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Archive for March 2013

For Peat’s Sake…

March 27th, 2013 — 3:19pm

Surely it’s time we stopped using this valuable, non-renewable natural resource in our tanks, says Matt Ford

Satellite photo of the island of Borneo taken August 19 2002 showing smoke from burning peat swamp forests © Jacques Descloitres

Among the multitude of freshwater fish species available in the aquarium hobby a great number of them hail from tropical forests in South America, Africa and Southeast Asia, and one prevailing image of how their habitats might look is that of peaty forested streams and pools containing tea-coloured blackwater.

Aside from its distinctive colour the water is also typically acidic, rich in humic substances, nutrient-poor and inhospitable to most microorganisms, so we often attempt to simulate these natural conditions in our tanks to promote optimal health and breeding in our fishes.

There are several popular methods and one of the most widespread is the use of natural peat, often in the form of peat ‘moss’, compressed granules or pellets, in liquid ‘blackwater extract’-type products, or more rarely in its unrefined, fibrous state.

Most of the peat we use in aquaria is formed from mosses of the genus Sphagnum and sold in both dried and processed formats © Ragesross

The use of peat in whatever format is perhaps worthy of reconsideration, though, and here’s why…

What is peat and why is it important?

Peat is an organic material formed by partially-decomposed vegetation under waterlogged conditions which accumulates faster than it breaks down.

It typically forms in bogs, swamps and similar habitats where conditions are lacking in oxygen, preventing the activity of microorganisms and reducing the rate of decomposition.

As the peat accumulates it’s also able to store more water and the area of bog thus expands.

Peat bogs dominated by Sphagnum tend to be acidic © James K. Lindsey

Under normal circumstances plant material produces the greenhouse gas carbon dioxide when it decomposes but in such an oxygen-deficient bog or swamp it’s stored as carbon and ‘locked’ from escaping into the atmosphere.

Peat-rich environments therefore provide an essential environmental function as enormous carbon sinks at the global scale, with those remaining in the UK alone storing more carbon than all of Europe’s forests combined.

The most recent estimate that global peatlands contain approximately 650 Gt (gigatonnes) of carbon, about 80 times more than annual emissions from the fossil fuel industry which produces around 8 Gt.

Peat also accumulates gradually over thousands of years, so cannot be replaced once removed, and therefore in no way can it be considered a renewable or sustainable resource.

Besides all this peat-rich environments support diverse and unique biological communities that can never be regained once lost.

Bog Asphodel, Narthecium ossifragum, is a typical inhabitant of damp, peaty soils in Western Europe © Colin Dunlop

Many bog plants are highly-specialised, for example, and include iconic species such as the carnivorous sundews, Drosera spp., and venus fly trap, Dionaea muscipula, while well-known aquatic genera such as Cryptocoryne and Barclaya are native to peat swamp forests of Southeast Asia.

The physical and chemical properties of peat depend on the type of vegetation involved in its formation, and the stuff we use in aquaria tends to be harvested in Canada and dominated by mosses of the genus Sphagnum, commonly referred to as peat or bog mosses.

Sphagnum bogs are normally acidic due to the mosses’ tendency to absorb cations such as calcium and magnesium while releasing hydrogen.

They can exist in several different forms, from ‘string’ bogs comprising a series of elevated ridges and islands or ‘raised’ bogs where the peat accumulates above the point where water is able to reach its centre and forms a dome or mound, to ‘floating’ bogs in which the bog vegetation forms a thick mat floating on water or very wet underlying peat.

Carnivorous plants such as this Drosera sp. are common in peat bogs. Nitrogen, phosphorus and other nutrients are usually scarce in such conditions so the plants obtain them from captured insects © Colin Dunlop

Other types of peat wetland may have neutral to alkaline water chemistry and relatively high concentrations of dissolved minerals with vegetation typically consisting of sedges and grasses.

These are normally referred to as fens rather than bogs with the pair collectively known as mires.

Which part of the world does it come from?

The largest areas of peatland lie in boreal and subarctic regions, particularly northwestern Europe, western Siberia, central Canada and Alaska.

Important peatlands are also found in tropical Africa, Southeast Asia and in recent years the existence of extensive peat deposits in the western Amazonian lowlands has also been confirmed having only rarely been considered in the past.

