New Title Banner!!

After a few years, I thought it was fair to change the look of the blog a little bit. If you look up I've changed the banner, to one thats better (I think) and less crowded than the previous one. The pictures on the new title banner are all from different localities I've been doing fieldwork over the last couple of years and expect to continue to do so.

As for the old one, here's what was in it.

1) Pleistocene beach deposits in Isabela, Puerto Rico

2) Illustration of the skull of a new dugongid taxon (more on this in 2014)

3) Portunid crab from the San Sebastian Formation

4) Cross-bedded sandstones of the San Sebastian Formation

5) Tooth of Physogaleus contortus from the Lares Limestone

6) Tooth of Hemipristis serra from the Juana Diaz Formation

7) Outcrop of the Lares Limestone along road 111 in San Sebastian, Puerto Rico

8) Illustration of the skull of Dugong dug on showing the muscle attachment sites, modified from Domning (1977)

9) Mandible of Nesophontes edithae, one of several extinct Pleistocene mammals from PR 

Of course, feel free to guess where the pictures in the new banner were taken and leave your comments below. Good luck!!

Back to the western Caribbean, Pt. 1

Its been quite a while since the last post here at Caribbean Paleobiology. Lots of traveling and working hard on publishing parts of my dissertation as well as my current research projects here in Panama (stay tuned for more on this next year) have kept me extremely busy.

As I have mentioned previously, my work during this postdoc requires that I lead a group of interns (you can learn more about the internship here) as we search for terrestrial vertebrates in early Miocene deposits exposed on the Pacific side of the Panama Canal (see previous post). However, every now and then, as you may have seen in previous posts (here and here), we get to go to the Caribbean side of Panama in search of late Miocene marine vertebrates in the Chagres Formation. This is the first part of a series about our recent efforts to collect fossil marine vertebrates and to better understand the geology of the Chagres Fm.

Map of the northern part of the Panama Canal Basin. Here you can see the extension of the Chagres Formation and its members (map from Collins et al., 1996). (Click on the image to see a larger version.)

The Chagres Formation
This formation, exposed on the northern part of the Panama Canal Basin (see map above), generally consist of three distinct members or facies: Toro Member, silty sandstone facies, and Rio Indio facies (Collins et al., 1996). Age estimates for the deposition of the Chagres have been made using Foraminifera (which are extremely good index fossils). As a result, we known that the formation was deposited between 8.6-5.6 million years ago (Collins et al., 1996), during the final part of a geologic period known as the Miocene.

Toro Point, located southwest of the Caribbean exit of the Panama Canal, located within Ft. Sherman, which is a former US military base.

The Toro Member is the basal unit of the formation, and consist of cross-bedded coquinas and medium to coarse sands (see picture below). Coquina, is a term used to describe a sedimentary deposit that consists mostly, if not entirely, of shell fragments. In the case of the Toro Member, it is made up almost entirely of echinoid (sea urchin) and barnacle fragments, together with other less common bivalves and gastropods. Both, the types of invertebrates that make up the coquina, as well as the cross-bedding is indicative of high-energy, shallow marine habitats (Hendy, 2013)

Cross beds of the Toro Member, as exposed in Toro Point.

Disregarding what the geology and macroinvertebrates suggest, the Toro Member has been interpreted as being deposited at much deeper depths (several hundreds of meters), by a high-energy stream flowing from the Pacific Ocean towards the Caribbean sea, and thus representing the final connection between these two oceans (Collins et al., 1996). This interpretation, is based on the occurrence of deep-water fossils of Pacific affinities within the silty sandstone facies.

The silty sandstone facies of the Chagres Formation, as exposed in Playa Tortuguilla, located northeast of Fuerte San Lorenzo, and the mouth of the Chagres River. From left to right: James, Sarah, Elena and Zach (Fall 2013 interns) are studying the trace fossils of the Chagres. 

