Thursday, January 15, 2009

A river runs through an Oligocene sea

The subject of this post is about my second and final day of fieldwork in Puerto Rico. Yes, I only managed to get two days of fieldwork because these were actually some very short vacations and on top of that it was very rainy. Anyways, I already wrote about my first day of fieldwork during which I searched for tetrapods in the Late Oligocene Lares Limestone. Now on my second day I went out to one of my favorite localities, herein referred to as Río G. This locality consists of exposures of the Early Oligocene age San Sebastián Formation along the banks of a river (See the picture below with me as scale and outcrops on each side of the river). The exposures along this river are considered as typical of the basal part of this formation (Monroe, 1980). The lithology of this formation is varied, with some layers representing ancient soils, river channels, deltaic deposits as well as marine units. Of course this is all in a sequence that makes sense with the tectonic history and paleogeography of the region, an interesting subject, which I will not touch at this moment, but might be discussed sometime in the future.

Now, some interesting tetrapods have been recovered from this formation, such as the sirenian Caribosiren turneri, described by Reinhart in 1959. Also from this formation are known pelomedusid turtles, which were previously discussed here. From the Río G locality, one of the more recent discoveries is the skull of the gryposuchine gavialid Aktiogavialis puertoricensis (Velez-Juarbe, et al. 2007). Other tetrapods found here, include sirenians, part of a croc axial skeleton and the oldest-but-crappiest rodent fossil from the Caribbean region. Some of these, like the sirenians are part of my thesis project, whereas the others are still awaiting description or for better material to turn up.

Unfortunately, same as with the prospecting in the Lares Limestone, no new or even useful vertebrate fossils were found in Río G. The most interesting fossil I found was a plant fossil that might be a seed or some sort of fruit (see picture below of the seed/fruit together with a schematic drawing – the fossil measures about 27 mm across). If it actually turns out to be a seed/fruit it would not be the first time that plant “megafossils” are found in the San Sebastián Formation; about 88 taxa of plant macrofossils from this formation were described by Sir Arthur Hollick in the 1920’s (Graham, 1996). I have yet to see Hollick’s (1926, 1928) papers; therefore I still don’t know if my fossil is similar to any of the material he described.

Well, at least since Río G is along a body of water, it turned out a nice place to do some bird watching. I have on previous occasions observed some of the birds along this river, with the difference that now I had a camera with a good zoom allowing me to take some nice pictures. The composite picture below include, clockwise beginning with the upper left: male Molothrus bonariensis (shiny cowbird); Butorides striatus (green-backed heron); Egretta caerulea (little blue heron); Actitis macularia (spotted sandpiper, this one has the winter plumage hence the lack of spots).

An interesting fact about the shiny cowbird is that it is an invasive species from South America, first reported from the Caribbean region during the latter half of the 1800’s (Post & Wiley, 1977a). It is also a brood parasite; in Puerto Rico it parasitizes about 16 different species of birds with a preference for the yellow-shouldered blackbird (Agelaius xanthomus) (Post & Wiley, 1977b; Pérez-Rivera, 1986). These are actually bad news as the yellow-shouldered blackbird is an endemic to the Puerto Rico bank.

On the earlier half of the day, while stalking a green-backed heron (Butorides striatus), I was unwillingly reminded to always keep an eye of where I put my feet. The reason was that while trying to stealthily sneak up to see where the bird was standing, I almost ended up stepping on a couple of fairly large green iguanas (Iguana iguana) (see composite picture below)!

This was actually the first time I have seen green iguanas in the wild in this part of the island. Iguanas are an introduced pest in Puerto Rico therefore their occurrence in this locality took me totally by surprise, although I am aware that they are getting more common around the island, specially in the east and north where it is more humid (I believe they are still not present in the drier southern coast or that they are much less common there). Green iguanas are doing really well in Puerto Rico; the reason might be that once they reach an adult size, nothing, except maybe humans, will eat them. Perhaps another reason for their success is that until several thousand years ago there were Anegada rock iguanas (Cyclura pinguis) in Puerto Rico (Pregill, 1981); are then green iguanas just filling in an empty niche left over by the extinction of the Anegada rock iguana from Puerto Rico? This is unlikely; rock iguanas (Cyclura spp.) are adapted to xeric environments, which, unlike today, were present in northern PR during the Pleistocene (Pregill & Olson 1981). This means that the habitat that was occupied by C. pinguis in northern Puerto Rico, no longer exist there (rock iguanas are not the only xeric-adapted tetrapod to go extinct in northern PR [op. cit.]). All I know is that from now on I will have to keep an eye out for green iguanas while doing fieldwork, at least in northern Puerto Rico.


Graham, A. 1996. Paleobotany of Puerto Rico-from Arthur Hollick’s (1928) scientific survey paper to the present. Annals of the New York Academy of Sciences 776: 103-114.

Hollick, A. 1926. Fossil walnuts and lignite from Porto Rico. Journal of the New York Botanical Garden 27:223-227.