Typical unspoiled blanket-type peat bog in Scotland, United Kingdom © Colin Dunlop

Why, how and to what extent is peat being exploited?

Peat has been used as an energy source for at least 2000 years and today is still excavated in industrial quantities then dried for use in horticulture and as a fuel.

The traditional method of removal is hand-cutting using a specially-designed spade known as a sleán or slane in such a way that the peat layer is able to continue to grow after harvesting.

Although a laborious, time-consuming process hand-cutting does permit recovery of peat to a certain extent since it usually takes place on a relatively small scale.

More common in modern times is industrial-scale mechanised extraction using either an auger (aka sausage machine) or digger-and-hopper with the latter in particular resulting in rapid deep-draining of the peat, stripping of surface vegetation and irrevocable destruction of entire wetlands.

Mechanical harvesting of peat tends to cause irreversible damage to bog habitats. Compare this scene with the previous image © M. J. Richardson

In the United Kingdom, for example, a combination of draining and ditching plus an ill-conceived attempt to use bogs for planting of sitka spruce trees by the paper industry in the 1980s has already resulted in the loss of over 90% with only 6000 hectares (ha.) of the original 95,000+ ha. remaining.

Peatlands are also destroyed in order to replace them with large-scale agricultural projects and during the last decades such exploitation has had a negative effect on carbon storage and biodiversity, increasing carbon emissions, enhancing global warming and driving thousands of species towards extinction.

This is perhaps most evidently seen in the mass-clearing and burning of peat swamp forests in Southeast Asia which continues today but was exemplified by the Indonesian government’s failed ‘Mega Rice Project’ during the late 1990s.

In 1997 fires in Kalimantan and Sumatra released 0.81-2.57 Gt of carbon into the atmosphere, representing 13-40 % of that year’s global carbon emissions and causing the 1997 Southeast Asian haze.

An area of former peat swamp forest in Riau province, Indonesia (Sumatra) after being burned for replacement with oil palms © Aid Environment

Although the MRP was abandoned, and has subsequently been considered one of the great environmental disasters of our time, clearing and burning of peatlands continues across Southeast Asia and one hypothesis predicts that at the current rate of loss there will be no more peat deposits in the region by 2040.

Should this occur the catastrophic loss of endemic species would include a host of well-known aquarium fishes such as members of the genera Betta, Parosphromenus, Rasbora, ‘Puntius’, Boraras, Sundadanio and Pangio, many of which are already at risk of extinction.

Fishkeepers can hardly be blamed for all this though, can they?

Of course not, but is there really a need to contribute to the destruction of such important natural habitat?

Although the amount of peat consumed by the aquarium industry is in no way comparable to that used in the manufacture of horticultural products or fuel our hobby is consuming by nature and this is one way in which it can take a positive step to become less so.

Many fishkeepers also tend to demonstrate an interest in the natural world so given this is a genuine environmental issue maybe it’s time to reassess the use of peat in our tanks and seek equally useful but more sustainable alternatives.

Many Betta species are stenotypic inhabitants of peat swamp forests and are disappearing along with their habitats © Haji Badaruddin

But surely if the fishes I keep come from environments influenced by peat I need to use it in their aquarium?

Actually in most cases the answer is no.

The chemical properties of peat are affected by local vegetation-types, the environment in which it’s deposited and the extent of decomposition, with pH normally ranging from 4.0 – 7.0 but sometimes being as low as 3.0, for example.

Any peat or peat-based product used in the aquarium is therefore extremely unlikely to match that occurring in the natural habitat of our fishes.

Peats formed from sedges such as Carex spp. tend to be neutral or alkaline rather than acidic © Hermann Schachner

The primary organic constituents of peat are often referred to collectively as humic substances of which a principal component is humic acid, and this is often said to be important for species which naturally inhabit black water environments.

However, humic acid actually refers to a complex mixture containing a number of different acids rather than a single substance and is formed from biodegradation of plant material in general rather than a single particular group.

In the aquarium a similar effect can be obtained by using leaf litter or alder cones, both of which release humic acids when allowed to decompose in water.

You may also be able to collect these yourself which is easier on the pocket, and it goes without saying that the use of dead leaves and cones is more environmentally-friendly than peat.

