Crocodiles in the Sahara Desert: An Update of Distribution, Habitats and Population Status for Conservation Planning in Mauritania.

PLoS ONE. 6 (2)
Published: February 25, 2011. DOI: 10.1371/journal.pone.0014734

Background

Relict populations of Crocodylus niloticus persist in Chad, Egypt and Mauritania. Although crocodiles were widespread throughout the Sahara until the early 20th century, increased aridity combined with human persecution led to local extinction. Knowledge on distribution, occupied habitats, population size and prey availability is scarce in most populations. This study evaluates the status of Saharan crocodiles and provides new data for Mauritania to assist conservation planning.

Methodology/Principal Findings

A series of surveys in Mauritania detected crocodile presence in 78 localities dispersed across 10 river basins and most tended to be isolated within river basins. Permanent gueltas and seasonal tâmoûrts were the most common occupied habitats. Crocodile encounters ranged from one to more than 20 individuals, but in most localities less than five crocodiles were observed. Larger numbers were observed after the rainy season and during night sampling. Crocodiles were found dead in between water points along dry river-beds suggesting the occurrence of dispersal.

Conclusion/Significance

Research priorities in Chad and Egypt should focus on quantifying population size and pressures exerted on habitats. The present study increased in by 35% the number of known crocodile localities in Mauritania. Gueltas are crucial for the persistence of mountain populations. Oscillations in water availability throughout the year and the small dimensions of gueltas affect biological traits, including activity and body size. Studies are needed to understand adaptation traits of desert populations. Molecular analyses are needed to quantify genetic variability, population sub-structuring and effective population size, and detect the occurrence of gene flow. Monitoring is needed to detect demographical and genetical trends in completely isolated populations. Crocodiles are apparently vulnerable during dispersal events. Awareness campaigns focusing on the vulnerability and relict value of crocodiles should be implemented. Classification of Mauritanian mountains as protected areas should be prioritised.

Rediscovery of relict populations of the Nile crocodile Crocodylus niloticus in south-eastern Mauritania, with observations on their natural history.

ORYX 35 (3): 260–262.

Article first published online: 20 DEC 2001 | DOI: 10.1046/j.1365-3008.2001.00187.x

Abstract:

In 1998 and 1999, relict populations of the Nile crocodile Crocodylus niloticus were rediscovered in south-eastern Mauritania, 70 years after the last reports of their existence and 6 years after the IUCN Species Survival Commission listed them as extirpated in that country. Crocodiles were found in four different types of wetlands, herein described. Preliminary observations on their natural history and their interactions with humans are provided, and the main threats and the prerequisites for their protection are discussed.

shine-biblio

A comparative study of crocodile lizards (Shinisaurus crocodilurus Ahl, 1930) from Vietnam and China.

Raffl. Bull. Zool. 56(1): 181 – 187.

Abstract:

Preliminary morphological comparisons between Chinese and Vietnamese Shinisaurus representatives showed no significant differences that would justify a separate taxonomic status of the single known Vietnamese population. Also first mitochondrial DNA sequence comparisons showed very low differentiation therefore, being likely to represent the same taxon. In addition, we provide further information about the habitat, and preliminary data concerning the reproduction and feeding ecology of Vietnamese S. crocodilurus. We further stress biogeographical and conservational aspects of the endangered species in Vietnam.

PDF Download available from: https://www.researchgate.net/publication/237286590_A_comparative_study_of_crocodile_lizards_Shinisaurus_crocodilurus_AHL_1930_from_Vietnam_and_China [accessed Jul 13, 2017].

ziegler-biblio

First record of the Chinese crocodile lizard from outside of China: Report on a population of Shinisaurus crocodilurus Ahl, 1930 from North-eastern Vietnam.

Hamadryad, Tamil Nadu 27(2): 193 – 199.

Ungiftige Schlangen - Schlangen im Terrarium.

Band 1, Teil 1.

Band 1, Teil 2.

312+316 Seiten; 248 Farbfotos. 4. neu bearbeitete Auflage. Verlag Ulmer, Stuttgart. ISBN-3-8001-3223-0.

