The vivarium issue 3 vol 3 - Autumn/Winter 2015

www.zoomed.eu

www.zoomed.com

www.vivariumnews.com

http://www.zoomed.com

Editorial

Ashley RademacherAnimal Care and Education CoordinatorZoo Med Labs

Every year, I look forward to traveling out to Mesa, Arizona to attend the Turtle and Tortoi-

se Preservation Group (TTPG)’s annual confe-rence. For three days, turtle and tortoise fanatics gather to share their knowledge and passion for all species of chelonians. This fantastic organiza-tion is dedicated to preserving all species of turt-les and tortoises through education and captive breeding. Their goal is to spread the joy of turtle and tortoise keeping, while bringing to light the terrible plight of turtle and tortoise populations declining worldwide.This particular conference includes a tour of a local animal facility, social gatherings, roundtable discussions, a banquet with keynote speakers, and a variety of presentations detailing topics such as the captive care and breeding of turtles and tortoises, conservation statuses, medical ca-ses and techniques, and more. This conference is a great time and way to educate and keep up on Chelonian news while in the company of old friends and associates; you may even make new connections! There is an incredible energy to

being surrounded by people who all love and are passionate about the same things. TTPG isn’t the only way to find and surround yourself with like-minded animal enthusiasts. Reptile shows and fish shows are always diverse and include every category of reptile or fish avai-lable on the market. If you prefer to focus your energy and attention, you may consider atten-ding a symposium or conference. These gathe-rings occur throughout the world and concentrate on a wealth of topics: live-bearer fish, Freshwater Turtles and Tortoises, and Bettas to name a few.During these events, information about captive care, conservation, and wild habitats may be pre-sented in many different forms such as discussi-ons, posters, demonstrations, tours, and more. In my experience, conference and symposium attendees are extremely friendly and delighted to spend hours talking about their favorite topic – their animals. The amount of knowledge and enthusiasm present at these gatherings is un-matched and you are likely to come home feeling motivated to get your hands wet or dirty trying out new techniques with your animals. I have met some of the most inspiring and supportive people at a variety of different animal conferences and look forward to any time I can attend them. If you ever have a chance, I strongly encourage you to attend a conference or symposium and get ins-pired! Here is a list of conferences and symposi-ums that Zoo Med sponsors and participates in. Hope to see you at the next one!

IHS International Herpotological Symposium – May

ALA American Livebearer Association – May

IBC International Betta Congress - June

ACA (American Cichlid Association) – July / August

TSA Turtle Survival Alliance – August

Aquatic Experience – November

TTPG Turtle and Tortoise Preservation Group Conference – November

A list of Zoo Med Sponsored Reptile and Aquatic Shows can be found on our web page at http://links.zoomed.com/repshows.

http://links.zoomed.com/repshows

http://links.zoomed.com/repshows

Contents

Cardinalfish - fascinating and beautiful!

Characins

Oscars

Small and dainty:the Pancake Tortoise

NEW ON THE MARKET!

The dark side of the Hornet Cichlid

The Dwarf Girdled Lizard

8-23

54-57

24-29

4-7

36-45

46-55

30-35

The West African Mud Turtle 58-61

The Vivarium - Issue 3 Vol. 34

The Pancake Tortoise (or Crevice Tortoise) - its scientific name is Malacochersus tornieri

- grows to only 5.9-7.1 in (15-18 cm) long and is thus one of the smallest of all the tortoises! It is its resulting comparatively small space require-ment that makes it so particularly desirable.

Soft shellUnlike in all the other tortoises, the shell of the Pancake Tortoise is relatively soft, very flat, and not suitable for the animal to be able to withdraw its head and other extremities underneath. No wonder that the original describer of the species initially thought he was dealing with a deformed, unhealthy specimen! In all other tortoises a soft shell is indeed an extremely good warning sign, indicating a serious metabolic disturbance that

Small and dainty:the Pancake Tortoise

Tortoises hold a great attraction for all reptile enthusiasts. The European spe-cies are best kept outdoors, but not ever-ybody has a garden to make this possible. Tropical species are often very large and need a lot of space, but not the Pancake Tortoise! by Christoph Fritz, www.reptilia24.com

The name ”Crevice Tortoise” is very appropriate. It was invented by Heinrich Dathe.

http://www.reptilia24.com

The Vivarium - Issue 3 Vol. 3 5

can lead to deformity and in very severe cases even result in the death of the animal. But this isn’t the case with the Pancake Tortoise!

Head for the hills!That is perhaps the best way to describe the sur-vival strategy of the Pancake Tortoise. It is spe-cialized in living in rocky upland habitats. While other tortoises are proverbially slow-moving and withdraw into their shells when danger threatens, the Pancake Tortoise deserves the title of “fas-test tortoise in the world”. If it is threatened then it runs away at a speed of up to 59 feet (18 meters) per minute. Its goal is to find a rocky crevice, and thanks to its highly-developed sense of directi-on it is regularly successful. It then creeps inside and props itself up on its legs, thereby wedging

itself into the crevice. It also breathes in deeply, which increases its size even further - thanks to its soft shell! There is no animal known that can extract a Pancake Tortoise from its hiding-place once it is wedged in this way.

Homeland: East AfricaOriginally it was thought that the Pancake Tor-toise was distributed from central Kenya to southern Tanzania, but recently it has also been recorded further north in Kenya and south as far as Zambia. A particular bird – the Egyptian Vulture (Neophron percnopterus) - may have en-couraged the Pancake Tortoise to evolve. This vulture is in fact one of the few animal species that can crack open tortoises. To do so it grabs the tortoise carries it high into the air, and then

drops it onto a rock to crack it open. According to legend the Greek poet Aeschylus (525 B.C. - 456 B.C.) met his death when this bird mistook his bald head for a rock and smashed a tortoise on it.

Unfortunately seriously endangeredIts specialized habitat doesn’t make for very lar-ge populations of the Pancake Tortoise, and for this reason it multiplies only slowly. That makes it remarkable. It is thought that excessive collec-ting of the species for the terrarium trade may have come to constitute a threat to its survival. For this reason, since 1992 the trade in wild spe-cimens has been banned in Tanzania, while the export of so-called farmed specimens continues to be allowed. It appears that this measure may have been effective, as investigation of the bio-tope has revealed few signs of illegal collection. At the same time the main threats to the species, namely habitat destruction through overgrazing of its food plants by human farmstock, quarrying for building houses, and climate change, conti-nue to exist. Because the Pancake Tortoise can readily be maintained and bred in captivity, we can only hope that as many terrarium enthusi-asts as possible will get involved with this inte-resting species. In the terrarium at least it mustn’t ever become extinct.

