Liolaemus bibronii, Bell, 1843

REDESCRIPTION OF LIOLAEMUS BIBRONII View in CoL

( FIGS 6, 7)

Holotype: British Museum of Natural History No. xxi.81a (renumbered 1946.8.5.68). Female.

Diagnosis: Liolaemus bibronii is a small (Max SVL 53.72 mm) slender species, member of the L. alticolorbibronii group. It is a member of this group, because it exhibits the corresponding character states proposed by Quinteros (2012, 2013). As a member of the L. alticolor – bibronii group, L. bibroni differs in colour pattern from the species of the L. belli group Gray, 1845, L. chillanensis Müller & Hellmich, 1932 , L. elongatus Koslowsky 1896 , L. kriegi Müller & Hellmich, 1939 , L. leopardinus Müller & Hellmich, 1932 , L. monticola Müller & Hellmich, 1932 , L. nigromaculatus ( Wiegmann, 1834) and L. pictus Duméril & Bibron, 1837 groups. Some members of the L. gravenhorsti Gray, 1845 and L. robertmertensi groups show dorsolateral stripes, but those species differ from those of the L. alticolor – bibronii group in the maximum SVL (65 mm in those two groups, and 60 in L. alticolor – bibronii group). The members of the L. alticolor – bibronii group also have well-devolved neck folds, which are absent in some species of the L. robertmertensi and L. gravenhorsti groups.

Liolaemus bibronii is geographically isolated (> 2000 km) from L. alticolor Barbour, 1909 , L. aparicioi Ocampo et al., 2012 , L. bitaeniatus Laurent, 1982 , L. chaltin Lobo & Espinoza, 2004 , L. chavin , L.chungara Quinteros et al., 2014 , L. incaicus Lobo et al., 2007 , L. pachacutec , L. pagaburoi Lobo & Espinoza, 1999 , L. paulinae Donoso Barros, 1961 , L. puna Lobo & Espinoza, 2004 , L. ramirezae Lobo & Espinoza, 1999 , L. tacnae Shreve, 1941 , L. variegatus Laurent, 1984 , L. walkeri , L. wari and L. yanalcu Martinez Oliver & Lobo, 2002 , which are distributed in Bolivia, Peru and northern Argentina and Chile. Despite that, we include comparisons of L. bibronii and these species. A vertebral line in dorsum is evident in L. bibronii , but is absent in L. bitaeniatus and L. incaicus . Males of L. chavin , L. pachacutec , L. wari and L. walkeri exhibit a partial or total ventral melanism, which is absent in L. bibronii . Dorsal scales of body show an evident mucron in L. bibronii , which distinguishes it from L. alticolor , L. chavin , L. pachacutec , L. paulinae and L. tacnae (without mucron). Temporal scales are smooth in L. bibronii , while they are weakly keeled in L. alticolor , L. chaltin , L. chungara , L. incaicus , L. pagaburoi , L. pyriphlogos Quinteros, 2012 , L. ramirezae , L. variegatus and L. yanalcu , and markedly keeled in L. aparicioi , L. bitaeniatus and L. variegatus . Neck scales are laminar and smooth in L. bibronii , a character state that distinguishes it from L. alticolor and L. yanalcu (laminar and weakly keeled), from L. aparicioi , L. bitaeniatus , L. chaltin , L. incaicus , L. pagaburoi , L. paulinae , L. puna , L. pyriphlogos , L. ramirezae and L. variegatus , (laminar and keeled), and from L. chungara (exhibits both granular and laminar scales).

