DNA sequence indicates the Lacertidae contain two subfamilies, Gallotiinae and Lacertinae, the latter comprising two monophyletic tribes, the Eremiadini of Africa and arid southwest and central Asia, and the Lacertini of Europe, northwest Africa and southwest and east Asia. Relationships within the 108 species of Lacertini are explored using mtDNA (291 bp cytochrome b; 329 bp 12S rRNA for 59 nominal species, and reanalysis of the data of Harris et al. 1998, and Fu 2000). The morphology of the tribe is reviewed and 64 of its characters (equivalent to 83 binary ones) also used to assess relationships. The Lacertini are assigned to 19 monophyletic units of 1 to 27 species, recognised here as the following genera (contents are indicated in brackets): Algyroides, Anatololacerta gen. nov. (L. danfordi group), Apathya (L. cappadocica group), Archaeolacerta (L. bedriagae), Dalmatolacerta gen. nov. (L. oxycephala), Darevskia (L. saxicola group), Dinarolacerta gen. nov. (L. mosorensis), Hellenolacerta gen. nov. (L. graeca), Iberolacerta (L. monticola group), Iranolacerta gen. nov. (L. brandtii and L. zagrosica), Lacerta s. str. (sand and green lizards, L. agilis group), Parvilacerta gen. nov. (L. parva and L. fraasii), Phoenicolacerta gen. nov. (L. laevis group), Podarcis (wall lizards), Scelarcis (L. perspicillata), Takydromus (Asian grass lizards), Teira (L. dugesii), Timon (ocellated lizards, L. lepida group) and Zootoca (L. vivipara). Both mtDNA and morphology indicate that Lacerta and Timon are sister taxa, and DNA suggests further possible relationships among genera (Fig. 1, p. 6). Neither DNA nor morphology indicates that the archaeolacertas (sometimes formalised as Archaeolacerta sens. lat.) form a clade. Instead, they are representatives of an ecomorph associated with living on rock exposures and using the narrow crevices that these contain. The Lacertidae probably arose in the European area, with the Gallotiinae later reaching Northwest Africa and the Canary Islands, and the ancestor of the Eremiadini invading Africa in the mid-Miocene. The Lacertini spread through much of their present European range and diversified, perhaps largely by repeated vicariance, around 12–16 My ago, producing the ancestors of the present mainly small-bodied genera, which then underwent often modest speciation. Three units spread more widely: the Lacerta-Timon clade of large-bodied lizards probably dispersed earliest, followed by Algyroides and then Podarcis. Overall, European Lacertidae show a pattern of repeated spread, often accompanied by restriction of previous groups. Expansion of Lacertini may have displaced earlier lacertid lineages from all or much of Europe; while spread of Podarcis may have restricted many other genera of Lacertini. The earlier expansion of the Lacerta-Timon clade probably did not have this effect, as difference in adult body size restricted competitive interaction with other forms. Several invasions of more distant areas also occurred: of East Asia by Takydromus over 10 My ago, and more recently of northwest Africa by Podarcis, Scelarcis and Timon, and Madeira by Teira. Relationships within the Eremiadini estimated from both mtDNA, and nDNA differ considerably from those based on morphology. They indicate relatively mesic forms may have diversified widely across Africa and given rise to at least three independent invasions of arid habitats. MtDNA also indicates that Lacerta andreanskyi belongs in the Eremiadini and may occupy a basal position there. It is assigned to a further new genus, Atlantolacerta gen. nov.