Maintenance and breedingThe maintenance of the Pancake Tortoise is re-latively easy. It isn’t possible to give extensive advice on the subject here, and the reader is in-stead referred to the abundant specialist litera-ture that exists. Even so, basically it can be said that these tortoises should be kept at an air tem-perature between 68 and 86 °F (20 and 30 °C) during the “dry season” (June-October, Decem-ber- March) and 77-95 °F (25-35 °C) during the “rainy season”. A sunning place with a tempera-ture of 104-122 °F (40-50 °C), created by a lamp, should be provided. Up to five clutches of eggs per female per year are possible, but as a rule consist of just a single egg. As far as possible the diet should consist of wild plants with a high percentage of soft grasses (Gramineae), while hay can be given as well during the dry season. The necessary rocky crevices can most safely be built using light-weight plastic “rocks” such as are manufactured for the aquarium hobby. If you use natural rock then make absolutely sure that it is safe from collapse! Males are often intolerant of one another, but that is the same as already known for tortoises in general.


The armor of the Pancake Tortoise isn’t suitable for protecting the head and limbs.

Pancake Tortoises can move energetically when they have reason to.


Cardinalfish - fascinating and beautiful!

Marine fish

Cardinalfish can be termed ideal fish for the marine aquarium. They are bright-ly colored, exhibit interesting behavior, remain manageably small, don’t tend to be susceptible to disease, ignore sessile invertebrates, and are essentially ener-gy-saving fish as they require little light. Who could ask for anything more? by Levin Locke

Pterapogon kauderni, the BanggaiCardinalfish, is probably the easiest of allmarine fishes to breed.



Marine and freshwater aquarists are often very committed to their particular branch

of the aquarium hobby. Marine aquarists don’t usually maintain any freshwater aquariums, and vice versa. At the same time very many freshwa-ter aquarists continue to subscribe to the argu-ment that marine fish cannot be bred in private aquariums, or at least only at great expense and effort. For these people breeding is the crowning achievement of keeping fish. Cardinalfish are thus ideally suited as beginner’s fish, as at least one species, Pterapogon kauderni, is no more difficult to breed than an easy-to-breed freshwa-ter fish and in addition it is always easy to find homes for the young.

Cardinalfish - an overviewCardinalfish constitute a family - scientifically known as the Apogonidae - within the perciform fish. At present almost 350 different species are recognized, divided among 33 genera. The lar-gest species of cardinalfish grows to around 8 in (20 cm) long, but the vast majority remain below 4 in (10 cm) in total length. For this reason alone the majority of species are well-suited to long-

term maintenance in the aquarium.Almost all cardinalfish live in the sea; only one ge-nus, Glossamia, with 11 species, restricted over-all to New Guinea and Australia, lives exclusively in fresh water. There are also a small number of euryhaline species, that is fish that can live both in the sea and in fresh water; one of them, na-mely Apogon amboinensis, is occasionally, even though very rarely, imported as an aquarium fish for freshwater aquariums. Please see the “Lexi-con” box for more information on these species.

The cardinalfish received their popular name from the only species originally native to the Me-diterranean, the Cardinalfish or King of the Mul-lets, Apogon imberbis. Its red attire was appa-rently thought very reminiscent of the robes of the church dignitaries. The second popular name of this species comes from the legend that this fish ruled over the Red Mullet (Mullus barbatu-lus), one of the most prized food fish among the ancient Romans. Even the scientific genus name reflects this legend, as ”Apogon” means ”without barbels” - in comparison to the mullets with their two flexible barbels on the chin.

King of the Mullets, Apogon imberbis, from the Mediterranean. All photos: Frank Schäfer


Cardinalfish occur in all the warm seas of the Earth. Originally the only species living in the Me-diterranean was the above-mentioned A. imber-bis, but in the interim a whole series of species have migrated from the Red Sea into the Medi-terranean via the Suez Canal: the so-called Les-sepsian migrants (after the engineer Lesseps, under whose direction the Suez Canal was ope-ned in 1869) Apogon queketti, A. smithi, Apogo-nichthyoides nigripinnis, A. pharaonis, A. taenia-tus, and Ostorhinchus fasciatus. The influence of these newcomers - the technical term is neozoa - on the indigenous fauna of the Mediterranean remains unknown, although the Pharaoh Cardi-nalfish (Apogonichthyoides pharaonis) is a direct competitor for habitat with Apogon imberbis, and populations of A. pharaonis are constantly gro-wing (Oral, 2010). However, the King of the Mul-lets is still considered a common species and not endangered, and it remains to be seen how well A. pharaonis can adapt to the low temperatures in the western Mediterranean. At present its oc-currence is restricted to the eastern Mediterra-nean.

Unusual relationships It is known that many cardinalfish species live in close association with other creatures. Thus some species live among the long venomous spi-nes of sea urchins of the genus Diadema. The Banggai Cardinalfish (Pterapogon kauderni), al-ready mentioned above, is particularly well known for this association, but the species most highly specialized on this partner is undoubtedly Ostor-hinchus chrysotaenia; this cardinalfish has even been observed to clean the sea urchin. So the relationship is probably a true symbiosis offering reciprocal benefits, while the use of sea urchins by other cardinalfish, without the sea urchin gai-ning anything, is termed commensalism.

There are cardinalfish (Astrapogon stellatus) in the Caribbean that live inside the mantle cavity of giant snails of the species Lobatus gigas (former-ly Strombus gigas). A closely-related species, Astrapogon puncticulatus, lives in the shells of dead snails, similar to the behavior known from some cichlids from Lake Tanganyika.

Juvenile Sphaeramia nematoptera are really gorgeously colored....


The list of the commensal associations between cardinalfish and invertebrates is long. The Ca-ribbean species Apogon quadrisquamatus lives with anemones like clownfish do, albeit with cave- and crevice-dwelling species. The species of the genus Phaeoptyx, likewise from the Carib-bean, live with starfish and gorgonians, and the Indo-Pacific species of the genus Siphamia with the venomous Crown of Thorns Starfish and sea urchins. Some species, including the frequently imported Threadfin Cardinalfish Zoramia lepta-

cantha (formerly Apogon leptacanthus) also live among stands of coral. Only some 15 Caribbean species and around 80 Indo-Pacific species are regarded as coral fish in the strict sense, i.e. spe-cies that are always or regularly associated with coral reefs.

Cave-dwellersIn general cardinalfish can be described as fish that prefer to spend the day in caves or other shelter. Only at twilight do they venture further away from their hiding-places. At the same time cardinalfish aren’t very specialized. The two spe-cies of the genus Sphaeramia, namely the Pa-jama Cardinalfish S. nematoptera and the Orbi-culate Cardinalfish S. orbicularis, are noted for living their lives among mangroves, although they also like to live in somewhat murky water, for example in harbors. The symbiosis with lumi-nescent bacteria seen in many small cardinalfish is an adaptation to life in dark, murky water and enables them to glow in the dark (this is termed bioluminescence). Unfortunately, to the best of my knowledge these species (which belong to

Diadem sea urchin.

.... but they are also a sight to see when full grown (the species attains around 3.2 in (8 cm) long).


particular exploit the relative safety of the sho-al. Pairs form from among the groups, and retire to a shared living cave at breeding time. In the aquarium pairs of the Banggai Cardinalfish, for example, may remain together for many years and become ever more compatible in their bree-ding behavior.

