Stenocercus philmayi, Venegas & García-Ayachi & Chávez-Arribasplata & Chávez & Wong & García-Bravo, 2020

Venegas, Pablo J., Garcia-Ayachi, Luis A., Chavez-Arribasplata, Juan C., Chavez, German, Wong, Ivan & Garcia-Bravo, Antonio, 2020, Four new species of Stenocercus Dumeril & Bibron, 1837 (Squamata, Iguania) from the Department of Amazonas in northeastern Peru, Evolutionary Systematics 4 (2), pp. 79-108 : 79

Stenocercus philmayi sp. nov. Figs 13 , 14

Type material.

Holotype:

PERU • ♂, adult; Amazonas Department, Luya Province, Pisuquía District, Las Corontas; 6°28.54'S, 78°8.77'W; 1340 m a.s.l.; 15 Dec. 2019; I. Wong and A. García-Bravo leg.; CORBIDI 21092.

Paratypes:

PERU • 1 ♀, adult, 1 juvenile; collected with the holotype; CORBIDI 21090, 21093 • 2 ♂, adults, 2 juveniles; Amazonas Department, Luya Province, Pisuquía District, Las Corontas; 6°28.75'S, 78°8.52'W; 1470 m a.s.l.; 13 Dec. 2019; I. Wong and A. García-Bravo leg.; CORBIDI 21074, 21078, 21075, 21087 • 1 ♂, adult; Amazonas Department, Luya Province, Pisuquía District, Las Corontas; 6°28.79'S, 78°8.61'W; 1390 m a.s.l.; 13 Dec. 2019; I. Wong and A. García-Bravo leg.; CORBIDI 21077.

Diagnosis.

Stenocercus philmayi sp. nov. differs from other species of Stenocercus except for S. aculeatus , S. angulifer , S. catherineae sp. nov., S. dracopennatus sp. nov., S. huancabambae , S. prionotus , and S. scapularis by having: (1) projecting-angulate temporals, (2) laterally oriented nostrils; (3) dorsal and lateral scales of body similar in size, and (3) scales on posterior surface of thighs keeled and imbricate. Stenocercus aculeatus , S. angulifer and S. scapularis differs from S. philmayi sp. nov. by having a dorsolateral crest (absent in S. philmayi sp. nov.). Stenocercus prionotus and S. philmayi sp. nov. share a prominent vertebral crest, however the former lacks a postfemoral mite pocket (present in S. philmayi sp. nov.). Adult males of S. aculeatus and S. angulifer can be easily distinguished from S. philmayi sp. nov. by having the gular region covered by a black patch (absent in the new species) and fewer gulars (15 to 18 in S. aculeatus and 16 to 20 in S. angulifer versus 20 to 24 in S. philmayi sp. nov.). The new species differs from S. scapularis by having fewer scales around midbody (34 to 45 in S. philmayi sp. nov. versus 52 to 70 in S. scapularis according with Torres-Carvajal (2007b)).

The new species shares the presence of two canthals with the geographically close S. catherineae sp. nov. and S. dracopennatus sp. nov. (all from the northern extreme of the central Andes in the Department of Amazonas). However, S. philmayi sp. nov. possesses conspicuously larger dorsal scales than S. catherineae sp. nov., resulting in 32 to 38 vertebrals and 34 to 45 scales around midbody (43 to 53 vertebrals and 46 to 59 scales around midbody in S. catherineae sp. nov.). Adult males of S. catherineae sp. nov. have a black patch covering most of the gular region (Fig. 2B, D ) and S. huancabambae has a black elongate or circular patch covering the ventral surface of the neck (Fig. 4B ), and both species share a pink coloration on the belly and the base of the tail (Fig. 2B , 4B ); whereas the new species lacks a black or pink coloration on ventral surfaces (Fig. 14B, D ). Additionally, S. huancabambae possesses a very strongly compressed tail laterally compared to the compressed tail of S. philmayi sp. nov. In the case of S. dracopennatus sp. nov., it can be distinguished from S. philmayi sp. nov. (character state in parentheses) by having three occipitals (one), a black patch on the ventral surface of neck in adult males (dark coloration absent on ventral surface), and strongly keeled scales on the belly (keeled).

