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Egg-laying mammals (monotremes) are considered "primitive" due to traits such as oviparity, cloaca, and incomplete homeothermy, all of which they share with reptiles. Two groups of monotremes, the terrestrial echidna (Tachyglossidae) and semiaquatic platypus (Ornithorhynchidae), have evolved highly divergent characters since their emergence in the Cenozoic era. These evolutionary differences, notably including distinct electrosensory and chemosensory systems, result from adaptations to species-specific habitat conditions. To date, very few studies have examined the visual adaptation of echidna and platypus. In the present study, we show that echidna and platypus have different light absorption spectra in their dichromatic visual sensory systems at the molecular level. We analyzed absorption spectra of monotreme color opsins, long-wavelength sensitive opsin (LWS) and short-wavelength sensitive opsin 2 (SWS2). The wavelength of maximum absorbance (λmax) in LWS was 570.2 in short-beaked echidna (Tachyglossus aculeatus) and 560.6 nm in platypus (Ornithorhynchus anatinus); in SWS2, λmax was 451.7 and 442.6 nm, respectively. Thus, the spectral range in echidna color vision is ~ 10 nm longer overall than in platypus. Natural selection analysis showed that the molecular evolution of monotreme color opsins is generally functionally conserved, suggesting that these taxa rely on species-specific color vision. In order to understand the usage of color vision in monotremes, we made 24-h behavioral observations of captive echidnas at warm temperatures and analyzed the resultant ethograms. Echidnas showed cathemeral activity and various behavioral repertoires such as feeding, traveling, digging, and self-grooming without light/dark environment selectivity. Halting (careful) behavior is more frequent in dark conditions, which suggests that echidnas may be more dependent on vision during the day and olfaction at night. Color vision functions have contributed to dynamic adaptations and dramatic ecological changes during the ~ 60 million years of divergent monotreme evolution. The ethogram of various day and night behaviors in captive echidnas also contributes information relevant to habitat conservation and animal welfare in this iconic species, which is locally endangered. [ABSTRACT FROM AUTHOR]

The short‐beaked echidna is sexually monomorphic such that gender identification without veterinary intervention is challenging. The aim of this study was to evaluate and compare the most optimal noninvasive genetic source by extracting echidna genomic DNA (gDNA) from fecal scats, plucked hair, and quills to perform genetic sex testing using a range of molecular markers. Sex determination of 14 captive short‐beaked echidnas was determined by amplifying isolated DNA from noninvasive samples, targeting two Y chromosome (male‐specific) genes (mediator complex subunit 26 Y‐gametologue [CRSPY] and anti‐Müllerian hormone Y‐gametologue [AMHY]), in addition to four confirmed sex‐specific RADseq markers. Results of noninvasive samples were compared with blood samples and clinical records. Receiver operating characteristic curves were used to assess accuracy of sex determination of markers for each sample type. The gender of the echidnas was successfully identified on 75% of occasions using fecal samples, 90.6% occasions using hair, and 84.6% occasions with quills. Overall, the male‐specific RADseq markers accurately identified the sex of echidnas with all sample types for 90% of animals; compared with 81.5% using CRSPY, and 82.0% using AMHY to identify sex. Collection of hair, quills, and feces provides a useful alternative to invasively collected samples, however, the accuracy of results depends on sample type and genetic marker selected. We found gender determination in the short‐beaked echidna was most accurate using four male‐specific RADseq markers on gDNA isolated from blood and hair. The noninvasive genetic sexing techniques documented here will inform and facilitate husbandry and genetic management of captive echidna populations. Research highlights: Noninvasive genetic sampling provides potential for sex determination in animal species that lack easily identifiable sexually dimorphic characteristics such as the short‐beaked echidna.This manuscript presents new information on the efficiency of gender identification using DNA isolated from noninvasive samples, including hair, quills, and feces; amplified with a suite of male‐specific genetic markers, and includes assessment of sex identification accuracy of genetic markers for each sample type. [ABSTRACT FROM AUTHOR]

After observing a fight between two snowflake eels in southern Taiwan, we had difficulties locating scientific information on eel–eel aggressive behaviour and looked further afield. We collected and scored 34 videos posted on social media, to provide more insight into antagonistic behaviours in eels. The videos showed 12 different species of moray eels involved in aggressive interactions, with the genus Gymnothorax contributing to ~ 71% and Echidna contributing to 24% of the observed occurrences. 82% of the videos documented antagonistic interactions between conspecifics. The fights involved "knotting", when opponents curl around each other and shove with their bodies, and some biting. Overall, the incidence of injury and death of losers, as well as injury of winners, was higher in smaller-bodied opponents. Conspecific encounters elicited the greatest intensity of aggressive behaviour, which we interpreted as rivalry due to dominance hierarchies and territoriality. This normally included a visible resource the opponents fought over (a den, a food item, a mate). Same-species fights started after gaping mouths at each other, with individuals being roughly equal in size. Conspecific opponents were often injured, but never killed. Available videos with fights between different species included predatory attacks and defensive reactions. Except for one case, interspecific encounters often ended with one eel being killed and eaten, with the winner being a fish-eating Gymnothorax species. Pre-fight, the killer was observed displaying food searching behaviour by checking holes. Both conspecific and interspecific fights frequently incurred deep, V-shaped wounds that were not apparently life threatening. Old V-shaped scars occurred on the bodies of some eels. Such scars could be used in research further investigating aggressive behaviour in moray eels. [ABSTRACT FROM AUTHOR]

Abstract Indigenous gut microbial communities (microbiota) play critical roles in health and may be especially important for the mother and fetus during pregnancy. Monotremes, such as the short‐beaked echidna, have evolved to lay and incubate an egg, which hatches in their pouch where the young feeds. Since both feces and eggs pass through the cloaca, the fecal microbiota of female echidnas provides an opportunity for vertical transmission of microbes to their offspring. Here, we characterize the gut/fecal microbiome of female short‐beaked echidnas and gain a better understanding of the changes that may occur in their microbiome as they go through pregnancy. Fecal samples from four female and five male echidnas were obtained from the Currumbin Wildlife Sanctuary in Queensland and sequenced to evaluate bacterial community structure. We identified 25 core bacteria, most of which were present in male and female samples. Genera such as Fusobacterium, Bacteroides, Escherichia‐Shigella, and Lactobacillus were consistently abundant, regardless of sex or gestation stage, accounting for 58.00% and 56.14% of reads in male and female samples, respectively. The echidna microbiome remained stable across the different gestation stages, though there was a significant difference in microbiota composition between male and female echidnas. This study is the first to describe the microbiome composition of short‐beaked echidnas across reproductive phases and allows the opportunity for this novel information to be used as a metric of health to aid in the detection of diseases triggered by microbiota dysbiosis.

