ANOMALIES OF MARSH FROGS OF PELOPHYLAX RIDIBUNDUS COMPLEX FROM WATER RESERVOIRS OF THE NATURAL PARK “BAUM’S GROVE” ON THE TERRITORY OF THE ALMATY CITY

Abstract

The aim of the study was to investigate anomalies and variability of a number of traits of external morphology of tadpoles, metamorphosed and juvenile individuals of marsh frogs of Pelophylax ridibundus complex from water reservoirs of the natural park “Baum’s Grove” of Almaty city. A total of 165 individuals from two samples were studied: a waterlogged pond near Bаskarasu River and a temporary reservoir in the Big Almaty Canal. The size characteristics of the studied specimens are given. It is revealed that in the second sample 2.8% of individuals had anomalies of hind limbs (ectromelia and taumelia, ectrodactyly, heterochrony). Individuals from both samples were characterized by a high percentage of larval mouthparts anomalies: 59.6% of tadpoles from the first sample and 67.4% in the second. The following types of abnormalities were noted: 1) ruptures of the dentition 2) loss of teeth; 3) complete or partial reduction of the dentition; 4) accretion of the dentition; 5) curvature and deformation of the dentition, 6) displacement and change of direction of the dentition; 7) deformation of the horny beak. A high percentage of individuals with 2-4 types of anomalies concurrently (74.2% in the first sample and 89.7% in the second sample) was found.

The obtained indicators repeatedly exceeded the threshold of the usual (background) occurrence of anomalies, as well as similar indicators for lake frogs from natural reservoirs in the south-east of Kazakhstan, which gives reason to classify them as massive. The article discusses possible reasons for the high frequency of occurrence of anomalies of the oral apparatus. As one of the main factors is considered the chemical and biological pollution of water reservoirs. In general, for a hybrid population of Marsh frogs, P. ridibundus from water reservoirs with anthropogenic load, data on the variability of signs of the external morphology of tadpoles, metamorphosed and juvenile individuals were obtained for the first time.