|Embryology - 25 Apr 2018 Expand to Translate|
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The koala (Phascolarctos cinereus) is an arboreal herbivorous marsupial native to Australia, and the only extant representative of the family Phascolarctidae.
(Greek, phaskolos = "pouch" and arktos = "bear"; Latin, cinereus = "ash-coloured")
Koala comes from the Dharuk gula, the word is erroneously said to mean "doesn't drink"
|Australian Animal: echidna | kangaroo | koala | platypus | possum | Category:Echidna | Category:Kangaroo | Category:Koala | Category:Platypus | Category:Possum | Category:Marsupial | Category:Monotreme | Development Timetable | K12|
Some Recent Findings
|More recent papers|
This table shows an automated computer PubMed search using the listed sub-heading term.
References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.
Elleke Cremers, Carel Thijs, John Penders, Eugene Jansen, Monique Mommers Maternal and child's vitamin D supplement use and vitamin D level in relation to childhood lung function: the KOALA Birth Cohort Study. Thorax: 2011, 66(6);474-80 PubMed 21422038
Kentaro Katayama, Sayaka Miyamoto, Aki Furuno, Kouyou Akiyama, Sakino Takahashi, Hiroetsu Suzuki, Takehito Tsuji, Tetsuo Kunieda Characterization of the chromosomal inversion associated with the Koa mutation in the mouse revealed the cause of skeletal abnormalities. BMC Genet.: 2009, 10;60 PubMed 19772620
Geoffrey W Pye Shoulder dysplasia in koalas (Phascolarctos cinereus) at San Diego Zoo. J. Zoo Wildl. Med.: 2009, 40(3);453-7 PubMed 19746859
Katherine A Fantauzzo, Marija Tadin-Strapps, Yun You, Sarah E Mentzer, Friedrich A M Baumeister, Stefano Cianfarani, Lionel Van Maldergem, Dorothy Warburton, John P Sundberg, Angela M Christiano A position effect on TRPS1 is associated with Ambras syndrome in humans and the Koala phenotype in mice. Hum. Mol. Genet.: 2008, 17(22);3539-51 PubMed 18713754
A Gifford, G Fry, B A Houlden, T P Fletcher, E M Deane Gestational length in the koala, Phascolarctos cinereus. Anim. Reprod. Sci.: 2002, 70(3-4);261-6 PubMed 11943495
Taxonomy ID: 38626
Genbank common name: koala Inherited blast name: marsupials
Genetic code: Translation table 1 (Standard)
Mitochondrial genetic code: Translation table 2 (Vertebrate Mitochondrial)
Lineage ( full ) cellular organisms; Eukaryota; Fungi/Metazoa group; Metazoa; Eumetazoa; Bilateria; Coelomata; Deuterostomia; Chordata; Craniata; Vertebrata; Gnathostomata; Teleostomi; Euteleostomi; Sarcopterygii; Tetrapoda; Amniota; Mammalia; Theria; Metatheria; Diprotodontia; Phascolarctidae; Phascolarctos
- Adults - females reach maturity at 2 to 3 years of age, males at about 3 years of age.
- Joey - a single young produced each year for about 12 years.
- Gestation - approximately 35 days, born under-developed (hairless, blind, and earless). There is a report of extended gestation.
- Birth - joey about 6 mm long crawls into the the mother's downward-facing pouch.
- Pouch Development - joey remain in the pouch for about 6 months attached to one of the two available teats and feeding on milk, complete development.
- Outside of the pouch - joey then begins to explore and to consume small quantities of the mother’s "pap" (thought to come from the mother's cecum) in order to inoculate its gut with the microbes necessary to digest eucalypt leaves.
- Joey will remain with its mother for about another 6 months, riding on her back, and feeding on both milk and eucalypt leaves until weaning is complete at about 12 months of age.
The marsupial neonate at birth has a variation between the degree of development of different systems.
- well-developed - digestive, respiratory and circulatory system.
- not well-developed - retains fetal excretory system with a fully functional mesonephric kidney and undifferentiated gonads and genitalia.
Ovarian Follicle Development
The following data is from a histological study of ovaries from adult female koalas.
- primordial follicles - have a small primary oocyte surrounded by a few squamous epithelial cells
- primary follicles - have a single layer of cuboidal granulosa cells around the oocyte.
