Liolaemus (Etheridge, 1995)

Pincheira-Donoso, Daniel, Scolaro, J. Alejandro & Sura, Piotr, 2008, A monographic catalogue on the systematics and phylogeny of the South American iguanian lizard family Liolaemidae (Squamata, Iguania), Zootaxa 1800, pp. 1-85 : 15-17

Liolaemus genus

In the recent decades, Laurent (1983, 1985b, 1992) was the first author that formulated an explicit and powerful hypothesis on the phylogenetic relationships of higher groups among Liolaemus lizards. After performing a series of statistical analyses on previously overlooked and underestimated morphological traits, he found that these lizards can be separated into two major groups, one mainly Andean-occidental and one Andean-oriental. Morphologically, the occidental group, called by Laurent (1985b, 1992) “Chilean group”, includes species characterized by narrow supralabial scales, usually four or fewer, the last one elongated and upturned in its posterior margin, and with a low number of precloacal glands (= preanal pores), usually four or fewer (see Etheridge 1995). This group of taxa was placed by Laurent (1985b, 1992) into the subgenus Liolaemus (sensu stricto). Species belonging to the oriental group, called “Argentinean group”, exhibit short supralabial scales, usually five or more, the last one is not upturned posteriorly, a high number of precloacal glands, usually five or more (up to 12), the puboischiotibialis muscle (flexor tibialis internus fide Abdala, V. et al. 2006) hypertrophied, and a conspicuous sharp, blade-like process on the tibia (see Etheridge 1995; also Núñez et al. 2000). This complex of species was recognized under the subgenus Eulaemus ( Laurent 1992; see also Etheridge 1995). More recently, additional morphological evidence led Etheridge (1995) to support this classification model, who also recognized that a series of species grouped into the Eulaemus subgenus exhibit a unique patch of enlarged scales on the posterior surface of the thigh. These lizards were then recognized as the boulengeri complex (see Cei 1993; Etheridge 1995, 2000; Halloy et al. 1998; Pincheira-Donoso & Núñez 2005; Abdala 2007, for details). Remarkably, these groups of species have remained largely accepted, and more importantly, have recently been supported by phylogenetic hypotheses constructed on both morphological and molecular evidence (e.g. Etheridge 2000; Schulte et al. 2000; Espinoza et al. 2004; Cruz et al. 2005; Abdala 2007).

Even though Laurent (1983, 1985b, 1992) and Etheridge (1995) reported pioneer evidence to hypothesize relationships among higher-level groups within Liolaemus , the first explicit phylogenetic study focusing on the relationships among species within these clades was only recently published ( Schulte et al. 2000; see also Schulte et al. 1998). Schulte et al. ’s (2000) molecular phylogeny supported substantially the hypothesis of a major event of Liolaemus diversification into two main clades, the subgenus Liolaemus and the series signifier (indicated by Schulte et al. as subgenus Eulaemus ). In addition, this phylogenetic study provided the first empirical evidence to test the hypothesis that austral Liolaemus species recognized as members of the groups archeforus and kingii ( Scolaro & Cei 1997) may represent primitive Patagonian states in the evolutionary history of this genus ( Laurent 1985b; see also Cei 1986). According to Laurent (1985b), morphological peculiarities observed in these austral species would be indicative of their ancestral position within Liolaemus (see also Etheridge 1995). However, Schulte et al. ’s (2000) results rejected such claims. Indeed, this phylogeny revealed that the archeforus-kingii line (i.e. subgenus Donosolaemus ) would be related to the Eulaemus subgenus, and therefore, that it originated after the first main diversification event experienced by this genus, during the Tertiary (e.g. Pincheira-Donoso & Núñez 2003). Later phylogenetic studies have provided, in general, similar results in relation to the relationships among subgenera, among clades within subgenera (e.g. groups alticolor , elongatus-kriegi, boulengeri ), and among series of species (e.g. Avila et al. 2004; Espinoza et al. 2004; Morando et al. 2004; Cruz et al. 2005; Abdala 2007; Pincheira-Donoso et al. 2007a; see also Lobo 2001; Díaz & Lobo 2006, for morphological based phylogenies).

In spite of an increasing number of studies exploring relationships among Liolaemus taxa published over the last few years, many aspects of the phylogeny of this lineage remain still controversial. For example, the position in the phylogenetic structure of the genus Liolaemus of L. pseudoanomalus , a species recognized by Cei (e.g. 1986, 1993; see also Laurent 1984a; Núñez & Yáñez 1984b) as a member of the anomalus group, tends to show substantial discordance among different studies (e.g. Schulte et al. 2004; Espinoza et al. 2004; Abdala 2007; Pincheira-Donoso et al. 2007a). More importantly, the phylogenetic relationships between a large number of Liolaemus species remain to be studied for the first time.