Phymaturus camilae, Scolaro, J. Alejandro, Jara, Manuel & Pincheira-Donoso, Daniel, 2013

Scolaro, J. Alejandro, Jara, Manuel & Pincheira-Donoso, Daniel, 2013, The sexual signals of speciation? A new sexually dimorphic Phymaturus species of the patagonicus clade from Patagonia Argentina, Zootaxa 3722 (3), pp. 317-332 : 322-327

Phymaturus camilae sp. nov.

( Figures 4 , 5 )

Type material. Holotype: MLP-R. 5786, adult male, collected in volcanic rocky outcrops (1100 m asl) of Sacanana stream bridge, adjacent to Provincial Road 4, (42º27'55.4”S, 68º43'33.3”W), Chubut Province, Argentina. Collected by J.A. Scolaro and O.F. Tappari, 0 5 February 2010.

Paratypes: MLP-R 5787, adult female; MLP-R 5788, adult male; MLP-R 5789 adult female; UNCo-PH 1614, adult female; UNCo-PH 1308 adult male; JAS-DC 1316 adult male; JAS-DC 1318 adult male; JAS-DC 1320, adult male; JAS-DC 1609 adult female. The same data as the holotype.

Etymology. The species is named after Camila Antonia, the daughter of DPD. The suggested English common name for this species is ‘Camila’s Patagonian Rocky Lizard’, and in Spanish ‘Matuasto de Camila’.

Diagnosis. Phymaturus camilae sp. nov. is characterized by pronounced sexual dichromatism (and sexual size dimorphism, with females being the larger sex), an unusual pattern of intersexual differentiation within the clade patagonicus , in which species show a clear tendency toward monochromatism. As we stated above, and as confirmed by Morando et al. (2013), Phymaturus camilae sp. nov. is a member of the patagonicus clade, and hence, it can be distinguished from species of the palluma clade by the traits detailed in Etheridge (1995). Also, as detailed in the results section above, the phylogenetically closest relatives of Phymaturus camilae sp. nov. are P. calcogaster and P. patagonicus . While P. patagonicus lacks sexual dichromatism, this intersexual trait is clearly expressed in our new species. In addition, both species differ substantially in the overall patterns of coloration. Phymaturus camilae sp. nov. shares multiple phenotypic similarities with P. calcogaster , although in this latter species sexual dichromatism and sexual size dimorphism are only slightly expressed, while both are evident in the new species ( Figs. 2 b, 4, 5). Finally, as detailed in the results section, the molecular evidence presented by Morando et al. (2013) reveals that Phymaturus camilae sp. nov. has genetically diverged from the two related species, providing further confirmation of our new species hypothesis.

Description of the holotype. A medium-sized Phymaturus . Snout-vent length (SVL) 85.2 mm; tail 104.6 mm; head length 16.4 mm; head width 16.6 mm; eye-nose distance 6.1 mm; forelimb length measured from to the insertion of the limb into the body wall to the end of the claw of the fourth finger, 35.3 mm; hind limb length measured from to the insertion of the limb into the body wall to the end of the claw of the fourth toe, 47.0 mm; axilla-groin distance 43.9 mm (51.5 % of SVL); fourth finger length 9.4 mm; fourth toe length 14.1 mm; scales in dorsal head 24; scales around midbody 228; ventral scales between mental and precloacal pores 164; scales between rostral and frontal 12; supralabial scales 9-8; infralabial scales 7–8; subdigital lamellae on fourth finger 24; subdigital lamellae on fourth toe 31; precloacal pores 9; cephalic scales subpentagonals, smooth; supraorbital semicircles with large bulky scales, rounded, separated by a line of three small rounded scales, without azygous, incomplete posteriorly on both sides; indistinct rounded supraoculars; 6-6 imbricate and enlarged upper ciliaries; subocular scales rectangular not fragmented, shorter than eye diameter, separated from supralabials by 2-2 irregular rows of lorilabials; preocular in contact with first lorilabial row; canthal separated from nasal by 2–3 scales; temporals smooth and rounded irregularly coniform, in 8–9 row scales from auditive opening to the subocular; external auditory meatus enlarged, subellipsoidal longitudinally, with 6–7 more protruding and conically enlarged scales on its anterior border; tiny granular scales on posterior border; rostral undivided, wider than higher, separated by one row of medium scales from nasals; nasal large and surrounded by 7–8 small and irregular scales; nasals separated by four small irregular scales; nostril rounded and large, over the centre of nasal scale; parietals irregular and rough with evident interparietal, surrounded by seven scales; nuchals strongly conical in 7–8 irregular rows; post-auricular folds very developed with smooth granular scales; mental subpentagonal shorter in width but higher than rostral, contacting with four irregular almost rectangular scales; two rows of 6–7 bilateral postmentals decreasing behind; dorsal scales smooth, granular, small and juxtaposed; mid-dorsal scales slightly rounded and smooth, decreasingly smaller and strongly rounded toward the flanks; ventro-laterals and ventrals larger than dorsals, almost pentagonal, imbricate and smooth, slightly pointed; two gular folds with rounded, small scales; 63 gulars between auditory meatus; caudal scales quadrangular and regularly imbricate in verticiles, proximally large, conical and smooth on dorsum, or slightly keeled, distally more rectangular and strongly keeled; scales on forelimbs sutriangular and smooth in the upper side, granular, rounded and subconical in the underside; scales in hind limbs strongly conical and slightly keeled in the dorsum but larger subpentagonal, imbricate and flat in the underside; in the femoral region, small granular scales in the lower side; infracarpals and infratarsals with round margins, becoming keeled to the base of fingers and toes. Subdigital lamellae of fingers keeled; fourth toe and finger claws very developed, almost 2.5–3.0 mm of long.

