Plestiodon lotus Pavón-Vázquez & Oca & Mendoza-Hernández & Centenero-Alcalá & Santa Cruz-Padilla & Jiménez-Arcos 2017, sp. nov.
Creators: name: Pavón-Vázquez, Carlos J.
name: Oca, Adrián Nieto-Montes De
name: Mendoza-Hernández, Andrés A.
name: Centenero-Alcalá, Eric
name: Santa Cruz-Padilla, Samuel A.
name: Jiménez-Arcos, Víctor H.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Scincidae
Plestiodon
Plestiodon lotus

description: Plestiodon lotus sp. nov.
(Figs. 4, 5)
Plestiodon brevirostris brevirostris (Günther, 1860) (in part); Feria-Ortiz et al. (2011:40–41, 43–47, 50, Table 6) Plestiodon brevirostris (Günther, 1860) (in part); Feria-Ortiz et al. (2011:46)
Plestiodon indubitus (Taylor, 1933) (in part); Feria-Ortiz & García-Vázquez (2012:57–58, 63–64, 66, 68, Table 1)
Holotype. MZFC-HE 30621. Adult male. 5.6 km N Xixila, Municipality of Olinalá, Guerrero, Mexico, 17°59'42'' N, 98°50'32'' W (datum = WGS84), 1525 m elevation. Collected by Víctor H. Jiménez-Arcos on 30 October 2011.
Paratypes. Thirteen specimens. GUERRERO: Municipality of Arcelia: Cañada El Limón, Campo Morado, 18°11'40'' N, 100°10'2'' W, 1173 m elevation (MZFC-HE 19787); Municipality of Atlixtac: 0.2 km from Petatlán graveyard (CNAR 24264); 0.3 km from Petatlán graveyard (CNAR 24265); Municipality of Leonardo Bravo: 3 km N La Escalera (CNAR 6585); Municipality of Olinalá: 2.7 km N Xixila, 17°58'1'' N, 98°50'38'' W, 1545 m elevation (MZFC-HE 30620); 5.3–5.4 km N Xixila, 17°59'36'' N, 98°51'2'' W, 1490 m elevation (MZFC-HE 30624), 17°59'36'' N, 98°51'3'' W, 1493 m elevation (MZFC-HE 30625), 17°59'34'' N, 98°51'4'' W, 1535 m elevation (MZFC-HE 30626). MORELOS: Municipality of Temixco: Acatlipa (CNAR 1774); Municipality of Tepalcingo: Sierra de Huautla, near Estación El Limón, 18°33'26'' N, 98°56'43'' W, 1420 m elevation (MZFC-HE 30622). OAXACA: Municipality of Santiago Tamazola: La Casita, Santiago Tamazola, 17°41'39'' N, 98°14'39'' W, 1770 m elevation (MZFC-HE 17503); Municipality of Silacayoápam: 5 km NE Santiago Tamazola, 17°42'46'' N, 98°12'22'' W, 1629 m elevation (MZFC-HE 30623). PUEBLA: Municipality of Chiautla: 11 km ESE Chiautla de Tapia, dirt road to San Juan de los Ríos, 18°14'15'' N, 98°29'32'' W, 1074 m elevation (MZFC-HE 30627).
Diagnosis. Plestiodon lotus can be distinguished from the other members of the P. brevirostris group as follows: from P. bilineatus and P. dicei, by the presence of a primary temporal (versus primary temporal absent in 89.4% [n = 52] of P. bilineatus and 98% [n = 52] of P. dicei); additionally from P. bilineatus by having a tendency towards more Toe-IV lamellae (13–15 [X=̄13.81, n = 27], versus 11–13 [X=̄11.7, n = 54] in P. bilineatus); and from P. dicei by having the interparietal enclosed posteriorly by the parietals (versus interparietal not enclosed posteriorly by the parietals in 94.2% [n = 52] of specimens in P. dicei).
