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Ultrastructure of the spermatozoon of the American Alligator, Alligator mississippiensis (Reptilia: Alligatoridae)
Author(s) -
Gribbins Kevin M.,
Touzinsky Katherine F.,
Siegel Dustin S.,
Venable Katherine J.,
Hester Georgia L,
Elsey Ruth M.
Publication year - 2011
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.10984
Subject(s) - axoneme , biology , alligator , anatomy , american alligator , ultrastructure , spermatozoon , centriole , acrosome , nucleus , annulus (botany) , microbiology and biotechnology , flagellum , paleontology , botany , bacteria , semen
This study details the ultrastructure of the spermatozoa of the American Alligator, Alligator mississippiensis . American Alligator spermatozoa are filiform and slightly curved. The acrosome is tapered at its anterior end and surrounded by the acrosome vesicle and an underlying subacrosomal cone, which rests just cephalic to the nuclear rostrum. One endonuclear canal extends from the subacrosomal cone through the rostral nucleus and deep into the nuclear body. The neck region separates the nucleus and midpiece and houses the proximal centriole and pericentriolar material. The distal centriole extends through the midpiece and has 9 × 3 sets of peripheral microtubules with a central doublet pair within the axoneme that is surrounded by a dense sheath. The midpiece is composed of seven to nine rings of mitochondria, which have combinations of concentrically and septate cristae. The principal piece has a dense fibrous sheath that surrounds an axoneme with a 9 + 2 microtubule arrangement. The sheath becomes significantly reduced in size caudally within the principal piece and is completely missing from the endpiece. Dense peripheral fibers, especially those associated with microtubule doublets 3 and 8, penetrate into the anterior portion of the principal piece axoneme. The data reported here hypothesize that sperm morphology is highly conserved in Crocodylia; however, specific morphological differences can exist between species. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.