Liolaemus abdalai , L. araucaniensis Müller & Hellmich, 1932 , L. curicencis Müller & Hellmich, 1938 , L. cyaneinotatus , L. exploratorum Cei & Williams, 1984 , L. fuscus , L. gracilis , L. lemniscatus , L. sanjuanensis , L. saxatilis , L. tandiliensis Vega et al., 2008 and L. yalguaraz are distributed in central and southern Argentina and Chile. The presence of a vertebral line in L. bibronii distinguishes this taxon from L. abdalai , L. exploratorum , L. fuscus , L. lemniscatus Gravenhorst, 1838 , L. sanjuanensis and L. saxatilis (which lack a vertebral line). Paravertebral spots are evident in L. bibronii , which distinguishes this taxon from L. fuscus and L. gracilis (paravertebral spots absent). Dorsal scales of body show an evident mucron in L. bibronii , differing from L. tandiliensis (without mucron) and from L. yalguaraz (tiny mucron). Number of scales around midbody are larger in L. bibronii (45–52) than in L. abdalai and L. gracilis (33–44). Also, the numbers of scales of the neck distinguish L. bibronii (30–33) from L. abdalai , L. gracilis , L. lemniscatus , L. saxatilis and L. tandiliensis (20–29) and from L. exploratorum (34–41). The surface of the head is smooth in L. bibronii , being slightly rugose in L. exploratorum , and rugose in L. lemniscatus and L. saxatilis . Temporal scales are smooth in L. bibronii , differing from L. abdalai , L. curicensis , L. exploratorum , L. fuscus , L. tandiliensis and L. yalguaraz (slightly keeled) and from L. cyaneinotatus , L. lemniscatus , L. sanjuanensis , L. saxatilis (keeled). Moreover, neck scales of L. bibronii are smooth, unlike L. abdalai , L. curicensis (some scales are keeled), L. cyaneinotatus , L.fuscus , L.lemniscatus , L.sanjuanensis , L.saxatilis and L. tandiliensis (keeled neck scales). Males of L. bibronii are bigger (53.42–53.72 mm) than males of L. abdalai , L. fuscus , L. lemniscatus and L. saxatilis (max. SVL 52 mm) and smaller than males of L. exploratorum and L. curicencis (min. SVL 54 mm). Females of L. bibronii (45.6–49.8 mm) are larger than females of L. abdalai (max. SVL 40 mm) and L. fuscus (max. SVL 44 mm), and smaller than L. gracilis (min. SVL 52 mm).

Liolaemus bibronii has a set of character states that differs from the three new species described here: L. sp. from Ojos de Agua, L. sp. from Comallo and L. sp. from Malargüe. The contact between nasal and rostral is broad in L. bibronii and narrow in L. sp. from Ojos de Agua. In L. bibronii , the nasal scale is separated from the canthal by one scale, whereas in L. sp. from Ojos de Agua, there are two scales between nasal and canthal. There are five scales between frontal and supercilliaries in L. sp. from Ojos de Agua, while there are four in L. bibronii . In specimens of L. bibronii the fourth supralabial never contacts the subocular scale, whereas in 60% of specimens of L. sp. from Ojos de Agua the fourth supralabial contacts the subocular scale. Colour patterns are similar between L. bibronii and L. sp. from Ojos de Agua, but some differences do exist. Paravertebral spots are line-shaped in L. sp. from Ojos de Agua, while they are rounded in L. bibronii . In the head dorsum of specimens of L. bibronii , there exists a black line surrounding the interparietal scale, which is absent in L. sp. from Ojos de Agua. The ventral surface of the tail is immaculate in L. sp. from Ojos de Agua, while L. bibronii has black to grey spots on the ventral surface of the tail. Table 4 summarizes the main statistical differences between L. bibronii and the three new species described. Lengths of first, second and third toes are smaller in L. bibronii than in L. sp. from Ojos de Agua. On the other hand, the length of the fourth toe in L. bibronii is larger than in L. sp. from Ojos de Agua. Tibia length is larger in L. sp. from Ojos de Agua than in L. bibronii . Number of infradigital lamellae of the second finger is larger in L. sp. from Ojos de Agua than in L. bibronii . The number of infradigital lamellae on first, second, third and fourth toes is smaller in L. bibronii than in L. sp. from Ojos de Agua. There is one scale between nasal and canthal in L. bibronii , while there are two scales in L. sp. from Malargüe. In L. bibronii , there are five scales between frontal and supercilliaries, whereas in L. sp. from Malargüe there are six or seven scales. The number of supercilliaries is larger in L. sp. from Malargüe (Average) than in L. bibronii (5–6). Liolaemus sp. from Malargüe exhibits enlarged scales in the anterior edge of the auditory meatus, whereas in L. bibronii these scales are absent. The number of scales that form the circumorbital semicircle is larger in L. sp. from Malargüe (Average) than in L. bibronii (average) . The subocular scale in L. bibronii is white (lighter than loreal region), having the same colour as the loreal region in L. sp. from Malargüe. Paravertebral spots are rounded in L. bibronii , whereas in L. sp. from Malargüe, these spots are merged forming a longitudinal stripe. In L. bibronii , there exists a black line surrounding the interparietal scale, which projects forward to the frontonasals; his is absent in L. sp. from Malargüe. The subocular scale is white (lighter than the loreal region) in L. bibronii , whereas in L. sp. from Malargüe, the subocular scale shows the same colour as the loreal region. Snout– vent length is larger in L. bibronii than in L. sp. from Malargüe. The length of the fifth finger is smaller in L. bibronii than in L. sp. from Malargüe. The length of the fourth toe is larger in L. sp. from Malargüe than in L. bibronii . The head length is larger in L. sp. from Malargüe than in L. bibronii . The head in L. bibronii is wider than in L. sp. from Malargüe. Tibia length is larger in L. sp. from Malargüe than in L. bibronii . The number of neck and gular scales is larger in L. bibronii than in L. sp. from Malargüe. The number of infradigital lamellae of L. bibronii is lower than in L. sp. from Malargüe. There is one scale between nasal and canthal scale in L. bibronii , whereas in L. sp. from Comallo there are two scales. In L. bibronii , four scales separate frontal from supercilliaries, there being five in L. sp. from Comallo. The absence of enlarged scales in the anterior margin of the auditory meatus distinguishes L. bibronii from L. sp. from Comallo, which exhibits enlarged scales. The number of scales of circumorbital semicircles is lower in L. bibronii than in L. sp. from Comallo (average, respectively). An antegular fold is evident in L. sp. from Comallo, whereas this fold is absent in L. bibronii . The fourth supralabial scale never contacts the subocular scale in L. bibronii , whereas in L. sp. from Comallo, that contact exists in some specimens (90%). In the dorsal region of the head there is a black line surrounding the interparietal scale, which projects forward to frontonasals in L. bibronii , whereas it is absent in L. sp. from Comallo. Paravertebral spots are rounded in L. bibronii , being irregularly shaped in L. sp. from Comallo. The ventral region of the tail exhibits spots in L. bibronii , but is spotless in L. sp. from Comallo. The number of scales around the midbody is larger in L. sp. from Comallo than in L. bibronii . Neck and gular scales are more numerous in L. sp. from Comallo than in L. bibronii . The number of infradigital lamellae on the second finger is lower in L. bibronii than in L. sp from Comallo. The number of infradigital lamellae of the second, third and fourth toes is lower in L. bibronii than in L. sp from Comallo.

