Leptophis ahaetulla, Linnaeus, 1758

Albuquerque, Nelson Rufino De & Fernandes, Daniel S., 2022, Taxonomic revision of the parrot snake Leptophis ahaetulla (Serpentes, Colubridae), Zootaxa 5153 (1), pp. 1-69 : 9-11

Leptophis ahaetulla complex

Definition. Members of this complex are distinguished from other congeners by having the following combination of states of characters: usually no loreal scale; postocular black stripe never extending posteriorly onto the anterior third of the body; anterior portion of the body of adult specimens in life variable but never copper, silver-gray green or with tranverse dark bands; general color pattern ranges from unicolored to striped; two dorsolateral stripes on the anterior portion of the body separated by a vertebral stripe or a middorsal area clearly defined; anterior portion of the body of adult striped specimens never grayish gold to bronze or emerald green; dorsal scales with single apical pit (rarely two) on most scales; all dorsal scales keeled, except those on the first row of each side and occasionally on vertebral row; dorsals of tail may be keeled for most of the length of tail; and less than 33 maxillary teeth.

Distribution. Mexico, Central- and South America, including the Caribbean islands of Trinidad and Tobago ( Figs. 4 , 8 , 18 ).

Key to the species of Leptophis

Because of the pattern of oblique dark bands found in most juveniles, this key is mostly focused on the identification of adult specimens (see also diagnoses, comparisons and Table 2). In addition, we used the following references for species that are not part of the Leptophis ahaetulla complex: Oliver (1948), Hoyt (1964), Henderson (1976), Harding (1995), Savage (2002), Albuquerque & McDiarmid (2010), Murphy et al. (2018), and Torres-Carvajal et al. (2020). The subspecies of L. mexicanus Duméril, Bibron & Duméril are merely listed after their respective species. We used no characters with very large range values (e.g., number of ventrals and subcaudals) since they largely overlap between the different species of the Leptophis ahaetulla complex ( Table 2). Moreover, for at least two species ( L. bocourti and L. stimsoni ) known from only a few specimens, the key will probably not include all potential variation of these taxa. We use the term “usually” to describe conditions that exist in at least 95% of the specimens examined.

1. Loreal scale usually present............................................................................. 2 1.1. Loreal scale usually absent.............................................................................. 5

2. Keels usually present only on scales of paravertebral rows..................................................... 3

2.1 Keels usually present on all dorsal scales except for the first scale row........................................... 4

3. Preocular black stripe absent; a short, narrow postocular black stripe usually extending no farther than three scales posterior to last supralabial; usually 9 supralabials on each side; 33–36 maxillary teeth........................... L. depressirostris

3.1 Preocular black stripe present; a long, broad postocular black stripe continuing onto body anteriorly on rows III-VII; usually 8 supralabials on each side; 17–21 maxillary teeth................................................... L. diplotropis

4. Dorsal scales with no apical pits; dorsum uniform green (dark bluish-green in preservative); a short, narrow postocular black stripe usually extending along suture between supralabials-lower postocular and between supralabials-temporals.................................................................................................... L. modestus

4.1 Dorsal scales, except for the first row, with apical pits; dorsum with lateral stripe on rows II-V/VI, middorsal area between lateral stripes grayish gold to bronze or emerald green (light greenish blue, light greenish brown, greenish blue, light gray, or light brown in preservative); a long postocular stripe (reduced to temporal region in L. m. hoeversi and to the region of the neck in L. m. septentrionalis) continuing posteriorly onto the anterior third of the body................................................................ L. mexicanus (L. m. mexicanus , L. m. hoeversi, L. m. septentrionalis, L. m. yucatanensis)

5. Adults and juveniles with a series of transverse dark bands on dorsum; all dorsal scales keeled................... L. riveti

5.1 Adults usually lack a series of transverse dark bands on dorsum; no keels on first dorsal scale row..................... 6

6. Adult color pattern with two dorsolateral stripes covering scale rows II-III or II-IV on each side, at least in anterior portion of the body............................................................................................ 7

6.1 Adult color pattern with or with no two dorsolateral stripes; if present, stripes separated by a bright green (dark blue or blue gray in preservative) middorsal area three to nine dorsal scale rows wide, or stripes cover scale row II (at least anteriorly) and are yellowish (in life).................................................................................. 8

7. Adults with two Light Grass Green (109) to Light Emerald Green (142) (dark blue or greenish gray in preservative) dorsolateral stripes covering scale rows II-III (occasionally the IV) on each side, at least on anterior portion of the body; rows II–III (occasionally II–V) in anterior portion of the body Sulphur Yellow (80); before body scale reduction from 15 to 11, rows II–III usually suffused with Yellow Ocher (14); Jet Black (300) postocular stripe indistinct or narrow, occupying the lower edge of the anterior temporal, with lower edge to one-third of lower posterior temporal pigmented.................. L. ahaetulla

7.1 Adults with two Light Emerald Green (142) to Robin’s Egg Blue (161) (caribbean blue to venetian blue in preservative) dorsolateral stripes covering scale rows II–IV on each side, at least on anterior portion of the body; rows I–III in anterior portion of the body white to Pale Sulphur Yellow (92); before body scale reduction from 15 to 11, rows II–III not suffused with Yellow Ocher (14); Jet Black (300) postocular stripe wide, occupying the lower half or two-thirds of anterior temporal and most of the lower posterior temporal...................................................................... L. dibernardoi

