Tantilla stenigrammi, McCranie & Smith, 2017

McCranie, James R. & Smith, Eric N., 2017, A Review of the Tantilla taeniata Species Group (Reptilia: Squamata: Colubridae: Colubrinae) in Honduras, with the Description of Three New Species, Herpetologica 73 (4), pp. 338-348 : 339-342

Tantilla stenigrammi sp. nov.

( Figs. 3 , 4 )

Tantilla taeniata: McCranie 2011a:227 , in part; McCranie 2011b:44, in part.

Holotype. — University of Texas at Arlington ( UTA) R-52591 (Field No. ENS 10897 ), a subadult female from Cuaca (15°23 ′ 01.75 ′′ N, 86°12 ′ 41.22 ′′ W;. datum ¼ WGS 84 in all cases), 895 m elevation, department of Olancho, Honduras, collected 3 February 2005 by Eric N Smith, Jorge A. FerrariCastro, Jorge Murillo, C. Chavez, Arturo Sosa, and John H. Malone.

Paratype (n ¼ 1). — UNAH 3032 , an adult male with an incomplete head and tail, from about 20 km E of Gualaco, Olancho, Honduras, at beginning of a foot trail (15°02 ′ N, 85°54 ′ W) leading to Cerro La Picucha , 1180 m elevation .

Diagnosis. — Tantilla stenigrammi is defined, following Campbell (1998), by the following combination of characters: (1) middorsal stripe Warm Buff to Pale Horn Color (Color 118, 92), extending length of body and most of tail, confined to vertebral row on at least anterior half of body, extending onto adjacent edges of paravertebral scale rows posteriorly on body; (2) Buff-Yellow (Color 53) lateral stripe occupying adjacent thirds of scale rows 3 and 4; (3) ventrolateral area similar in pale color to that of lateral stripe; (4) lower half to two-thirds of scale row 1 colored similarly to that of ventrals; (5) lateral edges of ventrals immaculate white (in preservative), no dark spots present; (6) ventral and subcaudal surfaces Pearl Gray (in life; Color 81) to white (in preservative); (7) female with 159 ventrals, male with 164 ventrals; (8) tail incomplete in both.

Tantilla stenigrammi can be distinguished from T. taeniata by having the pale middorsal stripe confined to the vertebral row on at least anterior half of body and in having pale gray ventral surfaces in life (vs. pale middorsal stripe also extending onto paravertebral rows throughout its length and ventral surfaces pale purplish pink grading to darker salmon color on posterior two-thirds of body and under tail in T. taeniata ). It further differs from T. taeniata in having more ventral scales (164 vs. 141–152 in males, and 159 vs. 150 in females).

Tantilla stenigrammi differs from T. psittaca and T. tritaeniata by having the middorsal pale stripe confined to the vertebral row on at least anterior half of body (vs. middorsal stripe involving all of vertebral scale. and adjacent third to half of paravertebral scale rows throughout its length in those two species); further from T psittaca by having pale gray ventral and subcaudal surfaces in life and white in preservative (vs. those surfaces being pink and grading to red in life and pale brown medially and pale brown with pinkish tinge on posterior third of body and under tail in preservative), and further from T. tritaeniata in having a complete nuchal collar and the pale lateral stripe covering adjacent thirds of scale rows 3 and 4 (vs. nuchal collar divided and pale lateral stripe including adjacent halves to two-thirds of scale rows 3 and 4). Tantilla stenigrammi differs from T. impensa in having 159 ventrals in the female, the pale middorsal stripe extending onto adjacent edges of paravertebral scale rows only posteriorly on the body, the pale brown lateral stripe covering adjacent thirds of scale rows 3 and 4, and by having a pale brown crossbar on the internasals that is bordered on the posterior edge by a dark brown cross-line (vs. 164–172 ventrals in females, the pale middorsal stripe confined to vertebral row throughout its length, pale lateral stripe including adjacent halves to twothirds of scale rows 3 and 4, and those head surfaces same ground color as remainder of head). Tantilla stenigrammi differs from T. olŋmpia in having complete middorsal and lateral pale stripes, in having a pale internasal crossbar, and having distinct pale large spots on the lateral surface of the head (vs. those body pale stripes reduced to dashes and spots, respectively, no internasal crossbar, and those lateral pale areas on head absent to indistinct).

Description of holotype. —A subadult female; TOL 173 mm plus tail tip; SVL 137 mm; TAL 36 mm plus tail tip (20.8% plus tail tip of TOL); HL 4.6 mm; HW 3.4 mm (level of angle of mouth); head barely distinct from neck; snout broadly rounded in dorsal view; eye length 1.1 mm; snout length 2.2 mm, about 2.0 times longer than eye; pupil circular; rostral about 1.2 times wider than high (1.2 X 1.0 mm); internasal length about three-quarters of width (0.8 X 1.1 mm); prefrontal much larger than internasal, wider than long (1.3 X 0.9 mm); median prefrontal suture 0.9 mm, nearly half as long as frontal; frontal with slight anterior extension, V-shaped posteriorly, about 1.3 times longer than wide (2.1 X 1.6 mm), 1.3 times longer than distance from its anterior edge to tip of snout (2.1 X 1.6 mm); parietal about 1.6 times longer than wide (3.0 X 1.9 mm), median suture length 1.6 mm, about 0.8 times frontal length; parietals contacting seven nuchal scales; supraocular about 1.8 times longer than wide (1.6 X 0.9 mm), bordering orbit, contacting parietal, upper postocular, preocular, and prefrontal.

