Pholidobolus samek, Parra & Nunes & Torres-Carvajal, 2020

Parra, Vanessa, Nunes, Pedro M. Sales & Torres-Carvajal, Omar, 2020, Systematics of Pholidobolus lizards (Squamata, Gymnophthalmidae) from southern Ecuador, with descriptions of four new species, ZooKeys 954, pp. 109-156 : 109

Pholidobolus samek sp. nov. Figures 4 , 5 , 6 Proposed standard English name: Green-striped cuilanes Proposed standard Spanish name: Cuilanes de franjas verdes

Holotype.

QCAZ 14955 (Figs 4 , 5 ), adult male, Ecuador, Provincia Zamora-Chinchipe, Cerro Plateado Biological Reserve, Cerro Plateado plateau, 4.6159S, 78.7870W, WGS84, 2844 m, 23 September 2016, collected by Diego Almeida, Eloy Nusirquia, Fernando Ayala, Javier Pinto, Alex Achig and Malki Bustos.

Paratypes (6).

Ecuador: Provincia Zamora-Chinchipe: QCAZ 14954 (adult female), same data as holotype; QCAZ 14956 (adult female), Cerro Plateado Biological Reserve, 4.6050S, 78.8167W, WGS84, 2320 m, 28 September 2016; QCAZ 14969-70, 14976-77(hatchlings) Cerro Plateado Biological Reserve, 4.6179S, 78.7838W, WGS84, 2873 m, 24 September 2016, same collectors as holotype.

Diagnosis.

Pholidobolus samek is unique among its congeners, except P. condor sp. nov., in having green dorsolateral stripes on the head. However, adult males of P. samek differ from those of P. condor sp. nov. in having brighter dorsolateral head stripes and lacking a reddish venter. In addition, P. affinis , P. prefrontalis , P. macbrydei , P. dolichoderes sp. nov., and P. montium differ from P. samek (character states of P. samek in parentheses) in having a loreal scale frequently in contact with the supralabials (loreal scale not in contact with supralabials), and dorsal scales finely wrinkled (slightly keeled). Pholidobolus ulisesi and P. hillisi differ from P. samek in having a diagonal white bar along the rictal region (white rictal bar absent). Pholidobolus samek can be distinguished from P. dicrus by lacking a bifurcating vertebral stripe at midbody. Pholidobolus affinis , P. prefrontalis , P. dicrus , P. hillisi , and P. vertebralis further differ from P. samek in having well defined prefrontal scales (if present, prefrontal scales poorly differentiated). Additionally, P. samek has fewer dorsal scales (27-29) than P. affinis (45-55), P. montium (35-50), P. prefrontalis (37-46), P. macbrydei (31-43), P. fascinatus sp. nov. (32-37), and P. dolichoderes sp. nov. (35-40). Pholidobolus samek can be further distinguished from P. fascinatus by having widened medial scales on collar, and from P. dolichoderes sp. nov. by having fewer temporals (4-5 and 7-9, respectively), fewer ventrals (19-21 and 25-27), and fewer gulars (15-18 and 22-23).

Characterization.

(1) Two (rarely three) supraoculars, anteriormost slightly larger than posterior one; (2) prefrontals present or absent; (3) femoral pores absent in both sexes; (4) four to five opaque lower eyelid scales; (5) scales on dorsal surface of neck striated, becoming slightly keeled from forelimbs to tail; (6) two or three rows of lateral granules at midbody; (7) 27-29 dorsal scales between occipital and posterior margin of hindlimb; (8) lateral body fold present; (9) keeled ventrolateral scales on each side absent; (10) dorsum grayish brown with a distinct golden gray middorsal stripe, slender at midbody, becoming pale gray towards tail; (11) labial stripe white or orange; (12) flanks of body dark brown; (13) conical hemipenial body, with sulcus spermaticus originating between thick lips.

Description of holotype.

Adult male (QCAZ 14955) (Figs 4 , 5 ); SVL 46.7 mm; TL 80.9 mm; dorsal and lateral head scales juxtaposed, finely wrinkled; rostral hexagonal, 2.06 times as wide as high; frontonasal irregularly quadrangular, wider than long, laterally in contact with nasal, loreal and first superciliary, slightly bigger than frontal; prefrontal scales absent; frontal longer than wide, in contact with one supraocular on the left side, and two on the right side; frontoparietals pentagonal, longer than wide, slightly wider posteriorly, each in contact laterally with supraocular II; interparietal roughly heptagonal; parietals slightly bigger than interparietal, hexagonal, and positioned anterolaterally to interparietal, each in contact anteriorly with supraocular II (and supraocular III on right side) and dorsalmost postocular; postparietals three, medial scale smaller than laterals; seven supralabials, fourth one longest and below center of eye; six infralabials, fourth one shortest and below center of eye; temporals enlarged, irregularly hexagonal, juxtaposed, smooth; two large supratemporal scales, smooth; nasal slightly divided, irregularly pentagonal, longer than high, in contact with rostral anteriorly, first and second supralabials ventrally, frontonasal dorsally, loreal posterodorsally and frenocular posteroventrally; nostril on ventral aspect of nasal, directed lateroposteriorly; loreal rectangular, wider dorsally; frenocular higher than long, in contact with nasal, separating loreal from supralabials; two supraoculars on left side, three on right side (posteriormost much smaller), with the first one being the largest; four elongate superciliaries, first one enlarged, in contact with loreal; palpebral disc divided into four enlarged, pigmented scales; suboculars three (on the left side the medial subocular is fragmented), elongated and homogeneous in size; two postoculars, the dorsalmost wider than the other; ear opening vertically oval, without denticulate margins; tympanum recessed into a shallow auditory meatus; mental semicircular, wider than long; postmental pentagonal, slightly wider than long, followed posteriorly by three pairs of genials, the anterior two in contact medially and the posterior one separated by postgenials; all genials in contact with infralabials; gulars imbricate, smooth, posteriorly widened in two longitudinal rows; posterior row of gulars (collar) with six scales, the medial two widened.

