Marine iguanas are among the most highly emblematic taxa of the Galápagos archipelago but have paradoxically received little attention from taxonomists. Amblyrhynchus is currently considered as a monotypic genus with a total of seven subspecies, A. cristatus cristatus, A. c. nanus, A. c. venustissimus, A. c. albemarlensis, A. c. hassi, A. c. mertensi and A. c. sielmanni. Although consensually followed for more than half a century, this classification does not properly reflect the main natural subdivisions inferred by more recent molecular evolutionary studies. We integrate population genetics, phylogenomics and comparative morphology to propose an updated taxonomy reflecting the evolutionary history of this group. We recognize a single species with 11 divergent population clusters at the level of subspecies: A. c. albermarlensis is recognized as a junior synonym of A. c. cristatus, and five new subspecies are described: A. c. godzilla subsp. nov. (San Cristóbal-Punta Pitt), A. c. jeffreysi subsp. nov. (Wolf and Darwin), A. c. hayampi subsp. nov. (Marchena), A. c. trillmichi subsp. nov. (Santa Fé) and A. c. wikelskii subsp. nov. (Santiago). Recognizing the genetically divergent population clusters as subspecies also highlights several of them as management units in need of conservation efforts, such as the two subspecies endemic to San Cristóbal.

SUMMARY: Blood parasites such as haemogregarines and haemosporidians have been identified in almost all groups of vertebrates and may cause serious damages to their hosts. However, very little is known about biodiversity of these parasites and their effects on some groups of reptiles such as terrapins. Moreover, the information on virulence from blood parasites mixed infection is largely unknown in reptiles. With this aim, we investigated for the first time the prevalence and genetic diversity of blood parasites from one genus of haemoparasitic aplicomplexan (Hepatozoon) in two populations of Spanish terrapins(Mauremys leprosa), a semi-aquatic turtle from southwestern Europe with a vulnerable conservation status. We also examined the association between mixed blood parasite infection and indicators of health of terrapins (body condition, haematocrit values and immune response). Blood parasite infection withHepatozoonspp was detected in 46·4% of 140 examined terrapins. The prevalence of blood parasites infection differed between populations. We found two different lineages of blood parasite, which have not been found in previous studies. Of the turtles with infection, 5·7% harboured mixed infection by the two lineages. There was no difference in body condition between uninfected, single-infected and mixed-infected turtles, but mixed-infected individuals had the lowest values of haematocrit, thus revealing the negative effects of blood parasite mixed infections. Immune response varied among terrapins with different infection status, where mixed infected individuals had higher immune response than uninfected or single-infected terrapins.