Description of the holotype: The following is the original description by Bell (1843) between parentheses are comments made by the authors.

Head moderately short, obtuse, covered with rather large slightly convex scales; a single row of scales between the labial and the orbitar (one row of lorilabials); the anterior margin of the ear has a single tooth (one large scale projecting in the anterior margin of auditory meatus). The temples and the sides of the neck are covered with imbricated scales, which have no carina – those of the neck, especially those on the fold of the skin are smaller and more raised than the others (temporal and neck scales smooth, scales below the antehumeral fold are rounded). The scales of the back are rather large, rhomboidal, with a distinct carina, terminating in a point (dorsals scales rhomboidal, keeled, and mucronated). Those of the abdomen and sides are all of them entire at the margin. The posterior surface of the thighs is wholly granular.

Given that the only specimen collected was a female; the number of pre-anal pores is unknown.

In general, the background colour of this species is brownish grey. They possess a black longitudinal line (vertebral line) which runs down the middle of the back and tail. There are two series of black spots on each side (paravertebral spots), and a small interrupted fascia of the same colour extends from shoulder to thigh (spots in lateral field). The belly is of a uniform dirty white.

Dimensions

Length of the head: 6 lines (15.24 mm); Length of the body: 1 Inch, 6 lines (40.64 mm); Length of the tail: 3 Inches, 4 lines (86.36 mm); Length of the anterior extremity: 7 lines (17.78 mm); Length of the posterior extremity: 1 Inch, 1 line (27.94 mm).

