Characterization of Albanian water frog, Pelophylax shqipericus, sperm traits and morphology, by using phase contrast microscopy.

Mature spermatozoa traits and morphology of endangered Albanian water frog, Pelophylax shqipericus, have been characterized for the first time through phase contrast microscopy, as part of successful implementation of in vitro fertilization technique for this species. The basic morphology of P. shqipericus spermatozoa consists of an elongated, thick, smooth-edged, and solid-staining head, continuing with a thin and long tail which usually extends 2.48 times the head length. The acrosome was not clearly discernible so the measurements were done on the head as a whole, while the middle section was better visible. Average length of head, including the acrosome and midsection was estimated to be 11.78 μm ± 0.32, while the tail length resulted 29.24 ± 1.75 μm. The average thickness of the head was shown to be 3.45 μm. The total sperm length resulted to be 41.02 ± 1.83 μm. The average sperm concentration was estimated of 25.5 × 10 /ml. Sperm amount, survival rate and motility were also measured. The sperm survival rate was maximal immediately after preparation of the suspension and tended to decrease over time of storage, reaching 50% after 72 hr. Decreased sperm motility seemed to follow the same trend as sperm viability. Sperm traits resulted to be very similar both in size and in shape with those of "Lessonae" frog group, one of the lineages of Western Palearctic species complex, suggesting a strong phylogenetic relationship among these species.