About 4-5 kilometers southwest of Toro Point, is where the main part of the Chagres Formation, the silty sandstone facies, is exposed. This is the most extensive of the members, going from southwest of Toro Point to about ~6 kilometers southwest of the village of Piña. Foraminifera (or forams for short) are not only used for estimating when marine units were deposited, but can also serve as index fossils for depositional depth, and environment. Forams collected from the silty sandstone facies of the Chagres were used for estimating the depth of this part of the formation, resulting in an estimate of somewhere between 200-500 meters (Collins et al., 1996).

Outcrop of the silty sandstone facies of the Chagres Formation near the village of Piña.

Forams are not the only fossils known from these units. Fierstine (1978) described a fossil marlin which he dubbed Makaira panamensis, an extinct species only known from this place and time. Other fossils found in these facies are fish otoliths. Otoliths are fish ear bones; they can be identified fairly accurately, and, similar to forams, they can be used as index fossils. A preliminary study of the otolith fauna of the silty sandstone facies collected near the village of Piña, suggests that these facies were deposited somewhere between 100-700 meters (De Gracia et al., 2012). This is a broader estimate, than that obtained using the forams, but still consistent with the idea that the silty sandstone facies represent relatively deep marine environments. These units, have so far, proven to be the most productive in terms of vertebrate fossils, thus most of our efforts have been in this area. In fact, back in 2011, I was near Piña, collecting a fossil dolphin* as part of the Pyenson Lab, and, more recently, with the Spring 2013 interns we collected a fossil sperm whale and parts of a marlin skull. (More about even more recent discoveries in the following iterations of this series).
*You can see more of the fossil dolphin collected during the Pyenson Lab 2011 expedition here!

Outcrop of the Río Indio facies of the Chagres Formation, somewhere south of La Boca del Indio. 

Towards the southwest, along the opposite site of the basin, between Palmas Bellas and Rio Gobea, is where we find the Rio Indio facies. These facies are characterized by siltstones and sandstones (Collins et al., 1996). Estimates of the depositional environment of these facies are variable, but generally much shallower than those of the silty sandstone facies (see below). Based on forams, it ranged from 50-80 meters, whereas estimates based on fish otoliths (= fish ear bones) it ranges from 0-100 meters (Collins, 1996; Collins et al., 1996; Aguilera and Aguilera, 1999). Just today was our first time visiting some of the Río Indio localities, and although we didn't find any vertebrates, we did find mollusks which are consistent with the shallower depth interpretations of previous workers.

So, stay tuned for the upcoming installments of this series!


Literature Cited

Aguilera, O., and D. R. de Aguilera. 1999. Bathymetric distribution of Miocene to Pleistocene Caribbean teleostean fishes from the coast of Panama and Costa Rica. Bulletins of American Paleontology 357:251-270.

Collins, L. S. 1996. Environmental changes in Caribbean shallow waters relative to the closing Tropical American Seaway; pp. 130-167, in J. B. Jackson, A. Budd, and A. Coates (eds.), Evolution and Environment in Tropical America. University of Chicago Press, Chicago, Illinois.

Collins, L. S., A. G. Coates, W. A. Berggren, M.-P. Aubry, and J. Zhang. 1996. The late Miocene Panama isthmian strait. Geology 24:687-690.

De Gracia, C., J. Carrillo-Briceño, W. Schwarzhans, and C. Jaramillo. 2012. An exceptional marine fossil fish assemblage reveals a highly productive deep-water environment in the Central American Seaway during the late Miocene. Geological Society of America Abstracts with Programs 44:164.

Fierstine, H. L. 1978. A new marlin, Makaira panamensis, from the late Miocene of Panama. Copeia 1978:1-11.

Hendy, A. J. W. 2013. Spatial and stratigraphic variation of marine paleoenvironments in the middle-upper Miocene Gatun Formation, Isthmus of Panama. Palaios 28:210-227.

Updates from Panama

Soon after the last post, I headed out to the US, for a short collection trip. During this trip, I visited both the Florida Museum of Natural History (FLMNH), and the National Museum of Natural History (NMNH) as I needed to compare my notes on some fossil cetaceans from the late Miocene of Panama with material housed in those institutions. It was also an opportunity to see my wife as well as spend some quality time with some good friends.