The echidna (Tachyglossus aculeatus) is documented as a new native predator of freshwater turtle eggs, particularly those of the vulnerable Fitzroy River turtle (Rheodytes leukops), and the critically endangered white-throated snapping turtle (Elseya albagula). This depredation has been identified in the Fitzroy, Burnett and Mary Catchments with echidnas recorded at traditional turtle nesting banks using direct observation of depredation of eggs, remote camera footage and identification of tracks. Echidnas were observed at traditional nesting banks for E. albagula and R. leukops nesting across eight months of the year. The presence of echidnas was more frequent during the R. leukops nesting season in spring. R. leukops is endemic to the Fitzroy Catchment and the depredation rate of eggs was significantly higher than for other species and catchments. The mean top egg depth of R. leukops nests was found to be the same depth as the echidna's beak length. There was a significant increase in depredation during the five-year study period, with 47.4% of R. leukops clutches depredated by echidna in the 2022 season. This substantial loss of eggs and recruitment of hatchling turtles poses a significant threat to the populations of this threatened species. The short-beaked echidna (Tachyglossus aculeatus) has been found to be an unlikely predator of freshwater turtle eggs. Egg depredation of the vulnerable Fitzroy River turtle (Rheodytes leukops) and the critically endangered white-throated snapping turtle (Elseya albagula) was recorded during annual freshwater turtle nesting surveys. The egg depredation by the echidna has been recorded across the Fitzroy, Burnett and Mary Catchments. Photograph by Duncan Limpus. [ABSTRACT FROM AUTHOR]

Horizontal transfer of transposable elements (TEs) is an important mechanism contributing to genetic diversity and innovation. Bats (order Chiroptera) have repeatedly been shown to experience horizontal transfer of TEs at what appears to be a high rate compared with other mammals. We investigated the occurrence of horizontally transferred (HT) DNA transposons involving bats. We found over 200 putative HT elements within bats; 16 transposons were shared across distantly related mammalian clades, and 2 other elements were shared with a fish and two lizard species. Our results indicate that bats are a hotspot for horizontal transfer of DNA transposons. These events broadly coincide with the diversification of several bat clades, supporting the hypothesis that DNA transposon invasions have contributed to genetic diversification of bats. [ABSTRACT FROM AUTHOR]

The most striking feature of monotremes is that they are egg-laying mammals, but this was only accepted by the scientific establishment eight decades after specimens of echidna and platypus were first examined in Europe. Even before the specimens were sent, colonists had been told by Indigenous Australians that the echidna and platypus laid eggs. In this paper I briefly summarise aspects of the significance of monotremes in some mainland Aboriginal cultures, and the attempts by the naturalist George Bennett to discover if platypuses were oviparous. In Tasmania the disruption of Aboriginal culture early in the 19th century meant that there are very few details known of their insights into ecosystems and monotreme biology. Some incidental information was recorded by George Augustus Robinson during his "Friendly Mission", while what appears to be a previously unremarked presentation at the Royal Society of Van Diemen's Land in 1849 reveals Aboriginal knowledge of the reproductive behaviour and life history of Tasmanian echidnas not described in the scientific literature until very recently. [ABSTRACT FROM AUTHOR]

This paper argues that Lycophron's Alexandra follows earlier texts in presenting challenges to Agamemnon's power as metaphorical re-enactments of primordial theogonic conflicts between Zeus and the forces of chaos. The Alexandra figures Agamemnon as Zeus and portrays Achilles, Clytemnestra and Cassandra as chthonic monsters opposed to the Olympian order. Employing intertexts with epic and tragedy, the poem highlights these figures' symbolic antagonism with Agamemnon–Zeus and their connections to each other. It presents a radically resystematized vision of the cosmos that champions the chthonic, the disordered and the feminine over the Olympian, the ordered and the masculine. Cassandra uses this backdrop to reinterpret her own story, inserting herself into the cosmogonic narrative as a resister of Olympian patriarchy who triumphs over masculine domination. [ABSTRACT FROM AUTHOR]

Long-beaked echidnas (Zaglossus spp.) have received less attention in the literature than Short-beaked echidnas (Tachyglossus aculeatus). Their natural history, anatomy, and physiology are poorly known. To improve our understanding of this unique group, we undertook a radiographic study of the Eastern long-beaked echidna (Zaglossus bartoni), and provide a comparative analysis of its radiographic skeletal anatomy with that of T. aculeatus. We examine conventional radiography and computed tomographic images of Zaglossus and Tachyglossus, describe the anatomical features of Zaglossus, and compare those with Tachyglossus. We provide evidence of epicoracoid overlap in echidnas, a feature not well documented in monotremes. The significance of epicoracoid overlap requires further investigation. Our study is intended as a reference for the radiographic anatomy of Z. bartoni. [ABSTRACT FROM AUTHOR]

