4 University of Michigan 



Thyrina colombiensis, new species 



Holotype: Cat. No. 1387 1, Museum of Indiana University, 

 a specimen loi mm. long (without caudal) collected by Arthur 

 Henn and Charles Wilson ''from Barbacoas to 8 miles above," 

 in the Rio Telembi, a tributary of the Rio Patia, on the Pacific 

 slope of southern Colombia. The paratypes, varying in standard 

 length from 19 to 104 mm., comprise series from the type locality; 

 from Condoto, on the Rio Condoto, a tributary of the San Juan 

 (13870, I, U.); from the Rio San Juan at Istmina (13868, I. U.), 

 and at Tado, Colombia (13869, I. U.). A set of paratypes from 

 the Rio Telembi is deposited in the Museum of Zoology of the 

 University of Michigan (Cat. No. 55006). Three lots of specimens 

 of this new form are deposited in the Carnegie Museum (7485, 

 from Istmina ; 7486, from Condoto ; 7487, from the Rio 

 Telembi). 



Body with the form characteristic of Thyrina, a little more 

 compressed than in T. brasiliensis; greatest depth, 4.9 (4.6 to 

 4.9)^ in standard length; least depth of caudal peduncle about 

 equal to postorbital length of head, or to the interorbital width. 

 Length of head to angle of opercle, 4.4 (4.0 to 4.6); length of 

 orbit, 3.5 (3.1 to 3 .6). Snout a little longer than the orbit (orbit 

 longer than snout in young), its rather sharply pointed and pro- 

 jecting tip on the horizontal passing through upper edge of pupil. 

 Lower outer edge of mandible slightly concave, forming an angle 

 of 45° with the horizontal; upper edge of mandible horizontal 

 anteriorly and oblique but moderately elevated posteriorly (within 

 the mouth); maxillary extended backward to vertically below 

 front of posterior nostril. Teeth in rather narrow bands on the 

 jaws; the outer series of the premaxillary, projecting downward 

 from the edge of the lip, moderately enlarged; palate edentulous. 



* The measurements and counts in parentheses are those of twenty para- 

 types from the Rio Telembi, from Istmina and from Tado. 



