Chelodina oblonga Gray 1841 – Northern Snake-Necked Turtle.

In: Rhodin, A.G.J., Pritchard, P.C.H., van Dijk, P.P., Saumure, R.A., Buhlmann, K.A., Iverson, J.B., and Mittermeier, R.A. (Eds.). Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. Chelonian Research Monographs No. 5, pp. 077.1–13, doi:10.3854/crm.5.077.oblonga.v1.2014, http://www.iucn-tftsg.org/cbftt/.

Summary:

The Northern Snake-necked Turtle, Chelodina (Macrochelodina) oblonga (Family Chelidae), until very recently known as C. (M.) rugosa, is a fairly large freshwater turtle (carapace length to 360 mm) with a broad distribution in tropical northern Australia and southern New Guinea. Its preferred habitats are seasonal wetlands on the coastal floodplains and adjacent hinterlands. These habitats undergo extensive flooding during the tropical wet season, with declining water levels during the following dry season; many waterholes dry completely. The species survives the dry season by migrating to permanent water or by estivating under the mud of dried waterholes. It is a highly prized food item among Aboriginal people, and turtles are collected each year in a harvest that has occurred for many millennia. The species is exclusively carnivorous and feeds on a range of fast-moving aquatic invertebrates, tadpoles, and fish. It is a highly fecund, fast-growing, and early-maturing species in comparison to most other Australian chelids. Its habit of nesting underwater makes it unique among all turtles. Nesting commences in the wet season (February) and is mostly complete by July (mid-dry season), though gravid females can be found as late as September if waterholes remain inundated. Eggs are laid in holes dug in mud under shallow water in the littoral zone of flooded waterholes. Embryonic development remains arrested while the nest remains flooded, but recommences when floodwaters recede and the ground dries. Embryonic development proceeds during the dry season and hatchling emergence coincides with the heavy rainfall or flooding in the following wet season. The species remains common in all the major river systems across northern Australia and southern New Guinea, and is sustainably harvested for traditional consumption in Australia, but is under some threat there from pig predation.

Chelodina  longicollis (Shaw  1784) – eastern  long-necked  turtle, common long-necked turtle, common snake-necked turtle.

In: Rhodin, A.G.J., Pritchard, P.C.H., van Dijk, P.P., Saumure, R.A., Buhlmann, K.A., Iverson, J.B., and Mittermeier, R.A. (Eds.). Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. Chelonian Research Monographs 5: 031.1-031.8, doi:10.3854/crm.5.031.
longicollis.v1.2009, http://www.iucn-tftsg.org/cbftt/.

Summary:

The eastern long-necked turtle, Chelodina longicollis (Family Chelidae), has a wide distribution throughout southeastern Australia. It occupies a broad range of freshwater aquatic habitats but is more abundant in shallow, ephemeral wetlands often remote from permanent rivers. Its propensity for long distance overland migration, coupled with a low rate of desiccation and the capacity to estivate on land, enable it to exploit highly-productive ephemeral habitats in the absence of competition from fish and other turtle species. In wetter periods, such habitats provide optimal conditions for growth and reproduction. In drier periods, however, turtles may need to seek refuge in permanent water where high population densities and low productivity can lead to reduced growth rates and reproductive output. The species is an opportunistic carnivore that feeds on a broad range of plankton, nekton and benthic macro-invertebrates, carrion, as well as terrestrial organisms that fall upon the water. It is relatively slow to mature (7–8 yrs for males and 10–12 yrs for females), lays between 6 and 23 hard-shelled eggs during spring and late summer, and can produce up to 3 clutches per year. Although currently considered common and not under major threat, the most widespread conservation concern for C. longicollis is high nest predation from the introduced fox (Vulpes vulpes), and roads, pest fencing, and habitat changes brought about by prolonged drought and climate change, which present localized and potential future threats for certain populations.

On some new species freshwater tortoises from North America, Ceylon and Australia.

Ann. Mag. Nat. Hist. (2) 18: 263-268.

