Eckelbarger Kevin J, Bieler Rüdiger, Mikkelsen Paula M
Reproductive Biology Program Harbor Branch Oceanographic Institution, Fort Pierce, Florida 34946.
Department of Malacology, Delaware Museum of Natural History, Wilmington Delaware 19807.
J Morphol. 1990 Jul;205(1):63-75. doi: 10.1002/jmor.1052050107.
Ultrastructural features of the ovotestes, spermatogenesis, and the mature sperm are described for three galeommatid bivalves, Divariscintilla yoyo, Divariscintilla troglodytes, and Scintilla sp., from stomatopod burrows in eastern Florida. All three species yielded similar results except with respect to mature sperm dimensions. The ovotestis contains three types of somatic cells within the testicular portion: flattened myoepithelial cells defining the outer acinal wall; underlying pleomorphic follicle cells containing abundant glycogen deposits; and scattered, amoeboid cells containing lysosomal-like inclusions which are closely associated with developing sperm. Early spermatogenesis is typical of that reported from other bivalves. In contrast, the late stages of spermiogenesis involve the migration and gradual rotation of the acrosomal vesicle, resulting in a mature acrosome tilted about 70° from the long axis of the cell. The mature sperm possesses an elongated, slightly curved nucleus; a subterminal, concave acrosome with a nipple-like central projection; five spherical mitochondria and two centnoles in the middlepiece; and a long flagellum. The rotational asymmetry and the presence of perimitochondrial glycogen deposits in these sperm are unusual in the Bivalvia and may be associated with fertilization specializations and larval brooding common among galeommatoideans.
描述了来自佛罗里达州东部口足类动物洞穴中的三种海螂目双壳贝类——尤约双带蛤（Divariscintilla yoyo）、穴居双带蛤（Divariscintilla troglodytes）和闪烁蛤属（Scintilla sp.）的卵精巢、精子发生及成熟精子的超微结构特征。除成熟精子尺寸外，这三个物种的结果相似。卵精巢的睾丸部分包含三种类型的体细胞：界定腺泡外壁的扁平肌上皮细胞；含有大量糖原沉积物的多形卵泡细胞；以及含有溶酶体样内含物且与发育中的精子紧密相关的散在变形细胞。精子发生早期与其他双壳贝类报道的典型情况相同。相比之下，精子形成后期涉及顶体囊泡的迁移和逐渐旋转，导致成熟顶体与细胞长轴倾斜约70°。成熟精子具有细长且略弯曲的细胞核；亚末端、凹陷的顶体，中央有乳头样突起；中段有五个球形线粒体和两个中心粒；以及一条长鞭毛。这些精子中的旋转不对称以及线粒体周围糖原沉积物的存在在双壳纲中并不常见，可能与海螂目常见的受精特化和幼体育幼有关。
