Fig 1.
Schematic representation of snail shell morphometrics.
The abbreviations are provided in the Materials and Methods section.
Table 1.
DNA content (C-value) and relevant information of the analyzed samples in this study.
Fig 2.
Geographical localities and natural habitats of snails collected in Kenya.
The approximate localities are indicated. Detailed information for each locality (GPS) and its corresponding code is provided in Table 1. The photos in this figure were taken by the authors.
Fig 3.
Genome sizes (C-value) of Bulinus and Biomphalaria snails.
Detailed information for the codes is provided in Table 1. Codes Bi25, Bi26, and Bi27 represent the iM line Bi. glabrata (10.9 pg), BB02 Bi. glabrata (1.02 pg), and Bi. pfeifferi (0.91 pg), respectively, as reported by Bu et al. (2023) [29]. All samples of B. globosus are enclosed by dotted lines.
Fig 4.
Maximum Likelihood phylogram of complete mitochondrial genome sequences in Bulinus snails.
The tree is presented as a phylogram with branch lengths proportional to evolutionary distance (scale bar = 0.05 substitutions per site). Phylogenetic relationships were inferred using the GTR + G + I substitution model with 1,000 bootstrap replicates implemented in MEGA X [46]. A total of 21 complete mitogenome sequences (14,297 bp) were analyzed: 14 from the current study (BuF3, BuF16, BuTp7A, BuTp11, BuTp14, BuN6, BuN15, BuU4, BuU7, BuG1, BuG2, BuG5L, BuG12, and BuG13) and 7 published sequences, including 6 from Zhang et al. [26] and Biomphalaria glabrata (iM-line; MG431965.1) used as an outgroup. The tree demonstrates the phylogenetic relationships among major Bulinus species groups: the africanus group (including B. globosus, B. ugandae, and B. nasutus), the truncatus/tropicus complex, the forskalii group, and the reticulatus group. Branch lengths reflect the degree of evolutionary divergence between taxa.
Fig 5.
Maximum Likelihood phylogram of the mitochondrial COX1 gene in Bulinus snails from Africa.
The tree is presented as a phylogram with branch lengths proportional to evolutionary distance (scale bar = 0.05 substitutions per site). Phylogenetic relationships were inferred using the T92 + G + I substitution model with 1,000 bootstrap replicates implemented in MEGA X [46]. The analysis included 67 COX1 sequences (611 bp): 14 newly generated sequences from this study (indicated by specimen codes with GenBank accession numbers in parentheses) and 53 published sequences from GenBank representing several African Bulinus species and geographic localities. B. glabrata (iM-line; MG431965.1) was used as an outgroup.
Fig 6.
Shell morphology of bulinine specimens.
Details about the specimen codes, species, and their localities are provided in Table 1. The photograph was taken by S-MZ.
Fig 7.
Principal component analysis (PCA) of shell morphometric variables for Bulinus species.
(A) PCA plot including all Bulinus groups, showing the first two principal components that explain 40.8% and 38.7% of the total variance, respectively. (B) PCA plot excluding B. forskalii (BuF3), with the first two principal components explaining 57.3% and 15.4% of the total variance, respectively. Shapes represent different Bulinus groups, with symbol colors corresponding to taxonomic groups (africanus, forskalii, and truncatus/tropicus).
Fig 8.
A summary of the relationship patterns among bulinine species groups based on the current study and published papers.
References for each type of relationship (A, B, and C) are provided. The species studied from the B. reticulatus group is normally B. wright, as there are only two species (B. reticulatus and B. wright) in this group.