Anabantoidei

(Labyrinth fishes)

Class Actinopterygii

Order Perciformes

Suborder Anabantoidei

Number of families 3

Evolution and systematics

The labyrinth fishes were first recognized as a natural assemblage by Cuvier and Valenciennes in 1831, but included the Channidae (snakeheads), in addition to the current family Anabantoidei. Bleeker (1859, 1879) added the luciocephalids (pikeheads) to this group. Jordan (1923) recognized six families, including Luciocephalus and Channidae. In 1963, Liem restricted the anabantoids to the families Anabantidae, Helostomatidae, Osphronemidae, and Belontiidae, thus removing Luciocephalus and the channids. In 1983 Lauder and Liem included Luciocephalus, in its own family Luciocephalidae, again in the anabantoids as the sister group to all remaining labyrinth fishes. Britz (1994, 1995), and Britz et al. (1995) demonstrated that there are no differences between Liem's families Belontiidae and Osphronemidae and that Luciocephalus is deeply nested within Liem's belontiids. The family name Osphronemidae applies for this monophyletic assemblage. The suborder Anabantoidei is thus divided into three families, Anabantidae, Helostomatidae, and Osphronemidae. The latter family is the sister group of the former two, and it is further subdivided into the subfamilies Belontiinae (only Belontia, two spp.); Osphroneminae (only Osphronemus, four spp.); Luciocephalinae (Trichogaster, four spp.; Colisa, four spp.; Parasphaerichthys, two spp.; Ctenops, one sp.; Sphaerichthys, four spp.; Luciocephalus, one sp., one undescribed sp.); and Macropodinae (Macropodus, five spp.; Pseudosphromenus, two spp.; Malpulutta, one sp.; Parosphromenus, 10 spp., some undescribed; Trichopsis, three spp.; Betta, 43 spp., some undescribed).

The closest relatives of anabantoids appear to be the Channidae. Based on the shared presence of parasphenoid teeth, both seem to form a larger monophyletic group with the badids and the genera Nandus and Pristolepis. The only unambiguous fossil anabantoid is a complete articulated skeleton from the Miocene epoch of Sumatra, assigned to Osphronemus goramy.

Physical characteristics

Anabantoids are minute (0.78 in; 20 mm) to large (23.6 in; 60 cm) percomorph fishes with a suprabranchial organ as accessory air-breathing organ. This organ consists of the suprabranchial chamber above the gill arches that houses the modified first epibranchial, termed the labyrinth. The labyrinth may have a highly complex three-dimensional shape in some species (Anabas and Osphronemus). Both the labyrinth and the wall of the suprabranchial chamber are lined with respiratory epithelium. The suprabranchial organ obtains blood from the first two afferent branchial arteries. Blood from the organ is collected in the two anterior efferent arteries that drain into the anterior cardinal vein, not into the dorsal aorta as in other teleosts. Basioccipital with paired articular processes that permit free movement with upper pharyngeal jaws. The last two characters are shared with the channids. In most anabantoids, the lacrimal and preopercular bones bear strong serrations; in anabantids, serrations occur in the subopercle, opercle bones, and sometimes the interopercle. (The name anabantids is vernacular for the family Anabantidae; anabantoids is the vernacular name for the suborder Anabantoidei.) All species except African anabantids and Helostoma have a exoccipital foramen medial to suprabranchial chamber, greatly enhancing hearing abilities. Most species are parasphenoid toothed, a unique derived character shared with channids, badids, Nandus, and Pristolepis. The swim bladder branches off posteriorly into two elongate diverticula that reach on either side of the hemal spines to the level of the parhypural. Many species are beautifully colored, with striking sexual dimorphism and dichromatism.

