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[dinosaur] Eocene lizards from Spain + marine iguanas + last European varanid






Ben Creisler
bcreisler@gmail.com


Some recent lizard stuff that may be of interest:

Free pdf:

Arnau Bolet (2017)
First early Eocene lizards from Spain and a study of the compositional changes between late Mesozoic and early Cenozoic Iberian lizard assemblages. 
Palaeontologia Electronica 20.2.20A: 1-22
doi: palaeo-electronica.org/content/2017/1851-early-eocene-lizards
http://palaeo-electronica.org/content/2017/1851-early-eocene-lizards


Lizard and amphisbaenian fossil material is described for the first time from early Eocene localities in Spain, more specifically from Catalonia (north-eastern Iberian Peninsula). Material is fragmentary and scarce, but diagnostic enough to provide a first approach to the composition of lizard assemblages. The following taxa are recorded: Geiseltaliellus and a second indeterminate pleurodont iguanid; an agamid similar to “Tinosaurus”; an indeterminate gekkotan; a scincoid, possibly scincid lizard; a lacertid similar to Dormaalisaurus; an indeterminate amphisbaenian; a glyptosaurin glyptosaurine (cf. Placosaurus); an indeterminate anguine; and, finally, an indeterminate “necrosaur.” The studied localities range from the MP8+9 to the MP10, and thus complement the only previously known lizard locality of the Iberian early Eocene, the Portuguese locality of Silveirinha, which corresponds to the MP7. An analysis of the composition of these new assemblages suggests a great amount of homogeneity through the different levels of the early Eocene, and also between Iberian and contemporaneous assemblages from the rest of Europe. The lack of an Iberian Paleocene record for lizards strengthens the importance of the study of early Eocene assemblages because these are the only ones available for comparison with Cretaceous associations, providing critical information on the changes in composition between Mesozoic and early Cenozoic lizard faunas related to the K/Pg extinction event.

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Free pdf:


Aurélien Miralles,  Amy Macleod,  Ariel Rodríguez,  Alejandro Ibáñez, Gustavo Jiménez-Uzcategui,  Galo Quezada,  Miguel Vences & Sebastian Steinfartz (2017)
Shedding light on the Imps of Darkness: an integrative taxonomic revision of the Galápagos marine iguanas (genus Amblyrhynchus) 
Zoological Journal of the Linnean Society (advance online publication)
DOI: https://doi.org/10.1093/zoolinnean/zlx007
https://academic.oup.com/zoolinnean/article/3795677/Shedding-light-on-the-Imps-of-Darkness-an



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.


News:

Godzilla of the Galápagos and other speciation stories

https://blog.oup.com/2017/05/godzilla-galapagos-speciation/

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Planet Earth 2--amazing footage of snakes trying to catch hatchling baby marine iguanas as they race to the rocks and the shore; series just won an award in Britain

https://www.youtube.com/watch?v=Rv9hn4IGofM


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Georgios L. Georgalis, Andrea Villa & Massimo Delfino (2017)
The last European varanid: demise and extinction of monitor lizards (Squamata, Varanidae) from Europe. 
Journal of Vertebrate Paleontology article: e1301946. (advance publication)
DOI: 10.1080/02724634.2017.1301946
http://www.tandfonline.com/doi/full/10.1080/02724634.2017.1301946



Remains of a varanid lizard from the middle Pleistocene of the Tourkobounia 5 locality near Athens, Greece are described. The new material comprises cranial elements only (one maxilla, one dentary, and one tooth) and is attributed to Varanus, the genus to which all European Neogene varanid occurrences have been assigned. Previously, the youngest undisputed varanid from Europe had been recovered from upper Pliocene sediments. The new Greek fossils therefore constitute the youngest records of this clade from the continent. Despite being fragmentary, this new material enhances our understanding of the cranial anatomy of the last European monitor lizards and is clearly not referable to the extant Varanus griseus or Varanus niloticus, the only species that could be taken into consideration on a present-day geographic basis. However, these fossils could represent a survivor of the monitor lizards of Asian origin that inhabited Europe during the Neogene.

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