:Black marsh turtle

Formerly under the genus Emys, black marsh turtles are now classified under Siebenrockiella. They were first described by the British zoologist John Edward Gray from three specimens from the collections of Thomas Bell.{{cite journal|last1=Nowak-Kemp|first1=Malgosia|last2=Fritz|first2=Uwe|year=2010|title=Chelonian type specimens at the Oxford University Museum|journal=Zootaxa|volume=2604|pages=1–19|publisher=Magnolia Press|issn=1175-5334|url=http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Nowak-Kemp_and_Fritz_2010.pdf|doi=10.11646/zootaxa.2604.1.1|archive-url=https://web.archive.org/web/20120316212137/http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Nowak-Kemp_and_Fritz_2010.pdf|archive-date=16 March 2012}} Black marsh turtles used to be monotypic within the genus Siebenrockiella until Diesmos et al. (2005) showed based on genetic studies and morphology, that the recently rediscovered and critically endangered Philippine forest turtles, until that time known as Heosemys leytensis, were actually very closely related. Philippine forest turtles were subsequently reassigned to Siebenrockiella under the subgenus Panyaenemys.

• {{cite journal|author1=Diesmos, Arvin C.|author2=Parham, James F.|author3=Stuart, Bryan L.|author4=Brown, Rafe M.|year=2005|url=http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Diesmos_etal_2005.pdf|title=The Phylogenetic Position of the Recently Rediscovered Philippine Forest Turtle (Bataguridae: Heosemys leytensis)|journal=Proceedings of the California Academy of Sciences|volume=56|issue=3|pages=31–41}}
• {{cite journal|author1=Yasukawa, Yuichirou|author2=Ota, Hideyoshi|name-list-style=amp|year=2009 |title=Geoemyda spengleri (Gmelin 1789) – Black-Breasted Leaf Turtle|journal=Chelonian Research Monographs|number=5|publisher=Conservation Biology of Freshwater Turtles and Tortoises|issn=1088-7105|doi=10.3854/crm.5.047.spengleri.v1.2010 |doi-access=free |pages=047.1–047.6|isbn=978-0-9653540-9-7}}
• Bickham, J.W., Parham, J.F., Philippen, H., Rhodin, A.G., Shaffer, H.B., Spinks, P.Q. & Van Dijk, P.P. (2007).[http://www.eve.ucdavis.edu/shafferlab/monograph/TTWG.a.pdf "Turtle taxonomy: Methodology, recommendations, and guidelines"] {{webarchive|url=https://web.archive.org/web/20100610200944/http://www2.eve.ucdavis.edu/shafferlab/monograph/TTWG.a.pdf |date=10 June 2010 }}. In: Shaffer, H.B., FitzsSimmons, N.N., Georges, A., & Rhodin, A.G. (Eds.), "Proceedings of a workshop on genetics, ethics, and taxonomy of freshwater turtles and tortoises", Chelonian Research Monographs 4:73–84 {{doi|10.3854/crm.5.000.checklist.v3.2010}}. Retrieved 1 April 2011

They are classified under the subfamily Geoemydinae under the family Geoemydidae. Black marsh turtles are cryptodires, having the ability to pull their heads straight back into the shells; instead of folding their necks sideways along the body like in pleurodiran turtles.

The specific epithet "crassicollis" comes from Latin crassus ("thick") and collum ("neck"). The generic name was coined in honor of the Austrian zoologist Friedrich Siebenrock.{{cite web|url=http://reptile-database.reptarium.cz/species.php?genus=Siebenrockiella&species=crassicollis|title=Siebenrockiella crassicollis (GRAY, 1831)|last1= Uetz |first1=Peter|last2=Hallermann|first2=Jakob|last3= Hosek|first3=Jiri|publisher=The Reptile Database|access-date=31 March 2011}}

