We describe for the first time in precise anatomical detail new occurrences of petrified woods in the K5 formation of the Metangula Graben (Niassa, northern Mozambique), pertaining to the Capitanian (mid Permian). The two new species of fossil wood are described from two very well-preserved specimens. The two new species, Protaxodioxylon verniersii sp. nov. and Protaxodioxylon metangulense sp. nov. are characterized by showing tracheids with mixed radial pitting and taxodioid pits in the cross-field, typical of the genus Protaxodioxylon. The specimens described are mostly distinguishable from other Protaxodioxylon species by the absence of axial parenchyma, the height of rays and the number of pits per cross-field. Protaxodioxylon species reported to date were mostly restricted to the Northern Hemisphere and to the late Mesozoic (Jurassic and Cretaceous). Surprisingly, however, this study infers that this fossil wood genus has a significantly longer time range than previously thought and underwent dispersal and diversification even earlier during the Palaeozoic. Additionally, both specimens display distinct growth rings indicating that the fossil woods grew in an environment controlled by seasonal variation with partial suspension of growth in times of less water availability and/or lower temperature. On the other hand, the occurrence of Protaxodioxylon suggest a humid temperate, warm subtropical climate condition during the Capitanian in the Metangula Graben.

我们第一次以精确的解剖细节描述了 Metangula Graben（尼亚萨，莫桑比克北部）的 K5 地层中新出现的石化木，与 Capitanian（二叠纪中期）有关。从两个保存完好的标本中描述了这两种新的木材化石。这两个新物种Protaxodioxylon verniersii sp。十一月 和Protaxodioxylon metangulense sp。十一月 其特征是在交叉场中显示出具有混合放射状凹坑和紫杉二类凹坑的管胞，典型的Protaxodioxylon属。所描述的标本与其他Protaxodioxylon物种的主要区别在于没有轴向薄壁组织、射线高度和每个交叉场的凹坑数量。迄今为止报道的原二木属物种主要限于北半球和中生代晚期（侏罗纪和白垩纪）。然而，令人惊讶的是，这项研究推断，这个化石木属的时间范围比以前认为的要长得多，并且在古生代甚至更早的时候就经历了分散和多样化。此外，两个标本都显示出不同的年轮，表明化石木材生长在受季节性变化控制的环境中，在可用水量较少和/或温度较低时部分停止生长。另一方面，Protaxodioxylon的出现表明 Metangula Graben 的 Capitanian 期间处于潮湿的温带、温暖的亚热带气候条件。