In the aquarium it can also often be observed that after spawning females remain in the vicinity of brooding males. In the wild such observations are only very rarely possible for obvious reasons. In Apogon notatus at least the female remains in the living cave after spawning, while the brooding male often leaves to join a shoal of conspecifics. The female then entices another random male into the cave (he may even be a brooding male) and spawns with this new mate as soon as the opportunity arises. So marital fidelity appears to be more aquarium artifact than typical behavior - at least in cardinalfish.

the genera Siphamia and Acropoma), plus spe-cies of the genera Pempheris, Parapriacanthus, Archamia, Jaydia, and Rhabdamia, which are ca-pable of bioluminescence without symbiotic bac-teria, haven’t yet been imported. A special aqua-rium with these little fish would be a fascinating sight at night!

Cardinalfish may tolerate the strong lighting in modern reef aquariums, but don’t require it at all. For this reason they can be classified without hesitation as “energy-saving fish”, as the aquari-um lighting above a cardinalfish aquarium needs only to satisfy the requirements of the owner, it’s all the same to the fish.

Social behaviorEssentially, the majority of cardinalfish are found in large groups in the wild. The small species in

Above brooding male, below female of Zoramia leptacantha. The species grows to around 2.4 in (6 cm) long.

Reproductive behaviorAs far as is known to date all cardinalfish are paternal mouthbrooders, but obviously only a very small percentage of the cardinalfish in existence are actually so well known that any

definite statements can be made about their reproductive behavior. Even such interesting details as the question of how fertilization of the egg-ball takes place in the mouth of the male have been only inadequately studied to date.

Zoramia leptacantha is regularly imported. Like all Cardinalfish species it should be kept in a shoal.

Ostorhinchus parvulus are breathtaking dwarfs that grow to only around 1.2-1.6 in (3-4 cm) long.

The attractive Ostorhinchus margaritophorus grows somewhat larger, specifically 2.6 in (6.5 cm).


INFO BOX

The majority of freshwater cardinalfish live in Australia and New Guinea. They belong to the genus Glossamia and aren’t imported. One spe-cies of the genus Apogon - Apogon amboinen-sis, pictured here - is, however, very widespread in East Africa and South-East Asia. The photo shows a specimen from Thailand. A. amboinen-sis is actually a brackish-water fish but is often found in completely fresh water.

Apogon amboinensis is slightly reminiscent of the glassfish of the genus Parambassis popular in the aquarium, but its mouthbrooding makes it a lot more interesting behaviorally. As with the majority of cardinalfish, to the present day practi-cally nothing is known about the details of the life history of this species. It is, however, assu-med that A. amboinensis belongs to the species with relatively few, but large eggs. In that case then between 200 and 300 fry per brood can be expected from a breeding pair of this species, which grows to around 2.8 in (7 cm) long.



Ostorhinchus hartzfeldii is one of the larger car-dinalfish species with a maximum length of 4.7 in (12 cm).

Intensive observations of the spawning behavior of the King of the Mullets in the Monaco Aquarium by J. Garnaud in the 1960s were interpreted as suggesting internal fertilization, as female Cardinalfish lay their eggs at a stroke in large balls, and the males then pick up these balls within a few seconds without any act of fertilization being observed. A more probable explanation is that the male doesn’t release sperm until after he has picked up the eggs and that the striking, excited way in which the female swims around the male after he has picked up the eggs serves to enrich the water he breathes with sperm such that fertilization of the eggs can take place in his mouth (Kuwamura, 1983). Even though the hypothesis of internal fertilization in the King of the Mullets can still be found in the latest literature and is portrayed as fact, recent research instead indicates that the theory is untenable (Petersen et al. 2005), not least because male cardinalfish lack any anatomical structures that might make such internal fertilization possible.

Productive fishCardinalfish are in general very common, and are not only widely distributed but also found at high population densities. At the same time they have highly variable strategies as regards num-bers of offspring. The only 2.7-3.5 in (7-9 cm) long Apogon notatus, for example, lays egg-balls containing several thousand eggs, while at the other extreme Pterapogon kauderni, the Banggai Cardinalfish, produces only some 24 fry per spa-wning on average and 170 young per year (Mai, 2004).

The Banggai Cardinalfish also has one of the smallest natural distribution regions of any tropi-cal marine fish, and thus represents an exception in practically every respect.There are all sorts of intermediates between the-se two extremes of breeding. Ostorhinchus ruep-pellii, for example, produces relatively large and at the same time few eggs (50-280).


Apogon maculatus is one of the commonest fishes in the Caribbean. Because of its small egg numbers itshould also be readily breedable in the aquarium.


www.zoomed.com

Here is a summary of the clutch sizes published to date (after Neira, 1991): Apogon affinis, size of parent fish 2.1-3.5 in (5.5-9 cm), 21,000 eggs per egg-ball

Apogon imberbis, size of parent fish not given (the species grows to a maximum of 6 in (15 cm) long), 22,000 eggs per egg-ball

Apogon lineatus, size of parent fish 2.1-3.3 in (5.5 - 8.5 cm), 3,200 -13,250 eggs per egg-ball

Apogon maculatus, size of parent fish around 2.4 in (6 cm), 75-100 eggs per egg-ball.

Ostorhinchus rueppellii, size of parent fish 1.8-3.3 in (4.5 - 8.5 cm), 50-280 eggs per egg-ball.

Sphaeramia orbicularis, size of parent fish 2.8-3.5 in (7-9 cm), 6,100-11,700 eggs per egg-ball.

Vincentia conspersa, size of parent fish 3.7 in (9.5 cm), 150 eggs per egg-ball.In some species, for example Sphaeramia orbi-cularis, a link has been established between re-

productive behavior and the phases of the moon in the wild, but not in others. The brooding period varies from eight days (at 81-86°F (27-30 °C)) in Sphaeramia orbicularis to up to 28 days in Pterapogon kauderni.When we consider that there are actually very many species of cardinalfish and each of them probably has its own special characteristics, then there is obviously a wide field of activity availab-le to experimentally-minded aquarists with bree-ding ambitions.

Cardinalfish in the aquariumCardinalfish can without reservation be described as suitable beginners’ fish for marine aquarists. They don’t pose any especially high demands as regards water quality and are not particularly susceptible to disease. Almost all cardinalfish prefer to feed on small crustaceans and can be fed without problem on frozen foods (Mysis, Gammarus, Artemia, etc). Obviously cardinalfish will also eat small fish and shrimps that will fit into their mouths, and so care is regarded in the selection of tankmates, but corals, anemones, and all other sessile invertebrates, plus echinoderms

Cheilodipterus quinquelineatus grows to around 5.1 in (13 cm) long. Females have less yellow on the caudal peduncle.


The identification of cardinalfishes is often atricky business. Many species lookextraordinarily similar, for example thoseshown here: Ostorhinchus sealei (above) andO. chrysopomus (below).



