Sociedad Española de Killis, S.E.K.
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Introduction, systematics and anatomic
Killifish or Ciprinodóntidos oviparous live on all continents, but are absent from Oceania, North America and northwestern Asia. The distribution is essentially tropics, but regions of moderate or cold climates also have several species Aphanius iberus , Fundulus diaphanus , Megalebias holmbergi , for example).
These fish belong to the Order Atheriniformes, Cyprinodontidae family. The Order Atheriniformes (Greenwood et al, 1966), are a very common fish in the aquarium, as poeciliids (viviparous fish: Guppies, Mollies, Xiphos), the Aterínidos Australia and Asia (Melanotaenia and Telmaterina), the Anablépidos (Anableps) of eyes with four pupils, and totally blind cave fish of the genus Amblyopsis. Trunk systematically correspond to Vertebrata, characterized by having spine, in this case is called spine, this is a feature in which we Killis killífilos match. But from here the differences begin, because they belong to the class Osteichthyes, ie fish whose skeleton is composed of true bone unlike sharks, rays and chimeras that possess cartilage.
Killifish are bony fish are true, their bones are fully ossified bones. Superorder standing at Teleosts, possessing characteristic odd vomer bone located in the middle position of the base of the cranium (see illustration), regresses and parietal bones separated by the supraoccipital bone.
Vertebrae are monospóndilas (have a body or main disk like us humans) and anficélicas, ie its basic has a spinal vertebra above and below in the opposite position. The tail is usually homocerca, or forked in the two arms are equal, with the caudal vertebrae, forming a urostilo (welding of them forming a single bone in the form of hammer away where the caudal fin rays) . Hypural bones are fused. They have small scales elasmoides ie, composed of dentine, the same material that makes our teeth, which is a modern character or evolutionarily advanced. This finding is of importance when interpreting the origin of the fry are born unable to swim properly, which we call "rampant".
Fin rays are soft with a tendency to stiffness, especially in the early radios.
Following the systematic of the suborder have Ciprinodontidei that although similar in name to the Cyprinids, pharyngeal bones are always jagged, which does not occur in many cyprinids. They have a small mouth and upper jaw protractile with premaxillary bone of small size as previously discussed. No teeth on the palatine bones. In the pectoral girdle and missing the mesocoracoides metapterigoideo, but a metacleitro. The ribs are embedded in parapophysis robust (small bumps side of the vertebral disc). They have from 24 to 53 vertebrae, fin rays are always soft and the caudal fin rounded or straight. And to end the systematic science, belong to the family of Ciprinodóntidos whose distinguishing feature over the other close family, that of the poeciliids, is that they reproduce by laying eggs, not being viviparous. The presence of copulatory organ is not exclusive poeciliids as Cynop. functional possesses imelanotaenia by internal fertilization.