Crossword clues for agnatha
The Collaborative International Dictionary
Agnatha \Agnatha\ n. a class of eel-shaped chordates with a cartilaginous skeleton lacking jaws, scales, and pelvic fins. Among these are the lampreys and hagfishes. There are some extinct forms.
Syn: class Agnatha.
Wiktionary
n. An agnathan.
WordNet
Wikipedia
Agnatha ( Greek, "no jaws") is a superclass of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present ( cyclostomes) and extinct ( conodonts and ostracoderms) species. The group excludes all vertebrates with jaws, known as gnathostomes.
The agnathans as a whole are paraphyletic, because most extinct agnathans belong to the stem group of gnathostomes. Recent molecular data, both from rRNA and from mtDNA as well as embryological data strongly supports the hypothesis that living agnathans, the cyclostomes, are monophyletic.
The oldest fossil agnathans appeared in the Cambrian, and two groups still survive today: the lampreys and the hagfish, comprising about 120 species in total. Hagfish are considered members of the subphylum Vertebrata, because they secondarily lost vertebrae; before this event was inferred from molecular and developmental data, the group Craniata was created by Linnaeus (and is still sometimes used as a strictly morphological descriptor) to reference hagfish plus vertebrates. In addition to the absence of jaws, modern agnathans are characterised by absence of paired fins; the presence of a notochord both in larvae and adults; and seven or more paired gill pouches. Lampreys have a light sensitive pineal eye (homologous to the pineal gland in mammals). All living and most extinct Agnatha do not have an identifiable stomach or any appendages. Fertilization and development are both external. There is no parental care in the Agnatha class. The Agnatha are ectothermic or cold blooded, with a cartilaginous skeleton, and the heart contains 2 chambers.
While a few scientists still regard the living agnathans as only superficially similar, and argue that many of these similarities are probably shared basal characteristics of ancient vertebrates, recent classifications clearly place hagfish (the Myxini or Hyperotreti), with the lampreys (Hyperoartii) as being more closely related to each other than either is to the jawed fishes.
Usage examples of "agnatha".
Ambassador Agnatha, of course, required that his tank be properly installed in his cabin.
He realized with pain that Agnatha was probably closer, both physically and emotionally, to the beautiful humanoid than he was.
Sarek, Si-s-s-s(click), Telson, Karhu, and Sirenia were all in favor of the detente, while Agnatha, Rovar, Naja, and Neko were equally opposed.
The large tank which had held Agnatha was on its side, its plastiseal panels smashed, the floor awash with the murky fluid the ambassador had lived in.
I don't want the rest of the ambassadors, or my crew, upsetand until we know precisely what happened to Agnatha, anything you have to say could damage the cause you're involved in.
Whatever Agnatha died of, he was extremely agitated at the time of his death.
But one fact was quite apparent in all the testimony there had been no discussion whatever of why Agnatha had felt such hysteria that he would have lashed out to destroy his own habitation and, in effect, his own life.
And while I have to admit that what I know about beings like Agnatha wouldn't coat the bottom of a test tube, I do know a great deal about the brain.
I would have suspected that after the death of the unfortunate Agnatha, you would have placed guards around the ambassadors' quarters.
It was Ambassador Agnatha of Jezero and Ambassador Neko from Gyuunyuu.
I am still of the opinion that the deaths of Ambassadors Agnatha and Neko were accidental, and I have the fact that all medical examinations indicate no sign whatsoever of foul play to back me up.
But should the ambassador persist in opposing the detente and be stubborn and stiff-necked, the Angel of Death would have no choice but to visit him again, and this time would take Naja with him into the great western lands, as he had taken Agnatha and Neko.
From all indications, Agnatha and Neko died from perfectly natural causesthat is, if you can call simply being dead for no reason whatever 'natural causes.
Rigel had stated was absolutely true the autopsies showed no sign of any organic disease in either Agnatha or Neko, nor any toxins or other foreign substances.
With Agnatha and Neko dead, I am now the head of the anti-Romulan delegation.