Academic literature on the topic 'Testudinidae. Ecology'

We present a phylogenetic and divergence time analysis of the Chelonoidis chilensis complex (the southernmost tortoises of South America) within crown Testudinidae. We compiled a dataset of 1118 bp cytochrome b (cyt b) sequences derived from 111 individuals sampled across the known geographic range of the species, and performed a phylogenetic analysis employing Maximum Parsimony, Maximum Likelihood and Bayesian Inference methods. The resulting trees showed similar topologies and support values. The C. chilensis complex was always recovered as a monophyletic group composed by two major clades (i.e. haplogroups). The biogeographic distribution of one of these clades overlaps with the Dry Chaco eco–region, while the biogeographic distribution of the other overlaps with the Monte eco–region. In order to date the origin and diversification time of these two clades, we employed a previously published two-step molecular clock method. In the first step we dated the time of origin of C. chilensis as a clade within the Testudinidae family using new and previously published sequences, extinct testudinid taxa for age calibration and the Fossilized Birth-Death (FBD) model. In the second step we dated the divergence between the haplogroups of C. chilensis based on the time of origin estimated in the first step and a coalescent evolution model. Our results suggest that divergence between Dry Chaco and Monte tortoises may have occurred about 2.47 million of years ago. We interpret these results in the light of the environmental and geological changes that occurred during the late Pliocene to Middle Pleistocene of South America.

We describe new material, including juvenile specimens, of Hadrianus corsoni, Hadrianus majusculus, Echmatemys haydeni, and Echmatemys naomi. Testudinidae evolved in North America from one of the geoemydid-like forms in the genus Echmatemys, which have their lowest stratigraphic occurrence in the earliest Wasatchian North American land mammal “age” (early Eocene, Ypresian).

The phylogenetic relationships of 23 oxyurid species from five genera (21 parasite species of the Palaearctic Testudinidae, 1 parasite species of Uromastix acanthinurus Bell, 1825 from Algeria, and 1 parasite species of Cteno sa ura pectinata (Wiegmann, 1834) from Mexico) were investigated using 30 morphological characters obtained from species descriptions. The nonweighted analysis produced one shortest tree. All species of the ingroup form a monophyletic group and the oxyurid species of Testudinidae form a monophyletic group. The type species of the genus Alaeuris Thapar, 1925 is the basal member of the species parasitizing Testudinidae. The analysis confirms the monophyly of the genus Thaparia Ortlepp, 1933, whereas the genera Mehdiella Seurat, 1918 and Tachygonetria Wedl, 1862 are considered paraphyletic groups. The large diversification in the genus Tachygonetria is linked to their position in the host caecum. The ancestral state is in the paramucous and the derived state is in the centre of the caecum. This suggests that recent speciation in the group occurs in the centre of the caecum.

This study represents the first report on the amphibians and reptiles of Mount Korbu, the highest peak in the Titiwangsa Range (2182 m a.s.l.) and the second highest peak in Peninsular Malaysia. The Titiwangsa Range is the longest and most contiguous mountain range in Peninsular Malaysia, but only three upland localities have been extensively sampled and published on, indicating the urgent need for fieldwork to new localities along this range. We documented 18 species of amphibians from the families Bufonidae, Dicroglossidae, Megophryidae, Microhylidae, Ranidae, and Rhacophoridae and 16 species of reptiles from the families Agamidae, Gekkonidae, Scincidae, Colubridae, Pareidae, Viperidae, Testudinidae, and Trionychidae. This study also records significant range extensions for four species and provides the first collated checklist on the herpetofauna of the Titiwangsa Range.

Due to the critical status of Psammobates geometricus and the vulnerability of their habitat, there is a need to allocate areas for their protection. The aim of this study was to provide information on the space requirements and activity level of geometric tortoises to facilitate future conservation efforts.

