Echidna Development: Difference between revisions
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Revision as of 15:04, 21 June 2010
Introduction
The Echidna family consists of 2 major groups the short-beaked in Australia and long-beaked in New Guinea and Indonesia (Irian Jaya). Together with the platypus these are the only 3 surviving genera of the order Monotremata.
![](/embryology/images/thumb/a/a2/Echidna_egg_ultrasound.jpg/300px-Echidna_egg_ultrasound.jpg)
The echidna is a unique egg-laying mammal, the embryo is referred too as a "puggle" (not to be confused with the dog breed, produced by mating a Pug with a Beagle) and is not a common animal model of mammalian embryonic development.
The New Guinea long-beaked echidna (Zaglossus bruijni bartoni) is currently on the endangered category (More? Zoo Threatened Species list)
Some Recent Findings
- Hibernation and reproduction overlap in the echidna. [2] "During hibernation there is a slowing of all metabolic processes, and thus it is normally considered to be incompatible with reproduction. ... The mating of males with torpid females is the result of extreme competition between promiscuous males, while re-entry into hibernation by pregnant females could improve the possibility of mating with a better quality male."
- Characterisation of monotreme caseins [3] "...Overall, the conservation of the genomic organisation of the caseins indicates the early, pre-monotreme development of the fundamental role of caseins during lactation. In contrast, the lineage-specific gene duplications that have occurred within the casein locus of monotremes and eutherians but not marsupials, which may have lost part of the ancestral casein locus, emphasises the independent selection on milk provision strategies to the young, most likely linked to different developmental strategies. The monotremes therefore provide insight into the ancestral drivers for lactation and how these have adapted in different lineages."
- Monotreme olfactory tubercle[4] "... The small olfactory tubercle region in the platypus is consistent with poor olfaction in that aquatic mammal, but the tubercle in the echidna is more like that of a microsmatic mammal than other placentals occupying a similar niche (e.g., insectivores)."
- Sensory trigeminal nuclei of the echidna, platypus and rat.[5] "..... Our findings indicate that the trigeminal nuclei of the echidna do not appear to be highly specialized, but that the principal, oralis and interpolaris subnuclei of the platypus trigeminal complex are highly differentiated, presumably for processing of tactile and electrosensory information from the bill."
Taxon
Short-beaked Echidna - Tachyglossus aculeatus
Long-beaked Echidna - Zaglossus bruijni
Tachyglossus aculeatus Lineage (full) cellular organisms; Eukaryota; Fungi/Metazoa group; Metazoa; Eumetazoa; Bilateria; Coelomata; Deuterostomia; Chordata; Craniata; Vertebrata; Gnathostomata; Teleostomi; Euteleostomi; Sarcopterygii; Tetrapoda; Amniota; Mammalia; Prototheria; Monotremata; Tachyglossidae; Tachyglossus
Echidna Zaglossus bruijn Lineage (full) cellular organisms; Eukaryota; Fungi/Metazoa group; Metazoa; Eumetazoa; Bilateria; Coelomata; Deuterostomia; Chordata; Craniata; Vertebrata; Gnathostomata; Teleostomi; Euteleostomi; Sarcopterygii; Tetrapoda; Amniota; Mammalia; Prototheria; Monotremata; Tachyglossidae
Development Overview
Gestation is from 22 to 23 days. (based upon 20 observed matings and documenting 30 incidences of egg laying, Rismiller, 1999).
Egg only a single egg is generally laid.
Incubation lasts for approximately 10 days after laying, the hatched embryo (puggle) requires further development.
Embryo after hatching hangs from hairs and succles from a "mammary gland" (mammary hairs) in the pouch for approximately 50 days and continues to develop.
Evolution
The oldest platypus and its bearing on divergence timing of the platypus and echidna clades. Rowe T, Rich TH, Vickers-Rich P, Springer M, Woodburne MO. Proc Natl Acad Sci U S A. 2008 Jan 29;105(4):1238-42. Epub 2008 Jan 23. PMID: 18216270
- "Monotremes have left a poor fossil record, and paleontology has been virtually mute during two decades of discussion about molecular clock estimates of the timing of divergence between the platypus and echidna clades. ...Strict molecular clock estimates of the divergence between platypus and echidnas range from 17 to 80 Ma, but Teinolophos (Early Cretaceous fossil) suggests that the two monotreme clades were already distinct in the Early Cretaceous, and that their divergence may predate even the oldest strict molecular estimates by at least 50%."
WWW Links
Pelican Lagoon Research & Wildlife Centre Echidna Research
International Union for Conservation of Nature and Natural Resources Red List | Zaglossus bruijni Australasian Marsupial & Monotreme Specialist Group 1996. Zaglossus bruijni. In: IUCN 2004. 2004 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 13 February 2006.
The Australian Mammal Society Species Short-beaked Echidna | Long-beaked Echidna
Access Excellence The National Health Museum (USA) Australian Mammals: Evolutionary Development as a Result of Geographic Isolation
Science Alert CRCA Media Release 05/29 Echidna milk to reveal its secrets for dairy
Wombaroo Food Products Echidna Milk Replacer
Note: The dynamic nature of the web means that some Links over time change, it the above links no longer function search the web using the first bold term.
References
Reviews
<pubmed>14667851</pubmed> <pubmed>14667856</pubmed> <pubmed>14667846</pubmed> <pubmed>11999298</pubmed>
Articles
<pubmed>16435291</pubmed> <pubmed>16244467</pubmed> <pubmed>2048749</pubmed> <pubmed>8103529</pubmed> <pubmed>12476054</pubmed>
Books
The Echidna: Australia's Enigma (Hardcover, 1999), by Peggy Rismiller (Amazon Link) "The oldest surviving mammal on the planet is also one of the most intriguing. Peggy Rismiller, the world's foremost echidna expert, traces the history of this fascinating animal that is native to Australia and New Guinea. A combination of mammal, reptile, and marsupial, echidnas produce milk, but unlike mammals, they are egg-laying creatures and, like marsupials, they have a modified pouch for nurturing their young. This odd animal has two backward-facing appendages and two forward-facing ones. These and other bizarre biological traits are discussed in detail in this thorough guide. Amazing photographs of echidnas enliven Rismiller's text, which includes Aboriginal tribal legends about the animal as well as the latest information on biological research being conducted today. With fossils dating back 120 million years, the echidna lived alongside dinosaurs, but unlike the giant reptiles, it survived. Its story and biology teach a fascinating lesson about endurance, survival, and sustainability."
American Museum Novitates (American Museum of Natural History) Van Deusen, H. M., and G. G. George. Results of the Archbold Expeditions. No. 90. Notes on the echidnas (Mammalia: Tachyglossidae) of New Guinea. American Museum Novitates, 2383:1-23 (1969)
Search PubMed
Search Jan2006 "Echidna development" 303 reference articles of which 20 were reviews.
Search PubMed: Echidna development | monotreme development
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Cite this page: Hill, M.A. (2024, May 25) Embryology Echidna Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Echidna_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G