Stenocercus amydrorhytus, Köhler, Gunther & Lehr, Edgar, 2015

Köhler, Gunther & Lehr, Edgar, 2015, Two new species of lizards of the genus Stenocercus (Iguania, Tropiduridae) from central Peru, Zootaxa 3956 (3), pp. 413-427 : 414-420

Stenocercus amydrorhytus sp. nov.

Figs. 1 a, 2–4

Stenocercus cf. ornatissimus: Lehr 2002 : p. 87

Holotype. MUSM 20221, an adult male from Coris, -9.83000, -77.73383, 2785 m, Departamento Ancash, Provincia Aija, Peru, collected 11 February 1997 by Edgar Lehr. Field tag number EL 140.

Paratypes. 6 (all females). All from Coris, Departamento Ancash, Provincia Aija, Peru, collected 11 February 1997 by Edgar Lehr: MUSM 20222, -9.81183, -77.72500, 2900 m. MUSM 20224, -9.82867, -77.73250, 2810 m. SMF 80228, -9.80305, -77.73195, 2890 m. SMF 80229, -9.81112, -77.72750, 3015 m. MUSM 20223, SMF 80230, -9.80305, -77.73112, 3075 m.

Diagnosis. Stenocercus amydrorhytus differs from all other congeners except S. ivitus , S. chrysopygus , S. melanopygus , S. modestus , S. orientalis , and S. stigmosus by the combination of (1) a poorly developed oblique neck fold with a shallow or no mite pocket underneath ( Fig. 1 ); (2) a well developed antehumeral fold with a deep mite pocket underneath; (3) scales on posterior surface of thighs granular; (4) vertebral scales similar in size and shape to adjacent scale rows; (5) three caudal whorls per autotomic segment. Stenocercus amydrorhytus differs from S. ivitus in having lateral nuchals less than half the size of dorsal nuchals (vs. lateral nuchals similar in size to dorsal nuchals in S. ivitus ). Stenocercus amydrorhytus differs from S. orientalis in having predominantly smooth dorsal head scales (vs. prominently keeled dorsal head scales in S. orientalis ). Stenocercus amydrorhytus differs from S. modestus in having 42–47 scales around midbody (vs. fewer than 40 in S. modestus ) and by having a tail length less than 70% of total length (at least 70% in S. modestus ). Stenocercus amydrorhytus differs from S. melanopygus in having a poorly developed oblique neck fold with a shallow or no mite pocket underneath (vs. oblique neck fold absent in S. melanopygus ). Stenocercus amydrorhytus differs from S. stigmosus in having a mostly yellowish venter without blotches or spots in the only known adult male (vs. males with distinct black spots on venter in S. stigmosus ) and in having larger dorsal scales, 44–52, mean 47.3, vertebral scales (vs. dorsal scales smaller, 51–61, mean 56.4, vertebral scales in S. stigmosus ), 42–47, mean 44.3, scales around midbody (vs. 49–57, mean 52.7, in S. stigmosus ). Stenocercus amydrorhytus differs from S. chrysopygus in having larger dorsal scales, 44–52, mean 47.3, vertebral scales (vs. dorsal scales smaller, 54–86, mean 66.0, vertebral scales in S. chrysopygus ), 42–47, mean 44.3, scales around midbody (vs. 48–82, mean 64.3, in S. chrysopygus ), 18–21, mean 19.3, gulars (vs. 23–28, mean 22.5, in S. chrysopygus ), and 23–26, mean 24.4, subdigital lamellae under fourth toe (vs. 22–30, mean 26.0, in S. chrysopygus ).

