Leptophis occidentalis ( Günther, 1859 )

Albuquerque, Nelson Rufino De & Fernandes, Daniel S., 2022, Taxonomic revision of the parrot snake Leptophis ahaetulla (Serpentes, Colubridae), Zootaxa 5153 (1), pp. 1-69 : 41-44

Leptophis occidentalis ( Günther, 1859)

( Figs. 22E–F , 27–29 )

Ahaetulla occidentalis Günther, 1859: 412 . Male syntypes ( BMNH 1946.1 .4.48 and BMNH 1946.1.6.62; the latter examined). Type locality: “ Guayaquil and western Ecuador ”.

Thrasops occidentalis — Cope 1860: 552.

Leptophis ultramarinus Cope, 1894: 203 . Holotype male (AMNH 17363; examined).Type locality: Pazo [Pozo]Azul (10°11‘684° N, 54‘18 W, 252 m asl), Costa Rica, added to synonymy of L. a. occidentalis by Oliver 1948: 241; Amaral 1930a: 18.

Leptophis bocourti — Griffin 1916: 184.

Leptophis occidentalis — Griffin 1916: 185; Schmidt 1933: 16; Barrio-Amorós & Ortiz 2015: 85; Torres-Carvajal & Terán 2021: 2.

Leptophis flagellum — Amaral 1930a:16 added to synonym of L. occidentalis .

Leptophis ahaetulla — Nicéforo-Maria 1933: 48 (in part); Guyer & Donnelly 2004: 198 (in part); Wilson & Meyer 1982: 73 (in part); Wilson & Meyer 1985: 65 (in part); Savage 2002: 668 (in part); McCranie & Castañeda 2005: 8 (in part); McCranie et al. 2006: 159 (in part); McCranie 2011: 140 (in part); Gómez-Hoyos et al. 2015: 197 (in part); McCranie 2015: 372 (in part); Pazmiño-Otamendi 2017, unpaged (in part); Torres-Carvajal et al. 2018: 241 (in part).

Leptophis occidentalis occidentalis — Amaral 1930b: 85; Amaral 1930c: 162; Oliver 1942: 14; Nicéforo-Maria 1942: 90; Daniel 1949: 310.

Thalerophis richardi occidentalis — Oliver 1948: 241; Taylor 1951: 86.

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

Leptophis ahaetulla occidentalis — Peters 1960: 526; Peters & Orejas-Miranda 1970: 163; Pérez-Santos & Moreno 1988: 211; Pérez-Santos & Moreno 1991: 217; Kornacker 1999: 99; Tipton 2005: 162.

Leptophis santamartensis Bernal-Carlo & Roze, 1994: 46 . Male holotype IavH 3241 (formerly IND 3241; examined by Albuquerque et al. 2012) from Ciudad Perdida (10°42’20 N, 74°12’21 W, 19 m asl), Sierra Nevada de Santa Marta, Department of Magdalena, Colombia, added to synonymy of L. a. occidentalis by Albuquerque et al. (2012).

Diagnosis. Leptophis occidentalis can be distinguished from its congeners by the following unique combination of character states: (1) head scales slightly edged with black and with no black spots; (2) adult color pattern with no dark dorsal bands; (3) dorsum uniformly dark blue or greenish blue; (4) keeled dorsal scales, except first dorsal row on each side; keels absent or reduced on the vertebral row; keels on dorsal scale rows II–XIV (or only VI –X) black; (5) no loreal scale; (6) ventrals 147–178 in males, 150–183 in females; (7) subcaudals 130–188 in males, 134–194 in females; (8) dorsal scales of tail with no keels; (9) maxillary teeth 22–24; (10) TL/ SVL: 95% CI = 0.600 –0.626 (n = 90); (11) enlarged spines at first basal row of hemipenial body, (12) papillate calyces more numerous on sulcate side of hemipenial body .

Comparisons. Leptophis occidentalis differs from all members of the L. ahaetulla complex by the combination of head scales slightly edged with black ( Fig. 28 ) (vs. usually not edged with black) and with no black spots ( Fig. 28 ) (vs. black spots present); dorsum uniformly dark blue or greenish blue in preservative (vs. dorsum with two dorsolateral stripes); and black keels on dorsal scale rows VI–X ( Fig. 29A ) or II–XIV ( Fig. 29B ), forming a series of parallel black lines (vs. dorsal scales with black or brown keels, but not forming a series of parallel lines). Papillate calyces are more numerous on the sulcate side of the hemipenis of L. occidentalis ( Fig. 22E ) (vs. a similar number of papillate calyces on either side of the hemipenis of all members but L. praestans ); it is further distinguished from the occasionally sympatric L. bocourti by the absence of small, irregularly shaped black spots on the scales of the head and dorsum (vs. spots present on the head and dorsum of L. bocourti ).

