Final answer:
Phylum Porifera, also known as sponges, does not have true tissues. Despite having specialized cells that perform specific functions like tissues, these tissues are not embryologically homologous to those found in other animal groups.
Step-by-step explanation:
The animal phylum that does not have true tissues is phylum Porifera. Porifera, also known as sponges, are parazoans, which means they lack true embryonically derived tissues. Although sponges have specialized cells that perform specific functions like tissues, these tissues are not embryologically homologous to those found in other animal groups.