SPERM STRUCTURE OF THE PANDALID SHRIMP PANDALOPSIS JAPONICA (DECAPODA, PANDALIDAE)

Abstract

The sperm structures of pandalid shrimps were previously undescribed. We determined the mature sperm morphology and ultrastructure of Pandalopsis japonica by means of light and electron microscopy and compared them with the known morphology and ultrastructure from other carideans. Spermatogenesis is initiated in the testicular tissue of the male-phased Pandalopsis japonica ranging from 14 to 23 mm in carapace length. The sperms are 52 to 55 μm in length and consist of a cup-shaped main body and a spike extending from the convex surface of the main body. The main body, of which the size is 24 to 26 μm in width and 5 to 7 μm in height, has a nucleus and a cup-shaped base. The spike, 40 to 44 μm long and approximately 3 μm thick, consists of the central core filled with electron-lucent materials and the electron-dense wall containing a number of tubular-like structures that are aligned along the longitudinal spike. The unique structure of Pandalopsis japonica sperm, particularly in the spike possessing tubular-like structures of approximately 24 nm in the outside diameter and 15 nm in the inside diameter, offers a good taxonomic tool among shrimp species in the carideans.