Plestiodon lotus differs from P. brevirostris, P. copei, P. nietoi, P. ochoterenae, and P. parviauriculatus by having the primary lateral dark lines separated medially by the six median dorsal scale rows and upper half of the adjacent row on each side at the level of midbody (versus primary lateral dark lines separated medially by the median six dorsal scale rows or less invariably in the other species, except for 9.01% of the specimens [n = 122] of P. brevirostris); additionally from P. brevirostris, P. copei, P. ochoterenae, and P. parviauriculatus by having the interparietal enclosed posteriorly by the parietals (versus interparietal not enclosed posteriorly by the parietals in 82.64% [n = 122] of P. brevirostris, 96.77% [n = 62] of P. copei, 85.71% [n = 7] of P. ochoterenae, and 97% [n = 27] of P. parviauriculatus); and from P. brevirostris, P. copei, and P. nietoi by having a faint lower secondary dark line at the level of the neck (versus lower secondary dark line conspicuous at the level of the neck in the other species).
Plestiodon lotus differs from P. colimensis by having limbs that do not overlap when adpressed against the body (versus limbs overlapping when adpressed against the body in P. colimensis), a tendency towards fewer longitudinal dorsal scale rows around midbody (23–26 [X= ̄24.43, n = 14], versus 26–28 [X= ̄27, n = 4] in P. colimensis), and a tendency towards fewer Toe-IV lamellae (13–15 [X=̄13.81, n = 27], versus 13–17 [X=̄15.38, n = 8] in P. colimensis); from P. dugesii by having four supraoculars (versus three in P. dugesii); from P. indubitus and Plestiodon sp. Colima-Jalisco by having a solid lateral light line at level of neck (versus lateral light line replaced by a series of scales with white anterior edges and centers and black posterior borders in 90.91% [n = 33] of P. indubitus and 100% [n = 35] of Plestiodon sp. Colima-Jalisco); additionally from P. indubitus by having the light coloration of the supralabials extending to the lip border (versus light coloration separated from lip border on the sixth and seventh supralabials); from P. lynxe belli, P. l. lynxe and P. sumichrasti by having the interparietal enclosed posteriorly by the parietals (versus interparietal not enclosed posteriorly by the parietals in 100% [n = 36] of P. l. belli, 94.74% [n = 92] of P. l. lynxe, and 85.71% [n = 21] of P. sumichrasti) and lacking a light median line in all growth stages (versus dorsum bearing a light median line that is conspicuous in juveniles and faint in large adults); and from P. parvulus by having a relatively long dorsolateral light line extending posteriorly to the anterior fourth of the body or beyond (versus dorsolateral light line extending barely posteriorly past the shoulder in P. parvulus).
Description of holotype (Fig. 4). Adult male with both hemipenes partially everted. Snout–vent length (SVL) 53.1 mm; distance between tip of snout and anterior margin of orbit 4.6 mm, between tip of snout and anterior insertion of fore-limb 17.8 mm; trunk length 27.4 mm; head width 8.3 mm; head length 11.0 mm; tail complete, 64.1 mm in length. Limbs moderate in length, fingertips of fore-limb and hind limb separated from each other when limbs adpressed against body; straightened fore-limb (from base to tip of longest finger) 14.9 mm (28% SVL), straightened hind limb (from base to tip of longest toe) 15.6 mm (29.3% SVL); outer posterior tubercles of wrist and palm enlarged.
Snout rounded in dorsal and lateral view. Rostral 1.8 × wider than high, in broad contact with supranasals posteriorly; supranasals 1.2 × wider than long, in broad contact with each other and each with nasal, right supranasal with short oblique suture separating its posterolateral corner from rest of scale; frontonasal 1.8 × wider than long, posterior margin v-shaped, in contact with prefrontals posteriorly; prefrontals in contact with each other medially, 1.1/1 × wider than long, posterior margins v-shaped, in contact with first supraocular, anterior and posterior loreals, and first superciliary; frontal large, elongate, hexagonal, 1.9 mm wide, 3.2 mm long; in broad contact with prefrontals; in narrow contact with first and third supraoculars and wide contact with second supraocular on left side, in broad contact with second supraocular and narrow contact with third supraocular on right side; and in broad and narrow contact with frontoparietals and interparietal, respectively; frontoparietals narrowly separated from each other medially, in contact with third and fourth supraoculars laterally, and parietals and interparietal posteriorly; supraoculars four; first supraocular smaller than second and third, in lateral contact with first and second superciliaries; second supraocular largest, in lateral contact with second, third, fourth, and fifth superciliaries; third supraocular in lateral contact with fifth and sixth superciliaries; fourth supraocular smaller than second and third, in contact with sixth and seven superciliaries laterally and parietal posteriorly; interparietal small (2 mm wide, 2.7 mm long), slightly elongate, kite-shaped, in contact with parietals laterally and posteriorly; pineal foramen barely visible; parietals large, elongate, obliquely oriented, in medial contact with each other posteriorly, in contact with last superciliary, upper postsubocular, and upper secondary temporal laterally on each side, and in contact with left anterior nuchal on left side and both anterior nuchals on right side posteriorly; two pairs of large nuchals, scales of each pair in medial contact with each other; anterior nuchals 2.3/2.2 × wider than long; posterior nuchals 4.3 × wider than long; anterior nuchals in contact with parietals, upper secondary temporal and upper tertiary temporal.
