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D.J. GOWER AND M. WILKINSON 



>J 



Fig. 8 Uraeotyphlus cf. narayani (UMMZ 139810). Cloaca of immature male, prepared as specimen shown in Fig. 6. Scale = 2 mm. 



with many groups of caecilians, the taxonomy of Uraeotyphlus has 

 an inadequate basis, with some species known from only few 

 specimens, many with poor locality data. Few diagnostic characters 

 have been identified and current keys are not satisfactory, so that 

 caution needs to be exercised in applying names to individuals, and 

 in assuming species identity of groups of individuals. The following 

 discussion draws on the examination of the cloaca in more than 30 

 male Uraeotyphlus representing at least three distinct species. The 

 focus here is on features of the lumenal surface of the anterior 

 portion of the phallodeum, chiefly the longitudinal ridges and their 

 ornamentation. 



Figures 4 to 8 show the morphology of the phallus and dissected 

 cloacae of four specimens. These are identified as Uraeotyphlus cf. 

 narayani Seshachar, 1 939, but unpublished morphological and mole- 

 cular data have revealed previously unsuspected diversity in the 

 populations that these individuals are drawn from. It is not yet 

 apparent whether this diversity is indicative of previously unrecog- 

 nised specific or subspecific taxa. Whatever their true specific 

 identity, these four specimens share a common pattern in the major 

 features of the anterior phallodeum. There are seven major longitu- 

 dinal phallodeal ridges - a single mid-dorsal ridge, and pairs of 

 dorsolateral, lateral, and ventrolateral ridges. As in most other 

 caecilians, the anterior end of each dorsolateral ridge holds a major 

 longitudinal sulcus that extends into the corresponding blind sac 

 (Figs. 4, 5, 9). In mature individuals, each of the major longitudinal 

 ridges bear hardened transverse thickenings. When relatively small, 

 these thickenings bear an approximately transverse narrow line of 

 dense, opaque tissue that stands out against the more translucent 

 main body of longitudinal ridge. Where relatively large, the 

 thickenings are developed into tuberosities that can be irregular, and 

 that interlock in the uneverted cloaca. The mid-dorsal ridge bears 

 three such tuberosities and the other, paired longitudinal ridges two 

 each. The transverse thickenings of each major longitudinal ridge 

 are offset relative to each adjacent ridge, and they generally bear the 

 same spatial relationship to each other in each individual (Figs. 4 to 

 7). Of the paired ridges, the lateral ones are the least well developed, 



and sometimes they are best located by their transverse thickenings. 

 Within this common pattern are some minor variations. In immature 

 males (Fig. 8), the main longitudinal ridges are less well developed 

 and bear no transverse thickenings or indications of hardened tissue, 

 but they can still be readily identified and homologised with those in 

 mature males. In addition, the blind sacs of immature males are not 

 developed. Instead, there is a pair of shallow pits in their place. The 

 relative size of the transverse thickenings or tuberosities also varies 



Fig. 9 Uraeotyphlus cf. oxyurus (field tag MW 469). Cloaca of mature 

 male prepared as specimen shown in Fig. 6. The incision has 

 longitudinally bisected the left ventrolateral longitudinal ridge so that 

 parts of it lie on each side of the opened cloaca. The left side of the 

 posterior end of the urodeum has been torn away from the anterior end 

 of the phallodeum so that retractor muscle is visible through the 

 resulting hole. Scale = 3 mm. 



