|Title||Breeding tubercles of Phoxinus (Teleostei: Cyprinidae): Morphology, distribution, and phylogenetic implications|
|Publication Type||Journal Article|
|Year of Publication||1996|
|Authors||Chen X-Y, Arratia GF|
|Journal||Journal of Morphology|
|Keywords||Anatomy and Histology - Comparative anatomy 11108, Anatomy and Histology - Microscopic and ultramicroscopic anatomy 16502, Chordata: general and systematic - Pisces, Cytology - Animal 11103, Evolution 02506, Osteichthyes  Reproduction Cell Biology Evolution and Adaptation Morphology Reproductive System Systematics and Taxonomy Pisces Vertebrata Chordata Animalia 01500, Reproductive system - Anatomy 62510|
Studies of the skin with scanning electron microscopy (SEM) reveal a diverse morphology in breeding tubercles among species of Phoxinus. Based mainly on the fine structure of the surface of tubercles, nine morphotypes, coded as letters A-I, occur in Phoxinus. Most of the morphotypes are common to all Phoxinus species, but type E is present only on the dorsum of the head of P. phoxinus, type H on the breast scale of female P. phoxinus, and type I on the pectoral fin in P. erythrogaster. Multicellular breeding tubercles bearing unicellular projections, identified as unculiferous tubercles are found in type H and probably types F and G. The distribution of tubercles on head, body, and fins is described and compared among Phoxinus species. Breeding tubercles in Phoxinus and other minnow genera are compared in order to interpret the phylogenetic implication of the tuberculation in Phoxinus. The deeply embedded breast scales and the breeding tubercles on their apical margins, and a series of tubercles on the apical margins of lateral scales of the caudal peduncle in breeding males of Phoxinus species, are the characters supporting the monophyly of the genus.