Monotremes (echidnas and platypus) possess five X and four or five Y sex chromosomes, respectively, that evolved independently from the sex chromosomes found in therian mammals. While the platypus has obvious venomous spurs in the male, the short-beaked echidna (Tachyglossus aculeatus) lacks easily identifiable sexually dimorphic characteristics, making it difficult to sex adults out of the breeding season and almost impossible to sex juveniles or embryonic material. Here, we used restriction-site associated DNA sequencing (RADseq) to identify novel sex-specific markers in the short-beaked echidna. We identified and validated a subset of male-specific markers that can be used as a non-invasive genetic sex test for the short-beaked echidna. We also assessed how laboratory conditions, including DNA extraction protocol and number of PCR cycles, can influence the outcome of genetic sex tests. The combined use of these markers will provide a valuable toolkit for researchers, conservationists, and zoo-keepers to reliably and non-invasively determine sex in the short-beaked echidna. [ABSTRACT FROM AUTHOR]

Egg-laying mammals (monotremes) are a sister clade of therians (placental mammals and marsupials) and a key clade to understand mammalian evolution. They are classified into platypus and echidna, which exhibit distinct ecological features such as habitats and diet. Chemosensory genes, which encode sensory receptors for taste and smell, are believed to adapt to the individual habitats and diet of each mammal. In this study, we focused on the molecular evolution of bitter taste receptors (TAS2Rs) in monotremes. The sense of bitter taste is important to detect potentially harmful substances. We comprehensively surveyed agonists of all TAS2Rs in platypus (Ornithorhynchus anatinus) and short-beaked echidna (Tachyglossus aculeatus) and compared their functions with orthologous TAS2Rs of marsupial and placental mammals (i.e. therians). As results, the agonist screening revealed that the deorphanized monotreme receptors were functionally diversified. Platypus TAS2Rs had broader receptive ranges of agonists than those of echidna TAS2Rs. While platypus consumes a variety of aquatic invertebrates, echidna mainly consumes subterranean social insects (ants and termites) as well as other invertebrates. This result indicates that receptive ranges of TAS2Rs could be associated with feeding habits in monotremes. Furthermore, some orthologous receptors in monotremes and therians responded to β-glucosides, which are feeding deterrents in plants and insects. These results suggest that the ability to detect β-glucosides and other substances might be shared and ancestral among mammals. [ABSTRACT FROM AUTHOR]

Successful breeding of short-beaked echidnas (Tachyglossus aculeatus acanthion) occurred at Perth Zoo on eight occasions between 2007 and 2012. Here we report the methods used for monitoring and managing breeding females and their young from hatching through to weaning. Growth and development of the young during burrow-life was quantified through regular weighing and maternal care was monitored using video camera surveillance. All young hatched between early August and mid-September and were deposited in nursery burrows in October–November at 58–63 days of age at an average mass of 295 ± 64.3 g. Mothers suckled their young, on average, every 3.3 ± 1.1 days. Young first emerged from their nursery burrow from mid-January into February at an average 169 ± 21 days of age and weighing 1674 ± 511 g, and reached 3 kg in mass at 348 ± 97 days of age. Sexual maturity of two female offspring was attained at 4 years of age. Our observations of maternal care and development of the captive-bred young are consistent with published observations made on wild echidnas. We suggest that important factors for the successful rearing of captive-bred echidnas are enclosure set-up, daily monitoring, combined with a suitably designed and managed nursery burrow that provides a suitable substrate and microenvironment. Eight short-beaked echidnas were successfully bred and reared to independence at Perth Zoo between 2007 and 2012. Detailed information was gathered on the development of the young during nursery burrow life and weaning through to 2 years of age, filling important knowledge gaps in this species. Our study provides insights to support the rearing of orphaned wild echidnas for rehabilitation as well as a foundation of knowledge to support development of similar important wildlife breeding programs. Photograph by Arthur Ferguson. [ABSTRACT FROM AUTHOR]

Introduction: A new species of the nematode genus Parastrongyloides Morgan, 1928 was found in the caecum of six short-beaked echidnas Tachyglossus aculeatus (Shaw, 1792) collected from southwestern Australia between August 1964 and March 2020. Methods: Specimens were prepared for microscopic examination as temporary wet mounts, measurements were made using an Olympus DP71 camera with cellSens standard software, figures were drawn using a drawing tube and light micrographs taken. DNA was extracted using a Qiagen blood and tissue kit, amplified targeting the COX1 gene region. Sequences obtained were analysed and edited using Geneious v.8.1 and aligned to existing sequences published in Genbank using MUSCLE. Results: Parastrongyloides spratti n. sp. can be distinguished from all other species of Parastrongyloides in having the male caudal papillae arranged as a single median dome-shaped pre-cloacal papilla, three tiny pairs of ventral papillae immediately pre-cloacal, a tiny ventral pair of papillae post-cloacal and the female with four to five pairs of dorsoventral papillae immediately anterior to the vulva. A revised key to the species of Parastrongyloides found in Australia is given. Sequence analysis of the COX1 gene corroborated the species status of P. spratti. Discussion: Morphological and molecular analyses support the status of P. spratti as a new species. Parastrongyloides may have an ancient origin in the Australian portion of Gondwanaland. [ABSTRACT FROM AUTHOR]

The heterogeneity of resource distribution in arid environments plays an important role in habitat selection by consumers. The productivity of the riparian zones of intermittently flowing creeks is typically prolonged, relative to the hinterland, as moisture and nutrients concentrate there. Short-beaked echidnas, Tachyglossus aculeatus , sustain arid populations, attributed to ant and termite availability, low predation, and an ability to exploit habitat remnants. However, the scale of their movements in arid habitats is poorly understood. Thus, we investigated echidna home ranges and the importance of food and shelter availability in habitat selection over one winter. We focussed on the riparian zone of a creek at Mount Wood in Sturt National Park, north-western New South Wales, Australia. Radio tracking (VHF and GPS), scat and habitat selection analyses were conducted. Mean core and peripheral home range areas were 0.16 and 1.042 km2, respectively, with a mean home range overlap of 0.56 km2. Habitat selection differed between juveniles and adults and may have been driven by prey availability (predominantly ants). The preferred shelter was thick leaf litter. We concluded that habitat selection patterns were driven by prey availability (ants) and shelter (leaf litter). Riparian zones are the resource-rich areas surrounding creeks, rivers, and other waterways, which are particularly important in arid environments where resources are low. Echidnas are found throughout Australia, including resource-poor, arid environments, and this paper investigated echidna movements and habitat selection in relation to arid riparian zones and resource availability. Habitat use differed by age, and habitats were not selected in proportion to availability. Habitat selection was driven by prey (ants) and shelter availability. [ABSTRACT FROM AUTHOR]