Distribution

Anabantoids occur in fresh waters of sub-Saharan Africa, and south and Southeast Asia. The genera Ctenopoma, Microctenopoma, and Sandelia occur only in Africa. The latter genus is confined to the Cape region and separated by a distributional gap from the other African anabantids. Most Asian species are widely distributed, but some have a greatly restricted distribution, such as Belontia signata and Malpulutta kretseri, known only from Ceylon, or Parosphromenus deissneri, Betta miniopinna, B. schalleri, B. burdigala, and B. chloropharynx, restricted to Banka Island in Indonesia. The

northernmost distributed species is Macropodus ocellatus, from China and Korea.

Several species have been exported as food fishes or have been released accidentally from aquarium stocks to areas out-side their natural ranges.

Habitat

Numerous species of anabantoids prefer still bodies of water with abundant aquatic vegetation that are exposed to the sun, but others also live in cooler, faster, mountain streams. Most anabantoids survive in oxygen-depleted waters because of their suprabranchial organ and therefore have an advantage over most other teleosts.

Behavior

In general, anabantoids differ from most other teleosts in that they rise to the water surface at intervals to exchange the air in their suprabranchial organ. This exchange is mostly achieved by flooding the suprabranchial chamber with water that enters through the gill opening. The water pushes the air out of the chamber and the mouth, either before or upon reaching the water surface. The chamber refills with air breathed in at the surface. In a second mode, air is gulped from the surface without the prior release of air from the chamber. Engulfed air is then pressed into the chamber by swallowing movements and forces some air out of the chamber, which is released from the gill opening. The latter mode is used by adult Anabas testudineus in the water and during the overland excursions that gave the species its vernacular name, the climbing perch. In addition to the climbing perch, at least one other anabantid species, the African Ctenopoma multispinis actively leaves the water and travels over land to nearby bodies of water.

Species of the genus Colisa show a behavior reminiscent of the spitting of the archerfishes (Toxotes jaculatrix). At least in captivity, representatives of Colisa spit a series of small droplets of water toward prey items, such as small invertebrates, above the water level to wash them down to the surface where they are taken by the fish.

Species of the genus Trichopsis are known for their ability to produce croaking sounds, hence their name, croaking gourami. These sounds are produced with their pectoral fins. To create the sounds, enlarged areas of tendons from the pectoral fin musculature are moved across bony knobs on some of the pectoral fin rays. The sound is enhanced by the suprabranchial chambers, which act as resonators.

All anabantoid species, except Sandelia capensis, show a typical, and for teleosts unusual, spawning clasp in which the male wraps around the female's body. The female is then either turned to the side or upside down when eggs are released. A similar clasp is also found in channids, badids, and Nandus, but not other nandids. A reduced clasp without turning of the female is shown by some mouth-brooding anabantoids.

Feeding ecology and diet

Anabantoids are diverse in regard to their feeding ecology and diet. There are extreme filter feeders, such as Helostoma, which feeds on small pelagic invertebrates and algae that are either filtered from the water or scraped off the substrate. Other species are omnivorous (Anabas, Osphronemus, Trichogaster, and Colisa), or have a diet with an emphasis on small invertebrates (Microctenopoma, Macropodus, Betta, and Trichopsis), but others prey on larger invertebrates and small fishes (Ctenopoma and Sandelia). Luciocephalus is a highly specialized predator of small fishes. Osphronemus exodon is an exclusively herbivorous species with external jaw teeth, which feeds on leaves of terrestrial plants, grasses, fruits, and flowers.

Reproductive biology

Although anabantoids are a fairly small percomorph group, their members exhibit a great variety of reproductive modes. The primitive mode, which occurs in Anabas, Ctenopoma, and Helostoma, is the absence of parental care with the release of several thousand small (ca. 0.04 in/1 mm), buoyant eggs that float due to a single large oil globule in the egg. After hatching, larvae retain the oil globule, which during development divides into two oil vesicles to the left and right of the chorda and is used as a floating organ. All species of the genus Microctenopoma and most osphronemids build bubble nests and guard primitively buoyant eggs and larvae. Bubble nests can consist of only a few bubbles, as in the tiny cave-brooding species of Parosphromenus, or be large. Mouth brooding has evolved at least twice among anabantoids, once in the lineage Ctenops, Sphaerichthys, and Luciocephalus, and again within the genus Betta.