Verlagstext:

Dieses Standardwerk liegt nun in der vierten, vollkommen überarbeiteten und stark erweiterten Auflage vor. Im ersten Teil werden folgende Kapitel behandelt:
- Schlangen in der Natur und in menschlicher Obhut
- rechtliche Fragen der Schlangenhaltung (von Rechtsanwalt Dietrich Rössel)
- Krankheiten der Schlangen
- Familie Xenopeltidae (Regenbogenschlangen)
- Familie Boidae (Riesenschlangen)
- Familie Acorchirdidae (Warzenschlangen)
- Familie Colubridae (Nattern)
Gattungen Natrix, Nerodia, Amphiesma, Rhabdobis, Xenochropis, Thamnophis, Tropidonophis.
Der zweite Teil enthält:
- Unterfamilie Natricinae ( Wassernattern und Verwandte)
- Unterfamilie Xenodontinae (Ungleichzähnige Nattern)
- Unterfamilie Colubrinae (Land- und Baumnattern)

trutnau-biblio

A molecular phylogeny of the African plated lizards, genus Gerrhosaurus Wiegmann, 1828 (Squamata: Gerrhosauridae), with the description of two new genera.

Zootaxa 3750 (5): 465–493. DOI: http://dx.doi.org/10.11646/zootaxa.3750.5.3   

Abstract:

We constructed a molecular phylogeny of the African plated lizard family Gerrhosauridae using two mitochondrial markers (ND2, 732 bp; 16S, 576 bp) and one nuclear marker (PRLR, 538 bp). This analysis showed that the subfamily Gerrhosaurinae consists of five major clades which we interpret as representing five genera. The genera Tetradactylus and Cordylosaurus were each recovered as monophyletic, but Gerrhosaurus as currently conceived is paraphyletic, consisting of three distinct genus-level assemblages. The two clades consisting of Gerrhosaurus major Duméril, 1851 and Gerrhosaurus validus Smith, 1849 are both described here as new genera, namely Broadleysaurus Bates & Tolley gen. nov. and Matobosaurus Bates & Tolley gen. nov., respectively. Two subspecies of ‘Gerrhosaurus major’ that were historically separated on the basis of differences in colour pattern are not reciprocally monophyletic, so Gerrhosaurus bottegoi Del Prato, 1895 is relegated to the synonomy of Broadleysaurus major (Duméril, 1851) comb. nov., which is rendered monotypic. Gerrhosaurus validus maltzahni De Grys, 1938 is genetically and morphologically well differentiated from G. v. validus and the two taxa also occur in allopatry. We therefore re-instate the former as Matobosaurus maltzahni (De Grys, 1938) comb. nov., rendering Matobosaurus validus (Smith, 1849) comb. nov. a monotypic species. Our analysis also showed that Gerrhosaurus sensu stricto comprises two major subclades, one consisting of Gerrhosaurus typicus (Smith, 1837) + Gerrhosaurus skoogi Andersson, 1916, and the other containing the remaining species. In this latter subclade we show that west-Central African Gerrhosaurus nigrolineatus Hallowell, 1857 is most closely related to Gerrhosaurus auritus Boettger, 1887 rather than to G. nigrolineatus from East and Southern Africa. The west-Central African clade of G. nigrolineatus differs from the East and Southern African clade by a p-distance of 13.0% (ND2) and 6.9% (16S), and can be differentiated morphologically. We accordingly apply the name Gerrhosaurus intermedius Lönnberg, 1907 comb. nov. to populations from Kenya, Uganda, Rwanda, Tanzania, Malawi, Mozambique, Zimbabwe and South Africa previously identified under the name G. nigrolineatus. Our analysis also confirms that Gerrhosaurus bulsi Laurent, 1954 is a distinct species and sister taxon to a clade containing G. nigrolineatus, G. auritus and G. intermedius. The latter four taxa form a closely-related ‘G. nigrolineatus species complex’ with a widespread distribution in Africa. Most closely related to this complex of species is Gerrhosaurus flavigularis Wiegmann, 1828 which has an extensive range in East and Southern Africa, and displays genetic substructure which requires further investigation. The status of Gerrhosaurus multilineatus Bocage, 1866, and Angolan populations referred to G. nigrolineatus, remains problematic.

bates-biblio

Die Europäische Sumpfschildkröte (Emys lutaria Marsili). Ihr Vorkommen in der schweizerischen Hochebene und ihr Leben im Aquarium und im Terrarium. Eine biologische Studie nach Tagebuchnotizen. 