Alder cones offer similar advantages to peat in the aquarium and you can collect them yourself © Anneli Salo

Moreover peat does not exert a significant effect on water chemistry in the quantities normally used in aquaria and is not useful as a means of acidifying water (the same can be said of leaves and alder cones) rather the chemicals it releases are considered beneficial to certain fish species.

In harder water these benefits are reduced and the use of a reverse osmosis unit or other form of water purifier, often with the addition of supplements such as phosphoric acid, is normally required to achieve a sufficiently low pH for sensitive blackwater species.

Leaves or alder cones can then be used to provide optimum conditions and will offer much the same benefits as peat.

What about killifishes?

Peat is traditionally used as a medium for spawning and egg storage of annual killifishes but there are a few alternatives of which the most popular is arguably coconut fibre or ‘coir’.

Coconut fibre or ‘coir’ can be used to store killifish eggs © Matias Miika

This is made from the fibrous husk material which surrounds a coconut, is essentially an industrial by-product and although not entirely kind to the environment is at least considered a renewable resource.

It’s usually shipped in the form of compressed bales, briquettes, slabs or discs, is cheap to buy and an excellent medium for eggs although you may need to experiment a little to obtain the best results if accustomed to using peat since it tends to dry at a faster rate.


Lähteenoja, O. and K. H. Roucoux. 2010. Inception, history and development of peatlands in the Amazon Basin. Past Global Changes News 18(1): 27-29

Joosten, H., M-L. Tapio-Biström and S. Tol (eds.). 2012. Peatlands – guidance for mitigation updated report. FAO and Wetlands International: 1-100

Billett, M., D. J. Charman, J. M. Clark, C. Evans, M. Evans, N. Ostle, F. Worrall, A. Burden, K. Dinsmore, T. Jones, N. McNamara, L. Parry, J. Rowson, and R. Rose. 2010. Carbon balance of UK peatlands:  current state of knowledge and future research challenges. Climate Research 45: 13–29

Thanks to Colin Dunlop for comments.

Category: Articles, Conservation | Tags: , , , , , , , | 6 comments »

Rasbora dusonensis and R. tornieri redescribed

March 27th, 2013 — 11:02am

Preserved specimens of R. dusonensis (top) and R. tornieri (bottom), both collected from the Sungai (river) Gelam, Sumatra © Ng & Kottelat

The identities of both species have been unclear for a number of decades but are resolved in a new paper by ichthyologists Heok Hee Ng and Maurice Kottelat published in the journal ‘Zootaxa’ last week. Continue reading »

Category: Ichthyology, News | Tags: , , , | Comment »

Scientists confirm first two-headed bull shark

March 26th, 2013 — 8:27am

Specimen after being removed from the body of its mother © Michael Wagner

Scientists have confirmed the discovery of the first-ever, two-headed bull shark.

The study, led by Michigan State University and appearing in the Journal of Fish Biology, confirmed the specimen, found in the Gulf of Mexico April 7, 2011, was a single shark with two heads, rather than conjoined twins. Continue reading »

Category: Discoveries, News | Tags: , , | 2 comments »

The Desert Fish Habitat Partnership

March 25th, 2013 — 3:05pm

The goodeid Crenichthys baileyi is a focal species for the Desert Fish Habitat Partnership. © Barbara Nicca

The conservation of freshwater fishes and their habitats is set to establish itself among the most pressing environmental issues worldwide over the next few decades as freshwater resources become ever-more exploited.

Continued deforestation, the construction of dams for hydroelectric projects or drinking water and extraction of groundwater are just three of the conspicuous, often irreversible, ways in which man has had a detrimental impact on freshwater ecosystems, but only rarely are we hobbyists made aware of the extent to which things have already declined.

Hope does exist in the form of numerous international conservation groups, however, many of which are maintained by scientists or institutions, others by aquarists themselves, and in some cases a combination of both.

In order to raise awareness and hopefully encourage interest in this valuable work we’ll be running a new series of blogs and articles covering some of the great stuff already being done, and showing how the aquarium hobby can and does play a valuable role.

We begin with the Desert Fish Habitat Partnership (DFHP) which has the primary aim of bringing together ‘people and organisations with a common interest in voluntary conservation of desert fishes and their habitats’.

