127:
729:
152:
268:
The derivation of the
Actinocerida remains enigmatic. They first appear late in the Early Ordovician (Cassinian Stage, late Floian) with the Georginidae but don't become well established until the beginning of the early Whiterockian Stage (Dapingian) of the Middle Ordovician (Flower 1868,1976) The
250:
composed of expanded segments that extend into the adjacent chambers, in which deposits formed within contain a system of radial canals and a narrow space along the inner side of the connecting ring known as a paraspatium. (Teichert 1964) Septal necks are generally short and cyrtochoanitic, some
395:
The
Actinocerida contain nine families; the Georginidae, Wutinoceratidae, Polydesmiidae, Armenoceratidae, Ormoceratidae, Actinoceratidae, Gonioceratidae, Lambeoceratide, and Huroniidae. The Carbactinoceratidae, included in the taxonomy in the Treatise, (Vol K) have been removed to the
113:
259:
The
Actinocerida inhabited shallow to quite deep waters, where they alternated between swimming and lying on the bottom. They were predatory, and able to control their buoyancy to a greater degree than their contemporaries.
376:(Lamberoceratidae) to the uppermost Middle and Upper Ordovician. The wutinocerids are known only from the early Middle Ordovician (Whiterockian) and the polydesmiadids are restricted to about that time.
629:
Flower, R.H. 1976, New
American Wutinoceratidae with Review of Actinoceroid Occurrences in Eastern Hemisphere, Memoir 28 Part I; New Mexico Bureau of Mines and Mineral Resources, Socorro, NM
320:
in
Northern Australia. They reached their greatest diversity in the Middle Ordovician with more than 20 genera, then declined somewhat in the Late Ordovician and more so in the
327:
Three major lineages began the Middle
Ordovician, the Actinoceratidae, Armenoceratidae, and Ormoceratidae. The Actinoceratidae and Armenoceratidae are most likely derived from
251:
being recumbent, some hook shaped. Most grew to lengths of about 60 to 90 cm (2.0 to 3.0 ft) but some, like the
Huroniidae of the Silurian grew significantly larger.
638:
Kröger, B. and Mapes, R. 2007; Carboniferous
Actinoceratoid Nautiloidea (Cephalopods) - A New Perspective; Journal of Paleontology; July 2007; v. 81; no. 4; p. 714-724
661:
Wade, M. 1988; Nautiloids and their descendants; Cephalopod classification in 1986. Memoir 44, pp 15–25; New Mexico Bureau of Mines and
Mineral Resources, Socorro, NM
442:
298:
324:; made a slight come back in the Middle Silurian but not to Late Ordovician numbers; and declined more or less steadily from the Late Silurian into the Devonian.
405:
281:
have been suggested as being ancestral but none are known to have gone beyond the near end of the
Cambrian extinction, which makes any connection hypothetical.
822:
368:; the Armenoceratidae and Huroniidae extend into the Upper Silurian. The Ormoceratidae are possibly the most recent, extending into the Lower Devonian
510:
620:
Flower, R.H. 1968, The First Great Expansion of the Actinoceroids, Memoir 19, Part I; New Mexico Bureau of Mines and Mineral Resources, Socorro, NM
540:
1196:
552:
437:
991:
411:
871:
400:
686:
493:
277:
Coolibah Formation of the Georgina Basin in Northern Australia. How the Georginidae relate to older stocks is unclear. The Upper Cambrian
1252:
448:
1242:
655:
316:
Actinocerids first appeared early in the Middle Ordovician, with the exception of the Georginidae, which are known from the
296:. However, it turned out based on a reassessment of Lower Ordovician and Whiterockian formations in northeastern China that
651:
Flower R.H. 1957, Studies of the Actinoceratida, Memoir 2; New Mexico Bureau of Mines and Mineral Resources, Socorro, NM
679:
383:
period actinocerids became rare; perhaps they were unable to compete with the more compact and maneuverable coiled
1257:
139:
664:
1247:
672:
151:
17:
126:
734:
728:
1214:
1187:
1149:
1237:
1209:
591:
Kroger, B; Yun-Bai, Zhang (2008). "Pulsed cephalopod diversification during the Ordovician".
1201:
498:
351:
269:
Georginidae, introduced and described by Mary Wade in 1977 (Wade 1988), based on the genus
658:, Vol K (Nautiloidea). Geol Soc of America and University of Kansas Press; pp K190– K216
8:
287:
was once thought to be the ancestral form of the actinocerids, and was derived from the
889:
146:
420:, Shimazu and Obata, 1938, ?late E - early M Ord (Whiterock); Asia, Aunt N Am. N Eur.
