Liolaemus riodamas, Esquerré, Damien, Núñez, Herman & Scolaro, José Alejandro, 2013

Esquerré, Damien, Núñez, Herman & Scolaro, José Alejandro, 2013, Liolaemus carlosgarini and Liolaemus riodamas (Squamata: Liolaemidae), two new species of lizards lacking precloacal pores, from Andean areas of central Chile, Zootaxa 3619 (4), pp. 428-452 : 439-448

Liolaemus riodamas sp. nov.

Figures 6 to 10

Holotype. MNHNCL-4684, male. Collected by Damien Esquerré and Herman Núñez at Las Damas River, Termas del Flaco, Libertador Bernardo O’Higgins Region; S 34°56' 714-887´´ W 70°23´634-682´´ 2012-2057 masl, between February 1 and 2, 2011.

Paratypes. MNHNCL- 1962 to 1966 and MNHNCL-4682, 4683, 4685 and 4686. MNHNCL-1962, 4682 and 4686 are males and MNHNCL-1963, 1964, 1965, 1966 and 4685 are females. MNHNCL 4682-4686 same data as holotype. MNHNCL- 1962-1966 same locality, collected by Herman Núñez and Antonieta Labra, February 24, 1985. MNHNCL-1964 and 4683 were used for diaphanisation.

Etymology. The name comes from the locality they were found: Las Damas River (In Spanish known as “Río Las Damas”). The common names “Las Damas River Lizard” in English and “Lagarto del Rio Las Damas” in Spanish are proposed.

Diagnosis. Medium to large-sized lizard, with a mean SVL of 80.9 mm and a maximum of 85.5 mm. Sturdy aspect, robust limbs and a strongly folded neck. Tail about 1.5 times the length of the body. 83–96 scales around midbody. General background coloration brown to dark gray, with no defined pattern. Dorsal coloration of the head dark brown to black. Some specimens have individual yellow scales scattered on the posterior region of the dorsum. A light-yellow coloration is observed at the ventral region of some live specimens that extends to the sides of the tail. This species presents the characteristic dorsal squamation pattern of the kriegi group, with small rounded and juxtaposed scales, and tiny granular scales in the interstitial region. The dorsal scales are weakly keeled and only around the vertebral line. It completely lacks precloacal pores, which makes it distinct from almost all of the species of the elongatus-kriegi complex. It is important, therefore, to differentiate this species from all of the species lacking these glands. First, because of this trait, is can be said that this species is not L. ceii as was previously suggested (Núñez & Torres-Mura 1992). Furthermore L. ceii has 102–115 scales around midbody, in contrast with the 83–96 scales in L. riodamas . From the original description of L. thermarum (Videla & Cei 1996) , where it is described lacking precloacal pores, it differs in that L. thermarum would exhibit a dark bilateral stripe on the flanks, absent in the uniform pattern of L. riodamas . According to Avila et al. (2010), L. thermarum has two to three precloacal pores and a dorsal stripe, both traits absent in L. riodamas , however in a recent article (Avila et al. 2012) that sample of lizards is assigned to L. smaug . L. riodamas differs from L. neuquensis and L. coeruleus because these species have a lower number of scales around midbody (68–74 and 63–69 respectively, after Videla & Cei (1996) and Scolaro et al. (2007)), presence of dorsal pattern and a blue/greenish ventral coloration. From L. cristiani it differs because this species has a black stripe along the sides of the trunk, and a smaller body size much smaller, body size (mean SVL of 70.7 vs. 80.9 mm in L. riodamas ). The species differs from L. flavipiceus because the latter has a lower number of scales around midbody (73–81). In addition L. riodamas lacks the body melanism of L. flavipiceus , and the red ventral coloration in some specimens of L. flavipiceus . From L. punmahuida it differs because this species is larger (maximum SVL of 95 mm in L. punmahuida vs. 85 mm in L. riodamas ); furthermore L. punmahuida has an ochre background coloration, and bright red-yellowish coloration in the cloacal region, in contrast to the brown to gray dorsal coloration, and the occasional and slight yellow pigmentation in the cloacal region of L. riodamas . L. riodamas differs from L. tregenzai because this species has a green-bluish ventral coloration, and an evident sexual dichromatism, both traits not observed in L. riodamas . Some L. leopardinus males lack precloacal pores, but this species is clearly distinct from L. riodamas because of the leopard-like dorsal pattern of L. leopardinus . L. capillitas males also lack precloacal pores sometimes, but this species has only 58–67 scales around midbody, and a red cloacal coloration in females, not observed in L. riodamas .

