| Sumario: |
The current knowledge of the precise extension and location of the androgenic gland (AG) in the genera Litopenaeus and Rimapenaeus is partial. Therefore, we analyzed the complete structure of the AG and cellular cord associated with the reproductive system of Litopenaeus setiferus, L. occidentalis, L. stylirostris, and Rimapenaeus byrdi at the stereoscopic microscopy and histological level. Our observations clearly show that the adult male reproductive system has a cellular cord that runs along the entire vas deferens. This cord is a blood vessel that runs along the ampoule, the descending and the ascending medial vas deferens. Terminal ampoules of the four species investigated have a gland-like tissue associated with the blood vessel that is attached to the external surface near to the chamber containing sperm; this structure was identified as the AG and is formed by a homogeneous mass of cells characterized by a small size (7 μm), a cytoplasm with discrete cell boundaries, and an oval nucleus (4 μm). The blood vessel is surrounded by massive layers of adipose tissue at the distal region of the ascending medial vas deferens, near to the large lumen that contains sperm. This tissue has large cells (2540 μm), with eosinophilic cytoplasms, and small nuclei (45 μm) in L.setiferus; L. stylirostris and L. occidentalis also show a cellular structure at the same location, identified as white adipose tissue. This anatomical description further improves the current knowledge of the general organization of the male reproductive system of Litopenaeus and Rimapenaeus.
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