Potamites erythrocularis, Chávez, Germán & Catenazzi, Alessandro, 2014

Chávez, Germán & Catenazzi, Alessandro, 2014, A new Andean lizard of the genus Potamites (Sauria, Gymnophthalmidae) from Manu National Park, southeastern Peru, Zootaxa 3774 (1), pp. 45-56 : 46-52

Potamites erythrocularis new species

Holoytype (Figures 1, 2): MUSM 28056, an adult male from Peru, Cusco Region, Province of Paucartambo, District of Kosñipata, Suecia, S13.106270, W71.570640, 1950 m above sea level, collected on 4 February 2009 by A. Catenazzi, J. C. Jahuanchi, A. Machaca, C. Quispe, E. Luna and R. Sotelo.

FIGURE G 1. Dorsolateral (A) d(A) and l ventral i (view) f (B l) of i coloration i lif in f life h h of l the holotype l, male S MUSM 28056.

Paratypes ( Figure 3 A–D). Five males: MUSM 28057 collected on 4 February 2009, MUSM 26309, CORBIDI 11484, 11485 collected on 28 June 2012 by A. Catenazzi from the type locality ( Figure 4 ), and MUSM 28058 from the District of Kosñipata, Quebrada San Pedro (S13.058310, W71.549620), 1380 m, collected on 28 January 2009 by A. Catenazzi. Nine females, all from the District of Kosñipata: MUSM 17243–45, MUSM 17247–48 and MUSM 17250 from Bosque de Nubes (S13.07035 W71.56849), 1700 m, collected on 9–11 September 1991 by R. P. Reynolds, A. W. Salas, R. W. Bouchard; MUSM 17265 from San Pedro at km. 155 of Paucartambo–Pilcopata road, 1520 m, collected on 15 September 1991 by R. P. Reynolds, A. W. Salas, R. W. Bouchard; MUSM 28059 from between San Pedro and Santa Isabel, 1320 m, collected on 29 January 2009 by A. Catenazzi; MUSM 17272 from Santa Isabel at km. 157 of Paucartambo–Pilcopata road, 1300 m, collected on 24 September 1991 by R. P. Reynolds, A. W. Salas, R. W. Bouchard.

Diagnosis. Assigned to Potamites by having a tongue with imbricate scale-like papillae, movable eyelids, external ear and heterogeneous dorsal scalation ( Doan & Castoe 2005). (1) Head acuminate from dorsal view, rounded from lateral view, scales on the dorsal surface of the head smooth; (2) frontonasal undivided, usually equal or slightly shorter than frontal, azygous scale absent; (3) prefrontals present; (4) frontal present; (5) nasoloreal suture present; (6) supraoculars four, anteriormost not fused with first superciliary, all supraoculars separated from superciliaries; (7) superciliary series complete, usually four; exceptionally five (8) supralabial-subocular fusion absent; (9) postoculars three; (10) postparietals three; (11) hemipenis in two pairs, transverse sutures perpendicular with respect to midline of body; (12) dorsal scales rectangular, juxtaposed, granular and keeled; (13) 42–45 enlarged transverse dorsal rows at midbody; (14) 30–33 longitudinal rows of dorsal keeled scales; (15) 22 – 24 longitudinal ventral rows; (16) 40–42 femoral pores in males, absent in females; two scales between femoral pores; (17) 9–14 subdigital scales on 4th finger, and 20–24 on 4th toe; (18) forelimb reaching anteriorly the fourth supralabial; (19) tail slightly compressed with two rows of lateral scales per two ventral caudal scales; (20) hemipenis acapitate; flounces lacking calcified spines and forming two chevrons on distal half of hemipenis while its basal half is covered with 4 transverse flounces; some asulcate flounces separated by a small expansion pleat; sulcate flounces about as wide as asulcate flounces; sulcus spermaticus single, flanked by a broad naked expansion pleat widened distally; (21) dorsum dark brown; lateral ocelli present, in two or three pairs in males, usually absent in females; ventral color pattern in males red bright on lower extremities and belly, creamy to pale blue on chest, and blue with red sprinkles and dark blotches on throat and head; ventral coloration in females yellow to pale brown on limbs, chest and tail, orange on the belly, and creamy white on throat and head; (22) lower palpebral disc transparent, undivided, oval.