Definition.

(1) Maximum SVL in males 95 mm (n = 4); (2) SVL in females 74 mm (n = 1); (3) vertebrals 32-38; (4) paravertebrals 49-59; (5) scales around midbody 34-45; (6) supraoculars 4-5; (7) internasals 3-5; (8) postrostrals 2-4; (9) loreals 4-6; (10) gulars 20-24; (11) subdigitals on Finger IV 18-21; (12) subdigitals on Toe IV 28-31; (13) posthumeral mite pocket present as a deep depression with a narrow opening [Type 3 of Torres-Carvajal (2007b)]; (14) postfemoral mite pocket present as a distinct pocket with a posteroventrally oriented slit-like opening [Type 2 of Torres-Carvajal (2007b)]; (15) parietal eye not visible through interparietal cornea in any specimens (n = 8); (16) scales on occipitoparietal region large, keeled, not imbricate; (17) projecting, angulate temporals present; (18) row of enlarged supraoculars occupying most of supraocular region present; (19) scales on frontonasal region not imbricate; (20) preauricular fringe present, distinct; (21) neck folds absent; (22) lateral and dorsal nuchals similar in size; (23) posterior gulars rhomboidal, projected posteriorly, keeled and conspicuously imbricate, not notched; (24) lateral and dorsal body scales similar in size; (25) vertebrals larger than adjacent paravertebrals, forming a prominent vertebral crest; (26) dorsolateral crest absent; (27) ventrals keeled, imbricate, not mucronate; (28) scales on posterior surfaces of thighs keeled, imbricate, mucronate; (29) inguinal granular pocket absent; (30) inguinal groove absent; (31) preanals projected; (32) tail compressed laterally in adult males; (33) tail length 71-72% of total length; (34) caudal whorls per autotomic segment three; (35) caudals not spinose; (36) dark brown stripe extending anterodorsally from subocular region to supraciliaries absent; (37) dark patch extensively covering gular region of females absent; (38) dark patch covering gular region in adult males absent; (39) black patch on ventral surface of neck in adult males absent; (40) dark midventral longitudinal mark such as faint line, conspicuous stripe, or extensive patch in adult males absent; (41) dark patches on ventral surface of thighs in adult males absent; (42) two xiphisternal and three postxiphisternal pairs of inscriptional ribs fused medially, forming three chevrons (Pattern 6A of Torres-Carvajal 2004).

Description of the holotype.

Male (Fig. 13 ); SVL 95 mm; TL 246 mm; maximum head width 17.5 mm; head length 22.5 mm; head height 15.4 mm; parietals, interparietals and postparietals large, parietals rugose and the rest of scales keeled, not imbricate; occipitals three, small, keeled; parietal eye not visible; supraoculars in five rows, keeled, slightly imbricate, subequal in size; canthals two; canthal in contact with the nasal; scales on frontonasal region slightly imbricate, keeled; internasals four; postrostrals four, both wider than long; supralabials five; infralabials six; loreals five; lorilabials in one row; preocular one, in contact with second canthal; lateral temporals keeled, imbricate; gulars in 20 rows between tympanic openings; all gulars keeled, imbricate, apical pit absent; second infralabial not in contact with second and third sublabials; mental in contact with first pair of infralabials; lateral and dorsal scales of body and neck keeled, imbricate, mucronate; lateral and dorsal body scales similar in size; scales around midbody 40; vertebrals larger than dorsals, 35 scales on vertebral row, prominent serrate vertebral crest present; paravertebrals 59; ventrals broad, rhomboidal, keeled, imbricate; preauricular fringe short, composed of four enlarged scales, all similar in size; antegular, gular, postauricular, oblique, supraauricular, longitudinal and antehumeral neck folds absent; limb scales keeled, imbricate, mucronate; ventral scales of hindlimbs and upper arms keeled and mucronate; lamellae on Finger IV 18; lamellae on Toe IV 31; tail compressed laterally; caudals keeled, imbricate, mucronate; basal subcaudals strongly keeled, imbricate; tail length 3.42 times SVL; posthumeral mite pocket present as a deep depression with a narrow opening; postfemoral mite pocket present as a distinct shallow pocket with a posteroventrally oriented slit-like opening; postfemoral region composed of imbricate, keeled scales.

