%0 Journal Article
%T Sperm storage in caecilian amphibians
%A Susanne Kuehnel
%A Alexander Kupfer
%J Frontiers in Zoology
%D 2012
%I BioMed Central
%R 10.1186/1742-9994-9-12
%X In the oviparous Ichthyophis cf. kohtaoensis, aggregated sperm were present in a distinct region of the posterior oviduct but not in the cloaca in six out of seven vitellogenic females prior to oviposition. Spermatozoa were found most abundantly between the mucosal folds. In relation to the reproductive status decreased amounts of sperm were present in gravid females compared to pre-ovulatory females. Sperm were absent in females past oviposition.Our findings indicate short-term oviductal sperm storage in the oviparous Ichthyophis cf. kohtaoensis. We assume that in female caecilians exhibiting high levels of parental investment sperm storage has evolved in order to optimally coordinate reproductive events and to increase fitness.Animal reproductive strategies include variable modes of sperm transfer, fertilization, and type of offspring development. In particular female sperm storage, where male spermatozoa remain in the reproductive tract after mating until used for fertilization, has evolved independently and repeatedly in metazoans as a mechanism to temporarily decouple insemination from fertilization [1,2]. In vertebrates, female sperm storage in dedicated structures occurs in all major lineages with durations ranging from a few hours or days in most mammals (not including bats) to long-term storage up to months in sharks, turtles, birds and also reptiles with a reported maximum of seven years [2]. Among modern amphibians many female salamanders can store sperm in unique cloacal spermathecae [3] and internal fertilising anurans such as tailed frogs (Ascaphus ssp.) have sperm storage in the oviducts [4]. This raises the question whether female sperm storage has also evolved in the third group of extant amphibians, the limbless caecilians [5,6].Caecilians perform internal fertilization with the aid of an intromittent organ [7,8] and show various extraordinary reproductive strategies including maternal dermatotrophy and intrauterine feeding [9,10]. We investigated
%K Reproduction
%K Sperm storage
%K Amphibians
%K Caecilians
%U http://www.frontiersinzoology.com/content/9/1/12