Nasal divided in anterior and posterior halves, in contact with rostral; loreals 2/2; anterior loreal 1.7/1.2 × higher than long, divided horizontally on left side, in contact with first and second supralabials, posterior nasal, and posterior loreal; posterior loreal 1.3/1.4 × longer than high, notably larger than anterior loreal, in contact with anterior presubocular and second and third supralabials; preoculars 1/1, small; presuboculars 2/2, anterior presubocular in contact with third and fourth supralabials, posterior presubocular in contact with fourth and fifth supralabials; superciliaries 7/7; first superciliary largest, in contact with preocular ventrally; second to fifth superciliaries gradually becoming shorter and lower posteriorly; sixth superciliary nearly as high as fifth, horizontally elongate; last superciliary higher than anterior ones except first; upper palpebrals 9/10; lower palpebrals 10/11; lower eyelid movable; no transparent window in lower eyelid; 5/5 enlarged rectangular scales on lower eyelid; postoculars 2/2, small; postsuboculars 3/4; first postsubocular in contact with fifth and sixth supralabials, second postsubocular in contact with sixth supralabial and primary temporal, third postsubocular in contact with primary temporal and upper secondary temporal on left side, in contact with primary temporal on right side; fourth postsubocular on right side in contact with primary temporal and upper secondary temporal; temporal formula 1 + 2 + 1; primary temporal in contact with upper secondary temporal and sixth and seventh supralabials; upper secondary temporal large, in contact with tertiary temporal, lower secondary temporal, and sixth supralabial; lower secondary temporal vertically elongate, approximately as large as primary temporal, smaller than upper secondary temporal, separated from primary temporal by contact between upper secondary temporal and seventh supralabial; tertiary temporal large, 1.8/2.6 × higher than long; supralabials 7/7, first four gradually becoming lower posteriorly; fifth and sixth similar in size, larger than first four; seventh largest; postlabials 2/2.
Mental 2.5 × wider than long; infralabials 7/7; postmental larger than mental, in contact with anteriormost three and two infralabials on left and right side, respectively; three pairs of enlarged chinshields; first pair in broad contact with each other medially, second pair separated by one midgular scale, third pair separated by three midgular scales; scale bordering postgenial medially wider than long.
External ear opening rounded, smaller than eye opening, without lobules or spines; body scales smooth or barely striated, arranged in 28 longitudinal rows around neck just anterior to forearm, in 24 rows around midbody, in 13 rows around base of tail; dorsals in 51 transverse rows from nuchals to level above vent, subequal in size to ventrals; scales of limbs smooth or barely striated as in body; digits short; supradigital scales in one row; subdigital lamellae counts (following Myers and Donnelly, 1991): hand: I 5 /6 II 8 /8 III 9 / 9 IV 10 / 10 V 6 /7; foot: I 5 /5 II 8 / 8 III 11 / 11 IV 13 / 13 V 9 /9.
Median enlarged preanal scales nearly twice as wide as adjacent ventrals; first two transverse subcaudal rows as large as ventrals, remaining subcaudals about twice as wide.
