title: Sperm ultrastructure in Bathypolypus bairdii and B. sponsalis (Cephalopoda: Octopoda).
abstract: A morphological comparison of the spermatozoa of the octopods Bathypolypus bairdii and B. sponsalis has been carried out by electron microscopy. Although the mature spermatozoon of B. bairdii is longer and thinner than that of B. sponsalis, its general ultrastructure is similar except for some minor differences. Their characteristic acrosomes, described here for the first time, consist of a periodically banded cone surrounded by a double helix whose arrangement has been defined by a numeric expression. The plasma membrane of sponsalis that surrounds the acrosome has many projections filled with abundant granular cytoplasm, which appears as a star-shaped acrosome in cross-section. The mitochondrial sheath contains 9-11 mitochondria in bairdii but only 9 in sponsalis. A comparison with other Octopodidae shows that the nucleus of both species is the largest ever seen. Our results support the capability of sperm morphology to discriminate between species and could even discern at higher taxonomic levels.
authors.affiliation: Departamento de Ecología y Recursos Marinos, Instituto de Investigaciones Marinas (CSIC), 36208 Vigo, Spain. aroura@iim.csic.es
authors.forename: Alvaro
authors.initials: A
authors.lastname: Roura
authors.forename: Angel
authors.initials: A
authors.lastname: Guerra
authors.forename: Angel F
authors.initials: AF
authors.lastname: González
authors.forename: Santiago
authors.initials: S
authors.lastname: Pascual
mesh_terms: D000177:Acrosome / Q000502:physiology / Q000648:ultrastructure; D000818:Animals; D054468:Axoneme / Q000502:physiology / Q000648:ultrastructure; D002462:Cell Membrane / Q000502:physiology / Q000648:ultrastructure; D002467:Cell Nucleus / Q000502:physiology / Q000648:ultrastructure; D053145:Cell Nucleus Size / Q000502:physiology; D048429:Cell Size; D003593:Cytoplasm / Q000502:physiology / Q000648:ultrastructure; D003599:Cytoskeleton / Q000502:physiology / Q000648:ultrastructure; D005306:Fertilization / Q000502:physiology; D005407:Flagella / Q000502:physiology / Q000648:ultrastructure; D008297:Male; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000502:physiology / Q000648:ultrastructure; D049831:Octopodiformes / Q000502:physiology / Q000648:ultrastructure*; D013045:Species Specificity; D013094:Spermatozoa / Q000502:physiology / Q000648:ultrastructure*