128 



O. RIEPPEL AND H. ZAHER 



pterygoid in Melanophidium (Fig. 6A-B ) and Pseudotyphlops (Fig. 

 6C), a surface that is 'rounded off to a variable degree in smaller 

 species, and reduced in Rhinophis drumrnondhayi (Fig. 6E). By the 

 fact that the braincase elements remain separate in Melanophidium, 

 it is possible to ascertain that the prootic, opisthotic-exoccipital, and 

 basioccipital contribute to this enlarged posteroventral part of the 

 crista circumfenestralis. In the plesiomorphic condition, the 

 juxtastapedial recess is wide open laterally (Cylindrophis, 

 Anomochilus: Cundall & Rossman 1993), and such is also the case 

 in Melanophidium (Fig. 6A-B), Platyplecturus and Teretrurus. In 

 other uropeltines, the lateral opening of the juxtastapedial recess is 

 closed to a narrow slit, most extremely so in Uropeltis (Fig. 6D) and 

 Rhinophis (Fig. 6E-F), where the dorsal and ventral lips of the crista 

 circumfenestralis closely approach each other, or may even estab- 

 lish a restricted contact with each other. Never is the juxtastapedial 

 recess fully closed laterally, however, as is the case in Liotyphlops 

 (Haas 1964), typhlopids and leptotyphlopids (Rieppel 1979b). The 

 jugular foramen is internally subdivided in most uropeltines (except 

 in Pseudotyphlops, Teretrurus and Uropeltis), and it is located either 

 behind the juxtastapedial recess (plesiomorphic), or in the 

 posteroventral corner of the latter (in Platyplecturus, Plecturus, 

 Teretrurus and Uropeltis). The exoccipital is pierced by two hy- 

 poglossal foramina in Melanophidium punetatum (Fig. 6A), but by 

 a single, enlarged hypoglossal foramen in the other taxa investi- 

 gated. 



PHYLOGENETIC INTERRELATIONSHIPS 



Recent cladistic analyses hypothesized that Anomochilus is the 

 sister-group of uropeltines (Scanlon & Lee 2000; Tchernov et al. 

 2000), and Cylindrophis is the sister-group of uropeltines plus 

 Anomochilus (Tchernov et al. 2000; see also McDowell 1987; 

 Cundall et al. 1993, osteological data only). The addition of soft 

 anatomy characters by Cundall et al (1993) resulted in a different 



t J 



/ / i / ./ 



i k 



f / / / / > / / / 



f $ 



/ / / / / / / / / 

 / / / / / it 



Table 1. The data matrix used in the analysis of the phylogenetic 

 interrelationships of Uropeltinae. Character definitions are given in 

 Appendix I. 



12345 67891 11111 11112 22222 22223 333 

 12345 67890 12345 67890 123 



Melanoph. punetatum 



00000 



01000 



00000 



00022 



11111 



11111 



111 



Melanoph. wynaud. 



00100 



00000 



1 



00111 



1 



20111 



00000 



10022 



11111 



11111 



111 



Platyplecturus 



01100 



12011 



10122 



11111 



11121 



111 



Uropeltis 



11111 



12110 



11222 



11111 



11121 



111 



Teretrurus 



10100 



11110 



12001 



10222 



urn 



11121 



111 



Rhinophis drum. 



11111 



mil 



12110 



11222 



mil 



11121 



111 



Rhinophis sang. 



11111 



20111 



11110 



11?22 



urn 



11121 



111 



Plecturus 



11101 



00111 



1 



01111 



12110 



11122 



inn 



11121 



111 



Plseudotyphlops 



11100 



01101 



11222 



inn 



11121 



111 



Anomochilus 



00100 



01000 



0000? 



00011 



mil 



11120 



000 



Cylindrophis 



00000 



00000 



1 



00000 



00000 



1 



00000 



00010 



00001 



11110 



000 



Anilius 



00000 



00000 



00000 



00010 



000 



Fig. 7 The phylogenetic interrelationships of Uropeltinae. See text for 

 further discussion. 



cladogram, which still reproduces the monophyly of Alethinophidia 

 and Macrostomata respectively, but which shows anilioids (Rieppel 

 1977, 1988) to be paraphyletic. The sound transmitting apparatus 

 was found to be 'similar' in Typhlops and Rhinophis by Wever 

 ( 1978: 705), but a sister-group relationship of scolecophidians and 

 uropeltines has so far never been recovered through cladistic analy- 

 sis of morphological data (Cundall et al. 1993;Kluge, 1991;Scanlon 

 and Lee 2000; Tchernov et al. 2000), and it was specifically rejected 

 by Cadle et al. (1990; see also Cundall & Rossman 1993). 



Previous work (Tchernov et al. 2000), and the description of the 

 uropeltine skull presented above, allows the delimitation of 33 

 phylogenetically potentially informative characters (Appendix I 

 and Table 1 ) for an analysis of uropeltine interrelationships. Given 

 the currently controversial relationships of Anilius and Anomochilus 

 relative to uropeltines, these two taxa together with Cylindrophis 

 were used as paraphyletic outgroup in the analysis of uropeltine in- 

 group relationships (characters 25 through 28 are uninformative 

 using this rooting procedure, and were ignored in the analysis). The 

 analysis was performed using PAUP version 3.1.1. (Swofford 1991. 

 Swofford & Begle 1993). All multistate characters were unordered, 

 and the branch-and-bound search option was implemented. Character 

 optimization is based on the DELTRAN routine. 



A single most parsimonious tree was obtained (TL = 49; CI = 

 0.796; RI = 0.877) with fully resolved uropeltine relationships. 

 Given the scarcity of characters, it is not surprising that some nodes 

 among uropeltines are rather poorly supported (with the minimal 

 decay index or Bremer support index [Bremer 1 988] : + 1 ). Neverthe- 

 less, the tree (Fig. 7) suggests some interesting preliminary results. 



The basal position of Melanophidium among uropeltines was 

 expected (Rieppel 1977; McDowell 1987), and is reproduced here. 

 However, there is a signal for paraphyly of the genus Melanophidium. 

 Melanophidium wynaudense appears to be more closely related to 

 other uropeltines than it is to Melanophidium punetatum (decay 

 index: +1) on the basis of the presence of a single (enlarged) 

 hypoglossal foramen behind the jugular foramen ( 16[1] ; ci=l). 

 Evidently, the monophyly of the genus Melanophidium must be 

 tested by the addition of other characters, including soft anatomy, 

 because the result obtained here may be nothing more than the 

 reflection of the fact that as coded, Melanophidium punetatum is 

 plesiomorphic relative to all other uropeltines in all characters that 



