Litter Size and Relative Clutch Mass of the Earthsnakes Conopsis biserialis and C. nasus (Serpentes: Colubridae) From the Central Mexican Transvolcanic Axis

Abstract. Being highly secretive, cryptic in coloration, and infrequently active, most small fossorial snakes are poorly studied (How & Shine 1999, Goodyear & Pianka 2008). The colubrid genus Conopsis Günther, 1858 comprises six species (C. biserialis, C. nasus, C. acuta, C. amphisticha, C. megalodon, and C. lineata) of fossorial snakes that are endemic to México with a distribution ranging from the states of Chihuahua in the north to Oaxaca in the south (Goyenechea & Flores-Villela 2006). All species are viviparous and relatively small (adults of all species range from 100 to 330 mm in snout–vent length). Populations of these species occur mainly in pine and pine/oak forests, although they have also been collected in fir forests, xerophilous underbrush, submontane underbrush and deciduous forest, between ~1,500 and 3,200 m (Goyenechea & Flores-Villela 2006). Information about the biology and natural history of these species is markedly limited.