Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       Astra Plinius - celestial bodies
         Universe
           (Supercluster) Virgo-Hydra-Centaurus Supercluster
             (Supercluster) Virgo Supercluster
               (Cluster) Local Group
                 (Galaxy) Milky Way Galaxy veter.
                   (Spiral arm) Orion Arm
                     (Region) Local Bubble
                       Local Interstellar Cloud
                         (Planetary system) Solar System
                           (Planet-satellite system) Earth System
                             (Planet) Earth veter.
                               "spheres" (Earth)
                                 (Sphere) Biosphere (Earth) - zone of life
                                   "marine ecoregions"
                                     (Region) Indo-Pacific
                                       (Biogeographic realm) Western Indo-Pacific
                                         (Biogeographic province) Somali/Arabian
                                           1 (Marine ecoregion) Arabian (Persian) Gulf
                                           2 (Marine ecoregion) Gulf of Oman
                                           3 (Marine ecoregion) Western Arabian Sea
                                           4 (Marine ecoregion) Central Somali Coast