466 PROCEEOIIv GS OF. THE NATIONAL MUSEUM vol. loi 



were made for the University of Illinois to retain one of the two 

 paratypes of Hyla milleri described in this paper, and for permission 

 to study the material. 



Genus AMBYSTOMA Tschudi 



AMBYSTOMA ROSACEUM NIGRUM, new subspecies 



Figure 91 



Holotype.—U.S.'^M. No. 123581, larva; collected by Ralph G. 

 Miller on an indeterminate date. 



Tyjje locality. — El Salto, Durango. 



Diagnosis. — A large neotenic salamander characterized by a black 

 ground color with yellow markings ; by the presence of black ventral 

 bands; by a short leg (toes of extended leg do not closely approach 

 adpressed elbow) ; and by a pedal phalangeal formula of 2-2-3-3-2. 



Descri'ption. — Dorsal fin originating on back (23 mm. from snout), 

 at same level as point of origin of anterior limbs ; fin elevated 3.5 mm. 

 at level of hind limbs, and 4.5 mm. at base of tail; gill rakers on 

 middle arch 22 in number. Vomerine teeth in curved patches sepa- 

 rated by a distance less than a third their lengths, about 33 in number 

 and as many as 4 in a transverse row; 34 maxillary-premaxillary 

 teeth; 48-52 splenial teeth, arranged in two rows posteriorly; 10 

 pterygoid teeth; 11 costal grooves not counting slight auxiliary 

 grooves over axilla and groin ; phalangeal formula of hand 2-2-3-2, 

 of foot 2-2-3-3-2; webbing not reaching distal ends of metacarpals 

 or metatarsals (i. e., base of digits includes terminal portions of meta- 

 carpals) ; at least 5-mm. space between adpressed leg and elbow. 



The light ground color of Taylor's (1941) specimens of rosaceum 

 is so largely replaced by black markings that an actual reversal of 

 color pattern is apparent, nigrum showing a black ground color with 

 yellow (in alcohol) markings. The top of the head is black with 

 indistinct light reticulations; yellow on body limited to indistinct 

 longitudinal bands, which tend to break up into spots; tail mottled 

 with widely separated, irregularly shaped light blotches ; caudal fins 

 translucent and heavily mottled with black; limbs yellow-mottled; 

 belly yellow, marked by two long, wide lateral bands of black which 

 are separated from black of sides by broken lateroventral yellow 

 bands. 



Measurements of holotype in millimeters. — Total length 110; body 

 length 59; tail length 51; length of snout 5; eye width 3; snout to 

 arm insertion 19. 



Remarks. — Although no intergradation area has been demonstrated 

 between nigrwm and the more northern rosacewm., nigrum is here inter- 

 preted as being of subspecific rank. The pattern type is essentially 



