Leptophis praestans ( Cope, 1868 )

Albuquerque, Nelson Rufino De & Fernandes, Daniel S., 2022, Taxonomic revision of the parrot snake Leptophis ahaetulla (Serpentes, Colubridae), Zootaxa 5153 (1), pp. 1-69 : 44-50

Leptophis praestans ( Cope, 1868)

( Figs. 22G–H , 30–32 )

Thrasops praestans Cope, 1868: 309 . Syntypes (male and female catalogued as USNM 6754 ; both examined). Type-locality:

Petén, Guatemala. Female lectotype by present designation (see Remarks). Thrasops (Ahaetulla) sargii Fischer, 1881: 229 . Holotype ( SMNS 2022 ). Type locality: Coban [Cobán] (15°28’15 N, 90°22’15

W, 1292 m asl), Guatemala. Destroyed during the Second World War, according to Schlüter & Hallermann 1997: 11. Leptophis maximus Weller, 1930: 1 . Type specimen unknown from an unknown origin. Leptophis occidentalis praestans — Oliver 1942: 16. Thalerophis richardi praestans — Oliver 1948: 248. Leptophis ahaetulla [ praestans ]— International Commission of Zoological Nomenclature 1958: 270.

Leptophis ahaetulla praestans — Peters & Orejas-Miranda 1970: 163; Duellman 1963: 241; Tipton 2005: 162.

Leptophis ahaetulla — Lee 1996: 335 (in part); Campbell 1998: 222 (in part); Stafford & Meyer 2000: 217 (in part); Wallach, Williams & Boundy 2014: 372 (in part); González-Sánchez et al. 2017: 288 (in part).

Leptophis praestans — Torres-Carvajal & Téran 2021: 6.

Diagnosis. Leptophis praestans can be distinguished from its congeners by the following unique combination of character states: (1) head scales finely edged with black and with no black spots; preocular stripe absent; postocular stripe absent (at least in adults) (2) adult color pattern with no dark dorsal bands; (3) dorsum dark blue, with bright white chevron-shaped marks on the interstitial skin; (4) keeled dorsal scales, except first dorsal row on each side; keels indistinct on the vertebral row; keels on dorsal scale rows V–VII and IX–XI black, with keels on paravertebral rows more prominent; (5) no loreal scale; (6) ventrals 162–182 in males, 171–186 in females; (7) subcaudals 159–182 in males, 165–186 in females; (8) dorsal scales of tail with no keels; (9) maxillary teeth 21–25; (10) TL/ SVL: 95% CI = 0.610 –0.660 (n = 20); (11) enlarged spines at first basal row of hemipenial body; (12) papillae less abundant in asulcate side, whereas calyces increase in size.

Comparisons. Leptophis praestans differs from all members of the L. ahaetulla complex by its unique dorsal color pattern, with bright white (Sulphur Yellow in life) chevron-shaped marks on the interstitial skin ( Fig. 30 ) (vs. chevron-shaped marks on the interstitial skin absent), and the absence of postocular stripe, at least in adults ( Fig. 30 ; see Remarks below) (vs. postocular stripe present in adults). Males and females of L. praestans also have the highest number of ventrals—95% CI = 173.7–175.5 and 177.3–179.5, respectively ( Table 2).

Variation and sexual dimorphism. Largest male SVL 1055 mm, TL 618 mm and largest female SVL 1362 mm, TL 724+ mm; ventrals 162–182 in males (174.7 ± 3.6, n = 55), 171–186 in females (178.5 ± 3.5, n = 33); Subcaudals 159–182 in males (174.2 ± 7, n = 13), 165–186 in females (178.5 ± 6.6, n = 11); supralabials 7–9 (8.3 ± 0.5, n = 450), with fourth–fifth (62.9%, n = 107), fifth–sixth (34.7%, n = 59), or, rarely, only fourth (1.2%, n = 2), fourth–fifth–sixth (0.6%, n = 1), and third–fourth (0.6%, n = 1) bordering orbit; infralabials 9–11 (10.0 ± 0.5, n = 170), with first 5 (86.8%, n = 151), first 6 (12.6%, n = 22), or, rarely, first 4 (0.6%, n = 1) contacting first chin shields; preocular 1 (n = 88), and a single specimen with 2 on both sides; postoculars 2–4 (2.1 ± 0.4, n = 180); anterior temporal 1 (n = 89) and a single specimen with 2 on both sides; posterior temporal 1–2 (2.0 ± 0.2, n = 180); keels more developed in adult males than females and juveniles. Females have more ventrals than males (F 1,88 = 23.6994; P <0.01) but the average number of subcaudals was not sexually dimorphic (F 1,24 = 2.3854; P = 0.1334). The TL/SVL showed no significant difference between females and males (H = 1.7754; P = 0.1827).