788:
600:
321:
278:
1030:
1013:
936:
604:
517:
481:
454:
417:
288:
1172:
1093:
997:
946:
941:
903:
317:
274:
1231:
801:
794:
221:
70:
1124:
1117:
1111:
1060:
1008:
951:
829:
815:
694:
372:(Gonioceratidae) is limited to the Middle Ordovician, its quasi-lookalike
1181:
1040:
1004:
896:
882:
864:
764:
522:
486:
459:
430:
357:
345:
333:
304:
292:
239:
45:
1104:
1098:
1067:
1054:
1050:
1036:
974:
920:
876:
843:
770:
717:
696:
545:
504:
339:
193:
90:
55:
1131:
985:
963:
850:
757:
557:
384:
247:
243:
203:
163:
95:
1143:
1166:
967:
744:
707:
380:
183:
85:
80:
65:
60:
50:
980:
808:
100:
75:
173:
112:
308:, its assumed primitive nature rather a derived condition.
225:
364:
The Actinoceratidae extend into the Lower Silurian with
387:
and ammonoids and cope with the arrival of jawed fish.
331:
and the Ormoceratidae from a second wutinocerid genus,
238:
are an order of generally straight, medium to large
593:Palaeogeography, Palaeoclimatology, Palaeoecology
1229:
590:
440:, Kobayashi 1940; ?late E- M Ord, C and E Asia;
311:
403:, Wade 1977; late E- early M Ord., Aust, Asia;
654:Teichert, Curt 1964, Actinoceratoidea, in the
390:
680:
687:
673:
125:
111:
960:First appearance of long-lasting lineages
584:
457:, Seamann 1853, ?late E, M Ord - E Sil.
343:is an offshoot of an early Armenoceras;
616:
614:
242:that lived during the early and middle
14:
1230:
379:Originating in the Ordovician, by the
1148:
1147:
668:
656:Treatise on Invertebrate Paleontology
520:, Troedsson 1926; early M Ord - Sil.
623:
611:
24:
1253:Early Ordovician first appearances
727:
645:
25:
1269:
933:Earliest unambiguous cephalopods
150:
43:
120:General form of an Actinocerid
1029:the earliest cephalopod group
715:The belemnite-cuttlefish-like
632:
13:
1:
1243:Prehistoric cephalopod orders
1088:Probable misidentified genera
1059:Earliest coiled cephalopods:
577:
312:Evolution and diversification
263:
700:(listed by first occurrence)
605:10.1016/j.palaeo.2008.12.015
7:
391:Classification and taxonomy
273:, are known from the upper
10:
1274:
973:Probable coleoid ancestor
549:(from early Armenoceratid)
254:
1156:
1081:
1022:
928:
919:
859:
839:
779:
752:
743:
725:
706:
355:are offshoots of a later
147:Scientific classification
145:
140:UW–Madison Geology Museum
134:The holotype specimen of
133:
124:
119:
110:
41:Lower Ordovician–Devonian
34:
27:Extinct order of molluscs
732:
543:, late Mid Ord, N Am.
136:Actinoceras beloitense
1210:Paleobiology Database
731:
246:, distinguished by a
1258:Devonian extinctions
1248:Paleozoic molluscs
733:
396:Pseudorthocerida.
1225:
1224:
1150:Taxon identifiers
1141:
1140:
1077:
1076:
915:
914:
823:Paleocirroteuthis
232:
231:
228:
16:(Redirected from
1265:
1218:
1217:
1205:
1204:
1192:
1191:
1190:
1177:
1176:
1175:
1145:
1144:
926:
925:
789:Muensterelloidea
750:
749:
701:
689:
682:
675:
666:
665:
639:
636:
630:
627:
621:
618:
609:
608:
599:(1–2): 174–183.