Inhalt:

In dem Artikel werden v erschiedene Gattungen revidiert, so etwa Pseudemys von emys getrennt und verschiedene neue Arten beschrieben, darunter Chelodina colliei und Chelodina sulcata

North American Recent Soft-shelled Turtles (Family  Trionychidae)

University of Kansas Publications, Museum of Natural History 13 (10): 429-611.

Summary (Auszug):

In North America, soft-shelled turtles (genus Trionyx) occur in northern México, the eastern two-thirds of the United States, and extreme southeastern Canada. The genus fits the well-known Sino-American distributional pattern. In North America there are four species. Three (ferox, spinifer and muticus) are well-differentiated [591] and one (ater) is not well-differentiated from spinifer. Characters of taxonomic worth are provided by the following: size; proportions of snout, head and shell; pattern on carapace, snout, side of head, and limbs; tuberculation; sizes of parts of skull; number of parts of carapaces; and, shape and number of some parts of plastra. Many features show geographical gradients or clines. T. ferox is the largest species and muticus is the smallest. Females of all species are larger than males. With increasing size of individual, the juvenal pattern is replaced by a mottled and blotched pattern in females of all species; adult males of spinifer retain a conspicuous juvenal pattern, whereas the juvenal pattern is sometimes obscured or lost on those of ferox and muticus. The elongation of the preanal region in all males, and the acquisition of a "sandpapery" carapace in males of spinifer occur at sexual maturity. There is a marked secondary sexual difference in coloration in a population of T. s. emoryi (side of head bright orange in males and yellow in females). The sex of many hatchlings of T. s. asper can be distinguished by the pattern on the carapace. Slight ontogenetic variation occurs in some proportional measurements. Large skulls of ferox and some asper (those in Atlantic Coast drainages) have expanded crushing surfaces on the jaws. Considering osteological characters, muticus is most distinct; there is less difference between ferox and spinifer than between those species and muticus.

Taxonomy and nomenclature of the longneck turtle (genus Chelodina) from south-western Australia.

Records of the Western Australian Museum 25: 449–454
DOI 10.18195/issn.0312-3162.25(4).2010.449-454

Abstract:

Gray (1856) recognised Chelodina colliei from south-western Australia as a different species from Chelodina oblonga Gray, 1841 from ‘Western Australia’. In addition, Gray (1873) specifically mentioned specimens of C. oblonga from the Port Essington region of today’s Northern Territory. Boulenger (1889) synonymized C. colliei with C. oblonga, a view followed by later reviewers for over seven decades. Goode (1967) and Burbidge (1967) both reinstated Gray’s original concept that the longneck turtle of south-western Australia represents a distinct species, but erroneously applied and restricted the name C. oblonga to the south-western Australian species. Thomson (2000) detected this nomenclatural error and subsequently applied to the International Commission on Zoological Nomenclature (ICZN case 3351, Thomson 2006) to give precedence to rugosa over oblonga whenever the two were considered to be conspecific and to place on the official lists the names colliei, oblonga and rugosa, thus leaving colliei as the only available name for the south-western Australian Chelodina. Since then, the name Chelodina colliei was again used by several authors for the south-western Australian taxon, including in books and checklists (Bonin et al. 2006; Fritz and Havaš 2007; Iverson 2007). With case 3351 still under consideration by the ICZN, McCord and Joseph-Ouni (2007) further aggravated the nomenclatural confusion regarding the south-western Australian longneck turtle by fixing a ‘neotype’ for C. oblonga and by describing the genus Macrodiremys for C. oblonga (= colliei), both actions in violation of Articles 75.6 and 82.1 of the 1999 ICZN Code.

Geochelone platynota (Blyth 1863) – Burmesische Sternschildkröte, Kye Leik.

Chelonian Research Monographs 5, doi 10.3854/crm.5.057.platynota.vl.2011.