Description of the holotype. Male, with an SVL of 81.83 mm. Head slightly longer than wide: 17.4 mm long (from the anterior edge of the ear opening to the point of the snout), 15.75 mm wide (between the anterior edges of the ear openings) and 10.78 mm high (at the level of the anterior edge of the ear openings). Snout length (from the anterior margin of the eye to the rostral scale): 6.21 mm. Neck wider than head, effect of a prominent longitudinal fold on the neck. Hind limb extended forward barely reaches the armpit. The tail is regenerated. It lacks precloacal pores.

Rostral scale rectangular, 3.2 times wider than high and in contact with eight scales, including the nasals, which touch the rostral with only the anterior corner of the scale. Nasals polygonal, the nostril located posteriorly, occupying half of the scale’s surface. Two postrostrals irregularly squared, followed by four internasal scales, the two medial ones about two times larger than the other two. Three frontal azygos, the most anterior the largest, and the most posterior the smallest. Eight frontonasals in contact with the frontal azygos. Two squared prefrontal scales, the frontal undivided. Two longitudinally elongated postfrontals, the left one transversally divided in half. Interpatietal irregularly pentagonal, in contact with six scales. A gray pineal eye in the middle of interparietal scale. Four small and squared parietal scales, slightly larger than the interparietal, although they resemble two longitudinally elongated parietal scales transversally divided in half. The scales in the nuchal and supratemporal regions are medium-sized, polymorphic, juxtaposed and smooth. 4-5 large supraoculars, accompanied by 22-20 small supraoculars. 8-8 very elongated and imbricate superciliary scales, excluding the canthal. Numerous scale organs on all the dorsal region of the head, increasing in numbers towards anterior part of the head. Canthal scales sharpened towards the anterior end. 6-6 loreal scales, excluding the canthal. A large and elongated subocular scale, divided at the posterior end, forming a small scale, and both together spanning the entire length of the eye. 8-8 lorilabial scales, in one row. 7-8 supralabials, the fourth-fifth one more elongated and curved upwards posteriorly. It has a slightly elongated snout, with the loreal distance (distance between the anterior margin of the eye and the rostral scale) barely larger than the ocular diameter. The scales in the anterior border of the eye are elongated and overlapping, each one with a scale organ on it. 15-15 upper and 14-14 lower palpebrals, all squared and each one with a scale organ on it. Temporal scales rounded, smooth and juxtaposed. Auricular scale barely distinguishable. Timpanic scales poorly developed, small and convex. Scale organs present in all the lateral region of the head, being especially numerous in the lorilabial and loreal scales. Mental scale barely wider than rostral, although twice its height, and in contact with four scales. Four pairs of postmentals, the second pair separated by two scales. 5-5 infralabials, with scale organs scattered on them. Scales in the gular region rounded, smooth and imbricate. Lateral region of neck with a pronounced longitudinal fold, ending with an antehumeral fold. Neck scales small, convex, granular and with very small granular scales in the interstitial space.

Dorsal scales small, smaller than the ventral scales, rounded and juxtaposed. Poorly developed keels on the mid-dorsal scales, and disappearing to the sides. The scales on the flanks therefore are smooth, but in form and arrangement very similar to the dorsal scales, being only slightly larger. Tiny granular scales are scattered in interstitial space in the dorsal region and flanks. No folds are observed in the lateral region of the trunk. Ventral scales are rounded, smooth and imbricate. 85 scales around midbody. Dorsal scales of the arm are subtriangular, smooth and imbricate. Dorsal scales of forearm are very similar but more rounded, as they are in the dorsal region of the hand. On the ventral region of the arm the scales are small, granular, juxtaposed, and surrounded by even smaller granular scales in the interstitial space. The scales on the ventral region of the forearm are as large as the dorsal ones, subtriangular, imbricate, and start showing keels towards the palm, where the scales are completely keeled, triangular, imbricate and with a slightly jagged edge. The third finger of the left hand has 16 rectangular and transversally disposed lamellae, each one provided with three keels. The scales in the dorsal femoral region are rounded, smooth, subimbricate and with few small granular scales on the interstitial region. In the dorsal tibial region they are subtriangular, juxtaposed, slightly keeled and with visible tiny granular scales in the intertstitial region. In the dorsal region of the foot the scales are rounded, smooth and imbricate. The scales on the ventral femoral and tibial regions are rounded, smooth and imbricate. In the plantar region scales are triangular, slightly keeled and imbricate. Some scales in the plantar region are slightly jagged on the edges. The fourth toe has 25 rectangular and transversally disposed lamellae, each one provided with three keels. The dorsal scales on the tail are quadrangular, imbricate and keeled. Ventral scales on the tail are triangular, smooth and imbricate.

