137:
6008:
1296:
6038:
874:(VLRs) that are generated through recombinatorial usage of a large panel of highly diverse leucine-rich-repeat (LRR) sequences. Three VLR genes (VLRA, VLRB, and VLRC) have been identified in lampreys and hagfish, and are expressed on three distinct lymphocytes lineages. VLRA+ cells and VLRC+ cells are T-cell-like and develop in a thymus-like lympho-epithelial structure, termed thymoids. VLRB+ cells are B-cell-like, develop in hematopoietic organs, and differentiate into "VLRB antibody"-secreting plasma cells.
6049:
2832:
911:
158:
2502:
985:
189:
6033:
6015:
3381:
6043:
736:
2081:
6027:
1460:
3248:
2060:
3022:
2902:
2853:
2678:
3325:
3043:
2767:
3001:
2881:
2364:
3276:
2129:
1112:
3220:
3091:
1983:
2522:
6021:
3930:. and prepared to admit that cyclostomes are, in fact, monophyletic. The consequence is that they may tell us little, if anything, about the dawn of vertebrate evolution, except that the intuitions of 19th century zoologists were correct in assuming that these odd vertebrates (notably, hagfishes) are strongly degenerate and have lost many characters over time.
2788:
2635:
3304:
3181:
1198:
1343:
1407:
1371:. Thus the thelodonts are generally thought to represent a polyphyletic group, although there is no firm agreement on this point; if they are monophyletic, there is no firm evidence on what their ancestral state was. "Thelodonts" were morphologically very similar, and probably closely related, to fish of the classes
1045:. Placement of this group among the jawless vertebrates is a matter of dispute. While today enough fossil diversity is known to make a close relationship among the "ostracoderms" unlikely, this has muddied the issue of the Hyperoartia's closest relatives. Traditionally the group was placed in a superclass
1948:
While the "agnatha" Conodonta was indeed jawless, if it would have continued to live, its descendants would still be closer related to e.g. humans than to lampreys, and also contempory it was closer related to the ancestor of humans. Due to such considerations, Agnatha can not be consolidated into a
726:
remain open, allowing a fungus to enter their intestines, killing them. Lampreys reproduce in freshwater riverbeds, working in pairs to build a nest and burying their eggs about an inch beneath the sediment. The resulting hatchlings go through four years of larval development before becoming adults.
601:
fluids preventing blood clotting are injected into the host, causing the host to yield more blood. Hagfish are scavengers, eating mostly dead animals. They use a row of sharp teeth to break down the animal. The fact that
Agnathan teeth are unable to move up and down limits their possible food types.
1379:, differing mainly in their covering of distinctive, small, spiny scales. These scales were easily dispersed after death; their small size and resilience makes them the most common vertebrate fossil of their time. The fish lived in both freshwater and marine environments, first appearing during the
721:
Fertilization in lampreys is external. Mode of fertilization in hagfishes is not known. Development in both groups probably is external. There is no known parental care. Not much is known about the hagfish reproductive process. It is believed that hagfish only have 30 eggs over a lifetime. There is
869:
Approximately 500 million years ago, two types of recombinatorial adaptive immune systems (AISs) arose in vertebrates. The jawed vertebrates diversify their repertoire of immunoglobulin domain-based T and B cell antigen receptors mainly through the rearrangement of V(D)J gene segments and somatic
1311:
is an extinct group of early jawless fish. The fossils show extensive shielding of the head. Many had hypocercal tails in order to generate lift to increase ease of movement through the water for their armoured bodies, which were covered in dermal bone. They also had sucking mouth parts and some
952:
to vertebrates, and living hagfish remain similar to hagfish 300 million years ago. The classification of hagfish has been controversial. The issue is whether the hagfish is itself a degenerate type of vertebrate-fish (most closely related to lampreys), or else may represent a stage which
597:, meaning they do not regulate their own body temperature. Agnathan metabolism is slow in cold water, and therefore they do not have to eat very much. They have no distinct stomach, but rather a long gut, more or less homogeneous throughout its length. Lampreys feed on other fish and mammals.
4924:
Turner S (1999). "Early
Silurian to Early Devonian thelodont assemblages and their possible ecological significance". In A. J. Boucot, J. Lawson (eds.). Palaeocommunities – Project Ecostratigraphy, Final Report (Report). International Geological Correlation Programme. Vol. 53.
1265:. Despite this, they went extinct during the lower Jurassic period, with some of the last surviving populations being in Japan. They possibly survived longer there due to the relative remoteness of the area. Originally, it was thought that they were wiped out by the
1245:, showing these animals true appearance. Their teeth make great index fossils, as many species lived and died out in a relatively short period of time. These fish reached their peak in diversity during the middle of the Ordovician, but were hit hard by the
858:, were more closely related to the gnathostomes than to the surviving agnathans, known as cyclostomes. Cyclostomes apparently split from other agnathans before the evolution of dentine and bone, which are present in many fossil agnathans, including
969:(the now-ubiquitous jawed-vertebrates). An alternative scheme proposed that jawed-vertebrates are more closely related to lampreys than to hagfish (i.e., that vertebrates include lampreys but exclude hagfish), and introduces the category
1354:
are a group of small, extinct jawless fishes with distinctive scales instead of large plates of armour. There is much debate over whether the group of
Palaeozoic fish known as the Thelodonti (formerly coelolepids) represent a
4383:
Marlétaz, Ferdinand; Timoshevskaya, Nataliya; Timoshevskiy, Vladimir A.; Parey, Elise; Simakov, Oleg; Gavriouchkina, Daria; Suzuki, Masakazu; Kubokawa, Kaoru; Brenner, Sydney; Smith, Jeramiah J.; Rokhsar, Daniel S. (2024).
1513:. The mouth opening was surrounded by small plates making the lips flexible, but without any ability to bite. Undisputed subgroups traditionally contained with Cephaloaspidomorphi, also called "Monorhina", include the
1391:. They occupied a large variety of ecological niches, with a large amount of species preferring reef ecosystems, where their flexible bodies were more at ease than the heavily armoured bulks of other jawless fish.
4663:
Bergström, S. M.; Carnes, J. B.; Ethington, R. L.; Votaw, R. B.; Wigley, P. B. (1974). "Appalachignathus, a New
Multielement Conodont Genus from the Middle Ordovician of North America".
1065:. But even though this may be correct, the lampreys represent one of the oldest divergences of the vertebrate lineage, and whether they are better united with some "ostracoderms" in the
870:
hypermutation, but none of the fundamental AIS recognition elements in jawed vertebrates have been found in jawless vertebrates. Instead, the AIS of jawless vertebrates is based on
1426:
periods. They are classically regarded as the ancestors of lampreys. Anaspids were small marine agnathans that lacked heavy bony shield and paired fins, but have a striking highly
4215:
1505:
and the anterior section of the innards. The body was in most forms well armoured as well. The head shield had a series of grooves over the whole surface forming an extensive
677:
has copious slime glands, the slime constituting their defense mechanism. The slime can sometimes clog up enemy fishes' gills, causing them to die. In direct contrast, many
1501:, and into the present day. Cephalaspidomorphi were, like most contemporary fish, very well armoured. Particularly the head shield was well developed, protecting the head,
4155:
Conodonts arose late in the Early
Cambrian and diversified into the Ordovician. ... Similar small teeth in very early Cambrian faunas ... may represent conodont ancestors.
4819:
136:
6590:
4942:
5862:
1493:, as lampreys are sometimes thought to be related to cephalaspids. If lampreys are included, they would extend the known range of the group from the early
1077:, is still to be resolved. Even the very existence of the Hyperoartia is disputed, with some analyses favoring a treatment of the "basal Hyperoartia" as a
1475:
is a broad group of extinct armored agnathans found in
Silurian and Devonian strata of North America, Europe, and China, and is named in reference to the
6845:
6840:
3562:
Märss, T.; Miller, C.G. (2004). "Thelodonts and distribution of associated conodonts from the
Llandovery-lowermost Lochkovian of the Welsh Borderland".
1949:
coherent grouping without either removing any non-cyclostomata, or by including all vertebrata thus rendering it into a junior synonym of vertebrata.
722:
very little of the larval stage that characterizes the lamprey. Lamprey are only able to reproduce once. After external fertilization, the lamprey's
6007:
6835:
6743:
1266:
4585:
Gabbott, S.E.; R. J. Aldridge; J. N. Theron (1995). "A giant conodont with preserved muscle tissue from the Upper
Ordovician of South Africa".
5125:
5100:
5069:
5042:
4865:
4450:
6595:
3812:
Oisi Y, Ota KG, Kuraku S, Fujimoto S, Kuratani S (January 2013). "Craniofacial development of hagfishes and the evolution of vertebrates".
5301:
3985:
Stock, D.W.; Whitt, G.S. (August 1992). "Evidence from 18S ribosomal RNA sequences that lampreys and hagfishes form a natural group".
3942:
Stock, D.W.; Whitt, G.S. (August 1992). "Evidence from 18S ribosomal RNA sequences that lampreys and hagfishes form a natural group".
4288:
4132:
4122:
3596:
585:
hypothesis was accepted (and is still sometimes used as a strictly morphological descriptor) to reference hagfish plus vertebrates.
5227:"Hagfish from the Cretaceous Tethys Sea and a reconciliation of the morphological–molecular conflict in early vertebrate phylogeny"
5174:
Delsuc F, Philippe H, Tsagkogeorga G, Simion P, Tilak MK, Turon X, López-Legentil S, Piette J, Lemaire P, Douzery EJ (April 2018).
4817:
Turner S, Tarling DH (1982). "Thelodont and other agnathan distributions as tests of Lower
Paleozoic continental reconstructions".
6037:
5225:
Miyashita, Tetsuto; Coates, Michael I.; Farrar, Robert; Larson, Peter; Manning, Phillip L.; Wogelius, Roy A.; et al. (2019).
6792:
5855:
1246:
822:
Many
Ordovician, Silurian, and Devonian agnathans were armored with heavy bony-spiky plates. The first armored agnathans—the
6748:
3671:"microRNAs reveal the interrelationships of hagfish, lampreys, and gnathostomes and the nature of the ancestral vertebrate"
940:. The group has gone through the most extensive gene loss of all vertebrates, with 1,386 missing gene families. Along with
6600:
5142:
3725:
Mallatt, J.; Sullivan, J. (December 1998). "28S and 18S rDNA sequences support the monophyly of lampreys and hagfishes".
6825:
6607:
4318:
Wu, Fenfang; Chen, Liyong; Ren, Yong; Yang, Xiaojing; Yu, Tongzhou; Feng, Bo; Chen, Shangwu; Xu, Anlong (October 2016).
871:
3926:
Although I was among the early supporters of vertebrate paraphyly, I am impressed by the evidence provided by Heimberg
6704:
1295:
3669:
Heimberg, Alysha M.; Cowper-Sal·lari, Richard; Sémon, Marie; Donoghue, Philip C.J.; Peterson, Kevin J. (2010-11-09).
581:, because they secondarily lost vertebrae; before this event was inferred from molecular and developmental data, the
6048:
3765:
Delarbre C, Gallut C, Barriel V, Janvier P, Gachelin G (February 2002). "Complete mitochondrial DNA of the hagfish,
459:
6735:
5887:
5848:
4926:
4628:
Quinton, Page C. (2016). "Effects of extraction protocols on the oxygen isotope composition of conodont elements".