Die Burmesische Sternschildkröte, Geochelone platynota (Familie Testudinidae) ist eine mittelgroße Landschildkröte (Carapaxlänge etwa 30 cm), die die Trockenzone von Zentralmyanmar endemisch besiedelt. Wenig ist bezüglich ihrer Ökologie im natürlichen Habitat bekannt. Die Art lebt in so genannten xerophytischer (Trocken-) Vegetation, die typisch für die Trockenzone ist, besiedelt aber auch Grasland und gut genutzte Weiden und Hecken sowie landwirtschaftlich genutzte Felder. Ihre Nahrung besteht meist aus Gras und anderer Vegetation, aber Früchte, Pilze, Schnecken und Insekten werden auch gefressen und im Kot nachgewiesen. Die Paarungen erfolgen von Juni bis September gefolgt von Eiablagen von Oktober bis Februar. Die durchschnittliche Eizahl pro Gelege (n=27) lag bei 4,4 Eier, und es gab eine positive Korrelation zwischen der Größe der Weibchen und der Gelegegröße. Basierend auf den Daten, die an einer begrenzten Anzahl an Tieren erhoben werden konnten, ist die Home Range (genutzte Habitatfläche) für die Männchen größer als für Weibchen. Während der kühlen und trockenen Jahreszeit sinkt die Aktivität, und die Schildkröten ruhen im Bambusdickicht, unter Überhängen oder steinigen Höhlen. Geochelone platynota lebt makro- und mikrosympatrisch mit Indotestudo elongata in der Trockenzone, aber die ökologischen Beziehungen zwischen den beiden Arten sind kaum verstanden. Die wenigen Daten, die es gibt, lassen vermuten, dass G. platynota in der Wildnis mittlerweile als ökologisch ausgerottet angesehen werden muss. Dies ist das Ergebnis der aus der Historie bekannten lang anhaltenden Nutzung als Nahrung und dem in jüngster Zeit stark forcierten, illegalen Absammeln der Tiere für die internationalen Nahrungsmittel- und Haustiermärkte. Die letzten bekannten wild lebenden Populationen in den Schutzgebieten Shwe Settaw und Minzontaung sowie in Myaleik Taung sind nun so stark dezimiert, dass sie nicht mehr überlebensfähig sind. Zukünftige Erhaltungsmaßnahmen hängen davon ab, ob es gelingt, Methoden zur Nachzucht in menschlicher Obhut vor Ort in Myanmar zu entwickeln und entsprechende Wiederauswilderungsprogramme zu etablieren. Derzeit werden Nachzuchten in verschiedenen Einrichtungen in Myanmar erbrütet, allerdings verhindert die anhaltende Wilderei die Wiederansiedlung der Schildkröten in den Schutzgebieten.

platt-biblio

Zur Biologie und Haltung der Aldabra-Riesenschildkröte (Geochelone gigantea) und der Galapagos-Riesenschildkröte (Geochelone elephantopus) in menschlicher Obhut unter besonderer Berücksichtigung der Fortpflanzung.

Vet. med. Diss. TiHo Hannover
Aus dem Institut für Zoologie der Tierärztlichen Hochschule Hannover und dem Zoo Hannover
Wissenschaftliche Betreuung; Univ.-Porf. Dr, K. Wächtler
229 Seiten, 28 Tabelle, Anbbildungen, Anhang

Volltext

Zusammenfassung:

Die vorliegende Arbeit fasst den aktuellen Kenntnisstand zu den Riesenschildkrötenarten G. gigantea und G. elephantopus unter besonderer Berücksichtigung der Fortpflanzungsbiologie zusammen. Dabei wird ein umfassender Überblick über die hierzu verfügbare Literatur gegeben. Im Rahmen einer zwischen Februar und August 2000 durchgeführten weltweiten Umfrage wurden darüber hinaus die aktuellen Haltungsbedingungen, die Fütterung, das Management sowie der Reproduktionsstatus in 67 Haltungen von G. gigantea und 26 Haltungen G. elephantopus erfasst. Dabei wurde der Aktivitätsbeeinflussung durch das Management besondere Bedeutung beigemessen, da ein Zusammenhang zur Fortpflanzungsaktivität vermutet wird und ein großer Unterschied zwischen der Aktivität der Tiere im natürlichen Lebensraum und in menschlicher Obhut besteht. Halter gemischtgeschlechtiger Gruppen und Züchter bewerteten außerdem die mögliche Relevanz fortpflanzungsbeeinflussender Faktoren.

