Flying primate hypothesis

In evolutionary biology, the flying primate hypothesis is that megabats, a subgroup of Chiroptera (also known as flying foxes), form an evolutionary sister group of primates. The hypothesis began with Carl Linnaeus in 1758, and was again advanced by J.D. Smith in 1980.[1] It was proposed in its modern form by Australian neuroscientist Jack Pettigrew in 1986[2] after he discovered that the connections between the retina and the superior colliculus (a region of the midbrain) in the megabat Pteropus were organized in the same way found in primates, and purportedly different from all other mammals. This was followed up by a longer study published in 1989,[3] in which this was supported by the analysis of many other brain and body characteristics. Pettigrew suggested that flying foxes, colugos, and primates were all descendants of the same group of early arboreal mammals. The megabat flight and the colugo gliding could be both seen as locomotory adaptations to a life high above the ground.

The flying primate hypothesis met resistance from many zoologists. Its biggest challenges were not centered on the argument that megabats and primates are evolutionarily related, which reflects earlier ideas (such as the grouping of primates, tree shrews, colugos, and bats under the same taxonomic group, the Superorder Archonta). Rather, many biologists resisted the implication that megabats and microbats (or echolocating bats) formed distinct branches of mammalian evolution, with flight having evolved twice. This implication was borne out of the fact that microbats do not resemble primates in any of the neural characteristics studied by Pettigrew, instead resembling primitive mammals such as Insectivora in these respects. The advanced brain characters demonstrated in Pteropus could not, therefore, be generalized to imply that all bats are similar to primates.

More recently, the flying primate hypothesis was soundly rejected when scientists compared the DNA of bats to that of primates. These genetic studies support the monophyly of bats.[4][5][6][7]

  1. ^ Pettigrew JD, Maseko BC, Manger PR (April 2008). "Primate-like retinotectal decussation in an echolocating megabat, Rousettus aegyptiacus". Neuroscience. 153 (1): 226–31. doi:10.1016/j.neuroscience.2008.02.019. PMID 18367343. S2CID 30649196.
  2. ^ Pettigrew JD (1986). "Flying primates? Megabats have the advanced pathway from eye to midbrain". Science. 231 (4743): 1304–1346. Bibcode:1986Sci...231.1304P. doi:10.1126/science.3945827. PMID 3945827.
  3. ^ Pettigrew JD, Jamieson BG, Robson SK, Hall LS, McAnally KI, Cooper HM (1989). "Phylogenetic relations between microbats, megabats and primates (Mammalia: Chiroptera and Primates)". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 325 (1229): 489–559. Bibcode:1989RSPTB.325..489P. doi:10.1098/rstb.1989.0102. PMID 2575767.
  4. ^ Springer, Ms; Teeling, Ec; Madsen, O; Stanhope, Mj; De, Jong, Ww (May 2001). "Integrated fossil and molecular data reconstruct bat echolocation". Proceedings of the National Academy of Sciences of the United States of America. 98 (11): 6241–6. Bibcode:2001PNAS...98.6241S. doi:10.1073/pnas.111551998. PMC 33452. PMID 11353869.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ Simmons, Nancy B.; Seymour, Kevin L.; Habersetzer, Jörg; Gunnell, Gregg F. (2008-02-14). "Primitive Early Eocene bat from Wyoming and the evolution of flight and echolocation" (PDF). Nature. 451 (7180): 818–821. Bibcode:2008Natur.451..818S. doi:10.1038/nature06549. hdl:2027.42/62816. PMID 18270539. S2CID 4356708.
  6. ^ Teeling, Ec; Springer, Ms; Madsen, O; Bates, P; O'Brien, Sj; Murphy, Wj (January 2005). "A molecular phylogeny for bats illuminates biogeography and the fossil record". Science. 307 (5709): 580–4. Bibcode:2005Sci...307..580T. doi:10.1126/science.1105113. PMID 15681385. S2CID 25912333.
  7. ^ Eick, Gn; Jacobs, Ds; Matthee, Ca (September 2005). "A nuclear DNA phylogenetic perspective on the evolution of echolocation and historical biogeography of extant bats (chiroptera)" (Free full text). Molecular Biology and Evolution. 22 (9): 1869–86. doi:10.1093/molbev/msi180. PMID 15930153.