Echidnas are commonly known as 'spiny ant-eaters', but long-beaked echidnas (Zaglossus spp.) do not eat ants, whereas short-beaked echidnas (Tachyglossus aculeatus) eat other invertebrates as well as ants. The differences in skull morphology between short- and long-beaked echidnas are related to the differences in their diets, and I tested the hypothesis that there would be differences in beak length of short-beaked echidnas from populations with different diets. Published data on diet from echidnas from different parts of Australia show that echidnas from arid and semi-arid areas (subspecies acanthion) and Kangaroo Island (subspecies multiaculeatus) principally eat ants and termites, whereas the main dietary items of echidnas from south-eastern Australia (subspecies aculeatus) and Tasmania (subspecies setosus) are ants and scarab larvae. Using museum specimens and photographs I measured skull dimensions on echidnas from different parts of Australia: acanthion and multiaculeatus have narrower skulls and shorter beaks than aculeatus and setosus , with setosus being the only Australian subspecies where beak length exceeds cranium length. Australian short-beaked echidnas fall into two groups: aculeatus and setosus from the wetter east and south-east, which eat ant and scarab larvae, and the arid and semi-arid zone acanthion and multiaculeatus , with shorter, narrower skulls, and which eat ants and termites. Echidnas occur all over Australia, but echidnas from different regions vary greatly in the length of the spines and hair. This paper shows there are also big differences in beak length. Tasmanian echidnas have the longest beaks, whereas arid zone echidnas have very short beaks. Beak length is related to diet and feeding behaviour: longer beaks are better suited to probing for scarab larvae, while short beaks are better for ploughing through the soil for ants and termites. Diet, beak length and claw lengths divide Australian echidnas into two groups. [ABSTRACT FROM AUTHOR]

Botryomycosis is a chronic bacterial infection of the skin and viscera caused by nonbranching bacteria such as Staphylococcus spp. It results in the formation of chronic, suppurative and often granulomatous lesions that may resemble multiple abscesses. It has been diagnosed worldwide in both humans and animals. It is a rare disease, usually requiring surgical excision combined with long‐term antibiotics to achieve a good resolution. A wild echidna (Tachyglossus aculeatus) was presented with a soft tissue mass at the base of the right distal beak with multiple discharging fistulas arising from it. The mandible appeared to be shortened and deviated to the right, and the animal was unable to close its beak. The echidna was in poor body condition and was euthanased on welfare grounds. Histopathology of the lesions demonstrated the classical botryoid lesions with the characteristic Splendore‐Hoeppli reaction surrounding the bacterial colonies, in a background of extensive granulation tissue. Radiographs revealed mild mandibular osteomyelitis, yet haematology and biochemistry results were nonspecific. This disease has not previously been reported in a wild monotreme. [ABSTRACT FROM AUTHOR]

Monotremes diverged from therian mammal ancestors approximately 184 million years ago and have a number of novel reproductive characteristics. One in particular is their penile morphology. There are differences between echidna and platypus phalluses, but both are somewhat similar in structure to the reptilian phallus. The echidna penis consists of 4 rosette glans, each of which contains a termination of the quadrifurcate urethra, but it appears that only 2 of the 4 glans become erect at any one time. Despite this, only a few historical references describe the structure of the echidna penis and none provides an explanation for the mechanisms of unilateral ejaculation. This study confirmed that the echidna penis contains many of the same overall structures and morphology as other mammalian penises and a number of features homologous with reptiles. The corpus cavernosum is well supplied with blood, extends up to the base of the glans penis and is primarily responsible for erection. However, the echidna possesses 2 distinct corpora spongiosa separated by a septum, each of which surround the urethra only distal to the initial urethral bifurcation in the glans penis. Together with the bifurcation of the main penile artery, this provides a mechanism by which blood flow could be directed to only one corpus spongiosum at a time to maintain an open urethra that supplies 2 of the 4 glans to facilitate unilateral ejaculation. [ABSTRACT FROM AUTHOR]

Short-beaked echidna (Tachyglossus aculeatus) are a cryptic and iconic monotreme found throughout the continent of Australia. Despite observational records spanning many years aggregated in national and state biodiversity databases, the spatial and temporal intensity of sightings is limited. Although the species is of least conservation concern at the global level, a subspecies has been declared endangered on Kangaroo Island in South Australia. We need better population data over the whole continent to inform this species’ conservation management. To increase the temporal and spatial resolution of observations which may be used for more accurate population assessments, we developed a mobile app for citizen scientists to easily record echidna sightings and improve the quantity, quality and distribution of data collected for monitoring this species. EchidnaCSI is a free, cross-platform (Android & iOS), open-source app that we developed to collect echidna observational data around Australia. EchidnaCSI has been in use since September 2017 and uses mobile phone sensors to transparently and automatically record metadata, such as species observation location and time and GPS location precision. We examine differences in spatial coverage between these observations and those in existing data repositories in the Atlas of Living Australia and state biodiversity databases, especially in relation to observations in protected areas and to an index of remoteness and accessibility. EchidnaCSI has contributed over 8000 echidna observations from around Australia, more than recorded in all state systems combined, with similar spatial distribution. Although coverage was more limited in some protected areas than the reference data sources, numbers of observations in all remote areas were greater than the reference scientific data except for very remote regions. EchidnaCSI has improved the spatial and temporal intensity of observations for this iconic species and provides a complement to scientific surveys, which might usefully focus on highly protected areas and very remote regions.