Coloration in life

(Fig. 14A, B ). Dorsal surface of body greenish gray with dark brown chevrons and narrow greenish white interspaces over the vertebral line; body flanks dusty brown splattered with whitish dots; dorsal surface of limbs olive green with scattered faint brown specks; dorsal surface of tail dusty brown with the crest greenish cream and faint cream transversal stripes; dorsal surface of head pale green with some scattered cream dots; sides of head greenish cream with the ocular region dark green; sides of neck greenish cream as the sides of head. Ventrally, gular region pale greenish cream; neck and chest paler than gular region; belly and tail cream with a tan hue; pelvic region pale cream and hindlimbs tan. The iris is dark brown.

Coloration in preservative

(Fig. 13D, E ). Similar to the life coloration however the greenish hue on the dorsum is pale brown and dorsal surface of the head is dark gray. Ventrally, gular region and chest dusty gray with a bluish hue, the rest of body is dark tan with the pelvic region dark cream.

Intraspecific variation.

Measurements and scutellation of Stenocercus philmayi sp. nov. are presented in Table 1 . Second infralabial not in contact with third sublabial in any specimens, and first pair of postmentals not in contact medially in one specimen. The other adult male paratypes (n = 3) are identical to the holotype (Fig. 14C, D ). Two juvenile males (CORBIDI 21087 and 21075) have the same dorsal pattern as adults (Fig. 14G ) However, the dorsal surface of the head is brown, the greenish hue of the sides of head, neck and forearms is absent, and they possess a cream dorsolateral stripe that extends from the loreal region to the scapular region in CORBIDI 21087 and to the base of tail in CORBIDI 21075. Ventrally juvenile males are cream with scattered elongate pale gray blotches on neck, chest and sides of belly. The single hatchling paratype (CORBIDI 21093) has the dorsal surface dark brown with narrow black chevrons over the vertebral line and a longitudinal cream stripe from the loreal region to the scapular region (Fig. 14H ). The dorsal surface of the hindlimbs also presents thin black bars. Ventral surface is cream without marks.

Sexual dimorphism is evident in adults. Dorsal coloration in a single female paratype (CORBIDI 21090) is dark brown with thin darker brown chevrons and darker thin brown bars on hindlimbs (Fig. 14E, F ). Also present a longitudinal cream stripe from the loreal region to scapular region becoming faint from the temporal region. Ventral surface is completely cream without marks.

Distribution and natural history observations.

Stenocercus philmayi sp. nov. is only known from Las Corontas in the northern portion of the central Andes at elevations of 1340-1470 m within the Río Marañón basin (Fig. 5 ). According to the terrestrial ecoregions of the world by Olson et al. (2001), this species inhabits the Marañón dry forests ecoregion and following the ecoregions of Brack-Egg (1986), the equatorial dry forest ecoregion. The general landscape in the habitat of S. philmayi sp. nov. is the ecotone between dry forest and humid montane forest. The dry forest in this zone has high trees with a canopy between 4 and 6 m, dense understory vegetation and scattered patches of cacti. Individuals of S. philmayi sp. nov. were observed during sunny days between 800 and 1400 hours basking on fallen logs close to trails that border or cross patches of forest. One adult male specimen was collected basking in the understory vegetation at 1 m in height. Other individuals were observed basking on rocks in patches of cacti and also on rocky fences with bushes near houses. Additional squamate reptile species collected with S. philmayi sp. nov. were Ameiva aggerecusans Koch, Venegas, Rödder, Flecks & Böhme, 2013, Microlophus stolzmanni Steindachner, 1891, Phyllodactylus pachamama Koch, Flecks, Venegas, Bialke, Valverde & Rödder, 2016, Epictia septemlineata Koch, Venegas & Böhme, 2015, and E. antoniogarciai Koch, Venegas & Böhme, 2015.

