title: Vocal sac development and accelerated sexual maturity in the lesser swimming frog, Pseudis minuta (Anura, Hylidae).
abstract: Sexual maturity involves the differentiation of the reproductive system, the maturation of germ cells, and the development of secondary sexual characteristics. Even though this topic has received much attention, little is known about the sequence of events that encompass reproductive maturation in anurans and what it could reveal about the developmental basis of life cycle evolution. The discovery of froglets of Pseudis minuta with incipient vocal sacs calling in breeding pools alongside several larger adult specimens with fully developed vocal sacs raised the question of the timing of sexual maturity in this species. Here we describe the sequence and timing of differentiation, development and maturation of the vocal sac apparatus and the testes in P. minuta (Anura, Hylidae), in order to establish a timeline of events leading to sexual maturity. Differentiation of the vocal sac apparatus begins at the final metamorphic stages, earlier than reported for other species, and the vocal sac acquires its final shape during the early postmetamorphic period. These modifications occur after gonadal differentiation, which begins early during the larval period and proceeds with a highly accelerated rate of development (e.g., secondary spermatids appear well before metamorphic climax), a situation reported previously for other anuran species only in the genus Pseudis. These results, together with a skeletochronological analysis showing that some calling specimens presented no lines of arrested growth, indicate acceleration in the timing of sexual maturity in Pseudis, and raise questions about the interdependence/decoupling during the development of the different components involved in reaching the adult stage.
authors: Instituto de Bio y Geociencias del NOA (IBIGEO-CONICET), CCT-Salta, 9 de Julio 14, 4405 Rosario de Lerma, Salta, Argentina. Electronic address: jgoldberg@conicet.gov.ar.
authors: Javier
authors: J
authors: Goldberg
authors: Instituto de Diversidad y Evolución Austral (IDEAus-CONICET), Bvd. Brown, 2915 Puerto Madryn, Argentina.
authors: Diego A
authors: DA
authors: Barrasso
authors: Grupo de Estudios sobre Biodiversidad en Agroecosistemas (GEBA), Instituto de Ecología, Genética y Evolución de Buenos Aires, (IEGEBA-UBA-CONICET), Universidad de Buenos Aires, Pabellón II Ciudad Universitaria C1428EHA CABA, Argentina.
authors: M Gabriela
authors: MG
authors: Agostini
authors: Instituto de Bio y Geociencias del NOA (IBIGEO-CONICET), CCT-Salta, 9 de Julio 14, 4405 Rosario de Lerma, Salta, Argentina.
authors: Silvia
authors: S
authors: Quinzio
mesh_terms: D000818:Animals; D001001:Anura / Q000254:growth & development*; D005260:Female; D007814:Larva / Q000254:growth & development; D008297:Male; D012741:Sexual Maturation / Q000502:physiology*; D013045:Species Specificity; D013737:Testis / Q000254:growth & development
keywords: Anurans; Gonadogenesis; Juvenile period; Life cycle; Vocal sac