FIGURE 2 in A new species of Stegonotus (Serpentes: Colubridae) from the remnant coastal forests of southern Timor-Leste

FIGURE 2. Schematic dorsal head views of USNM 580549, the holotype of Stegonotus nancuro sp. nov., shown to illustrate the pattern of head scales and other important characters. Scale labels in (A) include internasals (IN), internasal suture (InS – distance between Points 1 and 2), prefrontals (PF), prefrontal suture (PfS – distance between Points 3 and 4), frontal (F), frontal length (FL – distance between Points 4 and 5), frontal width (FW), supraoculars (SO), postoculars (PO), parietals (P), external skull length (ESL – distance between Points 3 and 8), and parietal suture (ParS – distance between Points 5 and 8). The numbers 1–8 in (B) represent key reference points for measurements and angles as follows: (1) anteriormost internasal contact point; (2) posteriormost internasal contact point; (3) anteriormost prefrontal contact point; (4) posteriormost prefrontal contact point and anteriormost point on the frontal; (5) point on the frontal, where the posterior edge of the frontal meets the parietal suture; (6) the two points on either side of the head where frontal, parietal, and supraocular meet; (7) the two points on either side of the head where parietal, supraocular, and postocular meet; and (8) posteriormost parietal contact point. The posterior frontal angle (PF∠) is produced by a vertex at Point 5 with rays extending from Point 5 through Point 6 on either side of the head. The anterior parietal angle (AP∠) is produced by a vertex at Point 6 and two rays, one extending from Point 6 through Point 5 and the other from Point 6 through Point 7. The ray including Points 6 and 7 is the lateral ray, and its orientation relative to the midline of the head is of diagnostic value. The yellow line in (B) shows our method of evaluating the lateral ray, which can be oriented laterally (angle of the yellow line with the midline of the head = 90° ± 10°) or posterolaterally (the angle of the red line with the midline of the head <80°). The white anterior eye line (AE) intersects the anteriormost points of the eyes and is assessed by its position in relation to the anterior frontal suture ("behind," "same level," or "in front of").