Comparative morphology of Liolaemus lizards precloacal glands

Liolaemid lizards and amphisbaenids have precloacal pores in the anterior border of the cloaca, where epidermal glands drain and expel pheromonal secretions. Precloacal glands occur usually only in males, but in those few species where both sexes have precloacal glands, these are larger in males. Only the morphology and/or histology of precloacal glands of amphisbaenids have been described, and it is unknown whether in lizards these glands differ across ages, sexes and/or species, and if the lack of pores is associated with a lack of glands. We investigated for the first time the morphology and histology of lizard precloacal glands, by studying three Liolaemus species that differ in the presence of pores in their cloaca: L. irregularis, in which adults and juveniles of both sexes have pores; L. poecilochromus, in which only adult males have pores, and L. neuquensis, in which the adults of both sexes lack pores. Results show that the number of pores varies among species and sexes, but not between ages of a species. Adults, but not juveniles, of L. irregularis have sexual dimorphism in pore sizes; these are larger in males than in females. In addition, pores are larger in adult males of L. irregularis than in L. poecilochromus. Glands are tubuloalveolar with holocrine secretion, having similar structure across individuals, although adult males have larger glands than females and juveniles. Finally, the structure of Liolaemus precloacal glands is very similar to those of the amphisbaenid precloacal glands and the femoral glands of other lizard species

Protrusión ocular en lagartos Liolaemus (Weigmann 1843)

t is described for the first time the eye-bulging display in two liolaemid lizards, Liolaemus chiliensis and L. gravenhorstii. This display occurs in very low frequency and it was observed in captivity. It is discussed the possibility that the thermoregulation and/or eye-cleaning hypotheses may explain the occurrence of this display in these two species.En este trabajo se describe por primera vez el despliegue de protrusión ocular en dos lagartos Liolaemidos, Liolaemus chiliensis y L. gravenhorstii. El despliegue ocurre en muy baja frecuencia y fue observado en cautiverio. Se discute la posibilidad de que las hipótesis de termorregulación y/o de limpieza de ojos puedan explicar la ocurrencia de este despliegue en estas dos especies

Retreat Sites Shared by Two Liolaemus Lizard Species: Exploring the Potential Role of Scents

Some lizard species modulate the use of a retreat site based on the presence of scents from other individuals, behavior that requires scent recognition. Here, we investigated if two congeneric and syntopic lizards (adults of Liolaemus coeruleus and juveniles of L. ceii, which can be found sharing retreat sites in the wild) discriminate scents from each other during the pre-hibernation period. If the presence of heterospecific scents modulates sharing retreat sites, species would discriminate each other’s scents. Lizards were individually exposed to four treatments, which were enclosures with scents of (1) from the focal individual (own); (2) a conspecific of the same sex as the focal lizard; (3) a heterospecific of the same sex as the focal lizard; and (4) a control (i.e., enclosure with a clean substrate). Our results suggest that there is no heterospecific recognition. This finding was not due to an inability to chemo-assess scents, since both species exhibited self-recognition (recognition of their own scents) and juveniles of L. ceii also showed conspecific recognition. Although it might be advantageous for species to share retreat sites, chemical recognition of heterospecific scents does not modulate this behavior in these syntopic species.Algunas especies de lagartos modulan el uso de un sitio de retiro basados en la presencia de rastros de olores de otros individuos presentes en el sitio, comportamiento que requiere reconocimiento de estos rastros de olores. En este trabajo, investigamos dos lagartos cogenéricos y sintópicos (adultos de Liolaemus coeruleus y juveniles de L. ceii, los cuales pueden ser encontrados en la naturaleza compartiendo sitios de retiro), si discriminan los rastros de olores de cada uno de ellos durante el periodo pre-invernal. Si la presencia de rastros de olores heteroespecíficos modula el compartir sitios de retiro, ambas especies discriminarían los rastros de olores entre sí. Los lagartos fueron expuestos individualmente a cuatro tratamientos, los cuales fueron los recintos con diferentes olores de: (1) propio, del individuo focal; (2) conespecífico del mismo sexo que el lagarto focal; (3) heteroespecífico del mismo sexo que el focal y (4) control, i.e., un recinto con substrato limpio. Nuestros resultados sugieren que no habría presencia de reconocimiento químico heteroespecífico, lo cual, no es consecuencia de una incapacidad para evaluar rastros químicos, puesto que ambas especies exhibieron auto reconocimiento (reconocimiento de sus rastros de olores propios) y los juveniles de L. ceii además exhibieron reconocimiento de sus conespecíficos. A pesar de que estas especies puedan beneficiarse de compartir sitios de refugio, aparentemente, el reconocimiento químico de los rastros de heterospecíficos, no modularía el sitio de refugio compartido por estas especies sintópicas.Fil: Ruiz Monachesi, Mario Ricardo. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Valdecantos, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Lobo Gaviola, Fernando Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Cruz, Felix Benjamin. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Norte. Instituto de Investigaciones En Biodiversidad y Medioambiente. Subsede San Martín de Los Andes-inibioma | Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Instituto de Investigaciones En Biodiversidad y Medioambiente. Subsede San Martín de Los Andes-inibioma.; ArgentinaFil: Labra, Antonieta. University of Oslo; Norueg

