Sonntag, 03 Dezember 2017 15:45

WAGNER, P. & DITTMANN, A. (2014)

Medicinal use of Gekko gecko (Squamata: Gekkonidae) has an impact on agamid lizards

SALAMANDRA 50(3): 185–186 30. Oktober 2014. ISSN 0036–3375.

Volltext (PDF)

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Freitag, 04 August 2017 14:34

GRISMER, L. L. et al. (2012)

GRISMER, L. LEE,  PERRY L. WOOD, JR., EVAN S. H. QUAH, SHAHRUL ANUAR, MOHD. ABDUL MUIN, MONTRI SUMONTHA, NORHAYATI AHMAD, AARON M. BAUER, SANSAREEYA WANGKULANGKUL, JESSE L. GRISMER & OLIVIER S. G. PAUWELS (2012).

A phylogeny and taxonomy of the Thai-Malay Peninsula Bent-toed Geckos of the Cyrtodactylus pulchellus complex (Squamata: Gekkonidae): combined morphological and molecular analyses with descriptions of seven new species.

Zootaxa 3520: 1–55.

Abstract:

An integrative taxonomic analysis using color pattern, morphology and 1497 base pairs of the ND2 itochondrial gene and its five flanking tRNAs demonstrated that nine monophyletic species-level lineages occur within the Cyrtodactylus pulchellus complex (Cyrtodactylus pulchellus sensu strictu and C. macrotuberculatus) of the Thai-Malay Peninsula that have a sequence divergence between them ranging from 5.9–16.8%. Additionally, each lineage is discretely diagnosable from one another based on morphology and color pattern and most occur in specific geographic regions (upland areas or islands) that prevent or greatly restrict interpopulation gene  flow. Six of these lineages were masquerading under the nomen C. pulchellus and are described as the following: Cyrtodactylus astrum sp. nov. from  northwestern  Peninsular Malaysia and southwestern Thailand; C. langkawiensis sp. nov., at this point endemic to Langkawi Island, Malaysia; C. bintangrendah sp. nov., a lowland  species  surrounding  the  Banjaran  (=mountain  range)  Bintang  of  northwestern Peninsular Malaysia; C. bintangtinggi sp. nov., endemic to the upland regions of the Banjaran Bintang of northwestern Peninsular Malaysia; C. trilatofasciatus sp. nov., endemic to upland regions of Cameron Highlands in the central portion of the Banjaran Titiwangsa in Peninsular Malaysia; and C. stralotitiwangsaensis sp. nov. from the more southerly upland regions of the Banjaran Titiwangsa. An additional species, Cyrtodactylus lekaguli sp. nov. from Satun, Trang, Surat Thani, and Phang-nga provinces in southern Thailand, was identified on the basis of morphology and color pattern and is hypothesized to be part of a clade containing C. astrum sp. nov. and C. langkawiensis sp. nov.

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Samstag, 15 Juli 2017 09:56

CAMPOS SOARES de VASCONCELOS, R. (2010)

Integrative Approaches to the Systematics and Conservation of the Reptiles of the Cape Verde Islands.

PhD Thesis. Departamento de Biologia Faculdade de Ciências da Universidade do Porto

Volltext: http://www.scvz.org/pdf/TeseRVLowRes_ii.pdf

Summary:

Two of the main sensitivities of Conservation Biogeography are the inadequacies in taxonomic and chorological data, the so-called Linnean and Wallacean shortfalls, respectively. These shortfalls increase in the more remote areas such as oceanic islands. This thesis contributed to dilute those shortfalls in one of those remote areas, the Cape Verde Islands, for one of its least studied group, the reptiles.The specific goals of this thesis were related to answering to what diversity occurs there and to address putative biogeographic factors that explain why diversity is unevenly distributed. Then, it is aimed to answer where this biodiversity can be found and, based on all the gathered data, to plan how to better protect it at different levels.