Cadle (2001), reported an undescribed species of Stenocercus (represented by a single specimen), from 17 km ENE of Balsas village (6°49.00'S, 78°0.00'W) (Fig. 4 ) with similar features to S. philmayi sp. nov. The location of this specimen is 40.5 km to the south of the type locality of S. philmayi sp. nov. at an elevation of 1477 m, and lies also in the Marañón dry forests ecoregion.

The single female paratype collected during the rainy season (December 2019) had 2 eggs, one in the left and one in the right ovary. The sizes of these follicles are 19.71 × 9.44 mm and 19.81 × 8.40 mm; their volumes were 919.6 mm³ and 731.8 mm³, respectively.

Etymology.

The specific epithet philmayi is a noun in the genitive case and is a patronym for Philip May (1946-2017), an American lichenologist and philanthropist, who was passionate about protecting biological diversity. During his life-time, his generous support of Nature and Culture International was instrumental to the protection of endangered ecosystems and endemic species in the Amazonas, Cajamarca, and La Libertad departments of Peru. Even after his death in 2018, his generosity has continued to protect Latin America’s biodiversity through charitable bequests. This new species was discovered in one of the departments that May supported during his life, and naming it after him, honors May’s enduring legacy as a champion of biodiversity.

Figures

Figure 2. Dorsolateral and ventral views of Stenocercus catherineae sp. nov. in life: (A, B) holotype, adult male, SVL 82 mm (CORBIDI 21365); (C, D) adult male, SVL 79 mm (CORBIDI 21366); (E, F) adult female, SVL 75 mm (CORBIDI 21367); (G, H) adult female, SVL 75 mm (CORBIDI 501). Photographs by Pablo J. Venegas.

Figure 4. Dorsolateral and ventral views of adult males of three species of Stenocercus: (A, B) S. huancabambae, (C, D) S. aculeatus, (E, F) S. prionotus from northern-central Peru, and (G, H) S. prionotus from southern Peru. Photographs by: (A - D) Pablo J. Venegas, (E) Andy Barboza, (F) Diego Vasquez, and (G, H) German Chavez.

Figure 5. Distribution map of S. catherineae sp. nov. (red triangles), S. dracopennatus sp. nov. (yellow star), and S. philmayi sp. nov. (blue squares), and the similar species: S. aculeatus (fuchsia diamonds), S. angulifer (blue diamonds), S. huancabambae (orange diamonds), S. prionotus (turquoise diamonds), and S. scapularis (red diamonds). Symbols with a dot in the middle correspond to type localities. White circles with a dot are important cities for reference.

Figure 13. Stenocercus philmayi sp. nov. preserved holotype, adult male, SVL 95 mm (CORBIDI 21092): dorsal (A), lateral (B), and ventral (C) views of the head; dorsal (D) and ventral (E) views of the entire specimen. Photographs by Luis A. Garcia-Ayachi. Scale bars: 10 mm.

Figure 14. Dorsolateral and ventral views of Stenocercus philmayi sp. nov. in life: (A, B) holotype, adult male, SVL 95 mm (CORBIDI 21092); (C, D) adult male, SVL 86.0 mm (CORBIDI 21077); (E, F) adult female, SVL 74 mm (CORBIDI 21090); (G) juvenile male, SVL 55 mm (CORBIDI 21075); and (H) hatchling, SVL 33 mm (CORBIDI 21093). Photographs by Ivan Wong.