Hollick, A. 1928. Paleobotany of Porto Rico. Scientific Survey of Porto Rico and the Virgin Islands 7(3):177-393.

Monroe, W. H. 1980. Geology of the middle Tertiary formations of Puerto Rico. US Geological Survey Professional Paper 953:1-93.

Pérez-Rivera, R. A. 1986. Parasitism by the shiny cowbird in the interior parts of Puerto Rico. Journal of Field Ornithology 57(2):99-104.

Post, W. & J. Wiley. 1977a. The shiny cowbird in the West Indies. Condor 79:119-121.

Post, W. & J. Wiley. 1977b. Reproductive interactions of the shiny cowbird and the yellow-shouldered blackbird. Condor 79:176-184.

Pregill, G. K. 1981. Late Pleistocene herpetofaunas from Puerto Rico. University of Kansas Museum of Natural History, Miscellaneous Publications 71:1-72.

Pregill, G. K. & S. L. Olson. 1981. Zoogeography of the West Indian vertebrates in relation to Pleistocene climatic cycles. Annual Review of Ecology and Systematics 12:75-98.

Reinhart, R. H. 1959. A review of the Sirenia and Desmostylia. University of California Publications in Geological Sciences 36(1):1-146.

Velez-Juarbe, J., C. A. Brochu & H. Santos. 2007. A gharial from the Oligocene of Puerto Rico: transoceanic dispersal in the history of a nonmarine reptile. Proceedings of the Royal Society B 274:1245-1254.

Monday, January 5, 2009

Publicaciones de fósiles de Puerto Rico / Publications on fossils from Puerto Rico

Para esta nota he recopilado un listado de publicaciones que tratan sobre fósiles de Puerto Rico. Por supuesto que el listado está viciado a favor de publicaciones sobre vertebrados fósiles los cuales son mis favoritos o invertebrados con los cuales he trabajado en el pasado. Si conoces referencias adicionales me puedes avisar (a través de correo electrónico o comentarios abajo) para asi añadirlos a la lista. Algunas de las referencias incluso están enlazados su pdf gratis.

For this post I have compiled a list of publications that deals with fossils from Puerto Rico. Of course it is somewhat biased toward vertebrates, which are my favorites or invertebrates on which I have worked on previous occasions. If you know additional references that are not here just let me know (either through emails or comments below) and they will be added. Some of these are linked to their free pdf.

Updated: 11/February/2016

Auffenberg, W. 1967. Notes on West Indian tortoises. Herpetologica 23(1):34-44.

Bermúdez, P. J., and G. A. Seiglie. 1970. Age, paleoecology, correlation and foraminifers of the uppermost Tertiary formation of northern Puerto Rico. Caribbean Journal of Science 10:17-33.

Bold, W. A., Van Den. 1965. Middle Tertiary Ostracoda from Northwestern Puerto Rico. Micropaleontology 11(4):381-414.

Choate, J. R. and E. C. Birney. 1968. Sub-recent Insectivora and Chiroptera from Puerto Rico, with the description of an new bat of the genus Stenoderma. Journal of Mammalogy 49(3):400-412.

Cutress, B. M. 1980. Cretaceous and Tertiary Cidaroida (Echinodermata, Echinoidea) of the Caribbean area. Bulletin of American Paleontology 77:1-221.

Domning, D. P. and O. A. Aguilera. 2008. Fossil Sirenia of the West Atlantic and Caribbean region. VIII. Nanosiren garciae, gen. et sp. nov. and Nanosiren sanchezi, sp. nov. Journal of Vertebrate Paleontology 28(2):479-500.

Gordon, W. A. 1963. Middle Tertiary echinoids of Puerto Rico. Journal of Paleontology 37(3):628-642.

Graham, A. 1996. Paleobotany of Puerto Rico-from Arthur Hollick’s (1928) scientific survey paper to the present. Annals of the New York Academy of Sciences 776: 103-114.

Graham, A. and D. M. Jarzen. 1969. Studies in neotropical botany. I. The Oligocene communities of Puerto Rico. Annals of the Missouri Botanical Garden 56:308-357.

Herrera, F., S. R. Manchester, J. Velez-Juarbe, and C. Jaramillo. 2014. Phytogeographic history of the Humiriaceae (Part 2). International Journal of Plant Sciences 175:828-840.

Hollick, A. 1926. Fossil walnuts and lignite from Porto Rico. Journal of the New York Botanical Garden 27:223-227.

Hollick, A. 1928. Paleobotany of Porto Rico. Scientific Survey of Porto Rico and the Virgin Islands 7(3):177-393.

Howell, B. F. 1966. New Upper Cretaceous sponge from Puerto Rico. Journal of Paleontology 40(1):207-209.

Hubbard, B. 1920. Tertiary Mollusca from the Lares district, Porto Rico. New York Academy of Sciences, Scientific Survey of Porto Rico and the Virgin Islands 3(2):79-164.

Iturralde-Vinent, M. A. 2001. Geology of the amber-bearing deposits of the Greater Antilles. Caribbean Journal of Science 17(3-4):141-167.

