Reproduction and Growth of Typhlonectes compressicaudus: A Viviparous Gymnophione

Abstract

In Typhlonectes compressicaudus, a viviparous aquatic caecilian, males have a yearly cycle with spermatogenesis in June-July and copulation between Feb.-May. Females apparently have a biennial cycle. The first year, they are vitello-genic between Oct.-Feb.; at this period, ovulation occurs and gestation begins. Parturition occurs between July-Oct. Vitellogenesis occurs again very quickly. Oocytes are not mature during the second period of reproduction and they degenerate, becoming atretic follicles. Gestation lasts about six months. Newborn are fully metamorphosed. After 16 months they are mature; sperm can be observed in the testes and females can become pregnant. Comparison of our results with those of others indicates that reproduction is similar in those viviparous Gymnophiona for which data are available. THE first observations concerning repro-duction of Typhlonectes compressicaudus were made by Leprieur (Dumeril and Bibron, 1841) and Peters (1874a, b; 1875). The uro-genital apparatus and embryos were described by Fuhrmann (1914). Wake studied the testis and ovary (1968, 1977), the urogenital ducts (1970, 1977) and cloaca (1972) in several species and particularly in T. compressicaudus. Murphy et al. (1977) observed copulation in this species in captivity, as did Sprackland (1982). Barrio (1969) observed reproduction in captive Chthon-erpeton indistinctum, another viviparous species in the family Typhlonectidae. Wake (1980) an-alysed reproduction, growth and population structure of Dermophis mexicanus, a burrowing viviparous species in the family Caecilidae. Previously we reported on gestation (Exbray-at et al., 1981, 1982; Delsol et al., 1981) and sexual cycles (Exbrayat and Sentis, 1982; Ex-brayat, 1983; Exbrayat and Collenot, 1983) of T. compressicaudus. We also reported on repro-duction in this species in our laboratory (Ex-brayat and Laurent, 1983). The purpose of this paper is to report observations concerning the reproduction and growth of T. compressicaudus, both in the field and laboratory.