Beddomeia camensis is a species of very small freshwater snail that is endemic[2] to Australia. The invertebrate is 2-4 mm in size, it is a gastropodmollusk and belongs to the Hydrobiidae family, a large family of freshwater snails recognised by their small size and cosmopolitan distribution.[3] Beddomeia camensis is one of the least populated species within its family distributed across only 5 small to medium-sized streams that flow into the Cam River catchment in North-West Tasmania.
Due to its minute declining population, Beddomeia camensis is listed as endangered under the Threatened Species Act 1995 and vulnerable under the IUCN Red List.[3] The population has struggled historically due to its limited fecundity and specific habitat requirements which, in turn, have limited the species ability to disperse into new habitats and establish a growing population. Furthermore, in more recent years, the negative impacts of agricultural clearing, forestry, mining and impoundment construction have further impended on the population of the endangered species.[3]
Classification
Family Tree of Beddomeia Camensis
Beddomeia Camensis is a gastropod, belonging to the Prosobranchia subclass, Caenogastropoda order, Truncatelloidea superfamily and the Hydrobiidae family, a family of freshwater snails that consists of over 100 genera.[2] The Hydrobiid is one of the largest families belonging to the truncatelloidea superfamily of small sized aquatic snails, containing an extensive fossil record dating back to the Early Carboniferous.[4]Hydrobiid species can be found all over the world, making their distribution cosmopolitan.[3] Hydrobiids are distributed worldwide most notably in southern parts of Europe, Africa, America and New Zealand.[4] Australia alone is inhabited by 200 species from this family, populating most densely in South Eastern parts of the country.[5][6] The habitual distribution of species varies between estuarine mudflats, mangroves, mountain lakes, caves, creeks, rivers and subterranean groundwater.[4]
Taking a broader look at classification, Beddomeia camensis belongs to the Class Gastropod, comprising over 65,000 species, making it the largest within the phylum Molusca. This class is made up of a large collection of invertebrates including both snails and slugs. Gastropods are amongst the few groups of animals that have successfully survived in the ocean, fresh waters and land. While distribution ranges between these three major habitats, only 5000 species live in freshwater.[7]
Appearance
Many species of freshwater snail within the Hydrobiidae family are difficult to distinguish between based on appearance. The size range between Hydrobiids is 1-7mm, placing them on the smaller side of the Gastropod class. Shells in this family typically take the appearance of a white or brown to opaque colour with varying thickness from a thin to fairly solid structure. Patterns or ‘whorls’ on the shell vary from a dextrally coiled appearance to planispiral averaging 2-8 whorls.[4]
In regards to appearance, Beddomeia Camensis is fairly ‘average’ within Hydrobiidae family. It has a gill, an operculum and a shell. The size varies between 2-4 mm and the shell typically ranges in colour from dark brown to opaque.[3] The shell is 2.93-3.68 mm long, 2.15-2.51 mm wide with protoconch of 1.75mm whorls. Beddomeia Camensis’ poses conical to compressed trochiform shells that have between 4 and 8 whorls.[8] Beddomeia Camensis’ are not sexually dimorphic in shape, meaning that, based on appearance, a male cannot be distinguished from a female. Gender can only be distinguished by their reproductive organs which are microscopic.
Distribution
Map of Tasmania identifying location of Beddomeia camensis
The Hydrobiidae family can be characterised by its ‘cosmopolitan’ distribution, meaning that is essentially locatable almost anywhere in the world. This family is locatable in freshwater habitats only, however, Gastropods as a class are widely spread through marine and land environments as well. Marine and land species account for 93% of the Gastropod class population meaning that freshwater species’ make up only 7%.[9] This is due to the fact that snails and slugs are better adapted to marine and land environments. As a result of this, some species of Hydrobiidae, such as Beddomeia camensis, are limited to a small selection of freshwater environments that can sufficiently support their life.