Color and pattern in preservative. It lacks pattern. The dorsal region is uniformly brownish, with the dorsal region of the head darker than the rest of the body. From the groin, towards the posterior dorsal part of the body, a few white scales are scattered, not going further than the middle of the trunk. The ventral coloration is light gray.

Variation in the paratypes. Body measurements were divided into males and females (holotype is included within the males): Mean and extreme values, in mm, for the males (five specimens) are: snout-vent length: 80.17 (72.71–85.5); axilla-groin distance: 38.12 (34.71–41.11); left forelimb length: 31.59 (27.43–33.16); left hindlimb length: 46.18 (42.7–48.85); tail length: 123.5 (112–135); head length: 17.19 (15.42–18.09); head width: 15.21 (13.44–16.24); and head height: 10.26 (9.57–10.78). For the females (six specimens) the measurements are: snoutvent length: 81.61 (78.7–84.8); axilla-groin distance: 38.92 (36.1–41.9); left forelimb length: 31.72 (29.8–34.4); left hindlimb length: 46.1 (42.8–50.2); tail length: 124 (value of only non-regenerated tail); head length: 17.82 (16.18–19.53); head width: 15.34 (14.15–16.64); and head height: 9.95 (9.52–10.3). No evident sexual dimorphism is observed.

In the five males (including the holotype), the mean and extreme values of the number of scales around midbody are 86.4 (83–90). None has precloacal pores. Two transverse gular folds, including the antehumeral fold, instead of a longitudinal neck fold, are observed in two specimens. The male paratypes exhibit the following variation in squamation with respect to the holotype. Two frontal azygos, with the posterior one being larger, in two specimens. Two longitudinally elongated parietal scales in three specimens, 3 to 5 large supraoculars and 13 to 18 small supraoculars, 5 to 7 superciliaries, 4 to 7 loreal scales, 5 to 6 lorilabials, 5 to 6 supralabials and 5 to 6 infralabials. Slight keels in the dorsal region of the forearm in two specimens. Ventral scales of forearm rounded in two specimens. 18 to19 lamellae on the third finger of the left hand. Scales in the dorsal femoral region are imbricate and with no small granular scales in the interstitial region in one specimen, and imbricate but with granular scales in interstitial region in another specimen. Scales in the dorsal femoral region are slightly keeled in one specimen. Scales in the dorsal tibial region are subimbricate in one specimen and completely imbricate in another. 24 to 27 lamellae on the fourth toe of the left foot. In the females, the mean and extreme values of the number of scales around midbody are 84 (80–93). None has precloacal pores. Two transverse gular folds, including the antehumeral fold, instead of a longitudinal neck fold, are observed in one specimen. In comparison with the holotype the five female paratypes exhibit the following variation. Two frontal azygos, with the posterior one bigger, in three specimens. Six frontonasal scales in one specimen. Longitudinally enlarged frontal scale and short squared postfrontals in two specimens. Squared interparietal scale in one specimen. Two longitudinally elongated parietal scales in four specimens. 4 to 5 large supraocular and 14 to 19 small supraoculars, 6 to 8 superciliaries, 4 to 7 loreals, 6 to 8 lorilabials, 6 to 7 supralabials and 5 to 6 infralabials. Five pairs of postmentals in one specimen. Dorsal scales subimbricate in one specimen. Dorsal scales of the forearm very slightly keeled in three specimens. Ventral scales of the forearm rounded in two specimens. 18 to 21 lamellae in the third finger of the left hand. Dorsal femoral scales imbricate in two specimens, and with poorly developed keels in another specimen. Dorsal tibial scales subimbricate in two specimens. Dorsal scales of the foot slightly keeled in one specimen. 24 to 29 lamellae in the fourth toe of the left foot.

