Iguanas

INTRODUCCIÓN: La Iguana negra es una especie endémica de México, su distribución es bastante amplia, encontrándose desde Sinaloa hasta Chiapas, también en los estados de Durango, Nayarit, Jalisco, Colima, Michoacán, Morelos Guerrero, Puebla, Oaxaca y Zacatecas (1,2). Es una iguana de talla grande, larga y robusta, con párpados móviles y cola larga con púas características; la cabeza es larga y aplanada, el color del cuerpo es uniforme negro con manchas dispersas de color blanco-amarillentas, además de que la cabeza siempre es de color negra. (3) En algunas regiones de México, la iguana negra ha sido considerada una fuente de alimento desde mucho tiempo atrás (1), tan atrás que se han encontrado restos arqueológicos que muestran que la cultura maya utilizaba a la iguana negra como fuente de alimento (4). Actualmente es utilizada como fuente de proteína, principalmente en regiones rurales del país, no obstante no solo la carne es aprovechada sino que también los huevos y la piel son utilizados para su comercialización en diversas actividades (1,5); sin embargo este aprovechamiento excesivo, la utilización de su hábitat para suelos ganaderos o para la construcción de vías para uso humano, las falsas creencias en diversos poblados y también la venta y comercialización ilegal ha llevado a que las poblaciones en vida silvestre se vean en declive (5,6). En México la demanda anual es de 12,500 ejemplares, en donde los criaderos registrados son capaces de abastecer 2,500 ejemplares anualmente (6), lo que lleva a centrar miras a este ejemplar, principalmente para poder abastecer esas necesidades que el país requiere y para poder evitar que la población siga en declive, además de que desarrollar sistemas de crianza en unas

Guide to Lizards is an essential directory to more than 300 lizard species, including readily available terrarium choices plus dozens of seldom seen and rare species that are of great interest to hobbyists and travelers alike. Written by an acknowledged expert on lizards, each profile contains information on size, range, habitat, natural history, care, and suitability as a pet. Profiles are color-coded and organized by native region and feature discussion of how to find lizards in their habitat, making this an excellent book for outdoor-loving hobbyists and ecotourists. Full-color photos of species, subspecies, and color variants are complimented by informative sidebars.

Iguaninae is a monophyletic taxon of tetrapodous squamates (lizards) that can be distinguished from other iguanians by at least five synapomorphies. Skeletal variation within Iguaninae is described and forms the basis of systematic characters used to determine phylogenetic relationships among eight basic taxa, the currency recognized iguanine genera. Evolutionary character polarities are determined by comparison with four closely related taxa, basiliscines, crotaphytines, morunasaurs, and oplurines.
    The distributions of derived characters among iguanine taxa suggest that: (1) Either Brachylophus or Dipsosaurus is the sister group of the remaining iguanines (Iguanini). (2) Dipsosaurus is a monophyletic taxon diagnosed by at least six synapomorphies. (3) Brachylophus is a monophyletic taxon diagnosed by at least eight synapomorphies. (4) Iguanini, containing Amblyrhynchus, Conolophus, Ctenosaura, Cyclura, Iguana, and Sauromalus, is a new monophyletic taxon diagnosed by at least three synapomorphies. (5) Within Iguanini, the relationships among four taxa--Ctenosaura, Sauromalus, Amblyrhynchina, and Iguanina--are unresolved. (6) Ctenosaura is a monophyletic taxon diagnosed by at least three synapomorphies. (7) Enyaliosaurus is monophyletic, but it is a subgroup of Ctenosaura rather than a separate taxon. If Enyaliosaurus is separated from Ctenosaura, then Ctenosaura is not monophyletic. (8) Sauromalus is a monophyletic taxon diagnosed by at least 24 synapomorphies, many of which are convergent in  Amblyrhynchus. (9) Amblyrhynchina is a new monophyletic taxon containing the Galapagos iguanas Amblyrhynchus and Conolophus, and is diagnosed by at least 11 synapomorphies. (10) Amblyrhynchus is a monophyletic taxon diagnosed by at least 28 synapomorphies and is perhaps the most divergent iguanine from the most recent common ancestor of all of them. Many of the unique features of Amblyrhynchus appear to be related to its unique natural history. (11) Conolophus is a monophyletic taxon diagnosed by at least eight synapomorphies and cannot, therefore, be considered ancestral to Amblyrhynchus. (12) Iguanina is a new monophyletic taxon composed oi Iguana and Cyclura and is diagnosed by at least three synapomorphies. (13) Iguana is a monophyletic taxon diagnosed by at least seven synapomorphies. (14) Monophyly of Cyclura is a problem in need of further study. Although three ostensible synapomorphies support monophyly of Cyclura, other derived characters suggest that some Cyclura shared a more recent common ancestor with Iguana than with other Cyclura.
    Summaries of Iguaninae and its monophyletic subgroups down to the level of the eight basic taxa are provided; each summary includes the type of the taxon, etymology of the taxon name, a phylogenetic definition, geographic distribution, a list of diagnostic synapomorphies, the fossil record, and various comments.