Evidently, the distribution of Beddomeia Camensis’ is limited to only 5 small to medium-sized streams that flow in the cam river catchment on Oonah Road in Northwest Tasmania (shown in the map on the right).[3] This area in total covers only a 7km radius. They can be found on small allochthonous material including leaf litter, woody debris and rocks in the stream channels. They typically will resign on the underside of this material where there is moisture and, more importantly, protection from direct contact with elements such as rain, wind and sun.[3]
Anatomy and Reproduction
Over 30,000 species of Gastropods are suited to marine environments and only 5000 to freshwater. This is due to the fact that marine environments are better suited for reproduction and dispersal. Marine Gastropods are aided by the flow of waves, currents and tides which evenly distribute offspring, whereas, in freshwater environments, movement can only be ‘downstream’. As a result, the success and strength of populations within the Hydrobiidae family has been characterised largely by a unique reproductive adaptation. Some freshwater snails (mainly within the pulmonata subclass) are Hermaphrodites, meaning they have adapted the ability to self-fertilize which, in turn, allows a species to maintain population growth individually. This adaptation, however, has been possessed by very few species within the prosobranchia subclass, to which Beddomeia Camensis belongs.[10]
Beddomeia Camensis’ are not hermaphrodites and, therefore, reproduce through sexual reproduction between a male and a female. The females lay eggs that range from 0.87-1.03mm in length which is 30% of the average adult body size. Interestingly, eggs develop into fully grown juvenile size before emerging from the shell, a unique characteristic for Gastropods. This adaptation utilises the ideal growing conditions within the egg, being a warm, moist and protected environment
The visual system possessed by Beddomeia Camensis’ is called lens eyes. Outlined by Britanica, “Relative to pinhole eyes, lens eyes have greatly improved resolution and image brightness.” The form of locomotion adopted by the snail is called mucus mediated gliding, defined by EOL as “muscular waves propelling an animal over a mucus layer overlaying the substrate; alternating regions of muscular contraction and expansion create traveling waves that shear the mucus, resulting in translation of the animal.” [10]
Threats to population
Example of side stream land clearing
The limited distribution of Beddomeia camensis is not only due to its limited fecundity but also due to a number of human induced activities that, in combination with natural threats to the population, have led to the species becoming endangered. Unfortunately, this is a widely spread issue amongst the genus with beddomeia camensis being 1 of 37 beddomeia species listed as threatened or endangered under the Tasmanian Threatened Species Protection act.[3] Naturally, this occurs due to its limited fecundity, as mentioned previously. Fecundity represents a species “potential reproductive output”[11] through the lifetime of an individual organism. Fecundity is closely related with fertility, yet it differs in the following way. Fertility covers the natural ability to produce offspring while fecundity focuses on the potential for reproduction. As a result, fecundity plays a vital role in the regulation of population size.[12] In the case of Beddomeia Camensis, while fertility of females and males is not problematic, fecundity is amongst females, acting as a key natural resistant to mass population growth and distribution. In addition to fecundity, another natural pressure that has grown more prevalent in the last few centuries has been competition from Potamopyrgus antipodarum, a species native to New Zealand, recently introduced to Tasmania.[3]
On top of these factors, that already lead to moderately high vulnerability in the species, Beddomeia camensis has been further pressured by human imposed threats including agricultural and livestock clearing, forestry, mining and impoundment construction.[3] Agricultural clearing includes the clearing and burning of sidestream vegetation and replacement with agriculture or livestock. In regards to river catchments such as the Cam River, side stream vegetation is a vital natural defence mechanism that offers protection against sediment pollution and control over soil erosion.[13] In the circumstance of agriculture, chemicals such as pesticides in addition to increased erosion and runoff into the river catchments which alters nutrient levels in the environment.[14] In extreme cases this can lead to the outbreak of toxic algae in the streams. Stock grazing can further intensify this effect as grazing directly removes side stream vegetation and vastly increases erosion, due to the movements of livestock.