Ostorhinchus cyanosoma grows to 2.4-3.2 in (6-8 cm) long. Females stay with “their” males after spawning, at least in the aquarium.

Apogonichthyoides pseudotaeniatus can grow up to 5.5 in (14 cm) long.

(starfish, sea urchins, etc) have nothing to fear from cardinalfish.It is best to buy a group of 8-12 specimens right from the start. As with many other perciforms, in-traspecific aggression is appreciably less in large groups than if only a few specimens are kept.

Sexual dimorphismNaturally it is essential to have individuals of both sexes for successful breeding. There are, howe-ver, only relatively few reliable sex differences in cardinalfish. As a rule males have a larger head and a larger mouth and are also somewhat larger overall than females. In the case of the Banggai Cardinalfish the form of the genital papilla has also been described as a sex difference (Mai, 2004).

It is, however, very unlikely that you won’t get both sexes if you buy 10 individuals. Pairs that form naturally from a group are also more likely to breed reliably than pairs put together arbitra-rily, or at least that is what breeders of the Bang-gai Cardinalfish say.

Life expectancyNatural life expectancy is usually linked to size in cardinalfish. The smallest species live less than a year, the King of the Mullets around five ye-ars, but fundamentally fish live a lot longer in the aquarium than in the wild. The Banggai Cardi-nalfish has been recorded as still breeding at the age of five years (Mai, 2004).

All in all, cardinalfish are ideal aquarium fish for marine aquarists and anyone who aspires to be-come one. There is still much about them to dis-cover and study, and aquarists have an important role to play in this. That includes you!

Brooding pair of Ostorhinchus cyanosoma. Male below, female above.



Male Cheilodipterus quinquelineatus.

Apogon means ”without barbels”.amboinensis means ”from (the island of) Amboi-na”.Apogonichthyoides means ”similar to Apogo-nichthys” (another fish genus).barbatulus means ”with a little beard”.Cheilodipterus means ”with a two-pronged fin”.chrysopomus means ”gold belly”.cyanosoma means ”with a blue body”.Glossamia means ”Amia with a tongue”; Amia was formerly used as a genus name for cardi-nalfish.hartzfeldii: named in honor of the collector of the type material of the species, Dr. J. Hartzfeld.imberbis means ”beardless”.kauderni: named in honor of Walter Kaudern

(1881-1942).leptacantha means “small-spined”.maculatus means ”spotted”.margaritophorus means ”pearl-bearing”.Mullus is the name used for the Mullet back in antiquity.nematoptera means ”thread-fin”notatus means ”notable, marked”.orbicularis means ”circular”.Ostorhinchus means ”bony nose”.parvulus means ”very small”pharaonis means ”of the Pharaoh(s)”.pseudotaeniatus means ”false taeniatus”.Pterapogon means ”winged Apogon”.quinquelineatus means ”with five lines”.sealei: named in honor of Alvin Seale (1871-1958).Sphaeramia means ”spherical Amia”.Zoramia: meaning unclear, literally ”Amia from Zor”.

Lexicon: Cardinalfish


Large cichlids from South America are not always the most popular of aquarium fish. Leaving aside their physical size, they like to dig, regard smaller tankmates and aquatic plants as part of their diet, and at breeding time make it abundantly clear to every other occupant of the aquarium who is cock of the roost. For this reason the majority of aquarists prefer to look at these impressive fellows at the zoo rather than at home. With one exception: Ast-ronotus ocellatus, the Velvet Cichlid or Oscar. by Wolfgang Löll

The unusual name ”Oscar” for this cichlid has become established internationally, but it

is also known as the Velvet Cichlid or Marbled Cichlid in English.

Why the Oscar is called OscarTo be honest, nobody really knows the precise answer, though it is certain that the name origina-ted in the USA. In 1936 an article by E. W. Clarke on Astronotus appeared in the hobby magazine

Oscars


The Aquarium. Clark owned a pair called Lena and Oscar. In 1949 Gene Wolfsheimer reported in The Aquarium Journal that aquarists in Cali-fornia were referring to Astronotus cichlids as Oscars (Wayne Leibel, Aquarium USA Annual 2001). It is also possible that the word Oscar is

Adult wild-colored Oscar, Astronotus ocellatus. The spots in the dorsal-fin region are typical of thespecies. All photos: Frank Schäfer

a corruption of the scientific name or of the Tupi word acara, used for all sorts of large cichlids. Tupi is the language of the aboriginal people that lived in Brazil before Europeans arrived in the Americas.


WidespreadAstronotus originate from South America, whe-re they live in the major rivers of the Paraguay, Amazon, and Orinoco drainages, as well as tho-se of the Guiana Shield. They are prized and po-pular as food fish throughout their range. Nobody knows how many species of Astronotus actually exist. The genus is, to put it politely, in need of revision. Generally speaking, only two species are recognized by science, A. ocellatus and A. crassipinnis, but a total of seven species have been described in the past. The majority are now regarded as synonyms of A. ocellatus, but in the view of some people at least this is undoubtedly incorrect.

Oscars in the aquariumThe first Oscars were exported to Europe in 1929. Because they are relatively undemanding and attractively colored they were among the favorite large cichlids that people brought back from South America. We mustn’t forget that in the past importations were made by ship and animals were usually brought back by seamen

to supplement their income. This meant that the fish were in transit from Brazil for 3-4 weeks, of-ten longer, in so-called fish cans. Although we shouldn’t underestimate the know-how of the fish transporters of those days, the fish needed a cer-tain amount of resilience to survive. Then again, the first successful exports of discus took place back then...

Large and spectacularOscars are among the largest aquarium fish nor-mally seen in the trade, and can attain a length of up to 15.8 in (40 cm). That size is in fact exceptio-nal, but can be achieved by long-lived specimens in huge aquariums. Almost all the individuals seen in the trade are captive-bred in South-East Asia. Wild-caught specimens are only very rarely offered for sale and are then always labeled as such.

Anyone with an aquarium 59 to 79 in (150 to 200 cm) in length should definitely try their hand at keeping Oscars in it. These fish can become exceptionally tame and provide their owner with a lot of enjoyment, plus they become


Wild-caught adult Oscar from Colombia. This spe-cies has not been scientifically described.


Aquarium Glaser recently imported these spec-tacular Oscars from Brazil (Rio Tapajós). They are probably Astronotus zebra PELLEGRIN, 1904.

Adult Oscar of the Red Tiger cultivated form.

more attractive with every centimeter they grow. Oscars can, however, often cause a lot of trouble in smaller aquariums, as after all, they are cichlids and defend their personal territory fairly energetically. Because Astronotus rapidly grow to 5.9-7.9 in (15-20 cm) long even in smaller aquariums, a meter-long tank is not too small for a single Oscar, with no other fish sharing the tank. For this reason it is better not to buy Oscars unless a really large aquarium is available.