Potamites erythrocularis is distinguished from other Potamites and Neusticurus species except for P. montanicola by having keeled scales that are scattered, and by females lacking femoral pores, and except for P. strangulatus , by males having a red ring around the eyes. The new species is differentiated from P. montanicola by bearing an undivided frontonasal (divided in P. montanicola ), having a maximum SVL of 83.6 mm in males (maximum SVL in males of P. montanicola 68.6 mm) and showing flat temporal scales (slightly tuberculate temporal scales in P. montanicola ). Superficially, P. erythrocularis resembles P. ecpleopus and P. ocellatus , however it differs from P. ecpleopus (characters for P. ecpleopus in parenthesis) by having a lower number of keeled scales on dorsum (see specimens reviewed Appendix 1): 30–33 (36–45), frontonasal undivided (divided), frenocular scale pentagonal (triangular) and a lower number of femoral pores bearing 19–21 in males and lacking in females (25–48 in males and 1–15 in females). Furthermore, the new species differs from P. ocellatus (characters for P. ocellatus in parenthesis) by its bigger size: 83.6 mm as maximum SVL in males (75 mm), dorsal scales highly keeled (dorsal scales slightly keeled), temporal region covered by medium size polygonal flat scales (vs. covered by large scales interspersed with granules) and has a lower number of femoral pores in males: 20–21 (vs. 41).

Potamites erythrocularis is distinguishable from other Potamites species by its size, with a maximum SVL of 83.6 mm in males, is longer than P. cochranae (70 mm) P. juruazensis (50 mm) and P. ocellatus (75 mm). Furthermore, the new species has an undivided transparent oval in the lower eyelid (divided in P. cochranae ), bears dorsal crests (absent in P. strangulatus ), has tubercles on flanks (absent in P. cochranae and P. strangulatus ), possesses a superficial tympanum (shallow in P. cochranae ), females lack femoral pores (femoral pores present in females of all species of Potamites excepting some individuals of P. juruazensis and females of P. montanicola ), and males have 40–42 femoral pores (vs 26–30 in P. apodemus , 10–16 in P. juruazensis and 45–59 in P. strangulatus ).

Furthermore, the new species can be distinguished from species of the genus Neusticurus by bearing an undivided palpebral disc (divided in N. bicarinatus , N. racenisi , N. rudis , N. tatei ), a dorsal crest (absent in N. racenisi , N.rudis ), tubercles on flanks (absent in N.medemi , N.racenisi , N.tatei ), by having a slightly recessed tympanum (deep in N.bicarinatus , N.medemi , N.racenisi and shallow in N.rudis ), by females lacking femoral pores (present in females of all species of Neusticurus ), by males having 40–42 femoral pores (vs 40–62 in N. bicarinatus , 58–64 in N. medemi , 62–72 in N. racenisi , 32–46 in N. rudis , 60–61 in N. tatei ), and by its intermediate size. Males of the new species have a maximum SVL of 83.6 mm, which is longer than N.apodemus (47 mm) and N.tatei (72 mm), but smaller than N.bicarinatus (117 mm), N. medemi (121mm), N. racenisi (104 mm) and N. rudis (94 mm).