1169:
646:. Fertilization and development are both external. There is no parental care in the Agnatha class. The Agnatha are
6042:
6575:
4950:
3505:
188:
6585:
1435:
1384:
812:
807:, a class of agnathans which arose in the early Cambrian, remained common enough until their extinction in the
789:. They have been tentatively assigned to Agnatha by Janvier. A third possible agnathid from the same region is
4684:
4195:
795:. A possible agnathid that has not been formally described was reported by Simonetti from the Middle Cambrian
6032:
6014:
4168:
4030:"Identification of vertebra-like elements and their possible differentiation from sclerotomes in the hagfish"
3135:
6633:
6026:
6657:
5294:
435:
4716:"Global climate changes account for the main trends of conodont diversity but not for their final demise"
4715:
3105:
2284:
6769:
4268:
3119:
2746:
949:
3769:: The comparative analysis of mitochondrial DNA sequences strongly supports the cyclostome monophyly".
2831:
2783:
2694:
2673:
6717:
6628:
6580:
6267:
5238:
4985:
4828:
4730:
4672:
4637:
4594:
4484:
4397:
4331:
4183:
4150:
4041:
3994:
3951:
3889:
3821:
3778:
3623:
3571:
3520:
2827:
1368:
4857:
Vertebrate fossils and the evolution of scientific concepts: Writings in tribute to Beverly Halstead
6830:
6797:
3017:
245:
165:
2804:
2300:
6316:
6164:
4906:
4748:
4696:
4688:
4610:
4500:
4454:
4207:
3855:
3544:
3086:
2648:
1876:
1472:
1447:
1133:
1066:
1014:
770:
183:
2607:
2501:
1427:
910:
6774:
5034:
Major events in early vertebrate evolution: Palaeontology, phylogeny, genetics, and development
4768:"Lower Jurassic conodonts from the Inuyama area of Japan: implications for conodont extinction"
1367:". This defining character is not necessarily a result of shared ancestry, as it may have been
984:
846:
the agnathans had reached the high point of their evolution. Most of the ostracoderms, such as
6756:
6490:
6438:
6395:
6389:
6352:
6340:
6310:
5965:
5871:
5287:
5266:
5207:
5121:
5096:
5090:
5065:
5059:
5038:
5032:
5013:
4898:
4861:
4855:
4799:
4431:
4413:
4365:
4347:
4294:
4284:
4249:
4199:
4128:
4067:
4010:
3967:
3917:
3847:
3794:
3742:
3702:
3651:
3536:
3380:
2876:
1978:
1234:
1125:
1101:
1054:
748:
6761:
6820:
6784:
6623:
6534:
6517:
6231:
6146:
5256:
5246:
5197:
5187:
5003:
4993:
4890:
4836:
4789:
4779:
4738:
4680:
4645:
4602:
4558:
4527:
4492:
4421:
4405:
4355:
4339:
4276:
4241:
4232:
Baker CV (December 2008). "The evolution and elaboration of vertebrate neural crest cells".
4191:
4057:
4049:
4002:
3959:
3907:
3897:
3837:
3829:
3786:
3734:
3692:
3682:
3641:
3631:
3579:
3528:
3038:
2996:
2897:
2762:
2569:
1651:
1431:
1364:
1308:
1285:
1269:
at the end of the Triassic. Instead, it is now thought that they were out competed by newer
1094:
1070:
937:
800:
682:
381:
323:
286:
175:
51:
6020:
4881:
Donoghue PC, Forey PL, Aldridge RJ (May 2000). "Conodont affinity and chordate phylogeny".
735:
6503:
6466:
6346:
6297:
6118:
5920:
5703:
5457:
5423:
5350:
4563:
3738:
3299:
2227:
2080:
1514:
1465:
1035:
1019:
973:
to group vertebrates near hagfish. Recent DNA evidence has supported the original scheme.
754:
670:
309:
1509:
organ. The eyes were rather small and placed on the top of the head. There was no proper
5242:
4989:
4832:
4734:
4676:
4641:
4598:
4488:
4426:
4401:
4385:
4335:
4187:
4045:
3998:
3955:
3893:
3825:
3782:
3627:
3575:
3524:
3247:
2059:
1459:
6730:
6478:
6456:
6401:
6383:
6334:
6326:
6303:
6261:
6237:
5982:
5572:
5544:
5451:
5261:
5226:
5202:
5175:
5008:
4973:
4894:
4360:
4319:
4280:
4062:
4029:
3912:
3877:
3697:
3670:
3646:
3609:
3608:
Ruggiero, Michael; Gordon, Dennis P.; Orrell, Thomas M.; Bailly, Nicolas (April 2015).
3243:
3215:
3021:
2848:
2336:
2322:
2250:
2124:
2076:
2010:
1685:
1671:
1262:
1163:
1136:
1082:
945:
785:
740:
262:
2901:
442:
6814:
6695:
6427:
6274:
6249:
6198:
6111:
5993:
5973:
5815:
5720:
5583:
5527:
4840:
4752:
4546:
3583:
3548:
3474:
3376:
2387:
2359:
1840:
1254:
1222:
1157:
1117:
1086:
796:
779:
710:
598:
556:
473:
364:
343:
294:
93:
4910:
4743:
4700:
4504:
4211:
2852:
2677:
6539:
6418:
6358:
6243:
6176:
6071:
5695:
5650:
5555:
5499:
5336:
5118:
Evolution of the Vertebrates : A history of the backboned animals through time
5086:
4614:
4084:
3859:
3485:
3324:
3176:
3042:
2766:
2732:
2719:
2484:
2403:
1802:
1562:
1525:
1506:
1372:
1315:
1278:
1078:
1046:
1027:
966:
958:
899:
851:
816:
706:
702:
694:
669:
In modern agnathans, the body is covered in skin, with neither dermal or epidermal
631:
627:
518:
498:
317:
4649:
4101:
3000:
2880:
2363:
1956:. (2019) is considered compatible with both morphological and molecular evidence.
4998:
4766:
Du, Yixing; Onoue, Tetsuji; Tomimatsu, Yuki; Wu, Qiangwang; Rigo, Manuel (2023).
4453:. U.C. Museum of Paleontology. University of California, Berkeley. Archived from
3842:
3636:
3504:
Yang, Chuan; Li, Xian-Hua; Zhu, Maoyan; Condon, Daniel J.; Chen, Junyuan (2018).
6689:
6526:
6512:
6448:
6377:
6182:
6137:
6084:
5929:
5612:
5512:
3275:
3201:
2630:
2263:
2128:
2108:
2055:
1825:
1701:
1595:
1575:
1517:
1481:
1476:
1360:
1323:
1042:
1031:
1008:
995:
978:
962:
823:
647:
594:
526:
510:
335:
302:
68:
6709:
5231:
Proceedings of the National Academy of Sciences of the United States of America
4475:
Shu, Degan (April 2003). "A paleontological perspective of vertebrate origin".
4409:
3882:
Proceedings of the National Academy of Sciences of the United States of America
3219:
3090:
1982:
1221:
period. They were very diverse in terms of lifestyles, with some species being
1111:
6544:
6443:
6288:
6225:
6170:
6152:
5951:
5942:
5808:
5747:
5600:
5485:
5439:
5373:
5192:
4784:
4767:
4245:
3878:"MicroRNAs revive old views about jawless vertebrate divergence and evolution"
3479:
3320:
3072:
2982:
2659:
2521:
1963:
1779:
1749:
1551:
1539:
1521:
1380:
1348:
1332:
1319:
1283:
1237:". It wasn't until the mid-1980s that body fossils of conodonts were found in
1203:
1183:
1099:
1062:
839:
791:
766:
698:
643:
578:
560:
544:
532:
494:
476:
354:
280:
273:
230:
157:
149:
113:
78:
6680:
5176:"A phylogenomic framework and timescale for comparative studies of tunicates"
4803:
4417:
4351:
4203:
3540:
547:
data, strongly supports the hypothesis that both groups of living agnathans,
6498:
6255:
6219:
6210:
6124:
5739:
5429:
5403:
5330:
5251:
4006:
3963:
3902:
3687:
3271:
2182:
1628:
1356:
1301:
1242:
1230:
1152:
954:
855:
847:
831:
827:
758:
651:
619:
575:
491:
329:
268:
200:
170:
118:
62:
5270:
5211:
5017:
4902:
4435:
4369:
4298:
4267:
Hirano, Masayuki; Das, Sabyasachi; Guo, Peng; Cooper, Max D. (2011-01-01).
4253:
4071:
3921:
3851:
3798:
3790:
3706:
3655:
3506:"Geochronological constraint on the Cambrian Chengjiang biota, South China"
2787:
2634:
1418:
is an extinct group of primitive jawless vertebrates that lived during the
1006:
relatives. Examples of hyperoartians from early in their fossil record are
5279:
4014:
3971:
3746:
3303:
3180:
1053:(hagfishes). More recently, it has been proposed that the Myxini are more
6674:
6461:
6406:
6363:
6158:
5957:
5935:
5897:
5709:
5637:
5625:
5387:
5358:
5311:
4794:
4531:
3614:
3459:
2517:
2094:
1939:
1717:
1498:
1494:
1423:
1419:
1412:
1396:
1388:
1376:
1270:
1250:
1238:
1218:
1214:
1210:
1186:
1178:
1144:
1129:
1074:
1058:
1041:, but this is increasingly considered an artificial arrangement based on
1038:
1023:
970:
941:
863:
859:
843:
808:
804:
762:
654:
611:
582:
567:
506:
502:
487:
220:
108:
103:
88:
83:
73:
55:
31:
3833:
3532:
681:
sported extensive exoskeletons composed of either massive, heavy dermal
6549:
6089:
6079:
5822:
5661:
5507:
4692:
4496:
4053:
2497:
1490:
1439:
1342:
1258:
1226:
1197:
999:
989:
915:
811:
that their teeth (the only parts of them that were usually fossilized)
674:
639:
571:
552:
548:
145:
123:
98:
17:
4343:
5912:
5728:
5685:
5674:
5324:
4606:
3720:
3718:
3716:
3482:, an alternate name for the above parallel, or sister, classification
1579:
1442:, became extinct due to the environmental upheaval during that time.
1069:, or not closer to these than to e.g. to other "ostracoderms" of the
1050:
1003:
921:
904:
723:
635:
514:
484:
465:
448:
210:
35:
6651:
5840:
1489:
as extinct, but the name is sometimes used in the classification of
1406:
638:). All living and most extinct Agnatha do not have an identifiable
6368:
1486:
1140:
933:
835:
774:
734:
658:
540:
6722:
697:, have no paired appendages, although most do have a dorsal or a
5882:
5753:
5651:
Lissamphibia (modern amphibians: frogs, salamanders, caecilians)
1502:
1148:
623:
536:
6655:
5844:
5283:
4269:"Chapter 4 – The Evolution of Adaptive Immunity in Vertebrates"
1544:
Phylogeny based on the work of Mikko Haaramo and Delsuc et al.
957:). The original scheme groups hagfish and lampreys together as
5061:
Molecules and Morphology in Evolution: Conflict or compromise?
1510:
1229:, these animals were only known because of their microscopic,
925:
615:
522:
1359:, or disparate stem groups to the major lines of jawless and
1128:
were a primitive order of agnathans that were endemic to the
961:(or historically, Agnatha), as the oldest surviving clade of
757:, agnathans were prominent among the early fish in the early
5545:
Chondrichthyes (cartilaginous fish: sharks, rays, chimaeras)
998:
is a disputed group of vertebrates that includes the modern
928:-shaped slime-producing marine animals (occasionally called
423:
399:
1249:
event. They then reached another spike in diversity in the
426:
420:
402:
396:
5064:. Cambridge, UK: Cambridge University Press. p. 142.