Character states of the holotype measured in this study (adult female ( Fig. 6): Snout–vent length (SVL) 51.84 mm; axilla–groin distance 25.2 mm. Head 12.1 mm long (from anterior border of auditory meatus to tip of snout), 9.5 mm wide (at anterior border of auditory meatus) and 6.7 mm high. Interorbital distance (between postorbital semicircles) 5.1 mm. Eye–nostril distance 1.9 mm. Tibia length 7.2 mm. Foot length 14.9 mm (from ankle to tip of claw on fourth toe). Dorsal head scales smooth between rostral and anterior border of auditory meatus. Seven smooth temporals. Interparietal subpentagonal, smaller than parietal in size, surrounded by seven scales. Frontal azygous. Five scales between frontal and rostrals. Supraorbital semicircles incomplete. Three enlarged supraoculars. Four scales between frontal and supercilliaries. Five flat, elongate, imbricate supercilliaries. Canthal separated from nasal by one scale. Loreal region flat. Seven scales, including rostral, surrounding nasals. Nasals in contact with rostral. Seven lorilabials, third to seventh in contact with subocular. Six enlarged supralabials. Fourth supralabial curved upward posteriorly, not in contact with subocular. Four infralabials, slightly taller than supralabials. Orbit diameter 1.9 mm (measured between upper and lower ciliaries). Subocular scale elongate, length 3.7 mm. Preocular unfragmented. Longitudinal ridge along upper margin of the three ocular scales. Rostral scale three times as wide (1.5 mm) as high (0.5 mm). Mental scale twice as wide (3.01 mm) as high (1.4 mm), followed posteriorly by two rows of four chinshields. Three scales in contact with second infralabial. Scales of throat between chinshields subimbricate. Thirty-four gulars between auditory meatus. Two (one enlarged) outward projecting laminar scales along anterior border of auditory meatus. Auditory meatus higher (1.9 mm) than wide (0.9 mm). Lateral scales of neck smooth and laminar. Antehumeral fold distinct. Thirty-three scales in neck (between posterior margin o auditory meatus and shoulder). Twenty-three scales between auditory meatus and antehumeral fold (counted along postauricular and longitudinal folds). Forty-nine dorsal scales between occiput and anterior surface of thighs. Dorsal body scales lanceolate/rhomboidal, imbricate, keeled and mucronate. Forty-eight scales around midbody. Eighty-six ventrals between mental and the cloaca. Precloacal pores absent.

Colour of holotype in alcohol ( Fig.6): Dorsal background, light brown. With a black, complete vertebral line which extends to tip of tail. Dorsolateral stripes absent. The paravertebral region has the same colour than vertebral region. Two rows of rounded paravertebral spots are distinct (ten between fore and hindlimbs). Lateral field, light brown, with dark brown/black rounded spots. Ventrolateral line absent. Head lighter than dorsum (light brown), with a black line surrounding the interparietal scale and a black line that starts in the anterior margin of the interparietal scale and crosses the frontal scale. Paravertebral spots extend over the head along the supraocular scales. Sides of dorsal region of the head with dark brown spots. Dark brown spots on supra and infralabial scales. Temporal region with two dark brown lines, the upper one beginning in the posterior margin of the eye, and the lower one in the posterior margin of subocular scale; both finishing in the anterior margin of the auricular meatus. Some dark brown spots are evident on the neck. Fore and hindlimbs light brown with dark brown spots. Ventrally, throat, chest and belly light brown, spotless. Region of chinshields lighter than central region of throat. Fore and hindlimbs, immaculate light brown, almost white. Tail, dorsally light brown with black vertebral line. Ventrally light brown, spotless. Lateral region of tail with dark brown spots (which are as a continuation of those from the lateral field of body).