The Paris Natural History Museum herpetological collection (MNHN-RA) has seven historical specimens of Brachylophus spp. collected late in the 18<sup>th</sup> and early in the 19th centuries. Brachylophus fasciatus was described in 1800 by Brongniart but its type was subsequently considered as lost and never present in MNHN-RA collections. We found that 220 year old holotype among existing collections, registered without any data, and we show that it was donated to MNHN-RA from Brongniart's private collection after his death in 1847. It was registered in the catalogue of 1851 but without any data or reference to its type status. According to the coloration (uncommon midbody saddle-like dorsal banding pattern) and morphometric data given in its original description and in the subsequent examination of the type in 1802 by Daudin and in 1805 by Brongniart we found that lost holotype in the collections. Another MNHN-RA specimen has Horn Islands (Wallis and Futuna) as the...

The generally accepted framework for the evolution of a key feature of the avian respiratory system, unidirectional airflow, is that it is an adaptation for efficiency of gas exchange and expanded aerobic capacities, and therefore it has historically been viewed as important to the ability of birds to fly and to maintain an endothermic metabolism. This pattern of flow has been presumed to arise from specific features of the respiratory system, such as an enclosed intrapulmonary bronchus and parabronchi. Here we show unidirectional airflow in the green iguana, a lizard with a strikingly different natural history from that of birds and lacking these anatomical features. This discovery indicates a paradigm shift is needed. The selective drivers of the trait, its date of origin, and the fundamental aerodynamic mechanisms by which unidirectional flow arises must be reassessed to be congruent with the natural history of this lineage. Unidirectional flow may serve functions other than expa...

"Originally published in 1992, Giant Lizards is a bestselling reference held in high regard within every level of the herpetological community for its authoritative and thorough coverage of lizard biology.

Now in a completely revised and expanded volume, Giant Lizards features all newly written information by an expert on monitors and other large lizards (defined as those reaching over 3 feet in length) and it covers over 90 species. Lizard profiles range from the relatively affordable to the extremely expensive, and from those commonly kept as pets to those critically endangered and unobtainable. Species include iguanas (including green iguanas), rock iguanas, Galapagos Island iguanas, tegus, sail-fin lizards, Gila monsters, beaded lizards, water dragons, monitors (including savannah, water, and Nile monitors plus Komodo dragons), and more."

The effects of the direct interaction between hybridization and speciation-two major contrasting evolutionary processes-are poorly understood. We present here the evolutionary history of the Galápagos marine iguana (Amblyrhynchus cristatus) and reveal a case of incipient within-island speciation, which is paralleled by between-island hybridization. In-depth genome-wide analyses suggest that Amblyrhynchus diverged from its sister group, the Galápagos land iguanas, around 4.5 million years ago (Ma), but divergence among extant populations is exceedingly young (less than 50 000 years). Despite Amblyrhynchus appearing as a single long-branch species phylogenetically, we find strong population structure between islands, and one case of incipient speciation of sister lineages within the same island-ostensibly initiated by volcanic events. Hybridization between both lineages is exceedingly rare, yet frequent hybridization with migrants from nearby islands is evident. The contemporary snaps...

The histological and physiological effects of the removal of superficial corneous epidermal materials have been studied in several squamate species and a caiman. The gross and microscopic anatomy of the squamate integument has characteristics which make cellophane stripping inherently variable, but in general, when corneous materials were removed, they are replaced over a period of one to two weeks, by a tissue with the histological characteristics of the normal alpha-layer. This tissue may be produced by stimulated germinal activity and/or metaplasia of the other presumptive cell populations. In caiman, the thickness of the corneous tissues of the outer scale surface is reduced by stripping and the tissue is restored to normal in approximately two weeks by stimulated germinal proliferation. Measurements of cutaneous water loss (CWL) before, immediately after, and during two weeks post-trauma revealed the following. There is a sudden rise in CWL immediately after stripping, and valu...

A two-phase cross-over therapeutic study was performed with 19 green iguanas (Iguana iguana) maintained within a preferred optimum temperature range of 26 to 37 degrees C. During phase 1, they were fed a normal vegetarian diet and medicated orally with either allopurinol or a placebo control once a day for seven days. Uric acid concentrations, total protein, packed-cell volumes (pcv) and bodyweights were recorded from each lizard before and after treatment to determine the effects of allopurinol. In phase 2, after a 10-day washout period, the iguanas were fed a high protein diet to induce hyperuricaemia. Normo- and hyperuricaemic iguanas that received 24.2 (3.2) mg/kg allopurinol had significantly lower mean (sd) uric acid concentrations (100.3 [53.1] micromol/l) than the controls (159.3 [100.3] micromol/l). There were no detectable interactions between the doses of allopurinol or placebo, and the iguanas' diet, weight, pcv or total protein. The allopurinol was well tolerated, a...