614:, modern agnathans are characterised by absence of paired
5095:. Chicago, IL: University of Chicago Press. p. 131.
4883:
Biological Reviews of the Cambridge Philosophical Society
4685:
10.1666/0022-3360(2001)075<1174:CPPF>2.0.CO;2
4196:
10.1666/0022-3360(2001)075<1174:CPPF>2.0.CO;2
769:
musculature, and gills are known from the early Cambrian
411:
408:
390:
387:
4320:"An inhibitory receptor of VLRB in the agnathan lamprey"
3610:"A Higher Level Classification of All Living Organisms"
3760:
3758:
3756:
953:
precedes the evolution of the vertebral column (as do
932:). They are the only known living animals that have a
5037:. Washington, DC: Taylor & Francis. p. 188.
4386:"The hagfish genome and the evolution of vertebrates"
739:
Evolution of jawless fishes. The diagram is based on
417:
393:
6531:
6486:
6453:
6435:
6285:
6207:
6134:
6101:
5989:
5978:
5969:
5962:
5947:
5925:
5908:
4545:
Sweet, Walter C.; Cooper, Barry J. (December 2008).
4028:
Ota KG, Fujimoto S, Oisi Y, Kuratani S (June 2011).
622:
both in larvae and adults; and seven or more paired
6664:
6616:
6568:
6477:
6426:
6417:
6325:
6284:
6206:
6197:
6133:
6100:
6070:
6060:
5896:
5738:
5719:
5694:
5683:
5659:
5635:
5610:
5581:
5553:
5525:
5498:
5483:
5438:
5412:
5386:
5371:
5349:
4714:Ginot, Samuel; Goudemand, Nicolas (December 2020).
4275:. Vol. 109. Academic Press. pp. 125–157.
709:, did have paired fins, a trait inherited in their
472: 'jaws') is a paraphyletic infraphylum of non-
414:
384:
353:
253:
182:
45:
4127:, Blackwell, 3rd edition, Figure 3.25 on page 73,
1143:. These creatures are the earliest known group of
4820:Palaeogeography, Palaeoclimatology, Palaeoecology
555:, are more closely related to each other than to
1155:). Currently the group includes 3 known genera,
1085:that may in fact be very close to the ancestral
574:in total. Hagfish are considered members of the
4547:"C.H. Pander's introduction to conodonts, 1856"
3675:Proceedings of the National Academy of Sciences
1261:, but dramatically increased in numbers in the
570:. Living jawless fish comprise about 120
5856:
5295:
4234:Current Opinion in Genetics & Development
8:
5116:Colbert, Michael; Morales, Edwin H. (1991).
4145:Stanley, Steven M.; Luczaj, John A. (2015).
1225:and others being macropredators. For over a
1213:were eel like agnathans that lived from the
566:The oldest fossil agnathans appeared in the
1061:, while the Hyperoartia are retained among
6652:
6423:
6203:
6067:
5863:
5849:
5841:
5735:
5691:
5667:
5643:
5618:
5593:
5565:
5537:
5495:
5491:
5444:
5416:
5396:
5383:
5379:
5346:
5302:
5288:
5280:
5120:(4th ed.). New York, NY: Wiley-Liss.
3871:
3869:
1363:. Thelodonts are united in possession of "
753:Although a minor element of modern marine
156:
135:
42:
5260:
5250:
5201:
5191:
5007:
4997:
4793:
4783:
4742:
4562:
4425:
4359:
4167:Sweet, W. C.; Donoghue, P. C. J. (2001).
4061:
3911:
3901:
3841:
3696:
3686:
3645:
3635:
1369:evolved independently by different groups
626:pouches. Lampreys have a light sensitive
357:included but traditionally excluded taxa
881:
819:from the late Cambrian to the Triassic.
5430:Thaliacea (pyrosomes, salps, doliolids)
3496:
1312:species may have lived in fresh water.
5147:– lancets, tunicates, and vertebrates"
4974:"Squamation and ecology of thelodonts"
5169:
5167:
4169:"Conodonts: past, present and future"
3771:Molecular Phylogenetics and Evolution
3739:10.1093/oxfordjournals.molbev.a025897
7:
4941:Kazlev MA, White T (March 6, 2001).
1034:" (jawless armored "fishes") of the
693:Almost all agnathans, including all
4520:Family-group names of fossil fishes
3291:
3263:
3235:
3207:
3196:
3168:
3111:
3078:
3067:
2988:
2977:
2868:
2819:
2738:
2665:
2654:
2622:
2599:
2564:
2490:
2379:
2351:
2328:
2276:
2269:
2242:
2219:
2212:
2177:
2100:
2047:
2040:
2005:
1998:
1970:
1959:
1817:
1794:
1771:
1764:
1741:
1677:
1667:
1643:
1620:
1568:
1558:
1547:
1385:Frasnian–Famennian extinction event
1257:. They were relatively rare in the
1030:still place these forms among the "
4895:10.1111/j.1469-185X.1999.tb00045.x
4772:Frontiers in Ecology and Evolution
4281:10.1016/b978-0-12-387664-5.00004-2
25:
6846:Taxa named by Edward Drinker Cope
6841:Extant Cambrian first appearances
4854:Sarjeant WA, Halstead LB (1995).
4091:(6th ed.) Saunders, Philadelphia.
3597:Shorter Oxford English Dictionary
3513:Journal of the Geological Society
1952:The new phylogeny from Miyashita
1430:tail. They first appeared in the
1314:The taxon contains the subgroups
701:. Some fossil agnathans, such as
6047:
6041:
6036:
6031:
6025:
6019:
6013:
6006:
5573:Actinopterygii (ray-finned fish)
4939:The early and mid Silurian. See
4221:from the original on 2022-10-30.
3584:10.1111/j.0031-0239.2004.00409.x
3379:
3323:
3302:
3274:
3246:
3218:
3179:
3089:
3041:
3020:
2999:
2900:
2879:
2851:
2830:
2786:
2765:
2676:
2633:
2520:
2500:
2362:
2127:
2079:
2058:
1981:
1458:
1405:
1341:
1294:
1196:
1110:
983:
909:
380:
187:
4744:10.1016/j.gloplacha.2020.103325
4564:10.18814/epiiugs/2008/v31i4/009
4518:van der Laan, Richard (2016). "
3727:Molecular Biology and Evolution
1438:, where most species, save for
765:animal apparently having fins,
6836:Terreneuvian first appearances
4271:. In Alt, Frederick W. (ed.).
4087:. & Parsons, T.S. (1985):
1485:. Most biologists regard this
1253:before again declining in the
1247:Ordovician-Silurian extinction
1217:up until the beginning of the
944:, hagfish are jawless and are
678:
610:In addition to the absence of
513:, among others). Among recent
148:, a jawless fish belonging to
1:
4972:Ferrón HG, Botella H (2017).
4650:10.1016/j.chemgeo.2016.03.023
3876:Janvier, P. (November 2010).
872:variable lymphocyte receptors
685:or small mineralized scales.
497:, consisting of both living (
6608:List of transitional fossils
4999:10.1371/journal.pone.0172781
4841:10.1016/0031-0182(82)90027-X
4524:European Journal of Taxonomy
4451:"Introduction to the Myxini"
3637:10.1371/journal.pone.0119248
862:. Agnathans declined in the
838:)—are known from the middle
455: 'without' and
5404:Appendicularia (larvaceans)
4723:Global and Planetary Change
1540:Placodermi § Cladogram
1434:, and flourished until the
1383:, and perishing during the
1147:(chordates with a skull of
1073:, or even the long-extinct
1022:that lived during the Late
168:of extinct agnathan genus,
27:Infraphylum of jawless fish
6862:
5888:Timeline of fish evolution
5831:denote paraphyletic groups
5710:Squamata (scaled reptiles)
4927:Cambridge University Press
4410:10.1038/s41586-024-07070-3
1537:
883:Subgroups of jawless fish
746:
458:
441:
29:
6642:
6576:Lists of prehistoric fish
6004:
5878:
5802:
5748:Crocodilia (crocodilians)
5704:Rhynchocephalia (tuatara)
5670:
5646:
5621:
5596:
5568:
5540:
5494:
5447:
5419:
5399:
5382:
5345:
5319:
5193:10.1186/s12915-018-0499-2
5151:Mikko's Phylogeny Archive
5058:Patterson, Colin (1987).
4785:10.3389/fevo.2023.1135789
4246:10.1016/j.gde.2008.11.006
3449:
3374:
3317:
3296:
3289:
3268:
3261:
3240:
3233:
3212:
3205:
3194:
3173:
3166:
3132:
3116:
3109:
3083:
3076:
3065:
3035:
3014:
2993:
2986:
2975:
2894:
2873:
2866:
2845:
2824:
2817:
2801:
2780:
2759:
2743:
2736:
2716:
2691:
2670:
2663:
2652:
2627:
2620:
2604:
2573:
2562:
2515:
2495:
2488:
2400:
2384:
2377:
2356:
2349:
2333:
2326:
2297:
2281:
2274:
2267:
2247:
2240:
2224:
2217:
2186:
2175:
2121:
2105:
2098:
2073:
2052:
2045:
2014:
2003:
1996:
1975:
1968:
1873:
1838:
1822:
1815:
1799:
1792:
1776:
1769:
1762:
1746:
1739:
1714:
1698:
1682:
1675:
1665:
1648:
1641:
1625:
1618:
1593:
1573:
1566:
1556:
1277:
1233:tooth structures called "
1018:, fish-like animals with
898:
887:
361:
258:
184:Scientific classification
164:
155:
143:
134:
5809:Ascidiacea (sea squirts)
5601:Actinistia (coelacanths)
4477:Chinese Science Bulletin
4449:Speer, Brian R. (1997).
4153:Education. p. 311.
4124:Vertebrate Palaeontology
1843:(vertebrates with jaws)
1436:Late Devonian extinction
1177:
1093:
521:to all vertebrates with
30:Not to be confused with
6634:Vertebrate paleontology
5359:Leptocardii (lancelets)
5252:10.1073/pnas.1814794116
5141:Haaramo, Mikko (2007).
4665:Journal of Paleontology
4176:Journal of Paleontology
4007:10.1126/science.1496398
3964:10.1126/science.1496398
3903:10.1073/pnas.1014583107
3688:10.1073/pnas.1010350107
3136:Polybranchiaspidiformes
1059:skull-bearing chordates
5513:Hyperoartia (lampreys)
4273:Advances in Immunology
4104:. Aquaticcommunity.com
3791:10.1006/mpev.2001.1045
744:
276:(hagfish and lampreys)
6770:Paleobiology Database
4860:. Gordon and Breach.
4121:Benton, M. J. (2005)
4034:Nature Communications
3843:20.500.14094/D1005717
1357:monophyletic grouping
866:and never recovered.
761:. Two types of Early
738:
661:contains 2 chambers.
6629:Transitional fossils
6268:Pseudopetalichthyida
5729:Testudines (turtles)
4532:10.5852/ejt.2018.466
4147:Earth System History
4089:The Vertebrate Body.
2828:Traquairaspidiformes
826:, precursors to the
618:; the presence of a
559:, forming the clade
6826:Paraphyletic groups
5823:Reptilia (reptiles)
5531:(jawed vertebrates)
5243:2019PNAS..116.2146M
5085:Hall, Brian Keith;
5031:Ahlberg PE (2001).
