199 



SCI1<]XT1FIC RESULTS FllOM THE :MAMMAL SURVEY 



No. XV] . 

 (.1) — TiiK TiPAiAs OK Soirrii Tknasskkim. 

 BY Oldfield Thomas. 



(^Piihlished hi/ permission of the Trustees of the British Museum.') 



A nice series of Tree Shrews from Pegu, topotypes of Tujxtia 

 hela7igeri, presented by jMr. J. M. D. Mackenzie, has enabled me 

 to investigate afresh the relationship of the southern members of 

 the T. helangeri group to the northern members of the ferruginea 

 group. 



When Dr. Lyon wrote his Monograph of the Tupaiida3 in 1913 

 the only modern examples of typical helangeri were two collected 

 near Rangoon by Major Harington, and these differ materially in 

 their degree of rufous on the posterior back, the one almost with- 

 out it, the other strongly rufous. 



Having to choose one of these as the more typical, Dr. Lyon 

 chose the rufous one, but Mr. Mackenzie's series now shoAvs that 

 the normal coloi'ation in this region is as in the other specimen, 

 without rufous on the iiamp. 



Further east in the IMoulraein region, and southwards as far as 

 Tenasserim town, similar forms occur, liut becoming more and 

 moi'e frequently rufous or ochraceous posteriorly. 



All these animals have a short snout to the skull, and have 

 three pairs of mammae, evenly spaced on the axillo-inguinal area. 



In the extreme south of Tenasserim, however, at Bankachon 

 (spelt by Davison Bankasun) the local form is much brighter and 

 more markedly red-rumped, and this seemerl at first to indicate a 

 local sub-species of helant/eri. Specimens of it collected by Davison 

 have long been known, and always considered as helangeri. 



But close examination shows the remarkable fact that while 

 these specimens have the general appearance, and (with the varia- 

 tion indicated below) the mammary formula of helangeri, they have 

 the longer skull of the North !Malay i-epresentative of the ferruginea 

 group, T. laceniata ivilkinsoni, whose type locality is Trang, about 

 180 miles south of Bankachon. 



This skull difference — and there is no other — seems slight when 

 isolated specimens are examined, but is so constant and with such 

 a complete absence of intermediate specimens that there seems no 

 doubt that the Tupaia of extreme S. Tenasserim is a distinct species 

 intercalated between helangeri to the north and lacerrnata to the 

 south. 