Variation and sexual dimorphism. Largest male SVL 1450 mm, TL 835+ mm and largest female SVL 1196 mm, tail 730+ mm; ventrals 147–178 in males (166 ± 6.2, n = 130), 150–183 in females (168.6 ± 7.2, n = 96); subcaudals 130–188 in males (164 ± 16.2, n = 51), 134–194 in females (162.7 ± 15, n = 36); supralabials 7–10 (8.5 ± 0.5, n = 450), with fifth–sixth (50.7%, n = 228), fourth–fifth (48.9%, n = 220), or, rarely, fifth–sixth–seventh (0.4%, n = 2) bordering orbit; infralabials 8–12 (10.1 ± 0.6, n = 450), with first 5 (78.3%, n = 351), first 6 (20.8%, n = 93), or, rarely, first 4 (0.7%, n = 3), and first 7 (0.2%, n = 1) contacting first chin shields; preoculars 1–2 (1.0 ± 0.1, n = 450); postoculars 1–3 (2.0 ± 0.2, n = 448); anterior temporal 1 (n = 224) and a single specimen with 2 on both sides; posterior temporal 1–2 (1.9 ± 0.2, n = 450).

The only banded specimen examined was UMMZ 128818, a male with 561 mm in total length, with bands in anterior, middle and posterior portions of the body. Females have more ventrals than males (F 1,225 = 7.8095; P <0.01). No significant difference in subcaudal counts between males and females was observed (F 1,87 = 0.2617; P = 0.6165). The TL/SVL showed no significant difference between females and males (F 1,88 = 0.2125; P = 0.6509).

Hemipenial morphology. Ten retracted organs examined extend up to five–six subcaudals. Nime everted hemipenis slightly bilobed and one unilobed (FMNH 165452), noncapitate; sulcus spermaticus centrolineal, undivided, extending from base to tip of lobe; basal portion bears numerous stouts, enlarged-sized spines distributed in 5–7 rows approximately encircling the organ; first row bears 5–7 large hooked spines; spines in the first row notoriously larger than those in other rows; one-two spines in the first row adjacent to sulcus spermaticus larger than others; small spines adjacent to sulcus spermaticus that become papillae on the middle portion of hemipenial body; calyces ornamented with 6–10 papillae originate above distal row of basal spines on sulcate side; papillae gradually decrease in length and number toward distal portion of hemipenial body; papillae less abundant in asulcate side, whereas calyces increase in size; distal portion of lobe either nude (on asulcate side) (MVZ 217614) or ornamented with few papillate calyces irregularly distributed (on sulcate side) (ANSP 32397); papillate calyces more numerous on sulcate side; calyces either concentrated only on distal region of asulcate side (KU 75725), or totally absent (AMNH 119080) ( Fig. 22E–F ).

Coloration in life. Dorsum of the head Light Greenish Cyan (149) or green and slighly edged with black; preocular Jet Black (300) stripe always absent or reduced to black margin on upper edges of two supralabials immediately anterior to orbit; postocular Jet Black (300) stripe usually covers lower edge of upper postocular, upper edge of lower postocular, lower edge of anterior and posterior temporals, and upper edges of last two or three supralabials, extending no farther than one scale onto nuchal region; supralabials, infralabials, chin, and throat varying from white to Light Turquoise Green (146); some supralabials may be suffused with Yellow-Green (103); dorsum uniform Light Greenish Cyan (149) or green, with black keels in rows VI–X or II–XIV, forming a series of parallel black lines. Rows I–II (occasionally I–III) and lateral portions of ventrals may be Yellow-Green (103), at least in the anterior portion of the body; subcaudals Light Greenish Cyan (149) to green. Descriptions of the color pattern of L. occidentalis are given in Roze (1966: 173), Wilson & Meyer (1982: 73; 1985: 65), and McCranie (2011: 140) (named as L. ahaetulla in all these papers). Savage (2002, fig. 430) and McCranie et al. (2006, fig. 134) not only described but also published photos of this species (as L. ahaetulla ). Pérez-Santos & Moreno (1991, fig. 91) illustrated a specimen of L. a. occidentalis from Ecuador.

