Osteological characters to define six species of the Capoeta damascina species complex (Cypriniformes: Cyprinidae)

Abstract

This paper presents the results of a comparative study of eight osteological characters: the counts, dimension and regionalization of the vertebral column, the pattern of interdigitation of the dorsal- and anal-fin pterygiophores with the neural and haemal spines of the vertebrae, the distribution of the dorsal- and ventral-procurrent caudal-fin rays, the distribution of the principal caudal-fin rays, and the morphology of the caudal-fin skeleton of six species of the Capoeta damascina complex (Cypriniformes: Cyprinidae). Potential taxonomically valuable osteological characters are described and used to separate the six species of Capoeta studied. Formulae for the structure of the vertebral column, the dorsal- and anal-fin pterygiophores’ interdigitation with the neural and haemal spines of the vertebrae, the distribution of the dorsal and ventral procurrent caudal-fin rays, and the distribution of the principal caudal-fin rays are developed. These morphological descriptive parameters express a morphotype that may be linked with the cypriniform mode of swimming of the Capoeta species investigated. The morphological study of the vertebral column of six species of the Capoeta damascina complex enables the division of this bony structure into five or six morphologically distinct regions, depending on the species, and the drawing of characteristic vertebral profiles. This regionalization is more complicated than the classical division in abdominal and caudal parts only.