Introduction: Nematodes were found in the digestive tracts of 15 short-beaked echidnas Tachyglossus aculeatus (Shaw, 1792) collected from southwestern Australia between August 1964 and March 2020. Methods: Specimens were prepared for microscopic examination as temporary wet mounts, measurements were made, figures prepared using a drawing tube and light micrographs taken. All nematodes were identified to at least genus level and a bootstrap analysis of the helminth community was carried out. Results: Two previously described species, one species identified to genus and one new nematode species were recovered, including Nicollina ridei (Nicollinidae), Parapharyngodon anomalus (Pharyngodonidae), Parastrongyloides sp. (Strongyloididae) and Echidnonema coronorum n. g., n. sp. (Subuluridae, Echidnonematinae n. sf.). Echidnonema coronorum n. sp. can be distinguished from all other subulurids in having a mouth encircled by six leaf-like elements separated by six small pointed elements. The buccal complex is also unique to this species and is composed of three parts, including an anterior buccal capsule and a posterior pharyngeal portion divided into two; the proximal part contains lobes which are ornamented with numerous irregular teeth. A bootstrap estimate of species richness of 99.9% indicated that there were few, if any, additional species to be discovered in the southwestern Australian population of short-beaked echidnas. Conclusion: Morphological analysis supports the status of E. coronorum as a new species and the erection of the Echidnonematinae as a new subfamily to accommodate it. The helminth community of the population of short-beaked echidnas studied appears to be depauperate and contains species unique to the region. [ABSTRACT FROM AUTHOR]

Bioturbation by digging animals is important for key forest ecosystem processes such as soil turnover, decomposition, nutrient cycling, water infiltration, seedling recruitment, and fungal dispersal. Despite their widespread geographic range, little is known about the role of the short-beaked echidna (Tachyglossus aculeatus) in forest ecosystems. We measured the density and size of echidna diggings in the Northern Jarrah Forest, south-western Australia, to quantify the contribution echidna make to soil turnover. We recorded an overall density of 298 echidna diggings per hectare, 21% of which were estimated to be less than 1 month old. The average size of digs was 50 ± 25 mm in depth and 160 ± 61 mm in length. After taking into account seasonal digging rates, we estimated that echidnas turn over 1.23 tonnes of soil ha−1 year−1 in this forest, representing an important role in ecosystem dynamics. Our work contributes to the growing body of evidence quantifying the role of these digging animals as critical ecosystem engineers. Given that the echidna is the only Australian digging mammal not severely impacted by population decline or range reduction, its functional contribution to health and resilience of forest ecosystems is increasingly important due to the functional loss of most Australian digging mammals. Bioturbation represents an important ecological process within Australian ecosystems. We measured the size and density of echidna diggings in the northern jarrah forest in south-west Western Australia. Taking seasonal changes into account, we estimated echidnas collectively turn over 1.23 tonnes of soil ha−1 year−1 in this forest. Echidnas are one of the only remaining digging animals in Australia not severely impacted by population decline and their contribution to the health and resilience of forest ecosystems is likely to become increasingly important. Photograph by S. Dundas. [ABSTRACT FROM AUTHOR]

Flavonoids are a major group of plant-specific metabolites that determine flower and seed coloration. In plant cells, flavonoids are synthesized at the cytosolic surface of the endoplasmic reticulum and are sequestered in the vacuole. It is possible that membrane trafficking, including vesicle trafficking and organelle dynamics, contributes to flavonoid transport and accumulation. However, the underlying mechanism has yet to be fully elucidated. Here we show that the Arabidopsis ECHIDNA protein plays a role in flavonoid accumulation in the vacuole and protein trafficking to the vacuole. We found defective pigmentation patterns in echidna seed, possibly caused by reduced levels of proanthocyanidins, which determine seed coloration. The echidna mutant has defects in protein sorting to the protein storage vacuole as well as vacuole morphology. These findings indicate that ECHIDNA is involved in the vacuolar trafficking pathway as well as the previously described secretory pathway. In addition, we found a genetic interaction between echidna and green fluorescent seed 9 (gfs9), a membrane trafficking factor involved in flavonoid accumulation. Our findings suggest that vacuolar trafficking and/or vacuolar development, both of which are collectively regulated by ECHIDNA and GFS9, are required for flavonoid accumulation, resulting in seed coat pigmentation. [ABSTRACT FROM AUTHOR]

Most biologists, particularly Australian biologists, are aware that the initial description and attempts to classify the echidna and platypus were surrounded by controversy. Fewer are aware of the important roles played by two eminent scientists, Étienne Geoffroy Saint-Hilaire in Paris and Richard Owen in London, in the debate as to whether the platypus and echidna were really mammals, and whether they laid eggs. Geoffroy argued that they were egg-laying but could not possibly lactate; Owen argued that they lactated but could not possibly lay eggs. Because of these and many other aspects of their biology, monotremes featured prominently in debates about classification of animals and the transmutation of species, and involved many important scientists of the time. These arguments can only be understood in the context of the development of science in the late eighteenth and the nineteenth century, and how that was influenced by the social context. Early ideas of evolution, or transformism, were attractive to radical thinkers, whereas social conservatives were anxious to show that the boundaries between types of animals, just like the boundaries between social classes, were erected by God and could not be crossed. [ABSTRACT FROM AUTHOR]

