Length of anterior chamber of gas bladder is the distance between the most anterior point 

 to the most posterior point of the anterior chamber. 



Length of posterior chamber of gas bladder is the distance between the most anterior point 

 to the most posterior point of the posterior chamber. 



Mouth angle is the angle between the dorsal surface of the head and a plane along the 

 dorsal margin of the lower jaw. 



2. Counts 



All counts (e.g., branchiostegal rays, fin-rays) were conducted with a Wild Microscope or 

 a Zeiss Microscope. The methods for different counts are described as follows: 

 Number of rays of paired fins were counted following Hubbs & Lagler (1947, 1964). 

 Number of rays of the dorsal and anal fins consists of procurrent rays (rudimentary un- 

 branched and unsegmented rays) and principal rays of Hubbs & Lagler (1947, 1964). 

 Hereafter the principal rays are referred to "rays". All procurrent rays and rays are coun- 

 ted. Caudal fin-rays were counted as dorsal and ventral procurrent, and dorsal and ven- 

 tral principal rays. 



All lateral line scales were counted. Cephalic lateral line pores were divided into six sec- 

 tions following Reno (1969), except the preoperculomandibular canal which is divided in- 

 to two sections (mandibular and preopercular sections) in the species of Phoxinus (see 

 below). All pores in each section were counted. 



Following Chen (1988b) and Chen & Arratia (1994), all primary lamellae were counted 

 as the total number of the primary lamella for each olfactory organ. No secondary la- 

 mellae are present on the primary lamellae in Phoxinus. 



Number of gill rakers on the first gill arch were counted and considered as the number 

 of gill rakers of the specimen. 



Number of vertebrae includes all vertebrae (from vertebra 1 to preural vertebra 1, ural 

 centra not included), and are divided into precaudal and caudal ones, according to May- 

 den (1989). The four vertebrae associated with the Weberian apparatus were counted as 

 four and included in the number of precaudal vertebrae. The count of vertebrae was made 

 on cleared and double stained specimens and some radiographs. 



3. Non-osteological and osteological morphology 



Non-osteological morphology was studied from 75% alcohol preserved specimens with 

 the microscopes mentioned above. Tubercles and scales were studied also with Scanning 

 Electron Microscope (SEM). 



Osteological features were studied on cleared and double stained specimens prepared fol- 

 lowing Dingerkus & Uhler (1977), and from radiographs of some specimens. 

 All measurements, counts, and non-osteological data were obtained from more than five 

 specimens for most species studied. In most cases, more than 15 specimens for each spe- 

 cies were studied. Whenever possible, more than three specimens of each species were 

 studied in order to collect the osteological data. In most Phoxinus species, a series of dif- 

 ferent sex and size was studied. 