Sonderabdruck aus der Zeitschrift "Der Zoologische Garten". Verlag Mahlau & Waldschmidt, Frankfurt. 24 Seiten.

Volltext (PDF)

fischer-sigwart-biblio

Intellagama lesueurii (Gray, 1831), the correct binomial combination for the Australian Eastern Water Dragon (Sauria, Agamidae).

Zootaxa 3390: 65–67. ISSN 1175-5326 (print edition), ISSN 1175-5334 (online edition)

The Eastern Water Dragon is a large, conspicuous agamid, well known to many inhabitants of eastern Australia. It was first described in the scientific literature as Lophura lesueurii by Gray (1831). Gray’s allocation of this taxon to his earlier genus Lophura Gray, 1827, created for the species Lacerta lophura Shaw, 1802, does not mention that Cuvier (1829) had erected Istiurus for amboinensis Schlosser, 1768, which Cuvier treated as a senior synonym of Lophura.

Cuvier considered the generic name Lophura to be too similar to Lophyrus Latreille, 1802, a genus of conifer sawflies belonging to the family Diprionidae, hence the need for a new genus. Both Gray and Cuvier were evidently unaware that Lophura was unavailable as this name had already been assign ed to a genus of phasianid birds (Fleming 1822). The Eastern Water Dragon has subsequently appeared in the taxonomic literature under the following synonyms: Iguana paramatensis Fitzinger, 1843; Amphibolurus maculiferus Girard, 1857; Amphibolurus heterurus Peters, 1866 and Amphibolurus branchialis De Vis, 1884. The combination Physignathus lesueurii was first used in 1845 by Gray in his Catalogue of the Specimens of Lizards in the British Museum and has been in use ever since. The only other generic name proposed for this taxon is Intellagama Wells and Wellington, 1985, by which the authors implied its distinctiveness from the other member of Physignathus,  the Chinese Water Dragon P. cocincinus Cuvier, 1829. However, as their description provided no evidence to demons trate that Australian water dragons are generically distinct from their foreign congener, this name has not been adopted by subsequent authors, and has been informally treated as a synonym of Physignathus. ....

Atlas zu der Reise im nördlichen Afrika.
Erste Abtheilung Zoologie. Reptilien.

bearbeitet von C.H.G. von HEYDEN.
Herausgegeben von der Senckenbergischen naturforschenen Gesellschaft. Frankfurt am Main.
Gedruckt und in commission bei H. L. Brönner, 1826-28.

Volltext

rüppell-biblio

Leguane - faszinierend und exotisch.

4. Auflage (1. Auflage 2003); 64 Seiten, zahlreiche Farbfotos von Christine Steimer

Verlag Graefe & Unzer GmbH, München. ISBN 978-3-7742-5758-9.

Verlagstext:

Filme wie Jurassic Park haben Echsen ins Bewusstsein vieler Menschen gebracht. Leguane faszinieren uns, denn sie erinnern an die Saurier aus längst vergangenen Zeiten. Verbunden mit dem Wunsch immer Ausgefalleneres besitzen zu wollen, sind Terrarientiere – und damit auch Leguane – heute “en vogue”. Mit der richtigen Pflege und Haltung zeigen sie vielfältige und interessante Verhaltensweisen und werden damit für Ihre Halter zum spannenden Beobachtungsobjekt. Dieser GU Tierratgeber vermittelt alles Wichtige rund um die Themen Einrichtung und Technik, Ernährung und Pflege – damit Sie Ihrem Leguan ein artgerechtes Leben bieten können.