Unusually for anabantoids, the two species of the purely South African genus Sandelia spawn on a substratum and have adhesive eggs. In groups with parental care, the number of eggs is usually smaller than in those without care, although several thousand eggs may be spawned in some species of Microctenopoma and Trichogaster. The number of eggs may range from 40 to several hundreds in most bubble nest builders, and from 20 to 200 in the mouth brooders. Egg size ranges from 0.03 in (0.7 mm) in Microctenopoma to 0.19 in (3 mm) in Luciocephalus.

Conservation status

Three anabantoid species are categorized as Critically Endangered by the IUCN, Betta miniopinna, Betta persephone, and Betta spilotogena. Sandelia bainsii, Parosphromenus harveyi, and Betta livida are categorized as Endangered. Another seven Betta species are categorized as Vulnerable, and the two Sri Lankan species Belontia signata and Malpulutta kretseri are categorized as Lower Risk.

Significance to humans

The larger species of anabantoid fishes are important as food fishes and feature in aquaculture in various parts of Asia. Many of the smaller, colorful anabantoids are very popular hardy ornamental fishes; up to several hundred U.S. dollars have been paid for a breeding pair of the conspicuously colored fighting fish Betta macrostoma, known as the Brunei beauty.

Species accounts

List of Species

Climbing perch

Anabas testudineus

family

Anabantidae

taxonomy

Anthias testudineus Bloch, 1785, Japan. The diverse distribution and morphology of A. testudineus indicate that it may comprise more than one species.

other common names

French: Perche grimpeuse; German: Kletterfisch; Spanish: Perca trepadora.

physical characteristics

Length 9.8 in (25 cm). Robust body with wide, large head. Body shape ranges from oval and compressed to elongate and subcylindrical. Posterior edges of opercular bones, especially opercle, and subopercle, with strong spination. Without teeth on the palatine in contrast to most anabantids. Dorsal fin has 16–19 strong spines and 7–11 soft rays. Anal fin has 9–11 spines and 8–12 soft rays. Pelvic girdle without connection to pectoral girdle. Scales on the head rigidly attached to the skull bones. Scales strongly ctenoid. Lateral line interrupted at level of posterior part of spinous dorsal fin and continued two scale rows lower down to caudal peduncle. Supra-branchial organ exceptionally large and complexly folded. Coloration light beige with darker spots. A conspicuous black spot at the posterior edge of the gill cover between two prominent areas of projecting strong opercular spines and a large black ocellus on the caudal peduncle. No sexual dimorphism or dichromatism.

distribution

Widely distributed in Asia: Sri Lanka, India, Burma, Indochina, Taiwan, Sundaland (the western part of Indonesia, namely the islands of Java, Sumatra, and Kalimantan), but also introduced east of Huxley's Line (a zoogeographic distributional divide between the fauna of peninsular Southeast Asia and the Sunda islands [Sumatra, Java, and Borneo], and the fauna located on islands further to the east such as Australia, Papua New Guinea, Sulawesi, and the Philippines). This wide distributional range and the diverse physical morphology encountered indicates that more than one species is most certainly involved, but this species has not been thoroughly studied. The climbing perch has also been accidentally released in the United States.

habitat

Found in all types of fresh water, also survives in brackish water and tolerates water conditions unsuitable for most other fishes.

behavior

Well known for its behavior to travel overland, first reported more than 200 years ago; uses its spiny opercular bones and a side-to-side wriggling of the body to move itself forward on land. Obligatory air breather that drowns if kept from rising to the surface to gulp air. Can survive longer periods of drought buried in the mud of the drying water bodies.

feeding ecology and diet

Omnivorous. Feeds on macrophytic vegetation, different invertebrates, and small fish.

reproductive biology

No parental care. Typical spawning clasp lasts only a few seconds. Several thousand, buoyant, small (0.04 in; 1 mm) spherical eggs are spawned during one spawning phase. Eggs contain a single large oil globule. Hatching occurs after 24 hours at 82.4°F (28°C).

conservation status

Not listed by the IUCN.

significance to humans

A common and popular food fish in Southeast Asia. Easily transported to the markets in buckets without water as long as the skin is kept moist, and it may survive in this condition for several days.

