Leptophis bocourti Boulenger, 1898

Albuquerque, Nelson Rufino De & Fernandes, Daniel S., 2022, Taxonomic revision of the parrot snake Leptophis ahaetulla (Serpentes, Colubridae), Zootaxa 5153 (1), pp. 1-69 : 16-19

Leptophis bocourti Boulenger, 1898

( Figs. 6–7 )

Leptophis bocourti Boulenger, 1898: 116 . Three syntypes (female BMNH 1946.1.6.76 and males BMNH 1946.1.6.67—examined; BMNH 1946.1.6.68). Type locality: “Paramba and Cachabe [San Javier de Cachabí and San Javier de Cachavi, (01°04′21″N, 78°45′58″W, 45 m asl), Ecuador ”]; Griffin 1916: 184; Amaral 1930a: 15; Torres-Carvajal & Terán 2021: 2.

Leptophis occidentalis insularis Barbour, 1905: 101 . Male holotype (MCZ 6985; not examined). Type locality: Gorgona Island (02°58′03″N, 78°10′49″W, 330 m asl), Colombia; Parker 1926: 552.

Leptophis occidentalis bocourti — Oliver 1942: 15; Nicéforo-Maria 1942: 90.

Thalerophis richardi bocourti — Oliver 1948: 223.

Leptophis ahaetulla [ bocourti ]— International Commission of Zoological Nomenclature 1958: 270.

Leptophis ahaetulla bocourti — Peters 1960: 526; Peters & Orejas-Miranda 1970: 162; Pérez-Santos & Moreno 1988: 208; Pérez-Santos & Moreno 1991: 214; Tipton 2005: 161.

Leptophis ahaetulla — Pazmiño-Otamendi 2017, unpaged (in part); Torres-Carvajal et al. 2018: 241 (in part).

Diagnosis. Leptophis bocourti can be distinguished from its congeners by the following unique combination of character states: (1) head scales narrowly edged with black and with numerous small, irregularly shaped black spots; (2) adult color pattern with no dark dorsal bands; (3) dorsum dark slate gray or ultramarine with numerous small, irregularly shaped black spots, also present on extreme outer edge of ventrals; (4) dorsal scales keeled, except first dorsal row on each side; keels of dorsals more prominent on paravertebral and vertebral rows; (5) no loreal scale; (6) ventrals 157–167 in males, 159–167 in females; (7) subcaudals 166–186 in males, 164–173 in females; (8) two median rows of dorsal scales of tail keeled for most of tail length; (9) maxillary teeth 22–23; characters 10–12 could not be evaluated due to reduced sample size.

Comparisons. Leptophis bocourti is distinguished from all members of the L. ahaetulla complex by its unique color pattern of head scales narrowly edged with black and with numerous small, irregularly shaped black spots, dorsum and outer edge of ventrals with numerous small, irregularly shaped black spots ( Fig. 6A–C ) (vs. small, irregularly shaped black spots absent on the head, dorsum and outer edge of ventrals in the remaining taxa).

Variation and sexual dimorphism. Largest male SVL 975 mm, TL 621+ mm and largest female SVL 826 mm, TL 511+ mm; ventrals 157–167 in males (162.3 ± 3.3, n = 7), 159–167 in females (162.1 ± 2.8, n = 7); subcaudals 166–173 in males (175 ± 10.1, n = 3), 164–176 in females (168.3 ± 5, n = 6); supralabials 8–9 (8.9 ± 0.3, n = 30), with fifth–sixth (87.5%, n = 28), fourth–fifth (12.5%, n = 4) bordering orbit; infralabials 10–11 (10.2 ± 0.7, n = 32), with first 6 (50%, n = 16) and first 5 (50%, n = 16) contacting first chin shields; preocular 1 (n = 16); postoculars 2 (n = 16); anterior temporal 1 (n = 16); posterior temporal 2 (n = 16); keels more developed in adult males than females and juveniles; keels present on dorsal scale rows II–XIV in males, and VI–X in females.

