Cave Fieldwork in Cuba: 2002 - 2004

The early years of the new millennium were very productive for my research in Cuba. Our explorations, between 1995 and 2002, turned up very interesting fossils, representing rare and extinct faunas. The fruits of these explorations included two new records for Cuba, pertaining to two of the Caribbean's rarest fossil bats: the common vampire bat Desmodus rotundus and Peter's ghost-faced bat Mormoops megalophylla (articles can be downloaded here).

Fig. 1: An articulated skeleton of Mormoops blainvillei at Cueva de la Pluma (Cave of the Feather) in northern Matanzas, Cuba. This species is almost identical but smaller, than Mormoops megalophylla of the continent.

Our fieldwork began in the foothills of the Alturas Habana-Matanzas, a chain of lowland limestone hills that run W to E on the northern coast of Cuba. Uplift and exposure of these limestones during the last 5 million years has given origin to a vast cave region laden with fossil deposits, dating to the last glacial and inter-glacial period.

Fig. 2: Palenque Hill, a lowland limestone hill of the Havana-Matanzas range.
This is a karstic relict of uplifted Miocene seafloor that surrounded this region.

Within this region, we focused on a 200-meter high hill named Palenque (fig. 2-3). The hills of Palenque served as a shelter to runaway aborigines and slaves throughout the colonial period. A "palenque" is the name given to such a hideout. We selected this region mainly because of unstudied caves discovered in the 1980s, with an interesting biotic richness and endemism, characteristics that had attracted two of Cuba's foremost naturalists Carlos de la Torre and Johannes Gundlach a century before. They visited Palenque's hillside in search of unique mollusks, mammals, and birds.

Fig. 3: Karstic vegetation on the escarpment of Palenque hill, at about 180 meters above modern sea level.

A secondary but well preserved tropical semideciduous forest covers Palenque (fig. 3) with a flora that includes several kinds of trees including oaks and mahogany (Quercus and Swietenia spp.), gumbo limbo (Bursera simaruba), Royal Palms (Roystonea regia), plus other Thrinax-like palms in the upper levels. There is even coffee (Coffea arabica) brought into some caves by large fruit bats (Artibeus and Brachyphylla) and birds. Most of the lower level vegetation that extends to the agricultural savanna at the foothills include several kinds of grass, the poison ivy, locally known as Guao (Comocladia dodonea) and the toxic Chichicate (Urtica dioica).

Fig. 4. Main sinkhole of Nesfonte's cave, one of the largest cave of the Palenque, and probably the most extensive.
This is the main owl repository where most of the owl pellets have been accumulating for more than 2000 years. 

Fig. 5: The Cuban tarantula Phormictopus cubensis,  part of the penumbra cave fauna.

These fossil deposits originated from animal and plant remains mixed in with soil dragged into the caves by rainwater. Other were brought in by raptors, for example in vomitus, a form of hairball called pellet. Raptors, owls, and hawks do not fully digest bone and hair. Instead, they regurgitate them in the form of such pellets which accumulate in their cave roosts by the thousands (fig. 1, 6-7; note the round and brown pellet on the right of fig. 6). Because these raptors reuse the same roost areas from generation to generation their nests can include several thousand years of prey/pellet records. Even though their diet is selective, meaning they pick and choose from what prey is available in nature, theses pellets can provide a good record of the local fauna. The caves of Palenque provide an excellent record of that.

Fig. 6: A common vampire bat Desmodus rotundus skull in situ at the moment of discovery.
See the skulls of the brown bat Eptesicus fuscus (on far left) and large Cuban fruit bat Artibeus jamaicensis
skull (on upper right). A fresh owl pellet is next to the vampire bat skull,
 and some fresh material remains inside its braincase, testifying to its freshness.

The first serious discovery came from a newly discovered room in Cueva de la Caja or the Cave of the Box (fig. 3-4), also known as Cueva de Los Nesofontes or Nesofonte's cave, named so for the huge accumulation of Nesophontes fossil remains (more on this curious species on a future post). As archaeologist R. Viera and I explored a section of the cave, we accidentally stumbled upon a small mound on the floor of a newly discovered side room that had gone unnoticed on previous expeditions in 1994 and 2002 (Viera and Orihuela, 2006). In it, there were plant seeds scattered in a mound on the cave's floor and a vampire bat skull right on top like a cherry on the cream (fig. 6-8).

Figure 7: The vampire bat deposit as it looked before excavation on 22 December 2003.

What an interesting and unexpected discovery! At that time, vampire bats had been discovered only three times before, all exclusively from Cuba (Mayo and Woloszyn, 1974; Silva, 1979). As of today, vampire bats have not been discovered anywhere else in the greater Caribbean.

Desmodus rotundus is endemic to the New World neotropics, where it is well distributed from Mexico all the way down to northern Argentina, but in the past, that distribution included Florida, Cuba. The first fossil record came from Cueva Lamas in Havana. This fossil was discovered by Cuba's foremost paleontologist at the time Oscar Arredondo, who then sent the specimen to Dr. Karl Koopman, chiropterologist (=bat-ologist) who identified it as a common vampire bat Desmodus rotundus, identical to the continental species. In the following years, other researchers found two more specimens from which a new endemic subspecies, Desmodus rotundus puntajudensis, was erected (Woloszyn and Mayo, 1974; Jimenez et al., 2005). Later, the Cuban paleontologist William Suarez (Suarez, 2005) raised the species to the rank of full species, which made it a full Cuban endemic.

