Histological aspects of the penial complex and vagina of taxa of the Biomphalaria tenagophila complex (Mollusca: Planorbidae)

Tatiane Eni Da Silva Tavares,Fernanda Pires Ohlweiler

doi:10.5007/2175-7925.2022.e82713

Abstract

Histological studies were carried out with 49 specimens; 18 Biomphalaria tenagophila guaibensis, 19 B. t. tenagophila and 12 B. occidentalis, collected in 10 municipalities in the states of São Paulo and Rio Grande do Sul, Brazil. The study considered histological aspects of the vagina, vaginal pouch and penial complex. In this study, we describe, for the first time, the histological features of the vagina, vaginal pouch and penial complex of B. t. tenagophila, B. t. guaibensis and B. occidentalis. The lining epithelial tissue and muscular tissue of the vagina, vaginal pouch and penial complex show a similar pattern in B. t. tenagophila, B. t. guaibensis and B. occidentalis, except for the intermediate muscular layer of the prepuce, which distinguishes B. t. guaibensis from the other two taxa. Histological studies on the penial complex and vagina region of other Biomphalaria species are necessary to confirm the taxonomic value of these two regions, in order to contribute to the group’s systematics.

Highlights

The Biomphalaria tenagophila complex, proposed by Spatz et al (1999), is represented by Biomphalaria tenagophila tenagophila (d’Orbigny, 1835), Biomphalaria tenagophila guaibensis Paraense, 1984 and Biomphalaria occidentalis Paraense, 1981
Lining epithelial tissue and muscular tissue with similar pattern are present in the vaginas of B. t. tenagophila, B. t. guaibensis and B. occidentalis and in the vaginal pouch of the two first taxa (Figure 1A)
The ciliated columnar lining epithelium found in the vagina of B. t. tenagophila, B. t. guaibensis and B. occidentalis and in the vaginal pouch of the first two taxa, absent in the last taxon, is observed in B. glabrata by Paraense and Deslandes (1955) and Pan (1958)

Summary

Introduction

The Biomphalaria tenagophila complex, proposed by Spatz et al (1999), is represented by Biomphalaria tenagophila tenagophila (d’Orbigny, 1835), Biomphalaria tenagophila guaibensis Paraense, 1984 and Biomphalaria occidentalis Paraense, 1981. The correct determination of the three taxa of the Biomphalaria tenagophila complex is important to identify the intermediate host species of S. mansoni, allowing the recognition of vulnerable areas for the transmission of schistosomiasis and, guiding health agents in surveillance and environmental control measures (BRASIL, 2008; PARAENSE, 2008). The penial complex and the vagina are the two regions of the reproductive system of greatest taxonomic importance in Biomphalaria (BAKER, 1945; ABDEL-MALEK, 1952); there are still many knowledge gaps surrounding the microanatomy of reproductive organs in these planorbid mollusks. Microanatomical studies of the penial complex and vagina region are important for the taxonomic delimitation of B. t. The present work aims to study the histological aspects of the penial complex and the vagina region of these three taxa, to contribute to the systematic of Planorbidae

Materials and Methods

Collection procedures

Results

Discussion