16 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 124 



the fossil Monophyllus may be distinguished by its rather longer rostrum and 

 noticeably longer toothrow. 



We have examined three fragments of M. frater, including two 

 rostra and one palate. As in other representatives of M. plethodon, 

 the diastema between the upper premolars is narrow; the first upper 

 premolar is lacking in the three fragments, but its alveolus and either 

 the alveolus of the second premolar or the tooth itself clearly demon- 

 strate that the two upper premolars were appressed as in the Lesser 

 Antillean M. plethodon. There is no question that M. frater is related 

 to M. plethodon rather than to the Greater Antillean M. redmani. 



We use a trinomial to show the close affiliations of M. frater with 

 M. plethodon. There are those who feel that such usage is inappro- 

 priate for nonsynchronous taxa. We do so here for three reasons: 

 (1) Although no large Monophyllus has been taken in the flesh on 

 Puerto Rico, there is a good possibility that M. p. frater may be so 

 encountered. Several other Antillean mammals (Brachyphylla nana 

 and Capromys nana in Cuba, and Brachyphylla pumila on the island 

 of Hispaniola) were named originally from fragmentary cave 

 material and were later secured in the flesh. (2) Monophyllus r. 

 portoricensis and M. p. frater were apparently at least partially con- 

 temporaneous in Puerto Rico, suggesting that the latter species is a 

 relatively recent inhabitant of the island rather than an ancient 

 arrival. Anthony (1918, p. 338), writing specifically about the Cueva 

 Catedral fossils, concluded that "the fossil bats of Cueva Catedral 

 have been fossil for no lengthy period" and that, considering the 

 Puerto Rican fossil fauna as a whole, a "conservative estimate would 

 place the island mammalia as living at the end of the late Pleistocene 

 and there is little doubt that this age may be extended into the 

 Recent." (3) Use of a trinomial clearly shows the close relationship 

 of M. frater with the other subspecies of M. plethodon. Maintaining 

 two distinct species obscures their obvious affinities. 



Anthony's (1918, p. 350) brief comparison of M. frater with M. 

 luciae (that the former differs from the latter in having a "rather 

 longer rostrum and noticeably longer tooth row") seems to be affirmed 

 by recently acquired specimens of M. p. luciae although, considering 

 the total variation in luciae, the differences are far from striking. 

 Anthony's measurements (1918, p. 350) of "interorbital breadth" 

 (4.6-4.9 in three M. frater) fall within the known variation of our 

 measurements of postorbital breadth in M. luciae (4.5-5.0) and 

 above those of M. redmani (3.8-4.6 in all subspecies, with M. r. 

 redmani most closely approaching the measurements of M. p. frater). 

 The alveolar length of the upper molariform series of two M. p. 

 frater measures 6.8 and 7.1, quite comparable to similar measure- 

 ments in other M. plethodon. It is even possible that M. p. frater is not 