4990:2017PLoSO..1272781F
4833:1982PPP....39..295T
4735:2020GPC...19503325G
4677:2001JPal...75.1174S
4642:2016ChGeo.431...36Q
4599:1995Natur.374..800G
4489:2003ChSBu..48..725S
4402:2024Natur.627..811M
4336:2016NatSR...633760W
4188:2001JPal...75.1174S
4046:2011NatCo...2..373O
3999:1992Sci...257..787S
3956:1992Sci...257..787S
3894:2010PNAS..10719137J
3888:(45): 19137–19138.
3834:10.1038/nature11794
3826:2013Natur.493..175O
3783:2002MolPE..22..184D
3681:(45): 19379–19383.
3628:2015PLoSO..1019248R
3576:2004Palgy..47.1211M
3533:10.1144/jgs2017-103
3525:2018JGSoc.175..659Y
3106:Polybranchiaspidida
3018:Archipelepidiformes
2285:Protopanderodontida
1497:period through the
884:
630:(homologous to the
367:(jawed vertebrates)
166:Life reconstruction
6317:Ischnacanthiformes
6165:Cephalaspidomorphi
5675:Mammalia (mammals)
5587:(lobe-finned fish)
5559:(bony vertebrates)
4497:10.1007/BF03187041
4324:Scientific Reports
4054:10.1038/ncomms1355
3767:Eptatretus burgeri
3120:Huananaspidiformes
3087:Eugaleaspidiformes
2747:Tesseraspidiformes
2649:Heterostracomorphi
1877:Cephalaspidomorpha
1596:Petromyzontomorpha
1473:Cephalaspidomorphi
1134:Maotianshan Shales
1067:Cephalaspidomorphi
1049:together with the
882:
842:, and by the Late
771:Maotianshan shales
745:
517:, cyclostomes are
6808:
6807:
6757:Open Tree of Life
6658:Taxon identifiers
6649:
6648:
6564:
6563:
6560:
6559:
6491:Palaeonisciformes
6439:Onychodontiformes
6396:Petalodontiformes
6390:Iniopterygiformes
6353:Phoebodontiformes
6341:Ctenacanthiformes
6311:Diplacanthiformes
6193:
6192:
5966:Myllokunmingiidae
5872:Evolution of fish
5838:
5837:
5820:³orders of class
5806:¹orders of class
5798:
5797:
5794:
5793:
5790:
5789:
5786:
5785:
5782:
5781:
5778:
5777:
5774:
5773:
5770:
5769:
5766:
5765:
5762:
5761:
5626:Dipnoi (lungfish)
5521:
5520:
5479:
5478:
5475:
5474:
5471:
5470:
5467:
5466:
5367:
5366:
5127:978-0-471-85074-8
5102:978-0-226-31568-3
5071:978-0-521-32271-3
5044:978-0-415-23370-5
4929:. pp. 42–78.
4867:978-2-88124-996-9
4593:(6525): 800–803.
4396:(8005): 811–820.
4344:10.1038/srep33760
3950:(5071): 787–789.
3733:(12): 1706–1718.
3465:
3464:
3446:
3445:
3437:
3436:
3428:
3427:
3419:
3418:
3410:
3409:
3401:
3400:
3392:
3391:
3363:
3362:
3354:
3353:
3345:
3344:
3336:
3335:
3155:
3154:
3146:
3145:
3054:
3053:
2965:
2964:
2958:
2957:
2949:
2948:
2940:
2939:
2931:
2930:
2922:
2921:
2913:
2912:
2877:Cyathaspidiformes
2784:Lepidaspidiformes
2705:
2704:
2551:
2550:
2542:
2541:
2533:
2532:
2475:
2474:
2468:
2467:
2459:
2458:
2450:
2449:
2441:
2440:
2432:
2431:
2423:
2422:
2414:
2413:
2311:
2310:
2165:
2164:
2158:
2157:
2149:
2148:
2140:
2139:
1979:Myllokunmingiidae
1945:
1944:
1933:
1932:
1924:
1923:
1915:
1914:
1906:
1905:
1897:
1896:
1888:
1887:
1870:
1869:
1861:
1860:
1852:
1851:
1728:
1727:
1607:
1606:
1531:
1530:
1455:
1402:
1338:
1291:
1251:mid-late Devonian
1235:Conodont elements
1192:
1107:
1102:Myllokunmingiidae
1087:jawed vertebrates
830:and hence to the
749:Evolution of fish
711:jawed descendants
679:extinct agnathans
373:
372:
249:
129:
16:(Redirected from
6853:
6801:
6800:
6788:
6787:
6778:
6777:
6765:
6764:
6752:
6751:
6739:
6738:
6726:
6725:
6713:
6712:
6700:
6699:
6698:
6685:
6684:
6683:
6653:
6624:Prehistoric life
6535:Pycnodontiformes
6533:
6518:Acipenseriformes
6488:
6455:
6437:
6424:
6287:
6232:Brindabellaspida
6209:
6204:
6147:Pteraspidomorphi
6136:
6103:
6068:
6052:
6051:
6045:
6040:
6035:
6030:
6029:
6023:
6018:
6017:
6010:
5991:
5980:
5971:
5964:
5949:
5927:
5910:
5865:
5858:
5851:
5842:
5736:
5692:
5688:
5668:
5664:
5644:
5640:
5619:
5615:
5594:
5590:
5588:
5566:
5562:
5560:
5538:
5534:
5532:
5508:Myxini (hagfish)
5496:
5492:
5488:
5445:
5417:
5397:
5392:
5384:
5380:
5376:
5347:
5304:
5297:
5290:
5281:
5275:
5274:
5264:
5254:
5237:(6): 2146–2151.
5222:
5216:
5215:
5205:
5195:
5171:
5162:
5161:
5159:
5157:
5138:
5132:
5131:
5113:
5107:
5106:
5082:
5076:
5075:
5055:
5049:
5048:
5028:
5022:
5021:
5011:
5001:
4969:
4963:
4962:
4960:
4958:
4949:. Archived from
4937:
4931:
4930:
4921:
4915:
4914:
4878:
4872:
4871:
4851:
4845:
4844:
4827:(3–4): 295–311.
4814:
4808:
4807:
4797:
4787:
4763:
4757:
4756:
4746:
4720:
4711:
4705:
4704:
4660:
4654:
4653:
4630:Chemical Geology
4625:
4619:
4618:
4607:10.1038/374800a0
4582:
4576:
4575:
4573:
4571:
4566:
4542:
4536:
4535:
4515:
4509:
4508:
4472:
4466:
4465:
4463:
4462:
4446:
4440:
4439:
4429:
4380:
4374:
4373:
4363:
4315:
4309:
4308:
4306:
4305:
4264:
4258:
4257:
4229:
4223:
4222:
4220:
4182:(6): 1174–1184.
4173:
4164:
4158:
4157:
4149:(4th ed.).
4142:
4136:
4119:
4113:
4112:
4110:
4109:
4098:
4092:
4082:
4076:
4075:
4065:
4025:
4019:
4018:
3982:
3976:
3975:
3939:
3933:
3932:
3915:
3905:
3873:
3864:
3863:
3845:
3820:(7431): 175–80.
3809:
3803:
3802:
3762:
3751:
3750:
3722:
3711:
3710:
3700:
3690:
3666:
3660:
3659:
3649:
3639:
3605:
3599:
3594:
3588:
3587:
3570:(5): 1211–1265.
3559:
3553:
3552:
3510:
3501:
3383:
3327:
3306:
3292:
3278:
3264:
3250:
3236:
3222:
3208:
3197:
3183:
3169:
3112:
3093:
3079:
3068:
3045:
3039:Furcacaudiformes
3024:
3003:
2997:Thelodontiformes
2989:
2978:
2904:
2898:Pteraspidiformes
2883:
2869:
2855:
2834:
2820:
2790:
2769:
2763:Cardipeltiformes
2739:
2695:Tesakoviaspidida
2680:
2674:Astraspidiformes
2666:
2655:
2637:
2623:
2600:
2591:
2575:
2574:
2570:Pteraspidomorphi
2565:
2524:
2504:
2491:
2380:
2366:
2352:
2329:
2277:
2270:
2243:
2220:
2213:
2204:
2188:
2187:
2178:
2131:
2101:
2083:
2062:
2048:
2041:
2032:
2016:
2015:
2006:
1999:
1985:
1971:
1960:
1818:
1795:
1772:
1765:
1742:
1678:
1668:
1652:Pteraspidomorpha
1644:
1621:
1569:
1559:
1548:
1462:
1453:
1416:(without shield)
1409:
1400:
1365:thelodont scales
1345:
1336:
1309:Pteraspidomorphi
1298:
1289:
1286:Pteraspidomorphi
1267:large extinction
1200:
1190:
1170:Zhongjianichthys
1126:myllokunmingiids
1114:
1105:
1095:Myllokunmingiida
1071:Pteraspidomorphi
1043:ancestral traits
1020:hypocercal tails
987:
938:vertebral column
913:
885:
801:British Columbia
695:extant agnathans
650:or cold, with a
469:
462:
452:
445:
433:
432:
429:
428:
425:
422:
419:
416:
413:
410:
405:
404:
401:
398:
395:
392:
389:
386:
330:Thelodontomorphi
324:Pteraspidomorphi
287:Myllokunmingiida
254:Groups included
244:
192:
191:
176:Pteraspidomorphi
160:
139:
128:
65:
52:Cambrian Stage 3
49:Temporal range:
48:
43:
21:
6861:
6860:
6856:
6855:
6854:
6852:
6851:
6850:
6811:
6810:
6809:
6804:
6796:
6791:
6783:
6781:
6773:
6768:
6760:
6755:
6747:
6742:
6734:
6729:
6721:
6716:
6708:
6703:
6694:
6693:
6688:
6679:
6678:
6673:
6660:
6650:
6645:
6638:
6612:
6556:
6504:Polypteriformes
6473:
6467:Tetrapodomorpha
6413:
6347:Hybodontiformes
6321:
6298:Acanthodiformes
6280:
6189:
6129:
6119:Paraconodontida
6096:
6064:
6056:
6055:
6054:
6046:
6024:
6012:
6002:
5921:Cephalochordate
5892:
5874:
5869:
5839:
5834:
5814:²subclasses of
5758:
5734:
5715:
5684:
5679:
5660:
5655:
5636:
5631:
5611:
5606:
5586:
5585:
5582:
5577:
5558:
5557:
5554:
5549:
5530:
5529:
5526:
5517:
5484:
5463:
5458:Aplousobranchia
5434:
5424:Stolidobranchia
5408:
5390:
5389:
5372:
5363:
5351:Cephalochordata
5341:
5315:
5308:
5278:
5224:
5223:
5219:
5173:
5172:
5165:
5155:
5153:
5140:
5139:
5135:
5128:
5115:
5114:
5110:
5103:
5084:
5083:
5079:
5072:
5057:
5056:
5052:
5045:
5030:
5029:
5025:
4984:(2): e0172781.
4971:
4970:
4966:
4956:
4954:
4940:
4938:
4934:
4923:
4922:
4918:
4880:
4879:
4875:
4868:
4853:
4852:
4848:
4816:
4815:
4811:
4765:
4764:
4760:
4718:
4713:
4712:
4708:
4662:
4661:
4657:
4627:
4626:
4622:
4584:
4583:
4579:
4569:
4567:
4544:
4543:
4539:
4517:
4516:
4512:
4474:
4473:
4469:
4460:
4458:
4448:
4447:
4443:
4382:
4381:
4377:
4317:
4316:
4312:
4303:
4301:
4291:
4266:
4265:
4261:
4231:
4230:
4226:
4218:
4171:
4166:
4165:
4161:
4144:
4143:
4139:
4120:
4116:
4107:
4105:
4100:
4099:
4095:
4083:
4079:
4027:
4026:
4022:
3993:(5071): 787–9.