Thesis (MSc)--Stellenbosch University, 2003.
ENGLISH ABSTRACT: The geometric tortoise, Psammobates geometricus, found in the Western Cape, South Africa, is one of the world's rarest tortoises. At present, it is only known from five isolated geographical areas, one being the Worcester-Tulbagh Valley. The primary aims of my study were to determine the status of geometric tortoise subpopulations along the Nl highway in the Worcester Valley, to determine the population structure of these subpopulations and, if necessary, to provide recommendations for the mitigation ofNI highway-induced impacts on geometric tortoise subpopulations along the road. All Renosterveld remnants along the Nl between Du Toitskloof and Worcester were surveyed for the presence of geometric tortoises, and tortoise density and population structure were determined for each remnant that supports tortoises. Two geometric tortoise subpopulations on opposite sides of the Nl were identified. In the larger remnant of the two, females dominated both the subadult and adult classes, whereas in the other remnant male frequency was slightly higher than female frequency for the adult class only. In both remnants, adult females were significantly larger than adult males in mean carapace length. Mean body mass for adult females and males also differed significantly in both remnants. Analysis of habitat quality showed that both remnants supporting the geometric tortoise are seriously infested by encroaching indigenous and alien plants. The barrier effect of the Nl highway can be mitigated by constructing underpasses, linking the two remnants on opposite sides of the road. Furthermore, road mortality of tortoises can be avoided by erecting tortoise proof fencing along appropriate sections of the highway in the Worcester Valley. By linking the remnants, the largest single area available to the geometric tortoise in the Worcester Valley will also be formed. An additional aim of my study was to investigate the correspondence of geometric tortoise density in individual habitat remnants to the West-to-East change in vegetation composition/characteristics occurring along the Nl in the Worcester Valley. Vegetation composition/characteristics were thus determined in all remnants also surveyed for tortoises. The West-to-East change in vegetation composition/characteristics of the study area indicates that there is a transition from Renosterveld in the West to karroid veld in the East.
AFRIKAANSE OPSOMMING: Die geometriese skilpad, Psammobates geometrieus, wat in die Wes-Kaap, Suid- Afrika, voorkom, is een van die wêreld se skaarste skilpaaie. Vandag word hierdie skilpad net nog in vyf geïsoleerde geografiese streke gekry, een van hulle die Worcester-Tulbagh Vallei. Die primêre doel van my studie was om die status van geometriese skilpad subpopulasies langs die Nl snelweg in die Worcester Vallei te ondersoek en om die populasiestruktuur van hierdie subpopulasies te bepaal. Verder was die doelook, om aanbevelings te maak oor hoe die impakte van die pad op die geometriese skilpad subpopulasies langs die Nl verminder kan word. Al die Renosterveld oorblyfsels langs die Nl tussen Du Toitskloof en Worcester, en binne die bekende gebied van die geometriese skilpad, is deursoek vir geometriese skilpaaie. Populasiedigtheid en populasiestruktuur van die skilpaaie is bepaal vir elke oorblyfsel wat skilpaaie bevat. Twee geometriese skilpad subpopulasies is gekryaan teenoorgestelde kante van die Nl. In die groter oorblyfsel, het wyfies albei die onvolwasse en volwasse klasse gedomineer. In die ander oorblyfsel is gevind dat die frekwensie van mannetjies ietwat hoër was as die frekwensie van wyfies, maar vir slegs die volwasse kategorie. Binne albei oorblyfsels is gevind dat volwassse wyfies betekenisvol groter in gemiddelde doplengte is as volwasse mannetjies. Gemiddelde liggaamsgewig het ook betekenisvol verskil tussen volwasse wyfies en mannetjies in albei oorblyfsels. 'n Analise van habitatkwaliteit het gewys dat beide oorblyfsels wat die geometriese skilpad ondersteun grootliks ingeneem is deur inheemse indringers, sowel as uitheemse plante. Die versperrings effek van die Nl snelweg kan verminder word deur duikwege te skep wat die twee ooblyfsels, op teenoorgestelde kante van die pad, verbind. Bowendien, deur 'n ondeurdringbare heining langs passende dele van die snelweg in die Worcester Vallei op te rig, sal skilpadmortaliteit vermy word. Deur oorblyfsels te verbind, salook die grootste enkele area, beskibaar aan die geometriese skilpad in die Worcester Vallei, gevorm word. 'n Addisionele doel van hierdie studie was om veranderinge in vegetasie langs 'n wes-na-oos gradient binne die studie area te korreleer met die teenwoordigheid van skilpaaie langs hierdie gradient. Vegetasie samestelling/eienskappe is dus bepaal vir elke oorblyfsel wat deursoek is vir skilpaaie. Die wes-na-oos verandering in vegetasie samestelling/eienskappe binne die studie area wys dat daar 'n oorgang van Renosterveld in die weste na 'n karooagtige veld in die ooste is.