Kissing gourami

Helostoma temminckii

family

Helostomatidae

taxonomy

Helostoma temminckii Cuvier, 1829, type locality not specified.

other common names

French: Gourami embrasseur; German: Küssender Gurami; Spanish: Gurami besador, gurami besucón.

physical characteristics

Length 9.8 in (25 cm). High body, laterally compressed. Head has large fleshy lips and several rows of spoon-shaped teeth unattached to the jaw bones. Wild-type coloration is greenish beige, with darker longitudinal lines along each scale row; a breed with uniform pink color is commonly cultivated in ponds. Adult fish has a highly specialized filter-feeding apparatus derived from modified gill rakers. Long dorsal fin with 16–18 spines and 13–16 soft rays; long anal fin with 13–15 spines and 17–19 soft rays.

Striking anatomical changes of the feeding system occur during development. Juveniles have normal conical teeth in jaws and on pharyngeal jaws. As the fishes mature, the jaw teeth are lost and substituted by a second type of spoon-shaped teeth in the fleshy lips. Lower pharyngeal jaws lose teeth completely, and their number is reduced in upper pharyngeal jaws, sitting on long bony bases so that the resulting structure resembles a brush.

distribution

Central Thailand, Malay Peninsula, Sumatra, Java, Borneo. Has been introduced to various countries as a food fish. Established populations in the Philippines, Sri Lanka, Bali, Colombia, and Florida, in the United States.

habitat

Occurs in sluggish streams, swamps, ponds, and lakes.

behavior

Exhibits "kissing" behavior, in which they protrude their fleshy lips when grazing algae or during social encounters. They may also "kiss" during aggressive behavior or courtship individuals.

feeding ecology and diet

One of the most specialized filter-feeding teleosts, filters small (even unicellular) invertebrates and algae from the water. Also scrapes off algae and other aufwuchs (plants and animals adhering to parts of rooted aquatic plants and other open surfaces) from the substrate.

reproductive biology

Exhibits typical spawning clasp. Several thousand small (0.04 in/1 mm) buoyant spherical eggs are released during one spawning phase that comprises numerous spawning bouts. Eggs with a large oil globule hatch after one day at 86°F (30°C). No parental care.

conservation status

Not listed by the IUCN.

significance to humans

A valued food fish in Southeast Asia, and popular in the aquarium trade.

Siamese fighting fish

Betta splendens

family

Osphronemidae

taxonomy

Betta splendens Regan, 1910, Menam River [= Mae Nam Chao Phraya], Thailand.

other common names

English: Betta; French: Combatant, combattant du Siam; German: Siamesischer Kampffisch; Spanish: Combatiente siamés.

physical characteristics

Up to 2.4 in (6 cm). Elongate cylindrical body, dorsal fin short with one to two spines and seven to 10 soft rays. Anal fin is long with two to five spines and 21–26 soft rays, caudal fin rounded. First soft ray of pelvic fin elongated. Sexually dimorphic; males have larger fins and a brighter coloration, females less conspicuously colored. Wild type with bluish body and blue and red fins. Two vertical iridescent marks on the opercle. Some breeds with greatly enlarged fins (sail fin) and different colors or combinations thereof, some almost completely red, blue, yellow, or black.