3984:
3983:
3979:
3941:
3940:
3936:
3875:
3874:
3867:
3811:
3810:
3806:
3764:
3763:
3754:
3724:
3723:
3714:
3668:
3667:
3663:
3622:(4): e0119248.
3607:
3606:
3602:
3595:
3591:
3561:
3560:
3556:
3508:
3503:
3502:
3498:
3494:
3471:
3466:
3454:
3453:
3447:
3438:
3429:
3420:
3411:
3402:
3393:
3364:
3355:
3346:
3337:
3300:Benneviaspidida
3156:
3147:
3055:
2961:
2960:
2959:
2950:
2941:
2932:
2923:
2914:
2706:
2593:
2592:
2589:
2584:
2583:
2582:
2552:
2543:
2534:
2471:
2470:
2469:
2460:
2451:
2442:
2433:
2424:
2415:
2312:
2228:Paraconodontida
2206:
2205:
2202:
2197:
2196:
2195:
2161:
2160:
2159:
2150:
2141:
2034:
2033:
2030:
2025:
2024:
2023:
1946:
1934:
1925:
1916:
1907:
1898:
1889:
1880:
1879:
1871:
1862:
1853:
1729:
1608:
1542:
1536:
1469:
1452:
1449:
1399:
1335:
1305:
1288:
1207:
1189:
1121:
1104:
1028:paleontologists
992:
918:
880:
751:
733:
719:
691:
667:
608:
591:
501:) and extinct (
407:
383:
379:
336:Yunnanozoonidae
310:Palaeospondylus
243:
186:
130:
127:
126:
121:
116:
111:
106:
101:
96:
91:
86:
81:
76:
71:
60:
59:
58:
50:
39:
28:
23:
22:
15:
12:
11:
5:
6859:
6857:
6849:
6848:
6843:
6838:
6833:
6828:
6823:
6813:
6812:
6806:
6805:
6803:
6802:
6789:
6779:
6766:
6753:
6740:
6731:Fauna Europaea
6727:
6714:
6701:
6686:
6670:
6668:
6662:
6661:
6656:
6647:
6646:
6643:
6640:
6639:
6637:
6636:
6631:
6626:
6620:
6618:
6614:
6613:
6611:
6610:
6605:
6604:
6603:
6598:
6593:
6588:
6583:
6572:
6570:
6566:
6565:
6562:
6561:
6558:
6557:
6555:
6554:
6553:
6552:
6547:
6542:
6537:
6523:
6522:
6521:
6520:
6509:
6508:
6507:
6506:
6495:
6494:
6483:
6481:
6475:
6474:
6472:
6471:
6470:
6469:
6464:
6459:
6457:Porolepiformes
6446:
6441:
6432:
6430:
6421:
6415:
6414:
6412:
6411:
6410:
6409:
6404:
6402:Symmoriiformes
6398:
6392:
6386:
6384:Eugeneodontida
6374:
6373:
6372:
6371:
6366:
6361:
6355:
6349:
6343:
6335:Elasmobranchii
6331:
6329:
6323:
6322:
6320:
6319:
6313:
6307:
6304:Climatiiformes
6300:
6293:
6291:
6282:
6281:
6279:
6278:
6271:
6264:
6262:Acanthothoraci
6258:
6252:
6246:
6240:
6238:Petalichthyida
6234:
6228:
6222:
6215:
6213:
6201:
6195:
6194:
6191:
6190:
6188:
6187:
6186:
6185:
6179:
6173:
6161:
6155:
6149:
6142:
6140:
6131:
6130:
6128:
6127:
6121:
6115:
6112:Protoconodonta
6107:
6105:
6098:
6097:
6095:
6094:
6093:
6092:
6082:
6076:
6074:
6065:
6058:
6057:
6005:
6003:
6001:
6000:
5999:
5998:
5987:
5983:Myllokunmingia
5960:
5955:
5940:
5939:
5938:
5933:
5918:
5917:
5916:
5902:
5900:
5894:
5893:
5891:
5890:
5885:
5879:
5876:
5875:
5870:
5868:
5867:
5860:
5853:
5845:
5836:
5835:
5833:
5832:
5826:
5818:
5812:
5803:
5800:
5799:
5796:
5795:
5792:
5791:
5788:
5787:
5784:
5783:
5780:
5779:
5776:
5775:
5772:
5771:
5768:
5767:
5764:
5763:
5760:
5759:
5757:
5756:
5751:
5744:
5742:
5733:
5732:
5725:
5723:
5717:
5716:
5714:
5713:
5707:
5700:
5698:
5689:
5681:
5680:
5678:
5677:
5671:
5665:
5657:
5656:
5654:
5653:
5647:
5641:
5633:
5632:
5630:
5629:
5622:
5616:
5608:
5607:
5605:
5604:
5597:
5591:
5579:
5578:
5576:
5575:
5569:
5563:
5551:
5550:
5548:
5547:
5541:
5535:
5523:
5522:
5519:
5518:
5516:
5515:
5510:
5504:
5502:
5489:
5481:
5480:
5477:
5476:
5473:
5472:
5469:
5468:
5465:
5464:
5462:
5461:
5455:
5452:Phlebobranchia
5448:
5442:
5436:
5435:
5433:
5432:
5427:
5420:
5414:
5410:
5409:
5407:
5406:
5400:
5394:
5377:
5369:
5368:
5365:
5364:
5362:
5361:
5355:
5353:
5343:
5342:
5340:
5339:
5333:
5327:
5320:
5317:
5316:
5309:
5307:
5306:
5299:
5292:
5284:
5277:
5276:
5217:
5163:
5133:
5126:
5108:
5101:
5077:
5070:
5050:
5043:
5023:
4964:
4932:
4916:
4889:(2): 191–251.
4873:
4866:
4846:
4809:
4758:
4706:
4671:(2): 227–235.
4655:
4620:
4577:
4557:(4): 429–432.
4537:
4510:
4483:(8): 725–735.
4467:
4441:
4375:
4310:
4289:
4259:
4240:(6): 536–543.
4224:
4159:
4137:
4114:
4093:
4077:
4020:
3977:
3934:
3865:
3804:
3752:
3712:
3661:
3600:
3589:
3554:
3519:(4): 659–666.
3495:
3493:
3490:
3489:
3488:
3483:
3477:
3470:
3467:
3463:
3462:
3456:
3455:
3451:
3450:
3448:
3444:
3443:
3440:
3439:
3435:
3434:
3431:
3430:
3426:
3425:
3422:
3421:
3417:
3416:
3413:
3412:
3408:
3407:
3404:
3403:
3399:
3398:
3395:
3394:
3390:
3389:
3386:
3385:
3373:
3370:
3369:
3366:
3365:
3361:
3360:
3357:
3356:
3352:
3351:
3348:
3347:
3343:
3342:
3339:
3338:
3334:
3333:
3330:
3329:
3316:
3313:
3312:
3309:
3308:
3295:
3290:
3288:
3285:
3284:
3281:
3280:
3267:
3262:
3260:
3257:
3256:
3253:
3252:
3244:Cephalaspidida
3239:
3234:
3232:
3229:
3228:
3225:
3224:
3216:Ateleaspididae
3211:
3206:
3204:
3195:
3193:
3190:
3189:
3186:
3185:
3172:
3167:
3165:
3162:
3161:
3158:
3157:
3153:
3152:
3149:
3148:
3144:
3143:
3140:
3139:
3131:
3128:
3127:
3124:
3123:
3115:
3110:
3108:
3101:
3100:
3097:
3096:
3082:
3077:
3075:
3066:
3064:
3061:
3060:
3057:
3056:
3052:
3051:
3048:
3047:
3034:
3031:
3030:
3027:
3026:
3013:
3010:
3009:
3006:
3005:
2992:
2987:
2985:
2976:
2974:
2971:
2970:
2967:
2966:
2963:
2962:
2956:
2955:
2952:
2951:
2947:
2946:
2943:
2942:
2938:
2937:
2934:
2933:
2929:
2928:
2925:
2924:
2920:
2919:
2916:
2915:
2911:
2910:
2907:
2906:
2893:
2890:
2889:
2886:
2885:
2872:
2867:
2865:
2862:
2861:
2858:
2857:
2849:Tolypelepidida
2844:
2841:
2840:
2837:
2836:
2823:
2818:
2816:
2813:
2812:
2809:
2808:
2800:
2797:
2796:
2793:
2792:
2779:
2776:
2775:
2772:
2771:
2758:
2755:
2754:
2751:
2750:
2742:
2737:
2735:
2728:
2727:
2724:
2723:
2715:
2712:
2711:
2708:
2707:
2703:
2702:
2699:
2698:
2690:
2687:
2686:
2683:
2682:
2669:
2664:
2662:
2653:
2651:
2644:
2643:
2640:
2639:
2626:
2621:
2619:
2616:
2615:
2612:
2611:
2603:
2598:
2597:
2596:
2594:
2588:
2587:
2585:
2580:
2579:
2578:
2572:
2563:
2561:
2558:
2557:
2554:
2553:
2549:
2548:
2545:
2544:
2540:
2539:
2536:
2535:
2531:
2530:
2527:
2526:
2514:
2511:
2510:
2507:
2506:
2494:
2489:
2487:
2481:
2480:
2477:
2476:
2473:
2472:
2466:
2465:
2462:
2461:
2457:
2456:
2453:
2452:
2448:
2447:
2444:
2443:
2439:
2438:
2435:
2434:
2430:
2429:
2426:
2425:
2421:
2420:
2417:
2416:
2412:
2411:
2408:
2407:
2399:
2396:
2395:
2392:
2391:
2383:
2378:
2376:
2373:
2372:
2369:
2368:
2355:
2350:
2348:
2345:
2344:
2341:
2340:
2337:Paracordylodus
2332:
2327:
2325:
2323:Prioniodontida
2318:
2317:
2314:
2313:
2309:
2308:
2305:
2304:
2296:
2293:
2292:
2289:
2288:
2280:
2275:
2273:
2268:
2266:
2259:
2258:
2255:
2254:
2251:Proconodontida
2246:
2241:
2239:
2236:
2235:
2232:
2231:
2223:
2218:
2216:
2211:
2210:
2209:
2207:
2201:
2200:
2198:
2193:
2192:
2191:
2185:
2176:
2174:
2171:
2170:
2167:
2166:
2163:
2162:
2156:
2155:
2152:
2151:
2147:
2146:
2143:
2142:
2138:
2137:
2134:
2133:
2125:Birkeniiformes
2120:
2117:
2116:
2113:
2112:
2104:
2099:
2097:
2090:
2089:
2086:
2085:
2077:Jamoytiiformes
2072:
2069:
2068:
2065:
2064:
2051:
2046:
2044:
2039:
2038:
2037:
2035:
2029:
2028:
2026:
2021:
2020:
2019:
2013:
2011:Anaspidomorphi
2004:
2002:
1997:
1995:
1992:
1991:
1988:
1987:
1974:
1969:
1967:
1958:
1943:
1942:
1936:
1935:
1931:
1930:
1927:
1926:
1922:
1921:
1918:
1917:
1913:
1912:
1909:
1908:
1904:
1903:
1900:
1899:
1895:
1894:
1891:
1890:
1886:
1885:
1882:
1881:
1875:
1874:
1872:
1868:
1867:
1864:
1863:
1859:
1858:
1855:
1854:
1850:
1849:
1846:
1845:
1837:
1834:
1833:
1830:
1829:
1821:
1816:
1814:
1811:
1810:
1807:
1806:
1798:
1793:
1791:
1788:
1787:
1784:
1783:
1775:
1770:
1768:
1763:
1761:
1758:
1757:
1754:
1753:
1745:
1740:
1738:
1735:
1734:
1731:
1730:
1726:
1725:
1722:
1721:
1713:
1710:
1709:
1706:
1705:
1697:
1694:
1693:
1690:
1689:
1686:Jamoytiiformes
1681:
1676:
1674:
1672:Anaspidomorphi
1666:
1664:
1660:
1659:
1656:
1655:
1647:
1642:
1640:
1637:
1636:
1633:
1632:
1624:
1619:
1617:
1614:
1613:
1610:
1609:
1605:
1604:
1601:
1600:
1592:
1589:
1588:
1585:
1584:
1572:
1567:
1565:
1557:
1555:
1546:
1535:
1532:
1529:
1528:
1470:
1463:
1456:
1444:
1443:
1432:Early Silurian
1410:
1403:
1393:
1392:
1352:(nipple teeth)
1346:
1339:
1329:
1328:
1306:
1299:
1292:
1281:
1275:
1274:
1263:early Triassic
1223:filter feeders
1208:
1201:
1194:
1181:
1175:
1174:
1164:Myllokunmingia
1122:
1115:
1108:
1097:
1091:
1090:
1083:Jamoytiiformes
993:
988:
981:
975:
974:
948:; hagfish are
946:living fossils
924:(hagfish) are
919:
914:
907:
902:
896:
895:
892:
889:
879:
878:Classification
876:
813:are often used
786:Myllokunmingia
741:Michael Benton
732:
729:
718:
715:
690:
687:
673:. The skin of
666:
663:
607:
604:
593:Agnathans are
590:
587:
533:Molecular data
371:
370:
369:
368:
359:
358:
351:
350:
349:
348:
339:
332:
326:
320:
314:
305:
299:
290:
283:
277:
271:
265:
263:Anaspidomorphi
256:
255:
251:
250:
238:
234:
233:
228:
224:
223:
218:
214:
213:
208:
204:
203:
198:
194:
193:
180:
179:
162:
161:
153:
152:
141:
140:
132:
131:
122:
117:
112:
107:
102:
97:
92:
87:
82:
77:
72:
67:
66:
47:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
6858:
6847:
6844:
6842:
6839:
6837:
6834:
6832:
6829:
6827:
6824:
6822:
6819:
6818:
6816:
6799:
6794:
6790:
6786:
6780:
6776:
6771:
6767:
6763:
6758:
6754:
6750:
6745:
6741:
6737:
6732:
6728:
6724:
6719:
6715:
6711:
6706:
6702:
6697:
6691:
6687:
6682:
6676:
6672:
6671:
6669:
6667:
6663:
6659:
6654:
6641:
6635:
6632:
6630:
6627:
6625:
6622:
6621:
6619:
6615:
6609:
6606:
6602:
6599:
6597:
6594:
6592:
6591:cartilaginous
6589:
6587:
6584:
6582:
6579:
6578:
6577:
6574:
6573:
6571:
6567:
6551:
6548:
6546:
6543:
6541:
6538:
6536:
6530:
6529:
6528:
6525:
6524:
6519:
6516:
6515:
6514:
6511:
6510:
6505:
6502:
6501:
6500:
6497:
6496:
6492:
6485:
6484:
6482:
6480:
6476:
6468:
6465:
6463:
6460:
6458:
6452:
6451:
6450:
6447:
6445:
6442:
6440:
6434:
6433:
6431:
6429:
6425:
6422:
6420:
6416:
6408:
6405:
6403:
6399:
6397:
6393:
6391:
6387:
6385:
6381:
6380:
6379:
6376:
6375:
6370:
6367:
6365:
6362:
6360:
6356:
6354:
6350:
6348:
6344:
6342:
6338:
6337:
6336:
6333:
6332:
6330:
6328:
6327:Cartilaginous
6324:
6318:
6314:
6312:
6308:
6305:
6301:
6299:
6295:
6294:
6292:
6290:
6283:
6276:
6275:Stensioellida
6272:
6269:
6265:
6263:
6259:
6257:
6253:
6251:
6250:Ptyctodontida
6247:
6245:
6241:
6239:
6235:
6233:
6229:
6227:
6223:
6221:
6217:
6216:
6214:
6212:
6205:
6202:
6200:
6196:
6184:
6180:
6178:
6174:
6172:
6168:
6167:
6166:
6162:
6160:
6156:
6154:
6150:
6148:
6144:
6143:
6141:
6139:
6132:
6126:
6122:
6120:
6116:
6113:
6109:
6108:
6106:
6099:
6091:
6088:
6087:
6086:
6083:
6081:
6078:
6077:
6075:
6073:
6069:
6066:
6063:
6059:
6053:
6050:
6044:
6039:
6034:
6028:
6022:
6016:
6009:
5996:
5995:
5994:Zhongxiniscus
5988:
5985:
5984:
5976:
5975:
5974:Haikouichthys
5967:
5961:
5959:
5956:
5954:
5953:
5946:
5945:
5944:
5941:
5937:
5934:
5932:
5931:
5924:
5923:
5922:
5919:
5915:
5914:
5907:
5906:
5905:Basal member
5904:
5903:
5901:
5899:
5895:
5889:
5886:
5884:
5881:
5880:
5877:
5873:
5866:
5861:
5859:
5854:
5852:
5847:
5846:
5843:
5830:
5827:
5825:
5824:
5819:
5817:
5816:Sarcopterygii
5813:
5811:
5810:
5805:
5804:
5801:
5755:
5752:
5749:
5746:
5745:
5743:
5741:
5737:
5730:
5727:
5726:
5724:
5722:
5721:Archelosauria
5718:
5711:
5708:
5705:
5702:
5701:
5699:
5697:
5693:
5690:
5687:
5682:
5676:
5673:
5672:
5669:
5666:
5663:
5658:
5652:
5649:
5648:
5645:
5642:
5639:
5634:
5627:
5624:
5623:
5620:
5617:
5614:
5609:
5602:
5599:
5598:
5595:
5592:
5589:
5584:Sarcopterygii
5580:
5574:
5571:
5570:
5567:
5564:
5561:
5552:
5546:
5543:
5542:
5539:
5536:
5533:
5528:Gnathostomata
5524:
5514:
5511:
5509:
5506:
5505:
5503:
5501:
5497:
5493:
5490:
5487:
5482:
5459:
5456:
5453:
5450:
5449:
5446:
5443:
5441:
5437:
5431:
5428:
5425:
5422:
5421:
5418:
5415:
5411:
5405:
5402:
5401:
5398:
5395:
5393:
5391:(Urochordata)
5385:
5381:
5378:
5375:
5370:
5360:
5357:
5356:
5354:
5352:
5348:
5344:
5338:
5337:Deuterostomia
5334:
5332:
5328:
5326:
5322:
5321:
5318:
5313:
5305:
5300:
5298:
5293:
5291:
5286:
5285:
5282:
5272:
5268:
5263:
5258:
5253:
5248:
5244:
5240:
5236:
5232:
5228:
5221:
5218:
5213:
5209:
5204:
5199:
5194:
5189:
5185:
5181:
5177:
5170:
5168:
5164:
5152:
5148:
5146:
5137:
5134:
5129:
5123:
5119:
5112:
5109:
5104:
5098:
5094:
5093:
5088:
5087:Hanken, James
5081:
5078:
5073:
5067:
5063:
5062:
5054:
5051:
5046:
5040:
5036:
5035:
5027:
5024:
5019:
5015:
5010:
5005:
5000:
4995:
4991:
4987:
4983:
4979:
4975:
4968:
4965:
4953:on 2007-10-28
4952:
4948:
4944:
4936:
4933:
4928:
4920:
4917:
4912:
4908:
4904:
4900:
4896:
4892:
4888:
4884:
4877:
4874:
4869:
4863:
4859:
4858:
4850:
4847:
4842:
4838:
4834:
4830:
4826:
4822:
4821:
4813:
4810:
4805:
4801:
4796:
4795:11577/3479836
4791:
4786:
4781:
4777:
4773:
4769:
4762:
4759:
4754:
4750:
4745:
4740:
4736:
4732:
4728:
4724:
4717:
4710:
4707:
4702:
4698:
4694:
4690:
4686:
4682:
4678:
4674:
4670:
4666:
4659:
4656:
4651:
4647:
4643:
4639:
4635:
4631:
4624:
4621:
4616:
4612:
4608:
4604:
4600:
4596:
4592:
4588:
4581:
4578:
4565:
4560:
4556:
4552:
4548:
4541:
4538:
4533:
4529:
4525:
4521:
4514:
4511:
4506:
4502:
4498:
4494:
4490:
4486:
4482:
4478:
4471:
4468:
4457:on 2017-12-15
4456:
4452:
4445:
4442:
4437:
4433:
4428:
4423:
4419:
4415:
4411:
4407:
4403:
4399:
4395:
4391:
4387:
4379:
4376:
4371:
4367:
4362:
4357:
4353:
4349:
4345:
4341:
4337:
4333:
4329:
4325:
4321:
4314:
4311:
4300:
4296:
4292:
4290:9780123876645
4286:
4282:
4278:
4274:
4270:
4263:
4260:
4255:
4251:
4247:
4243:
4239:
4235:
4228:
4225:
4217:
4213:
4209:
4205:
4201:
4197:
4193:
4189:
4185:
4181:
4177:
4170:
4163:
4160:
4156:
4152:
4148:
4141:
4138:
4134:
4133:0-632-05637-1
4130:
4126:
4125:
4118:
4115:
4103:
4097:
4094:
4090:
4086:
4081:
4078:
4073:
4069:
4064:
4059:
4055:
4051:
4047:
4043:
4039:
4035:
4031:
4024:
4021:
4016:
4012:
4008:
4004:
4000:
3996:
3992:
3988:
3981:
3978:
3973:
3969:
3965:
3961:
3957:
3953:
3949:
3945:
3938:
3935:
3931:
3929:
3923:
3919:
3914:
3909:
3904:
3899:
3895:
3891:
3887:
3883:
3879:
3872:
3870:
3866:
3861:
3857:
3853:
3849:
3844:
3839:
3835:
3831:
3827:
3823:
3819:
3815:
3808:
3805:
3800:
3796:
3792:
3788:
3784:
3780:
3777:(2): 184–92.