Color variation is poorly visible within the preserved specimens. No kind of sexual dichromatism is observed. Some specimens are clearer, reaching a whitish gray tone, especially in the specimens of the older sample (1985). Perhaps the most pronounced variability is found in the melanism level of the dorsal region of the head, varying from dark brown to almost black. The clear scales scattered towards the dorsum starting from the groin, visible on the holotype, are visible only on the specimens of the newer sample (2011). The ventral region varies from whitish gray to gray. In some specimens a slight yellowish tone on the sides of the posterior half of the ventral region is observed. In all of specimens the ventral region of the head exhibits a pattern consisting of a gray background, mottled with white spots.

Distribution. It has only been registered at the type locality, in an area of the narrow canyon of Las Damas River, between 2012 and 2057 masl. The river ends at the origin of the Tinguiririca River, near the locality of Termas del Flaco, in the Andean area west of the city of San Fernando, in the Libertador Bernardo O’Higgins Region, Chile.

Natural History. Viviparous species. Saxicolous habits, it is found basking over the large rocks that form its natural habitat, with relatively low vegetation. It can also be seen climbing branches of Berberis sp., possibly to eat their flowers (Núñez & Torres-Mura 1992). In the altitudinally lowest part of its distribution it is sympatric with L. curis , and with Phymaturus damasense (Troncoso-Palacios & Lobo 2012) in all of its distribution.

Osteological description. Based on specimen MNHNCL-1964, female, double-stained skeleton. ( Figure 11 )

Cranium features: cranium length (from cephalic condyle to premaxilla) 17.1 mm; cranium width (between sutures of maxilla and jugal) 11.88 mm; cranium height 6,95 mm; orbit length (between lacrimal and premaxilla) 6.78 mm. Anteriorly rounded premaxilla. The maxillar process is shorter than the nasal process (spine) of the premaxilla of the premaxilla; the premaxilla is pierced by two foramina, one on each side. The margin of these foramina is made by the premaxilla and the maxilla; those tiny holes are the passage for the medial ethmoidal nerves (Oelrich 1956). The widest part of the premaxilla is slightly shorter than the nasal spine of the premaxilla. The nasal process is projected backward and rests beneath the anterior junction of the nasal bones. Ventrally, the premaxillae bear six caniniform and pleurodont teeth. Also, ventrally is the incisive process, an antero-inferior projection, which is long, conspicuous and swollen.

Nasal capsules relatively enlarged, medially and anteriorly margined by the nasal process of the premaxilla and by the premaxillar process of the nasal bones; the floor of the nasal capsule is the flat premaxillar process of the maxilla. The nasal capsule has a foramina connected with the choanae. Paired nasal bones, twice as long as wide, medially sutured to each other. The anterior portion of both bones covers the spinal process of the premaxilla as described. Laterally and anteriorly, these are sutured to the ascendant process of the maxilla and, caudally at the wide margin with the prefrontal bones. The nasals, at their posterior margin, broadly diverge to house the anterior tip of the frontal bone. The divergence is located at the level of the anterior margin of the orbit. The dorsal surface of the nasal bone is pierced by five small foramina, which are the passages for the cutaneous branches of the ethmoidal nerve and veins (Oelrich 1956). Also, the surface of the nasal bones is wrinkled, sinuous and carved out by the scales.

Paired prefrontal bones triangular, with an acute projection backwards. The medial margin is broadly sutured to the nasals and anteriorly strongly sutured to the ascendant process of the maxilla and to the tiny lacrimal. Ventrally the prefrontals form the anterior ceiling of the ocular orbit. The prefrontals are deflected downwards, forming the descendant process of the prefrontals, sutured solidly to the palatine bones. This process forms the medial wall of the lacrimal foramen, whose external wall is completely margined by the small lacrimal bone. The descendant process of the prefrontal forms a small part of the orbito-nasal fenestra, which is completely formed by the descendant process of the frontal.