Gainesville, FL
At the Florida Museum of Natural History, I focused on comparing the Panamanian material with several fossil toothed whales in the collections, mainly from the late Miocene and early Pliocene of Florida. There are some interesting specimens at the FLMNH and I was able to make some useful comparisons. I also took some time to look at the exhibits in the museum, which I had not fully done yet.

Me, pointing out to the Florida dugongid triad, of which I wrote early last year (Vélez-Juarbe, et al., 2012). These are part of one of the exhibits at the Florida Museum of Natural History. Not everyday you get to see fossils you've worked on as part of an exhibit. One of those is a new species, so stay tuned!!

Washington, DC
At the Smithsonian in Washington, DC, I had the opportunity to look at both extant and fossil whales. For this, I went to the Smithsonian's Museum Support Center (MSC) which is where the extant whales are housed. If you study whales and dolphins of any kind, this is the place to go! The collection at the MSC allows us to look at more than one individual of a certain species, which gives us a better understanding of differences in the morphology due to age (juveniles vs adults) or sex (males vs females), or just variation within a species. We need to know this, specially when it comes to describing fossil species.

The "whale warehouse", one of the several storage facilities at the Smithsonian's Museum Support Center. If you need to look at skeletons of extant whales, this is the place to go!

The skull of Bohaskaia monodontoides a fossil beluga which Nick Pyenson and myself described last year (Vélez-Juarbe & Pyenson, 2012). Now part of a temporary exhibit called "Whales: From Bone to Book". Make sure you see it if you're in the DC area, its awesome!!

I also looked at several fossil whales, mostly physeteroids, which is the group that include sperm whales and pygmy sperm whales.

Some of the fossil whale I studied at the NMNH. Left: cast of the skull of Aulophyseter morricei, a small sperm whale from the middle Miocene of California (Kellogg, 1927). Right: the skull of Aprixokogia kelloggi, a fossil pygmy sperm whale from the early Pliocene of North Carolina (Whitmore & Kaltenbach, 2008).

Panama
After the US tour, I returned to Panama. Fieldwork so far, has been pretty standard along the canal. One of the recent highlights, was the visit of Bruce MacFadden, who brought a fantastic group of school teachers from California and Florida. We all did some fieldwork along the canal and also went to some localities of the Gatun Formation. At one of the Gatun localities the teachers had prepared an in situ paleontological workshop for a group of local schoolchildren, which was a wonderful experience for all of us involved!

The students were measuring diversity within a meter square grid.

It was not all fieldwork. We also had the chance to go birdwatching along the Pipeline trail in Gamboa, where we did get to see several birds, as well as a lot of other fauna along the trail.

On our hike along the Pipeline trail, led by George Angehr of the BioMuseo, and also author  of Birds of Panama (an excellent reference).

Some of the fauna we saw along the Pipeline trail. Clockwise from top left: leaf beetle (Platyphora haroldi); brown-throated three-toed sloth (Bradypus variegatus); black-tailed trogon (Trogon melanurus); striped rocket frog (Silverstonneia flotator).

So I guess that's it for now. But stay tuned as more discoveries are made in the canal and elsewhere here in Panama!


References
Kellogg, R. 1927. Study of the skull of a fossil sperm-whale from the Temblor Miocene of southern California. Carnegie Institution of Washington Publication 346:1-23.

Vélez-Juarbe, J., and N. D. Pyenson. 2012. Bohaskaia monodontoides, a new monodontid (Cetacea: Odontoceti: Delphinoidea) from the Pliocene of the Western North Atlantic Ocean. Journal of Vertebrate Paleontology 32:476-484.

Vélez-Juarbe, J., D. P. Domning, and N. D. Pyenson. 2012. Iterative evolution of sympatric seacow (Dugongidae, Sirenia) assemblages in the past ~26 million years. PLoS ONE 7(2):e31294.

Whitmore, F. C., Jr., and J. A. Kaltenbach. 2008. Neogene Cetacea of the Lee Creek Phosphate Mine, North Carolina; pp. 181-269 in C. E. Ray, D. J. Bohaska, I. A. Koretsky, L. W. Ward, and L. G. Barnes (eds.), Geology and Paleontology of the Lee Creek Mine, North Carolina, IV. Virginia Museum of Natural History Special Publication 14.