3776:
3772:
3768:
3761:
3759:
3757:
3753:
3748:
3744:
3740:
3736:
3732:
3728:
3721:
3719:
3717:
3713:
3708:
3704:
3699:
3694:
3689:
3684:
3680:
3676:
3672:
3665:
3662:
3657:
3653:
3648:
3643:
3638:
3633:
3629:
3625:
3621:
3617:
3616:
3611:
3604:
3601:
3598:
3593:
3590:
3585:
3581:
3577:
3573:
3569:
3565:
3564:Palaeontology
3558:
3555:
3550:
3546:
3542:
3538:
3534:
3530:
3526:
3522:
3518:
3514:
3507:
3500:
3497:
3491:
3487:
3484:
3481:
3478:
3476:
3475:Gnathostomata
3473:
3472:
3468:
3461:
3458:
3457:
3442:
3441:
3433:
3432:
3424:
3423:
3415:
3414:
3406:
3405:
3397:
3396:
3388:
3387:
3384:
3382:
3378:
3372:
3371:
3368:
3367:
3359:
3358:
3350:
3349:
3341:
3340:
3332:
3331:
3328:
3326:
3322:
3315:
3314:
3311:
3310:
3307:
3305:
3301:
3294:
3293:
3287:
3286:
3283:
3282:
3279:
3277:
3273:
3266:
3265:
3259:
3258:
3255:
3254:
3251:
3249:
3245:
3238:
3237:
3231:
3230:
3227:
3226:
3223:
3221:
3217:
3210:
3209:
3203:
3199:
3198:
3192:
3191:
3188:
3187:
3184:
3182:
3178:
3171:
3170:
3164:
3163:
3160:
3159:
3151:
3150:
3142:
3141:
3138:
3137:
3130:
3129:
3126:
3125:
3122:
3121:
3114:
3113:
3107:
3103:
3102:
3099:
3098:
3095:
3094:
3092:
3088:
3081:
3080:
3074:
3070:
3069:
3063:
3062:
3059:
3058:
3050:
3049:
3046:
3044:
3040:
3033:
3032:
3029:
3028:
3025:
3023:
3019:
3012:
3011:
3008:
3007:
3004:
3002:
2998:
2991:
2990:
2984:
2980:
2979:
2973:
2972:
2969:
2968:
2954:
2953:
2945:
2944:
2936:
2935:
2927:
2926:
2918:
2917:
2909:
2908:
2905:
2903:
2899:
2892:
2891:
2888:
2887:
2884:
2882:
2878:
2871:
2870:
2864:
2863:
2860:
2859:
2856:
2854:
2850:
2843:
2842:
2839:
2838:
2835:
2833:
2829:
2822:
2821:
2815:
2814:
2811:
2810:
2807:
2806:
2799:
2798:
2795:
2794:
2791:
2789:
2785:
2778:
2777:
2774:
2773:
2770:
2768:
2764:
2757:
2756:
2753:
2752:
2749:
2748:
2741:
2740:
2734:
2730:
2729:
2726:
2725:
2722:
2721:
2714:
2713:
2710:
2709:
2701:
2700:
2697:
2696:
2689:
2688:
2685:
2684:
2681:
2679:
2675:
2668:
2667:
2661:
2657:
2656:
2650:
2646:
2645:
2642:
2641:
2638:
2636:
2632:
2625:
2624:
2618:
2617:
2614:
2613:
2610:
2609:
2602:
2601:
2595:
2586:
2577:
2576:
2571:
2567:
2566:
2560:
2559:
2556:
2555:
2547:
2546:
2538:
2537:
2529:
2528:
2525:
2523:
2519:
2513:
2512:
2509:
2508:
2505:
2503:
2499:
2493:
2492:
2486:
2483:
2482:
2479:
2478:
2464:
2463:
2455:
2454:
2446:
2445:
2437:
2436:
2428:
2427:
2419:
2418:
2410:
2409:
2406:
2405:
2398:
2397:
2394:
2393:
2390:
2389:
2388:Prioniodinida
2382:
2381:
2375:
2374:
2371:
2370:
2367:
2365:
2361:
2360:Balognathidae
2354:
2353:
2347:
2346:
2343:
2342:
2339:
2338:
2331:
2330:
2324:
2320:
2319:
2316:
2315:
2307:
2306:
2303:
2302:
2295:
2294:
2291:
2290:
2287:
2286:
2279:
2278:
2272:
2271:
2265:
2261:
2260:
2257:
2256:
2253:
2252:
2245:
2244:
2238:
2237:
2234:
2233:
2230:
2229:
2222:
2221:
2215:
2214:
2208:
2199:
2190:
2189:
2184:
2180:
2179:
2173:
2172:
2169:
2168:
2154:
2153:
2145:
2144:
2136:
2135:
2132:
2130:
2126:
2119:
2118:
2115:
2114:
2111:
2110:
2103:
2102:
2096:
2092:
2091:
2088:
2087:
2084:
2082:
2078:
2071:
2070:
2067:
2066:
2063:
2061:
2057:
2050:
2049:
2043:
2042:
2036:
2027:
2018:
2017:
2012:
2008:
2007:
2001:
2000:
1994:
1993:
1990:
1989:
1986:
1984:
1980:
1973:
1972:
1965:
1962:
1961:
1957:
1955:
1950:
1941:
1938:
1937:
1929:
1928:
1920:
1919:
1911:
1910:
1902:
1901:
1893:
1892:
1884:
1883:
1878:
1866:
1865:
1857:
1856:
1848:
1847:
1844:
1842:
1841:Gnathostomata
1836:
1835:
1832:
1831:
1828:
1827:
1820:
1819:
1813:
1812:
1809:
1808:
1805:
1804:
1797:
1796:
1790:
1789:
1786:
1785:
1782:
1781:
1774:
1773:
1767:
1766:
1760:
1759:
1756:
1755:
1752:
1751:
1744:
1743:
1737:
1736:
1733:
1732:
1724:
1723:
1720:
1719:
1712:
1711:
1708:
1707:
1704:
1703:
1696:
1695:
1692:
1691:
1688:
1687:
1680:
1679:
1673:
1670:
1669:
1662:
1661:
1658:
1657:
1654:
1653:
1646:
1645:
1639:
1638:
1635:
1634:
1631:
1630:
1623:
1622:
1616:
1615:
1612:
1611:
1603:
1602:
1599:
1597:
1591:
1590:
1587:
1586:
1583:
1581:
1577:
1571:
1570:
1564:
1561:
1560:
1553:
1550:
1549:
1545:
1541:
1533:
1527:
1523:
1519:
1516:
1512:
1508:
1504:
1500:
1496:
1492:
1488:
1484:
1483:
1478:
1474:
1471:
1468:
1467:
1461:
1457:
1451:
1448:Cephalaspido-
1446:
1445:
1441:
1437:
1433:
1429:
1425:
1421:
1417:
1414:
1411:
1408:
1404:
1398:
1395:
1394:
1390:
1386:
1382:
1378:
1374:
1370:
1366:
1362:
1358:
1353:
1350:
1347:
1344:
1340:
1334:
1331:
1330:
1327:
1325:
1321:
1317:
1310:
1307:
1304:
1303:
1297:
1293:
1287:
1284:
1282:
1280:
1276:
1272:
1268:
1264:
1260:
1256:
1255:Carboniferous
1252:
1248:
1244:
1240:
1236:
1232:
1228:
1224:
1220:
1216:
1212:
1209:
1206:
1205:
1199:
1195:
1193:
1188:
1184:
1182:
1180:
1176:
1172:
1171:
1166:
1165:
1160:
1159:
1158:Haikouichthys
1154:
1150:
1146:
1142:
1138:
1135:
1131:
1127:
1123:
1120:
1119:
1118:Haikouichthys
1113:
1109:
1103:
1100:
1098:
1096:
1092:
1088:
1084:
1080:
1076:
1072:
1068:
1064:
1060:
1056:
1052:
1048:
1044:
1040:
1037:
1033:
1029:
1026:Period. Some
1025:
1021:
1017:
1016:
1011:
1010:
1005:
1001:
997:
994:
991:
986:
982:
980:
977:
976:
972:
968:
964:
960:
956:
951:
947:
943:
939:
935:
931:
927:
923:
920:
917:
912:
908:
906:
903:
901:
897:
893:
890:
886:
877:
875:
873:
867:
865:
861:
857:
853:
852:osteostracans
849:
845:
841:
837:
833:
829:
825:
820:
818:
817:index fossils
814:
810:
806:
802:
798:
797:Burgess Shale
794:
793:
788:
787:
782:
781:
780:Haikouichthys
776:
772:
768:
764:
760:
756:
750:
742:
737:
730:
728:
725:
716:
714:
712:
708:
704:
703:osteostracans
700:
696:
688:
686:
684:
680:
676:
672:
665:Body covering
664:
662:
660:
656:
653:
652:cartilaginous
649:
645:
641:
637:
633:
629:
625:
621:
617:
613:
605:
603:
600:
599:Anticoagulant
596:
588:
586:
584:
580:
577:
573:
569:
564:
562:
558:
554:
550:
546:
545:embryological
542:
538:
534:
530:
528:
524:
520:
516:
512:
508:
504:
500:
496:
493:
489:
486:
482:
478:
475:
471:
468:
461:
457:
454:
451:
444:
440:
437:
436:Ancient Greek
431:
377:
366:
365:Gnathostomata
363:
362:
360:
356:
355:Cladistically
352:
346:
345:
344:Zhongxiniscus
340:
337:
333:
331:
327:
325:
321:
319:
315:
312:
311:
306:
304:
300:
297:
296:
295:Metaspriggina
291:
288:
284:
282:
278:
275:
272:
270:
266:
264:
260:
259:
257:
252:
247:
242:
239:
237:Infraphylum:
236:
235:
232:
229:
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225:
222:
219:
216:
215:
212:
209:
206:
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202:
199:
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177:
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125:
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110:
105:
100:
95:
90:
85:
80:
75:
70:
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53:
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41:
37:
33:
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6665:
6581:spiny sharks
6540:Halecomorphi
6359:Xenacanthida
6244:Phyllolepida
6177:Pituriaspida
6138:Ostracoderms
6072:Cyclostomata
6062:Jawless fish
6061:
6011:
5992:
5981:
5972:
5950:
5928:
5911:
5828:
5821:
5807:
5754:Aves (birds)
5696:Lepidosauria
5556:Euteleostomi
5500:Cyclostomata
5335:Superphylum
5234:
5230:
5220:
5183:
5179:
5154:. Retrieved
5150:
5144:
5136:
5117:
5111:
5091:
5080:
5060:
5053:
5033:
5026:
4981:
4977:
4967:
4955:. Retrieved
4951:the original
4946:
4943:"Thelodonti"
4935:
4919:
4886:
4882:
4876:
4856:
4849:
4824:
4818:
4812:
4775:
4771:
4761:
4726:
4722:
4709:
4668:
4664:
4658:
4633:
4629:
4623:
4590:
4586:
4580:
4568:. Retrieved
4554:
4550:
4540:
4523:
4519:
4513:
4480:
4476:
4470:
4459:. Retrieved
4455:the original
4444:
4393:
4389:
4378:
4330:(1): 33760.