Nasal divided, anterior nasal contacting rostral, internasal, and first supralabial, posterior nasal contacting internasal, prefrontal, preocular, and first and second supralabials, nostril located in central portion of nasal (forming division of nasal); loreal absent; preocular single, as high as long (both dimensions 0.5 mm), lower edge contacting supralabials 2 and 3; postoculars 2, upper about same size as lower (height of both 0.5 mm); temporals 1 þ 1, anterior temporal 1.1 times longer than high (1.0 X 0.9 mm), posterior temporal 1.6 times longer than high (1.3 X 0.8 mm); supralabials 7, 3rd and 4th bordering orbit, 4th and 5th contacting lower postocular, 5th and 6th contacting anterior temporal, and 7th contacting anterior and posterior temporals; infralabials 6, first 3 contacting anterior pair of chinshields, infralabial 1 on each side separated medially by contact with anterior chinshield; mental 1.7 times wider than long (1.2 X 0.7 mm), contacting first pair of infralabials and anterior pair of chinshields; anterior chinshields 2.1 times longer than wide (1.9 X 0.9 mm), not extending laterally to border of lip; posterior pair of chinshields 1.9 times longer than wide (1.3 X 0.7 mm), posterior tips separated from each other by one gular scale; three preventral scales present between gular and ventral 1; dorsal scales in 15–15–15 transverse rows, smooth throughout, lacking apical pits and supracloacal tubercles; dorsal scales in eight rows at level of subcaudal 10; ventrals 159; cloacal scute divided; subcaudals 64 plus tail tip (an estimated 5–10 subcaudal scales missing), paired; ventrals plus subcaudals 223 plus tail tip.

Ventrals Subcaudals TAL/TOL

n Species Males/Females Males Females Males Females Males Females Maximum TOL T. excelsa 3/1 169 161–178 70 61 24% 23% 400 mm T. gottei 6/1 142–158 147 62–67 70 24–26% 26% 367 mm T. impensa 9/12 161–171 164–172 68–72 64–72 21–24% 21–25% ~ 725 mm T. olŋmpia 1/0 148 — 49 — 21% — 338 mm T. psittaca 4/3 153–163 154–161 63–73 — 24–25% — 413 mm T. stenigrammi 1/1 164 159 — — — — 173 mmþ T. taeniata 9/1 141–152 150 60–70 59 23–27% 23% 415 mm T. tritaeniata 1/2 157 155–161 — 59–65 — 23–24% 273 mm

Color of holotype in life ( Fig. 3 ). —Coloration of freshly euthanized holotype (UTADC 8752–53): dorsum of head Olive-Brown (28), transforming to Sepia (219) along scale margins; anterior portion of rostral, supralabial 1, and nasals Sepia; posterior portion of rostral, internasal, and interparietal areas Grayish Horn Color (91); two Pale Horn Color (92) lateral spots on head, first occupying postnasal, lower edge of prefrontal, anterior tip of preocular, and most of supralabials 1 and 2, second lateral spot located posterior to eye and occupying most of lower postocular, lower borders of upper postocular and parietal, part of supralabials 4 and 6 and all of supralabial 5, and anterior half of anterior temporal; nuchal collar Warm Buff (118) dorsally to Pale Horn Color laterally, with Sepia anterior and posterior borders, collar about two dorsal scales long and occupying posterior tips of parietal and secondary temporal, and posterior third of supralabial 7; dorsum of body Hair Brown (119A), turning Sepia alongside all pale body stripes and toward nuchal collar; middorsal stripe Warm Buff, occupying only vertebral scale row anteriorly on body, extending onto adjacent edges of paravertebral scale rows posteriorly on body, beginning one and a half scales posterior to nuchal collar, stripe extending onto tail to reach tip, occupying adjacent halves of two most-middorsal scale rows; lateral body stripe on each side Buff-Yellow (53), occupying adjacent thirds of scale rows 3 and 4, beginning three scales posterior to nuchal collar, pale stripe on tail occupying second dorsal scale row and ending about 10 scales anterior to tip; underside of head mostly Pearl Gray (81), but Smoke Gray (44) toward mouth, and mental and buccal borders of infralabials 1–4 Sepia; venter of body, including anal plate, Pearl Gray, Smoke Gray toward sides, underside of tail Pearl Gray; ventral coloration extends to middle of dorsal scale row 1 on body, occupying all of dorsal scale row 1 on tail.

