jurassic bryozoan fauna (see Wilson et al., 2015, below; it is open access and a free download). This work was the basis of Steph’s excellent Senior Independent Study thesis, and it could not have been done without Paul’s bryozoan mastery and his scanning electron microscopy skills. We found six bryozoan species in the Matmor Formation (Middle Jurassic, Callovian) exposed in Hamakhtesh Hagadol, southern Israel, four of which are new to science and shown in this post. The image above is a colony of Hyporosopora nana n. sp. attached to a crinoid ossicle.
Identifying and classifying Jurassic cyclostome bryozoans almost always involves finding the specialized reproductive gonozooids. Here we see a close-up of the gonozooid on H. nana. The ooeciopore (an opening for communication with the water outside) is at the distal end on the right. The species name “nana” means “small” in Latin and refers to the small size of the autozooids (feeding zooids).
This is Hyporosopora negevensis n. sp., named after its type location in the Negev. On the right side of the colony you can see its characteristic boomerang-shaped gonozooid.
Idmonea snehi n. sp. is named after my good friend and superb geologist Amihai Sneh of the Geological Survey of Israel. Amihai has now “retired” officially after a distinguished career, but continues to work. He is the lead author of the new Geological Map of Israel. Turns out I have no images of him with his face to the camera.
This is a color optical image of I. snehi to show what these fossils look like outside the SEM. The wiggly lines you see in the background are where the host crinoid columnals articulate in the stem. (The crinoid is Apiocrinites negevensis.) I. snehi has the earliest example of lateral branching in a post-Paleozoic cyclostome, and is now the only published example of lateral branching in any Jurassic bryozoan.
Microeciella yoavi n. sp. (above) has a gonozooid with a spherical brood chamber, visible near the center of the image. It is named after another good friend and colleague, Yoav Avni of the Geological Survey of Israel. Yoav has been my field companion for over a decade now and is most responsible for the logistical and scientific success of our expeditions into the Negev. Yoav even accompanied the Wooster Geologists on our last departmental field trip to the Mojave Desert.
Team Israel 2013 worked hard to find the bulk of the bryozoans used in this study. They are shown above at one of our most productive sites in Hamakhtesh Hagadol.
We took a group photo in Jerusalem in July 2013. On the left is Steph Bosch (’14; bryozoan expert); next to her is Lizzie Reinthal (’14; crinoid specialist); then Oscar Mmari (’14; he worked on Cretaceous phosphates but also valiantly collected Jurassic bryozoans); then me; and on the far right Yoav Avni.
Please download and read the paper for more information and context on this study. The Matmor bryozoans are most similar to their counterparts in the Callovian of Poland. The low diversity of the Matmor bryozoan fauna is not unusual for the Jurassic, but they are less abundant than contemporaneous bryozoan faunas from higher paleolatitudes in Europe and North America. The unusually small zooids of the Matmor bryozoans may be a function of the “temperature-size rule” because this fauna developed in shallow, warm, tropical waters.
Ausich, W.I. and Wilson, M.A. 2012. New Tethyan Apiocrinitidae (Crinoidea, Articulata) from the Jurassic of Israel. Journal of Paleontology 86: 1051–1055.
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.
Wilson, M.A., Bosch, S. and Taylor, P.D. 2015. Middle Jurassic (Callovian) cyclostome bryozoans from the Tethyan tropics (Matmor Formation, southern Israel). Bulletin of Geosciences 90: 51–63.
Wilson, M.A., Reinthal, E.A. and Ausich, W.I. 2014. Parasitism of a new apiocrinitid crinoid species from the Middle Jurassic (Callovian) of southern Israel. Journal of Paleontology 88: 1212-1221.
Zatoń, M. and Taylor, P.D. 2009. Middle Jurassic cyclostome bryozoans from the Polish Jura. Acta Palaeontologica Polonica 54: 267–288.