4327:
4323:
4313:
4302:. Retrieved
4272:
4262:
4237:
4233:
4227:
4179:
4175:
4162:
4154:
4146:
4140:
4123:
4117:
4106:. Retrieved
4096:
4088:
4080:
4037:
4033:
4023:
3990:
3986:
3980:
3947:
3943:
3937:
3927:
3925:
3885:
3881:
3817:
3813:
3807:
3774:
3770:
3766:
3730:
3726:
3678:
3674:
3664:
3619:
3613:
3603:
3592:
3567:
3563:
3557:
3516:
3512:
3499:
3486:Cyclostomata
3377:Gnathostomes
3375:
3318:
3297:
3269:
3241:
3213:
3177:Pituriaspida
3174:
3133:
3117:
3084:
3036:
3015:
2994:
2895:
2874:
2846:
2825:
2805:Corvaspidida
2802:
2781:
2760:
2744:
2733:Heterostraci
2720:Eriptychiida
2717:
2692:
2671:
2628:
2605:
2516:
2496:
2404:Ozarkodinida
2401:
2385:
2357:
2334:
2301:Panderontida
2298:
2282:
2248:
2225:
2122:
2106:
2074:
2053:
1976:
1953:
1951:
1947:
1839:
1823:
1803:Pituriaspida
1800:
1777:
1747:
1715:
1699:
1683:
1663:Myopterygii
1649:
1626:
1594:
1582:(hagfishes)
1574:
1563:Cyclostomata
1543:
1526:Pituriaspida
1507:lateral line
1480:
1477:osteostracan
1464:
1415:
1387:of the Late
1373:Heterostraci
1351:
1316:Heterostraci
1313:
1300:
1279:Ostracoderms
1202:
1185:
1168:
1162:
1156:
1116:
1079:monophyletic
1047:Cyclostomata
1032:ostracoderms
1013:
1007:
967:gnathostomes
929:
868:
824:Ostracoderms
821:
790:
784:
778:
752:
720:
717:Reproduction
707:pituriaspids
692:
668:
632:pineal gland
609:
592:
565:
535:, both from
531:
527:gnathostomes
511:ostracoderms
481:jawless fish
480:
466:
463:
456:
449:
446:
439:
375:
374:
342:
318:Pituriaspida
308:
293:
240:
169:
40:
6690:Wikispecies
6601:lobe-finned
6527:Neopterygii
6513:Chondrostei
6449:Rhipidistia
6428:Lobe-finned
6378:Holocephali
6183:Osteostraci
6085:Hyperoartia
5930:Cathaymyrus
5898:Forerunners
5740:Archosauria
5613:Rhipidistia
5329:(unranked)
5180:BMC Biology
5156:30 December
4957:October 30,
4947:Palaeos.com
3202:Osteostraci
2631:Arandaspida
2264:Euconodonta
2109:Endeiolepis
2056:Euphanerida
1826:Osteostraci
1702:Euphanerida
1598:(lampreys)
1576:Hyperotreti
1518:Osteostraci
1482:Cephalaspis
1324:Arandaspida
1137:lagerstätte
1063:vertebrates
1015:Euphanerops
1009:Endeiolepis
996:Hyperoartia
979:Hyperoartia
963:vertebrates
959:cyclostomes
900:Cyclostomes
834:(including
648:ectothermic
595:ectothermic
543:as well as
525:, known as
499:cyclostomes
477:vertebrates
474:gnathostome
434:; from
303:Osteostraci
227:Subphylum:
61:518–0
6831:Infraphyla
6815:Categories
6586:placoderms
6545:Ginglymodi
6479:Ray-finned
6444:Coelacanth
6289:Acanthodii
6226:Arthrodira
6211:Placoderms
6199:Jawed fish
6171:Galeaspida
6153:Thelodonti
5952:Haikouella
5943:Olfactores
5486:Vertebrata
5440:Enterogona
5374:Olfactores
4729:: 103325.
4461:2013-02-21
4304:2019-12-03
4108:2013-06-30
4085:Romer, A.S
4040:(6): 373.
3492:References
3480:Amphirhina
3321:Thyestiida
3073:Galeaspida
2983:Thelodonti
2660:Astraspida
2608:Anatolepis
2485:Cyclostomi
1964:Vertebrata
1780:Galeaspida
1750:Thelodonti
1552:Vertebrata
1538:See also:
1522:Galeaspida
1428:hypocercal
1381:Ordovician
1361:jawed fish
1349:Thelodonti
1333:Thelodonti
1320:Astraspida
1231:phosphatic
1204:Panderodus
1057:among the
1002:and their
965:alongside
936:but not a
930:slime eels
856:galeaspids
848:thelodonts
840:Ordovician
792:Haikouella
767:vertebrate
747:See also:
699:caudal fin
689:Appendages
657:, and the
644:appendages
628:pineal eye
606:Morphology
589:Metabolism
579:Vertebrata
561:Cyclostomi
557:jawed fish
495:Vertebrata
281:Galeaspida
274:Cyclostomi
231:Vertebrata
150:Cyclostomi
6644:† extinct
6499:Cladistia
6256:Rhenanida
6220:Antiarchi
6125:Conodonta
6104:Conodonts
5638:Tetrapoda
5331:Bilateria
5186:(1): 39.
5092:The Skull
4804:2296-701X
4753:225005180
4636:: 36–43.
4570:3 January
4418:1476-4687
4352:2045-2322
4204:0022-3360
4151:Macmillan
4102:"Hagfish"
3549:135091168
3541:0016-7649
3272:Zenaspida
2183:Conodonta
1629:Conodonta
1534:Phylogeny
1454:(extinct)
1401:(extinct)
1337:(extinct)
1302:Astraspis
1290:(extinct)
1243:Wisconsin
1211:Conodonts
1191:(extinct)
1179:Conodonta
1153:cartilage
1149:hard bone
1145:craniates
1106:(extinct)
1075:conodonts
955:lancelets
894:Comments
888:Subgroup
860:conodonts
832:tetrapods
828:bony fish
805:Conodonts
759:Paleozoic
731:Evolution
620:notochord
576:subphylum
549:hagfishes
539:and from
503:conodonts
492:subphylum
483:, in the
269:Conodonta
207:Kingdom:
201:Eukaryota
171:Pteraspis
6723:55867450
6675:Wikidata
6462:Lungfish
6407:Chimaera
6159:Anaspida
5958:Tunicate
5936:Lancelet
5388:Tunicata
5325:Animalia
5323:Kingdom
5312:chordate
5271:30670644
5212:29653534
5145:Chordata
5089:(1993).
5018:28241029
4978:PLOS ONE
4911:22803015
4903:10881388
4701:53395896
4551:Episodes
4505:85163902
4436:38262590
4427:10972751
4370:27762335
4299:21569914
4254:19121930
4216:Archived
4212:53395896
4072:21712821
3922:21041649
3852:23254938
3799:11820840
3707:20959416
3656:25923521
3615:PLOS One
3469:See also
3460:Craniata
2518:Lampreys
2095:Anaspida
1940:Craniata
1718:Anaspida
1499:Mesozoic
1495:Silurian
1491:lampreys
1466:Thyestes
1440:lampreys
1424:Devonian
1420:Silurian
1413:Anaspida
1397:Anaspida
1389:Devonian
1377:Anaspida
1271:Mesozoic
1239:Scotland
1219:Jurassic
1215:Cambrian
1187:Conodont
1130:Cambrian
1081:lineage
1039:Anaspida
1024:Devonian
1000:lampreys
971:craniata
942:lampreys
891:Example
864:Devonian
844:Silurian
809:Triassic
763:Cambrian
655:skeleton
583:Craniata
568:Cambrian
553:lampreys
507:anaspids
488:Chordata
221:Chordata
217:Phylum:
211:Animalia
197:Domain:
32:Agnathia
6821:Agnatha
6762:5424564
6710:AGNATHA
6696:Agnatha
6681:Q161095
6666:Agnatha
6617:Related
6550:Teleost
6090:Lamprey
6080:Hagfish
5829:italics
5662:Amniota
5314:classes
5310:Extant
5262:6369785
5239:Bibcode
5203:5899321
5009:5328365
4986:Bibcode
4829:Bibcode
4731:Bibcode
4693:1303249
4673:Bibcode
4638:Bibcode
4615:4342260
4595:Bibcode
4526:(466).
4485:Bibcode
4398:Bibcode
4361:5071834
4332:Bibcode
4184:Bibcode
4063:3157150
4042:Bibcode
4015:1496398
3995:Bibcode
3987:Science
3972:1496398
3952:Bibcode
3944:Science
3913:2984170
3890:Bibcode
3860:4403344
3822:Bibcode
3779:Bibcode
3747:9866205
3698:2984222
3647:4418965
3624:Bibcode
3572:Bibcode
3521:Bibcode
3452:Agnatha
2590:⊟
2581:⊞
2498:Hagfish
2203:⊟
2194:⊞
2031:⊟
2022:⊞
1515:classes
1259:Permian
1227:century
990:lamprey
916:hagfish
743:, 2005.
724:cloacas
675:hagfish
642:or any
640:stomach
636:mammals
572:species
515:animals
467:gnáthos
376:Agnatha
241:Agnatha
146:lamprey
56:Present
54:–
46:Agnatha
18:Jawless
6785:175575
6782:uBio:
6749:914178
5913:Pikaia
5686:Sauria
5269:
5259:
5210:
5200:
5124:
5099:
5068:
5041:
5016:
5006:
4909:
4901:
4864:
4802:
4751:
4699:
4691:
4613:
4587:Nature
4503:
4434:
4424:
4416:
4390:Nature
4368:
4358:
4350:
4297:
4287:
4252:
4210:
4202:
4131:
4070:
4060:
4013:
3970:
3920:
3910:
3858:
3850:
3814:Nature
3797:
3745:
3705:
3695:
3654:
3644:
3547:
3539:
1580:Myxini
1524:, and
1479:genus
1450:morphi
1273:taxa.
1167:, and
1132:aged
1051:Myxini
1004:fossil
922:Myxini
905:Myxini
854:, and
836:humans
683:armour
671:scales
519:sister
509:, and
485:phylum
460:γνάθος
248:, 1889
36:Aynata
6793:WoRMS
6775:91606
6736:11998
6569:Lists
6369:Shark
5413:Acopa
4907:S2CID
4749:S2CID
4719:(PDF)
4697:S2CID
4689:JSTOR
4611:S2CID
4501:S2CID
4219:(PDF)
4208:S2CID
4172:(PDF)
3928:et al
3856:S2CID
3545:S2CID
3509:(PDF)
1954:et al
1503:gills
1487:taxon
1141:China
1055:basal
1036:class
950:basal
934:skull
775:China
755:fauna
659:heart
541:mtDNA
479:, or
438:
6798:1829
6744:ITIS
6596:bony
6419:Bony
5883:Fish
5267:PMID
5208:PMID
5158:2016
5122:ISBN
5097:ISBN
5066:ISBN
5039:ISBN
5014:PMID
4959:2007
4899:PMID
4862:ISBN
4800:ISSN
4572:2019
4432:PMID
4414:ISSN
4366:PMID
4348:ISSN
4295:PMID
4285:ISBN
4250:PMID
4200:ISSN
4129:ISBN
4068:PMID
4011:PMID
3968:PMID
3918:PMID
3848:PMID
3795:PMID
3743:PMID
3703:PMID
3652:PMID
3537:ISSN
1422:and
1375:and
1241:and
1124:The
1012:and
783:and
705:and
624:gill
616:fins
612:jaws
551:and
537:rRNA
523:jaws
246:Cope
69:PreꞒ
6718:EoL
6705:AFD
6364:Ray
5968:? (
5257:PMC
5247:doi
5235:116
5198:PMC
5188:doi
5004:PMC
4994:doi
4891:doi
4837:doi
4790:hdl
4780:doi
4739:doi
4727:195
4681:doi
4646:doi
4634:431
4603:doi
4591:374
4559:doi
4528:doi
4522:".
4493:doi
4422:PMC
4406:doi
4394:627
4356:PMC
4340:doi
4277:doi
4242:doi
4192:doi
4058:PMC
4050:doi
4003:doi
3991:257
3960:doi
3948:257
3908:PMC
3898:doi
3886:107
3838:hdl
3830:doi
3818:493
3787:doi
3735:doi
3693:PMC
3683:doi
3679:107
3642:PMC
3632:doi
3580:doi
3529:doi
3517:175
1511:jaw
1151:or
1139:in
926:eel
815:as
799:of
773:of
634:in
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6692::
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1966:/
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450:a-
443:ἀ-
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144:A
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6436:†
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