Nuchal scales similar in size to dorsals, except for the anteriormost that are widened; scales on sides of neck small and granular; dorsal scales hexagonal, elongate, imbricate, arranged in transverse rows; scales on dorsal surface of neck striated, becoming progressively keeled from forelimbs to tail; number of dorsal scales between occipital and posterior margin of hindlimbs 27; dorsal scale rows in a transverse line at midbody 26; one longitudinal row of smooth, enlarged ventrolateral scales on each side; dorsals separated from ventrals by two rows of small scales at level of 13th row of ventrals; lateral body fold between fore and hindlimbs present; ventrals smooth, wider than long, arranged in 20 transverse rows between collar fold and preanals; six ventral scales in a transverse row at midbody; subcaudals smooth; axillary region with granular scales; scales on dorsal surface of forelimb striated, imbricate; scales on ventral surface of forelimb granular; two thick, smooth thenar scales; supradigitals (left/right) 3/3 on finger I, 6/7 on II, 8/8 on III, 9/9 on IV, 6/6 on V; supradigitals 3/4 on toe I, 6/6 on II, 10/9 on III, 11/12 on IV, 7/7 on V; subdigital lamellae of fingers I and II single, paired on III (except the four distalmost), paired at base on IV, on finger V all single; subdigital lamellae 5/5 on finger I, 11/12 on II, 15/16 on III, 17/16 on IV, 9/10 on V; subdigital lamellae on toes I and II single, on toe III, IV and V all paired, except for the three distalmost subdigitals; subdigital lamellae 6/6 on toe I, 11/10 on II, 16/15 on III, 21/21 on IV, 14/14 on V; groin region with small, imbricate scales; scales on dorsal surface of hindlimbs smooth and imbricate; scales on ventral surface of hindlimbs smooth; scales on posterior surface of hindlimbs granular; femoral pores absent; preanal pores absent; cloacal plate paired, bordered by four scales anteriorly, of which the two medialmost are enlarged.

Additional measurements (mm) and proportions of the holotype: HL 11.4; HW 7.4; ShL 7.0; AGD 23.9; TL/SVL 1.5; HL/SVL 0.2; HW/SVL 0.2; ShL/SVL 0.1; AGD/SVL 0.5.

Color of holotype in life.

Dorsal background from head to base of tail grayish brown, with a golden light brown vertebral stripe extending from occiput to tail; bright green dorsolateral stripes on head; cream white longitudinal stripe extending from first supralabial to shoulder; sides of neck, flanks and limbs dark brown; reddish brown narrow stripe extending from tympanum to arm insertion; ventrolateral region of body grayish brown; throat cream; chest, belly and base of tail cream orange (Figs 4C , 6B ).

Color of holotype in preservative.

Dorsal background uniformly grayish brown, with a golden-gray vertebral stripe extending from occiput to tail; vertebral stripe wider anteriorly, becoming slightly slender at most posterior part of body; dorsal and lateral surfaces of head brown (rostral, frontonasal, frontal, frontoparietals, and supraoculars); bluish white longitudinal stripe extending from first supralabial to shoulder and fading on flanks; ventrolateral aspect of neck dark brown with a dorsolateral light brown stripe extending posteriorly along flanks to hindlimbs; forelimbs with scattered ocelli (black with white center); flanks grayish brown with two dorsolateral stripes on each side, the dorsal one dark brown and the most ventral one brown diffuse with dark brown spots; tail brown dorsally; ventral surface of head gray, chest and venter dark gray, ventral surface of tail slightly gray, with scattered dark brown marks.

Variations.

Measurements and scale counts of Pholidobolus samek are presented in Table 6 . Supralabials 8/7 (left/right) and temporals five in specimen QCAZ 14956; small and separated prefrontals on both sides in QCAZ 14954 and one prefrontal on right side in QCAZ 14956; little intrusive scales between parietal and postparietal in QCAZ 14954; frontal hexagonal in QCAZ 14956; roughly decagonal interparietal in QCAZ 14954. Usually two scales on posterior cloacal plate, four in QCAZ 14954 and 14956. Male is larger (SVL 46.7 mm, N = 1) than females (maximum SVL 45.4 mm, N = 2). Hatchlings (QCAZ 14969, 14970, 14976) with eight or seven (QCAZ 14976) posterior gular (collar) scales. Unlike the male holotype, females have an orange-brown longitudinal stripe extending from third supralabial to shoulder and fading on the flanks (Fig. 6 ).