Variation: Based on six topotypes. Snout–vent length 53.42–53.72 mm (mean = 53.50; SD = 0.21) in males; 45.56–49.82 mm (mean = 47.70; SD = 2.90) in females. Head length 11.07–12.10 mm (mean = 11.60; SD = 0.50) in males; 9.54–11.70 mm (mean = 10.62; SD = 1.50) in females. Head width 8.42–9.75 mm (mean = 9.22; SD = 0.07) in males; 7.43–8.88 mm (mean = 8.25; SD = 0.70) in females. Head height 6.38–7.15 mm (mean = 6.70; SD = 0.39) in males; 4.83–6.42 mm (mean = 5.88; SD = 0.91) ion females. Axilla–groin distance 23.70– 27.29 mm (mean = 25.50; SD = 2.50) in males; 20.09–27.30 mm (mean = 23.53; SD = 3.51) in females. Tail length 87.76 mm (only one specimen a non-autotomized tail). Tibia length 6.67–7.63 mm (mean = 7.21; SD = 0.40). Foot length (from ankle to the tip of fourth claw) 15.40–16.58 mm (mean = 15.99; SD = 0.80) in males; 14.01–15.42 mm (mean = 14.71; SD = 0.99) in females. Midbody scales 45–52 (mean = 48.66; SD = 3.01). Dorsal scales, 45–54 (mean = 50.5; SD = 3.4) between occiput and anterior surface of thighs. Dorsal head scales (Hellmich’s Index) 10–12 (mean = 11; SD = 0.7). Ventrals 75.0–89.0 (mean = 82.2; SD = 5.6). Scales around interparietal 6.0–8.0 (mean = 6.7; SD = 1.03). Three enlarged supraoculars. Preocular not divided, not fused to subocular. Subocular scale length 3.34–4.20 (mean = 3.70; SD = 0.30). Temporals 7–8 (mean = 7.4; SD = 0.5), smooth. Scales of neck smooth and laminar. Number of scales on neck (between auditory meatus and shoulder, along the horizontal fold) 30–33 (mean = 31.6; SD = 1.03). Scale between auditory meatus and antehumeral fold 19–24 (mean = 21.5; SD = 1.9). Gulars 33–37 (mean = 35; SD = 1.6). Supralabials 6–8 (mean = 6.3; SD = 0.8). Infralabials 4–5 (mean = 4.3; SD = 0.5). Fourth supralabial upturned, never in contact with subocular scale. Seven scales around nasals. Five scales between rostral and frontal. Two postrostrals, with 5–7 scale organs each (mean = 5.1; SD = 1.2). Six to seven lorilabials (mean = 6.2; SD = 0.4), three to four in contact with subocular. Subdigital lamellae on fourth finger 16–18 (mean = 17.2; SD = 0.9); on fourth toe 21–23 (mean = 21.8; SD = 0.8). Three precloacal pores in males, absent in females .

Colour in life ( Fig. 7): Dorsal background brown. Black, complete vertebral line, which extends to tip of tail. Dorsolateral stripes faded or absent; when present, they begin at the upper margin of the eye and extend to the forelimbs. The paravertebral region presents the same colour as the vertebral region. Two rows of rounded and black paravertebral spots are distinct. In some males, some white bright spots are speckled in dorsum and lateral fields. Lateral field, brown or dark brown, with dark brown/black spots. These spots can form a vertical bar, reaching the ventrolateral line and the dorsolateral stripes. In some males, lateral field shows rounded, white bright spots. Ventrolateral line absent in some specimens, but evident and incomplete in others. Head lighter than dorsum (light brown), with a black line surrounding the interparietal scale, and a black line that is born in the anterior margin of the interparietal scale and crosses the frontal scale. Paravertebral spots extend over the head along the supraocular scales. Sides of dorsal region of the head with dark brown spots, with dark brown spots on frontonasal scales. Temporal region with two white lines: the upper begins in the posterior margin of the eye and joins the dorsolateral stripes; the lower begins at the posterior margin of subocular scale and finishes at the anterior margin of the auricular meatus. Subocular white (lighter than loreal region). Fore and hindlimbs the same colour as the dorsum, with light brown spots. Ventrally, throat, chest and belly grey, spotless in most of the specimens. Some specimens can show a few line-shaped spots in the lateral region of the throat. Tail dorsally brown with black vertebral line and two rows of paravertebral spots. Ventrally light brown, speckled with dark grey/black spots. Lateral region of tail with dark brown spots (which are a continuation of those from the lateral field of body).

Distribution ( Fig. 8): Before this contribution, the distribution of Liolaemus bibronii was wide, occupying many localities in southern to central Argentina and localities in Chile. Since this contribution, Liolaemus bibronii is known only from the type locality in Puerto Deseado and nearby localities, such as Tres Cerros and Las Heras, all from Santa Cruz Province, Argentina.

Biology: Liolaemus bibronii inhabits a region characterized by mixed steppe composed of grasses and low, thorny shrubs. Vegetation is dominated by Chuquiraga avellanedae Lorentz , Nassauvia glomerulosa D. Don ( Asteraceae ) and Junellia tridens (Lag.) Moldenke ( Verbenaceae ) and by grasses of the genus Stipa spp. ( Poaceae ). The climate is cold, dry and windy with frequent winter frosts and a mean summer temperature of 17 °C. Annual rainfall ranges between 100 and 300 mm, and concentrates during autumn and winter; snowfall is rare. This species inhabits in sympatry with Diplolaemus bibronii Bell, 1843 , Homonota darwinii Boulenger, 1885 , Liolaemus boulengeri Koslowsky, 1898 , L. fitzingerii ( Duméril & Bibrón, 1837) , L. gracilis , L. kingii ( Bell, 1843) and L. lineomaculatus, Boulenger, 1885 .