Productive open-broodersOscars breed in pairs, with both male and female sharing equally in the care of eggs and fry - often more than 1000 per brood! The sexes can be told apart only with difficulty (females remain smaller and have a more pointed head profile), so the best way to obtain a pair is by growing on a group of youngsters and letting them choose their own mates. There are good reasons why Oscars are not usually bred commercially in Europe. Rea-ring the ever-voracious brood to saleable size costs more in time, electricity, and water (not to mention food) than they fetch when sold, but matters are completely different on the rare oc-casions when wild-caught specimens - such as the spectacular Zebra Oscar - are imported!

Young Oscars have completely different color-ation. This one is wild-caught, from Para, Brazil.


As with all things in life, much is possible in the terrarium hobby and it is primarily a matter of taste. The majority of reptile keepers maintain only a few individuals as they are usually inte-rested in the personalities of their pets. They are well provided with pets among the reptiles, including the bearded agamas, the Europe-an tortoises, the leopard geckos, and the corn snakes. There is copious literature available on these animals and anyone who can read won’t have any difficulties with these creatures apart from the normal vicissitudes of life. But there are also naturalists among terrarium keepers, peo-ple who like to study the life history of their pets and learn more through observing them in the terrarium, thus gaining deeper insights. Anyone who wants to take that path will find the Dwarf Girdled Lizard an ideal beginner’s reptile. These lizards do not pose any excessive demands and are relatively easy to breed.

The Dwarf Girdled Lizard

At present a small lizard, Cordylus tropi-dosternum, the Dwarf Girdled Lizard, is frequently being imported from Tanza-nia. It is ideal for the beginner with a se-rious interest in the terrarium hobby.

by Thorsten Holtmann


Male



Girdled lizards – an overview The family Cordylidae, the girdled lizards, cur-rently contains 55 species in 3-4 genera. One genus, Chamaesaura, with 3 species, contains almost legless lizards that look similar to our Eu-ropean Slow-worm. Cordylus contains 37 spe-cies. In the past Cordylus and Pseudocordylus were regarded as distinct on the basis of the scalation on the nape and dorsum, but recent authors no longer regard Pseudocordylus as a separate genus, and the species it formerly con-tained are nowadays assigned to Cordylus. And finally there is the genus Platysaurus, with 15 species.

Of the numerous species of the genus Cordylus, at present only C. tropidosternum plays a note-worthy role in the trade, while the Giant Girdled Lizard, C. giganteus, remains rare and sought-af-ter. All the many other species are practically unknown in the terrarium hobby.

The Dwarf Girdled LizardThis species is rather widespread in southern Af-rica and occurs in the south-east of Kenya and across Tanzania, northern Zambia, Katanga Pro-vince in the D.R. Congo, Malawi, Mozambique, and north-eastern Zimbabwe. The Dwarf Girdled Lizard is a steppe-dweller. Because these repti-les attain a head-body length of only around 4 in (10 cm) and a total length of 7 in (18 cm), they do not require an excessive amount of space. In contrast to almost all other lizards, the dainty Dwarf Girdled Lizards are completely peaceful among themselves. This applies even in the case of males. In fact it can even be concluded from the behavior of these lizards that they feel consi-derably happier in the company of their own kind than when they are kept singly or in pairs. They are then also appreciably less shy.

Female


Female Dwarf Girdled Lizard with newborn young-ster. Photos: F. Schäfer

The Dwarf Girdled Lizard is a livebearing lizard. This makes it particularly suitable for the begin-ner, as the most difficult part of breeding lizards is invariably providing the female with suitable places to lay her eggs that are also acceptable to the lizards.

Maintenance By day the temperature beneath the main heat source should be around 104 °F (40 °C) and about 86 °F (30 °C) throughout the terrarium, while at night the temperature can be allowed to drop to room temperature. It is important to have a cool phase of around 3 months, with around 77 °F (25 °C) by day and about 61 °F (16 °C) at night. Dwarf Girdled Lizards are exclusively in-sectivorous. Food animals should be sprinkled with a calcium-vitamin mixture. A drinking-water bowl should always be available. These lizards can also take in water via their skin.Anyone who has successfully tried Dwarf Girdled Lizards will have taken the first step along the road to becoming a terrarium keeper and may perhaps subsequently become involved with the less well-known members of the genus; he’ll have earned his terrarium stripes in any case!



Channa sp. aff. bleheri “Flame Fin”

NEW ON THE MARKET!

Hydrolycus armatus Orinoco

Once again it has been possible to import this breathtaking fish from the Rio Orinoco. Anyone interested in this species should seize the oppor-

tunity to buy it as soon as they see it offered, as it is available for only a few weeks each year.

Text & photos: Frank Schäfer


Megalamphodus sweglesi Albino

This captive-bred albino sport of this well-known tetra is now available for the very first time. Re-gardless of whether you like albinos or not, this somewhat spooky fish is more deserving of the

common name Red Phantom Tetra than the wild form, and fans of “man-made” sports will certain-ly love this new one!




L24 has been described as Pseudacanthicus pitanga

Another L-number catfish, L24, has finally recei-ved a proper scientific description: the beautiful orange-finned cactus pleco from the Rio Tocan-tins is now named Pseudacanthicus pitanga. The specific name pitanga is from the Tupi-Guarani language and means “red”, in allusion to the co-lor of its fins.The scientific paper also discusses the risks of collecting this fish for the ornamental fish indust-ry, and the author concludes that this kind of use doesn’t represent any danger to wild populations. The only real threat to Pseudacanthicus pitanga is the construction of hydroelectric dams, which change the water flow of rivers in a manner de-trimental to fish like L24 that are specialized for living in fast-flowing waters. However, because P. pitanga is very widely distributed in the Tocantins, the species is currently not endangered at all. Reference: Chamon, C. C. (2015): Pseuda-canthicus pitanga: a new species of Ancestrini (Siluriformes: Loricariidae: Hypostominae) from Rio Tocantins Basin, North Brazil. Zootaxa 3973 (2): 309-320


Polypterus delhezi

The bichirs - Polypterus - are relics of ancient times, and were already in existence 60 million years ago. The peculiarities of the bichirs inclu-de the fact that they breathe via a lung and that the pectoral fins are positioned at the end of mu-scular “stalks” that can be moved like miniature arms.

