98806
The most common organism , " Marrella " , was clearly an arthropod , but not a member of any known arthropod class .
 Marrella, arthropod
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 Marrella, arthropod