Variación no geográfica de Microtus quasiater (Rodentia: Arvicolidae) con notas sobre su ecología y reproducción

Abstract

INTRASPECIFIC VARIATION WAS STUDIED IN 206 SPECIMENS OF MICROTUS QUASIATER, AN ENDEMIC SPECIES OF MEXICO INHABITING THE MONTANE HUMID FOREST IN A REDUCED ZONE OF THE SIERRA MADRE ORIENTAL AT AN ALTITUDE FROM 7OO TO 2150M. SEXUAL DIMORPHISM WAS ABSENT IN ALL THREE AGE CLASSES; WHEREAS THESE WERE SEPARATED BY THE TOTAL LENGHT AND BY 62% OF THE SKULL AND MANDIBULAR CHARACTERS WICH INCLUDE MOST LENGTHS AND WIDTHS RELATED TO THE ENLARGEMENT OF THE ROSTRUM AND MANDIBULE AS WELL AS WITH THE EXPANTION OF THE ZIGOMATICS. INDIVIDUAL VARIATION WAS MORE EVIDENT FOR EXTERNAL CHARACTERS (CV FROM 5.55 TO 26.72) THAN FOR MANDIBULAR AND CRANEAL CHARACTERS (CV FROM 2.53 TO 8.19). M. QUASIATER AND M. MEXICANUS WAS RECORDED IN THREE LOCALITIES OF PUEBLA. REPORTED ASSOCIATED FAUNA AS WELL AS THAT FOUD IN THE FIELD WORK IS MENTIONED. DATA FROM 46 SPECIMENS FROM 14 LOCALITIES SHOW THAT MALES WITH SCROTED TESTIS AND NURSING FEMALES OCCUR ALL OVER THE YEAR; WHEREAS PREGNANT FEMALES ARE ONLY PRESENT AT FALL AND WINTER. LITTER SIZE VARIED BETWEEN ONE AND FOUR EMBRIOS WITH AN AVERAGE OF TWO.