Transcript labroidei
Labroidei Omar Sinno Michelle Harris Labroidei Class: Actinopterygii Order: Perciformes Suborder: Labroidei 4 Families within Suborder Labroidei • Cichlidae •Embiotocidae •Pomacentridae •Labridae •Includes the scarid and odacids, although many argue that they are separate families Labroidei Suborder includes extremely speciose and widely inhabited species. Tropical and Temperate marines species Reefs, kelp beds, surf zones and tide pools Tropical with few temperate freshwater species Lakes, sluggish rivers and fast streams Few species found in brackish water Pharyngeal Jaw : Uniting the Labroidei Fused fifth ceratobranchials with teeth Muscle “sling” suspending the lower pharyngeal jaw from the skull Articulation between the upper pharyngeal jaws and the base of the skull without intervening muscle Undivided sheet of sphincter esophagi muscle Diversification of jaw structures integral to diet choice and speciation of cichlids. Family Cichlidae Generally tropical freshwater, however few found in brackish waters. Nearly all species endemic to African rift Lakes. Other endemic species found in North America, South America and the Middle East. However, introductions have made them worldwide. Family Cichlidae Non-continuous lateral line and single nostril on each side. Average 12-15 inches in length but some species up to a meter long. Several different body shapes: Disc Tubular Stream-lined Family Cichlidae Diversification of mouth, jaw and teeth allow cichlids to eat a wide variety of food. Mollusks, algae, insects, zooplankton, other fish, detris, plants and scales. Predation styles include both ambush and openpursuit. Caprichromis rams head of mouth-brooding females, making her spit out eggs. Caprichromis then eats the fry. Nimbochrmois and Parachromis play dead to lure in small fish. Family Cichlidae Very Territorial- Levels of territoriality is diverse Feeding (one of few f.w. spp) or Mating territoriality Can communicate Visual- color change may signify aggression, dominance, individuality Tactile- “mouth fighting” Chemical- distinguishing fry Acoustic http://www.youtube.com/watch?v=j7Rc8xP03B4 Family Cichlidae Invasive Cichlids Cichlids have been introduced by aquaria trade 1300 aquarium species! California – Rio Grande Cichlid Hawaii – Jewel Cichlid Florida – Mayan Cichlid Australia – Pearl Cichlid Game Fishing Peacock Bass Biocontrol Food Egypt: Delicious Tilapia Uganda: Nile Perch Cichlidae: Breeding Methods of mating diverse as well Monogamy Courtship rituals and parental care common Polygynous Male or female territoriality Polygynandrous “Lekking” (“To play” in Swedish) Congregation of 5,000-50,000 males Males build nests inshore or in open waters Females come to lay eggs in nests Extended Family model Colonization of related individuals with dominant male Cichlinds displaying Lekking Family Cichlidae Two models of Reproduction Mouth-Brooding Most polygynous, monogamous and sexually dimorphic Females and Males may mouth-brood Substrate-Brooding Fertilized eggs adhered to substrate and guarded by parents until hatched. Parents tend to be monogamous or sexually monomorphic. Sensory Systems and Speciation Cichlid coloration and vision supports that geographic isolation not necessary for speciation in Cichlids. Mutations and adaptations in vision allows different cichlid species to inhabit different levels in the water column. Fish have adapted to best respond to certain colors that correspond to differences in color in varying depths. Conservation of Cichlidae 43 species extinct Small habitats in endemic locations make native species vulnerable to extinctions Introduction of Nile Perch to Lake Victoria as food source has decimated cichlid populations. Cichlids-Speciation There are a number of hypotheses as to why the cichlids are so diverse Lake Victoria flowed over into smaller surrounding lakes allowing the cichlids to inhabit the smaller lakes. When the water recedes, the fish in the smaller lakes are isolated from the rest of the population leading to speciation. When Lake Victoria floods again, some of the fish swim back from the small lake into Lake Victoria. Other hypotheses theorize that sympatric processes within the lake caused divergence Cichlids-Speciation So there is a large number of species, but how fast did they diverge? There are 900 species in African rift lakes. 