ISSN:
1432-1793
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The spermatozoa of four species of the patellogastropod family Lottiidae (Lottia pelta, L. digitalis, L. strigatella, Tectura scutum) and one species of the archaeogastropod family Fissurellidae (Diodora aspera) were examined in 1990 using transmission electron microscopy. All have primitive or ect-aquasperm, typical of invertebrates using external fertilization. Sperm of the lottiid limpets are characterized by a 5 to 9 μm-long head composed of a conical acrosome which constitutes 〉50% of the head length, and a cylindrical nucleus. The acrosome of all species of lottiids is differentiated internally, and has a posterior invagination ≈0.9 to 1 μm in depth, into which an elongate acrosomal lobe protrudes. Between the posterior acrosomal lobe and the nucleus, the subacrosomal material is aggregated as a fibrous column. The midpiece of the sperm has a ring of 4 to 5 spherical mitochondria of ≈0.6 μm diam, posterior to which is a collar of cytoplasm ≈1 μm long, which sheaths the anterior portion of the axoneme. The size and morphology of the acrosome and large cytoplasmic collar clearly distinguish the spermatozoa of the Lottiidae from other families of Patellogastropoda. The sperm of D. aspera (Fissurellidae) is typical of the family of archaeogastropod; the head has a length to breadth ratio of 4:1, and the cylindrical nucleus is capped by a small acrosome, 〈25% of the total head length, which is deeply invaginated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00350736
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