Anhand der Befragung wurde neben der Ermittlung des Status Präsens auch die praktische Umsetzung der aus der Lebensweise der Tiere im Freiland abgeleiteten Grundsätze bzw. der in der Literatur vorgegebenen Haltungsempfehlungen überprüft. Zudem wurden potentielle fortpflanzungsspezifische Einflussfaktoren statistisch auf einen Zusammenhang zum Vorkommen von Eiablagen untersucht. Weiterhin wurden Ultraschall- und Spermienuntersuchungen der im Zoo Hannover gehaltenen G. gigantea durchgeführt.

Bei der existierenden Literatur zu Haltung, Fütterung und Fortpflanzung in menschlicher Obhut handelt es sich meist um Fallbeschreibungen und empirische Einschätzungen. Nur zu wenigen Teilaspekten liegen wissenschaftliche Untersuchungen vor. Kenntnisse der Umweltfaktoren, Ernährung und Lebensweise sowie der damit verknüpften physiologischen, ökologischen und sozialen Zusammenhänge bilden aber die Grundlage für eine artgerechte Haltung und für Zuchterfolge.

Die Gesamtheit der Haltungen weist aufgrund der weltweiten Verteilung der Zoos und Privathalter sowie der unterschiedlichen lokalen Voraussetzungen ein sehr breit gefächertes Spektrum von Haltungsbedingungen sowie Fütterung und Management auf. Innerhalb dieses Spektrums gelingen Zuchterfolge unter sehr variablen Bedingungen. Faktoren, die von vielen Haltern und Züchtern beider Arten als besonders wichtig angesehen werden, sind: klimatische Faktoren (Licht, allgemeine Wetterverhältnisse, Lufttemperatur), Gehegegröße und Komfort, Futterzusammensetzung, Gruppengröße, Geschlechtertrennung sowie Aktivität und Fitness der Männchen. Die Fortpflanzung von Riesenschildkröten stellt sich insgesamt als polyfaktoriell bestimmtes Geschehen dar. Statistisch belegt werden konnte ein signifikanter Zusammenhang zwischen der Durchführung einer temporären Geschlechtertrennung und dem Vorkommen von Eiablagen.

Die im Zoo Hannover durchgeführten praktischen Untersuchungen an G. gigantea belegen eine Ovulationshemmung bei allen gehaltenen Weibchen und bestätigen damit frühere Untersuchungen (Zürich 1995). Unter Einbeziehung des in der Befragung ermittelten weltweiten geringen Anteils von Weibchen mit Eiablagen müssen als Hauptursache ausbleibender Zuchterfolge nachteilige Umwelteinflüsse auf die Ovulation angenommen werden.

Im Vergleich zwischen Freilandbedingungen und heutigem Haltungsstandart ergeben sich in verschiedenen Bereichen Verbesserungsvorschläge. Diese betreffen insbesondere einen physiologischen Temperaturgradienten im Innengehege, eine ausreichende UV-Versorgung während der Innenhaltung, eine Aktivitätsanregung der Tiere durch entsprechende Gehegegestaltung und einen variablen Fütterungsmodus, eine artspezifische Fütterung sowie ein an den durch Gruppengröße, Geschlechterverhältnis und Haltungsdichte entstehenden sozialen Interaktionen orientiertes Management. Unter dem Gesichtspunkt der Fortpflanzung sind Aktivitätsanregung, Fütterung und Management besonders zu beachten.

