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Fenelon JC, Bennetts A, Anthwal N, Pyne M, Johnston SD, Evans AR, Tucker AS, Renfree MB. Getting out of a mammalian egg: the egg tooth and caruncle of the echidna. Dev Biol 2023; 495:8-18. [PMID: 36565838 DOI: 10.1016/j.ydbio.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 12/16/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
In the echidna, after development in utero, the egg is laid in the pouch and incubated for 10 days. During this time, the fetuses develop an egg tooth and caruncle to help them hatch. Using rare and unprecedented access to limited echidna pre- and post-hatching tissues, development of the egg tooth and caruncle were assessed by micro-CT, histology and immunofluorescence. Unlike therian tooth germs that develop by placode invagination, the echidna egg tooth developed by evagination, similar to the first teeth in some reptiles and fish. The egg tooth ankylosed to the premaxilla, rather than forming a tooth root with ligamentous attachment found in other mammals, with loss of the egg tooth associated with high levels of activity odontoclasts and apoptosis. The caruncle formed as a separate mineralisation from the adjacent nasal capsule, and as observed in birds and turtles, the nasal region epithelium on top of the nose expressed markers of cornification. Together, this highlights that the monotreme egg tooth shares many similarities with typical reptilian teeth, suggesting that this tooth has been conserved from a common ancestor of mammals and reptiles.
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Affiliation(s)
- Jane C Fenelon
- School of BioSciences, The University of Melbourne, Victoria, 3010, Australia.
| | - Abbie Bennetts
- School of BioSciences, The University of Melbourne, Victoria, 3010, Australia
| | - Neal Anthwal
- Centre for Craniofacial and Regenerative Biology, King's College London, London, SE1 9RT, UK
| | - Michael Pyne
- Currumbin Wildlife Sanctuary, Currumbin, Queensland, 4223, Australia
| | - Stephen D Johnston
- School of Agriculture and Food Sciences, The University of Queensland, Gatton, 4343, Australia
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia; Geosciences, Museums Victoria, Melbourne, Victoria, 3001, Australia
| | - Abigail S Tucker
- Centre for Craniofacial and Regenerative Biology, King's College London, London, SE1 9RT, UK
| | - Marilyn B Renfree
- School of BioSciences, The University of Melbourne, Victoria, 3010, Australia
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2
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Dutton-Regester KJ, Roser A, Meer H, Russell FA, Pyne M, Renfree MB, Johnston SD, Keeley T. Investigating the utility of using fecal hormone metabolites as a reproductive management tool for captive short-beaked echidnas (Tachyglossus aculeatus). Gen Comp Endocrinol 2023; 330:114142. [PMID: 36243057 DOI: 10.1016/j.ygcen.2022.114142] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/21/2022] [Accepted: 10/09/2022] [Indexed: 11/06/2022]
Abstract
This study demonstrates the utility of the analysis of fecal hormone metabolites as a reproductive management tool for captive short-beaked echidnas. Over three breeding seasons daily fecal samples were collected from female echidnas (n = 8) that were monitored continuously by video surveillance to confirm key reproductive events. Fecal progesterone metabolite concentrations were elevated above baseline values (448.0 ± 156.3 ng/g) during pregnancy and the luteal phase. However, compared to plasma progesterone the rise in fecal progesterone metabolite concentrations after copulation was delayed (3.3 ± 0.4 versus 8.3 ± 0.6 days, respectively), such that pregnancy was more reliably detected in its latter half when using fecal samples. Mating and oviposition were observed for 14 of the 19 pregnancies resulting in an estimated gestation of 16.7 ± 0.2 days (range 16.0-18.1 d). The estrogen enzyme-immunoassays tested (n = 3) in this study were not suitable for the fecal samples of the echidna. Fecal progesterone metabolites are an effective tool for confirming the timing and occurrence of estrous cycles in captive echidna colonies and can assist zookeepers in identifying possible causes of sub-optimal reproductive success without the unnecessary stress of repeated capture and anaesthesia for blood collection.
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Affiliation(s)
- Kate J Dutton-Regester
- School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, Australia.
