NOTA

Predation on Southern Turnip-tailed geckos (Thecadactylus solimoensis) by a Spectacled Owl (Pulsatrix perspicillata)

 

Juan D. Daza¹, Lee Bension Price², Christopher M. Schalk¹, Aaron M. Bauer³, A. Randall Borman⁴, Julian Kerbis Peterhans^2,5

¹ Department of Biological Sciences, Sam Houston State University, Huntsville, Texas 77341, United States of America.

² Science and Education, The Field Museum of Natural History, Chicago, Illinois, 60605, United States of America.

³ Department of Biology, Villanova University, Villanova, Pennsylvania 19085, United States of America.

⁴ Fundación para la Sobrevivencia del Pueblo Cofán, Mariano Cardenal N74-153 y Joaquín Mancheno Carcelen Alto, Quito, Ecuador

⁵ College of Professional Studies, Roosevelt University, Chicago, Illinois, 60605, United States of America.

Recibida: 30/11/16
Revisada: 21/02/17
Aceptada: 21/02/17

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ABSTRACT

We report on the predation of Thecadactylus solimoensis (Squamata, Phyllodactylidae) by an owl, Pulsatrix perspicillata (Aves, Strigiformes). Examination of pellets collected from a P. perspicillata roost contained a partial left maxilla of a gecko. The maxilla contained the following traits, which confirmed the identification of T. solimoensis: the large size of the maxilla, at least 27 tooth loci, a thickened medial side of the maxillary palatal shelf, a horizontal shelf at the base of the facial process, and blade like posterior process that does not taper abruptly. This is the first report of a gecko in the genus Thecadactylus being preyed upon by an owl.

Key Words: Diet; osteology; CT scans; Phyllodactylidae; Strigiformes.

Geckos of the genus Thecadactylus are widely distributed across the New World, and range from the Yucatán Peninsula in Mexico to northern Bolivia as well as across the Lesser Antilles (Russell and Bauer, 2002). Known predators of Thecadactylus geckos include a number of snake species (Leptophis ahaetulla [Hero and Magnusson, 1987], Siphlophis cervinus [da Cunha and Nascimento, 1994; dos Santos-Costa et al., 2015], Leptophis mexicanus [Campbell, 1998], Erythrolamprus cobella [Mole and Urich, 1894; Boos, 2001], Corallus caninus [Henderson, 1993], and Bothriechis schlegelii [Lindey and Sorrell, 2004]), Double-toothed Kites (Harpagus bidentatus [Haverschmidt, 1962]), bats (Goodwin and Greenhall, 1961; Tuttle, 1967; Greene 1988; Ferrer et al., 1998), and centipedes (Olson, 1993).

Birds are important predators of reptiles as their metabolic demands may impose strong selection on the evolution of defensive strategies (Greene, 1988; Pianka and Vitt, 2003). Owls are important consumers of small vertebrates and their regurgitated pellets contain the undigestible bones and hair of vertebrate prey, which facilitates the accumulation and fossilization of small vertebrate remains (Dodson and Wexlar, 1979). The analysis of these remains provides direct evidence about their trophic ecology and predator-prey interactions (Yom-Tov and Wool, 1997).

Here we report a partial left maxilla (Fig. 1) found in an owl pellet, recovered from Cuyabeno Wildlife Reserve, Ecuador (0° 23' 43.00'' S; 75° 54' 47.05'' W) along the margin of the Zabalo River. The pellet was regurgitated by a Spectacled Owl (Pulsatrix perspicillata). The maxilla belongs to a gecko according to diagnostic features of this group such as a single posterior process, and conical teeth with rounded crowns (Evans, 2008; Daza et al., 2015). There are four species of geckos in the Cuyabeno Wildlife Reserve area: O'Shaughnessy's Gecko (Gonatodes concinnatus; Sphaerodactylidae), Trinidad Gecko (Gonatodes humeralis; Sphaerodactylidae), Amazon Pigmy Gecko (Pseudogonatodes guianensis; Sphaerodactylidae), and Southern Turnip-Tailed Gecko (Thecadactylus solimoensis; Phyllodactylidae) (Miyata, 1982; Vitt and de la Torre, 1996). Based on the length of the maxilla, the length of the skull of the animal consumed by the owl is estimated to be about 20 mm long. Size alone serves to eliminate the three species of sphaerodactylids, which have miniaturized skulls which do not exceed 15 mm in length (Rieppel, 1984; Daza et al., 2008). Additional features support the identification as T. solimoensis, including tooth count (at least 27 tooth loci preser­ved and possibly more than 30 loci in total), a thickened medial side of the maxillary palatal shelf (where the bone contacts the ectopterygoid), a horizontal shelf at the base of the facial process, and a blade like posterior process that does not taper abruptly. This combination of traits are found on the lateral side of the bone in phyllodactylid geckos (Daza and Bauer, unpublished data).

Figure 1. Right maxilla of Thecadactylus solimoensis. (A-E) High Resolution Computer Tomography of specimen CAS 95146 (housed at the California Academy of Sciences) from Colonia Callería in the city of Pucallpa, region Ucayali, Peru. (F-H) material recovered from the owl pellets (material housed at The Field Museum, uncatalogued).

 

This report is the first to document an owl as a predator of geckos in the genus Thecadactylus. Because of their nocturnal habits, Thecadactylus geckos are vulnerable to predation by owls and other nocturnal predators. In this region, both species of Gonatodes and P. guianensis are diurnal (Vitt and de la Torre, 1996; Gamble et al., 2015), and are not likely to be prey of P. perspicillata.