Definition. (1) Maximum total length in males 68 mm (n = 1); (2) maximum total length in females 60.5 mm (n = 6); (3) vertebrals 44–52; (4) paravertebrals 44–51; (5) scales around midbody 42–47; (6) supraoculars 5–6; (7) internasals 4; (8) postrostrals 4–6; (9) loreals 1–2; (10) gulars 18–21; (11) lamellae on Finger IV 17–19; (12) lamellae on Toe IV 23–26; (13) posthumeral mite pocket present as one or more vertical folds or ridges (Type 1 of Torres-Carvajal 2007); (14) postfemoral mite pocket shallow, with a posteroventrally oriented slit-like opening (Type 2 of Torres-Carvajal 2007); (15) parietal eye present; (16) occipital scales small, smooth, juxtaposed; (17) projecting angulate temporals absent; (18) enlarged supraoculars occupying most of supraocular region in one row absent; (19) scales on frontonasal region smooth, juxtaposed; (20) preauricular fringe present; (21) antegular, antehumeral, gular, longitudinal, postauricular, supra-auricular, and transverse antegular neck folds present, oblique fold ill-defined without deep mite pocket; (22) lateral nuchals smaller than dorsal nuchals; (23) posterior gulars smooth, imbricate, apical pit absent; (24) lateral body scales smaller than dorsal body scales; (25) vertebrals same size as adjacent dorsals, not forming a continuous longitudinal row; (26) dorsolateral crests absent; (27) ventrals smooth, imbricate; (28) scales on posterior surfaces of thighs granular; (29) prefemoral fold absent; (30) inguinal groove absent; (31) preanals not projected; (32) tail not compressed laterally in adult males; (33) tail length 61–67 % of total length; (34) three caudal whorls per autotomic segment; (35) caudals not spinose; (36) dark stripe that extends anterodorsally from subocular region to supraciliaries absent; (37) color pattern of gular region in adult females with dark streaks; (38) color pattern of gular region in adult males with dark streaks forming a reticulum; (39) black blotch on ventral surface of neck in adult males absent; (40) dark midventral stripe in adult males absent; (41) black patches on ventral surface of thighs in adult males absent; (42) background color of dorsum grey or brown.

Description of the holotype. Adult male, as indicated by partly everted hemipenes; SVL 68.0 mm; tail length 140.0 mm (complete); tail more or less round in cross section; axilla to groin distance 30.6 mm; head length 15.6 mm, head length/SVL ratio 0.23; snout length 6.6 mm; head width 11.0 mm; head height 8.7 mm; shank length 14.9 mm, shank length/head length ratio 0.96; scales on parietal and occipital regions small, slightly wrinkled, juxtaposed; parietal eye visible; supraoculars in five rows, smooth, with the lateralmost three rows less than half the size of the medial adjacent row; distinct circumorbitals present; canthals two; anterior-most canthal separated from nasal by a small scale; internasals four; postrostrals four, much wider than long; supralabials six; infralabials seven; loreals two; lorilabials in one row; preocular divided into two scales; lateral temporals keeled, imbricate; gulars in 18 rows between tympanic openings; all gulars cycloid, smooth, imbricate, apical pit absent; second sublabial in contact with the second and third infralabials; first pair of postmentals in contact medially; mental separated from sublabials by the first pair of postmentals; dorsal and lateral scales of neck keeled, imbricate; lateral scales of body smaller than dorsals, but of similar shape, imbricate; scales around midbody 44; vertebrals not differentiated from adjacent scales, in 47 rows, not forming a continuous vertebral row; paravertebrals adjacent to vertebral row equal to vertebrals in size and shape; paravertebrals 46; ventrals smooth, imbricate, smaller than dorsals; preauricular fringe present; antegular, antehumeral, gular, longitudinal, postauricular, supra-auricular, and transverse antegular neck folds present; ventrolateral and prefemoral folds present, oblique fold ill-defined without deep mite pocket; dorsal scales of forelimbs and hind limbs keeled, imbricate; lamellae on Finger IV 19; lamellae on Toe IV 26 (right) and 25 (left); tail rounded; caudals keeled, non-mucronate, imbricate; basal subcaudals smooth, imbricate; posthumeral mite pocket present as one or more vertical folds [Type 1 of Torres-Carvajal (2007)]; postfemoral mite pocket shallow, with a posteroventrally oriented slit-like opening [Type 2 of Torres- Carvajal (2007)].

Coloration in life was recorded as follows ( Fig. 2 ): dorsum dark brown with small greenish-yellow scales scattered along posterior half of body, anterior half with small bluish-gray scales; head dorsally blackish brown with scattered tan scales; ventral surfaces of body (except for anterior half of chest which is pale gray), hindlegs, belly, and base of tale, mustard yellow; throat dark purple brown with pale gray streaks.