In most zoological textbooks, Platyhelminthes are depicted as an early-emerging clade forming the likely sister group of all the other Bilateria. Other phylogenetic proposals see them either as the sister group of most of the Protostomia or as a group derived from protostome coelomate ancestors by progenesis. The main difficulty in their correct phylogenetic placing is the lack of convincing synapomorphies for all Platyhelminthes, which may indicate that they are polyphyletic. Moreover, their internal phylogenetic relationships are still uncertain. To test these hypotheses, new complete 18S rDNA sequences from 13 species of "Turbellaria" have been obtained and compared to published sequences of 2 other "Turbellaria," 3 species of parasitic Platyhelminthes, and several diploblastic and deuterostome and protostome triploblastics. Maximum-parsimony, maximum-likelihood, and neighbor-joining methods were used to infer their phylogeny. The results show the order Catenulida to form an independent early-branching clade and emerge as a potential sister group of the rest of the Bilateria, while the rest of Platyhelminthes (Rhabditophora), which includes the parasites, form a clear monophyletic group closely related to the protostomes. The order Acoela, morphologically considered as candidates to be ancestral, are shown to be fast-clock organisms for the 18S rDNA gene. Hence, long-branching of acoels and insufficient sampling of catenulids and acoels leave their position still unresolved and call for further studies. Within the Rhabditophora, our analyses suggest (1) a close relationship between orders Macrostomida and Polycladida, forming a clear sister group to the rest of orders; (2) that parasitic platyhelminthes appeared early in the evolution of the group and form a sister group to a still-unresolved clade made by Nemertodermatida, Lecithoepitheliata, Prolecithophora, Proseriata, Tricladida, and Rhabdocoela; and (3) that Seriata is paraphyletic.

Sequences of 18S ribosomal DNA (rDNA) are increasingly being used to infer phylogenetic relationships among living taxa. Although the 18S rDNA belongs to a multigene family, all its copies are kept homogeneous by concerted evolution (Dover 1982; Hillis and Dixon 1991). To date, there is only one well-characterized exception to this rule, the protozoan Plasmodium (Gunderson et al. 1987; Waters, Syin, and McCutchan 1989; Qari et al. 1994). Here we report the 1st case of 18S rDNA polymorphism within a metazoan species. Two types (I and II) of 18S rDNA have been found and sequenced in the platyhelminth Dugesia (Schmidtea) mediterranea (Turbellaria, Seriata, Tricladida). Southern blot analysis suggested that both types of rDNA are present in the genome of this flatworm. This was confirmed through sequence comparisons and phylogenetic analysis using the neighbor-joining method and bootstrap test. Although secondary structure analysis suggests that both types are functional, only type I seems to be transcribed to RNA, as demonstrated by Northern blot analysis. The finding of different types of 18S rDNAs in a single genome stresses the need for analyzing a large number of clones whenever 18S sequences obtained by PCR amplification and cloning are being used in phylogenetic reconstruction.

Morphological systematics makes it clear that many non-volant animal groups have undergone extensive transmarine dispersal with subsequent radiation in new, often island, areas. However, details of such events are often lacking. Here we use partial DNA sequences derived from the mitochondrial cytochrome b and 12S rRNA genes (up to 684 and 320 bp, respectively) to trace migration and speciation in Tarentola geckos, a primarily North African clade which has invaded many of the warmer islands in the North Atlantic Ocean. There were four main invasions of archipelagos presumably by rafting. (i) The subgenus Neotarentola reached Cuba up to 23 million years (Myr) ago, apparently via the North Equatorial current, a journey of at least 6000 km. (ii) The subgenus Tarentola invaded the eastern Canary Islands relatively recently covering a minimum of 120 km. (iii) The subgenus Makariogecko got to Gran Canaria and the western Canary Islands 7-17.5 Myr ago, either directly from the mainland or via the Selvages or the archipelago of Madeira, an excursion of 200-1200 km. (iv) A single species of Makariogecko from Gomera or Tenerife in the western Canaries made the 1400 km journey to the Cape Verde Islands tip to 7 Myr ago by way of the south-running Canary current. Many journeys have also occurred within archipelagos, a minimum of five taking place in the Canaries and perhaps 16 in the Cape Verde Islands. Occupation of the Cape Verde archipelago first involved an island in the northern group, perhaps São Nicolau, with subsequent spread to its close neighbours. The eastern and southern islands were colonized from these northern islands, at least two invasions widely separated in time being involved. While there are just three allopatric species of Makariogecko in the Canaries, the single invader of the Cape Verde Islands radiated into five, most of the islands being inhabited by two of these which differ in size. While size difference may possibly be a product of character displacement in the northern islands, taxa of different sizes reached the southern islands independently.