Siebenrockiella crassicollis are known by a variety of vernacular names among hobbyists, such as black terrapin, black mud turtle, Malaysian black mud turtle, fat-headed turtle, thick-necked turtle, and Borneo black leaf turtle. They are also known as kura-kura pipi-putih in Indonesian.{{cite journal |last1=Pasaribu |first1=Julita |last2=Ruyani |first2=Aceng |last3=Suhartoyo |first3=Hery |title=Studi perbandingan adaptasi Kura-Kura Pipi Putih (Siebenrockiella crassicollis) jantan dan betina di area Kolam Konservasi Universitas Bengkulu |journal=PENDIPA Journal of Science Education |date=28 February 2019 |volume=3 |issue=1 |pages=33–39 |doi=10.33369/pendipa.3.1.33-39 |url=https://ejournal.unib.ac.id/index.php/pendipa/article/view/6923|doi-access=free }}

File:Sieben crass 100118-0390 stgd.jpg.]]

File:Sieben crass 100118-0378 stgd.jpg

File:Sieben crass 100118-0384 stgd.jpg of a black marsh turtle.]]

Adult black marsh turtles are usually small to medium-sized, averaging at around {{convert|17|cm|in|abbr=on}} in length and rarely exceeding {{convert|20|cm|in|abbr=on}}. Some individuals, however, are known to grow to twice this size. The ovoid carapace (the dorsal shell) is widest just behind the middle portion, with a strongly serrated posterior margin. A prominent central ridge (known as keels) also runs through the middle of the carapace. Two lateral keels are present as well, though they are not always visible. The carapace is almost entirely black or dark brown with black radiating patterns.

The plastron (the ventral shell) is not hinged and has a shallow U-shaped notch in the pair of anal scutes. The bridge (the parts connecting the abdominal and pectoral scutes of the plastron to the carapace) is approximately the same length as the rear part of the plastron (consisting of the femoral and anal scutes). Both the bridge and the plastron can be entirely black, dark brown, or yellowish with splotches or patterns of darker colors.

The forelimbs are covered with large transverse scales. Both the forelimbs and the hind limbs are webbed, reflecting their largely aquatic habits. The necks of black marsh turtles are characteristically thick, forming a collar around the head when it is retracted into the shell. All of the limbs, the tail, and the neck are dark gray to black. The head is broad with a short upwardly pointed snout. It is mostly black on top with cream to yellow markings around the eyes and at the throat. It also has a pair of pale white to yellow spots just behind the tympanum, usually hidden behind the folds of the neck.{{cite web|url=http://www.asianturtlenetwork.org/field_guide/Siebenrockiella_crassicollis.htm|title=Siebenrockiella crassicollis|date=August 2006|publisher=Asian Turtle Conservation Network|access-date=1 April 2011}} The powerful jaws are pale yellow to pale brown in color and curves upwards, earning it the charming name of 'smiling terrapin'.{{cite web|url=http://www.ecologyasia.com/verts/turtles/black-marsh-terrapin.htm|title=Turtles of SE Asia: Black Marsh Terrapin|publisher=Ecology Asia|access-date=1 April 2011}}

Black marsh turtles are sexually dimorphic. Males have concave plastra in contrast to the flat plastron of females.{{cite web|url=http://nlbif.eti.uva.nl/bis/turtles.php?menuentry=soorten&id=268|title=Turtles of the World: Siebenrockiella crassicollis|author=Ernst, C.H.|author2=Altenburg, R.G.M.|author3=Barbour, R.W.|name-list-style=amp|publisher=Nederlandse tak van de Global Biodiversity Information Facility (NLBIF)|access-date=1 April 2011|archive-url=https://web.archive.org/web/20110320235607/http://nlbif.eti.uva.nl/bis/turtles.php?menuentry=soorten|archive-date=20 March 2011}} The markings around the eyes and throat, present in all juveniles, disappear among males upon reaching adulthood while they are retained in females. The tails are also longer and thicker for males than for females.{{cite web|url=http://www.eol.org/pages/460737|title=Siebenrockiella crassicollis Gray 1831, Black marsh turtle |publisher=Encyclopedia of Life|access-date=1 April 2011}}