8. Head and dorsum in adults predominantly copper (coppery tan in preserved specimens with stratum corneum or bluish with no stratum corneum), dorsal bands of living juveniles are shaded on outer edges with bright emerald green and are copper on inner edges, giving a coppery-green tinge to general color................................................... L. cupreus

8.1 Head and dorsum in adults not as above................................................................... 9

9. Dorsum silver-gray green, with a tan venter (dark green both dorsally and ventrally in preservative); dorsolateral stripe one scale wide on each side; dorsal scales of tail keeled for half of its length.................................. L. stimsoni

9.1 Dorsal and ventral color pattern not as above; if present, dorsolateral stripes two or more scales wide; most of dorsal scales of tail keeled or no keels on dorsal scales of tail.............................................................. 10

10. If present, dorsolateral stripes in anterior portion of the body separated by a bronze (light or light-gray in preservative) middorsal area two to three scale rows wide.................................................................. 11

10.1 Dorsolateral stripes on anterior portion of the body separated by a Light Grass Green (109) (dark blue or blue gray in preservative) middorsal area three to nine scale rows wide.............................................. L. coeruleodorsus

11. Adult pattern with no dorsolateral stripes on anterior portion of the body........................................ 12

11.1 Dorsolateral stripes on anterior portion of the body present, separated by a bronze (light-gray in preservative) middorsal area six-eight scales wide.......................................................................... L. nebulosus

12. Supracephalic scales and dorsum never marked with numerous small, irregularly shaped black spots.................. 13

12.1 Supracephalic scales and dorsum Dark Egg Blue (162) (dark slate gray or ultramarine in preservative), and marked with numerous small, irregularly shaped black spots (brown in preservative; dorsum not spotted in the single juvenile examined); supracephalic scales narrowly edged; black keels on paravertebral and vertebral rows more prominent; two median rows of dorsal scales on tail keeled for most of length of tail....................................................... L. bocourti

13. Supracephalic scales and dorsum uniformly Grass Green (110) (dark blue in preservative), supracephalic scales finely edged with black; interstitial skin on dorsolateral region with Sulphur Yellow (80) (white in preservative) chevron-shaped marks; postocular black stripe absent (at least in adults).................................................... L. praestans

13.1 Supracephalic scales can be edged with black; interstitial skin on dorsolateral region not as above; postocular black stripe present............................................................................................. 14

14. Dorsum uniform Light Greenish Cyan (149) or green (dark blue or greenish blue in preservative); supracephalic scales slightly edged with black; dorsal coloration of anterior portion of the body persisting throughout the length of the body; dorsal keels forming a series of parallel black lines.......................................................... L. occidentalis

14.1 Dorsum Cinnamon-Drab (50), Yellow-Green (103), Yellowish Spectrum Green (128), Light Emerald Green (142), Turquoise Green (147), Light Caribbean Blue (163), or metallic green (dark blue, greenish blue, or dark bluish green in preservative), at least on anterior portion of the body; supracephalic scales frequently edged with black; coloration of anterior portion of the body can be different from that of the rest of the body; dorsal scales with black or brown keels, but not forming a series of parallel lines........................................................................................ 15

15. Dorsal coloration can change gradually toward tail; ventral scales can be edged anteriorly and laterally with Robins’s Egg Blue (161) (dark greenish blue in preservative); some dorsal scales of the tail can be keeled.............................. 16

15.1 Dorsal coloration usually changes gradually to Olive Yellow (117) (light brown or darker brown in preservative) toward tail; ventral scales never edged anteriorly and laterally with Robins’s Egg Blue (161) (dark greenish blue in preservative); dorsal scales of the tail never keeled.................................................................... L. liocercus

16. Parietal and supraocular scales with no black spots; usually broad postocular black stripe occupying lower edge of upper postocular, upper edge of lower postocular, half or nearly all of anterior and posterior temporals, and upper edges of last two or three supralabials; keels on rows III-XII heavily black (more prominent on rows V-VII on either side), before the reduction to 11 dorsal scale rows; occasionally 13 dorsal scale rows at midbody....................................... L. urostictus

16.1 Usually one or two black spots on each parietal and supraocular scales; usually a narrow postocular black stripe reduced to black margin on posterior edge of lower preocular, lower edge of anterior temporal and lower posterior temporal or occupying lower edge to one third of anterior temporal, lower edged to half of lower posterior temporal, and upper edges of last two or three supralabials; keels on rows III–XII slightly black or brown; usually 15 dorsal scale rows at midbody.............. 17

17. Ventral scales usually edged anteriorly and laterally with Light Turquoise Green (146) (bluish green in preservative)............................................................................................ L. nigromarginatus

17.1 Ventral scales never edged anteriorly and laterally with Light Turquoise Green (146) (dark greenish blue in preservative).... .................................................................................................. 18

18. Usually two or more poorly defined, diffuse black spots on each parietal and distinct one or two black spots (occasionally elongate) on each supraocular; short keels usually present on entire length of dorsal scales of tail............. L. bolivianus

18.1 Usually a small, defined black spot on the center of each parietal scale and, in most specimens, on outer side of each supraocular; keels occasionally present on dorsal scales of tail posterior to the point of reduction from six to four rows...................................................................................................... L. marginatus

Species accounts

Figures

FIGURE 4. Distribution of Leptophis ahaetulla based upon the material examined.

FIGURE 8. Distribution of Leptophis bocourti, L. coeruleodorsus, L. occidentalis, L. praestans, and L. urostictus based upon the material examined.

FIGURE 18. Distribution of Leptophis bolivianus, L. liocercus, L. marginatus, and L. nigromarginatus based upon the material examined.