Species coloration ( Figs. 4 , 5 ). The overaIl dorsal pattern of coloration consists of a dark-brown background characterized by an irregular design of tiny light-brown or whitish spots (each of which covers a surface of about 5–6 scales). This pattern extends over the entire dorsal surface of the body, including the limbs. The tail is generally brown or greyish, and tends to be lighter than the rest of the dorsal body, with whitish spots that can merge to form larger whitish areas. In males, the dark dorsal background tends to be highly homogeneous, although in some specimens it is more heterogeneous as a result of the (generally) sides of the dorsal surface showing darker, irregularly spread, pigment ( Figs. 4 , 5 ). In females, the dorsal coloration is considerably more irregular than in males, and a wide spectrum of pattern variation can be observed ( Fig. 5 ). In some females, there are two slightly diffuse longitudinal and parallel rows of whitish spots on the dark-brown background. In other females, the sides of the dorsal surface are strongly darker, which results in a lighter (brownish, greyish or whitish) area running on the vertebral surface of the body, which, as the rest of the dorsal surface, is irregularly spotted. The darker sides can often extend over the whiter centre of the dorsal surface in the form of an irregular reticulation. The ventral surface is consistently light, often whitish or pale-gray with pale-orange shades (although these shades can be very intense in some individuals), in both males and females. In both sexes too, the ventral surface of the head shows a blackish irregular and fine reticulation that rarely extends beyond the neck line. The ventral surface of the tail is slightly darker. In preservation, specimens experience a visible loss of the coloration observed in life, especially in the orange shades of the ventral surface of the body.

Morphological variation. The sample analyzed consists of 17 adult specimens (10 males and 7 females; see Tables 1 & 2, for body measures). Our quantitative analyses of body size between both sexes reveals significant sexual size dimorphism, females being the larger sex (mean SVL Females = 95.8 mm, range = 92.2–101.7 mm, SD = 2.8; mean SVL Males = 88.7 mm, range = 85.2–93.8, SD = 3.0). Axilla-groin distance in females ranged 46.6–55.7 mm (mean = 49.3 mm, SD = 2.9, representing 49.6–54.7% of SVL); in males ranged = 43.1–48.0 mm (mean = 44.9; SD = 2.4, representing 49.7–52.1% of SVL), and showing significative differences in females (t = 3.91, P <0.001). Head length ranged 15.7–17.5 mm. Head width ranged 15.4–17.7 mm. Eye-nose distance ranged 6.0– 6.9 mm. Tail length ranged 103.0–125.0 mm (n = 11) representing 1.03–1.28 times of SVL. Forelimb length ranged 30.7–35.3 mm. Mean of hindlimb length in males was 47.4 mm, but in females ranged 44.7–47.1 mm (mean = 45.9 mm). Scales around midbody ranged 205–228. Dorsal head scales ranged 20–24. Ventrals ranged 159–187. Precloacal pores only in males ranged 8–11. Not fragmented subocular scales except in only two cases in 1–2. Two rows of lorilabials between suboculars and supralabials. Scales surrounding interparietal: 6–9. Scales contacting mental: 4–6. Scales between rostral-interparietal: 12. Fourth finger subdigital lamellae number: 21–25. Fourth toe subdigital lamellae number: 26–33.

Geographic distribution. Known distribution of Phymaturus camilae sp. nov. ( Fig. 1 ).