Color in preservative (holotype). Middorsal light area olive (Greenish Olive 125); bordered on each side by dorsolateral light line (latter lines fusing with each other anteriorly on rostral and supranasals). Dorsolateral light lines light gray (Dark Pearl Gray 290), occupying lower half of second and upper half of third dorsal scale rows at level of midneck; occupying lower half of second, third, and upper half of fourth dorsal scale rows at midbody; gradually fading posteriorly to hind limbs. Upper secondary dark line dark brown (Sepia 279), bordering dorsolateral light line medially; solid, continuous on neck and anterior fourth of body; replaced by series of dark speckles on head, posterior three-fourths of body, and anterior half of tail; occupying upper half of second dorsal scale row at level of midneck; occupying middle portion of second dorsal scale row at level of midbody. Primary lateral dark line light brown on head (Dark Brownish Olive 127), darkening posteriorly (Sepia 279); beginning anteriorly on posterior nasal and ending posteriorly at level of hind limbs; bordering dorsolateral light line laterally; occupying lower half of third, fourth and fifth, and upper half of sixth dorsal scale rows at level of midneck; occupying lower half of fourth, fifth, and upper half of sixth dorsal scale rows at level of midbody. Lateral light line bluish gray (Pratt’s Payne’s Gray 293), bordering primary lateral dark line ventrally, partially fused at level of neck with light ventral coloration, but clearly comprising lower half of sixth and nearly all of seventh scale row; becoming indistinguishable from light ventral coloration at level of anterior insertion of fore-limb. Light ventral coloration light cream (Light Buff 2); fusing with dorsolateral light line on rostral and nasal; extending dorsally to mid supralabials (i.e., no discernible lateral light line on supralabials) at level of head, bordering lateral light line and primary lateral dark line ventrally at levels of neck and body, respectively; lateral borders throughout body and medial surface of posterior three-fourths of body heavily suffused with bluish gray (Pratt’s Payne’s Gray 293). Dorsal surface of limbs olive (Greenish Olive 125); ventral surface of fore-limbs and hind limbs light cream (Light Buff 2) and bluish gray (Pratt’s Payne’s Gray 293), respectively. Dorsal and lateral surfaces of anterior half of tail olive (Greenish Olive 125) and bluish gray (Pratt’s Payne’s Gray 293), respectively; dorsal and lateral surfaces of posterior half of tail dark gray (Medium Plumbeous 294); ventral surface of tail light cream (Light Buff 2).
Color in life (Fig. 5). The present section is based on photographs of the paratypes in life. Dorsal surface of head, mid-dorsal light area, and anterior portion of tail ranging from brownish silver to metallic gold, posterior border of each scale dark; dorsolateral light line broad, faint, yellowish cream, somewhat diffuse in large specimens; narrower, conspicuous, clear-cut in small ones; primary lateral dark line dark brown; lower portion of supralabials yellowish cream, suffused with orange in males; lateral light line light gray; infralabials and gular region yellowish cream, suffused with orange in males; ventral surface of body light gray with suffusion of light blue; ventral surface of anterior portion of tail light gray with suffusion of orange; posterior portion of nonregenerated tail electric blue.
Variation (measurements in mm). Noteworthy variation in the type series (n = 14, including holotype) is described below. The holotype is included to ease comparison with other species. The diagnostic traits of Plestiodon lotus were observable in specimen CNAR 1774, but considerable damage to the specimen prevented the recording of the number of supraoculars contacting the frontal, postsuboculars, postsuboculars contacting the sixth supralabial, and the presence or absence of contact between the upper postsubocular and the upper secondary temporal. Thus, CNAR 1774 is excluded from the reported variation in those traits. Additionally, the following characters could only be recorded on the left side: number of superciliaries, scales contacting the upper secondary temporal between the upper postsubocular and the first nuchal, postlabials, and the scales contacting both the upper secondary temporal and the upper postlabial.