Distribution and natural history.

Pholidobolus samek inhabits cloud forests in Cordillera del Cóndor, southeastern Ecuador at elevations between 2324-2844 m (Fig. 7 ). The new species is known only from Zamora-Chinchipe province, on the sandstone plateaus of Cerro Plateado Biological Reserve. The ground at the type locality is covered with mosses, roots, and bromeliads. Such ground cover is locally known as bamba. All specimens were found active at 11h30-17h00 under stones or terrestrial bromeliads (Fig. 8 ). Four eggs, collected under flat stones on 24-09-2016, were incubated in sphagnum and perlite in captivity for two months approximately. They were 14.0-14.1 mm long, 8.0-8.5 mm wide, and weighted 0.4 g on average. Hatchlings (QCAZ 14969-70, 14976-77) weighted 0.3 g and were 24.7 mm in SVL on average.

Conservation status.

Pholidobolus samek is only known from Cordillera del Cóndor. The population size for this species is unknown, but our sampling suggests low abundances. Because of the small known distribution, as well as habitat destruction through mining activities nearby ( Van Teijlingen 2016), we suggest assigning P. samek to the Critically Endangered category under criteria B1a, b(iii); C1; D, according to IUCN (2012) guidelines.

Etymology.

The specific epithet samek means green in the Shuar language, in allusion to the green dorsolateral head stripes distinguishing the new species from other congeners. The type locality of Pholidobolus samek lies within territory of Shuar indigenous people, who inhabit the Amazonian rainforest in Ecuador and Peru.

Remarks.

Pholidobolus samek sp. nov. is very similar morphologically and genetically to P. condor sp. nov. These species can be easily distinguished from each other by coloration in adult males, although we recognize that our sample size is small (N = 7 and 4, respectively) and includes only one adult male per species. However, further evidence supports recognition of P. samek and P. condor as different species. First, they are reciprocally monophyletic and they are not sister taxa, with P. samek being sister to " P. macbrydei " Clade A (Fig. 1 ), which is very different in color patterns from either P. samek or P. condor (V. Parra and O. Torres-Carvajal, personal observation). Second, unlike the 12S gene (the less variable gene in this study), genetic distances between P. samek and P. condor for 16S and ND4 are not the lowest (Tables 2 and 4 , respectively) within Pholidobolus . For example, the 16S distance between P. samek and P. condor (3%) is the same as the distance between the well-recognized species P. paramuno and P. affinis . In addition, genetic exchange among P. samek , P. condor and Clade A is very unlikely as they are isolated from each other on mountaintops above 2000 m (Fig. 7 ).

Figures

Figure 1. Phylogeny of Pholidobolus. Maximum clade credibility tree derived from a partitioned analysis of 1904 bp of mitochondrial and nuclear DNA. Bayesian posterior probabilities are shown above branches and bootstrap values (RAxML analysis) below branches; values ≤ 0.5 and 50, respectively, are not shown. For clarity, outgroup taxa and values on short branches are not shown. Species outside the " P. macbrydei " complex are in grey; new species described in this paper are in color matching the distribution records of the map in Figure 7. The species name followed by voucher number and province (" P. macbrydei " complex only) are provided for each terminal. Photographs from top to bottom: P. dolichoderes sp. nov. holotype, P. fascinatus sp. nov. holotype, " P. macbrydei " (Clade B) QCAZ 15824, P. samek sp. nov. holotype, P. condor sp. nov. holotype.

Figure 4. Holotype of Pholidobolus samek sp. nov. (QCAZ 14955) in dorsal (A), ventral (B), and lateral (C) views. Male, SVL = 46.7 mm. (A, B): preserved specimen; (C): live specimen. Photographs by Darwin Nunez and Valeria Chasiluisa.

Figure 5. Head of holotype of Pholidobolus samek sp. nov. (QCAZ 14955) in lateral (A), dorsal (B), and ventral (C) views. Photographs by Valeria Chasiluisa. Scale bar: 5 mm.

Figure 6. Pholidobolus samek sp. nov. in life. A Adult female, paratype (QCAZ 14954) B adult male, holotype (QCAZ 14955).

Figure 7. Distribution of samples of the " Pholidobolus macbrydei " species complex included in phylogenetic analyses. Circles correspond to four new species described in this paper: P. samek sp. nov. (red), P. condor sp. nov. (blue), P. dolichoderes sp. nov. (brown), and P. fascinatus sp. nov. (green). Triangles are " Pholidobolus macbrydei " clades as illustrated in the phylogenetic tree (Fig. 1): A (green) B (white) C (red) D (blue) E (black) F (turquoise). Orange diamond corresponds to type locality of P. macbrydei. This map was created in QGIS v 3.10.

Figure 8. Habitat of Pholidobolus samek sp. nov. A Vegetation around type locality, Cerro Plateado Biological Reserve, Ecuador B habitat where holotype was found. Photographs by Alvaro Perez.