distribution

The original distributional range comprises the Chao Phraya basin in Thailand and northernmost Malay Peninsula (north of Isthmus of Kra). The species has been transported and released in various countries in Southeast Asia, and can now be found even in the Dominican Republic, Colombia, Brazil, and Florida, in the United States.

habitat

Tolerates a wide range of water parameters. Common in stagnant or standing water bodies with dense aquatic vegetation, especially in rice paddies and in canals. May dig into the mud when the water recedes and survive weeks in a small cocoon-like structure made of mud and probably mucus.

behavior

This species is well known for its prominently developed aggressive behavior, especially against conspecific males. Confined to small tanks, males fight until one of them is killed. In Thailand, various breeds of Betta splendens are used in popular fighting matches in which people bet on the outcome.

feeding ecology and diet

Carnivorous, feeding mostly on small aquatic invertebrates, such as zooplankton and insect larvae.

reproductive biology

The male constructs a bubble nest and aggressively defends the territory around it. Has typical spawning clasp. After the spawning claps, male and female show spawning rigor, from which the male recovers earlier (after 4 s) than the female (after about 20 s). Up to 400 spherical eggs with a diameter of 0.04 in–0.05 in (1–1.4 mm) are laid per spawning sequence. They contain no oil globule and sink toward the bottom. While eggs are sinking they are collected by the male, later joined by the female, and stored in the nest. Hatching takes place after 32 to 35 hours at 84.2°F (29°C). Larvae swim free on the fourth day.

conservation status

Not listed by the IUCN.

significance to humans

Very popular aquarium fish. Because of its hardy nature, often among the first species of freshwater fishes kept by beginners to the aquarium hobby. Of no interest to fisheries due to its small size.

Pikehead

Luciocephalus pulcher

family

Osphronemidae

taxonomy

Diplopterus pulcher Gray, 1831, type locality not specified.

other common names

German: Hechtkopf; Spanish: Cabeza de lucio.

physical characteristics

Length 6 in (15 cm). Elongate, with large head and highly protrusible upper jaws. Labyrinth simple. Has separate endoskeletal ossification in front of basihyal, erroneously termed "gular element" by some authors. Caudal fin is rounded, dorsal fin is short with nine to 11 soft rays, anal fin with a median incisure and 18–19 soft rays, pelvic fin with filamentously elongate first soft ray extending to the end of the body. Color is light beige with longitudinal dark brown bands. There are several transverse stripes in the caudal fin that may be broken up into series of spots. A second, undescribed species from Sumatra and Borneo has numerous green iridescent spots along the body.

distribution

Malay Peninsula, Sumatra, and Borneo.

habitat

Smaller streams with acidic to highly acidic (down to a pH of 3.5) water; often caught among aquatic vegetation.

behavior

The pikehead can protrude its upper jaw to about 33% of the head length, which is quite exceptional among teleosts. In captivity usually remains hidden among vegetation, from where it moves slowly toward prey. At a certain distance of around 3.9 in (10 cm), it makes a sudden rapid lunge (with a peak velocity of 150 cm/s⁻¹ and a duration of 0.03 sec.) to surround the prey by protruding its upper jaws and expanding its huge mouth cavity. Suction seems to play only a minor role in capturing the prey.

feeding ecology and diet

Appears to feed exclusively on small fishes.

reproductive biology

Mouth brooder with male parental care. Male defends territory around spawning site. Displays conspicuous sexually dichromatic coloration only during courtship and spawning. Mating with a reduced spawning clasp takes place at the bottom. All eggs are released during a single spawning bout, sink to the bottom, and are taken up into the male's mouth. The male mouth broods up to 150 eggs with a diameter of around 0.12 in (3 mm) for about four weeks. Eggs are pear-shaped, with a striking pattern of parallel surface ridges leading toward the micropyle (a preformed opening, the only place where sperm can enter the egg), where the ridges end in a counterclockwise spiral. This unique surface pattern also occurs in the genera Parasphaerichthys, Ctenops, and Sphaerichthys, demonstrating the close relationship of the four groups. Egg surface pattern may represent a sperm guiding device to enhance fertilization success. Upon release from the male's mouth, young pike-heads already measure 0.6 in (1.5 cm) long.

conservation status

The species is not threatened or endangered, but may suffer in the future from habitat destruction.

significance to humans

Ornamental fish for specialized hobbyists.

