Troglomorphy: habitat dependent morphological divergence in two forms of a fish from Kotumsar Cave of Kanger Valley National Park, India

Abstract

Phenotypical adjustments of any organism with respect to their habitat are indeed a somatic/phenotypic plasticity phenomenon which has no genetic background. One can experience this particular phenomenon very easily in the case of cave organisms which are completing their phylogenetic race in a very uncommon biosphere. Enduring darkness, low energy inputs, limited air flow, are some of the basic environmental characteristics for any subterranean cave which altogether compel its inhabitants for various biological adjustments. Indeed the above harsh environmental factors have a high selective value in regard to adaptive features such as a drastic reduction in eye size and a reduced metabolic rate as compared to their immediate surface dwelling relatives. Any alteration in morphological, physiological, or behavioral feature in any cave inhabitant is referred as troglomorph. Troglomorphy in any cave species could be an outcome of constructive and/or regressive characteristics.
The cave dwelling fish of Kotumsar attracted worldwide researchers, since it came in limelight. It is because of the reason that in a single cave one can easily get two different troglomophs of a specific lineage. In addition, its immediate ancestral population is also easily traced up from the river flowing within few meters of this cave. The outcome of various comparative studies on physiologic and behavioural aspects among the above three forms have already substantiated a high degree of troglomorphy in the cave forms. Besides discussing various earlier reported troglomorphic characteristics of the cave populations, herewith we are presenting for the first time the comparative morphometric chart of the all the three forms existing in Kanger Valley National Park. Morphological measurements of the cave forms not only differ drastically from their nearest epigean population, but also appear to be different from the same population(s) reported elsewhere.

Keywords: Troglomorphism, cavefish, population mixing, geometric morphometrics, phenotypic plasticity
Poster Presented in :- International Colloquium on Endocrinology and Physiology, organized by -Indian Society for Comparative Endocrinology
29-30 September, 2014 at Raipur, C.G. India

Full text

TROGLOMORPHY: HABITAT DEPENDENT MORPHOLOGICAL DIVERGENCE
IN TWO FORMS OF AFISHFROM KOTUMSAR CAVE OF KANGER VALLEY
NATIONAL PARK, INDIA.
Jayant Biswas1* and Mausumi Dey1,2
1National Cave Research and Protection Organization, Central Zone,
Raipur, C.G., India
2Govt. Ghanshyam Singh Gupta P.G. College, Balod Dist. Balod (C.G.).
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Keywords: Troglomorphism, cavesh, 

./0