Matrotrophy associated with vertebrates and especially mammals, matrotrophy is found in 21 of 34 animal phyla, and is fairly common in 11 of those. It has arisen independently in more than 150 clades within Chordata and in more than 140 clades amongst invertebrates. Matrotrophy Matrotrophy is a form of maternal care during embryo development. Some flowering plants supplied the developing embryos for the first stages. The ovule has no stocks and the nutrients are provided by the "mother". In plants, matrotrophy is considered a critical evolutionary development preceding the origin of embryophytes and therefore essential to the evolution of land plants.
Tullimonstrum characteristics of the well-known modern phyla, it was speculated that it was representative of a stem group to one of the many phyla of worms that are poorly represented today. Similarities with Cambrian fossil organisms were noted. Chen "et al." suggested similarities to "Vetustovermis planus". Others pointed to a general resemblance between "Tullimonstrum" and "Opabinia regalis", although Cave "et al." noted that they were too morphologically dissimilar to be related. In 2016 a morphological study showed that "Tullimonstrum" may have been a basal vertebrate, and thus a member of the phylum Chordata, with one study suggesting "Tullimonstrum" may be closely