Whale Rescue in the Canal

A little more than a month ago I got an email regarding a fossil find near the construction site of the new canal locks on the Atlantic side of Panama. The photo that came with the email was a bit blurry and with no scale, so it could as well be a small fossil, or even an invertebrate. However, I took the chance as it was, after all, an opportunity to look at outcrops on that part of the canal (most of our work is towards the Pacific side). And so it was, that the spring interns (previously featured here and here) and myself ended up driving towards Colón with the hopes that the fossil was some sort of interesting vertebrate.

One thing I must mention, is that security is very tight in the canal, much more so near the construction sites. So that day, we only had about 20 minutes to look at the fossil and eventually come up with a plan to collect it at some later time, if it was worth it.

And it was! Upon seeing the fossil, I immediately recognized it as a baleen whale jaw. Most of what we could see was a cross section of it (see below), which meant that however long the jaw was, it was going straight into the wall.

Part of a baleen whale jaw, in cross section.

It is not the first time that fossil whales have been found in Panama. A 2010 paper by Mark Uhen of George Mason U. and colleagues (including yours truly) described all that was known of the fossil marine mammals of Panama. Admittedly, it wasn't much, but we were able to confirm the presence of dugongid sirenians, toothed whales (odontocetes) and baleen whales (mysticetes) (Uhen et al., 2010).   Since then, more and better material has been found, including a couple of odontocete skulls that I have helped collect from the late Miocene Chagres Formation (see here and here), as well as other things you'll hear about later this year at SVP.

The new whale mandible was found in the Gatun Formation of late Miocene (12-8 Ma) age (Collins et al., 1996). The Gatun is better known for the abundance of invertebrates (e.g. Woodring, 1957; Hendy, 2013) and for having deposits that represent nursery sites for Carcharocles megalodon (Pimiento et al., 2010). Previous reports of whales from the Gatun include odontocete ribs (Uhen et al., 2010), so finding a baleen whale is a first!

Like I mentioned above, that day we only had a very limited amount of time, and the fossil was worth rescuing. And so it was that over the next month or so I began coordinating with the Panama Canal Authority to go back and collect the fossil. Just last week we were able to go back. This time I had a new group of interns, and over the course of two days we were able to collect the fossil.

The summer interns at the dig site. Chris (at far left) prospects, while Christina and Silvia dig around the whale jaw.  You can see the construction of the new locks in the background.

Unfortunately, due to the nature of the outcrop we only had a limited space and depth to dig. So we had to make the best out of it. Sadly, that meant that if the jaw was longer than our depth limit, we had break it.

The whale jaw, prior to being jacketed.

Me posing with the now jacketed whale jaw fragment. 

The exact affinities of the whale jaw remain a mystery, for now. Hopefully once it is prepared I'll be able to determine what it is. So stay tuned!


References

Collins, L. S., A. G. Coates, W. A. Berggren, M.-P. Aubry, and J. Zhang. 1996. The late Miocene Panama isthmian strait. Geology 24:687-690.

Hendy, A. J. W. 2013. Spatial and stratigraphic variation of marine paleoenvironments in the middle-upper Miocene Gatun Formation, Isthmus of Panama. Palaios 28:210-227.

Pimiento, C., D. J. Ehret, B. J. MacFadden, and G. Hubbell. 2010. Ancient nursery area for the extinct giant shark Megalodon from the Miocene of Panama. PLoS ONE 5(5):e10552.

Uhen, M. D., A. G. Coates, C. A. Jaramillo, C. Montes, C. Pimiento, A. Rincón, N. Strong, and J. Velez-Juarbe. 2010. Marine mammals from the Miocene of Panama. Journal of South American Earth Sciences 30:167-175.

Woodring, W. P. 1957. Geology and paleontology of Canal Zone and adjoining parts of Panama. Geology and description of Tertiary mollusks (gastropods: Trochidae to Turritellidae). U.S. Geological Survey Professional Paper 306-A:1-146.

