Bark anole, A. distichus
I’ve been working on Abaco, in The Bahamas for several years now. The Bahamas, Abaco in particular, is famous for the abundance of terrific science that originates there. Currently, Abaco has three species of anole: A. sagrei, A. smaragdinus, and A. distichus. However, only A. sagrei has been considered native to the island, the others likely introduced relatively recently from islands of the Great Bahama bank such as New Providence or Bimini. However, a recent study reports fossil evidence of A. distichus in peat deposits from about 950 YBP supporting a long history of A. distichus on Abaco.
One interesting aspect of this find is that the contemporary distribution of A. distichus on Abaco appears to be limited to the main port town of Marsh Harbour. I always suspected that this limited distribution suggested that A. distichus was not native to the island, but rather came in on landscaping plants over the last several decades.
So why are there conflicting observations here? Is it possible that A. distichus was extirpated on Abaco due to settlement by indigenous peoples (seems to be contemporaneous with the fossil sediment formation)? While it might seems rather hard to extirpate such a small, abundant animal, there is growing evidence that the Bahamas were reptile-dominated ecosystems at the time of human arrival. Therefore, the coincident extirpation of tortoises, Cuban crocodiles, and rock iguanas places the modern hiatus of A. distichus in a different light. I am guessing that the altered (intensified) fire regimes initiated by ancient human civilizations may have contributed to the absence (rarity) of A. distichus from contemporary, natural ecosystems. This is admittedly, a lot of conjecture, but how else might one explain their ancient presence, yet contemporary confinement to a human-dominated habitat?
I look forward to hearing more from the interesting work that Dave Steadman, Janet Franklin and Nancy Albury are doing on these ancient Bahamas communities. And it looks like there is a lot more to come! Also, the name of the journal is The Holocene. How cool is that?!
Steadman DW, NA Albury, P Maillis, JI Mead, J Slapcinsky, KL Krysko, HM Singleton, and J Franklin. 2014. Late-Holocene faunal and landscape change in the Bahamas. The Holocene. DOI: 10.1177/0959683613516819.
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Anthony Geneva
Cool paper, thanks for pointing it out Sean! I’ve talked to you, James Stroud, and others about this offline before, I think the origin of “introduced” distichus populations in Florida and the northern Bahamas is really interesting. It would be great to determine the source of the extant Abaco populations. An even more exciting prospect would be to compare the fossil material to extant populations. It’s actually a possibility as ancient DNA has been recovered from moa fossils, preserved limestone buffered peat bogs in NZ (review article here ).
Sean Giery
Hi Anthony,
I do remember talking with you about this a few years ago. I guess there is still no resolution of the status of FL distichus? This fossil sure introduces an interesting wrinkle into both stories (i.e. Bahamas and Florida). This isn’t the first non-sagrei fossil they’ve found from the Little Bahama bank, so there might some other records out there of uncertain identity. I expect that there are quite a few more to come from their work in Blueholes. Most, if not all of the material goes to the FL Museum. Maybe worth checking with Ken Krysko about access to samples? Hope all is well.