Black marsh turtles have a diploid karyotype of 52 chromosomes. They are also notable for being the first turtle shown to exhibit an XX/XY system of chromosomal sex determination, specifically with macrochromosomes.{{cite journal | author = Carr J.L., Bickham J.W. | year = 1981 | title = Sex chromosomes of the Asian Black Pond Turtle, Siebenrockiella crassicollis (Testudines: Emydidae) | journal = Cytogenetics and Cell Genetics | volume = 31 | issue = 3| pages = 178–183 | pmid = 7326996 | doi=10.1159/000131644}}{{cite journal|author1=Girondot, Marc |author2=Zaborski, Patrick |author3=Servan, Jean |author4= Pieau, Claude |year=1994|title=Genetic contribution to sex determination in turtles with environmental sex determination|journal=Genetic Research, Cambridge|volume=62|issue=2 |pages=117–127|publisher= Cambridge University Press|doi=10.1017/S0016672300032225 |doi-access=free}} Very rare in turtles where the gender of developing embryos are usually determined by environmental temperatures.{{cite journal|author1=Ewert, Michael A. |author2=Nelson, Craig E. |name-list-style=amp |year=1991|jstor=1446248|title=Sex Determination in Turtles: Diverse Patterns and Some Possible Adaptive Values|journal=Copeia|volume=1991|issue=1|pages=50–69|publisher= American Society of Ichthyologists and Herpetologists|doi=10.2307/1446248}}

Black marsh turtles can be found in southern Vietnam, Cambodia, southern Myanmar (Tenasserim), central and peninsular Thailand, eastern and western Malaysia, Singapore, and the Indonesian islands of Java, Kalimantan, and Sumatra.Rhodin, A.G.J., van Dijk, P.P, Iverson, J.B., and Shaffer, H.B. (Turtle Taxonomy Working Group).2010. [https://web.archive.org/web/20110717125632/http://www.iucn-tftsg.org/wp-content/uploads/file/Accounts/crm_5_000_checklist_v3_2010.pdf "Turtles of the world, 2010 update: annotated checklist of taxonomy, synonymy, distribution, and conservation status"]. 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: 000.85–000.164, {{doi|10.3854/crm.5.000.checklist.v3.2010}}. Retrieved 25 March 2011. A specimen discovered in the Cerucuk River on Belitung Island in May 2023 is the first official record of the species on the island{{Cite journal |last1=Hasan |first1=Veryl |last2=South |first2=Josie |last3=Valen |first3=Fitri Sil |last4=Andriyono |first4=Sapto |date=2023-07-13 |title=Endangered Black Marsh Turtle, Siebenrockiella crassicollis (Gray, 1831) (Reptilia, Testudines, Geoemydidae): distribution extension and first record from Belitung Island, Indonesia |url=https://checklist.pensoft.net/article/106741/ |journal=Check List |language=en |volume=19 |issue=4 |pages=505–508 |doi=10.15560/19.4.505 |issn=1809-127X|doi-access=free }} and represents a significant range extension beyond previously recorded populations in Sumatra to the west and Borneo to the east.

Black marsh turtles live in slow-moving or stagnant warm waters with abundant vegetation – usually marshes, swamps, and ponds. As their common name implies, black marsh turtles are primarily aquatic and prefer to stay buried in soft mud when not feeding.{{cite web|url=http://www.turtlepuddle.org/exotics/crassicollis.html|title=Borneo Black Leaf Turtle Siebenrockiella crassicollis|author=Hopson, Mary|publisher=The Turtle Puddle|access-date=31 March 2011}}

Black marsh turtles are predominantly carnivorous and prefer to feed underwater. They prey on insects, worms, molluscs, amphibians, crustaceans, and small fish, though they will occasionally scavenge rotting plants, fruits, or carcasses of larger animals that fall into the water.{{cite web|url=http://www.arkive.org/black-marsh-turtle/siebenrockiella-crassicollis/#text=All|title=Black marsh turtle (Siebenrockiella crassicollis)|publisher=ARKive: Images of Life on Earth|access-date=1 April 2011|archive-url=https://web.archive.org/web/20110423204649/http://www.arkive.org/black-marsh-turtle/siebenrockiella-crassicollis/#text=All|archive-date=23 April 2011}}{{cite book|last =Franklin|first =Carl J.|title =Turtles: An Extraordinary Natural History 245 Million Years in the Making|publisher =Voyageur Press|year =2007|isbn =978-0-7603-2981-8|url=https://books.google.com/books?id=rBbuYFjiTNMC&q=cyclemys+elevation+wild&pg=PA109}} Juveniles are typically more carnivorous than adults.