The Southernmost Atlantic Seacows

Its been a while since I posted news on fossil sirenians. I've been very busy with fieldwork, manuscripts, among other things. The Spring interns have now gone back home. So, while I wait for the arrival of the next round of interns, here's the latest on fossil sirenians.


Where are sirenians found

With the exception of the now extinct Steller's seacow (Hydrodamalis gigas), all extant sirenians have tropical to subtropical distribution, with some species having a notably broad latitudinal and longitudinal distribution (Marsh et al., 2011). But, when we look at the fossil record of sirenians, we see a slightly different pattern of distribution, mostly tied to tectonic and/or climatic events. For example, during parts of the Cenozoic global temperatures were higher than today (Zachos et al., 2001), so you find fossils of sirenians far off their modern range (e.g. Belgium). These climatic variations amongst other physical drivers have played a prominent role in the distribution of seagrasses and seacows (expect more on this in the nearby future).

Nowadays, in the Western Atlantic and Caribbean (WAC) region, the most common and widespread sirenian is the West Indian Manatee (Trichechus manatus) whose range extends from as far north as the Carolina's (with some individuals reaching New England) to northeastern Brazil; another species found in the region is the Amazonian manatee (Trichechus inunguis) which lives in the Amazon basin (see map below). But, it hasn't always been like this. Throughout most of the Cenozoic, dugongids, a group of sirenians are now restricted to the Indo-Pacific region, were the predominant seacow group in the WAC, including multispecies communities in the region (Domning, 2001; Velez-Juarbe et al., 2012a; see previous post on this subject). Fossil of dugongids in the WAC are found in deposits as far north as Maryland, and as far south as Argentina. However, these southernmost dugongids, are poorly known, and have had a somewhat rocky taxonomic history.


From Metaxytherium to Dioplotherium a case of mistaken identity

The most common, and temporally and geographically widespread seacow genus known is the Halitheriine dugongid Metaxytherium. Species of this genus are known from late Oligocene through Pliocene deposits, and are found from the Eastern Pacific, Caribbean, Western and Northern Atlantic, and Western Tethys regions (e.g. Domning, 1988; Sorbi et al., 2012). Therefore it shouldn't have been much of a surprise when Roy H. Reinhart (1976) described a molar from the late Miocene Paraná Formation of Entre Ríos, Argentina as that of Metaxytherium. The importance of this find, lies in that prior to its discovery, the youngest species of Metaxytherium known from the WAC was the middle Miocene M. floridanum, which is not known outside of Florida (Domning, 1988). The Paraná molar was then, the youngest and southernmost record of the genus from the Western Atlantic.

However, species of Metaxytherium display a generally conservative morphology, and because of this, it has had a long, somewhat convoluted, taxonomic history. This is, fortunately, slowly being resolved as most species of Metaxytherium have been re-described (e.g. Domning, 1988; Domning & Pervesler, 2001; Sorbi et al., 2012) and studied in detail within the last 25 years, giving us, paleosirenologist a better idea of the valid species within the genus and variation within each species. Since Reinhart's description, several workers (Cozzuol, 1996; Cione et al., 2000; Domning, 2001) have disagreed with his interpretation regarding the affinities of the Argentinian molar. All of them referring the Paraná molar to Dioplotherium, still a dugongid, but one that belongs to the Dugonginae, a group very different from that to which Metaxytherium belongs. And indeed, the overall morphology of the tooth conforms well with what we know about Dioplotherium, it is in fact, very similar to those of Dioplotherium cf. D. allisoni from the early Miocene of Brazil (Toledo & Domning, 1991). This meant that Metaxytherium may have gone extinct in the WAC at the end of the middle Miocene (Domning, 1988), and that the genus only reached as far south as northeastern Brazil (Toledo & Domning, 1991), or did it?

Left: Map showing the distribution of Miocene seacows throughout the Americas. (ER = Entre Ríos).
Right: Map showing the distribution of extant sirenian in the Americas.
(Click on the map to view larger version.)