Color of holotype in preservative ( Fig. 4 ). —Dorsal surfaces brown with white nuchal collar and white middorsal and lateral stripes; pale middorsal stripe confined to vertebral row on at least anterior half of body, and extending onto adjacent edges of paravertebral rows posteriorly on body, with lateral tips of each vertebral scale dark brown; pale middorsal stripe not narrowing anteriorly on first scale involved in stripe; pale middorsal stripe extending onto tail, fading out at about a third of its length until becoming poorly visible at about midlength of tail; pale middorsal stripe beginning on 4th scale posterior to parietals; pale lateral stripe present on adjacent thirds of scale rows 3 and 4, bordered above by continuous, thin dark brown line; pale lateral stripe beginning on 5th scale posterior to ultimate (7th) supralabial, extending well onto tail; lower two-thirds of scale row 1 white; upper third of scale row 1, all of scale row 2, and lower third of scale row 3 same shade of brown as paravertebral rows; pale nuchal collar complete, involving posterior tips of parietals plus one and one-half scale rows dorsally, pale nuchal collar also involving posterior third of ultimate supralabial plus one scale row laterally; dorsal surface of head generally brown; off-white crossbar involving upper tip of rostral and both internasals, crossbar bordered posteriorly by dark brown cross-line involving posterior tips of internasal scales; lateral tips of each parietal scale white, contacting off-white line following parietal suture; anterior lateral white spot involving lower tips of prefrontals, postnasal, posterior two-thirds of supralabial 1, and all but posterior edge of supralabial 2; larger lateral white spot also present posterior to eye, involving all of supralabial 5 and anterior edge of supralabial 6, extending dorsally to cover about anterior half of anterior temporal; dark brown lateral bar covering posterior half of anterior temporal, all of posterior temporal, and posterior three-quarters and anterior two-thirds of supralabials 6 and 7, respectively; dark brown lateral bar extending dorsally to lateral third of parietal, not narrowing dorsally; about anterior half of mental and lateral tips of infralabials 1 and 2 dark brown, small portions of infralabials 3 and 4 with brown spots, remainder of ventral surface of head white; ventral surface of body white for full length, white pigment also extending onto lower tips of scale row 1 on body; subcaudal surface white, except upper tips of subcaudal scales dark brown.

Variation in paratype. —The paratype is an adult male that lacks part of its head and most of its tail, thus no measurements were taken, nor was the color pattern recorded by JRM when examined. Data and photographs in preservative provided by J.E. Mérida (26 December 2016), however, indicate that it has 164 ventrals and a narrow vertebral stripe anteriorly on the body and extending onto adjacent edges of paravertebral scale rows posteriorly on body; thus, similar to that of the holotype.

Distribution and habitat. —The holotype of Tantilla stenigrammi was found at 1630 h beside the school in Cuaca, Olancho ( Fig. 5 ). The specimen was under a root mat on the buttress of a fallen tree about 1 m above ground, and that site located between a soccer field and secondary vegetation. The historic habitat of Cuaca was pine–oak forest (Premontane Moist Forest of Holdridge [1967]) along the flanks of Montaña de Botaderos in a transition zone between pine– oak forest and broadleaf rainforest (Premontane Wet Forest). The highest elevations of the Botaderos Mountains contain remnants of closed-canopy broadleaf rainforest (Lower Montane Wet Forest), usually referred to as ‘‘cloud forest.’’

The paratype was found dead during the day near the start of a foot trail in pine–oak forest ( Premontane Moist Forest ) along the lower flanks of the Sierra de Agalta. That trail also passes through Premontane Wet Forest , before ultimately entering Lower Montane Wet Forest as it gains altitude. Thus , both specimens of Tantilla stenigrammi were found in similar, formerly forested areas, and at similar elevations (895 and 1180 m) in north-central and central Olancho in east-central Honduras. Both localities are in low mountains on both sides of the upper drainage of the Río Sico Tinto (also called Río Negro) that forms the Agalta Valley ( Fig. 5 ) .

Remarks. —A photograph of the holotype (UTA R-52591) of Tantilla stenigrammi was previously published in McCranie et al. (2006; as T. taeniata ).

Etymology. —The specific epithet, stenigrammi , is a Greek substantive used as an adjective and meaning narrow-lined, derived from the Greek adjective stenos (narrow) and the Greek noun grammi (line), in allusion to the narrow middorsal stripe that is characteristic of the species.

Figures

FIG. 3.—Tantilla stenigrammi holotype (UTA R-52591) in life, a subadult female. Total length of head, body, and tail ¼ 173 mm plus tail tip. Image taken by ENS (UTADC 8755). A color version of this figure is available online.

FIG. 4.—Lateral view of the head and body of the Tantilla stenigrammi holotype (UTA R-52591). Head length ¼ 4.6 mm. Image taken by JRM (UTADC 8864). A color version of this figure is available online.

FIG. 5.—Map showing localities for the species of the Tantilla taeniata group known to occur in Honduras, including three new species (T. excelsa, T. gottei, and T. stenigrammi). Type localities are indicated by filled symbols. Known localities in adjacent Guatemala are shown for T. impensa.