Gonorynchiformes and ostariophysan relationships dating

gonorynchiformes and ostariophysan relationships dating

bucaescort.info: Gonorynchiformes and Ostariophysan Relationships: A Publisher: Science Publishers; Publishing date: ; Language: English. Cypriniformes (carps and minnows), Characiformes (tetras and their allies), Siluriformes to compile one of the most data-rich phylogenies of fishes to date. relationships among ostariophysan fishes, focusing on the monophyly of the. Jun 22, Although this novel relationship did not receive strong statistical support, . designation of the ostariophysans (Otophysi + Gonorynchiformes) as in the MCMCTREE program in PAML b [63] was used for dating analysis.

Gonorynchus species are thought to breed in deep water. The young are transparent and have a long pelagic postlarval stage. Not until the fish reach a standard length of about 3. This long pelagic stage in their life cycle allows for the wide dispersal of juveniles. Little is known about the habitat and ecology of the African kneriids.

gonorynchiformes and ostariophysan relationships dating

Phractolaemus is thought to inhabit quiet, shaded waters and to be an epiphytic feeder. It also has a gas bladder that is divided into many alveoli, enabling it to breathe atmospheric air. Like Gonorynchus, Cromeria is found near sandy riverbanks and apparently spends much of its time buried in the sand.

The habitat of Cromeria is quite different from that of Grasseichthys, in that it is found further north in more arid environments.

gonorynchiformes and ostariophysan relationships dating

Grasseichthys inhabits forested areas farther south. Behavior Chanos is a schooling species, both as a juvenile and as an adult. Collection data for Gonorynchus, however, suggests that this species is solitary. A solitary behavior is also inferred from collection data for Phractolaemus. Feeding ecology and diet Feeding ecology seems to be variable, in that only the gonorynchids have teeth and are known to eat crustaceans. Chanos, like Phractolaemus, has a well-developed epibranchial organ and consumes planktonic prey, most often plant material.

Reproductive biology All gonorynchiform species are oviparous, i. A variety of egg types exists. Chanos and Gonorynchus produce pelagic eggs, whereas Kneria is thought to produce demersal eggs.

Sexual dimorphism is clearly evident in Kneria and Phractolaemus. In all Kneria species, adult males develop a characteristic opercular apparatus on the side of the head. Male fishes have been observed swimming attached to females during courtship and mating. By doing this, the male is in close proximity to the female during egg production.

In Phractolaemus, large thickened keratinized breeding tubercles form on the head and along the sides of adult males. Although the presence of breeding tubercles is characteristic of ostariophysans, tubercules are particularly well developed in Phractolaemus.

Gonorynchiformes

However, the South African government has designated at least one Kneria species as endangered, and the specialized requirements and extremely limited ranges of other species of Kneria and Parakneria render them vulnerable to the degradation of their habitats by humans. Significance to humans The milkfish is commercially farmed in Southeast Asia. These fishes feature in an extensive aquiculture industry in the Philippines and in Indonesia, where the young are caught close to shore and then reared in coastal ponds.

The milkfish is also the subject of a targeted fishery throughout its extensive range.

Gonorynchiformes (Milkfish and Relatives) | bucaescort.info

Results Partitioned maximum likelihood analysis based on unambiguously aligned sequences bp confidently recovered the monophyly of Otophysi and the two constituent subgroups Cypriniformes and Characiphysi. The latter clade comprised three orders Gymnotiformes, Characiformes, Siluriformesand Gymnotiformes was sister to the latter two groups.

One of the two suborders in Characiformes Characoidei was more closely related to Siluriformes than to its own suborder Citharinoideirendering the characiforms paraphyletic.

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Although this novel relationship did not receive strong statistical support, it was supported by analyzing independent nuclear markers. A relaxed molecular clock Bayesian analysis of the divergence times and reconstruction of ancestral habitats on the timetree suggest a Pangaean origin and Mesozoic radiation of otophysans.

Conclusions The present timetree demonstrates that survival of the ancestral lineages through the two consecutive mass extinctions on Pangaea, and subsequent radiations during the Jurassic through early Cretaceous shaped the modern familial diversity of otophysans. This evolutionary scenario is consistent with recent arguments based on biogeographic inferences and molecular divergence time estimates.

No fossil otophysan, however, has been recorded before the Albian, the early Cretaceous Ma, creating an over million year time span without fossil evidence.

Gosline was the first ichthyologist to unite all gonorynchiform families The teleostean fish order Gonorynchiformes Go- into a single order, the Gonorynchiformes, al- norynchus as spelt by Scopoli insuperor- though he was not completely convinced of the der Ostariophysi, consists of an ancient and mor- monophyly of the order and gave no diagnostic phologically diverse assemblage of fossil and li- characters for the group.

He simply put t h e m to- ving fishes with a widespread geographic distri- gether on the base of overall resemblances. The first significant study on the phylogenetic relationships of the Gonorynchiformes was t h a t The systematic placement of the order Gonoryn- of Greenwood et al.

They defined the Go- chiformes Berg within the Teleostei has norynchiformes as a monophyletic order, and been debated for a long time. Various gonoryn- provided characters to support the grouping. The first formal classification of the Cromeria, Grasseichthys, Kneria, Parakneria, and Gonorynchiformes within the Ostariophysi was Phractolaemus.

This rela- considered as preliminar. All of these generea are included in the present analysis. Patterson and Derived character information was analyzed by Gayet have dealt with the phylogenetic re- outgroup rooting, Deltran optimization, and the lationships of Gonorynchiformes, but did not ac- branch and bound version of PAUP version 3.

The Hennig 86 version 1. Charac- tionships by means of cladistic analyses were ters were optimized using a character description those by Poyato-Ariza and Grande This Both authors included fossil and living taxa, the program generates lists of character state trans- former focused on chanids, and the latter focused formations from the output produced by Hennig on gonorynchoids.