Distribution and natural history. Atlantic and Pacific coasts of Central America, from Honduras to trans- Andean regions of Colombia, Caribbean coast of Venezuela, to northwestern Ecuador and northern Peru. These snakes were collected up to 2410 m asl ( Dunn 1944), occupying the tropical and subtropical moist broadleaf forests ecoregion, as defined by Olson et al. (2001) ( Fig. 8 ). Donoso-Barros (1966) stated that L. occidentalis and other snakes “have been observed with some frequency in the fruit shipments of the ships arriving in Chile from tropical harbors” (our translation), by shipping activities from Ecuador. However, this species was not listed in an updated checklist of the native and introduced reptiles of Chile ( Ruiz De Gamboa 2016).

Five specimens (CAS 98550, SVL 738+ mm; CM 2011, SVL 1130+ mm; FMNH 54973, SVL 1156+ mm, UMMZ 124164, SVL 1211 mm; UMMZ 55895, SVL 949 mm) contained respectively six (the fifth, head-tail direction, measured 20.2 mm), five (the fifth 21.5 mm), four (the fifth 23.2 mm), three (the third 22.4 mm), and six (the sixth 31.8 mm) well-developed eggs each.

Remarks. McCranie et al. (2006) noted that a juvenile specimen from the Honduran Mosquitia had a distinct color pattern, with an olive-green dorsum and a bronze middorsal stripe, which reinforces Oliver’s (1948: 243) previous statements suggesting this species exhibits ontogenetic change in color pattern.

As noted by Oliver (1948: 243) the most remarkable variation in the external morphology of Leptophis occidentalis was observed in the distribution and prominence of keels on dorsal scales, which are subject to geographic variation. Specimens from the Atlantic side of Central America ( Honduras or Nicaragua) always have prominent keels only on scales rows VI–X at midbody ( Fig. 29A ), and there is no keel on scale row VI above the cloaca. In populations from the Pacific side of Central America, scale rows II–XIV are usually prominently keeled, and scale row VI above the cloaca is keeled. Nevertheless, the specimen illustrated in Figure 29B was captured in the State of Lara (Western Venezuela), and scale rows II–XIV possess prominent keels, matching the diagnosis presented by Oliver (1948) for populations from the Pacific side of Central America and Ecuador.

Figures

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

FIGURE 22. Sulcate (left) and asulcate (right) sides of the hemipenes of Leptophis marginatus (FML 1624) from Puerto Pilcomayo, departament of Pilcomayo, Formosa Province, Argentina (A-B); L. urostictus (AMNH 109753) from Guanguí stream, department of Cauca, Colombia (C-D); L. occidentalis (ANSP 32397), from province of Limón, Costa Rica (E-F); and L. praestans (KU 55716) from El Petén, Guatemala (G-H) sides. Note the first row of moderate-sized spines in the first two species, and the enlarged spines in the latter two species. Scale bars = 0.5 cm. Photos by N.R. Albuquerque.

FIGURE 27. Color pattern and color tones of Leptophis occidentalis: Male syntype of L. occidentalis, BMNH 1946.1.6.62, SVL 946 mm (incomplete tail), from “Guayaquil and western Ecuador”. General view (A). Black pigments are indistinct on most keels of dorsal scale rows in this specimen; however, the specimen has lost most of the stratum corneum, and as a result has not retained its original coloration. (B) Profile view. Note the presence of a postocular stripe (indicated by the arrow), a characteristic considered as indistinct when Günther (1859) described this species. Scale bar = 0.5 cm. Photos by J. Klaczko.

FIGURE 28. Color patterns and color tones variation of Leptophis occidentalis: MVZ 83435, SVL 1075 mm (incomplete tail) from Yaviza, province of Darién, Panamá. Note the supracephalic scales slightly edged with black. Scale bar = 0.5 cm. Photo by N.R. Albuquerque.

FIGURE 29. Color patterns and color tones variation of Leptophis occidentalis: (A) FMNH 282688 from Gracias a Díos, Bachi Kiamp, Honduras. Note that only the scales of rows VI–X possess prominent keels at midbody (i.e., before the reduction to 11 dorsal scale rows), which is typical (sensu Oliver 1948) in specimens of L. occidentalis from the Atlantic side of Central America; and (B) Uncollected specimen from El Limón, state of Aragua, Venezuela. The dorsal scales of rows II–XIV possess prominent keels, matching the diagnosis presented by Oliver (1948) to populations from the Pacific side of Central America. Photos by J.R. McCranie (A) and L.A. Rodríguez (B).