Giant gourami

Osphronemus goramy

family

Osphronemidae

taxonomy

Osphronemus goramy Lacepéde, 1801, Mauritius; China; Jakarta [Batavia], Java, Indonesia.

other common names

French: Gourami géant; German: Riesengurami; Spanish: Gurami gigante, gurami comestible.

physical characteristics

Largest species of anabantoids; up to 23.6 in (60 cm) and 19.8 lb (9 kg). High body, laterally compressed. Lateral line not interrupted and nearly straight. Dorsal fin has 11–14 spines and 12–14 soft rays. Anal fin has 10–11 spines and 20–23 soft rays. First soft ray of pelvic fin is very long, extending beyond caudal fin. Labyrinth highly complex in the adult, with the numerous folds supported by bony lamellae. Large males with prominent hump on the head. Juveniles have eight to 10 dark vertical bars and a conspicuous eyelike spot above the anal fin. Adults drab, grayish, olivaceous above and silvery or yellowish below in both sexes; no sexual dichromatism.

distribution

The species has been introduced in various areas outside of its natural range. Its original distribution probably comprised Thailand, the Malay Peninsula, Sumatra, Borneo, and Java. It now has established populations in India, Sri Lanka, Philippines, West Papua, Papua New Guinea, Madagascar, New Caledonia, and Colombia.

habitat

Occurs in swamps, lakes, and medium-to-large rivers. May also tolerate brackish water conditions.

behavior

Nothing is known about the behavior of the giant gourami in the wild.

feeding ecology and diet

The giant gourami is omnivorous, feeding on plants, smaller vertebrates, invertebrates, and even dead animals.

reproductive biology

Reaches maturity after the fourth year. The male builds a spherical to oval nest 11.8 in (30 cm) long, 7.9 in (20 cm) wide, and 3.9 in (10 cm) deep, which resembles a bird's nest, close to or below the water surface using mainly plant material. Nest building takes eight to 10 days. Eggs are deposited in the nest, and guarded by the male and female, and fanned through movements of the pectoral fins. The yellowish eggs are around 0.11 in (2.7 mm) in diameter and contain a large oil globule that makes them buoyant. Eggs may number more than 1,500 per nest. Hatching occurs after 10 days. Newly hatched fry measure 0.24–0.35 in (6–9 mm). Yolk sac is resorbed at around 15 days. After four months a length of 3.9 in (10 cm) may be reached.

conservation status

Not listed by the IUCN.

significance to humans

A valued, common, and delicious food fish, eaten steamed, fried or baked. It has been introduced into more than 20 countries all over the world, and is important in aquaculture in tropical Asia.

Pearl gourami

Trichogaster leeri

family

Osphronemidae

taxonomy

Trichopus leeri Bleeker, 1852, Sumatra.

other common names

English: Diamond gourami, lace gourami, mosaic gourami; French: Gourami mosaïque, gourami perlé; German: Mosaikfadenfisch; Spanish: Gurami perla, Gurami mosáico.

physical characteristics

Length 4.7 in (12 cm). Body laterally compressed with short dorsal fin of 5–7 fin spines and 8–10 soft rays; long anal fin with 12–14 spines and 25–30 soft rays. Pelvic fins with an extremely prolonged first soft ray behind the spine, followed by four short soft rays. This pelvic filament reaches up to two-thirds of the fish's total length, is highly movable in all three dimensions, and is used as an organ of taste because its surface is covered with numerous taste buds. A tactile function has also been demonstrated. Males can be distinguished from females by the posterior rays of the soft dorsal and soft anal fin being prolonged and projecting beyond the fin membrane. Coloration of the body consists of a grayish background, with numerous bright white spots all over the body and fins (hence the name "pearl" gourami), a black midlateral stripe that extends from the snout to the caudal peduncle, and a black spot at the base of the caudal fin. Males have bright nuptial coloration, especially when sexually active.