Description of the holotype. Adult male MUSM 28056, body long, laterally compressed, SVL 83.65 mm; tail (complete) length 141.0 mm, axilla to groin distance 38.1 mm; head length 23.01 mm; head width 15.48 mm; shank length 13.81 mm. Pupil round. Tympanum slightly recessed, overhung by surrounding scales of surface of head. Head scales smooth and flat; rostral scale wider (3.25 mm) than long (1.76 mm), higher than adjacent supralabials, in contact with frontonasal, nasoloreal, and first supralabials posteriorly; frontonasal undivided, pentagonal, slightly longer (3.58 mm) than wider (2.81 mm), widest posteriorly, in contact with nasoloreal and frenocular laterally, prefrontals posteriorly; nasoloreal almost triangular, apex in contact with rostral, nasoloreal suture present; prefrontals in contact medially, contacting first superciliary, first supraocular, frontal; frontal longer (4.42 mm) than wider (3.03 mm), anterior suture angular with point directed anteriorly, lateral sutures straight to slightly concave, posterior suture angular with point slightly directed posteriorly, in contact with first, second and third supraocular laterally, frontoparietals posteriorly; frontoparietals paired, pentagonal, in contact with third and fourth supraocular, parietals and interparietal posteriorly; supraoculars four, none in contact with ciliaries; superciliary series complete, four superciliaries, anteriormost superciliary rectangular, longer (2.20 mm) than wider (1.23 mm), not fused with anteriormost supraocular, in contact with frenocular anteriorly, prefrontal, first supraocular, second supraocular and first to third ciliar laterally and with second superciliar posteriorly; interparietal subhexagonal, longer (4.92 mm) than wider (3.50 mm), in contact with parietals laterally, postparietals posteriorly; parietals pentagonal, in contact with fourth supraocular anterolaterally, temporal scales laterally, dorsalmost postocular, postparietals posteriorly; postparietals nine, smaller than interparietal, asymmetrical, bordering parietals and interparietal; palpebral disc oval, undivided, unpigmented; frenocular squarish, in contact with nasoloreal anteriorly; postoculars three; temporals ovoid to polygonal, vary in size, juxtaposed, smooth; supralabials four; infralabials five; mental symmetrical, wider (3.30 mm) than long (2.26 mm), in contact with first infralabials, postmental posteriorly; postmental single, pentagonal, its posterior suture angular, point directed posteriorly, in contact with first and second infralabials; genials in two pairs, anterior pair subquadrangular, in contact at midline and with postmental anteriorly, second and third infralabials laterally, and second pair of genials posteriorly; posterior genials pentagonal, in contact with third and fourth infralabials laterally; scale rows between genials and collar fold (along midventral line) 19, subimbricate, posteriormost row bearing cuadrangular scales, other rows bearing rounded scales; posteriormost gular row enfolded posteriorly, concealing two granular scale rows; lateral neck scales conical of a medium size (14–15 mm), also very small smooth scales (0.3 mm), sub imbricate; dorsal neck has 8 rows of tubercles that become 2 rows of dorsal keeled scales (the other rows become irregular or combine to join the 2 rows). Scales on trunk heterogeneous, granular laterally, scattered conical tubercles on both flanks of body are posteriorly projected; four longitudinal rows of dorsal keeled scales from the post occipital region to anterior level of insertion of the forelimbs, distributed irregularly (scattered) on dorsum and becoming four regular rows again at the posterior level of insertion of hind limbs, separated by granular scales; transverse dorsal count (enlarged rows at midbody) at fifth transverse ventral scale row 41, at 10th transverse ventral scale row 36, at 15th transverse ventral scale row 36; lateral scales on body near insertion of forelimb small, conical dorsally, mostly granular; ventrals squarish and juxtaposed; complete longitudinal ventral count 24; longitudinal ventral scale rows at midbody 8; 44 scales around midbody; anterior preanal plate scales two; posterior preanal plate scales three; tail complete, compressed, dorsal and dorsolateral surface of tail with at least 77 whorls of enlarged keeled scales foarming two crests running longitudinally along the tail, rows of crests separated by 3–5 small, irregularly shaped smooth scales, midventral subcaudals squarish, smooth, cloacal plate smooth, comprising two rounded, triangular, anterior scales, and three posterior scales. Middle posterior scale smaller, shaped like elongated trapezoid, outer posterior scales shaped like sounded squares. Limbs pentadactyl; digits clawed; forelimb reaching anteriorly to fifth infralabial; anterolateral and dorsal brachial scales keeled, imbricate; midbrachial anterodorsal scale at least twice as large as adjacent scales, slightly keeled; anteroventral, ventral, and posteroventral scales granular, imbricate, conical; antebrachial scales polygonal, keeled; medial antebrachial scales small, polygonal, smooth; dorsal manus scales polygonal, imbricate, smooth; palmar scales small, polygonal, smooth; finger length formula IV> III> II> V> I; dorsal scales on fingers smooth, quadrangular, covering dorsal half of digit, overhanging supradigital scales, 4/4 on I, 8/8 on II, 11/10 on III, 12/12 on IV, 7/8 on V. Subdigital lamellae 5/5 on I, 10/9 on II, 14/14 on III, 15/17 on IV, 10/10 on V; dorsal thigh scales granular, some scales bearing conical tubercles, anterodorsal thigh scales polygonal, largest than adjacent scales, slightly keeled; posterodorsal thigh scales small, granular, dorsalmost scales tuberculate, arranged irregularly, ventral thigh scales rounded, smooth, several times smaller than anterodorsal thigh scales; anterior and anteromedial shank scales granular, juxtaposed, some scales bearing conical tubercles, anteriormost scales of the same size as lateral, posterolateral, and posteromedial shank scales; lateral, posterolateral, and posteromedial shank scales granular, juxtaposed, some scales conicals; toe length formula IV> III> V> II> I; scales on dorsal surface of digits single, quadrangular, smooth, overhanging supradigital scales, four on I, seven on II, twelve on III, 17/18 on IV, eleven on V; subdigital scales single or double, seven on I, 11/12 on II, 16/17 on III, 24/23 on IV, fourteen on V; femoral pores 21–21.

