Phymaturus of Patagonia Argentina: reproductive biology of Phymaturus zapalensis (Liolaemidae) and compared dimorphic traits in the genus.

BORETTO, J. E IBARGUENGOYTIA N. R

JOURNAL OF HERPETOLOGY

SOC STUDY AMPHIBIANS REPTILES

Año: 2009 vol. 43 p. 96 - 104

0022-1511

Lizards of the viviparous genus Phymaturus inhabit regions in which a significant proportionof the year is unsuitable for growth and reproduction. All Phymaturus studied have shown biennial female reproductive cycles. We studied the reproductive biology of Phymaturus zapalensis, which lives on rocky outcrops in cold and arid environments of Patagonia, Argentina. Male and female reproductive cycles, mean annual reproductive output, and sexual dimorphism were analyzed. Additionally, new dimorphic traits of Phymaturus antofagastensis and Phymaturus tenebrosus were compared with published data. The female reproductive cycle of P.  zapalensis  is annual-biennial (because  of skipping a  year of  reproduction), and synchronous with the annual male reproductive cycle. In midspring, males show spermatozoa in epididymis, and females have enlarged follicles, characteristic of imminent ovulation. The presence of 45% of the adult females with oocytes smaller than 4 mm, in all months of capture except October, suggests a year of skipped reproduction. Female P. zapalensis had greater SVL and a relative larger interlimb length than males. Males exhibited relatively greater head width, neck width, and diameter of front and hind legs. Our data indicate that  the  potential  for  annual  reproduction  exists  in  this  biennial  breeding  genus.  The  capability  of  P. zapalensis to perform either an annual or biennial reproductive cycle, instead of the characteristic biennialcycle  of  the  genus,  could  be  the  result  of  a  longer  activity  season,  higher  temperatures  during  spring, summer, and autumn months, together with a high-energy omnivorous diet.