Black marsh turtles are shy creatures. Mostly aquatic and nocturnal, they will sometimes come out to land at night to forage or mate, and occasionally during the day to bask. Majority of the time they prefer to stay underwater, partially buried in mud in shallow water or swimming near the bottom in deeper still waters.

When threatened, black marsh turtles excrete a foul-smelling secretion from their cloaca to ward off would-be predators.{{cite book| last =Gurley| first =Russ| title =Keeping and Breeding Freshwater Turtles| year =2002| publisher =Living Art Pub| isbn =978-0-9638130-3-9| chapter =Siebenrockiella crassicollis : Black Mud Turtle |chapter-url=http://www.asianturtle.org/speciesinfo/siebenrockiella_crassicollis.htm}} Their powerful jaws are also capable of inflicting wounds if handled roughly.

Black marsh turtles reach sexual maturity at five years. Nesting season occurs in the summer, between April and the end of June. In courtship, males will bob their heads up and down while chasing a female. It may bite the legs of the females several times before mating. Females will lay three or four clutches. Each clutch consisting usually of one or rarely two relatively large eggs, around {{convert|5|by|3|cm|in|abbr=on}} and weighing {{convert|30|g|lb|abbr=on}}.{{cite book|author1=Ernst, Carl H. |author2=Barbour, Roger W. |name-list-style=amp |url=https://books.google.com/books?id=4QbSIQAACAAJ&q=editions:UicWAQAAIAAJ|title =Turtles of the World|publisher =Smithsonian Institution Press|location=Washington D.C. |year = 1989|isbn =978-1-56098-212-8}} The eggs are incubated for 68 to 84 days before hatching. The hatchlings are relatively large, measuring around {{convert|5|cm|in|abbr=on}}.

The maximum known lifespan of black marsh turtles observed in captivity is about 60 years.{{cite journal |author=Rene E. Honegger |date=15 May 1986 |title=Zur Pilege und langjährigen Nachzucht von Siehenrockiella crassicollis (GRAY, 1831) |journal=Salamandra |volume=22 |issue=1 |pages=1–10 |url=https://www.salamandra-journal.com/index.php/home/contents/1986-vol-22/1039-honegger-r-e/file |archive-url=https://web.archive.org/web/20190806171607/https://www.salamandra-journal.com/index.php/home/contents/1986-vol-22/1039-honegger-r-e/file |archive-date=2019-08-06}}

Black marsh turtles are culturally important to Buddhism. In Thailand, large numbers of black marsh turtles, along with the yellow-headed temple turtles (Heosemys annandalii) are released into temple and castle ponds and cared for by Buddhist monks. They are treated as sacred by the public, being believed to contain the souls of people who died while trying to rescue other people from drowning.{{cite web|url=http://www.bristolzoo.org.uk/black-marsh-turtle|title=Black marsh turtle|publisher=Bristol Zoo Gardens|access-date=2 April 2011|archive-url=https://web.archive.org/web/20110314220215/http://www.bristolzoo.org.uk/black-marsh-turtle|archive-date=14 March 2011}}{{cite book|author1=Roth, Harald H. |author2=Merz, Günter |name-list-style=amp |title =Wildlife resources: a global account of economic use|publisher =Springer|year =1997|page=85|url=https://books.google.com/books?id=edro0UWcWn0C|isbn =3-540-61357-9}} One of their commons names, Siamese temple turtle, originated from this practice.