EchAMP, the tenth most abundant transcript expressed in the mammary gland of echidna, has in vitro broad-spectrum antibacterial effects. However, the effects of EchAMP on mastitis, a condition where inflammation is triggered following mammary gland infection, has not been investigated. To investigate the impact of EchAMP against mastitis, EchAMP transgenic mice were generated. In antibacterial assays, the whey fractions of milk from transgenic mice significantly reduced growth of Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa compared with whey fractions from wildtype mice. Furthermore, a mastitis model created by infecting mammary gland with these four bacterial strains displayed a significant reduction in bacterial load in transgenic mice injected with S. aureus and B. subtilis. On further confirmation, histomorphologic analysis showed absence of necrosis and cell infiltration in the mammary glands of transgenic mice. To understand the role of EchAMP against inflammation, we employed an LPS-injected mastitis mouse model. LPS is known to induce phopshorylation of NF-κB and MAPK pathways, which in turn activate downstream proinflammatory signaling mediators, to promote inflammation. In LPS-treated EchAMP transgenic mice, phosphorylation levels of NF-κB, p38 and ERK1/2 were significantly downregulated. Furthermore, in mammary gland of transgenic mice, there was a significant downregulation of mRNA levels of proinflammatory cytokines, namely TNF-α, IL-6 and IL-1β. Taken together, these data suggest that EchAMP has an antiinflammatory response and is effective against S. aureus and B. subtilis. We suggest that EchAMP may be a potential prophylactic protein against mastitis in dairy animals by expressing this gene in their mammary gland. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Antibiotic resistance is a problem that necessitates the identification of new antimicrobial molecules. Milk is known to have molecules with antimicrobial properties (AMPs). Echidna Antimicrobial Protein (EchAMP) is one such lactation specific AMP exclusively found in the milk of Echidna, an egg-laying mammal geographically restricted to Australia and New Guinea. Previous studies established that EchAMP exhibits substantial bacteriostatic activity against multiple bacterial genera. However, the subsequent structural and functional studies were hindered due to the unavailability of pure protein. In this study, we expressed EchAMP protein using a heterologous expression system and successfully purified it to >95% homogeneity. The purified recombinant protein exhibits bacteriolytic activity against both Gram-positive and Gram-negative bacteria as confirmed by live-dead staining and scanning electron microscopy. Structurally, this AMP belongs to the family of intrinsically disordered proteins (IDPs) as deciphered by the circular-dichroism, tryptophan fluorescence, and NMR spectroscopy. Nonetheless, EchAMP has the propensity to acquire structure with amphipathic molecules, or membrane mimics like SDS, lipopolysaccharides, and liposomes as again observed through multiple spectroscopic techniques. Recombinant EchAMP exhibits broad-spectrum bacteriolytic activity by compromising the bacterial cell membrane integrity. Hence, we propose that this intrinsically disordered antimicrobial protein interact with the bacterial cell membrane and undergoes conformational changes to form channels in the membrane resulting in cell lysis. EchAMP, the evolutionarily conserved, lactation specific AMP from an oviparous mammal may find application as a broad-spectrum antimicrobial against pathogens that affect mammary gland or otherwise cause routine infections in humans and livestock. Unlabelled Image • Echidna milk protein, EchAMP was purified from the recombinant bacterial source • An intrinsically disordered protein with a broad-spectrum bacteriolytic activity • Transitions to alpha-helical conformation upon bacterial membrane interaction • Helical form causes bacterial membrane disruption, cytosol leakage, and cell death [ABSTRACT FROM AUTHOR]

• Monotremes have a lower cortical white matter volume compared to therians. • This suggests fewer cortical association fibres in monotremes compared to therians. • Cortical white matter is shifted caudally in the platypus and long-beaked echidna. • Forebrain structure in monotremes suggests convergence with myrmecophagous xenarthrans. We have made quantitative volumetric analyses of cerebral cortical (pallial) structures in the brains of three species of monotreme (Ornithorhynchus anatinus , Tachyglossus aculeatus , Zaglossus bruijni) and compared the findings with similar measurements in a range of therian mammals (6 marsupials and 50 placentals). We have found that although the iso- and periallocortical grey matter volume of the monotremes is about what would be expected for their brain size, the proportion of iso- and periallocortical white matter in monotremes is substantially lower than that in the forebrains of therians. This suggests that the forebrains of the three monotremes have fewer association, commissural and/or projection connections than those of similarly sized forebrains of therian mammals. We also found that the iso- and periallocortex of the platypus is relatively smooth-surfaced compared to similarly sized brains of therian mammals, with a distinct caudal shift in the positioning of cortical white matter in the forebrain, consistent with expansion of the posterior thalamic radiation. Central laminated olfactory structures (anterior olfactory nucleus and piriform cortex) are large in the tachyglossid monotremes (Tachyglossus aculeatus and Zaglossus bruijni) and large in xenarthran placental mammals, suggesting convergence of the forebrain structure of monotreme formivores with that of similarly specialized therians like the xenarthrans Myrmecophaga tridactyla and Dasypus novemcinctus. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In 1803, the French anatomist Étienne Geoffroy Saint-Hilaire decided that the newly described echidna and platypus should be placed in a separate order, the monotremes, intermediate between reptiles and mammals. The first physiological observations showed monotremes had low body temperatures and metabolic rates, and the consensus was that they were at a stage of physiological development intermediate between “higher mammals” and “lower vertebrates.” Subsequent studies demonstrated that platypuses and echidnas are capable of close thermoregulation in the cold although less so under hot conditions. Because the short-beaked echidna Tachyglossus aculeatus, may show very large daily variations in body temperature, as well as seasonal hibernation, it has been suggested that it may provide a useful model of protoendotherm physiology. Such analysis is complicated by the very significant differences in thermal relations between echidnas from different climates. In all areas female echidnas regulate Tb within 1°C during egg incubation. The lactation period is considered to be the most energetically expensive time for most female mammals but lactating echidnas showed no measurable difference in field metabolic rate from non-lactating females, while the lactation period is more than 200 days for Kangaroo Island echidnas but only 150 days in Tasmania. In areas with mild winters echidnas show reduced activity and shallow torpor in autumn and early winter, but in areas with cold winters echidnas enter true hibernation with Tb falling as low as 4.5°C. Monotremes do not possess brown adipose tissue and maximum rates of rewarming from hibernation in echidnas were only half those of marmots of the same mass. Although echidnas show very large seasonal variations in fat stores associated with hibernation there is no relationship between plasma leptin and adiposity. Leptin levels are lowest during post-reproductive fattening, supporting suggestions that in evolutionary terms the anorectic effects of leptin preceded the adiposity signal. BMR of platypuses is twice that of echidnas although maximum metabolism is similar. High levels of thyroid hormones in platypuses may be driving metabolism limited by low body temperature. Monotremes show a mosaic of plesiomorphic and derived features but can still inform our understanding of the evolution of endothermy.

