. Bulletin of the Natural History Museum Zoology. 124 O. RIEPPEL AND H. ZAHER. Fig. 1 The skull and mandible of Pseudotyphlops philippinus (BMNH ) in left lateral view. GENERAL ASPECTS OF THE SKULL The premaxilla of uropeltines is characterized by a single premaxil- lary foramen (Fig. 2). The vomerine processes of the premaxilla meet the vomer in a well-defined contact. The premaxilla of uropeltines shows characteristic variation within the group (Rieppel 1977; Cundall & Rossman 1993). The anterior margin of its trans- verse process is more or less evenly rounded in Melanophidiwn,
. Bulletin of the Natural History Museum Zoology. 124 O. RIEPPEL AND H. ZAHER. Fig. 1 The skull and mandible of Pseudotyphlops philippinus (BMNH ) in left lateral view. GENERAL ASPECTS OF THE SKULL The premaxilla of uropeltines is characterized by a single premaxil- lary foramen (Fig. 2). The vomerine processes of the premaxilla meet the vomer in a well-defined contact. The premaxilla of uropeltines shows characteristic variation within the group (Rieppel 1977; Cundall & Rossman 1993). The anterior margin of its trans- verse process is more or less evenly rounded in Melanophidiwn, which correlates with a gentle anteromedial curvature of the anterior end of the maxilla (Fig. 2A). The two bones closely approach each other, or barely establish contact. This genus therefore retains a plesiomorphic configuration of the snout, which is also inferred to be present in Platyplecturus (the specimen BMNH lacks the premaxilla, but retains the maxilla which shows an anteromedially curved anterior end), and which represents a con- dition similar to that seen in Anomochilus (Cundall & Rossman 1993). The other uropeltines have a similar premaxilla, which carries an anteriorly projecting, bipartite rostrum. The straight 'trans- verse' processes point posterolaterally, and meet the straight maxilla in a shizarthrosis (Cundall & Rossman 1993; Fig. 2B-E). These two elements define the lateral margins of the strongly 'telescoped' (Haas 1930), , tapering and pointed snout (see also Cundall & Rossman 1993, Fig. 25B). The maxilla of basal alethinophidians carries an anterior medial process (Rieppel 1977; Scanlon & Lee 2000), which is particularly well developed in uropeltines, where it participates in the formation of a broadly overlapping contact between maxilla, premaxilla, and vomer. In Melanophidiwn, the anterior medial process of the maxilla is not engaged in any such contact, but freely underlaps the septomaxilla. In Pseudotyphlops, the a
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