BREEDING TUBERCLES IN FISHES — COLLETTE 587 



the genital papilla, 0-2 rows above each side of the anal fm base, and 

 onto 3 ventral caudal peduncle scale rows. This collection matches 

 the description of the northern populations of E. stigmaeum more 

 closely than the southern ones. 



In studying the breeding behavior of Kentucky and Tennessee 

 populations oiE. stigmaeum, Winn (1958b, p. 172) found that males are 

 larger than females and have larger anal and pelvic fins. He reported 

 the presence of tubercles on the anal and pelvic fins of males but 

 failed to find any on the ventral body scales. Cross and Minckley 

 (1958) described the coloration of breeding males and noted tubercles 

 on the anal fin rays. In spawning, the male mounts the female in 

 such a manner that his tuberculate pelvic fins are in contact with her 

 dorsum and his tuberculate anal fin and ventral scales are in contact 

 with her sides (Winn, 1958a; 1958b, fig. 4). This spawning position 

 is similar to that found in a number of other darters such as E. 

 (Oligocephalus) caeruleum and E. (0.) spectabile and is totally unlike 

 the complex inverted spawning position of the nigrum species group 

 of Boleosoma. Winn (1958b, p. 188) felt that the placement of 

 stigmaeum in Boleosoma should be reconsidered. 



Subgenus loa Jordan and Evermann 



The only known species is E. vitreum (Cope). Specimens taken 

 from March 28 to May 17 (CU, UMMZ) lack tubercles. The males 

 are larger than the females and become much darker in the breeding 

 season, especially on the cheeks and venter. The genital papilla of the 

 breeding female has many free fleshy \illi. Winn and Picciolo (1960) 

 noted the pigment differences between the sexes and did not mention 

 the presence of breeding tubercles. They reported that E. vitreum 

 spawns communally in mid-April on a solid surface in the path of a 

 strong current. This behavior may have evolved from spawning 

 under rocks practiced by some members of the subgenus Boleosoma. 

 Winn and Picciolo listed several similarities between E. vitreum and 

 E. nigrum in support of this hypothesis: the sexes are beside each 

 other during spawning; one egg is laid at a time on a hard surface; 

 males are very black in the breeding season; and females of both 

 species have a complicated flowerlike genital papilla. The lack of 

 breeding tubercles in loa and the E. (Boleosoma) nigrum species group 

 further confirms this relationship. 



Subgenus Etheostoma Rafinesque 



Fifteen species are presently placed in this subgenus. The sub- 

 genus can be divided into two different tuberculate species groups and 

 one nontuberculate group. Members of the variatum group, variatum 



