Spermatogenic Cycle of the Florida Softshell Turtle, Apalone ferox
Spermatogenesis in Apalone ferox from Palm Beach County, Florida, is found to follow a postnuptial or dissociated pattern. Reduction of epididymis mass and clearing of sperm from the epididymides suggest spring mating. Histology of the testes, somatic index, and tubule diameter all suggest fall spermatogenesis. Males as small as 15.2 cm PL were found to be mature, and all males were reproductive in a given year. The distribution of postnuptial spermatogenesis is mapped on a phylogeny of turtles and suggests that this pattern has evolved at least six times among living turtles.Abstract
Monthly variation in testes and epididymides for Apalone ferox from Palm Beach County, Florida. Mean and SE given in (A), (B), and (D). Sample size for each monthly sample is given. (A) Somatic index (see Materials and Methods) by month for 97 samples, (B) epididymis mass index (see Materials and Methods) by month for 117 samples, (C) degree of sperm packing of epididymides (see Materials and Methods) monthly mean is given. (D) Seminiferous tubule diameter by month for 92 samples, (E) mean spermatogenic stage (modified from Licht, 1967) by month (see Appendix 2, Fig. 2)
Spermatogenic stage illustration. Photomicrigraphs of seminiferous tubules of Apalone ferox from Palm Beach County, Florida, showing seven stages of the testicular cycle (modified from Licht, 1967, see Appendix 2). Seven stages are represented: (a) Stage 1, (b) Stage 2, (c) Stage 3, (d) Stage 4, (e) Stage 5, (f) Stage 6, (g) Stage 7
The distribution of spermatogenic cycles among turtles. Prenuptial, postnuptial and acyclic patterns are shown as far as they are known for an outgroup and the families Chelidae, Chelydridae, Cheloniidae, Trionychidae, Dermatemydidae, Kinosternidae, Bataguridae, Emydidae, and Testudinidae. Tree topology is based on Gaffney and Meylan (1988) and Gaffney (1996)