First, the phylogeographic patterns of terrestrial reptiles were studied to identify an introduced agamid and cryptic endemic taxa of the three genera (Hemidactylus, Tarentola and Chioninia) and to clarify their systematics. The new introduced taxon in Cape Verde was identified as Agama agama. Also, some endemic subspecies were upgraded to the specific status and three new cryptic species (Hemidactylus lopezjuradoi, Tarentola bocageiand T. fogoensis) and subspecies (Chioninia vaillanti xanthotis, C. spinalis boavistensis and C. s. santiagoensis) were described using an integrative approach combining morphological, genetic and population analyses. These studies highlighted the usefulness of integrative datasets in the fields of Taxonomy and Phylogeography and how they can improve the performance of taxa estimations. In addition, the origin of the introduced Agama and the colonisation patterns of the endemic taxa were inferred and several historical and environmental factors, such as the Pleistocene sea-level falls and altitude, were related with the uneven distribution of diversity at intraspecific level. Low intraspecific divergence between reptile lineages of the same island has been explained by the recent volcanic activity and high ecological stress that could lead to population extinctions, and the low habitat diversity within some islands that could restrain opportunities for allopatric diversification.

Secondly, extensive sampling and bibliographic chorological data were compiled to produce and updated distribution atlas for all taxa addressing doubtful or erroneous records and to develop predictive maps of occurrence based on ecological niche-based models for most of the endemic taxa. This data also allowed the detection of the wide-spreading of the introduced H. angulatus in Santiago and Boavista and the colonisation of two new islands by the exotic H. mabouia. In addition, it allowed updating the conservation status for the endemic taxa showing that around half of them are threatened under the IUCN criteria and that the most frequent classifying criterion was related to restricted geographic range. The most pervasive threats identified are related to natural disasters, as droughts and volcanic activity, intrinsic factors, such as low population densities and restricted range, and introduced species.

Finally, this work also demonstrated how ecological niche-based models are useful tools to infer ranges on relatively under-sampled and remote areas with high accuracies and how they can be applied to conservation, maximizing efficiency of reserve designs. Results depicted that in Santa Luzia, Branco, Raso, Sal, Boavista, Maio and Rombos designation of new protected areas is not a priority since the ones that are going to be implemented will reach the conservation targets for all identified evolutionary significant units of those islands and islets. On the other hand, new or modified reserves should be implemented on the remaining islands to cover all identified lineages of Cape Verdean reptiles. This measure is especially important in Fogo and Brava, where no planning unit selected by the area prioritisation scenarios is within the protected areas limits and no protected area is planned, respectively.
Altogether, this work exemplifies the usefulness of integrating different disciplines to more effectively allowing systematic conservation planning of biodiversity.

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Donnerstag, 14 Juni 2018 14:41

RÖLL, B. & VON DÜRING, M. U. (2008)

Sexual characteristics and spermatogenesis in males of the parthenogenetic gecko Lepidodactylus lugubris (Reptilia, Gekkonidae).

Zoology (Jena) 111(5):385-400.
doi: 10.1016/j.zool.2007.09.004. Epub 2008 May 29.

Abstract:

Obligately parthenogenetic lizards usually are all-female populations of hybrids producing diploid oocytes by premeiotic endomitosis and quasi-normal meiosis. In an all-female strain of the gekkonid lizard Lepidodactylus lugubris several phenotypic males arose spontaneously. The sexual characteristics of these males were studied using light and electron microscopy and compared with normal males of the bisexual genus Lygodactylus. Emphasis was layed on morphology of seminiferous tubules, occurrence of spermatogenic stages and ultrastructure of spermatozoa. The phenotypic males possessed preanal pores filled with secretions and a sexual nephric segment which were exactly the same as in normal, reproductively active males. In the testes, density and morphology of non-spermatogenic cell types, the Leydig and Sertoli cells, indicate a normal production of testicular testosterone and a normal function of the blood-testis barrier, respectively. Both in the normal and the phenotypic males, all meiotic cell types of spermatogenesis can be recognised in the seminiferous tubules and are apparently identical, indicating a normal meiosis without impairment in the phenotypic males. In contrast, the differentiation process of spermatids is markedly disturbed in the phenotypic males of L. lugubris. In the normal male, spermiogenesis results in mature spermatids and spermatozoa with small elongated nuclei, an acrosomal complex, and a flagellar tail possessing one axoneme. Spermatozoa fill both the lumen of most seminiferous tubules and the lumina of ductus epididymidis and ductus deferens. In the phenotypic male, spermiogenesis results in seemingly normal spermatids and in spermatozoa with large, non-elongated, deformed nuclei and/or irregular tails possessing more than one axoneme. Both the lumen of most seminiferous tubules and the lumina of the ductus epididymidis and the ductus deferens contain relatively few spermatozoa. We suggest that the phenotypic males inherited the ability for a premeiotic endomitosis from their all-female ancestral lineage. While in females this leads to quasi-normal meiosis and diploid oocytes capable of development, the small nuclei of the spermatozoa are unable to contain a diploid set of chromosomes. Because of the high amount of deformed spermatozoa and possibly uncontrolled loss of genetic material in structurally normal, but aneuploid spermatozoa we conclude that these otherwise perfect males are infertile, thus constituting another example of gametic sterility.

