Oxybelis vittatus (Girald 1854)

Jadin, Robert C., Blair, Christopher, Orlofske, Sarah A., Jowers, Michael J., Rivas, Gilson A., Vitt, Laurie J., Ray, Julie M., Smith, Eric N. & Murphy, John C., 2020, Not withering on the evolutionary vine: systematic revision of the Brown Vine Snake (Reptilia: Squamata: Oxybelis) from its northern distribution, Organisms Diversity & Evolution (New York, N. Y.) 20 (4), pp. 723-746 : 741-742

Oxybelis vittatus (Girald 1854)

Striped Vine Snake

Dryinus aeneus – Wagler 1824: 12

Dryophis vittatus – Girard 1854: 226

Oxybelis aeneus auratus – Bogert and Oliver 1945: 381 Oxybelis aeneus – Keiser 1974: 7

Holotype USNM 7315 from Taboga Island , Bay of Panama, Panama. Girard (1854) reports the holotype has 193 ventral scales and 165 plus subcaudal scales (the tail is broken).

Diagnosis Using data from our examination of specimens from Panama, we constructed the following description for Oxybelis vittatus . A vine snake with (1) three upper labials (4–5–6) bordering the orbit; (2) transverse black bars or spots on the anterior body; (3) a pale, indistinct stripe on the mid-ventral, and black mottling; (4) eye diameter greater than length of preocular; (5) second pair of chin shields in contact for most of their length; (6) eight upper labials, three behind the orbit; (7) from above the snout is tapered and terminally rounded (snout type A); (8) supraoculars longer than the prefrontals; (9) last upper labial longer than primary temporal; (10) lower surface of head uniform and pale; and (11) second upper labial does not contact the preocular ( Fig. 15 ) .

Variation Rostral is barely visible from above and followed by nine plate-like scales on the crown: a pair of internasals, a pair of prefrontals, the frontal and two larger supraoculars, and a pair of parietals. Preoculars extend slightly on to the crown between the prefrontals and supraoculars. In profile, the nasal scale is elongate extending from the edge of the rostral, beyond the posterior edge of the internasal to the anterior border of the fused prefrontal–loreal. Preocular scale is long and greater in length than the diameter of the eye. The eye diameter/internasal ratio in this species averages 1.16 (n = 9, r = 1.05–1.31, SD = 0.17). Scales bordering the orbit are the preocular, the supraocular, two postoculars (the upper one is usually the largest), and upper labials 4–5–6. The primary temporal contacts both postoculars, the parietal, two secondary temporals, and upper labials 5–6–7–8, 6–7–8, or 6–7–8–9 are common arrangements. Upper labials range from 8 to 10. Of 20 sides examined, 13 (65%) had 8 upper labials, six (30%) sides had 9 upper labials, and one side (0.05%) had 10 upper labials. The shortest upper labial can be the fourth or the fifth. The longest upper labial is the last eight, nine, or ten. Upper labials 1–2 contact the nasal, 2–3 contact the prefrontal–loreal, and 3–4 contact the preocular. The tallest upper labial can be the sixth or seventh. Lower labials range from 7 to 9 (usually 8 or 9). The first four (rarely five) contact the anterior chin shields; a total of six contact both pair of chin shields.

In males, total lengths vary from 1149 to 1323 mm (n = 2, x = 1236.0 SD = 87.00), SVL varies from 653 to 763 mm (n = 2, x = 708, SD = 55.00), tail lengths vary from 460 to 560 mm (n = 2, x = 505.33, SD = 41.35), and tail/SVL ratios vary from 0.73 to 0.76 (n = 2, x = 0.74, SD = 0.01). In females, total lengths vary from 940 to 1345 mm (n = 7, x = 1138.57, SD = 128.85), SVL varies from 510 to 832 (n = 7, x = 670 mm, SD = 95.53), and tails vary from 410 to 518 mm (n = 7, x = 505.33, SD = 41.35). Tail/SVL ratios in females vary from 0.62 to 0.84 (x = 0.74, SD = 0.01).

Ventrals in males vary from 179 to 187 (n = 5, x = 183.4, SD = 3.38); ventrals in females vary from 182 to 193 (n = 7, x = 186.83, SD = 4.02. Subcaudals not counted because of damaged tails.

Coloration and pattern The crown of the head and upper face are brown to tan; they may be uniform or slightly mottled. Upper labials and ventral surface of the head are a uniform cream. The transition in color is separated by a preocular dark-brown stripe extending from the nasal scale, under the eye, and onto the anterior body. This stripe may continue as a series of spots onto the body. On the anterior body, the first two scale rows are the same yellow color as the ventral surface, and form a ventrolateral stripe. At mid-body, the first four dorsal scale rows and the lower half of the fifth scale row have a dark pigment streak in the middle of the scale giving the impression of a faint stripe on each scale row; scale rows 6–8 lack the dark pigmentation. The ventral surface is often flecked with dark pigment and indistinct lateral stripes on the edges of the ventrals.

Geographic distribution Panama likely southward into the Chocoan region of Colombia

Comparison A brown vine snake with eight upper labials, two behind the orbit, and the fifth is the shortest; the second pair of chin shields are in contact for most of their length, and the primary temporal is shorter than the last upper labial. Oxybelis aeneus and O. rutherfordi have the second pair of chin shields separated; O. koehleri and O. microphthalmus usually have three upper labials behind the orbit, and the last upper labial is equal to the length of the primary temporal.

Figures

Fig. 15 Oxybelis vittatus. FMNH 170133, from the Canal Zone of Panama. a Profile; b crown; c underside of head