Hemipenial morphology. Ten retracted organs examined extend up to seven-eight subcaudals. Everted hemipenis slightly bilobed, noncapitate; sulcus spermaticus centrolineal, undivided, extending from base to tip of lobe; basal portion bears numerous stout, enlarged-sized spines distributed in 5–7 rows approximately encircling the organ; first row bears 5–7 conspicuos hooked spines notoriously larger than those in other rows; spine in the first row adjacent to sulcus spermaticus larger than others; papillae adjacent to sulcus spermaticus immediately above most distal row of basal spines; calyces ornamented with 8–10 papillae concentrated on distal portion of organ; distal portion of lobe either completely calyculate (AMNH 46973), or nude (UTA 11068); papillate calyces more numerous on sulcate side; 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 ( Fig. 22G–H ).

Coloration in life. Dorsum of the head Grass Green (110) and finely edged in black; dorsal ground color uniform Grass Green (110), with Sulphur Yellow (80) chevron-shaped marks on interstitial skin more evident in inflated body; keels on V–VII and IX–XI dorsal scale rows black, with keels on paravertebral rows more prominent, forming a series of parallel black lines; supralabials, infralabials, chin, throat, and venter Light Turquoise Green (146) or Yellow-Green (103); upper portions of supralabials usually suffused with Grass Green (110). Lee (1996, fig. 368), Campbell (1998, fig. 139) and Stafford & Meyer (2000, fig. 128) described and illustrated the color pattern of L. praestans (as L. ahaetulla ), whereas Duellman (1963: 241) only briefly described the color pattern of L. praestans (as L. a. praestans ). Campbell & Lamar (2004, fig. 1173) illustrated a specimen of L. a. praestans from Guatemala.

Distribution and natural history. From central Veracruz, Mexico, southward through the Yucatán Peninsula, Belize, Guatemala, and Honduras. These snakes were collected up to 1160 m asl in the tropical and subtropical moist broadleaf forest, tropical and subtropical grasslands, savannas, and shrublands and tropical and subtropical coniferous forest ecoregions, as defined by Olson et al. (2001) ( Fig. 8 ).

Two specimens, UMMZ 76165 and UTA 37057, had eaten one Smilisca baudinii Duméril & Bibron and one Eleutherodactylus Duméril & Bibron , respectively, both anurans ingested headfirst.

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Remarks. A female, UMMZ 74851, with 567 mm in total length, retains traces of a postocular stripe reduced to black margin on eighth and nineth supralabials, occupying lower one-third of anterior temporal and lower one-third of posterior temporal ( Fig. 32 ), suggesting a possible ontogenetic change in L. praestans . Further, this specimen exhibits the banded juvenile pattern. USNM 136964, a female with 745 mm in total length, also retains traces of a postocular stripe reduced to black margin on anterior temporal and lower one-third of posterior temporal; this specimen does not exhibit the banded juvenile pattern. A male specimen (UTA 41190) from Guatemala illustrated by Campbell & Lamar (2004) (fig. 1173) measures 249.7 cm and is the longest known specimen of Leptophis .

Oliver (1948: 250) suggested that Leptophis praestans intergrade with L. occidentalis in the vicinity of the Segovia River in southeastern Honduras. This author, followed by Wilson & Meyers (1982, 1985), noted that the specimens USNM 24531–32 exhibit a mixture of the characters employed to diagnose the subspecies L. praestans and L. occidentalis . However, these specimens have a distinct black postocular stripe. In addition, their dorsal skin lacks white chevron-shaped marks, which allow their unequivocal identification as L. occidentalis .

Cope’s (1868) syntypes are faded though the white chevron-shaped marks are still evident. The female syntype, which has a complete tail, is here designated as the lectotype in order to preserve the traditional understanding and application of this name to L. praestans (Art. 74 of ICZN 1999 ). The male specimen ( Fig. 31 ) consequently becomes a paralectotype .

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 30. Color pattern and color tones of Leptophis praestans: UTA 12685 from Blue Creek Village, district of Toledo, Belize. Arrow indicating yellow chevron-shaped marks on the interstitial skin. Photo by W.W. Lamar, courtesy of J.A. Campbell.

FIGURE 31. Color pattern and color tones of Leptophis praestans: Male syntype USNM 6754 (paralectotype by designation), SVL 1748 mm (incomplete tail). General view (A). Although faded, the black keels on the V–VII and IX–XI dorsal scale rows and the chevron-shaped markings (indicated by the arrow) are still evident. (B) Profile view. Note the absence of postocular stripe, a condition typical of adult specimens. Scale bar = 0.5 cm. Photos by N.R. Albuquerque.

FIGURE 32. Color pattern and color tones of Leptophis praestans: Profile view of the UMMZ 74851 from El Petén, Guatemala. This juvenile specimen retains traces of a postocular stripe (indicated by the arrow) reduced to black margin on eighth and ninth supralabials, occupying lower one-third of anterior temporal and lower one-third of posterior temporal, suggesting a possible ontogenetic change in L. praestans. This condition is absent in adult specimens. Scale bar = 0.5 cm. Photo by N.R. Albuquerque.