Chemical self-recognition in the lizard Liolaemus fitzgeraldi

Abstract Social-chemical recognition is exhibited by all the Liolaemus lizards tested to date, except Liolaemus fitzgeraldi, which during post-hibernation did not discriminate chemosignals of same-sex individuals from a control. To clarify if L. fitzgeraldi is unique among the studied Liolaemus in lacking social-chemical recognition or if this was previously undetected, we recorded behavior during pre-and post-hibernation when confronted with chemosignals of conspecifics and from themselves. L fitzgeraldi showed self-recognition and seasonal changes in two exploratory behaviors. Potentially, conspecific recognition in L fitzgeraldi was undetected due to seasonality, but this species may rely comparatively less on chemical communication than congeners

Determination of susceptibility to sensitization to dental materials in atopic and non-atopic patients

Introduction: Some studies report that atopic patients have a greater frequency of delayed-type sensitization than non-atopic patients. Objective: To determine the influence of the atopic condition on delayed sensitization to dental materials. Design: cross-sectional study. Methods: Forty (40) atopic subjects and forty (40) non-atopic subjects, of both sexes, between 20 and 65 years of age were included. The determination of delayed sensitization to dental materials was performed using patch test. An oral exam was also carried out to check for lesions of the oral mucosa. Results: 61.25% of the patients were positive for delayed-type sensitization to one or more allergens, being palladium chloride (21.25%), ammoniated mercury (20%), benzoyl peroxide (12.5%) and amalgam (10%) the most frequent. The frequency of sensitization was 67.5% in the group of atopic patients, compared to 55% in the non atopic group (p>0.05). The materials with the greatest difference of sensitization in atopic compared to non-atopic patients were ammoniated mercury, benzoyl peroxide, amalgam and Bisphenol A Dimethacrylate (BIS-GMA). Conclusion: The atopic condition is not related to a higher frequency of delayed sensitization to a battery of dental materials. © Medicina Oral

Without a body of evidence and peer review, taxonomic changes in Liolaemidae and Tropiduridae (Squamata) must be rejected

In his recent self-published book "Reptiles en Chile", Diego Demangel Miranda presented 13 taxonomic changes for liolaemid and tropidurid lizards. While these could be considered validly published according to the International Code of Zoological Nomenclature, we show that these taxonomic propositions lack the necessary scientific rigor in terms of replicability, specimen work, lack of peer review and that they do not follow best practices accepted by the herpetological community. Therefore, we hereby invalidate all 13 taxonomic changes proposed in this book, leaving the taxonomy unaffected. Finally, we call attention to the potentially negative consequences of using these taxonomic changes in conservation and environmental impact studies as incorrect decisions might be taken in relation to the species involved

The peculiar case of an insectivorous iguanid lizard that detects chemical cues from prey

