New paper by Marc Herbin and colleagues published in Nature Communications.

Allometric growth in the extant coelacanth lung during ontogenetic development

Coelacanths are lobe-finned fishes known from the Devonian to Recent that were long
considered extinct, until the discovery of two living species in deep marine waters of the
Mozambique Channel and Sulawesi. Despite extensive studies, the pulmonary system of
extant coelacanths has not been fully investigated. Here we confirm the presence of a lung
and discuss its allometric growth in Latimeria chalumnae, based on a unique ontogenetic
series. Our results demonstrate the presence of a potentially functional, well-developed lung
in the earliest known coelacanth embryo, and its arrested growth at later ontogenetic stages,
when the lung is clearly vestigial. The parallel development of a fatty organ for buoyancy
control suggests a unique adaptation to deep-water environments. Furthermore, we provide
the first evidence for the presence of small, hard, flexible plates around the lung in
L. chalumnae, and consider them homologous to the plates of the ‘calcified lung’ of fossil