Summary:

”Biology and keeping of the Aldabra giant tortoise (Geochelone gigantea) and the Galapagos giant tortoise (Geochelone elephantopus) in captivity with special reference to reproduction” (by Katja Ebersbach)

This study summarises the current knowledge concerning the two species of giant tortoises G. gigantea and G. elephantopus with special regard to reproductive biology. A comprehensive survey of the literature available is given. In addition, the current keeping conditions, feeding, management and reproductive status of 67 maintenance systems of G. gigantea and 26 maintenance systems of G. elephantopus were recorded during a worldwide inquiry that has been carried out between February and August 2000. For two main reasons the stimulation of activity by management was of special importance: First, a connection with reproductive activity can be assumed. Second, there exists a significant difference between the activity of giant tortoises living free and those kept in captivity. Furthermore, keepers of mixed sex groups and breeders evaluated the possible relevance of factors influencing reproduction. Using the inquiry, not only the present standard of maintenance was investigated, but also the practical realisation of principles derived from the animals natural habitat and from recommendations given in the literature. Additionally, correlations between factors potentially influencing reproduction and the occurrence of egg laying were tested, applying statistic methods. Furthermore, ultrasonography and examination of spermatozoa of G. gigantea kept at Hannover Zoo were carried out.

The majority of the surveyed literature on keeping, feeding and reproduction in captivity deals with case descriptions and empirical assessments. Scientific investigation has been done with regard to a few aspects only. However, knowledge concerning environmental factors, feeding, biology, and the physiological, ecological, and social context is the basis for a standart of maintenance appropriate to the species and for breeding success.

Due to worldwide distribution and different local conditions, the surveyed maintenance systems (zoos and private keepers) represent a very wide spectrum of keeping conditions, feeding and management. Within this spectrum breeding success is reached under variable conditions. Factors mentioned by many keepers and breeders of both species to be especially important are: Climatic factors (light, general weather conditions, air temperature), size of enclosure, comfort, food composition, size of group, separation of sexes, and the males’ activity and fitness. Hence, the reproduction of giant tortoises is a process influenced by many factors. A significant connection between temporary separation of the sexes and the occurrence of egg laying has been demonstrated statistically.

The sonographic investigation of G. gigantea at Hannover Zoo proves the inhibition of ovulation concerning all females and, thus, corresponds with earlier research (Zürich 1995). Taking into account the small number of egg laying females worldwide, negative environmental influence on the ovulation must be regarded as the main cause of lacking breeding success.

Comparing natural conditions and recent standards of maintenance recommendations for improvement can be deduced. In particular, they concern a physiological temperature gradient within the inside enclosure, sufficient supply with UV-radiation during indoor housing, stimulation of activity through appropriate design of the enclosure and varied kinds of feeding, adequate food, and management considering the social interactions resulting from group size, sex ratio and keeping density. With regard to reproduction stimulation of activity, adequate food and management are of special importance.

ebersbach-biblio

Observations  on  the  South  American  yellow-footed tortoise (Chelonoidis denticulata) in French Guiana.

RADIATA 20(2): 18-32.

Conclusion:

Although the species Chelonoidis denticulata has  ong been known to terrarium enthusiasts, it has (unjustly) been regarded as somehow inferior to the more popular red-footed tortoise. Its behaviour is nevertheless very interesting, to say the least – be it in human care or in the wild. Generally speaking, it is warmly recommended to every ambitious keeper of wild animals, if at all possible, to also try and observe his favourite animals in their natural environment. Although this will not provide quite the same degree of intimate insight into the life of these animals, the impressions  you expose yourself to during a stay in the natural habitat will contribute substantially to optimising the husbandry conditions for the specimens in your care at home.

Kinixys erosa (Schweigger 1812) – Forest Hinge-back Tortoise, Serrated Hinge-back Tortoise, Serrated Hinged Tortoise.

In: Rhodin, A.G.J., Pritchard, P.C.H., van Dijk, P.P., Saumure, R.A., Buhlmann, K.A., Iverson, J.B., and Mittermeier, R.A. (Eds.). Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. Chelonian Research Monographs 5(7):084.1–13, doi:10.3854/crm.5.084.erosa.v1.2014, http://www.iucn-tftsg.org/cbftt/.