 

röll-biblio

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Applications of Ecological Niche Modeling for Species Delimitation: A Review and Empirical Evaluation Using Day Geckos (Phelsuma) from Madagascar.

Systematic Biology 56 (6): 907 - 923. DOI: https://doi.org/10.1080/10635150701775111

Abstract:

Although the systematic utility of ecological niche modeling is generally well known (e.g., concerning the recognition and discovery of areas of endemism for biogeographic analyses), there has been little discussion of applications concerning species delimitation, and to date, no empirical evaluation has been conducted. However, ecological niche modeling can provide compelling evidence for allopatry between populations, and can also detect divergent ecological niches between candidate species. Here we present results for two taxonomically problematic groups of Phelsuma day geckos from Madagascar, where we integrate ecological niche modeling with mitochondrial DNA and morphological data to evaluate species limits. Despite relatively modest levels of genetic and morphological divergence, for both species groups we find divergent ecological niches between closely related species and parapatric ecological niche models. Niche models based on the new species limits provide a better fit to the known distribution than models based upon the combined (lumped) species limits. Based on these results, we elevate three subspecies of Phelsuma madagascariensis (P. m. madagascariensis, P. m. grandis, and P. m. kochi) to species rank and describe a new species of Phelsuma from the P. dubia species group. Our phylogeny continues to support a major endemic radiation of Phelsuma in Madagascar, with dispersals to Pemba Island and the Mascarene Islands. We conclude that ecological niche modeling offers great potential for species delimitation, especially for taxonomic groups exhibiting low vagility and localized endemism and for groups with more poorly known distributions. In particular, niche modeling should be especially sensitive for detecting recent parapatric speciation driven by ecological divergence, when the environmental gradients driving speciation are represented within the ecological niche models.

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Freitag, 15 Juni 2018 20:56

HENKEL, F. W. & SCHMIDT, W. (2003)

Geckos: Biologie - Haltung - Zucht.

176 Seiten, Farbfotos, Zeichnungen. 2. völlig neu bearbeitete Auflage.
Verlag Ulmer Stuttgart. ISBN 3-8001-3854-9

Verlagstext:

Das Buch behandelt die Gruppe der Geckos einschließlich der Flossenfüße.Die vorliegende zweite Auflage des erfolgreichen Werkes berücksichtigt dabei neueste Erkenntnisse über Systematik, Biologie und Verhalten der Tiere. Neben den schon längere Zeit bekannten Geckos wird eine Vielzahl von Arten vorgestellt, die in den letzten Jahren neu importiert und beschrieben wurden. Dabei liegt der Schwerpunkt auf den Geckos, die in der Terraristik gepflegt werden. Systematik dieser Reptilien, ihre Biologie und das Verhalten werden nach den neuesten wissenschaftlichen Erkenntnissen dargestellt. Porträts von über 100 Geckoarten mit vielen Farbfotos vervollständigen dieses alle Aspekte umfassende Werk.

Inhaltsverzeichnis:

  • Lebensweise und Verbreitung der Geckos
  • Entwicklungsgeschichte und Systematik
  • Besonderheiten des Körperbaues
  • Terrarien für Geckos und ihre Einrichtung
  • Fortpflanzung und Aufzucht
  • Inkubationstemperatur und Geschlechterverhältnis
  • Ernährung und Futtertierzuchten
  • Erkrankungen und ihre Behandlung
  • Vorstellung der einzelnen Geckoarten
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