Stenocercus nigrobarbatus VENEGAS, ECHEVARRÍA, GARCÍA-AYACHI & LANDAURO, 2020
Can you confirm these amateur observations of Stenocercus nigrobarbatus?
|Higher Taxa||Tropiduridae, Iguania, Sauria, Squamata (lizards)|
|Synonym||Stenocercus nigrobarbatus VENEGAS, ECHEVARRÍA, GARCÍA-AYACHI & LANDAURO 2020|
Type locality: Fundición (12°17’36.41”S, 74°39’39.67” W) at 2,158 m asl, Tayacaja Province, Huancavelica Region, Peru
|Types||Holotype. CORBIDI 13725, adult male, collected on January 31, 2014 by L. Y. Echevarría.|
Paratypes. Peru: Huancavelica Department: Tayacaja Province: CORBIDI 13637 a juvenile female from Jatuspata (12°15’14.617’’ S, 74°41’ 16.93’’ W) at 2,972 m asl, collected on September 3, 2013 by C. Landauro; CORBIDI 13638 a juvenile female from Pichiu (12°19’11.815’’ S, 74°39’3.588’’ W) at 2,036 m asl, collected on September 13, 2013 by C. Landauro; CORBIDI 13640 juvenile female from Pichiu, collected on September 12, 2013 by C. Landauro; CORBIDI 13641 adult female from Barropata (12°17’21.943’’ S, 74°41’19.035’’ W) at 1,725 m asl, collected on October 2, 2013 by C. Landauro; CORBIDI 13639 and CORBIDI 13642 female juveniles from Fundición (12°17’32.347’’ S, 74°39’45.433’’ W), at 2,169 m asl, collected on September 28, 2013 by C. Landauro; CORBIDI 13718 adult male from Chupto (12°19’52.96” S, 74°39’13” W) at 2,058 m asl, collected on January 23, 2014 by L. Y. Echevarría; CORBIDI 13719 adult male from Chupto (12°18’22.19” S, 74°39’18.42” W) at 2,314 m asl, on January 24, 2014 by L. Y. Echevarría; CORBIDI 13722 adult female from Chupto (12°19’52.96” S, 74°39’13” W) at 2,058 m asl, collected on January 21, 2014 by L. Y. Echevarría; CORBIDI 13728 adult female from Barropata (12°17’34.95” S, 74°41’34.08” W) at 1,704 m asl, collected on February 2, 2014 by L. Y. Echevarría; CORBIDI 13729 adult female from Barropata (12°17’22.11” S, 74°41’19.07” W) at 1,783 m asl, collected on February 3, 2014 by L. Y. Echevarría; CORBIDI 14669 adult female from Chupto (12°18’48.18” S, 74°39’1.83” W) at 2,345 m asl, collected on July, 1 2014 by L. Y. Echevarría; CORBIDI 14674 adult female from type locality, collected on July 6, 2014 by L. Y. Echevarría; CORBIDI 14676 juvenile female and CORBIDI 14677 adult male from Barropata (12°17’37.66” S, 74°41’39.18” W) at 1,693 m asl, collected on July 7, 2014 by L. Y. Echevarría; CORBIDI 15765–66 (adult male and female, respectively) and CORBIDI 15767 (juvenile male) from Pichiu (12°15’31.57” S, 75°6’3.6” W) at 2,206 m asl, collected on January 14, 2015 by L. Lujan; CORBIDI 16033 adult male from Pichiu (12°19’50” S, 74°39’13.07” W) at 2,090 m asl, collected on July 9, 2015 by J. Malqui; CORBIDI 20546–47 two adult males from San Luis de Estanque (12o19’8.62” S, 74o44’24.19” W) at 2,636 m asl., collected on Jun 17, 2019 by L.A. García-Ayachi.
|Diagnosis||Diagnosis: Adult males of Stenocercus nigrobarbatus can be easily distinguished from all species of Stenocer- cus by having a continuous black patch covering the infralabials, throat, chest, ventral surfaces of forelimbs, belly (as a black midventral line), ventral surfaces of hind limbs, and pelvic region (Figs. 6B, 8B, 9B and 9C).|
However, among the 69 currently described species of Stenocercus, S. nigrobarbatus resembles S. frittsi Tor- res-Carvajal, 2005, and S. variabilis Boulenger, 1901, by the following combinations of characters: (1) granular scales on the posterior surface of thighs, (2) imbricate and keeled lateral body scales, (3) a distinct row of enlarged vertebral scales, (4) unnotched gular scales, (5) three caudal whorls per autotomic segment, (6) brown dorsal ground color, and (7) distinct oblique neck fold, and antegular fold not continuous medially.