Some species of bichir become quite large - 31.5-35.4 in (80-90 cm) - but others remain much smaller. The latter include Polypterus delhezi from the Congo, which attains a maximum length of 11.8-13.8 in (30-35 cm). The species has quite a pretty pattern. P. delhezi is bred in large num-bers in Indonesia, where these ancient fish are


thought to be reminiscent of dragons and hence are popular with aquarists. Wild-caught specimens are only rarely avail-able, however, so it is good news that a recent consignment of fish from the Congo contained a number of wild-collected Polypterus delhezi. Text & photos: Frank Schäfer

Polypterus means “with many fins” (refer-ring to the numerous finlets on the back).

delhezi: named in honor of M. Delhez. Suggested common name: Barred Bichir

Lexicon:



First of all, some interesting background infor-mation on the Hornet Cichlid. The species was scientifically described by Ribbink & Lewis in 1982, under the name Melanochromis crabro. It was later transferred to the genus Pseudotro-pheus, where it still remains to the present day. P. crabro grows to around 5.9 in (15 cm) long

The cichlids of Lake Malawi enjoy consid-erable popularity among aquarists. They are extremely colorful and usually easy to keep as well as breed. Less well known, however, is the fact that some Malawi Cichlids also have amazingly interesting behavior! The Hornet Cichlid, Pseudotro-pheus crabro, is one of the most interest-ing species from the huge lake. Read all about it below. by Andreas Jung

The dark side of the HornetCichlid

in the aquarium, but in the lake remains consi-derably smaller at 3.5-4.7 in (9-12 cm). The first importations took place at around the same time as the scientific description, i.e. at the beginning of the 1980s. The first imports for the aquarium hobby were probably all from the Mbenji Islands, but the species is significantly more widely distri-buted in the southern and central parts of Lake Malawi.

The Hornet Cichlid - a chameleonThe specific name crabro is the Latin word for a hornet and refers to the normally contrasting color pattern of brown stripes on a yellow back-ground, but P. crabro is also able to change its coloration lightning-fast, becoming very dark, even almost completely black in the case of el-derly specimens. It was because of the ability to change color that P. crabro was originally known as Pseudotropheus ”Chameleo” in the trade. To the present day the reasons for this color change remain unstudied.

The ability to transform lighting-fast to dark brown or black has led to the name ”Chameleo”. Photo: Frank Schäfer

Normally Pseudotropheus crabro is bright yellow with brown bars. Photo: F. Schäfer



A cleaner fishMany of the most popular Malawi Cichlids are Aufwuchs-feeders, in other words they feed on the algae coating the rocks and any small or-ganisms this biocover contains. This has led to some aquarists being under the misapprehen-sion that all mbuna - mbuna is the name for certain rock-dwelling cichlid species - are Auf-wuchs-feeders. Pseudotropheus crabro doesn’t eat Aufwuchs; it is an opportunistic omnivore with

a focus on plankton. P. crabro is found mainly in and near caves, and by preference lives where the large catfish Bagrus meridionalis has its home. This commonplace and delicious-tasting catfish is called the Kampango or Kampoyo by the native peoples around Lake Malawi. It can grow up to 59 in (150 cm) long but around 20 in (50 cm) is a more usual size. The Hornet Cichlid acts as a cleaner fish to the Kampango, remov-

ing fish lice (Argulus africanus) from its skin. Ob-viously the populations of P. crabro cannot live on this food source alone; but the large dark cat-fish is so attractive to P. crabro that the cichlid even follows divers in black neoprene wetsuits – it apparently thinks they are catfish!

The egg robberPseudotropheus crabro doesn’t just bring bene-fits to the catfish, it also robs them of a fair amount

in return. Kampangos practice brood care, with both parents guarding the eggs and young, and fundamentally the brood care of Bagrus meredi-onalis is effective and successful. Even so, the catfish has no defense against the audacious P. crabro,which steals and eats the eggs and tiny fry of the huge Kampango without being punished.

This Kampango (Bagrus meridionalis) is acting as foster mother to young haplochromine cichlids. There is clearly an enor-mous instinctive barrier to eating fishes the same size as her own young. The young catfishes benefit from the symbiosis.

The Hornet Cichlid and a Kampango. Although the roughly 15.7-17.7 in (40-45 cm) long catfish is pro-tecting its brood, it tolerates the cleaner fish. The photo was taken at Gome Rock. Photos: Andreas Spreinat

The same specimen as above. The young catfish-es can be clearly seen.

Does the color change serve ascamouflage?It has been suggested that the Hornet Cichlid changes color so that it isn’t recognized by the Kampangos while stealing their eggs and fry. If P. crabro wishes to clean then it signals this us-ing the yellow-brown coloration and the catfish doesn’t realize that it is the same fish as the dark brown thief that eats its eggs and young. But it isn’t quite that simple. Andreas Spreinat (whom

we have to thank for the splendid underwater photos that illustrate this article) has told us that P. crabro doesn’t go to the trouble of changing color when it goes raiding. In other words, it does that in hornet coloration as well!

So it appears to be more a case of the benefit to Bagrus from the cleaning behavior of P. crabro being so great that Bagrus puts up with the loss

This Kampango (Bagrus meridionalis) is acting as foster mother to young haplochromine cichlids. There is clearly an enor-mous instinctive barrier to eating fishes the same size as her own young. The young catfishes benefit from the symbiosis.


A bunch of Pseudotropheus crabro in the natural habitat (near Penga Penga). Some individuals are yel-low-brown, others very dark in color. There is a Kampango in the background.



of eggs and young. Of course, the catfish doesn’t do so consciously, it just has an instinctive bar against eating the Hornet Cichlid. Another cich-lid species, Melanochromis baliodigma (formerly known as M. sp. ”Blotch”). also profits from this. This species prefers to feed on small fish and Ba-grus probably has difficulty telling it apart from the cleaner. However, M. baliodigma prefers to feed on the cichlid fry that use Bagrus as foster parents rather than on young catfish.

The lightning-fast color change in Pseudotro-pheus crabro thus doesn’t serve to fool the Kam-pango. The color change may serve either for intraspecific communication or simply as camou-flage against predators. As already mentioned, P. crabro prefers to live in caves, where a dark-col-ored fish will go virtually unnoticed and undoubt-edly be more difficult for predators to capture. The striking hornet-like coloration is, however, assumed by P. crabro when it wants to be recog-nized as a cleaner, as even if the Hornet Cichlid exhibits dark coloration only now and then and

for no apparent reason, then at such times it will be safer from predators, at least to some extent.

Fish lice can transmit serious, possibly fatal dis-eases to fish attacked by them. Perhaps this is the key to understanding why a large fish like Ba-grus meridionalis tolerates the theft of its eggs and young by P. crabro. The ongoing threat from Argulus is apparently really serious!

Foster parentsIt has already been mentioned that numerous young cichlids share the Bagrus nest and “mis-use” the parent Bagrus as foster parents. A study (McKaye, 1985) has shown that the survival rate of the young catfish is around 80% high-er when cichlids (usually Copadichromis pleu-rostigmoides, Ctenopharynx pictus, and Rham-phochromis sp.) are in the nest. How so? Well, the majority of predatory fish in Lake Malawi prefer young cichlids to young catfish as food. So the young catfish benefit from having young cichlids living in their nest!

The predatory Melanochromis baliodigma - here at Gome Rock - looks very similar to some of the color varia-tions in Pseudotropheus crabro.Does this fish use this fact as camouflage in order to hunt in Kampango nests?