Natural history. Phymaturus camilae sp. nov. occurs in the arid Patagonian phytogeographic province. In these ecosystems, the mean annual environmental temperature is ~14ºC, while the annual precipitation rarely reaches the 250 mm. Predominantly, this area of Patagonia consists of shrub-steppe, where shrub coverture is scattered (~50% of the surface), with dwarf cushion shrubs and scarce grassy patches. Bushes are primarily represented by Nassauvia glomerulosa , Senecio filaginoides , Ephedra frustillata , Adesmia volkmanii , Mulinum spinosum , Lycium chilense and Lycium gillesianum . This steppe landscape can occasionally be altered by volcanic scoria resulting from the intense volcanic activities of the past. Interestingly, these deposits of volcanic scoria constitute the exclusive biotope of Phymaturus camilae sp. nov.

Phymaturus camilae sp. nov. occupies a restricted rocky microhabitat ( Fig. 6 ). In its area of distribution, the new species coexists (sometimes on the same rocky systems) with multiple other lizard species, primarily members of the Liolaemus genus ( Liolaemus bibroni , L. ceii , L. elongatus , L. rothi , L. uptoni ), some Leiosaurids ( Diplolaemus darwinii , D. sexcinctus and Pristidactylus nigroiugulus ) and the Phyllodactylidae Homonota darwinii . Given that Phymaturus camilae sp. nov. tends to exclusively occupy the rocky outcrops, only a few individuals of these other species can be found in actual syntopy with the new species. After multiple field trips in the area, no species of snakes have been found.

Phymaturus camilae sp. nov., consistent with all other known species of the genus, has viviparous reproduction. Based on data from the studied specimens, we observed four females giving birth in captivity late (17th _ 30th) in March 2011. Invariable, litter size consisted of two offspring per female. Finally, the new Phymaturus species was observed in the field feeding on different genera of plants ( Lycium sp. and Adesmia sp.) which suggests an herbivorous trophic ecology. Although the consumption of animal prey cannot be ruled out at present, we argue that (at least predominant) herbivory is the most parsimonious assumption given that the rest of the species of the genus are consistently herbivorous.

Figures

FIGURE 1. Geographic distribution of the Phymaturus species of the calcogaster group in Patagonia Argentina. (a) Distribution of phylogenetically related species of the patagonicus clade hypothesized to belong to the calcogaster group, plus the distribution of P. ceii (the arrow indicates the type locality of P. camilae sp. nov.). The three subsequent maps show the geographic distribution of species of the calcogaster group in relation to elevation (b), mean annual temperature (c), and normalized difference vegetation index, NDVI (d).

FIGURE 2. Comparative morphological analyses between Phymaturus camilae sp. nov. and its closest phylogenetically related species. (a) Distribution of Phymaturus camilae sp. nov. (blue), P. calcogaster (red) and P. patagonicus (green) on a multivariate morphospace based on three principal components of a PCA; (b) differences in the extent of sexual size dimorphism between Phymaturus camilae sp. nov. and P. calcogaster.

FIGURE 4. Phymaturus camilae sp. nov., male (a) and female (b) in dorsal view, from the type locality.

FIGURE 5. Colour pattern variation among preserved males (a) and females (b) of Phymaturus camilae sp. nov. from the type locality.

FIGURE 6. Environment occupied by Phymaturus camilae sp. nov. Picture taken by J. A. Scolaro at the type locality.

Tables

TABLE 1. Mean and range of variation of multiple morphometric (all in mm) and meristic traits in Phymaturus camilae sp. nov., shown separately for males and females.

Variable Snout-vent length (SVL)	Males (N = 10) Mean Range 88.7 85.2–93.8	Females (N = 7) Mean Range 95.8 92.2–101.7
Axilla-groin distance Head length Head width	44.9 43.1–48.1 16.5 16.1–17.5 16.7 15.8–17.7	49.3 46.6–55.7 16.2 15.7–16.8 16.0 15.4–16.7
Eye-nose distance Forelimb length Hindlimb length	6.4 6.1–6.7 33.4 30.7–35.3 47.4 45.2–50.5	6.4 6.0–6.9 33.0 32.2–34.1 45.9 44.7–47.1
Fourth finger length Fourth toe length Dorsals in Head-Length	10.0 9.4–10.9 13.8 13.3–14.7 22.1 20–24	9.5 8.6–10.0 13.0 12.4–13.6 22.0 20–24
Scales surrounding interparietal Fourth toe subdigital lamellae Fourth finger subdigital lamellae	12 12–12 24.3 22–26 29 27–31	12 12–12 23.0 21–25 28 26–29
Supralabial scale number Infralabial scale number Scales contacting mental	8.5 8–9 8.6 7–9 4.9 4–6	8.5 8–9 8.3 7–9 4.6 4–6
Subocular scales Lorilabial rows	1.2 1–2 2.1 2–3	1.1 1–2 2.1 2–3