Responses and solutions to threats
In regards to managing the threatened population of Beddomeia camensis, the primary objective is to preserve and maintain the integrity of the natural habitat. As mentioned in the previous section, the most significant overarching threat to the population is loss of habitat due to agricultural and livestock clearing, forestry, mining and impoundment construction.[3] While it is not economically viable to stop these practices, there are ways in which these can continue without compromising the wellbeing of the freshwater snails habitat. Methods of protecting side stream vegetation include fencing to reduce foot traffic and grazing from cattle, stock watering points that allow cattle to drink from the river in select areas deemed suitable for stock access and rehabilitation where severe damage has already occurred.[15]
Ultimately, for these actions to gain the momentum they require, there will need to be an increase in the information available surrounding the species. With this information, relevant Natural Resource Management committees, local councils and government agencies will be equipped with the knowledge and research required initiate actions that lead to preservation. By improving the legislative preservation status of the species, agreements can then be made with local land owners and farmers to better protect the Cam River catchments.[14][3]
Sufficient information gathering on Beddomeia Camensis will be achieved through further more thorough research into the species. This will reveal more detail surrounding information such as population size, distribution, ecological requirements and the direct impact of natural and anthropogenic threats to the population. In addition to professional research, the Tasmanian Threatened Species Link also requests any observations made by members of the community living in the area.[2][3]
The New Zealand mud snail is a species of very small freshwater snail with a gill and an operculum. This aquatic gastropod mollusk is in the family Tateidae.
Fluvidona anodonta or more commonly known as the North Pine River freshwater snail is a species of minute freshwater snail that is endemic to Australia. Originally discovered in 1892 by Hedley & Musson, the snail is highly elusive and only has been sighted four times since its discovery. The snail is 2 mm long and 1 mm wide with the shell colouring being of a yellow-whiteish shade. Fluvidona anodonta resides within the Moreton Bay Region, specifically in four river systems within the D'Aguilar National Park, Queensland. The four river systems are the South Pine River headwaters, the North Pine River headwaters, Kobble Creek and Low Branch Creek. The snail is found under deeply submerged rocks within permanent freshwater systems.
The Tumbling Creek cavesnail is a species of freshwater cave snail with gills and an operculum, an aquatic gastropod mollusk in the family Amnicolidae.
Beddomeia averni is a species of very small freshwater snail that has a gill and an operculum, an aquatic operculate gastropod mollusk in the family Hydrobiidae. This species is endemic to Australia. The Hydrobiidae snail has been categorized into four distinct groups: Beddomeia being one of them. Very little is known about their ecology and habitat. Low funding in Australia for the conservation of threatened species is partly responsible for this; moreover, there are only a few good sources that contribute to its limited data required to have a better understanding. Studies have shown that it is hard to distinguish the species from a morphology point of view. A non-taxonomist may find it arduous to tell differences among different members of the species. Therefore the anatomical study is incorporated to understand and differentiate them. It is found that human-led actions such as agriculture, forestry, mining, etc have caused major degradation in their population. Other factors such as changes in water conditions due to sedimentation, varying temperature, mineral level, salinity can either positively/negatively impact their population
Beddomeia capensis is an aquatic operculate gastropod mollusk, a species of very small freshwater snail that has a gill and an operculum, in the family Hydrobiidae. The species is classified as endangered and known to be endemic to five streams within a relatively small area on the island state of Tasmania, Australia. However, recent surveys have only been able to locate Beddomeia capensis in two small streams on Table Cape, with the total length of inhabited stream less than 80 metres (260 ft).
Beddomeia fultoni(B. fultoni) is a species of small freshwater snail belonging to the family Tateidae.
Beddomeia hallae, also known as Buttons Rivulet hydrobiid snail, is a species of small freshwater snail that is endemic to Australia. The species is an aquatic operculate gastropod mollusk in the family Hydrobiidae. Beddomeia hallae belongs to the genus Beddomeia, which is the largest group in the family Hydrobiidae, consisting of 47 species. In the Threatened Species Protection Act 1995, this species is one of the 37 Beddomeia species listed as endangered, however, on the International Union for Conservation of Nature Red List, the species is listed as vulnerable. Found in Tasmania, in the streams of Buttons Rivulet and Castra Rivulet, Beddomeia hallae is sighted in its natural habitat amongst wood, leaves and under stones. Nonetheless, the Beddomeia species including Beddomeia hallae are geographically isolated, existing within restricted ranges.