distribution

Freshwaters of Thailand, peninsular Malaysia, Sumatra, and Borneo.

habitat

Smaller or larger forest streams, usually with slightly acidic water.

behavior

Nothing is known about the behavior of the pearl gourami in the wild.

feeding ecology and diet

No field data on gut contents is available, but judging from the small mouth and the numerous gill rakers, feeds on small aquatic invertebrates.

reproductive biology

The onset of a reproductive period is characterized by an increasing aggressiveness of the male and the establishment of a breeding territory in which it builds a foam nest. Parts of aquatic vegetation or detritus may be incorporated into the foam mass. The foam nest is built from air gulped in at the surface and released as foam-coated bubbles below the nesting site, from either the mouth or the opercular cleft. The male's nuptial coloration is bright orange on the throat, pelvic filament, and anterior anal fin, with numerous bright white spots on the body and fins. Spawning takes place below the nest. The typical spawning clasp is performed. Eggs are usually released when the female's genital opening points to the nest. Up to 135 eggs are released during each bout of spawning, with up to 1,000 eggs per spawning sequence. A short phase (2–10 seconds) of spawning rigor follows egg release, during which the male and female remain motionless in their clasp. Eggs contain a large oil globule that renders them buoyant. Floating eggs are collected by the male and stored in the nest. Hatching occurs after 24 hours at 84.2°F (29°C). Free swimming is achieved after two to three days. The pearl gourami exhibits male parental care.

conservation status

Not listed by the IUCN.

significance to humans

Consumed as a food fish and used in aquaculture. A common and popular aquarium fish.

Resources

Books

Cuvier, G., and A. Valenciennes. Histoire naturelle des poisons, Vol. 7. Paris/Strasbourg: Levrault, 1831.

Fuller, P. L., L. G. Nico, and J. D. Williams. Nonindigenous Fishes Introduced into Inland Waters of the United States. Bethesda, MD: American Fisheries Society, Special Publication 27, 1999.

Kottelat, M., A. J. Whitten, S. N. Kartikasari, and S. Wirjoatmodjo. Freshwater Fishes of Western Indonesia and Sulawesi. Jakarta: Periplus Editions, 1993.

Vierke, J. Labyrinthfische und verwandte Arten. Wuppertal-Elberfeld, Germany: Engelbert Pfriem Verlag, 1978.

Periodicals

Bleeker, P. "Memoires sur les poissons á pharyngiens labyrinthiformes de l'Inde archipelagique." Natuurk. Verh. Akad. Amsterdam. 19 (1879): 1–56.

——. "Over de platsing in het stelsel van de Luciocephaloiden." Natuurk. Tijdschr. Nederl. Ind. 20 (1859): 395–397.

Britz, R. "Ablaichverhalten und Maulbrutpflege bei Luciocephalus pulcher." Aquar. Terr. Ztschr. 47 (1994): 790–795.

——. "Egg Surface Structure and Larval Cement Glands in Nandid and Badid Fishes (Teleostei, Percomorpha), with Remarks on Phylogeny and Zoogeography." American Museum Novitates 3195 (1997): 1–17.

——. "The Genus Betta—Monophyly and Intrarelationships, with Remarks on the Subfamilies Macropodinae and Luciocephalinae (Teleostei: Osphronemidae)." Ichthyological Exploration of Freshwaters 12 (2001): 305–318.

——. "Ontogenetic Features of Luciocephalus (Perciformes, Anabantoidei) with a Revised Hypothesis of Anabantoid Intrarelationships." Zoological Journal of the Linnean Society 112 (1994): 491–508.