The monotremes (platypuses and echidnas) represent one of only four extant venomous mammalian lineages. Until recently, monotreme venom was poorly understood. However, the availability of the platypus genome and increasingly sophisticated genomic tools has allowed us to characterize platypus toxins, and provides a means of reconstructing the evolutionary history of monotreme venom. Here we review the physiology of platypus and echidna crural (venom) systems as well as pharmacological and genomic studies of monotreme toxins. Further, we synthesize current ideas about the evolution of the venom system, which in the platypus is likely to have been retained from a venomous ancestor, whilst being lost in the echidnas. We also outline several research directions and outstanding questions that would be productive to address in future research. An improved characterization of mammalian venoms will not only yield new toxins with potential therapeutic uses, but will also aid in our understanding of the way that this unusual trait evolves.

In 1803, the French anatomist Étienne Geoffroy Saint-Hilaire decided that the newly described echidna and platypus should be placed in a separate order, the monotremes, intermediate between reptiles andmammals. The first physiological observations showed monotremes had low body temperatures and metabolic rates, and the consensus was that they were at a stage of physiological development intermediate between "higher mammals" and "lower vertebrates." Subsequent studies demonstrated that platypuses and echidnas are capable of close thermoregulation in the cold although less so under hot conditions. Because the short-beaked echidna Tachyglossus aculeatus, may show very large daily variations in body temperature, as well as seasonal hibernation, it has been suggested that it may provide a useful model of protoendotherm physiology. Such analysis is complicated by the very significant differences in thermal relations between echidnas from different climates. In all areas female echidnas regulate Tb within 1°C during egg incubation. The lactation period is considered to be the most energetically expensive time for most female mammals but lactating echidnas showed no measurable difference in field metabolic rate from non-lactating females, while the lactation period is more than 200 days for Kangaroo Island echidnas but only 150 days in Tasmania. In areas with mild winters echidnas show reduced activity and shallow torpor in autumn and early winter, but in areas with cold winters echidnas enter true hibernation with Tb falling as low as 4.5°C. Monotremes do not possess brown adipose tissue and maximum rates of rewarming from hibernation in echidnas were only half those of marmots of the same mass. Although echidnas show very large seasonal variations in fat stores associated with hibernation there is no relationship between plasma leptin and adiposity. Leptin levels are lowest during post-reproductive fattening, supporting suggestions that in evolutionary terms the anorectic effects of leptin preceded the adiposity signal. BMR of platypuses is twice that of echidnas although maximum metabolism is similar. High levels of thyroid hormones in platypuses may be driving metabolism limited by low body temperature. Monotremes show a mosaic of plesiomorphic and derived features but can still inform our understanding of the evolution of endothermy. [ABSTRACT FROM AUTHOR]

Endocrine regulation of milk protein gene expression in marsupials and eutherians is well studied. However, the evolution of this complex regulation that began with monotremes is unknown. Monotremes represent the oldest lineage of extant mammals and the endocrine regulation of lactation in these mammals has not been investigated. Here we characterised the proximal promoter and hormonal regulation of two platypus milk protein genes, Beta-lactoglobulin ( BLG ), a whey protein and monotreme lactation protein ( MLP ), a monotreme specific milk protein, using in vitro reporter assays and a bovine mammary epithelial cell line (BME-UV1). Insulin and dexamethasone alone provided partial induction of MLP , while the combination of insulin, dexamethasone and prolactin was required for maximal induction. Partial induction of BLG was achieved by insulin, dexamethasone and prolactin alone, with maximal induction using all three hormones. Platypus MLP and BLG core promoter regions comprised transcription factor binding sites (e.g. STAT5, NF-1 and C/EBPα) that were conserved in marsupial and eutherian lineages that regulate caseins and whey protein gene expression. Our analysis suggests that insulin, dexamethasone and/or prolactin alone can regulate the platypus MLP and BLG gene expression, unlike those of therian lineage. The induction of platypus milk protein genes by lactogenic hormones suggests they originated before the divergence of marsupial and eutherians. [ABSTRACT FROM AUTHOR]

The word numphè occurs four times only in the Theogony. Nymphs are first mentioned as mountain inhabitants, then Hesiod tells us about the birth of the Melian Nymphs on occasion of Ouranos’s castration. Lastly, the term numphè is, surprisingly enough, twice applied to the monstrous Echidna. The naiads are not referred to but the Oceanids, though not described as numphai, seem to fulfill some of their functions. Creatures of intermediary status, the Nymphs appear as powers mediating between the divine and the human sphere ; finally they seem to have a scanty place in a primarily theogonic statement, which notably explains how men separated themselves from the gods.