Frontonasal absent in one specimen (CNAR 24264); frontonasal and frontal in contact in four specimens (CNAR 24265; MZFC-HE 24159, 30623–30624); supraoculars contacting frontal 2–3, X=̄2.88 (2/2 one; 3/2 one; 3/3 eleven, including holotype); postnasals present in one specimen (MZFC-HE 30622); anterior loreal divided horizontally on left side in one specimen (MZFC-HE 30621, holotype); contact between upper presubocular and third supralabial present on both sides in eleven specimens (including holotype), on left and right side in one specimen each, absent on both sides in one; superciliaries 6–8, X=̄7 (6/7 one; 7/7 eleven, including holotype; 7/8 one; 7 on left side of CNAR 1774); postsuboculars 3–5, X=̄3.77 (3/3 two; 3/4 one [holotype]; 4/3 two; 4/4 seven; 4/5 one); postsuboculars contacting sixth supralabial 2–3, X= ̄2.42 (2/2 seven, including holotype; 3/2 one; 3/3 five); primary temporal in dorsal contact with parietal, separating upper postsubocular from upper secondary temporal, on right side in one specimen (MZFC-HE 17503); sixth supralabial divided horizontally in one specimen (MZFC-HE 30622); scales contacting upper secondary temporal between upper postsubocular and first nuchal 3–5, X= ̄ 3.78 (3/3 three; 4/3 one; 4/4 eight, including holotype; 4 on left side of CNAR 1774; 5/4 one); seventh supralabial contacting upper secondary temporal in eight specimens (CNAR 24265; MZFC-HE 19787, 30620– 30621, 30623, 30625–30627), separated from each other by an extended lower secondary temporal in six (CNAR 1774, 6585, 24264; MZFC-HE 24159, 30622, 30624); postlabials 1–3, X= ̄1.89 (1/1 one; 1/2 one; 2/1 one; 2/2 nine, including holotype; 2/3 one; 2 on left side of CNAR 1774); scales as large as, or larger than, upper postlabial contacting it 2–5, X= ̄3.89 (2/4 one; 3/4 one; 4/2 one; 4/3 one; 4/4 seven, including holotype; 4 on left side of CNAR 1774; 5/4 one; 5/5 one); scales contacting both upper secondary temporal and upper postlabial 1–3, X= ̄ 2.41 (1/2 two; 2/1 one; 2/2 two; 2/3 one; 2 on left side of CNAR 1774; 3/2 one; 3/3 six, including holotype).
Transverse dorsal scale rows between nuchals and level above vent 51–57, X= ̄ 53.07 (51 four; 52 one [holotype]; 53, four; 54, two; 55, two; 57, one); longitudinal dorsal scale rows around midbody 23–26, X=̄24.43 (23 two; 24 eight, including holotype; 26 four); Toe-IV lamellae 13–15, X= ̄ 13.81 (13/13 three, including holotype; 13/14 one, 14/14 eight;14 on right side, non-recordable on left side, in MZFC-HE 19787; 15/15 one;).
SVL 28.68–65.58, X=̄51.04; SVL / trunk length ratio 1.65–1.96, X=̄1.83; SVL / head length ratio 4.52–5.7, X=̄5.08; SVL / tibia length ratio 8.81–11.94, X=̄9.66.
This paragraph is based on specimens preserved in ethanol and some lines are likely less discernible than in life. Upper secondary dark line extending posteriorly to posterior end of neck in one specimen (CNAR 6585), to forearms in nine (CNAR 1774; MZFC-HE 17503, 19787, 30621–30626), and to posterior end of anterior fourth of body in four (CNAR 24264–24265; MZFC-HE 30620, 30627); dorsolateral light line extending posteriorly to posterior end of anterior fourth of body in four specimens (MZFC-HE 30621, 30623–30625), to midbody in one (MZFC-HE 30622), to hind limbs in one (CNAR 24265), and to anterior portion of tail in eight (CNAR 1774, 6585, 24264; MZFC-HE 17503, 19787, 30620, 30626–30627); lateral light line extending dorsally to sixth scale row at level of mid-neck in 10 specimens (CNAR 1774, 6585, 24264–24265; MZFC-HE 19787, 30621–30622, 30624–30626), and to seventh scale row in four (MZFC-HE 17503, 30620, 30623, 30627).
Remarks. The sample of Plestiodon lotus from near Arcelia, Guerrero (MZFC-HE 19787) is molecularly divergent from the other samples assigned to the species (see above). However, the specimen from Arcelia is not morphologically distinguishable from the other specimens assigned to P. lotus. Furthermore, MZFC-HE 19787 represents the farthest record (ca. 140 km WNW in straight line) from the type locality of P. lotus, which may explain its genetic divergence from other samples. We were not able to obtain molecular data for specimen CNAR 6585, which is geographically intermediate between the specimen from Arcelia and the other sequenced samples of P. lotus. Additionally, photographic records suggest P. lotus is widespread in the Balsas Basin (see below). Thus, it seems likely that the apparent divergence between the sample from Arcelia and the remaining samples of P. lotus is an effect of deficient sampling in areas where P. lotus is expected to occur. Therefore, we provisionally assign the specimen from Arcelia to P. lotus.