12,400 years ago, Lake Victoria was a marsh. This would indicate an extremely fast pace for speciation However, molecular clock data calculated using an assumed 5.6 percent divergence in DNA sequence every million years came up with the conclusion that Lake Victoria cichlids began evolving 100,000 to 200,000 years ago. This indicates that cichlids diverged after the break up of Gondwanaland. This is supported by the number of cichlids in South America. They migrated between Africa & South America when the two were connected as Gondwanaland. Cichlid Sympatric Speciation Embiotocidae Surfperches Inhabit marine waters, typically kelp beds, rocky reefs, and tidal zones Some species eat zooplankton, while others eat invertebrates The only family of vivparous in Labroidei Pomacentridae Includes damselfish and clownfish Damselfish Resides in tropical marine waters, typically in shallow areas close to coral reefs Highly territorial Guard a small patch of algae in a symbiotic relationship The damselfish tend their algae like a garden They strategically feed on certain areas so as not to deplete the algae Viciously attack any fish trying to steal a bite Males court females from their patch. If successful, they also guard the eggs Clownfish http://www.youtube.com/watch?v=bZ1KDf3OqU Live in anemones in tropical marine waters Why don’t the anemones sting the clownfish and inject them with neurotoxins? The clownfish have a sugar based mucous rather than protein so the anemone does not recognize it as food Their coevolution has led to the clownfish’s immunity to the neurotoxin Clownfish Again this is a symbiotic relationship The anemone protects the clownfish from predators The clownfish eats matter off the anemone that could potentially be harmful The clownfish also provide nutrients for the anemone through their fecal matter Clownfish are monogamous in the Christian sense, til death do they part Clownfish groups are typically comprised of a breeding pair and some pre-pubescent males When the female dies, the dominant male becomes the female (protandrous hermaphrodites) Labridae The wrasses Includes at least 500 species Inhabit shallow, tropical marine waters, typically close to coral reefs but can range to colder waters Wrasses are colorful and sexually dimorphic Originally born as a mix of females and males The dominant males and females become the breeding males (protogynous hermaphrodites) The submissive males become female mimics, but do not become females The submissive females remain females Labridae Some species also participate in a symbiotic relationship: the famed cleaner fish Other fish swim to a group of wrasses and usually give a signal: open their mouth or orient themselves vertically The wrasses come and clean the parasites off of the fish The wrasses even make house calls to shy fish Occasionally there are cheater wrasses who eat protective mucous or healthy tissue The “clientele” fish rarely eat the wrasses due to the enormous benefit of being cleaned of all of their potentially deadly parasites Odacidae This family includes a mere 12 species Their habitat is the coastal waters off Australia and New Zealand Body is long and slender like the wrasse Teeth are fused together like in the parrotfish Scaridae Parrotfish Inhabit shallow, tropical marine waters, typically around coral reefs Typically one male has a harem of females When the male dies, the dominant female becomes the male (again, protogynous hermaphrodites) Produce pelagic eggs (buoyant eggs, if you forgot) Scaridae http://www.arkive.org/humpheadparrotfish/bolbometopon-muricatum/video-08.html So aptly named because of their fused to teeth which look like a bird’s beak They feed on algal fronds and pieces of dead coral How do they eat coral, you ask Massive pharyngeal teeth that grinds up the dead coral They eat algal particles and live coral polyps Fun Fact! The sand that you laid on while you tanned in the Caribbean is parrotfish fecal matter Conservation The main source of endangerment for these species is the depletion of the coral reefs There are many factors Global warming Coral bleaching Coral acidification due to high CO2 Coral disease Coral mining Pollution Review questions What is the main hypothesis for Cichlid speciation and what is the reasoning behind the accepted molecular clock? What are the benefits that clownfish and anemone receive from their symbiotic relationship? Which families are protogynous hermaphrodites and which are protandrous hermaphrodites Think, what are some specific advantages to the damselfish gardening algae? What is “Lekking”? Why has the Nile Perch been introduced to the Lake Victoria region and what effect does it have to native cichlid species? What are the advantages and disadvantages to the two types of brooding. What types of water bodies would you think tubular, disc and stream-lined cichlids inhabit?