Two banded specimens were examined: MZUSP 8250, a male of 375 mm in total length, and QCAZ 8023, a possible female (Vincent Premel, pers. comm. 29 Jun. 2020) specimen of 516 mm in total length with bands in anterior and middle regions of body.

Hemipenial morphology. Not analyzed for this species. Oliver’s (1948) description is based on an inverted hemipenis (catalogue number unknown) extending up to the seventh subcaudals with six basal spines extending up to second subcaudals; five to six transverse rows of smaller, stouter spines extending up to subcaudals 3 and 4. Spines decrease in size distally, turning into calyces with fringing papillae; papillae decrease in length and number distally, while calyces increase in size. Distal portion of the organ typically calyculate.

Coloration in life. Dorsum of the head Dark Egg Blue (162) and narrowly edged with black; head and dorsal scales ornamented with numerous small, irregularly shaped black spots; spots also present on extreme outer edge of ventrals anteriorly; in the juvenile specimen, the color of the scales on the first two dorsal rows is yellow and their supracephalic scales and dorsum do not contain black spots; keels of dorsal scales black, more prominent on paravertebral and vertebral rows; jet Black (300) preocular stripe usually reduced to black margin on second, third, and fourth supralabials; a broad Jet Black (300) postocular stripe covering upper edge of lower postocular, lower edge of upper postocular, two-thirds of anterior temporal, half to two-thirds of lower posterior temporal, lower edge of upper posterior temporal, and upper edges of last three supralabials; postocular stripe usually not extending beyond one scale onto nuchal region; supralabials, infralabials, chin, and throat white to Light Turquoise Green (146); some supralabials may be suffused with Sulphur Yellow (80); black spots may be present on upper edge of supralabials, infralabials, and chin and on extreme outer edge of ventrals; rows I–II and outer edge of ventrals in anterior portion of the body (before body scale reduction from 15 to 11) Sulphur Yellow (80) in juveniles. Pérez-Santos & Moreno (1991: 210) briefly described the color pattern of L. a. bocourti .

Distribution and natural history. Leptophis bocourti is known only from northwestern Ecuador and Gorgona Island, Colombia, at altitudes up to 200 m asl ( Fig. 8 ). This taxon occurs in dense, humid, tropical forest ( Oliver, 1948), corresponding to the tropical and subtropical moist broadleaf forests ecoregion, as defined by Olson et al. (2001).

Remarks. The yellow color of scales on the first two dorsal rows and the absence of black spots in the supracephalic scales and dorsum of the single juvenile specimen examined suggests a distinct ontogenetic color change in Leptophis bocourti , as also observed in L. nigromarginatus and L. occidentalis ( Oliver 1948; Duellman 1978; McCranie et al. 2006).

Figures

FIGURE 6. Color patterns and color tones variability of Leptophis bocourti: Male syntype BMNH 1946.1.6.67, SVL 1596 mm (incomplete tail). General (A) dorsal (B) and lateral (C) views of the head. Note the head scales and dorsum with numerous small, irregularly shaped black spots. Scale bars = 0.5 cm. Photos by N.R. Albuquerque.

FIGURE 7. Color patterns and color tones variability of Leptophis bocourti: (A) USNM 285488, an adult from Santo Domingo de los Colorados, 47 km S of Centro Cientifico Río Palenque, province of Los Rios and (B) QCAZ 8023, a juvenile from province of Durango, Ecuador. Used under CC BY-NC-ND 4.0 https://bioweb.bio/galeria/Album/Leptophis%20ahaetulla. Note that the dorsal color in adults is essentially green in life, but in the juvenile specimen, the color of scales in dorsal rows 1–2 is yellow (indicated by the arrow). Further, the dorsum of the juvenile lacks the small, irregularly shaped black spots of adults, suggesting a distinct ontogenetic color change. Photos by R.W. McDiarmid (A) and S. Ron (B).

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