Another cuckoo fishIt has recently been discovered that another cat-fish in Lake Malawi, the Sapuwa, Bathyclarias nyasensis - known to the local people as Bombe - acts as a brood parasite on the Kampango. The young Bathyclarias are completely accepted by the parent Kampango. This means that they are not only protected, but also fed. Female Bagrus meridionalis produce unfertilized “food eggs” to feed their young, and such eggs have been found in the stomachs of all young Bathyclarias living in Kampango nests. Kampango males also feed the young, mounting expeditions to bring back in-sects, young crabs, etc, which they expel in par-ticulate form via their gill slits and thus feed the young. Kampango nests that are home to young Bathyclarias contain very few, if any, Kampango young. It is not known whether the parent Bathy-clarias spawn over Kampango nests and their young then hatch sooner than the Kampango eggs and eat their step-siblings, or whether the Kampango nests are invaded by older Bathyclar-ias fry. One thing is certain, however: the Bathy-clarias/ Kampango relationship is a true parasite/host relationship, that acts to the detriment of the Kampangos.

And those, Dear Reader, are just a couple of sto-ries about Malawi fish. Doesn’t this demonstrate that these species have a lot more to offer than just attractive colors?

A roughly 7.9-9.9 in (20-25 cm) long Kampango. At this size these catfishes are brownish with a number of black speckles.

Bathyclarias nyasensis can grow rather large,with lengths of up to 3 feet (1 meter) known.


There are eight species of the genus Bathyclarias in Lake Malawi. B. nyasensis is the most frequent.

Bathyclarias nyasensis, the Sapuwa, practices brood parasitism on Bagrus meridionalis, the Kampango..



Because of the vast variety of species only the small colorful characins - those that don’t

normally exceed an eventual size of 4 in (10 cm) - will be discussed here. The piranhas are best reserved for experts, and the other large species are so rare and so expensive in the trade that they are maintained only by experienced specia-lists, zoological gardens, and the like, who have access to relevant specialist literature.From a zoological viewpoint the species cover-ed here are members of the families Characidae, Crenuchidae, Gasteropelecidae, and Lebiasini-dae from South America, as well as the Alestidae and Distichodontidae from Africa.

Important requirementsCharacins are popularly termed “shoaling fish”, which is, strictly speaking, only very marginal-ly correct. They are in fact social fish that so-metimes join together to form larger groups, but often also occupy very small territories that are even defended against conspecifics on a short-term basis. In practice this means that characins should be kept in groups of six or more individu-als, the upper limit being determined only by the size of the aquarium.

A large number of the species of interest to the aquarium hobby have adapted to waters that are inhospitable to other, larger fish, specifically small bodies of water with soft acid water. The chemical composition of the water is, however, of no physiological significance to characins; a Car-dinal Tetra can live just as long in medium-hard, slightly alkaline water as a conspecific kept un-der near-natural water conditions. Very good wa-ter quality, in particular as demonstrated by the density of the bacterial population in the water, is of far more importance. The majority of characins maintained in the aquarium require well-main-tained water with a low germ count. This can be achieved via efficient biological filtration, the ad-dition of humic substances using peat, Alder (Al-nus glutinosa) cones, or dead leaves (there are also suitable liquid preparations available), the

Characins

Characins is the term used for a whole set of fish families from Africa and South America that have certain anatomical fea-tures in common, but can be very different in appearance. The characins include, for example, not only the tiny Neon Tetra and its close relatives (Paracheirodon), but also the piranhas (Pygocentrus) and the African tigerfish (Hydrocynus), which can grow to more than a meter long.

by Frank Schäfer

The Cardinal Tetra (Paracheirodon axelrodi), family Characidae, is not only a characin but also one themost important of all ornamental fishes.

best plant growth possible (many aquatic plants produce antibiotic substances that have a limi-ting effect on bacterial growth), and regular parti-al water changes, which should be as extensive as possible (see below).The appropriate water temperature for long-term maintenance is generally between 72 and 79 °F (22 and 26 °C), but almost all characins can also survive temperatures of up to 86 °F (30 °C) for short periods (a few days to weeks) and almost all species will tolerate a short-term drop (a few days to weeks) to 64 °F (18 °C). In the case of species of southern provenance (Uruguay, Para-guay) the temperature can periodically drop as low as 57 °F (14 °C).

Appropriate feedingThe characins normally maintained in the aqua-rium can be characterized as omnivores with a preference for carnivore foods. They can be fed entirely without problem on all the usual types of food for ornamental fish available in the trade (i.e. dry, frozen, and live foods). Only a few larger species feed predominantly on vegetable food. If the fish are observed to consume aquatic plants then additional vegetable food (special flake foods, scalded lettuce or dandelion leaves, etc) should be provided.

Correct maintenanceCharacins are sensitive to a high germ count in the water and to high levels of nitrogenous com-pounds. For this reason regular large partial wa-ter changes are the most important element of maintenance. Ideally 1/3 - 2/3 of the water should be changed every week, refilling with conditi-oned, fresh water of the same chemistry; at the same time the difference in temperature between the new water and the aquarium water should be as small as possible and never more than 5-6 °F (2-3 °C). In aquariums with a low fish densi-ty, minimal germ population, and good biological filtration, water changes can be reduced to 1/5 of the total volume every 14 days. Longer intervals should not be employed in the long term.

Nannostomus marginatus, family Lebiasinidae, size 1.2-1.4 in (3 - 3,5 cm).

The Congo Tetra, Phenacogrammus interruptus, is the best-known member of the African characin family Ales-tidae.



In line with the natural habitat, these fish should always have access to secondary plant material. Dead leaves (of Sea Almond (Terminalia catap-pa), Beech (Fagus spp.), Oak (Quercus spp.), or Walnut (Juglans spp.)), Alder cones, or peat can be utilized, or special liquid preparations added at every water change.

Aquarium and tankmatesCharacins are active fish that need a certain amount of swimming space for their well-being. Tank length should be around 10-15 times the length of the species in question, with a width to match (i.e. 5-7.5 times fish length), to permit the fish enough room to exhibit their species-typical swimming behavior.

Many species (e.g. Neons and Cardinals (Pa-racheirodon) live near the bottom, while others (e.g. the majority of Hemigrammus and Hyphes-sobrycon species) favor the middle layers of the water, and yet others (e.g. hatchetfish (Carne-giella, Gasteropelecus and Thoracocharax) and tetras of the family Lebiasinidae (Pyrrhulina, Copeina, Copella)) live near the water’s surface. There are also bottom-dwelling characins with a reduced swim bladder (Characidium and others in South America plus Nannocharax and related genera in Africa).

An aquarium for characins should provide plenty of cover and at the same time offer open swim-ming space. Floating plants will provide an in-creased sense of security and hence well-being. A dark substrate will encourage intensified colo-ration.

Characins are usually peaceful among themsel-ves and towards other species. The occasional individual may exhibit aberrant behavior, and replacements for losses from any groups present should be obtained as quickly as possible.

Life expectancyIn the wild the majority of the small characins ra-rely enjoy a second year of life, but in captivity they can be astonishingly long-lived. Small spe-cies usually start to show the first signs of age at about three years old, medium-sized at 5-8 ye-ars, and large species can even live for decades.