Acknowledgements

We thank Alan Resetar, Rachel Grill, Gregory E. Schneider, and Jens Vindum for access to comparative material. We also thank Jessica Maisano from the University of Texas at Austin for assistance obtaining the computer tomography data.

 

Literature cited

1. Boos, H.E.A. 2001. The Snakes of Trinidad and Tobago. Texas A&M University Press, College Station, TX.         [ Links ]

2. Campbell, J.A. 1998. Amphibians and Reptiles of Northern Guatemala, the Yucatán, and Belize. University of Oklahoma Press, Norman, OK.         [ Links ]

3. da Cunha, O.R. & Nascimento, F.P. 1994. Ofídios da Amazônia. As cobras da região leste do Pará. Publicação Avulsa do Museu Paraense Emílio Goeldi 31: 1-218.         [ Links ]

4. Daza, J.D., Abdala, V., Thomas, R. & Bauer, A.M. 2008. Skull anatomy of the miniaturized gecko Sphaerodactylus roosevelti (Squamata: Gekkota). Journal of Morphology 269: 1340-1364.         [ Links ]

5. Daza, J.D., Bauer, A.M., Sand, C., Lilley, I., Wake, T.A. & Valentin, F. 2015. Reptile remains from Tiga (Tokanod), Loyalty Islands, New Caledonia. Pacific Science 69: 531-557.         [ Links ]

6. Dodson, P. & Wexlar, D. 1979. Taphonomic investigations of owl pellets. Paleobiology 5: 275-284.         [ Links ]

7. dos Santos-Costa, M.C., Maschio, G.F. & da Costa Prudente, A.L. 2015. Natural history of snakes from Floresta Nacional de Caxiuanã, eastern Amazonia, Brazil. Herpetology Notes 8: 69-98.         [ Links ]

8. Evans, S.E. 2008. The skull of lizards and tuatara, pp. 1-347. In: Gans, C., Gaunt, A.S. and Adler, K. (eds.), Biology of the Reptilia. Volume 20: Morphology H: The skull of Lepidosauria. Society for the Study of Amphibians and Reptiles, Ithaca, NY.         [ Links ]

9. Ferrer P. A., Lew, D. & Lasso A. 1998. Nota sobre depredación por Trachops cirrhosus Spix, 1823 (Chiroptera, Phyllostomidae) en Venezuela. Memoria 58: 145-148.         [ Links ]

10. Gamble, T., Greenbaum, E., Jackman, T.R. & Bauer, A.M. 2015. Into the light: diurnality has evolved multiple times in geckos. Biological Journal of the Linnean Society 115: 896-910.         [ Links ]

11. Goodwin, G.G. & Greenhall, A.M. 1961. A review of the bats of Trinidad and Tobago: Descriptions, rabies infection and ecology. Bulletin of the American Museum of Natural History 122: 191-301.         [ Links ]

12. Greene, H.W. 1988. Antipredator mechanisms in reptiles, pp. 1-152. In: Gans, C. and Huey, R.B. (eds.), Biology of the Reptilia. Volume 16.Alan R. Liss, New York, NY.         [ Links ]

13. Haverschmidt, F. 1962. Notes on the feeding habits and food of some hawks of Surinam. The Condor 64: 154-158.         [ Links ]

14. Henderson, R.W. 1993. On the diets of some arboreal boids. Herpetological Natural History 1: 91-96.         [ Links ]

15. Hero, J.M. & Magnusson,W. 1987. Leptophis ahaetulla. Food. Herpetological Review 18: 16.         [ Links ]

16. Lindey, S.D. & Sorrell, G.G. 2004. Bothriechis schlegelii (Eyelash Viper). Prey/predator weight ratio and diet. Herpetological Review 35: 272-273.         [ Links ]

17. Miyata, K. 1982. A check list of the amphibians and reptiles of Ecuador with a bibliography of Ecuadorian herpetology. Smithsonian Herpetological Information Service 54: 1|70.         [ Links ]

18. Mole, R.R. & Urich, F.W. 1894. Biological notes upon some of the Ophidia of Trinidad, B.W.I., with a preliminary list of the species recorded from the island. Proceedings of the Zoological Society of London 1894: 499-518.         [ Links ]

19. Olson, R.E. 1993. Brief notes on two Amazonian lizards. Bulletin of the Chicago Herpetological Society 28: 119.         [ Links ]

20. Pianka, E.R. & Vitt, L.J. 2003. Lizards: Windows to the Evolution of Diversity. University of California Press, Berkeley, CA.         [ Links ]

21. Rieppel, O. 1984. Miniaturization of the lizard skull: its functional and evolutionary implications, pp. 503|520. In: Ferguson, M.J.W. (ed.), The Structure, Development and Evolution of Reptiles. The Zoological Society of London, Academic Press, London, UK.         [ Links ]

22. Russell, A.P., & Bauer, A.M. 2002. Thecadactylus T. rapicauda. Catalogue of American Amphibians and Reptiles 753: 1-16.         [ Links ]

23. Tuttle, M.D. 1967. Predation by Chiropterus auritus on geckos. Journal of Mammalogy 48: 319.         [ Links ]

24. Vitt, L.J. & de la Torre, S. 1996. Guía para la Investigación de las Lagartijas de Cuyabeno. Museo de Zoología (QCAZ), Centro de Biodiversidad y Ambiente, Pontificia Universidad Católica del Ecuador, Monografía 1.         [ Links ]

25. Yom-Tov, Y.& Wool, D. 1997. Do the contents of barn owl pellets accurately represent the proportion of prey species in the field? The Condor 99: 972-976.         [ Links ]