Vertebrate Zoology 68(1): 65-82, doi: 10.3897/vz.68.e32226

Functional morphology of the lungs of the green iguana, Iguana iguana, in relation of body mass (Squamata: Reptilia)

Danilo Peixoto, Wilfried Klein, Augusto Shinya Abe, André Luis da Cruz

This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation: Peixoto D, Klein W, Abe AS, Cruz AL (2018) Functional morphology of the lungs of the green iguana, Iguana iguana, in relation of body mass (Squamata: Reptilia). Vertebrate Zoology 68(1): 65-82. https://doi.org/10.3897/vz.68.e32226

Abstract

Body mass is one of the most influencing factors of metabolic rate and gas exchange of animals, and also related to activity pattern and occupancyof ecological niches. This study aimed to understand the relationships between body mass (MB) and morpho-functional features ofthe lungs of Iguana iguana, through morphological and morphometric characterization of the structural elements of the respiratory system.Iguana iguana has lungs of the transitional type, the heterogeneously distributed parenchyma being faveolar in cranial and medial regionsand trabecular in the caudal region. Within the parenchyma, 43.6 ± 25.5% corresponds to faveoli, 18.0 ± 5.9% to interfaveolar septa, and38.7 ± 31.6% to trabeculae. Within the interfaveolar septa, 9.4 ± 4.0% corresponds to blood capillaries, 4.4 ± 1.0% to type I pneumocytes And 3.9 ± 1.1% to type II pneumocytes. Allometric analyses showed that lung (MB 0.8949) and parenchymal volume (MB 1.030) scale with MB in I. iguana just as in other lizards with unicameral or transitional lungs, which was unexpected for lung volume, since reptilian lung volume is generally considered to scale as MB 0.75. The functional orphology of the lungs in I. iguana seems to play an important role to meet the metabolic demands through ontogenetic growth.

Keywords

Lizard, respiratory morpho-functionality, gas exchange