Beddomeia launcestonensis is a species of very small freshwater snail that has a gill and an operculum, an aquatic operculate gastropod mollusk in the family Hydrobiidae. This species is endemic to Australia.
The Beddomeia minima is a population of freshwater snails that are endemic to Australia. It is commonly called a hydrobiid snail. This population was listed as Vulnerable on the IUCN Red List in 2011 due to its distribution being restricted to a single location and range of possible threats present in Tasmania. The Beddomeia minima is one of a few fresh water snail species belonging to the same genus Beddomeia that survive in Tasmania, Australia, specifically a single location in the Scottsdale area.
Beddomeia phasianella is a species of snail in the family Tateidae. It is a very small freshwater snail that has a gill and an operculum, an aquatic operculate gastropod mollusk. This species is endemic to Tasmania.
Beddomeia protuberata is a species of endemic freshwater snail in the family Tateidae, found in northern Tasmania, Australia. The shells look ovate and periostracum yellow with some pustules, length between 2.29 mm and 2.93 mm and width between 2.01 mm and 2.34 mm. Beddomeia protuberata has 1.75 protoconch whorls. Its image of microsculpture is uniform and its wrinkles arranged weakly and helically. The teleoconch of beddomeia protuberata has 2.2 to 2.7 convex whorls, and the ratio of convexity is 0.15 to 0.24. Sculptures of the teleoconch are vague with prosocline growth lines. The margin of the last whorl is evenly circular. The thickness and width of inner lips are medium sizes, and the columellar swelled up prominently. The outer lips of Beddomeia protuberata is prosocline, which means the shell leans forwards compared to the shell’s coiling axis. The width of their umbilicus is between 0.31 mm to 0.51 mm. The umbilicus of female beddomeia protuberata are wider than the umbilicus of male.
Beddomeia tumida is a species of very small freshwater snail that has a gill and an operculum. It is an aquatic operculate gastropod mollusc in the family Hydrobiidae, and is endemic to Australia.
Beddomeia waterhouseae, also known as Claytons Rivulet freshwater snail, is a species of freshwater snail in the family Tateidae. This species is endemic to northern Tasmania in Australia. The holotype specimen was found in a very small tributary of Little Clayton's Rivulet and is held at the Australian Museum. B. waterhouseae is small and as an adult has a shell measuring between 1.7 to 3.7 mm in length. The shell shape is ovate-conic to broadly conic and has a thin inner lip and no columellar bulge. This species feeds on algae and detritus on rocks. The female of the species lay single eggs in capsules made of sand grains and attached to the underside of rocks or wood. B. waterhouseae is considered vulnerable by the IUCN as it has a very small range and is sensitive to water quality and so may be threatened by disturbances of its habitat. Other threats include habitat loss. Conservation activities such as assessment of the aquatic ecosystem and vegetal surveys are being undertaken in an attempt to preserve this species.
Carnarvonchochlea exigua, more commonly known as Jardinella exigua is a small freshwater snail residing in North East Queensland, near Carnarvon Gorge. Carnarvoncochlea refers to the location of origin, whilst exigua derives from the latin word “exigus” meaning “small”.
Mercuria similis is a species of small freshwater snail with an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.
Trochidrobia inflata is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Tateidae. This species is endemic to Australia. Trochidrobia inflata derives the name inflata from the inflated shell of this species.
Peringia ulvae, common name the Laver spire shell or mudsnail, is a European species of very small aquatic snail with gills and an operculum, a gastropod mollusk in the family Hydrobiidae.
Freshwater molluscs are those members of the Phylum Mollusca which live in freshwater habitats, both lotic such as rivers, streams, canals, springs, and cave streams and lentic such as lakes, ponds, and ditches.
Freshwater snails are gastropod mollusks that live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs to major rivers. The great majority of freshwater gastropods have a shell, with very few exceptions. Some groups of snails that live in freshwater respire using gills, whereas other groups need to reach the surface to breathe air. In addition, some are amphibious and have both gills and a lung. Most feed on algae, but many are detritivores and some are filter feeders.
Spurwinkia salsa is a species of very small aquatic snail, an operculate gastropod mollusk in the family Cochliopidae.
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