In a study in 2010, black marsh turtles were among the turtles found to contain high levels of mercury in their tissues. Their consumption as food is discouraged as they have the potential to cause mercury poisoning.Green AD, Buhlmann KA, Hagen C, Romanek C, Gibbons JW. (2010)."[http://fiercereptiles.org/Teaching/BIOL2550/Labs/Lab_4/Green%202010%20Hg%20in%20turtles.pdf Mercury contamination in turtles and implications for human health"] {{Webarchive|url=https://web.archive.org/web/20110816041654/http://fiercereptiles.org/Teaching/BIOL2550/Labs/Lab_4/Green%202010%20Hg%20in%20turtles.pdf |date=16 August 2011 }}. J Environ Health 72 (10):14–22. Retrieved 1 April 2011

Black marsh turtles are now being captive bred both for conservation and for the pet trade. In 2004, a black marsh turtle hatched at the Bristol Zoo Gardens. It was the first of its species to successfully hatch in a European zoo.{{cite web|url=http://www.bristolzoo.org.uk/about/news/News1075|title=The first Black Marsh Turtle to hatch in a European zoo|publisher=Bristol Zoo Gardens|access-date=2 April 2011|archive-url=https://web.archive.org/web/20110807155838/http://www.bristolzoo.org.uk/about/news/News1075|archive-date=7 August 2011}} Captive bred black marsh turtles are preferable as pets, being healthier and more acclimated to handling than individuals captured from the wild and illegally exported.

Black marsh turtles are classified as endangered by the International Union for Conservation of Nature. They are also listed on CITES Appendix II.{{cite journal|author1=Gong, Shi-Ping |author2=Chow, Alex T. |author3=Fong, Jonathan J. |author4= Shi, Hai-Tao |year=2009|url=http://www.jonjfong.com/Website/Publications_files/Gong_etal_2009_Oryx.pdf|title= The chelonian trade in the largest pet market in China: scale, scope and impact on turtle conservation|journal=Oryx|volume=43|issue=2|pages=213–216|publisher= Fauna & Flora International|doi=10.1017/S0030605308000902|s2cid=86140967 |access-date= 1 April 2011|doi-access=free}} Aside from signatories to CITES, Black marsh turtles are also specifically protected in Thailand under the Wild Animals Reservation Protection Act (WARPA).{{cite web |year=2004|url=http://www.asianturtlenetwork.org/library/useful_resources/species_lists/thailand_species_list.pdf |archive-url=https://web.archive.org/web/20110928122040/http://www.asianturtlenetwork.org/library/useful_resources/species_lists/thailand_species_list.pdf |archive-date=2011-09-28 |title=Tortoises and Freshwater Turtles of Thailand |website=Asian Turtle Conservation Network|access-date=1 April 2011 }} General laws against the trade and/or capture of freshwater turtles or wildlife that also extend to black marsh turtles are also in place in Myanmar, Singapore, and Vietnam.{{cite journal|author= People's Republic of China and the United States of America |year=2004|url=http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Diesmos_etal_2005.pdf|title=CITES proposal for the Inclusion of Siebenrockiella crassicollis in Appendix II in accordance with Article II 2(a) of the Convention, and satisfying Resolution Conf. 9.24, Annex 2a, Criteria A and Bi).|journal=Consideration of Proposals for Amendment of Appendices I and II |volume=Prop. 12.29|publisher= Convention on International Trade in Endangered Species of Wild Fauna and Flora|access-date=1 April 2011 }}