| | - Alice Roser
- Currumbin Wildlife Sanctuary, Currumbin, Queensland 4223, Australia
| | - Haley Meer
- Currumbin Wildlife Sanctuary, Currumbin, Queensland 4223, Australia
| | - Freya A Russell
- School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, Australia
| | - Michael Pyne
- Currumbin Wildlife Sanctuary, Currumbin, Queensland 4223, Australia
| | - Marilyn B Renfree
- School of BioSciences, The University of Melbourne, Victoria 3010, Australia
| | - Stephen D Johnston
- School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, Australia
| | - Tamara Keeley
- School of Agriculture and Food Sciences, The University of Queensland, Gatton 4343, Australia
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3
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Perry T, West E, Eisenhofer R, Stenhouse A, Wilson I, Laming B, Rismiller P, Shaw M, Grützner F. Characterising the Gut Microbiomes in Wild and Captive Short-Beaked Echidnas Reveals Diet-Associated Changes. Front Microbiol 2022; 13:687115. [PMID: 35847103 PMCID: PMC9279566 DOI: 10.3389/fmicb.2022.687115] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/16/2022] [Indexed: 12/23/2022] Open
Abstract
The gut microbiome plays a vital role in health and wellbeing of animals, and an increasing number of studies are investigating microbiome changes in wild and managed populations to improve conservation and welfare. The short-beaked echidna (Tachyglossus aculeatus) is an iconic Australian species, the most widespread native mammal, and commonly held in zoos. Echidnas are cryptic animals, and much is still unknown about many aspects of their biology. Furthermore, some wild echidna populations are under threat, while echidnas held in captivity can have severe gastric health problems. Here, we used citizen science and zoos to collect echidna scats from across Australia to perform the largest gut microbiome study on any native Australian animal. Using 16S rRNA gene metabarcoding of scat samples, we characterised and compared the gut microbiomes of echidnas in wild (n = 159) and managed (n = 44) populations, which were fed four different diets. Wild echidna samples were highly variable, yet commonly dominated by soil and plant-fermenting bacteria, while echidnas in captivity were dominated by gut commensals and plant-fermenting bacteria, suggesting plant matter may play a significant role in echidna diet. This work demonstrates significant differences between zoo held and wild echidnas, as well as managed animals on different diets, revealing that diet is important in shaping the gut microbiomes in echidnas. This first analysis of echidna gut microbiome highlights extensive microbial diversity in wild echidnas and changes in microbiome composition in managed populations. This is a first step towards using microbiome analysis to better understand diet, gastrointestinal biology, and improve management in these iconic animals.
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Affiliation(s)
- Tahlia Perry
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
- Centre of Excellence for Australian Biodiversity and Heritage, The University of Adelaide, Adelaide, SA, Australia
| | - Ella West
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Raphael Eisenhofer
- Centre of Excellence for Australian Biodiversity and Heritage, The University of Adelaide, Adelaide, SA, Australia
| | - Alan Stenhouse
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Isabella Wilson
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | | | - Peggy Rismiller
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
- Pelican Lagoon Research and Wildlife Centre, Penneshaw, SA, Australia
| | - Michelle Shaw
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
- Taronga Wildlife Nutrition Centre, Taronga Conservation Society Australia, Mosman, NSW, Australia
| | - Frank Grützner
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
- Centre of Excellence for Australian Biodiversity and Heritage, The University of Adelaide, Adelaide, SA, Australia
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4
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Abstract
Abstract
Tachyglossus aculeatus (Shaw, 1792) is a monotreme commonly called the short-beaked echidna. Although considered Australia’s most common native mammal because of its continent-wide distribution, its population numbers everywhere are low. It is easily distinguished from all other native Australian mammals because of its spine-covered body, hairless beak, and unique “rolling” gait. The five subspecies, one of which is found in Papua New Guinea, show variations in fur density, spine diameter, length, and number of grooming claws. The Kangaroo Island short-beaked echidna Tachyglossus aculeatus multiaculeatus is listed as “Endangered” but all other Tachyglossus are listed as “Least Concern” in the 2016 International Union for Conservation of Nature and Natural Resources Red List.
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Affiliation(s)
- Peggy D Rismiller
- Pelican Lagoon Research & Wildlife Centre, Penneshaw, South Australia, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Frank Grutzner
- The Environment Institute, The University of Adelaide, Adelaide, South Australia, Australia
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5
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Perry T, Toledo-Flores D, Kang WX, Ferguson A, Laming B, Tsend-Ayush E, Lim SL, Grützner F. Non-invasive genetic sexing technique for analysis of short-beaked echidna (Tachyglossus aculeatus) populations. Reprod Fertil Dev 2019; 31:1289-1295. [PMID: 31158328 DOI: 10.1071/rd18142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 05/04/2019] [Indexed: 11/23/2022] Open
Abstract
Identifying male and female echidnas is challenging due to the lack of external genitalia or any other differing morphological features. This limits studies of wild populations and is a major problem for echidna captive management and breeding. Non-invasive genetic approaches to determine sex minimise the need for handling animals and are used extensively in other mammals. However, currently available approaches cannot be applied to monotremes because their sex chromosomes share no homology with sex chromosomes in other mammals. In this study we used recently identified X and Y chromosome-specific sequences to establish a non-invasive polymerase chain reaction-based technique to determine the sex of echidnas. Genomic DNA was extracted from echidna hair follicles followed by amplification of two Y chromosome (male-specific) genes (mediator complex subunit 26 Y-gametolog (CRSPY) and anti-Müllerian hormone Y-gametolog (AMHY)) and the X chromosome gene (anti-Müllerian hormone X-gametolog (AMHX)). Using this technique, we identified the sex of 10 juvenile echidnas born at Perth Zoo, revealing that eight of the 10 echidnas were female. Future use of the genetic sexing technique in echidnas will inform captive management, continue breeding success and can be used to investigate sex ratios and population dynamics in wild populations.