The everted hemipenis is an acapitate organ without a medial welt; apex with two large protrusions separated by the distal end of the sulcus spermaticus; sulcus spermaticus single, flounces lacking calcified spines and forming two chevrons on distal half of hemipenis; sulcate flounces about as wide as asulcate flounces; asulcate flounces becoming shorter distally, four in the basal half and twelve in each protrusion, distal chevrons separated by a small expansion pleat; sulcus spermaticus single, flanked by a broad naked expansion pleat widened distally.

Coloration of holotype in preservative ( Fig. 2 ): Dorsal surface of head, dorsal surface of body, tail, limbs, hands and feet dark brown; orbital region rounded by a creamy yellow ring covering pre-ocular, sub-ocular and post-ocular scales, not covering row of superciliaries and supraocular scales, one pair of lateral ocelli with a bluish white rounded center above insertion of forelimbs; supralabial region with creamy white blotches from first to third supralabial, infralabials and throat dark brown, bearing bluish blotches; flanks bearing three pairs of bluish white blotches, located posteriorly from the pair of ocelli; chest bluish-yellow with some irregular yellow blotches, venter creamy-white with scattered gray blotches. Ventral surfaces of forelimbs dark brown with irregular and diffuse cream blotch; ventral surfaces of thighs pale brown with creamy yellow blotches anterior to femoral pores; ventral surfaces of hands and feet pale brown, turning darker towards tips of fingers; ventral surface of tail creamyyellow at the base becoming dark brown at the end.

Coloration of holotype in life (Fig. 1). The overall coloration of the body is dark brown dorsally and red ventrally. The throat and ventral surface of the head is blue. The subocular and postocular scales are bright orange. There are six lateral ocelli (black ring with white/pale blue center) and four weakly defined ocelli closer to the ventral side. Supralabials and infralabials white with black striations between scales. Gulars gray-blue, white between scales. Mental scale white with black spots, postmental and genials pale blue with black patches. The first 7 rows of transverse rows of ventral scales are predominantly gray-blue, with patches of red. Rows 8–11 are mostly pale pink, with patches of blue-gray. The other rows of ventrals are red, becoming darker posteriorly. The dorsal scales on head, trunk, forelimb and hind limb are dark brown. Lateral anterior edge of forelimbs brown with thin layer of pale blue. Interior brachials pale red, antebrachials pale blue to dark gray. Palmar and digital scales dark gray with pale red between scales. Anterior inner thigh pale red, posterior inner thigh brown with patches of red and pale blue. Ventral crus scales dark brown mottled with white and red. Ventral pes and digital scales dark gray with light red between scales. Dorsal caudal scales and cloacal plate dark brown with light brown spots in regular longitudinal rows. Anterior subcaudal scales pink with gray patches, become gray-blue posteriorly.