Unpaired flat frontal bone, with a wrinkled surface, product of the overtopping scales. Anteriorly it is sutured to the nasals and prefrontal bones as described. The frontal forms the anterior margin of the ocular orbit. Backwards the frontal diverges widely to join with the parietal. Together, those bones form the epiphyseal foramen. The frontal is weakly sutured to the tiny postfrontal. Ventrally it has a tubular shape housing the olfactory channel. The paired postfrontal bones are laminar, quite small and forming a bridge, connecting the frontal and the postorbital bones.

The parietal is a single bone, sutured anteriorly with the frontal as previously described. It is dorsally flattened with a wrinkled surface. Laterally the parietal is abruptly deflected downwards to form the posterior cranial cage. Anteriorly it has two postorbital processes, sutured to the postorbital bones. Towards the caudal end the parietal is widely spread in the supratemporal processes; these processes are sutured to the respective supratemporal bones and also to the paraoccipital process of the exoccipital. The caudal portion of the supratemporal bones is externally margined by the squamosal bone, medially by the paraoccipital process of the exoccipital, and ventrally by the postero-superior portion of the cephalic condyle of the quadrate bone. The supratemporal bones are projected forward through the inferior margin of the supratemporal process to house the parietal in a groove, as was described by Etheridge (1995). The parietal bone, on its external walls receives the superior tip of the epipterygoid bone, an osseous rod, attached to the pterygoid bone. Length of the temporal fenestra 5.5 mm. Postorbital bones are paired. They are flat bones with three processes, at their anterior margin they form the posterior margin of the orbit, and at their posterior margin, they form the anterior margin of the temporal fenestra. The dorsal (medial) apex of the postorbital joins the postfrontal and parietal as previously described. The anterior process is firmly sutured to the jugal, and at its posterior tip it is weakly sutured to the squamosal bone.

Squamosal bones are paired, and are like curved rods, whose anterior processes are joined to the postorbital, as was described. Their caudal tips are widened, and there is a process projected to a notch on the cephalic condyle of the quadrate, which is pierced by this process. Quadrates are auricular-shaped paired bones. Inferiorly they present a grooved condyle attached to the mandible. Dorsally the quadrate has a cephalic condyle, sutured strongly to the paraoccipital process, to the supratemporal, and to the squamosal, as described. The attachment is weak and made through cartilaginous fibers. Posteriorly and medially there is a column that reaches the very summit of the quadrate: the posterior crista (Oelrich 1956). Close to the lower part of this column the pterygoid valve reaches the quadrate, to which it is attached by cartilaginous fibers. Jugals are two long and curved rods, forming the inferior ridge of the orbit, distally they are strongly sutured to the maxilla and to the tiny lacrimal; the lowest part of the jugal is deflected backwards and upwards and weakly attached to the anterior tip of the postorbital and squamosal by ligaments. Also, in the lowest part, the jugal is strongly attached to the ectopterygoid. On the external surface it exhibits four conspicuous foramina.

Maxillae are paired bones, roughly triangular. The anterior process is sutured to the premaxilla as described. Medially, and as a part of the floor of the nasal concha it is sutured to the septomaxilla. This maxilla has cartilage covering the nasal concha. The ascendant process is strongly sutured to the nasal, to the lacrimal, and to the jugal. The external surface has eight foramina; the four on the lower part arranged in a line, and the most caudal is the biggest. The maxilla bears 16 pleurodont teeth in deep cavities. Teeth 1 y 12 are tricuspideous, 13 to 16 are caniniform, the transition is gradual. Ventrally and anteriorly, the maxilla is strongly attached, with a few extensions, to the vomer bones. Also ventrally, the maxilla forms a wide arc whose apex is strongly sutured to the maxillar process of the palatine bones, and together these bones form the caudal margin of the exochoanal fenestra. The maxilla is slightly deflected outwards, forming the external margin of the infraorbital fenestra. Its caudal portion is solidly sutured to the jugal and to the ectopterygoid. Dorsally the maxilla is projected at the level of the tooth 3. In this specimen, the anterior tip of the ectopterygoid is truncated.