Fig. 8: Common vampire bat (Desmodus rotundus) after it's discovery at Nesophonte's cave.

However, the study of our well-preserved specimen (fig. 8-9) showed it was not referable to the new endemic form. Instead, our analysis of the skull characteristics of the continental form D. rotundus versus that of the endemic D. puntajudensis revealed that the Cuban fossils fell within D. rotundus, and did not represent a new form (Orihuela, 2011). This agreed with Koopman's original identification of the first specimen. As it seems, the Cuban fossil vamps are the same as the continental species, which may have arrived at the island during the last 10,000 years or less.

Fig. 9. Three of the four known Desmodus rotundus skulls from the Cuban Quaternary fossil record.
 Our specimen is on the far right. Line illustration from Orihuela, 2011 (copyrighted). 

An endemic form would suggest long isolation for such evolution to occur. And the presence of both, an endemic species (or subspecies) and the continental form, seems unlikely out of so poor of a record. So far, the fossil Desmodus specimens are associated with ages less than 8000 years before the present, and thus within our own current inter-glacial period, but none date to the late glacial period as was originally considered. In fact, we do not know if they were true relics of the past glacial fauna.

Osvaldo Jimenez Vazquez and his colleagues discovered vampire specimens from a cave deposit in southern Mayabeque province (formerly Havana province), providing the first radiocarbon date associated with vampire bat fossils in Cuba. Their remains dated, although indirectly, about 7000 years before the present (Jimenez et al., 2005). Our specimen posed a more complex problem and brought about new questions. They were dated, indirectly as well, between the 1950s to the 1990s (Viera and Orihuela, 2006; Orihuela, 2012; Orihuela et al. in prep.). Unfortunately, neither Cuban vampire fossil has been dated directly due to the rarity of the fossils.

Fig. 10: Pteronotus parnelli parnelli (Mormoopidae) from a transient local population at Nesophonte's cave.

What is sure is that there were vampire bats in Cuba until very recently, even if just accidentally. Our research using maximum entropy software such as Maxent, DIVA and R, employed to predict and model which bioclimate variables could have limited bat distribution, and if any of the variables could have lead to their extinction, suggests that the climate of the last 7000 years, up to our modern climate, is still appropriate to sustain many currently extinct Cuban bats including the vampire bats (work in prep.). Their extinction is considered concomitant to the extinction of the large sloths (like those I mentioned in my previous post here), which were likely part of their diet. Now we know that these sloths did not disappear during the late glacial epoch either, but instead during the last 5000 years, which is within our current inter-glacial.

So what does this mean? Where vampire bats accidentally present in the Cuban fossil record? If so, why are their fossils so rare considering how easily adaptable and reproducible the species is on the mainland? Are Desmodus fossils present in other Antillean fossil records? These are questions our current research is hoping to resolve. Stay tuned!

I want to take this opportunity to thank those that have helped on this research. First, I am eternally thankful to all those that participated in this expedition and those colleagues that helped with the analysis, their encouragement and help. These are archeologist Ricardo Viera, geographer Leonel Perez-Orozco, biologist Adrian Tejedor, Candido Santana and Joel Monzon, and many other more friends and colleagues that have made this research possible. These expeditions would have been impossible without their enthusiastic support.

This post is dedicated to the memory of Johannes Gundlach, whose birthday we celebrate today.

References

Atlas Nacional de Cuba 1969-1985.

Arredondo, O. 1958. El Vampiro Cubano. Scout 10:6-7.

Jiménez, O., M. M. Condis, and E. García. 2005. Vertebrados post-glaciales en un residuario fósil de Tyto alba scopoli (Aves: Tytonidae) en el occidente de Cuba. Revista Mexicana de Mastozoología, 9:84-111.

Koopman, K.F. 1958. A fossil vampire bat from Cuba. Breviora 90:1-4.

Silva-Taboada, G. 1979. Los Murciélagos de Cuba. Editorial Academia, La Habana. 424pp.

Orihuela, J. 2011. Skull variation of the vampire bat Desmodus rotundus (Chiroptera: Phyllostomidae): Taxonomic implications for the Cuban fossil vampire bat Desmodus puntajudensis. Chiroptera Neotropical 17(1): 963-976.

Orihuela, J. 2012. Late Holocene fauna from a cave deposit in Western Cuba: post-Columbian occurrence of the vampire bat Desmodus rotundus (Phyllostomidae: Desmodontinae). Caribbean Journal of Science, 46 (2): 297-313.

Orihuela, J., and A. Tejedor. 2012. Peter's ghost-faced bat Mormoops megalophylla (Chiroptera: Mormoopidae) from a pre-Columbian archaeological deposit in Cuba. Acta Chiropterologica 14(1): 63-72.

Orihuela, J., R. Viera, and L. Vinola. 2017. New bat records based on modern and fossil remains from the province of Matanzas, Cuba.

Suárez, W. 2005. Taxonomic Status of the Cuban Vampire Bat (Chiroptera: Phyllostomidae: Desmodontinae: Desmodus). Caribbean Journal of Science 41 (4):761-767.

Woloszyn, B.W., and N.A. Mayo. 1974. Postglacial remains of a vampire bat (Chiroptera: Desmodus) from Cuba. Acta Zool.Cracoviensia 19:253-265.