The genus Stannophyllum

We obtained two sequences from a second species of Stannophyllum . This is the most species-rich xenophyophore genus and was placed by Haeckel (1889), Schultze (1907), Tendal (1972, 1996), together with a related genus Stannoma, in a distinct family, the Stannomidae, characterised by the presence of fine proteinaceous fibres that ramify the test. The new species groups with 100% bootstrap support with sequences from Stannophyllum zonarium, confirming that these are genuine Stannophyllum sequences. They consistently form a strongly supported (99% BV) group with Xenophyophore sp. 1. This is surprising since the only available material of Xenophyophore sp. 1 comprises tubular fragments that are morphologically completely different from Stannophyllum (Supplementary Figure 9c, d in Gooday et al., 2017a). The two sequences of Xenophyophore sp. 1 were obtained from one specimen and we would need additional material to examine and confirm its close molecular relationship with Stannophyllum .