Specimens from Morelos assigned to Plestiodon brevirostris brevirostris or regarded as putative intergrades between P. b. brevirostris and P. b. indubitus by Dixon (1969) might represent P. lotus (see Discussion). Unfortunately, those specimens could not be examined.
Etymology. The specific Latin name is treated as a participle in the nominative singular and means bathed, clean, elegant. It makes reference to the appearance of the new species, characterized by having fainter lines than its geographically closest congeners.
Distribution and ecology. Plestiodon lotus is known from 1074–1770 m elevation in the Balsas Basin of the Mexican states of Guerrero, Morelos, Oaxaca, and Puebla. It appears to be widespread in the area and photographic records suggest it may also be present in the vicinities of Amatlán de Quetzalcóatl, northern Morelos, and the Sierra de Nanchititla, western México state.
The specimens of the new species were found in oak and tropical deciduous forests (Fig. 6). Most of them were found under rocks or fallen logs, while some were active on the leaf litter. Plestiodon lotus appears to be more abundant in rocky hillsides with high tree density. Monthly surveys were conducted at the type locality and vicinities, where lizards were only seen between June and February. This suggests a reduction in activity in the warmer months (March to May) associated with the dry season. Vegetation at the type locality is oak forest, where Quercus glaucoides, Q. castanae, and Q. magnoliifolia dominate the arboreal stratum. Climatic variables extracted from BioClim (Hijmans et al. 2005) are as follows: mean annual temperature is 22.7°C, mean temperatures of the warmest and coldest quarter are 25.2°C and 20.1°C, respectively, and the mean annual precipitation is 885 mm.
There is no direct evidence that Plestiodon lotus is sympatric with other species of the genus. Seven other species of Plestiodon are found in Guerrero, Morelos, Oaxaca, and Puebla, but they differ from P. lotus in elevational range and/or are distributed in different biogeographic provinces (Fig. 7). Plestiodon brevirostris is found in mesic forest and xeric scrub at higher elevations of the Sierra Madre del Sur, the Transmexican Volcanic Belt, and the biogeographically complex intersection of this Belt with the Sierra Madre Oriental; P. copei and P. indubitus inhabit mesic forests at higher elevations of the Transmexican Volcanic Belt, though P. indubitus is found fairly low in the Sierra de Taxco and the vicinities of Tepoztlán and Cuernavaca, where it probably comes into contact with P. lotus; P. lynxe lynxe inhabits a variety of habitats at usually higher elevations of the Central Mexican Plateau, Sierra Madre Occidental, Sierra Madre Oriental, and Transmexican Volcanic Belt; P. nietoi is found in mesic forest at higher elevations of the Sierra Madre del Sur; P. ochoterenae inhabits similar elevations to P. lotus in the Sierra Madre del Sur and both species probably come into contact in the continental slopes of the aforementioned sierra (e.g., near Chilapa de Álvarez, Guerrero); and P. sumichrasti is found in tropical forest at lower elevations of the Veracruzan province (Feria Ortiz 2011; Feria-Ortiz et al. 2011; Feria-Ortiz & García- Vázquez 2012; Lee 2000; Pavón-Vázquez, pers. obs.). The skink Marisora brachypoda (Taylor) is found in sympatry with P. lotus at the type locality and near Santiago Tamazola, Oaxaca—and presumably in other localities—but differs in microhabitat preference favoring more open areas. Mesoscincus altamirani (Dugès) is another skink that might be sympatric with P. lotus in Guerrero (Mendoza Hernández et al. 2011; Jiménez-Arcos et al. 2016).
description: Published as part of Pavón-Vázquez, Carlos J., Oca, Adrián Nieto-Montes De, Mendoza-Hernández, Andrés A., Centenero-Alcalá, Eric, Santa Cruz-Padilla, Samuel A. & Jiménez-Arcos, Víctor H., 2017, A new species of Plestiodon (Squamata: Scincidae) from the Balsas Basin, Mexico, pp. 149-172 in Zootaxa 4365 (2) on pages 156-162, DOI: 10.11646/zootaxa.4365.2.3, http://zenodo.org/record/1117522