Britz, R., and J. A. Cambray. "Structure of Egg Surfaces and Attachment Organs in Anabantids." Ichthyological Exploration of Freshwaters 12 (2001): 267–288.

Britz, R., M. Kokoscha, and R. Riehl. "The Anabantoid Genera Ctenops, Luciocephalus, Parasphaerichthys, and Sphaerichthys (Teleostei: Perciformes) as a Monophyletic Group: Evidence from Egg Surface Structure and Reproductive Behavior." Japanese Journal of Ichthyology 42(1995): 71–79.

Hall, D. D., and R. J. Miller. "A Qualitative Study of Courtship and Reproductive Behavior in the Pearl Gourami, Trichogaster leeri." Behaviour 32 (1991): 70–84.

Jordan, D. S. "A Classification of Fishes Including Families and Genera as far as Known." Stanford Univ. Publ., Univ. Ser., Biol. Sci. 3 (1923): 77–243.

Kratochvil, H. "Beiträge zur Lautbiologie der Anabantoidei— Bau, Funktion und Entwicklung von lauterzeugenden Systemen." Zool. Jb. Physiol. 89 (1985): 203–255.

Lauder, G. V., and K. F. Liem. "The Evolution and Interrelationships of the Actinopterygian Fishes." Bulletin of the Museum for Comparative Zoology 150 (1983): 95–197.

——. "Prey Capture by Luciocephalus pulcher: Implications for Models of Jaw Protrusion in Teleost Fishes." Environmental Biology of Fishes 6 (1981): 257–268.

Liem, K. F. "The Comparative Osteology and Phylogeny of the Anabantoidei." Illinois Biological Monograph 30 (1963): 1–149.

Peters, H. M. "On the Mechanism of Air Ventilation in Anabantoids (Pisces: Teleostei)." Zoomorphology 89 (1978): 93–123.

Roberts, T. "Osphronemus exodon, a New Species of Giant Gouramy with Extraordinary Dentition from the Mekong." Natural History Bulletin of the Siam Society 42 (1994): 67–77.

——. "Systematic Revision of the Southeast Asian Anabantoid Fish Genus Osphronemus, with Descriptions of Two New Species." Ichthyological Exploration of Freshwaters 2(1992): 351–360.

Roxas, H. A., and A. F. Umali. "Fresh-Water Fish Farming in the Philippines." Philippine Journal of Science 63 (1937): 433–468.

Sanders, M. "Die fossilen Fische der alttertiären

Süsswasserablagerungen aus Mittel-Sumatra." Verh. Geol.Mijnbouw. Genootsch. Nderl. Kol. Geol. Ser., D. XI, 1ste St.(1937): 1–144.

Vierke, J. "Beiträge zur Ethologie und Phylogenie der Familie Belontiidae (Anabantoidei, Pisces)." Zeitschrift für Tierpsychologie 38 (1975): 163–199.

——. "Brutpflegestrategien bei Belontiiden (Pisces, Anabantoidei)." Bonn. Zool. Beitr. 42 (1991): 299–324.

Weber, H. "Die Sinnesfunktion der freien Bauchflossenstrahlen der Labyrinthfische (Anabantidae) und ihr Zusammenwirken mit den Augen." Ztschr. Vergl. Physiol. 47 (1963): 77–110.

Organizations

California Academy of Sciences. 55 Concourse Drive, Golden Gate Park, San Francisco, CA 94118-4599 USA. Phone:(415) 750-7047. Fax: (415) 750-7148. E-mail: info@ calacademy.org Web site: <http://www.calacademy.org>

Food and Agriculture Organization of the United Nations (FAO) Fisheries. Viale delle Terme di Caracalla, Rome, 00100 Italy. Phone: 39 (06) 5705 1. Fax: 39 (06) 5705 3152. E-mail: [email protected] Web site: <http://www.fao.org/>

Ralf Britz, PhD