Rediscovering the Apaporis Caiman (Caiman crocodilus apaporiensis): Notes from a Long-Anticipated Expedition
Caiman crocodilus apaporiensis has been of particular interest because of its clearly differentiated morphotype within the Spectacled Caiman complex. Information on the biology of C. c. apaporiensis is incomplete because of its restricted distribution in the inaccessible middle and upper Apaporis River in Colombia. I undertook an expedition to the middle Apaporis River basin in an attempt to validate the presence of C. c. apaporiensis through observations on morphometry, ecology, and ethnozoology. Previously described skull characteristics were clearly differentiable in both adults and subadults in the region. However, because many individual C. c. apaporiensis that were either captured or visually assessed were relatively small, some skull characteristics more closely resembled the more general C. crocodilus morphotype. Although data on population size and distribution of C. c. apaporiensis remain limited, information gleaned from local inhabitants indicates that the subspecies is common in the middle Apaporis River. Population parameter and molecular phylogeography studies could lead to management practices that would protect the genetic integrity of C. c. apaporiensis by minimizing subspecific interbreeding.
Caiman crocodilus apaporiensis ha sido de particular interés debido a que su morfología está claramente diferenciada dentro del complejo de los caimanes de anteojos. La información en la biología del C. c. apaporiensis esta incompleta debido a su distribución restringida en la región media y superior del inaccesible rio Apaporis en Colombia. Emprendí una exploración a la cuenca de la región media del rio Apaporis en un intento de validar la presencia del C. c. apaporiensis a través de observaciones de morfometría, ecología, y etno-zoología. Las características del cráneo descritas por Medem (1955) fueron claramente diferenciables en ambos adultos y sub-adultos de la región. Sin embargo, debido a que muchos de los C. c. apaporiensis que fueron capturados fueron relativamente pequeños algunas de las características craneales fueron más cercanas a la morfología general del C. crocodilus. Aunque los datos de población y distribución del C. c. apaporiensis permanecen limitados, la información recabada de los pobladores indica que la subespecie es común a la mitad del rio Apaporis. Estudios sobre parámetros de la población y filogeografía molecular pueden concluir en practicas de control que puedan proteger la integridad genética de C. c. apaporiensis al minimizar la cruza dentro de la subespecie.
Abstract
Resumen
Study area highlighting the potential distribution area for Caiman crocodilus apaporiensis and all individuals seen across the five transects followed at the middle Apaporis River basin, Colombia.
Heads of Caiman crocodilus apaporiensis captured in the middle Apaporis River basin, Colombia. Scales on each side and labels represent the total head length (THL) in centimeters of each animal depicted. 4MTW, fourth mandibular tooth width; 4XTW, fourth maxillary tooth width; CPL, cephalic plate length.
Size class analysis depicting the proportions of juveniles and subadults (classes I and II) compared with reproductively mature animals (classes III and IV). Given the life history of crocodilians with a type III survivorship curve (low proportion of individuals surviving in the first stages of life; Milnes and Guillette, 2008), one should expect a large number of adults and fewer juveniles in a nonaffected population.