Stenocercus nigrobarbatus differs from the geographically close S. frittsi (character state of latter in parenthesis) by having a postfemoral mite pocket composed by one or more vertical folds or ridges, Type 1 of Torres-Carvajal (2007a) (postfemoral pocket absent in S. frittsi), 2–4 postrostrals (5–7), and two pairs of postxiphisternal inscrip- tional ribs, long, not in contact midventrally, pattern 1A of Torres-Carvajal (2004) (three pairs of postxiphisternal inscriptional ribs, two pairs long and the last pair short, not in contact midventrally; pattern 2B of Torres-Carvajal 2004).
Stenocercus nigrobarbatus can be distinguished from S. variabilis (character state in parenthesis) by having 2–4 postrostrals (6), postfemoral pocket composed by one or more vertical folds or ridges, Type 1 of Torres-Carva- jal (2007a) (slit-like opening, Type 2 of Torres-Carvajal 2007a), and inguinal groove absent (present). In addition, lateral body scales in S. nigrobarbatus are slightly smaller than dorsals, while S. frittsi and S. variabilis have lateral body scales approximately half the size of dorsals.
Color in life of the holotype. Dorsal surfaces of head and neck cinnamon brown with yellow spots, denser on neck; lorilabials and supralabials yellow; infralabials black; ventrolateral regions of head and neck black; dorsal surfaces of body, limbs and tail dusty brown with pale yellow spots; flanks light blue, densely covered with cream spots; limbs and tail with thin dark brown marks on dorsal surfaces (Fig. 8A). Ventral surface of head, throat, chest black; ventral surfaces of forelimbs black, although pigmentation is faint at elbow joint; a bold black midventral line, continuous with chest pigmentation, flanked by pink; ventral surfaces of hind limbs, and pelvic region black, except by the cloaca; posterior surfaces of thighs pink; pre-cloacal region dark yellow and post post-cloacal region pink; ventral surface of tail pink, with a yellow blotch and blackish speckles at the base (Fig. 8B). All black pigmen- tation on ventral surfaces constitutes a continuous patch, except black pigmentation on tail.
Variation. Scale counts and measurements for Stenocercus nigrobarbatus are presented in Table 1. Loreals 3–7; supralabials 6–8; infralabials 5–8; postrostrals 2–4; second infralabial not in contact third sublabial in all speci- mens; first pair of postmentals in contact in all specimens.
Dorsal coloration in adult males of Stenocercus nigrobarbatus is the same in all adult male paratypes (n = 5) (Fig. 9A). The black coloration on ventral surfaces as a continuous patch is exclusive to adult males (Fig. 9B– C). The juvenile specimen CORBIDI 13718 has a faint black midventral line on the belly (Fig. 9D–E). Another juvenile specimen (CORBIDI 13719) has the gular region and ventral surface of neck covered by a dark gray patch and the midventral region of the belly has scattered dark gray dots (Fig. 9F–G). These immature males (CORBIDI 13718 and 13719) have the pelvic region and the base of tail yellow and the ventral surface of forelimbs cream (Fig. 9D–G). In both specimens the pink coloration on the flanks of the belly is also less intense than in the holotype. In the adult male paratype (CORBIDI 20547) the base of the tail has a black blotch and the pre-cloacal region is yellow with black speckles (Fig. 9C).
Sexual dimorphism: evident in coloration and size (maximum SVL in males 67.0 mm versus 62.0 mm in females). Dorsal coloration in adult females can be gray or brown with irregular dark brown blotches over the ver- tebral line and a light brown dorsolateral stripe from the temporal region to the base of tail (Fig. 9H); dorsal surface of limbs has dark brown or gray transversal bars; sides of head brown or gray with a thin postocular stripe and some scattered dark brown dots; sides of neck yellowish brown with light yellow flecks; jaw and ventrolateral region of neck black or dark gray; body flanks covered by a dark brown reticulation. Ventrally all adult females have the gular region and neck dark gray, belly and limbs are light cream, and the tail is light orange (Fig. 9I).
Juvenile females, between 43.0–51.0 mm of SVL, have the same dorsal and ventral pattern than adult females, only two specimens (CORBIDI 13637 and 13642) have the gular region gray with dark gray speckles, and chest and belly light cream with gray speckles. The smallest juvenile female (CORBIDI 14676) has the gular region covered by gray flecks. The juvenile male CORBIDI 13640 (SVL = 43.0 mm) has the dorsum with dark brown dorsal marks as adult and juvenile females, however, the gular region and chest are gray and the belly is grayish cream. The juve- nile male CORBIDI 15767 (SVL = 53.0 mm) has the same dorsal coloration as adult males but ventrally the gular region and chest are gray, and has a faint gray midventral line on belly flanked by a weak pink hue; pelvic region, ventral surface of hindlimbs and tail are light cream.
|Etymology||The specific epithet “nigrobarbatus” is a noun derived from the Latin words “nigro” (= black) and “barbatus” (= bearded). It refers to the black patch covering the gular region and ventral surface of neck, including the jaw angle, of adult males which resembles a black beard.|