Typhlopidae

Broadley, Donald G. & Wallach, Van, 2009, 2255, Zootaxa 2255, pp. 1-100 : 76

Key to the genera of Typhlopidae in eastern and southern Africa

1a. Third supralabial overlaps ocular shield (SIP T-III or T-V); dorsal rostral narrow to moderate (less than 1/2 interocular head width); nostril pierced laterally; postoculars 1–2; inferior nasal suture contacts second supralabial or preocular .......................................................................................................................................................................... 2

1b. Third supralabial not overlapping ocular shield (SIP T-II or T-X); dorsal rostral broad (greater than 1/2 interocular head width); nostril pierced ventrally; postoculars 3–7; inferior nasal suture contacts first supralabial or rostral..... 3

2a. Inferior nasal suture contacts preocular; dorsal rostral narrow (less than 1/3 interocular head width); postnasal bor- der not concave............................................................................................................... Ramphotyphlops ( braminus )

2b. Inferior nasal suture contacts second supralabial; dorsal rostral moderate (1/3–1/2 interocular head width); postnasal border concave ........................................................................................................................................... Typhlops

3a. Dorsal rostral very broad (greater than 3/4 interocular head width); eye usually absent, when present reduced to a pigmented spot; ocular reduced, smaller than or subequal to preocular; high middorsal count (22 species means = 355–684); size moderate and gracile (L/W = 45–130); dorsum usually unpigmented ................................................. ................................................................................................................ Letheobia (see Broadley & Wallach, 2007b)

3b. Dorsal rostral broad (1/2–3/4 interocular head width); eye well developed with visible pupil; ocular at least twice the size of preocular; moderate middorsal count (23 species means = 260–514); size large and robust (L/W = 20– 60); dorsum pigmented ............................................................................................................................................... 4

4a. Snout more or less rounded in profile, lacking a keratinized edge; ventral rostral narrow to moderate (less than 1/2 internarial snout width) .............................................................................................................................. Afrotyphlops

4b. Snout sharply angular in profile, with a keratinized horizontal edge in adults; ventral rostral broad (greater than 1/2 internarial snout width)................................................................................................................................................ 5

5a. Midbody scale rows 30–44, number decreasing anteriorly and usually reduced by 4 or more caudally; average length/width ratio <35; maximum length 540–950 mm ........................................................................ Megatyphlops

5b. Midbody scale rows 22–30, number increasing anteriorly and usually reduced by not more than 2 caudally; average length/width ratio> 40; maximum length 220–355 mm ....................................................................... Rhinotyphlops