SizeSmall characins with an eventual size of less than 2 in (5 cm) are sexually mature at 12-15 weeks old, and at this point will be half to three quar-

Hyphessobrycon eques, cultivated form”Minor”, family Characidae, size 1.2-1.6 in (3 - 4 cm).

Distichodus sexfasciatus, family Distichodidae.This species grows very large (9.8-15.8 in (25 - 40 cm)).


ters (depending on environmental conditions) of their eventual size. Larger species (up to 4 in (10 cm)) grow somewhat more slowly and are often not full-grown until the age of 12 months. Spe-cies that grow larger than 4 in (10 cm) usually don’t reach breeding size until their second or third year of life. Because of the large variety of species, you should always check the potential maximum size of any species that interests you before buying it.

Special detailsBecause of their bright coloration and lively be-havior, small characins are ideal fish for commu-nity aquariums. With a few exceptions, they do not practice any brood care and hence do not de-fend territory - in other words they are peaceful.

Marbled Hatchetfish, Carnegiella strigata, from the family Gasteropelecidae.

Poecilocharax weitzmani, family Crenuchidae, size: 1.2-1.6 in (3-4 cm).

www.zoomed.com


Widely distributedPelusios castaneus is one of the most widely dis-tributed turtle species in Africa. It is found along practically the entire Atlantic coast of the Dark Continent, from southern Mauretania across Se-negal via The Gambia, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroon, and the north-wes-tern part of the Central African Republic. In addi-tion, heading south from Cameroon the species inhabits an area in Equatorial Guinea, Gabon, Congo, and the DR Congo, reaching the northern part of Angola. The species also occurs on Sao Tomé, an island offshore of Gabon. There is also

The West African Mud Turtle

It is often the commonest animal species that are the least reported. Pelusios casta-neus is THE aquatic turtle of West Africa, and along with Pelomedusa subrufa the most frequently imported. by Christoph Fritz, www.reptilia24.com

an introduced population in the Caribbean, spe-cifically on the island of Guadeloupe, where in all probability the species arrived with slaves who had brought live turtles with them as a food sup-ply (these turtles are eaten to the present day, more of which anon). There is supposedly ano-ther feral population in Florida, purportedly de-rived from specimens released by a pet dealer.

Nomenclatural confusionOne reason for the relative rarity of articles in hobby magazines is undoubtedly the fact that Pelusios castaneus is frequently confused with P. subniger, which, however, shares only a relati-vely small part of the distribution of P. castaneus and in general occurs much further south and east. The two species are most easily distingu-ished by the nuchal scutes, which together are about as broad as the first vertebral scute in P. castaneus, but total only 55-85% of the width of the first vertebral scute in P. subniger. Additio-nal differences are shown very clearly at http://pelomedusoides.org, a website that can be most heartily recommended to anyone interested in Pelusios castaneus.

A Pelusios castaneus looking at the camera with interest. The species becomes very tame.

Pelusios seychellensis, not extinct....... because it never existed. At present 17-18 Pelusios species are distinguished, but DNA analysis has shown that there are probably more species than previously thought. That makes Pelusios the most species-rich of all turtle gene-ra! A word of warning is, however, in order re-garding one species that has been regarded as extinct. Many years ago, three specimens of P. castaneus were deposited in the Zoological Mu-seum in Hamburg with the collecting locality erro-neously given as ”Mahé, Seychelles”. Because of the vast distance between the Seychelles and the West African distribution of P. castaneus, the-se specimens were subsequently described as a new species, Pelusios seychellensis, by Fried-rich Siebenrock (1853-1925), in his day a leading world expert on turtles, who worked in Vienna. Since then no further specimens of this species have ever been found on Mahé and it was even-tually declared extinct. However, not long ago it proved possible to extract DNA from the dried type specimen, and this showed unequivocally that Pelusios seychellensis was P. castaneus!

HabitatThe West African Mud Turtle is extremely ad-aptable and occurs in waters of all kinds: pools, ponds, lakes, rivers - it is at home everywhere. In large parts of its distribution the waters in which it lives dry up for 6-7 months of the year, and P. castaneus spends this time buried in the subs-trate. There are also rainforest forms (such as the specimens illustrating this article) that have water available year-round. P. castaneus is also undemanding as regards feeding. It eats insects, snails, carrion, small fish, and amphibians, and sometimes also fruits and seeds. In addition the species is very fertile. Large females can easily produce two clutches of up to 18 eggs per year.

Endangered or not?Unfortunately nowadays it is almost impossible to discuss turtles without mentioning the endangered status of the species. Because of its vast distribution region and great adaptability, Pelusios castaneus shouldn’t in fact be endangered, but there have been no scientific studies of the wild populations in the major part


Habitus of an approximately 5.9 in (15 cm) long Pelusios castaneus. Note the two little barbels on the chin.All photos: Frank Schäfer


of its distribution. Little money is available for fieldwork, and hence virtually nothing is known about population trends. Scientists in Nigeria utilize a very interesting procedure: they visit markets that regularly offer “bush meat” (i.e. wild animals sold as food) for sale. This also includes turtles, of course. Unfortunately these visits have established that among the tortoises, populations of the genus Kinixys are declining significantly. Meanwhile Pelusios castaneus is still regarded as not endangered and not subject to any international trade restrictions.

Pelusios castaneus in the terrariumThe West African Mud Turtle is very easy to main-tain in the terrarium. It is undemanding and pea-ceful. Because it is a tropical animal it requires a year-round water temperature of 75-79 °F (24-26 °C), and the air should be 5-8 °F (2-4 °C) war-mer. The aqua-terrarium should not be too small (tank length 5 x shell length), as the species is

fairly lively and likes to swim. A piece of cork bark will be adequate as an everyday land area, but females require a large and above all deep land area for egg-laying. Ideally the females should be weighed regularly during the breeding season - their weight increases noticeably when they are gravid. They can then be transferred into suitably arranged accommodation, with about 11.8 in (30 cm) depth of substrate, for egg-laying. The eggs are only slightly temperature tolerant, so the in-cubation temperature should not drop below 81 °F (27 °C) or rise above 86 °F (30 °C). A tempe-rature of around 84 °F (29 °C) has proved ideal. The young hatch after 55-60 days.

Note that the individuals in the photos were im-ported from Nigeria in 2006. The two specimens - a pair - have grown from a shell length of around 2.4 in to 7 and 7.5 in (6 cm to 18 and 19 cm) during their eight years in captivity.

In terms of color, the upper side of the head of Pelusios castaneus is the most attractive part of the turtle.


http://www.usark.org


We hope you enjoyed

this issue of

© Text & Photos:Frank Schäfer / Aqualog

http://www.aqualog.de/?L=1

http://www.aqualog.de/product/deutsch/terralog/



http://www.zoomed.eu

The vivarium issue 3 vol 3 - Autumn/Winter 2015

Documents

Transcript of The vivarium issue 3 vol 3 - Autumn/Winter 2015