New fossils from the Paraná Formation

A couple of years ago I received an email from an Argentinian colleague, Jorge Noriega from CONICET in Diamante, informing me of a new discovery from the Paraná Formation in Entre Ríos. The new fossils consisted of left and right partial maxillae and most of the molars of a single individual (see figure below). At this point I was close to finishing my PhD, which meant that I had look at a lot of specimens and was well acquainted with the morphology of most, if not all Oligocene through Pliocene sirenians. Once I looked at the pictures of the new material, I quickly recognize these as most likely representing a species of Metaxytherium.

Molars of Metaxytherium from the late Miocene Paraná Formation. 1-2) left maxilla and M1-3 in occlusal view. 3-4) right maxilla and M3 (modified from Velez-Juarbe et al., 2012b)

Now, I must admit that dugongid teeth are not the most diagnostic, so figuring out if these actually belonged to Metaxytherium was not an easy and quick task. After a considerable amount of reading, and detailed observations of material from various species of Metaxytherium as well as other dugongids I was confident they belonged to that genus. And so, working together with Jorge and Brenda Ferrero (also from CONICET in Diamante) we took on the task of formally re-designating the fossil described by Reinhart (1976) as well as describing the new material which actually represented a species of Metaxytherium (Velez-Juarbe et al., 2012b). The new Parana molars are quite similar to those of the middle Miocene Metaxytherium floridanum, but, their dimensions are below the range exhibited by M. floridanum and may represents a different species. One of the positive outcomes resulting from this work, was realizing that teeth of dugongids can sometimes be of taxonomic usefulness. We noticed, that the molars of some of the more derived species of Metaxytherium often have additional cusp and/or cuspules, a derived character which is not observed in Dioplotherium or any of its kin (i.e. Dugongines). The contemporaneous presence of both, Dioplotherium and Metaxytherium is not something unheard of. This same duet, occurs in the late Oligocene of Florida, early Miocene of Brazil and possibly in the middle Miocene of California and Baja California (Domning, 2001; Velez-Juarbe et al., 2012a). This again shows that multispecies communities and niche partitioning seems to have been the norm, not the exception, throughout sirenian history.


References

Cione, A. L., M. M. Azpelicueta, M. Bond, A. Carlini, J. Casciotta, M. A. Cozzuol, M. de la Fuente, Z. Gasparini, F. Goin, J. Noriega, G. Scilato-Yané, L. Soibelzon, E. Tonni, D. Verzi, and M. G. Vucetich. 2000. Miocene vertebrates from Entre Ríos Province, Argentina. INSUGEO, Serie Correlación Geológica 14:191-238.

Cozzuol, M. A. 1996. The record of the aquatic mammals in southern South America. Münchner Geowissenschaftliche Abhandlungen A30:321-342.

Domning, D. P. 1988. Fossil Sirenia of the West Atlantic and Caribbean region. I. Metaxytherium floridanum Hay, 1922. Journal of Vertebrate Paleontology 8:295-426.

Domning, D. P. 2001. Sirenians, seagrasses, and Cenozoic ecological change in the Caribbean. Palaeogeography, Palaeoclimatology, Palaeoecology 1:27-50.

Domning, D. P., and P. Pervesler. 2001. The osteology and relationships of Metaxytherium krahuletzi Depéret, 1895 (Mammalia: Sirenia). Abhandlungen der Senckenbergischen Naturforschenden Gessellschaft 553:1-89.

Marsh, H. D., T. J. O'Shea, and J. E. REynolds, III. 2011. Ecology and conservation of the Sirenia: dugongs and manatees. Cambridge University Press, 521p.

Reinhart, R. H. 1976. Fossil sirenians and desmostylids from Florida and elsewhere. Bulletin of the Florida State Museum, Biological Sciences 20:187-300.

Sorbi, S., D. P. Domning, S. C. Vaiani, and G. Bianucci. 2012. Metaxytherium subapenninun (Bruno, 1839) (Mammalia, Dugongidae), the latest sirenian of the Mediterranean Basin. Journal of Vertebrate Paleontology 32:686-707.