Coloration after 17 years of preservation in 70% ethanol was recorded as follows: Dorsal surface of head Raw Umber (280) with Smoky White (261) scales in frontal and parietal regions and a suffusion of Clay Color (20) on snout; dorsal surface of neck Cinnamon-Drab (259) with suffusions of Pale Cyan (157) and True Cinnamon (260); lateral surface of neck Beige (254) with suffusions of Medium Neutral Gray (298); dorsal surface of body Fawn Color (258) with scattered Pale Cyan (157) scales; dorsal surfaces of limbs Sepia (279) with Smoky White (261) Pearl Gray (262) scales; dorsal surface of tail Grayish Horn Color (268) grading into Ground Cinnamon (270) towards tip and with indistinct Smoke Gray (266) bands; ventral surface of head Light Smoke Gray (263) with suffusions of Ground Cinnamon (270) and with Smoky White (261) mottling; ventral surfaces of body Smoke Gray (267) with a Grayish Horn Color (268) central area on venter; ventral surfaces of limbs Grayish Horn Color (268); ventral surface of tail Drab (19) grading into Cream White (57) towards tip.

Variation. The paratypes agree well with the holotype in general appearance, morphometrics and scalation (see Table 1 ).

Etymology. The name amydrorhytus is a compound noun in apposition derived from the Greek words amydros (“indistinct, obscure”) and rythis (“fold, wrinkle”) and refers to the poorly developed oblique neck fold characteristic for this species.

Geographic distribution. Stenocercus amydrorhytus is only known from the vicinity of Coris at elevations of 2785–3075 m asl ( Fig. 8 ).

Natural history notes. The type specimens of Stenocercus amydrorhytus were collected during the morning hours on and under rocks in a grassy area. Sympatric amphibians include Rhinella limensis , and Telmatobius rimac (Lehr 2002, Lehr et al. 2002).

*data taken from Cadle 1998

Figures

FIGURE 1. Lateral view of neck region showing condition of folds and mite pockets in (a) Stenocercus amydrorhytus (MUSM 20222); (b) S. chrysopygus (SMF 80207); (c) S. johaberfellneri (MUSM 20228); (d) S. ornatissimus (MUSM 4974); (e) S. latebrosus (MUSM 17111). Scale bars equal 5.0 mm. Photos by G. K.

FIGURE 2. Stenocercus amydrorhytus in life: (a) dorsal view; (b) ventral view. Photos by E. L.

FIGURE 8. Map indicating collecting localities of selected species of Stenocercus (details see text). Each symbol can represent one or more adjacent localities. Red circle: Stenocercus johaberfellneri; blue triangle: S. amydrorhytus; red triangles: S. chrysopygus; green squares: S. ornatissimus; black circles: S. latebrosus.

Tables

TABLE 1. Selected measurements, proportions and scale characters of the species related to Stenocercus amdrorhytus and S. johaberfellneri. Range is followed by mean value and standard deviation in parentheses. For abbreviations see text.

	S. amydrorhytus S. chrysopygus n = 7 n = 26	S. johaberfellneri n = 11	S. latebrosus * n = 37	S. ornatissimus * n = 21
Maximum SVL males	68 mm 80 mm	57 mm	76 mm	61 mm
Maximum SVL females	64 mm 63 mm	48 mm	67 mm	59 mm
Scales around midbody	42–47 56–72 (44.3±1.60) (63.7±4.85)	46–53 (49.2±2.48)	38–57 (44.2±4.19)	49–60 (52.6±3.03)
Vertebral scales	44–52 59–72 (47.3±2.63) (64.1±3.56)	47–53 (50.0±2.00)	43–53 (48.2±3.07)	52–59 (55.4±2.38)
Gular scales	18–21 23–28 (19.3±1.25) (25.6±1.50)	19–24 (21.7±1.56)	18–26 (20.9±1.79)	19–26 (22.3±1.71)
Internasals	4 2–5 (4.0±0.00) (3.6±0.85)	2–4 (3.8±0.60)	2–4 (3.5±0.60)	2–4 (mode = 4)
Fourth toe subdigitals	23–26 24–31 (24.4±0.85) (28.4±2.10)	23–27 (24.2±1.21)	23–28 (25.2±1.55)	20–29 (24.1±1.85)
Tail length/total length	0.61–0.67 0.64–0.69 (0.65±0.02) (0.66±0.02)	0.62–0.68 (0.67±0.02)	0.63–0.70 (0.67±0.02)	0.64–0.70 (0.67±0.02)