Resumen

ROMERO-SCHMIDT, Heidi L; ORTEGA-RUBIO, Alfredo  y  ACEVEDO-BELTRAN, Marcos. Reproductive characteristics of the black-tailed brush lizard, Urosaurus nigricaudus (Phrynosomatidae). Rev. biol. trop [online]. 1999, vol.47, n.4, pp.1111-1115. ISSN 0034-7744.

The reproductive characteristics of Urosaurus nigricaudus at El Comitán, Baja California Sur, México, were determined through the necropsy of 33 males and 60 females during 1992. The average size of clutch per female was 4.06 + 1.86 eggs; 3.58 eggs for the first clutch and 4.75 eggs for the second clutch. Testicular size exhibits two peaks, one each in May and August. Female and male reproductive cycles are synchronized. In comparison with other Urosaurus species, U. Nigricaudus is atypical because males have two peaks of testicular mass.

Palabras clave : black-tailed brush lizard; Urosaurus nigricaudus; reproduction.