In the southern United States desert-dwelling fishes are often restricted to artesian springs such as the ‘Point of Rocks’ spring in Ash Meadows National Wildlife Refuge. © Stan Shebs

Now the populist image of a desert is not one normally associated with aquatic life, so it may be surprising to learn that freshwaters of the arid southwestern United States are home to at least 179 non-salmonid fish species among which are 30 % of all threatened and endangered species in the country.

The DFHP was formed in 2005 to help protect them, and seeks to address conservation issues over a vast area encompassing the Great Basin and Mohave deserts plus those portions of the Sonoran and Chihuahuan deserts that lie within the U.S.

The majority of these fishes are largely unknown in the aquarium hobby although they include representatives of some familiar groups, including killifishes such as Lucania parva and various members of the genus Cyprinodon, the goodeids Crenichthys baileyi, C. nevadae and Empetrichthys latos plus a few species of livebearing Gambusia, with the families Cyprinidae and Catostomidae being particularly diverse.

Habitat loss or alteration, and introduction of non-native aquatic species such as western mosquitofish, Gambusia affinis, and sailfin molly, Poecilia latipinna, has resulted in the decline of desert fishes throughout this region, and the DFHP has developed an ever-increasing network of state and tribal fish and wildlife agencies, federal resource agencies, research and private organisations, and engaged individuals with the collective goals of protection, restoration, and enhancement of desert fish habitats.

Empetrichthys latos is now the sole extant member of its genus with its former congener E. merriami not having been collected since 1948. © Shawn Goodchild

The degree of cooperation over a wide geographic area is perhaps the single most impressive achievement of the group to date with similar attempts often failing elsewhere, and I speak from personal experience here, due to a combination of limited funding, inconsistent coordination, and more often than not problems with geographic and jurisdictional boundaries.

In this respect the DFHP can perhaps be considered an excellent model upon which to base efforts in other countries, so check out their contact details at the end of this piece to find out more.

But enough talk of legislation and what-not, let’s take a look at some of the fish species covered by the project and focus on some of their notable successes to date.

2010: Ash Meadows Armagosa pupfish, Cyprinodon nevadensis mionectes and Ash Meadows speckled dace, Rhinichthys osculus nevadensis

Ash Meadows National Wildlife reserve is the largest remaining series of oases in the Mojave Desert, in southern Nevada state, the major discharge point in the Death Valley Regional Aquifer and can be considered the birthplace of the desert fish conservation movement.

It’s home to 26+ endemic species of which at least 12 are critically-endangered, among them a number of fishes, and has been protected as the Ash Meadows National Wildlife Refuge since 1984.

Ash Meadows National Wildlife reserve is the largest oasis in the Mojave Desert and is located in southern Nevada state. © Stan Shebs

This project aimed to restore several miles of outflow from Fairbank and Soda springs at the northern end of the refuge.

These had been drained and mined for peat in the 1950s and 1960s after which the area was leveled, tilled, and converted to agriculture with the springs diverted for irrigation.

As a result the resident dace population disappeared and at one point was reduced to just two springs in the southern part of Ash Meadows.

The subspecies Cyprinodon nevadensis mionectes inhabits Fairbank and Soda springs. © Stan Shebs

A plan was put together and the springs restored to follow their historic flow patterns via modification of roads, ditch and impoundment removal, construction of low-water crossings, and improvements in fish passage including culvert and fish barrier installation.

In early 2010 a group of volunteers collected 3,150 pupfish and 12,000 endemic snails from the degraded outflow of Fairbank spring and relocated them to the restored outflow. 2,710 non-native red swamp crayfish, Procambarus clarkii, were also removed and destroyed.

Dace were introduced into the upper part of the spring in April and August 2010 and appear to be successfully reestablishing in the system for the first time in 50 years, while restoration of native vegetation and removal of non-native animals continues.

Unfortunately the management plan came too late to save the Ash Meadows poolfish, Empetrichthys merriami, a member of the Goodeidae family which has not been seen anywhere since 1948.

2011: Comanche Springs pupfish, Cyprinodon elegans, and Pecos gambusia, Gambusia nobilis

Both of these species formerly occurred in a series of artesian springs in the Pecos River basin close to the towns of Balmorhea and Fort Stockton in the state of Texas, but the latter habitats dried out completely in the mid-1950s and the fish were wiped out.