588:
555:, Seamann 1853,
511:Discoactinoceras
302:is antedated by
279:Protactinocerida
220:
215:
155:
154:
129:
115:
105:
42:
38:Temporal range:
32:
31:
21:
1273:
1272:
1268:
1267:
1266:
1264:
1263:
1262:
1228:
1227:
1226:
1221:
1213:
1208:
1200:
1195:
1186:
1185:
1180:
1171:
1170:
1165:
1152:
1142:
1137:
1073:
1031:Ellesmerocerida
1018:
1014:Phragmoteuthids
937:Plectronocerida
911:
855:
835:
775:
739:
736:
723:
702:
699:
695:Notable fossil
693:
648:
646:Further reading
643:
642:
637:
633:
628:
624:
619:
612:
589:
585:
580:
571:Troedssonoceras
518:Armenoceratidae
482:Lambeoceratidae
455:Actinoceratidae
426:Cyrtonybyoceras
418:Wutinoceratidae
393:
314:
289:ellesmeroceriid
266:
257:
219:
213:
149:
106:
104:
103:
98:
93:
88:
83:
78:
73:
68:
63:
58:
53:
48:
40:
39:
36:
28:
23:
22:
15:
12:
11:
5:
1271:
1261:
1260:
1255:
1250:
1245:
1240:
1223:
1222:
1220:
1219:
1206:
1193:
1178:
1162:
1160:
1154:
1153:
1139:
1138:
1136:
1135:
1128:
1121:
1114:
1109:
1094:Nectocarididae
1091:
1089:
1085:
1083:
1079:
1078:
1075:
1074:
1072:
1071:
1063:
1057:
1047:
1033:
1027:
1023:
1020:
1019:
1017:
1016:
1011:
1001:
998:Syllipsimopodi
977:
971:
961:
957:
956:
947:Monoplacophora
942:Plectronoceras
929:
923:
917:
916:
913:
912:
910:
909:
908:
907:
904:Belemnotheutis
900:
893:
880:
869:
867:
860:
857:
856:
854:
853:
847:
840:
837:
836:
834:
833:
826:
819:
812:
805:
798:
791:
786:
784:
783:Early coleoids
780:
777:
776:
774:
773:
767:
762:
760:
753:
747:
741:
740:
726:
724:
722:
721:
712:
710:
704:
703:
692:
691:
684:
677:
669:
663:
662:
659:
652:
647:
644:
641:
640:
631:
622:
610:
582:
581:
579:
576:
575:
574:
563:Metarmenoceras
550:
541:Gonioceratidae
538:
515:
491:
479:
469:Paractinoceras
452:
435:
415:
392:
389:
322:Early Silurian
313:
310:
265:
262:
256:
253:
230:
229:
211:
207:
206:
201:
197:
196:
191:
187:
186:
181:
177:
176:
171:
167:
166:
161:
157:
156:
143:
142:
131:
130:
122:
121:
117:
116:
108:
107:
99:
94:
89:
84:
79:
74:
69:
64:
59:
54:
49:
44:
37:
26:
9:
6:
4:
3:
2:
1270:
1259:
1256:
1254:
1251:
1249:
1246:
1244:
1241:
1239:
1236:
1235:
1233:
1216:
1211:
1207:
1203:
1198:
1194:
1189:
1183:
1179:
1174:
1168:
1164:
1163:
1161:
1159:
1155:
1151:
1146:
1134:
1133:
1129:
1127:
1126:
1122:
1120:
1119:
1115:
1113:
1110:
1107:
1106:
1101:
1100:
1095:
1092:
1090:
1087:
1086:
1084:
1082:Misidentified
1080:
1070:
1069:
1064:
1062:
1058:
1056:
1052:
1048:
1046:
1042:
1038:
1034:
1032:
1028:
1025:
1024:
1021:
1015:
1012:
1010:
1006:
1002:
1000:
999:
994:
993:
988:
987:
982:
978:
976:
972:
969:
965:
962:
959:
958:
954:
953:
948:
944:
943:
938:
934:
931:
930:
927:
924:
922:
918:
906:
905:
901:
899:
898:
894:
892:
891:
887:
886:
884:
881:
879:
878:
873:
870:
868:
866:
862:
861:
858:
852:
848:
845:
842:
841:
838:
832:
831:
827:
825:
824:
820:
818:
817:
813:
811:
810:
806:
804:
803:
802:Styletoctopus
799:
797:
796:
795:Proteroctopus
792:
790:
787:
785:
782:
781:
778:
772:
768:
766:
763:
761:
759:
755:
754:
751:
748:
746:
742:
738:
730:
720:
719:
714:
713:
711:
709:
705:
698:
690:
685:
683:
678:
676:
671:
670:
667:
660:
657:
653:
650:
649:
635:
626:
617:
615:
606:
602:
598:
594:
587:
583:
572:
568:
564:
560:
559:
554:
553:Ormoceratidae
551:
548:
547:
542:
539:
537:
533:
532:Selkirkoceras
529:
525:
524:
519:
516:
513:
512:
507:
506:
501:
500:
495:
492:
489:
488:
483:
480:
478:
474:
473:Saffordoceras
470:
466:
462:
461:
456:
453:
451:
450:
445:
444:
439:
438:Polydesmiidae
436:
433:
432:
427:
423:
419:
416:
414:
413:
408:
407:
402:
399:
398:
397:
388:
386:
382:
377:
375:
371:
367:
362:
360:
359:
354:
353:
348:
347:
342:
341:
336:
335:
330:
325:
323:
319:
309:
307:
306:
301:
300:
295:
294:
290:
286:
282:
280:
276:
272:
261:
252:
249:
245:
241:
237:
227:
223:
218:
212:
209:
208:
205:
202:
199:
198:
195:
192:
189:
188:
185:
182:
179:
178:
175:
172:
169:
168:
165:
162:
159:
158:
153:
148:
144:
141:
137:
132:
128:
123:
118:
114:
109:
102:
97:
92:
87:
82:
77:
72:
67:
62:
57:
52:
47:
33:
30:
19:
1238:Actinocerida
1188:Actinocerida
1158:Actinocerida
1157:
1130:
1125:Shelbyoceras
1123:
1118:Volborthella
1116:
1112:Kirengellida
1103:
1097:
1066:
1061:Tarphycerida
1049:Brevicones:
1045:Actinocerida
1044:
1035:Orthocones:
1009:Aulacocerids
996:
992:Gordoniconus
990:
984:
952:Knightoconus
950:
949:-like form:
940:
932:
902:
895:
888:
875:
830:Vampyronassa
828:
821:
816:Palaeoctopus
814:
807:
800:
793:
735:Evolution of
716:
634:
625:
596:
592:
586:
570:
567:Parormoceras
566:
562:
556:
544:
535:
531:
527:
521:
509:
503:
497:
485:
477:Troostoceras
476:
472:
468:
464:
458:
447:
441:
429:
425:
421:
412:Mesaktoceras
410:
404:
394:
378:
373:
369:
365:
363:
356:
350:
344:
338:
332:
328:
326:
315:
303:
297:
291:
284:
283:
270:
267:
258:
236:Actinocerida
235:
233:
217:Actinocerida
216:
135:
35:Actinocerida
29:
1182:Wikispecies
1065:Spirulid?:
1041:Orthocerida
1026:Early forms
897:Belemnopsis
872:Diplobelids
765:Nautilaceae
737:cephalopods
697:cephalopods
536:Elrodoceras
523:Armenoceras
487:Lambeoceras
460:Actinoceras
431:Adamsoceras
422:Wutinoceras
401:Georginidae
374:Lambeoceras
366:Actinoceras
358:Actinoceras
346:Lambeoceras
334:Adamsoceras
329:Wutinoceras
305:Wutinoceras
293:Bathmoceras
240:cephalopods
204:Nautiloidea
194:Cephalopoda
18:Actinocerid
1232:Categories
1105:Nectocotis
1099:Nectocaris
1068:Shimanskya
1055:Oncocerida
1051:Ascocerida
1037:Endocerida
1005:belemnoids
975:Bactritida
921:Palaeozoic
890:Belemnites
883:Belemnites
877:Diplobelus
865:belemnoids
758:nautiloids
718:Belosaepia
578:References
546:Gonioceras
528:Nybyoceras
505:Huroniella
494:Huroniidae
465:Kochoceras
443:Polydesmia
434:, ........
385:nautiloids
370:Gonioceras
340:Gonioceras
299:Polydesmia
285:Polydesmia
264:Derivation
200:Subclass:
1132:Pohlsepia
1003:Earliest
986:Jeletzkya
970:ammonoids
964:Goniatite
863:Advanced
851:Nautilida
846:ammonoids
844:Ceratitid
771:ammonites
756:Advanced
558:Ormoceras
508:, ?
449:Ordoceras
318:Cassinian
248:siphuncle
244:Paleozoic
170:Kingdom:
164:Eukaryota
1173:Q3604801
1167:Wikidata
981:coleoids
968:ceratite
745:Mesozoic
708:Cenozoic
573:........
406:Georgina
381:Devonian
275:Canadian
271:Georgina
222:Teichert
184:Mollusca
180:Phylum:
174:Animalia
160:Domain:
809:Keuppia
499:Huronia
352:Huronia
255:Ecology
210:Order:
190:Class:
979:Early
1215:12656
1202:12159
1197:IRMNG
849:late
769:True
966:and
349:and
234:The
226:1933
46:PreꞒ
1096:: (
989:?,
601:doi
597:273
569:,
534:,
138:in
1234::
1212::
1199::
1184::
1169::
1102:,
1053:,
1043:,
1039:,
1007::
995:,
983::
945:,
939::
935::
885::
874::
613:^
595:.
565:,
561:,
530:,
526:,
502:,
496:,
484:;
475:,
471:,
467:,
463:,
446:,
428:,
424:,
409:,
361:.
337:.
224:,
96:Pg
1108:)
955:?
688:e
681:t
674:v
607:.
603::
514:.
490:,
214:†
101:N
91:K
86:J
81:T
76:P
71:C
66:D
61:S
56:O
51:Ꞓ
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