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Affiliation(s)
- Tahlia Perry
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Deborah Toledo-Flores
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Wan X Kang
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Arthur Ferguson
- Perth Zoo, 20 Labouchere Road, South Perth, WA 6151, Australia
| | - Belinda Laming
- Perth Zoo, 20 Labouchere Road, South Perth, WA 6151, Australia
| | - Enkhjargal Tsend-Ayush
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Shu L Lim
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Frank Grützner
- The Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia; and Corresponding author.
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6
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Summerell AE, Frankham GJ, Gunn P, Johnson RN. DNA based method for determining source country of the short beaked echidna (Tachyglossus aculeatus) in the illegal wildlife trade. Forensic Sci Int 2018; 295:46-53. [PMID: 30554021 DOI: 10.1016/j.forsciint.2018.11.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 11/06/2018] [Accepted: 11/20/2018] [Indexed: 11/25/2022]
Abstract
The illegal trade in wild animals being sold as 'captive bred' is an emerging issue in the pet and zoo industry and has both animal welfare and conservation implications. DNA based methods can be a quick, inexpensive, and definitive way to determine the source of these animals, thereby assisting efforts to combat this trade. The short beaked echidna (Tachyglossus aculeatus) is currently one of the species suspected to be targeted in this trade. As this species is distributed throughout Australia and in New Guinea (currently comprising of five recognised sub-species), this project aimed to develop a DNA based method to definitively determine the source country of an echidna and explore the use of non-invasive sampling techniques. Here we use non-invasively sampled echidna quills and demonstrate the extraction of mitochondrial DNA and amplification of a region of the mitochondrial genome. Phylogenetically informative markers for analysis of a 322bp segment of the D-loop region were developed, and subsequently validated, using animals with known source locations allowing us to reliably distinguish between echidnas from New Guinea, and Australia. This research presents the first validated forensic protocols for short beaked echidnas and will be an integral tool in understanding the movement of animals in this emerging trade.
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Affiliation(s)
- A E Summerell
- Australian Centre for Wildlife Genomics, Australian Museum Research Institute, 1 William Street, Sydney, Australia; Centre for Forensic Science, University of Technology Sydney, 15 Broadway, Ultimo, Australia.
| | - G J Frankham
- Australian Centre for Wildlife Genomics, Australian Museum Research Institute, 1 William Street, Sydney, Australia
| | - P Gunn
- Centre for Forensic Science, University of Technology Sydney, 15 Broadway, Ultimo, Australia
| | - R N Johnson
- Australian Centre for Wildlife Genomics, Australian Museum Research Institute, 1 William Street, Sydney, Australia.
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Wallage A, Clarke L, Thomas L, Pyne M, Beard L, Ferguson A, Lisle A, Johnston S. Advances in the captive breeding and reproductive biology of the short-beaked echidna (Tachyglossus aculeatus). AUST J ZOOL 2015. [DOI: 10.1071/zo14069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Captive breeding of the short-beaked echidna (Tachyglossus aculeatus) has proven a difficult challenge; as recently as 2009, there were fewer than 10 echidnas born in captivity. We present observations of captive reproductive behaviour following video surveillance and measurements of body temperature collected from six captive female echidnas over a six-year period. In the first series of observations (2009–10) we examined the efficacy of artificial burrow boxes as possible aids for reproductive success. Females with access to burrow boxes had significantly higher levels of reproductive activity (P = 0.001), there was coincidental improvement in the production of eggs or pouch young (two eggs, one unhatched and one offspring). During 2009–10, a range of reproductive behaviours (courtship, copulation and postcopulation) were documented and analysed, as were new observations of oestrous cycle activity. Female body temperature was characteristically stable during egg incubation during this study and has the potential to be used as a tool for the assessment of reproductive status. Following initial observations, burrow boxes and infrared lamps were implemented as standard husbandry in our echidna breeding facility and the effects on reproductive success were monitored, albeit less intensively, for a further four years (2011–14). Although no direct causal effect could be ascribed, the use of burrow boxes and heat lamps coincided with a total of 13 young being born to four females in the last four years (2011–14). These female echidnas were found to be receptive at intervals throughout the breeding season, both before and after presumed incubation phases, suggesting that captive animals exhibit polyoestry. In 2012 and 2014, the same female showed evidence of producing two young from one breeding event.
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Harris RL, Nicol SC. Observations of breeding behaviour and possible infanticide in a wild population of Tasmanian echidnas (Tachyglossus aculeatus setosus). AUSTRALIAN MAMMALOGY 2014. [DOI: 10.1071/am13011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We describe field observations of Tasmanian echidna behaviour, including possible infanticide, where males damaged and entered nursery burrows. We also present the second report of a female producing a second offspring within a single reproductive season after the loss of her first young at an early stage.
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