Despite these sanctions, the greatest threat to black marsh turtles, along with other Southeast Asian freshwater turtles, is the rising demand for turtles for the international meat trade, particularly for the Chinese food markets.{{cite web|url=http://nytts.org/asianturtlecrisis.html|title=The Asian Turtle Crisis: Species Currently Impacted by the Chinese Food Market|author=McCord, William|year=1997|publisher=New York Turtle and Tortoise Society}} Black marsh turtle populations in Cambodia and Vietnam are already considered endangered for this reason. The plastra of black marsh turtles are also among those sought after for traditional Chinese medicine,{{cite book|author1 =Webb, Grahame J.W.|author2 =Manolis, S. Charlie|author3 =Gray, Michelle|title =Captive Breeding and Marketing of Turtles|publisher =Rural Industries Research and Development Corporation, Australian Government|url =https://rirdc.infoservices.com.au/downloads/08-012|year =2008|isbn =978-1-74151-601-2|issn =1440-6845|access-date =2 April 2011|archive-url =https://web.archive.org/web/20110303094507/https://rirdc.infoservices.com.au/downloads/08-012|archive-date =3 March 2011}} particularly for a traditional preparation known as Kuei-Lu-Erh-Hsien-Chiao (KLEHC).{{cite journal|author=Lu, Kang-Tsu|author2=Lo, Chi-Fang|author3=Lin, Jer-huei|name-list-style=amp|year=2009|url=http://www.fda.gov.tw/files/publish_periodical/P001-155.pdf|title=Identification of Testudinis Carapax and Cervi Cornu in Kuei-Lu-Erh-Hsien-Chiao by Nested PCR and DNA Sequencing Methods|journal=Journal of Food and Drug Analysis (藥物食品分析)|volume=17|issue=3|pages=151–155|publisher= Bureau of Food and Drug Analysis, Department of Health, Taiwan}} Thousands of individuals are often confiscated regularly in shipments. Each representing just a small fraction of the actual number of wild turtles being caught and sold in the Asian markets.{{cite journal|author= Hendrie, Douglas|year=2004|url=http://www.asianturtlenetwork.org/library/bulletins/ATCN_bulletin_Oct_04.pdf|title=News from around the Region|journal=The Asian Turtle Crisis Bulletin|volume=1|issue=2|publisher= The Asian Turtle Conservation Network|access-date= 1 April 2011}}

• {{cite web |author1=Kendrick, R.C. |author2=Aides, G.W.J. |name-list-style=amp |year=2009|url=http://www.kfbg.org.hk/content/79/21/2/KFBG_Turtle_Plastron_Study_Report_2006-2009.pdf |archive-url=https://web.archive.org/web/20110720063036/http://www.kfbg.org.hk/content/79/21/2/KFBG_Turtle_Plastron_Study_Report_2006-2009.pdf |archive-date=2011-07-20 |title=Turtle Plastron Study Report 2006-09 |website=Kadoorie Farm and Botanic Garden |access-date= 1 April 2011}}
• {{cite book|author= Schoppe, Sabine|year=2008|url=http://www.trafficj.org/publication/09-Science_in_CITES_Box_Turtle.pdf|title=Science in CITES: The biology and ecology of the Southeast Asian Box Turtle Cuora amboinensis and its local uses and trade in Malaysia|pages=30–31|isbn= 978-983-3393-18-3|publisher= TRAFFIC Southeast Asia, World Wildlife Fund|location=Petaling Jaya, Selangor, Malaysia}}
• {{cite journal|author= Hendrie, Douglas|year=2004|url=http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Diesmos_etal_2005.pdf|title=Turtle Conservation Indochina |journal=Newsletter of the Turtle Conservation and Ecology Program |volume=2|issue=1|publisher= Turtle Conservation and Ecology Program}}
• {{cite journal|author=Le, Minh|year=2007|title=Conservation of turtles in Vietnam: a survey of Cat Tien National Park|journal=Oryx|volume=41|issue=4|pages=544–547|publisher= Conservation Biology of Freshwater Turtles and Tortoises|doi=10.1017/S0030605307012148|s2cid=85990659|url=http://www.seaturtle.org/PDF/Le_2008_Oryx.pdf|doi-access=free}}

Official records in 1999 show that around 135,000 individuals were exported within the span of 10 months in Malaysia alone. In addition to this, black marsh turtles are increasingly being threatened in its native range by habitat loss.

• Siebenrockiella leytensis, the Philippine forest turtle

{{Reflist}}

{{Wikispecies|Siebenrockiella crassicollis}}

{{Commons category|position=left|Siebenrockiella crassicollis}}

• [http://www.asianturtlenetwork.org/index.htm Asian Turtle Conservation Network]
• [http://www.turtlepuddle.org/exotics/crassicollis.html Siebenrockiella crassicollis Care Sheet]

{{Geoemydidae}}

{{Taxonbar |from=Q2180636}}

Category:Siebenrockiella

Category:Turtles of Asia

Category:Reptiles of Southeast Asia

Category:Reptiles described in 1831

Category:Taxa named by John Edward Gray

Turtle, Black marsh

Category:Taxonomy articles created by Polbot

Category:Reptiles of Borneo