Tesina (Grado en Ciencias Biológicas)--Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Lugar de Trabajo: Centro de Zoología Aplicada. Facultad de Ciencias Exactas, Físicas y Naturales. Universidad Nacional de Córdoba. 2019. 38 h. tabls.; ils.; maps.; grafs. Contiene Referencia Bibliográfica.
La tortuga terrestre (Chelonoidis chilensis) continúa siendo en Argentina objeto del mercado ilegal, a pesar de la legislación vigente que la protege. Asimismo, en gran parte de su área de distribución el avance de la frontera agrícola desencadenó un severo proceso de deforestación que podría atentar con la viabilidad de sus poblaciones. Diversas acciones de manejo son utilizadas para maximizar la producción ganadera en los áridos suelos del Chaco, como aquellas tendientes a reducir el estrato arbustivo e incrementar la productividad de forraje herbáceo. Específicamente para la Tortuga terrestre (C.chilensis), habitante del Chaco, no hay estudios que evalúen el impacto de estas acciones antrópicas sobre sus poblaciones como tampoco estudios poblacionales que puedan ser utilizados como líneas de base para el monitoreo de sus poblaciones. En el Campo Experimental F. Cantos del INTA en Santiago el Estero, se está llevando a cabo una acción de manejo forestal, llamada Rolado de Baja Intensidad (RBI), con el objetivo de generar bosques abiertos, a través del aplastamiento de la vegetación de sotobosque y la permanencia de los árboles de gran porte, para efectuar luego siembra de pasturas para el ganado. En este trabajo se propuso evaluar asociaciones entre la presencia y abundancia de la Tortuga terrestre (C.chilensis) y las características ambientales resultantes de manejo con RBI, y por el otro caracterizar una población de esta especie, en términos de sus dimensiones, proporción de sexos y abundancia relativa en un área del bosque en buen estado de conservación. Se efectuaron muestreos de sus poblaciones en dos campañas realizadas durante el mes de noviembre de 2016 y 2017, teniendo en cuenta un gradiente de disturbio que incluyó un área bien conservada con prácticamente nula actividad antropogénica durante los últimos 20 años y un sector donde se implementó de manera reciente RBI. Se establecieron 12 parcelas en total, 6 en la zona con RBI y 6 en la zona sin RBI. Dentro de cada parcela se establecieron 6 transectas distribuidas aleatoriamente en línea recta de 200 m de largo y se recorrieron considerando un ancho de faja de 10 metros. En cada transecta se tomaron datos de vegetación y se advirtió mediante observación directa la presencia-ausencia de tortugas. Se utilizaron modelos lineales generalizados mixtos (GLMM) para evaluar los posibles efectos de las variables ambientales sobre la presencia-ausencia de la especie, seleccionando al mejor modelo según el criterio de información de Akaike. Se capturaron 29 tortugas y se hallaron 17 caparazones, estos últimos en una mayor proporción en transectas correspondientes a parcelas con RBI, lo cual permitió adjudicar un importante efecto del rolado sobre la abundancia de la especie a lo largo del gradiente de disturbio; por otro lado se caracterizó la población en términos de dimensiones corporales, peso, proporción de sexos y se calculó el índice de condición corporal (ICC) para cada individuo de la población. En relación a esto se detectó un mayor ICC en proporción con individuos mantenidos en cautiverio. La abundancia de la especie en el área alcanza los niveles más altos registrados hasta ahora en el país (1,38 tortugas/hectárea). El RBI genera un importante efecto en la abundancia de las poblaciones de C.chilensis, es por ello que se recomiendan acciones de manejo para que su efecto no afecte a la especie.