Reproduction of Phymaturus cf. palluma

Viviparous  liolaemids  that  inhabit  cool  and  harsh  environments  of  Patagonia  and  the  highlands  of  the Andes exhibit distinctive life-history traits to synchronize births with benign environmental conditions.  We studied the reproduction of Phymaturus cf. palluma, a viviparous species that inhabits rocky outcrops in cool environments of the Andean highlands of San Juan, Argentina, and discuss our results in relation to the conservation status of this poorly  known  species.    We  determined  male  and  female  reproductive  cycles,  male  testosterone  cycle,  allometry  of morphometric variables and sexual size dimorphism, minimum adult size, clutch size, and mean annual reproductive output.  Females of Phymaturus cf. palluma exhibited a biennial reproductive cycle, with a litter size of one to two offspring, resulting in a low mean annual reproductive output of 0.75 offspring/female/year.  The male spermatogenic cycle  was  asynchronous  among  individuals.    We  observed  males  with  sperm  in  the  epididymis  and  high  values  of serum testosterone concentrations throughout the activity season.  The sexual dimorphism and allometric analyses revealed that legs are wider in males than in females throughout the life span, and not linked to sexual maturity.  In contrast, the head size in males and the trunk size in females are developed after sexual maturity, suggesting that they have arisen through sexual selection.  Our study confirmed a pattern of prolonged female reproductive cycles and low  mean  annual  reproductive  output  in  the  genus  Phymaturus,  resulting  in  this  species  having  one  of  the  lowest values of mean annual reproductive output for lizards in the world.

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