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Figure 4 | BMC Evolutionary Biology

Figure 4

From: Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus) uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily

Figure 4

Maximum-likelihood reconstructions for the ancestral state of the sword in the genus Xiphophorus . Five different characters were mapped onto the nuclear tree: (a) a two-state character of sword extension (character 1), (b) a three-state character of sword extension (no sword, protrusion and sword; X. andersi was coded as a sworded species, character 2), (c) a three-state character of sword extension (X. andersi was coded as a species with protrusion, character 3) [26] and colored caudal extension with intermediate state (character 5), and (d) a two-state colored caudal extension (X. birchmanni was coded unknown, character 4) [27]. ML analyses of the character states, the colored caudal extension with polymorphic state (character 6), coloration (character 7) and the ventral black margin (character 8) of the sword, were not performed since Mesquite does not allow performing ML calculations on the characters that are polymorphic in some taxa. Each circle on the nodes represents character state (black filled circles: sword; green circles: protrusion or intermediate; empty circles: no sword; grey circles: unknown).

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