Mitchell, S. F., M. Martínez-Colón, R. Ramsook and H. Santos. 2012. A primitive tube-bearing antillocaprinid rudist bivalve, Parasarcolites sohli, sp. nov., from Jamaica and Puerto Rico, West Indies. Cretaceous Research 34:149-153.

Moussa, M. T. 1974. Tertiary brachiopods from Puerto Rico and their paleontologic and paleoecologic significance. Journal of Paleontology 48(6):1202-1206.

Olson, S. L. and Á. M. Nieves-Rivera. 2010. Fossil evidence and probable extinction of the greater fishing bat Noctilio leporinus (Chiroptera: Noctilionidae) on Isla de Mona, Puerto Rico. Mastozoología Neotropical 17(1):167-170.

Ortega-Ariza, D., E. K. Franseen, H. Santos-Mercado, W. R. Ramírez-Martínez, and E. E. Core-Suárez. 2015. Strontium isotope stratigraphy for Oligocene-Miocene carbonate systems in Puerto Rico and the Dominican Republic: implications for Caribbean processes affecting depositional history. Journal of Geology 123:539-560.

Pearson, P. N. and B. S. Wade. 2009. Taxonomy and stable isotope paleoecology of well-preserved planktonic foraminifera from the uppermost Oligocene of Trinidad. Journal of Foraminiferal Research 39(3):191-217.

Pessagno, E. A., Jr. 1963. Planktonic Foraminifera from the Juana Diaz Formation, Puerto Rico. Micropaleontology 9(1):53-60.

Pessagno, E. A., Jr. 1963. Upper Cretaceous Radiolaria from Puerto Rico. Micropaleontology 9(2):197-214.

Pisera, A., M. Martínez and H. Santos. 2006. Late Cretaceous siliceous sponges from El Rayo Formation, Puerto Rico. Journal of Paleontology 80(3):594-600.

Rabell-Cabrero, N. 1914. Notas paleontológicas. Revista de las Antillas 2(1):66-69.

Rabell-Cabrero, N. 1924. Notas sobre algunos escuálidos fósiles de Puerto Rico. Revista Agricultura de Puerto Rico 12:377-384.

Reinhart, R. H. 1959. A review of the Sirenia and Desmostylia. University of California Publications in Geological Sciences 36(1):1-146.

Sachs, K. N. 1959. Puerto Rican upper Oligocene larger Foraminifera. Bulletin of American Paleontology 39:399-416.

Schweitzer, C. E., M. A. Iturralde-Vinent, J. L. Hetler and J. Velez-Juarbe. 2006. Oligocene and Miocene Decapods (Thalassinidea and Brachyura) from the Caribbean. Annals of the Carnegie Museum of Natural History 75(2):111-136.

Sohl, N. F. 1992. Upper Cretaceous gastropods (Fissurellidae, Haliotidae, Scissurellidae) from Puerto Rico and Jamaica. Journal of Paleontology 66(3):414-434.

Sohl, N. F. 1998. Upper Cretaceous trochacean gastropods from Puerto Rico and Jamaica. Palaeontographica Americana 60:1-109.

Turvey, S. T. 2010. Evolution of non-homologous venom delivery systems in West Indian insectivores? Journal of Vertebrate Paleontology 30(4):1294-1299.

Turvey, S. T., F. V. Grady and P. Rye. 2006. A new genus and species of ‘giant hutia’ (Tainotherium valei) from the Quaternary of Puerto Rico: an extinct arboreal quadruped? Journal of Zoology 270:585-594.

Velez-Juarbe, J. 2014. Ghost of seagrasses past: using sirenians as a proxy for historical distribution of seagrasses. Palaeogeography, Palaeoclimatology, Palaeoecology 400:41-49.

Velez-Juarbe, J., and D. P. Domning. 2014. Fossil Sirenia of the West Atlantic and Caribbean region: X. Priscosiren atlantica, gen. et sp. nov. Journal of Vertebrate Paleontology 34:951-964. 

Velez-Juarbe, J. and D. P. Domning. 2015. Fossil Sirenia of the West Atlantic and Caribbean region: XI. Callistosiren boriquensis, gen. et sp. nov. Journal of Vertebrate Paleontology 35(1):e885034.

Velez-Juarbe, J. and H. Santos. 2008. Fossil Echinodermata from Puerto Rico; pp. 369-395 in W. I. Ausich and G. D. Webster (eds.), Echinoderm Paleobiology. Indiana University Press, Bloomington, Indiana.

Velez-Juarbe, J., T. Martin, R. D. E. MacPhee, and D. Ortega-Ariza. 2014. The earliest Caribbean rodents: Oligocene caviomorphs from Puerto Rico. Journal of Vertebrate Paleontology 34:157-163.

Wetmore, A. 1920. Five new species of birds from cave deposits in Porto Rico. Biological Society of Washington, Proceedings 33:76-81.

Woods, C. A. 1996. The land mammals of Puerto Rico and the Virgin Islands. Annals of the New York Academy of Sciences 776:131-149.