Fk. Mckinney, A FASTER-PACED WORLD - CONTRASTS IN BIOVOLUME AND LIFE-PROCESS RATES IN CYCLOSTOME (CLASS STENOLAEMATA) AND CHEILOSTOME (CLASS GYMNOLAEMATA) BRYOZOANS, Paleobiology, 19(3), 1993, pp. 335-351
Zooids of cheilostome bryozoans are on average substantially more robu
st than are zooids of cyclostome bryozoans. The differences include gr
eater number, length, and cross-sectional area of tentacles, plus a mo
re extensively developed funiculus. Median values for mouth size and c
ilia-generated feeding current velocity are greater for cheilostomes t
han for cyclostomes so that cheilostomes have the potential for greate
r intake of nutrient energy per unit time, which may explain their app
arently higher growth rates. For unit area of substrate occupied, the
Cheilostomata (Class Gymnolaemata; members of the post-Paleozoic fauna
) contain greater biomass and apparently generate greater energy flow
than do the Cyclostomata, which are the only extant order of the Class
Stenolaemata (characteristic of the Paleozoic fauna).