The motor neurons in the spinal cord of an echidna ( Tachyglossus aculeatus) have been mapped in Nissl-stained sections from spinal cord segments defined by spinal nerve anatomy. A medial motor column of motor neurons is found at all spinal cord levels, and a hypaxial column is found at most levels. The organization of the motor neuron clusters in the lateral motor column of the brachial (C5 to T3) and crural (L2 to S3) limb enlargements is very similar to the pattern previously revealed by retrograde tracing in placental mammals, and the motor neuron clusters have been tentatively identified according to the muscle groups they are likely to supply. The region separating the two limb enlargements (T4 to L1) contains preganglionic motor neurons that appear to represent the spinal sympathetic outflow. Immediately caudal to the crural limb enlargement is a short column of preganglionic motor neurons (S3 to S4), which it is believed represents the pelvic parasympathetic outflow. The rostral and caudal ends of the spinal cord contain neither a lateral motor column nor a preganglionic column. Branchial motor neurons (which are believed to supply the sternomastoid and trapezius muscles) are present at the lateral margin of the ventral horn in rostral cervical segments (C2-C4). These same segments contain the phrenic nucleus, which belongs to the hypaxial column. The presence or absence of the main spinal motor neuron columns in the different regions echidna spinal cord (and also in that of other amniote vertebrates) provides a basis for dividing the spinal cord into six main regions - prebrachial, brachial, postbrachial, crural, postcrural and caudal. The considerable biological and functional significance of this subdivision pattern is supported by recent studies on spinal cord hox gene expression in chicks and mice. On the other hand, the familiar 'segments' of the spinal cord are defined only by the anatomy of adjacent vertebrae, and are not demarcated by intrinsic gene expression. The recognition of segments defined by vertebrae (somites) is obviously of great value in defining topography, but the emphasis on such segments obscures the underlying evolutionary reality of a spinal cord comprised of six genetically defined regions. The six-region system can be usefully applied to the spinal cord of any amniote (and probably most anurans), independent of the number of vertebral segments in each part of the spinal column. [ABSTRACT FROM AUTHOR]

Background: To date, little has been documented about microorganisms harboured within Australian native ticks or their pathogenic potential. Recently, a Borrelia sp. related to the Relapsing Fever (RF) group was identified in a single tick removed from a wild echidna (Tachyglossus aculeatus). The present study investigated the presence of Borrelia in 97 Bothriocroton concolor ticks parasitizing echidnas in Queensland, New South Wales, and Victoria, Australia, using nested PCR with Borrelia-specific primers targeting the 16S rRNA (16S) and flaB genes. Results: Borrelia-specific PCR assays confirmed the presence of a novel Borrelia sp. related to the RF and reptile-associated (REP) spirochaetes in 38 (39 %) B. concolor ticks. This novel Borrelia sp. was identified in 41 % of the B. concolor ticks in Queensland and New South Wales, but not in any ticks from Victoria. The resulting flaB sequences (407 bp) were 88 and 86 % similar to the flaB sequences from Borrelia turcica and Borrelia hermsii, respectively. Of the ticks confirmed as Borrelia-positive following the flaB assay, 28 were positive with the 16S assay. Phylogenetic analysis of the 16S sequences (1097 bp) suggests that these sequences belong to a novel Borrelia sp., which forms a unique monophyletic clade that is similar to, but distinct from, RF Borrelia spp. and REP-associated Borrelia spp. Conclusions: We conclude that the novel Borrelia sp. identified in this study does not belong to the Borrelia burgdorferi (sensu lato) complex, and that the phylogenetic analysis of the partial 16S gene sequences suggests it forms a unique monophyletic cluster in the genus Borrelia, potentially forming a fourth major group in this genus associated with monotremes in Australia. However, a thorough molecular characterisation will be required to confirm the phylogenetic position of this unique Borrelia sp. The zoonotic potential and pathogenic consequences of this novel Borrelia sp. are unknown at the current time. [ABSTRACT FROM AUTHOR]

The short-beaked echidna Tachyglossus aculeatus is a seasonally breeding mammal with a near ubiquitous distribution throughout Australia. In Tasmania, breeding follows a period of deep hibernation, and males begin mating approximately 30 days after the termination of hibernation. The echidna has exceptionally large testes, which may reach a maximum of 1% of body mass during the mating period. As involution of gonads is considered a prerequisite for entering hibernation and hibernation typically suppresses all reproductive function, this raises questions about the timing of testes recrudescence in the Tasmanian echidna. We measured plasma testosterone concentrations and used ultrasonography to measure testicular and crural gland volume through the annual cycle in wild Tasmanian echidnas. Testes were at their minimum size (0.06% of body mass) in December (early summer); testes recrudescence occurred prior to entry into hibernation when plasma testosterone concentrations were low; and testes were maintained at 75% of their maximum volume throughout the hibernation period. The crural glands, which are secondary reproductive structures in the echidna, also exhibited an annual pattern of recrudescence and involution, with recrudescence occurring after males emerged from hibernation, when plasma testosterone was rising. We suggest that the unusual strategy of testes recrudescence occurring prior to hibernation in the Tasmanian echidna is a consequence of extremely high competition between males. [ABSTRACT FROM AUTHOR]

A quantitative comparison of the internal diameters of cerebral feeder arteries (internal carotid and vertebral) and the aorta in developing non-human eutherians, metatherians and monotremes has been made, with the aim of determining if there are differences in cerebral arterial flow between the three infraclasses of mammals such as might reflect differences in metabolism of the developing brain. There were no significant differences between eutherians and metatherians in the internal radius of the aorta or the thickness of the aortic wall, but aortic internal radius was significantly smaller in developing monotremes than therians at the < 10 mm body length range. Aortic thickness in the developing monotremes also rose at a slower rate relative to body length than in metatherians or eutherians. The sums of the internal calibres of the internal carotid and vertebral arteries were significantly lower in metatherians as a group and monotremes compared with non-human eutherians at body lengths up to 20 mm and in metatherians at > 20 mm body length. The internal calibre of the internal carotids relative to the sum of all cerebral feeder arteries was also significantly lower in monotremes at < 10 mm body length compared with eutherians. It was noted that dasyurids differed from other metatherians in several measures of cerebral arterial calibre and aortic internal calibre. The findings suggest that: (i) both aortic outflow and cerebral arterial inflow may be lower in developing monotremes than in therians, particularly at small body size (< 20 mm); (ii) cerebral inflow may be lower in some developing metatherians than non-human eutherians; and (iii) dasyurids have unusual features of cerebral arteries possibly related to the extreme immaturity and small size at which they are born. The findings have implications for nutritional sourcing of the developing brain in the three infraclasses of mammals. [ABSTRACT FROM AUTHOR]