Summary:

The Forest Hinge-back Tortoise, Kinixys erosa (Family Testudinidae), is a forest tortoise with considerable range over the continuous Guinea–Congo rainforest region in West and Central Africa. It is a medium-sized to large tortoise, with a carapace length reaching ca. 400 mm, and males larger than females. Tortoises of the genus Kinixys can close themselves entirely within their shells through a unique posterior carapacial hinge. Kinixys erosa inhabits the lowland evergreen forest, marshy areas, and forest galleries growing along rivers and streams, where it is locally threatened by clearance of forest for cultivation and hunting pressure. It has an omnivorous diet, with mushrooms being predominant. Population sizes are strongly depressed in areas where these tortoises are actively hunted by human populations. The main threats for this species include subsistence hunting by local people in desperately poor economic conditions, agricultural and industrial expansion with deforestation, and trade for the pet industry. There is a strong need for more field research on K. erosa ecology, abundance, and status. There are no known conservation actions for this species; however, there is a need to establish protected areas that include viable populations of these tortoises through their natural range.

Distribution. – Angola, Benin, Cameroon, Central African Republic, Congo (Democratic Republic of Congo–DRC), Congo (Republic of Congo–ROC), Equatorial Guinea, Gabon, Ghana, Guinea, Ivory Coast (Côte d’Ivoire), Liberia, Nigeria, Sierra Leone, Togo, Uganda. Widely distributed along coastal forested West Africa from Sierra Leone and Guinea through the Congo Basin of central Africa to northern Angola.

Synonymy. – Testudo erosa Schweigger 1812, Kinixys erosa, Cinixys erosa, Kinixys belliana erosa, Testudo schoepfii Fitzinger 1826 (nomen nudum), Kinixys castanea Bell 1827, Cinixys (Cinixys) castanea, Cinixys castanea.

Subspecies. – None recognized.

Status. – IUCN 2014 Red List: Data Deficient (DD, assessed 1996); TFTSG Draft Red List: Endangered (EN, assessed 2013); CITES: Appendix II, as Testudinidae spp.

Chersina angulata (Schweigger 1812) – Angulate Tortoise, South African Bowsprit Tortoise.

In: Rhodin, A.G.J., Pritchard, P.C.H., van Dijk, P.P., Saumure, R.A., Buhlmann, K.A., Iverson, J.B., and Mittermeier, R.A. (Eds.). Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. Chelonian Research Monographs No. 5, pp. 030.1-030.6, doi:10.3854/crm.5.030.angulata.v1.2009, http://www.iucn-tftsg.org/cbftt/.

Summary:

The  angulate  or  bowsprit  tortoise, Chersina angulata (Family Testudinidae), is endemic to southern Africa and is the type species of the monotypic genus. No subspecies are distinguished, but mtDNA markers indicate the presence of two distinct evolutionary lineages associated with the southern and western regions of South Africa, respectively. The species is medium-sized (carapace length to ca. 350 mm), sexually dimorphic with males larger than females, characterized by  a  large,  protruding,  undivided  gular  scute,  and  displays  substantial  color  and  size  variation.
The species is active throughout the year but temperature and rainfall modify its activity patterns. Males appear to establish dominance hierarchies in spring when they use their large gular scute to overturn rival conspecific males. Females produce single-egg clutches from late summer to late
spring and can lay up to six clutches annually. Egg retention time varies substantially and correlates with temperature and rainfall. The diet includes a wide range of angiosperms as well as mosses, mushrooms, insects, snails, and animal feces. They are selective feeders and their diet changes with season and site.

Chersina angulata is not threatened and is adequately protected.

Distribution. – Namibia, South Africa. The range extends along the southern and western regions of South Africa into southwestern Namibia.

Synonymy. – Testudo angulata Schweigger 1812, Testudo (Chersina) angulata, Chersina angulata, Goniochersus angulata, Neotestudo angulata, Chersine angulata, Testudo bellii Gray 1828, Chersina angulata pallida Gray 1831

Subspecies. – No subspecies currently recognized.

Status. – IUCN 2008 Red List: Not Listed (= Least Concern, LR/lc) (assessed 1996, needs updating); CITES: Appendix II (as Testudinidae spp.); South African Red Data Book: Not Listed.