How four sympatric lizard species reproduce in the subtropical region of Wet Chaco of Argentina?

ORTÍZ, MARTÍN; IBARGÜENGOYTÍA, N.R.; BORETTO, J.M.

Hangzhou

Congreso; 8th World Congress of Herpetology; 2016

Squamates exhibit a variety of reproductive strategies within and between lineages that has been assigned to phylogeny, environment factors, or both. Herein, we studied the reproductive cycles of four sympatric South American lizards that inhabit the Wet Chaco of Argentina, the oviparous species Tropidurus catalanensis (Tropiduridae) and Kentropyx viridistriga (Teiidae), and the viviparous species Ophiodes intermedius (Diploglossidae) and Mabuya dorsivittata (Scincidae). The male gonads were removed and processed by histological techniques. In females, we registered the presence and number of vitellogenic follicles, oviductal eggs/embryos, and corpora lutea. We found that the two oviparous species showed multiple clutches, but they strongly differ in their reproductive cycles and activities. Tropidurus catalanensis males showed continuous spermatogenesis throughout the year, although the maximum gonadal activity occurs in spring; and females exhibited a seasonal reproductive cycle restricted to spring-summer. In contrast, Kentropyx viridistriga exhibited brumation during winter and spring, and a synchronous reproductive activity between males and females from early summer to autumn. The viviparous semifossorial Ophiodes intermedius exhibited asynchronous reproductive cycles between sexes, with maximum spermatogenic activity in autumn, and stores sperm in epididymis or deferens duct throughout the year. Females ovulate macrolecithal oocytes in spring, and births occurred between late springs to early summer, after 3-4 months of gestation. Mabuya dorsivittata showed a seasonal, annual and associated male and female cycle. Female ovulate microlecithal oocytes in midsummer, and births occurred during the following spring to early summer, after 10-11 months of gestation. The maximum spermatogenic activity in males was observed in late spring, coinciding with the beginning of the time of birth. We found different reproductive strategies between the four sympatric species studied, but their reproductive cycles are similar to their counterparts in other regions, suggesting there is a strong phylogenetic component that would explain the reproductive phenotypes observed.