Ecological and phylogenetic factors determine which sensory modalities organisms use in their day-to-day activities. Among lizards, empirical studies indicate a tight association between foraging strategies and the ability to detect chemical cues from prey. Consequently, ambush insectivores do not detect food chemicals and these differences have a phylogenetic basis, as ambush lizards mainly belong to the Iguania clade. These data contrast, however, with the widespread uses of chemoreception in the Iguania genus Liolaemus, which are mostly insectivorous ambush predators. Moreover, observations from different Liolaemus species suggest a capability to find prey through chemoreception. In order to clarify the abilities of Liolaemus to detect chemical cues from prey, the chemoreceptive behavior of the insectivorous ambush predator, L. lemniscatus, was studied. Lizards were given the choice between areas with and without chemical cues from a food item (mealworms). Results show that test an

The relation between hairpin formation by mitochondrial WANCY tRNAs and the occurrence of the light strand replication origin in Lepidosauria

Mitochondrial light strand DNA replication is initiated at light strand replication origins (OLs), short stem-loop hairpins formed by the heavy strand DNA. OL-like secondary structures are also formed by heavy strand DNA templating for the five tRNAs adjacent to OLs, the WANCY tRNA cluster. We tested whether natural OL absence associates with greater capacities for formation of OL-like structures by WANCY tRNA genes. Using lepidosaurian taxa (Sphenodon, lizards and amphisbaenids), we compared WANCY tRNA capacities to form OL-like structures between 248 taxa possessing an OL with 131 taxa without OL (from different families). On average, WANCY tRNA genes form more OL-like structures in the absence of a regular OL than in its presence. Formation of OL-like structures by WANCY tRNAs follows hierarchical patterns that may reduce competition between the tRNA's translational function and its secondary OL function: the rarer the tRNA's cognate amino acid, the greater the capacity to form OL-

Emisión de sonidos en lagartos nativos de Chile: el estado del arte

Los lagartos dependen principalmente de señales químicas y visuales para comunicarse y, en menor medida, de señales acústicas, por lo que en general se ha considerado que estos reptiles no emiten sonidos. Sin embargo, representantes de diferentes familias de lagartos pueden producir sonidos a través de la boca y en distintos contextos. En Chile, los reportes sobre emisión de sonidos en lagartos son escasos y anecdóticos, por lo que en pocos casos estas señales acústicas han sido estudiadas en detalle. Pese a ello, el conocimiento sobre la emisión de sonidos de algunas especies nativas ha aumentado durante los últimos años. El objetivo de la presente revisión es analizar el estado del arte sobre la emisión de sonidos en lagartos nativos de Chile y conjuntamente, incentivar el desarrollo de investigación relativa a este particular modo de comunicación. Para ello, realizamos una recopilación exhaustiva de la información existente sobre este tópico. De las 121 especies de lagartos nativos de Chile, tan solo se ha reportado emisión de sonidos en 13 especies (10.7%), pertenecientes a los géneros Diplolaemus, Garthia, Lepidodactylus, Liolaemus, Phyllodactylus, Phymaturus y Pristidactylus. La mayor parte de estas especies emite sonidos en contextos de depredación, probablemente con la finalidad de disuadir el ataque de un depredador. Discutimos diversos aspectos a considerar en futuras investigaciones sobre emisión de sonidos en lagartos. Lizards mainly depend on chemical and visual signals to communicate and, to a lesser extent, on acoustic signals, so generally it has been considered that these reptiles do not emit sounds. However, representatives of different lizard families can emit sounds through their mouths and in different contexts. In Chile, the reports on the emission of sounds in lizards are scarce and anecdotal, and in very few cases, these acoustic signals have been studied in detail. However, the knowledge about sound emissions of some species of native lizards from Chile has increased during the last few years. The goal of this review is to define the state of the art on the emission of sounds in native lizards of Chile as well as to encourage the development of research related to this particular communication modality. For this, we made an exhaustive compilation of the existing information on this topic. Of the 121 species of native lizards in Chile, there are reports of sound emission for only 13 species (10.7%) of the genus Diplolaemus, Garthia, Lepidodactylus, Liolaemus, Phyllodactylus, Phymaturus and Pristidactylus. Most of these species emit sounds in predation contexts, probably for the purpose of deterring the attack of a predator. We discuss several aspects that should be considered for the future studies about lizard sounds