Sperm ultrastructure of the spider crab Maja brachydactyla (Decapoda: Brachyura)

Abstract

This study describes spermatogenesis in a majid crab (Maja brachydactyla) using electron microscopy and reports the origin of the different organelles present in the spermatozoa. Spermatogenesis in M. brachydactyla follows the general pattern observed in other brachyuran species but with several peculiarities. Annulate lamellae have been reported in brachyuran spermatogenesis during the diplotene stage of first spermatocytes, the early and mid-spermatids. Unlike previous observations, a Golgi complex has been found in mid-spermatids and is involved in the development of the acrosome. The Golgi complex produces two types of vesicles: light vesicles and electron-dense vesicles. The light vesicles merge into the cytoplasm, giving rise to the proacrosomal vesicle. The electron-dense vesicles are implicated in the formation of an electron-dense granule, which later merges with the proacrosomal vesicle. In the late spermatid, the endoplasmic reticulum and the Golgi complex degenerate and form the structures-organelles complex found in the spermatozoa. At the end of spermatogenesis, the materials in the proacrosomal vesicle aggregate in a two-step process, forming the characteristic concentric three-layered structure of the spermatozoon acrosome. The newly formed spermatozoa from testis show the typical brachyuran morphology.

Development of the male reproductive system in Callinectes ornatus Ordway, 1863 (Brachyura: Portunidae)

“…This reduction has also been observed in other crab species such as Ucides cordatus (Linnaeus, 1763) and in particular, in portunids such as C. sapidus, P. pelagicus and C. danae (Johnson, 1980;Castilho et al, 2008;Stewart et al, 2010;Ravi et al, 2012;Zara et al, 2012). However, in Maja brachydactyla Balss, 1922 no nuclear reduction was observed during spermiogenesis (Simeó et al, 2010). Callinectes ornatus did not show a difference between spermatogonia and primary spermatocytes, although the cells were smaller, differing from C. danae (Zara et al, 2012).…”

“…This crab supports an important smallscale fishery, as a bycatch of shrimp fishing (Severino-Rodrigues et al, 2001), and shows reproductive system. The male reproductive system has been studied in some brachyurans, including Portunidae (Cronin, 1947;Johnson, 1980;Stewart et al, 2010), Ucididae (Castilho et al, 2008), Eriphiidae (Erkan et al, 2009), Geryonidae (Hinsch and McKnight, 1988), Cancridae (Moriyasu et al, 2002), Grapsidae (Garcia and Silva, 2006), Epialtidae (Hinsch and Walker, 1974;Sal Moyano et al, 2009), Oregoneiidae (Beninger et al, 1988;Moriyasu and Benhalima, 1998;Sainte-Marie and Sainte-Marie, 1999), Inachidae (Diesel, 1989) and Majidae (Simeó et al, 2009(Simeó et al, , 2010.…”

Comparative ultrastructure of spermatozoa of the redclaw Cherax quadricarinatus and the yabby Cherax destructor (Decapoda, Parastacidae)

“…Niksirat et al (2014b) found that membranous lamellae detach from the cell after release of spermatozoa from the spermatophore. Simeó et al (2010) reported a similar region in the spermatozoa of spider crab Maja brachydactyla, called the SO-complex, consisting of membranes, mitochondria and occasionally microtubules. The origin of such complexes is usually considered to originate from the nuclear envelope, endoplasmic reticulum or Golgi apparatus Langreth, 1969;Reger, 1970;Kang et al, 2008).…”

Different aspects of reproduction strategies in crayfish: A review

“…Apart from its taxonomic and phylogenetic importance, knowledge of spermatozoal morphology can contribute to understanding the complex mechanisms of acrosome reaction and gamete fertilization (Simeo et al, 2010). The acrosome complex and nucleus are located at the anterior and posterior of the crayfish spermatozoon, respectively.…”