THE AMPHIBIA OF OKLAHOMA 



9. Microhyla c. caroUnensis (Holbrook). 



Cherokee (2), Le Flore (C), Mayes (T), McCurtain (1). 



The distribution of the two forms of Microhyla olivacea in Oklahoma 

 (olivacea and caroUnensis) has been uncertain till recently. I had supposed 

 only the former to be present (Bragg, 1943) till 1946 (Bragg, 1946). 

 Recently Hecht and Metalas (1946) relegate olivacea to a subspecies of caro- 

 Unensis partly on the basis of specimens of intergrading color pattern from 

 Latimer County, Oklahoma. They could find no structural characters other 

 than color pattern which consistently will separate the two forms. Because 

 of these uncertainties I have rechecked the specimens in the University of 

 Oklahoma Museum (Division of Zoology) from the state as well as making 

 special efifort to secure more information while in eastern Oklahoma during 

 the last two seasons. 



Of sixteen museum specimens from Latimer County, fourteen, identified 

 some years ago by Mrs. Helen P. Gaige as Microhyla caroUnensis, are clearly 

 of this form. Two appear to intergrade in ventral color pattern and a note with 

 one of these specimens indicates that possible intergradation with M. olivacea 

 was recognized by Mrs. Gaige. All specimens from McCurtain County are 

 caroUnensis and under favorable conditions for breeding in May, 1946, caro- 

 Unensis was the form exclusively seen and heard near Idabel. In Le Flore 

 County, this species was calling with the hylas northwest of Page (see above) 

 and without them at the same pool in the afternoon; but a specimen could 

 not be secured. Later in 1946, another small chorus was heard at dusk in a 

 spring-fed pool on the bank of Tyner Creek in eastern Cherokee County. 

 They were found calling at this same site in June, 1947, as well as elsewhere 

 in this general region. I have formerly heard olivacea in western Cherokee 

 County north of Fort Gibson. Since both forms are present at Fort Smith, 

 Arkansas (Bragg, 1946) the band of territory separating the two in Oklahoma 

 appears to follow closely that separating Bujo tvoodhoiisii fowleri and B. w. 

 woodhoHsii (Bragg and Smith, 1943). 



Some observations on the calls and slight differences in behavior of the 

 two forms seem worthy of record. On each of several recent occasions the 

 largest chorus of M. c. caroUnensis has developed on warm bright afternoons 

 with a lessening of the calls at night. With olivacea the reverse tends to be 

 the case in all my experience. The calls of the two are different, that of olivacea 

 appearing to me to be of slightly higher pitch and with greater carrying 

 power. To Wright and Wright (1942) the reverse seems to be true. Both 

 call from clumps of vegetation but males of caroUnensis, on the twelve occa- 

 sions when I have studied a chorus, invariably have called only from the 

 tallest and thickest grass clumps. Olivacea often uses such places but does 

 not invariably do so. This makes specimens of olivacea much easier to collect 

 by hand than those of caroUnensis. It will be interesting to observe these 

 matters in intergrades. 



10. Microhyla c. olivacea (Hallowcll). 



Jefferson (T), Okmulgee (I), Major (T). 



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