- secondary follicles - have two or more layers of granulosa cells but no antrum
- tertiary follicles (Graafian) - have many layers of granulosa cells surrounding a follicular fluid-filled antrum of variable size.
- oocytes about 140 µm in diameter (range 110–162 µm: n = 5 individuals) surrounded by a zona pellucida (ZP) about 8 µm thick, which is twice as thick as most other marsupial species.
Marsupial eggs are enclosed by a series of layers:
- zona pellucida, three zona proteins (ZPA, ZPB, ZPC)
- an additional extracellular matrix coat that lines the zona pellucida also occurs in some species.
- mucoid coat
- outer shell coat.
- Links: Oocyte Development
The spermatozoa head is hook-shaped with the most of the acrosomal contents lying within a nuclear concavity. Spermatozoa nuclei show a range of morphologies and a tendency to swell after cryopreservation procedures.
- Links: Spermatozoa Development
- Katrina M Morris, Denis O'Meally, Thiri Zaw, Xiaomin Song, Amber Gillett, Mark P Molloy, Adam Polkinghorne, Katherine Belov Characterisation of the immune compounds in koala milk using a combined transcriptomic and proteomic approach. Sci Rep: 2016, 6;35011 PubMed 27713568
- Anna L Keyte, Kathleen K Smith Developmental origins of precocial forelimbs in marsupial neonates. Development: 2010, 137(24);4283-94 PubMed 21098569
- E F Hynes, K A Handasyde, Geoff Shaw, Marilyn B Renfree Levonorgestrel, not etonogestrel, provides contraception in free-ranging koalas. Reprod. Fertil. Dev.: 2010, 22(6);913-9 PubMed 20591325
- John C Rodger, Damien B B P Paris, Natasha A Czarny, Merrilee S Harris, Frank C Molinia, David A Taggart, Camryn D Allen, Stephen D Johnston Artificial insemination in marsupials. Theriogenology: 2009, 71(1);176-89 PubMed 18950846
- C Esson, P J Armati Development of the male urogenital system of the koala phascolarctos cinereus. Anat. Embryol.: 1998, 197(3);217-27 PubMed 9543340
- A Gifford, G Fry, B A Houlden, T P Fletcher, E M Deane Gestational length in the koala, Phascolarctos cinereus. Anim. Reprod. Sci.: 2002, 70(3-4);261-6 PubMed 11943495
- M B Renfree, A J Pask, G Shaw Sex down under: the differentiation of sexual dimorphisms during marsupial development. Reprod. Fertil. Dev.: 2001, 13(7-8);679-90 PubMed 11999321
- Jamie A Chapman, Christopher M Leigh, William G Breed The zona pellucida of the koala (Phascolarctos cinereus): its morphogenesis and thickness. J. Anat.: 2006, 209(3);393-400 PubMed 16928207
- L Selwood Marsupial egg and embryo coats. Cells Tissues Organs (Print): 2000, 166(2);208-19 PubMed 10729728
- Stephen D Johnston, Carmen López-Fernández, Altea Gosálbez, Yengpeng Zee, William V Holt, Camryn Allen, Jaime Gosálvez The relationship between sperm morphology and chromatin integrity in the koala (Phascolarctos cinereus) as assessed by the Sperm Chromatin Dispersion test (SCDt). J. Androl.: 2007, 28(6);891-9 PubMed 17609294
Stephen D Johnston, William V Holt The Koala (Phascolarctos cinereus): A Case Study in the Development of Reproductive Technology in a Marsupial. Adv. Exp. Med. Biol.: 2014, 753;171-203 PubMed 25091911
M B Renfree Diapause, pregnancy, and parturition in Australian marsupials. J. Exp. Zool.: 1993, 266(5);450-62 PubMed 8371091
Jamie A Chapman, Christopher M Leigh, William G Breed The zona pellucida of the koala (Phascolarctos cinereus): its morphogenesis and thickness. J. Anat.: 2006, 209(3);393-400 PubMed 16928207
T I Grand, P S Barboza Anatomy and development of the koala, Phascolarctos cinereus: an evolutionary perspective on the superfamily Vombatoidea. Anat. Embryol.: 2001, 203(3);211-23 PubMed 11303907
Note searches using the term "Koala" will also find papers that refer to the KOALA Birth Cohort Study, a European study not related to the Australian animal.
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Cite this page: Hill, M.A. (2018, April 25) Embryology Koala Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Koala_Development
- © Dr Mark Hill 2018, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G