Toledo, P. M., and D. P. Domning. 1991. Fossil Sirenia (Mammalia: Dugongidae) from the Pirabas Formation (Early Miocene), northern Brazil. Boletim do Museu Paraense Emílio Goeldi, Série Ciencias da Terra 1:119-146.

Velez-Juarbe, J., D. P. Domning, and N. D. Pyenson. 2012a. Iterative evolution of sympatric seacow (Dugongidae, Sirenia) assemblages during the past ~26 million years. PLoS ONE 7(2):e31294.

Velez-Juarbe, J., J. I. Noriega, and B. S. Ferrero. 2012b. Fossil Dugongidae (Mammalia, Sirenia) from the Paraná Formation (late Miocene) of Entre Ríos Province, Argentina. Ameghiniana 49:585-593.

Zachos, J., M. Pagani, L. Sloan, E. Thomas, and K. Billups. 2001. Trends, rhythms, and aberrations in global climate 65 Ma to present. Science 292:686-693.

Return to the Caribbean side of Panama, pt. 2

A couple of Friday's ago, we were set to return to the locality where we had been excavating a relatively large whale skull. Last time we were there we manage to make the jacket around the skull, but the plaster did not dry quickly enough, and we had to leave it, as it was late in the day and the tide was coming in. Unfortunately, due to the change in time of the low tide (happening later and later in the day) as well as other technical problems, we could not go back as soon as we wanted. So we ended up waiting a whole week to return and hopefully finish the job.

A local girl, Pedro, Nicole and Samantha pose next to the jacket.

To our surprise, the jacket held up during the eight days that passed since we made it. Those were good news as it meant that our work and effort from the previous week was not lost and that we didn't had to make a new jacket. Plaster bandages are hard if not impossible to get here in Panama, so I was extremely happy we didn't had to use more than we already had.

Pedro, a local kid, Erik, Nicole and Samantha happily pose next to the large jacket as we get ready to move it to the truck.

We were able to remove the jacket and get it into our truck without further incidents, this wouldn't have been possible without the interns who are doing a great job! To top it off, we even found another tooth associated with the skull. Its not the first one, Aaron had already collected two, which were somewhat incomplete, but hinted at the affinities of the skull. The new tooth we collected is complete, and I can now confidently say that it belongs to a physeterid (a sperm whale)!! Sperm whales are found nowadays in the Caribbean, but their fossil record in the region is relatively poor, with only a handful of reports from a few sites. So this is a fantastic find!

One of the teeth associated with the skull in the jacket. Notice the large root and small enameled crown (to the left of the photo).

Stay tuned, as I'm sure we'll keep finding many other interesting fossils here in Panama.

Return to the Caribbean side of Panama

As part of the PCP-PIRE we not only get to look for fossils and study the geology of Panama along the canal. We also get to prospect and collect at other localities. Yesterday, we made the two hour drive to the Caribbean side of the country, where late Miocene marine units are exposed along the beach. If this sounds familiar, is because I had been there a couple of years ago, where, as part of the Pyenson Lab we went to collect a really nice fossil dolphin skull.

On our way to the locality we had to go through the Gatún Lock, and wait for several ships to go through before we could cross.

Going to this locality means we have to really plan ahead, as the late Miocene deposits will be best exposed at low tides. That also means that we only have about a four hour window to prospect and collect.

As the water recedes, the rock is exposed and its time to prospect!!

Ideally, we can find and collect specimens on a single day (within that 4 hour window), others may take longer, and require to return to the site one or more additional days.

Here Samantha and Pedro work on a project they stated with Aaron several months ago, excavating a large whale skull.

We worked two sites simultaneously this day. Pedro, Samantha and Erik continued an excavation they started several months ago with Aaron. They are digging around what seems to be a large whale skull. Nicole and I were about 15-20 meters southwest of where they were. We were busy digging what seems to be part of yet another whale skull. The skull seems to be broken or at least there's a skull and postcranial elements associated with it, so we collected these in two jackets (see picture below).

Here we take a break and have some snacks and talk with the local kids while the two small plaster jackets (center of the pictures) dry out so we can remove them and take them back to the lab.

We'll go back today to finish off the large whale skull, and who knows what else we'll find. So stay tuned!