The pupfish is now found only in the springs around Balmorhea while the gambusia occurs both at Balmorhea and a handful of other localities.

A refugium consisting of man-made canals and a large lake was constructed in Balmorhea State Park in 1975, and these remain in use today.

The restored spring at Balmorhea State Park. © Larry D. Moore

Phantom Lakes Spring is one of those feeding this system with its headwater located a few kilometers away from the park, and its outflow has been in steady decline since the 1940s.

The pool formed as the spring exits a cave system has been maintained by a pump plus a number of short-term ‘fixes’ since 2001.

A project organized by the DFHP and actioned in 2011 stabilised the pool and a larger, more natural ciénega (spring-fed wetland system) was constructed.

2012: Moapa dace, Moapa coriacea, Moapa White River Springfish, Crenichthys baileyi, Virgin River chub, Gila seminuda, and Moapa speckled dace, Rhinichthys osculus moapae

Apcar Spring is one of 25 thermal source springs for the Muddy (aka Moapa) River in the ‘warm springs’ area of Clark County, Nevada state and historically home to all four of these endangered species.

It was originally carpeted with aquatic vegetation but following invasion by non-native Gambusia, Poecilia and Tilapia had become seriously degraded by the mid-1990s.

The upper Apcar was rehabilitated from 2007 onwards via removal of non-native species and habitat restoration.

Restoration of the upper Apcar Spring in 2007. © Shawn Goodchild

The original culvert seen here has now been replaced by a larger box culvert allowing fish to pass more easily. © Shawn Goodchild

Moapa dace were reintroduced to the system and a stable population developed, but it was separated from additional habitat in lower sections of the system by an under-sized, raised culvert.

In 2011 a DFHP team of volunteers installed a much larger box culvert which allowed the spring to flow freely once more and restored connectivity to an important section of the spring system.

Moving forwards…

Work ongoing during the latter part of 2012 and into 2013 include projects to restore habitats for a host of species including Shoshone pupfish (Cyprinodon nevadensis shoshone), Big Spring spinedace (Lepidomeda mollispinis pratensis), Meadow Valley Wash speckled dace (Rhinichthys osculus ssp.), Meadow Valley Wash desert sucker (Catostomus clarkii ssp.), Conchos pupfish (Cyprinodon eximius), Chihuahuan shiner (Notropis chihuahua), Mexican stoneroller (Campostoma ornatum), Roundnose minnow (Dionda episcopa), Mexican tetra (Astyanax mexicanus), Bluehead sucker (Catostomus discobolus), Utah sucker (Catostomus ardens), Colorado cutthroat (Oncorhyncus clarkii pleuriticus), speckled dace (Rhinichthys osculus), Longnose dace  (Rhinichthys cataractae), Redside shiner (Richardsonius balteatus) and many more.

The Moapa dace, Moapa coriacea. © Shawn Goodchild

How can I help?

The conservation of freshwater fishes is basically impossible without effective habitat protection or in extreme cases, restoration, and this is a priority for the DFHP that groups in some other countries would do well to take inspiration from.

As a result of this physical aspect they’re always looking for volunteers and can be contacted using the details at the bottom of this page, so if you live in or close to the area covered by the group simply get in touch!

Cyprinodon spp. and goodeids

Most of the species mentioned here are not available in the aquarium hobby for obvious reasons, but pupfishes, Cyprinodon spp., and goodeids, the group within which Crenichthys spp. are included, are endangered across their ranges.

Some have already disappeared in the wild and kept alive only via breeding programmes in zoos and private aquaria.

For example the Potosi pupfish, C. alvarezi, is now considered extinct in nature but is being maintained by a number of aquarists around the world, and the same is true of the goodeid Allodontichthys polylepis among others.

Cyprinodon alvarezi, the Potosi pupfish, is already extinct in nature. © Barbara Nicca

The former was originally native to a handful of localities in San Luis Potosi State, Mexico but these are now desiccated due to water extraction and it hasn’t been recorded there for a number of years while the latter hasn’t been collected in the wild since 2000 despite its former habitats appearing in an acceptable state.

The reality is, and this is no exaggeration, that without the efforts of aquarists these species would already be gone forever.

