Morphology of pectoral girdle in Pomatoschistus lozanoi De Buen, 1923 (Gobiidae), in relation to pectoral fin adduction.

Like most gobies, Pomatoschistus lozanoi is a benthic fish species. During locomotion the pectoral fin adduction is of great importance in generating a forward propulsion. Several specimens of Pomatoschistus lozanoi were dissected, cleared with staining and sectioned with staining, in order to examine the morphology of the pectoral girdle-apparatus. In this paper a detailed description is given of the skeletal elements, the musculature and the ligaments of the pectoral girdle-apparatus. The pectoral fins of gobies seem better adapted to powerful adduction than a generalised teleost. The proximal radials form a large rigid shoulder plate with a long distal margin on which a high pectoral fin articulates. The fin muscles are strongly developed and assure, together with the large pectoral fin, powerful - drag based - pectoral propulsion. The morphological adaptations for powerful adduction, however, are at cost of the maneuvering abilities of the pectoral fins.