Studies On The Respiratory Organs of Acanthophthalmus Pangia Gunther: An In-depth Analysis

Studies On The Respiratory Organs of Acanthophthalmus Pangia Gunther: An In-depth Analysis

Sources and Citation

• University: Babasaheb Bhimrao Ambedkar Bihar University
• Author: W. John Singh
• Year: 1991
• Degree: Doctor of Philosophy (in Zoology)
• Department: Department of Zoology
• College: Mayai Lambi College, Yumnam Huidrom, Manipur

An Academic Study of Acanthophthalmus Pangia’s Respiratory System

The evolution of vertebrates from water-breathing to air-breathing is a significant event in zoology, presumed to be an adaptive response to environmental changes. The Devonian period, for instance, saw a rise in temperature and a corresponding decrease in the oxygen content of water. This led to the development of auxiliary aerial respiration in certain freshwater fishes.

This study focuses on Acanthophthalmus pangia, an air-breathing fish from North-Eastern India. It has adapted to obtain oxygen from the atmosphere. The research aims to define the structure of its gills and the modifications in its intestine from a respiratory perspective.

The study is divided into four chapters, covering the bionomics of the fish, gill morphology, the gastro-intestinal tract’s role in aerial respiration, and a histochemical study of the gut. The findings highlight the dual respiratory mechanism of the fish, where both the gills and the modified gut contribute to meeting its oxygen demands.

Unveiling the Mystery of Air-Breathing

The central research problem addressed in this thesis is to understand the anatomical and histological adaptations that enable Acanthophthalmus pangia to survive in oxygen-depleted aquatic environments. The study investigates how this specific species compensates for its oxygen needs through air-breathing organs, particularly when its typical gill respiration becomes insufficient due to adverse conditions such as a drop in water oxygen levels during the summer.

The research aims to provide a detailed account of the structures involved and their modifications for this unique form of respiration. This provides crucial insight into the highly specialized Acanthophthalmus pangia respiratory organs.

The Methodology Behind the Discovery

The investigation was carried out by collecting Acanthophthalmus pangia specimens from the Manipur or Imphal river near SEKMAIJIN, which is located about 30 km south of Imphal. The methodology involved a detailed examination of the fish’s respiratory organs, including the gills and the gastro-intestinal tract.

A light and SEM (Scanning Electron Microscope) study was conducted on the gill morphology to understand its structure. A histochemical study was performed on the gastro-intestinal tract to analyze the cellular modifications that facilitate aerial respiration. The study also incorporated observations of the fish’s behavior, such as burrowing into sand or mud and surfacing to gulp air.

Key Findings of the Study

The study’s findings reveal that Acanthophthalmus pangia has developed remarkable adaptations for aerial respiration. The gastro-intestinal tract is modified to function as an air-breathing organ, where gaseous exchange occurs between inhaled air and the blood circulating through a fine network of capillaries in the gut epithelium.

The intestinal wall has become thin and elastic due to the reduction of smooth muscle layers and submucosa, and the presence of a well-developed collagen layer. The diffusion distance for the air-blood pathway in the intestine was found to be 2.4 um thick, a testament to its efficiency.

The gills, while well-suited for aquatic respiration, are supplemented by this intestinal system, allowing the fish to survive in low-oxygen conditions. Interestingly, the gills also possess sensory papillae and taste buds, suggesting a role in analyzing the chemical nature of food and water, analogous to the tongue of vertebrates.

Significance of the Research

This study holds significant importance in the field of zoology as it provides a detailed understanding of the unique respiratory mechanisms of Acanthophthalmus pangia. By defining the structure and modifications of both the gills and the gastro-intestinal tract, the research contributes valuable insights into the evolutionary process of air-breathing in vertebrates.

The findings demonstrate how a single organism can possess two distinct and equally sufficient respiratory systems, a crucial adaptation for survival in challenging aquatic environments. The research also sheds light on the histological changes that occur to enable such a physiological shift, offering a foundation for future studies on similar species and the broader topic of fish physiology and evolution. This thesis stands as a pivotal work on Acanthophthalmus pangia respiratory organs and their functionality.

Full thesis pdf