If you want to get involved in such captive-breeding projects the best thing to do is contact your local aquarium club and take it from there, but please read as much as you can on the subject and be aware of the responsibility involved before doing so.

Visit the Desert Fish Habitat Partnership website

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Ash Meadows National Wildlife Refuge

Category: Articles, Conservation | Tags: , , , , , , | One comment »

Archerfish get an eye test

March 22nd, 2013 — 9:23am

© Klaus Rudloff

A modified version of an eye test used to assess visual acuity in the military has been given to archerfish by scientists to help explain how these remarkable fish are able to accurately spit down tiny insects high above the water’s surface. Continue reading »

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Identity of aquarium glass catfish resolved

March 20th, 2013 — 2:50pm

K. vitreolus is well-known to aquarists but has been misidentified for at least 80 years. © Unimati.dk

Over the last few decades the aquarium glass catfish has generally been referred to as Kryptopterus bicirrhis or, more recently, K. minor in both aquarium and scientific literature, but a new paper by Drs. Heok Hee Ng and Maurice Kottelat reveals that this popular species has in fact been misidentified for over eighty years. Continue reading »

Category: New Species, News | Tags: , , , , | 2 comments »

Have you seen Xenoophorus captivus?

March 12th, 2013 — 9:19am

Adult male individual from the Illescas population, where wild fish have not been collected since the 1990s. © Frank Krönke

This is an appeal on behalf of the Goodeid Working Group (GWG) who are searching for anyone maintaining the critically-endangered species Xenoophorus captivus.

The majority of goodeid species are threatened with most having declined since the late 1990s and X. captivus has long been suffering from habitat loss due to pumping of groundwater and diversion of natural springs for irrigation and drinking water.

Adult female from Illescas. © Frank Krönke

It was originally known from seven localities in three geographically-disparate areas in the states of San Luis Potosí and Zacatecas, Mexico, some of which are located in endorheic drainage basins with the others forming part of the upper Pánuco River, but by 2003 three of them had already disappeared.

Recent news received from Mexican aquarist and naturalist Juan Miguel Artigas Azas paints a depressing picture of the current situation, as he had been unable to find the species at its type locality, the Río Santa Maria, or any of the upper Pánuco localities with the habitats completely dessicated and unable to support fish of any kind.

Male specimen from the Río Santa Maria, type locality of the species from where it may now have disappeared. © Anton Lamboj

Worse, this species is very rare in the aquarium hobby, so the GWG has launched an urgent appeal to try and find any remaining populations being maintained in captivity.

If you keep, or know someone who keeps, this species, especially fish of the ‘Moctezuma’, ‘Venados’ and ‘Agua de Enmedio’ populations, please get in touch with the GWG via their website and you may be able to help preserve it.

Adult female from the Río Santa Maria. © Anton Lamboj

The GWG is a non-profitable international working group formed in 2009 in response to the critical environmental issues facing the majority of wild goodeid species and the poorly-documented ‘disappearance’ of many captive collections.

Keep an eye on the site as we’ll be featuring the group’s work in greater detail shortly.

Category: Blogs, Conservation | Tags: , , , , , , | 4 comments »

W. L. Minckley’s library now available online

March 8th, 2013 — 9:14am

Dr. Minckley conducted a significant amount of work on endangered species at Ash Meadows National Wildlife Refuge, Nevada, United States. © Stan Shebs

The late ichthyologist Dr. Wendell Lee Minckley (1935-2001), one of the founding members of the Desert Fishes Council and a lifetime supporter of its work, will be well-known to those familar with freshwater fishes of the southwestern United States and Mexico.

He studied aquatic ecosystems and southwestern fishes, authoring a number of books, research articles and book chapters as well as co-authoring ‘Freshwater Fishes of Mexico’ with Robert Rush Miller, the latter eventually being published in 2005. Continue reading »

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New tetra from the rio Xingu basin

March 6th, 2013 — 10:05am

Live specimen of E. altipinnis. © Netto-Ferreira et al.

A new miniature characid genus and species from the rio Curuá at Serra do Cachimbo, Pará state, Brazil. has been described in the open access journal PLoS ONE.

Erythrocharax altipinnis is the only known member of the new genus and can be told apart from related groupings by having the pelvic bones firmly attached through the horizontal isquiatic processes. Continue reading »

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