El órgano de Bidder en sapos (Peltophryne spp.) endémicos de Cuba. Aspectos morfológicos y de ultraestructura / Bidder´s organ in Cuban endemic toads (Peltophryne spp.). Morphological and ultrastructural aspects

En los machos de algunas especies del genero Peltophryne, se ha descrito un organo vestigial frente a sus testiculos llamado organo de Bidder. A este organo se le ha atribuido funcion endocrina y la capacidad de convertirse en un ovario funcional como estrategia reproductiva de las especies de este grupo. En el presente trabajo se describe la ultraestructura del organo de Bidder en los machos de siete especies endemicas de sapos de Cuba: Peltophryne fustiger, P. peltocephala, P. taladai, P. florentinoi, P. longinasa longinasa, P l. cajalbanensis, P. l. dunni, P. gundlachi, y P. catalauciceps. Las gonadas se fijaron, en paraformaldehido al 4% para aplicar histologia clasica y DAPI y en glutaraldehido 2,5% para ser procesadas para Microscopia Electronica de Transmision. Los resultados muestran que la gonada de todos los machos estudiados tiene un organo de Bidder por encima de los testiculos en posicion craneal. La morfologia del organo Bidder muestra algunas diferencias entre especies. Este organo presenta dos zonas bien diferenciadas: corteza y medula y se aprecia la presencia de ovocitos en la primera. Alrededor de cada ovocito hay una sola capa epitelial de celulas foliculares con nucleolos en la periferia de la membrana nuclear, ribosomas y reticulo endoplasmatico rugoso, que indican sintesis de rRNA. No se detectaron diferencias entre los ovocitos previtelogenicos descritos en los ovarios y los presentes en el organo de Bidder. Se discute en el trabajo la presencia de las estructuras mencionadas y su posible funcion. Palabras clave: organo de Bidder, gonada, sapos, ultraestructura ABSTRACT Cuba has eight endemic frogs of the genus Peltophryne, an amazing presence in the entire area of the Caribbean. It is assumed that males of these toads have a vestigial organ in front of their testicles called organ Bidder that could become a functional ovary as a strategy of the species of this group or to have an endocrine function. However, this structure can be present also in females. The truth is that the information of their presence and function in males and females of the toads remains controversial and limited. The present work aims to show and explain the ultrastructure of the organ of Bidder in seven species of frogs from Cuba for the first time. Three Cuban males were used Peltophryne fustiger, P. peltocephala, P. taladai, P. florentinoi, P. longinasa longinasaP. longinasa, P. l. cajalbanensis, P. l. dunni, P. gundlachi, and P. catalauciceps. The gonads were extracted and were fixed, one of them in paraformaldehyde for applying classical histology and DAPI and the other in 2.5% glutaraldehyde to be processed for transmission electron microscopy. The results show that all studied male gonad has an organ of Bidder just above each cranial portion of the testicles. The morphology of the organ of Bidder shows some differences between Cuban toads. This body is composed of a cortex and medulla, being the last smaller than the cortex. Around each oocyte in the cortex of oocytes from Bider´s organ a single epithelial layer of follicular cells there are. No differences were detected between previtelogenic oocytes of ovary and those present in the Bider´s organ. All of them have follicular cells and nucleoli in the periphery of the nuclear membrane indicating a synthesis of rRNA. Also ribosomes and rough endoplasmic reticulum were observed. It´s discussed in the work the presence of these structures and their possible function. Keywords: Bidder´s organ, gonad, Cuban toads