The gills of the coelacanth, Latimeria chalumnae Latimeriidae. What can they teach us?

The low surface area of Latimeria gills has been confirmed for a range of b ody sizes from 450 gr to 80 kg. This is an indication of an inactive mode o f life as has now been observed from submersibles. The gill septa indicate that Latimeria and lungfishes share an autapomorphy, presumably secondarily lost in tetrapods, since it is generally accepted that lungfishes and tetr apods are sister groups. The presence of a central venous sinus, arterio-ve nous anastomoses and other features of the secondary circulation suggest co elacanths are similar to other fish groups in which such structures are pre sent (i.e., Actinopterygii, Chondrichthyes). The absence of a secondary cir culation and existence of a type of lymphatic system suggests that Dipnoi a re more closely related to tetrapods than are coelacanths.