Phylogenetics of South American Biomphalaria and description of a new species (Gastropoda: Planorbidae)

Abstract

The planorbid snail Biomphalaria edisoni n. sp. is described from morphological and molecular characters, based on specimens collected at two localities in Colombia. The new species has the typical features of the genus, as well as the following characteristics: vaginal pouch, numerous prostatic diverticula arranged in racemes, penis sheath/prepuce ratio of approximately 2 and a penial complex half the length of the cephalic portion of the female duct. These elements differentiate it from B. kuhniana, which was also present in one of the localities, and also from B. prona, B. helophila and B. nicaraguana, with which it has greater morphological similarities. Phylogenetic analysis of the nucleotide sequences of the internal spacers of the ribosomal DNA transcript (ITS1, ITS2) of B. edisoni n. sp. and 14 neotropical Biomphalaria species indicates that the former belongs to the monophyletic group including B. prona and B. sp. from Cuba. The genetic distances within this monophyletic group are however great enough for B. edisoni n. sp. to be regarded as a separate species. Thus morphology, phylogenetic tree topology and genetic distances all support the recognition of B. edisoni as a new species. MATERIAL AND METHODS Collection sites Material was collected from two sites. The Cali population was collected in February 2000 in the artificial lakes of the University of Valle del Cauca in Cali (3822 0 N, 76831 0 W), water temperature was 288C and pH 8.4. The Puente Iglesias population was collected on the west side of the El Sapo stream, 2 km upstream of the mouth of the Cauca river, in June-July 2001 at the Inspeccio´n Puente Iglesias, in the municipality of Fredonia (5848 0 N, 75840 0 W); they were found in fine sediments at depths of less than 5 cm in slow-flowing water with a temperature of 31-358C and pH 8.4. Morphological study Snails were transported live to the Medical Malacology Laboratory (MML) of PECET, where they were maintained in aquaria with artificially aerated dechlorinated water and a sterile mud substrate. They were fed on fresh lettuce. After 2 days of acclimatization, all the specimens were placed individually in vials containing dechlorinated water. These were exposed to a light source for 8 h as a stimulus to provoke the emission of cercariae. The snails that voided cercariae were then counted and installed in a specially conditioned aquarium. This assay was

Pattern of Genetic Divergence of Mitochondrial DNA Sequences in Biomphalaria tenagophila Complex Species Based on Barcode and Morphological Analysis

“…Nearly one -third of these species occur in freshwater ecosystems related to the main drainage river basins in Brazil (Estrada et al,2006;Teodoro,2010),where Biomphalaria glabrata (Say,1818),Biomphalaria tenagophila (Orbigny,1835) and Biomphalaria straminea (Dunker,1848) have serious impact on human health for these species host Schistosoma mansoni Sambon 1907 (Figure 1). Palasio, R.G.S., 2011) showing the worldwide distribution of the 37 Biomphalaria species, the 26 neotropical Biomphalaria species and the 11 species and 1 subspecies naturally described in Brazil (•) (Brasil,Ministério da Saúde 2007;Carvalho et al, 2008;Teodoro et al,2010).…”

Phylogenetic relationships and taxonomy of Altiplano populations of Biomphalaria (Gastropoda: Planorbidae): inference from a multilocus approach

“…The separate and combined analysis indicated that the sequences of B. costata from the Salar de Carcote (spring 1), its type locality (see Biese, 1951), never conform to a monophyletic group compared with those of B. peregrina , which groups with B. oligoza . In the 16S ML analysis the three sequences of B. peregrina from La Plata amplified in the present study formed a monophyletic group with two sequences of Mendoza and two from Brazil and Uruguay reported for this species (DeJong et al ., 2001; Estrada et al ., 2006); the molecular evidence does not support the synonymy established for these taxa. The COI data obtained by Collado et al .…”

“…The freshwater snails of the genus Biomphalaria Preston, 1910 are widely distributed in the Neotropical and African regions where some species are intermediate hosts of Schistosoma mansoni Sambon, 1907, a digenetic trematode which causes schistosomiasis (WHO, 1993, 1998). The taxonomy of Biomphalaria has been principally based on shell morphology and the anatomy of the reproductive system (Paraense, Fauran & Courmes, 1964; Paraense, 1966, 1981, 1984, 2003; Valdovinos & Stuardo, 1991), but the similarity of these characters among taxa has made classification difficult (Paraense, 1988; Estrada et al ., 2006). In fact, convergent shell evolution among African Biomphalaria species has been detected, complicating species identification using conchological characters (Plam et al ., 2008).…”

“… Taxa sequences incorporated in this study: a: DeJong et al ., 2001, b: Jørgensen et al ., 2007, c: Estrada et al ., 2006, d: Vidigal et al ., 2000c, e: Standley et al ., (unpublished); f: Tuan, R. & dos Santos, P. (unpublished); g: Present study; *: Chilean Altiplano localities. …”

Occurrence of Biomphalaria cousini (Mollusca: Gastropoda) in Brazil and its susceptibility to Schistosoma mansoni (Platyhelminths: Trematoda)

“…Although morphological studies of Biomphalaria species identification have been widely carried out, differentiation between some species may be complicated mainly due to phenotypic similarities, size of collected specimens and inadequate fixation procedures (Paraense, 1975). The difficulties involved in specific identification based on morphological characters have motivated the use of molecular techniques in conjunction with morphological characters (Caldeira et al, 1998;Vidigal et al, 2000a;Estrada et al, 2006).…”