Variation. In the type series, only one female (MUSM 17245) is bearing a dorsal crests row with 30 scales, the rest of specimens have 31–33 scales along the dorsal crest. The superciliaries are usually four, but male MUSM 28057 and females MUSM 17245, 17247 and 17272 have 5 superciliary scales. Sexual dimorphism is important: in addition to lacking the red ocular ring, blue throat and red ventral coloration, females lack femoral pores; males are larger (65.9–83.6 mm SVL) than females (64.1–70.9 mm SVL), and head is wider in males (10.9–15.5 mm HW) than in females (9.0– 10.6 mm HW). See Table 1 for variation in selected morphometric and squamation characters in the specimens examined.

Potamites erythrocularis (n=15)

SVL (mm) males 84.30–83.65 (74.75 ± 8.02) females 61.07–70.86 (66.84 ± 3.17) Head lenght/Head width males 1.46–1.78 (1.54 ± 0.11) females 1.62–1.82 (1.72 ± 0.06)

Number of femoral pores males 20–21 (20.33 ± 0.51) females 0 (0.00 ± 0.00)

Scales between tympanum 24–29 (25.73 ± 1.28) Number of supralabials 5–6 (5.06 ± 0.24)

Number of Infralabials 4–5 (4.06 ± 0.24)

Number of supraoculars 4 (0.00 ± 0.00)

Number of superciliars 4–5 (4.16 ± 0.40)

Number of scales around midbody 42–45 (43.33 ± 1.17) Longitudinal dorsal count 30–33 (31.66 ± 0.89) Number of longitudinal ventral scales rows 22–24 (23.4 ± 0.63) Lamellae under 4th toe 20–24 (21.8 ± 1.16) Distribution and ecology. The new species has been found in streams between 1000–2100 m ( Figure 5 ). These streams drain submontane and montane or cloud forests that grow on the steep slopes of the eastern side of the Cordillera de Paucartambo. The species has been found in a variety of lotic habitats, from small and fully shaded seeps, to large streams receiving abundant sunshine throughout the day. During the wet season (November to April), lizards can be seen active in water during the day and night, whereas during the dry (and colder) season (May to October), lizards do not seem to be active at night. Most lizards however were found by lifting rocks in the stream channel or by removing aquatic vegetation. Lizards seen at night were hunting aquatic invertebrates.

Our field observations suggest that these lizards operate at body temperatures significantly lower than those recorded in other gymnophtalmids ( Pianka & Vitt 2003; Vitt et al. 1998a; Vitt et al. 1998b), including montane forest species ( Anaya-Rojas et al. 2010). For example, on 28 June 2012, males CORBIDI 11485 and 11484 were active at 16:50 with a body temperature (T b) of 15.8C and 15.6C respectively. A juvenile found at 21:00 under a rock in the stream had T b = 15.6C. Temperatures are higher, but still relatively cold for a lizard, during the day: four individuals found on 25 October 2012, at the end of the dry season, had T b between 19.7–20.3C in the late morning and early afternoon, when the water temperature ranged between 15.8–17.2C and the air temperature between 20.3–21.6C.

Etymology. The name refers to the red ring surrounding eyes in males.

Species Median Azygous Scale Frontonasal Midbody Tail Compression

Division Scales

P. erythrocularis Absent Absent 43.3 (42–45) Slight

Figures

FIGURE 2. Later, dorsal and ventral view of coloration in life of the head and details of squamation characteristics of the holotype, male MUSM 28056.

FIGURE 3. Dorsolateral and ventral views of male MUSM 28057, SVL 78.5 mm (A, B), female MUSM 28059, SVL 69.5 mm (C, D) and juvenile MUSM 28055, SVL 53.0 mm (E, F), all from the type locality.

FIGURE 4. Map illustrating the type localities of Potamites erythrocularis and P. monticola in the cloud forests of southeastern Peru near Manu National Park.

FIGURE 5. Elevational distribution of 88 specimens of Potamites erythrocularis (including the holotype and paratypes, observations from uncollected specimens, and specimens collected at the type locality and deposited at KU and the USNM).