Vomer bones are paired and medially sutured. Anteriorly they are sutured to the premaxilla as described. Vomers are sutured to the vomerian processes with a strong attachment, converging forward and medially. Vomers form the medial margin of the exochoanal fenestra, and at the middle and caudally they form a recess. Palatine bones are paired, laminar and with two anterior processes. The medial vomerian processes are sutured to the vomers as described. Palatines are not sutured to each other and they caudally diverge to form the piriform recess. They are projected toward the sides to suture with the ptetygoid bones, and together they form the ceiling of the palatal roof. The attachment to the pterygoid is biased. Dorsally the palatine bones are sutured to the descendent process of the prefrontal, see above. The broader area of the piriform is formed by the divergent caudal branches of the pterygoids.

Pterygoid bones are paired, distally they are sutured to the palatines as described. In the external lateral area, the pterygoid has an ectopterygoid process sutured to the ectopterygoid bone, forming a strong bridge. There is a third process projected caudally, making contact with the quadrate just above the basal condyle; this process of the pterygoid is valve-like shaped. The pterygoid bones have, on the ventral face, a cavity with six pterygoid caniniform teeth, slanted downwards and inwards. The pterygoid has a notch on its posterior half, on it is inserted the thin rod-like epipterygoid, and behind this notch there is a small groove that holds the processes of the basisphenoid bone.

The basisphenoid is a single bone, medially located, and is forward projected with the basipterygoid processes as described above. The basisphenoid is fused with the basioccipital. The basisphenoid is projected into the piriform recess and forward to a thin stalk, called the basisphenoid process. The basioccipital is a single bone, bearing the occipital condyle. A pair of eminences, the sphenoccipital tubercles, are projected downwards, emerging at the front and to the sides of the condyle. The recessus jugularis is a winged body with a cavity projected forward in the oticoccipital part. The bones of the posterior face of the head are fused around the big foramen magnum. The supraoccipital has a slight crest.

The mandible: the dentary bears 20 teeth; teeth 1 to 17 are tricuspid, and 18, 19 and 20 are caniniform, housed in deep cavities in the crista dentalis. Teeth are typically pleurodont. The dentary, on its distal end, ventrally presents a very slight opening of Meckel’s groove. Caudally and through a lingual aspect, the dentary diverges to suture with the splenial. Both bones form the antero-inferior alveolar foramen (See Oelrich 1956) at the level of teeth 5 and 6. The dentary is deflected upwards, riding on the splenial process of the coronoid bone. The dentary projects its length, through the ventral region of the mandible, beyond the coronoid bone to suture with the angular and the suprangular bone. The coronoid rides on the dentary and on the splenial, and at its posterior portion it is sutured to the suprangular. The suprangular has a large cavity: the mandibular foramen. The articular is the most proximal bone, and has notches to receive the quadrate as previously described.

The hyoids set: The hyoid is a set of thin rod-like processes. Forward, the body of the hyoid is projected as the hypohial; backwards this body diverges into two branches: the ceratobranchials 2 (see de Queiroz 1987). Fused and towards the sides, on the anterior part of the body, the basihials are projected in a slanted position. From the posterior part of the body two curved branches, the ceratobranchials 1 (ibid.), broadly diverge to the sides of the neck, reaching the quadrate. On the external margin of the basihials, the ceratohials are attached, whose anterior and internal margins are expanded inwards with alar processes of cartilaginous nature.

The tibia shows the typical form of the Liolaemus (Lioaemus) sensu stricto subgenus, i.e., without a tibial blade, and with a circular section.

Phylogenetic analysis (See Fig. 12). Of the 141 morphological traits used in the tree, 98 are fixed, 21 are parsimoniously uninformative, and only 22 are parsimoniously informative. Most of the nodes have bootstrap values below 50, except the node including the ingroup, with a value of 74; the one including all of the ingroup except for L. elongatus , with a value of 65; the one including L. flavipiceus , L. carlosgarini and L. buergeri from the type locality (El Planchón), with a value of 52; the one including L. carlosgarini and L. buergeri (from El Planchón) with a value of 62; and finally the most supported clade formed by L. riodamas and L. cristiani , with a value of 84.

Figures

FIGURE 6. — Holotype of Liolaemus riodamas. MNHNCL- 4684

FIGURE 11. — MP Cladogram of the Liolaemus species used in this study. The values on the nodes correspond to Bootstrap values. Nodes with no values on them correspond to Bootstrap values below 50. The tree has a Consistency Index of 0. 64, and a re-escalated Consistency Index of 0. 4213.