DET KONGELIGE INDUSTRI-, HÅNDVERK- OG SKIPSFARTSDEPARTEMENT
NORSK POLARINSTITUTT
SKRIFTER
Nr. 97
THE DOWNTONIAN AND DEVONIAN VERTEBRATES OF SPITSBERGEN. IX
MORPHOLOGIC AND SYSTEMATIC STUDIES OF THE SPITSBERGEN CEPHALASPIDS
RESULTS OF TH. VOGT'S EXPEDITlON 1928
AND THE ENGLlSH-NORWEGIAN-SWEDISH EXPEDITION 1939
BY
GUSTAV WXNGSJO
WITH 108 FIGURES IN THE TEXT AND 118 PLATES
A.TEXT
OSLO
I KOMMISJON HOS JACOB DYBWAD 1952
(Formerly Norges Svalbard- og Ishavs-undersøkelser.) Observatoriegaten 1, Oslo
SKRIFTER
Resultater av De Norske statsunderstøttede Spitsbergenekspeditioner.
Nr. 1. HOEL, A., The Norwegian Svalbard Expeditions 1906-1926. 1929. Kr. 10,00.
" 2. RAVN, J. P. J., On the Mollusca of the Tertiary of Spitsbergen. 1922. Kr. 1,60.
" 3. WERENSKIOLD, W. and I. OFTEDAL, A burning Coal Seam at Mt. Pyramide, Spitsbergen. 1922. Kr. 1,20.
" 4. WOLLEBÆK, A., The Spitsbergen Reindeer. 1926. Kr. 10,00.
" 5. LYNOE, B., Lichens from Spitsbergen. 1924. Kr. 2,50.
" 6. HOEL, A., The Coal Deposits and Coal Mining of Svalbard. 1925. Kr. 10,00.
[Out of print.l
.. 7. DAHL, K., Contributions to the Biology of the Spitsbergen Char. 1926. Kr. 1,00.
8. HOLTEDAHL, O., Notes on the Geology of Northwestern Spitsbergen. 1926. Kr. 5,50.
" 9. LYNOE, B., Lichens from Bear Island (Bjørnøya). 1926. Kr. 5,80.
" 10. IVERSEN, T., Hopen (Hope Island), Svalbard. 1926. Kr. 7,50.
" Il. QUENSTEDT, W., Mollusken a. d. Redbay- u. Greyhookschichten Spitzb. 1926. Kr. 8,50.
" l - I l : Vol. 1. From Nr. 12 the papers are only numbered consecutively.
Skrifter om Svalbard og Nordishavet.
Nr. 12. STENSlO, E. A:soN, The Downtonian and Devonian Vertebrates of Spitsbergen.
Nr. 13.
..
14 ." 15.
" 16.
" 17.
" 18.
19.
" 21. 20.
" 22.
..
23 ." 24.
" 25.
" 26.
" 27.
" 28.
..
29 ." 30.
" 31.
" 32.
..
33 .•
34 .Part I. Cephalaspidae. A. Text, and B. Plates. 1927. Kr. 60,00.
Skrifter om Svalbard og [shal'et.
LIND, J., The Micromycetes of Svalbard. 1928. Kr. 6,00.
KJÆR, R. and j. E. FJELDSTAD, Tidal Observations in the Arctic. 1934. Kr. 6,00.
HORN, G. and A. K. ORVIN, Geology of Bear Island. 1928. Kr. 15,00.
JELSTRUP, H. S., Determinatiofls astronomiques. 1928. Kr. 2,00.
HORN, G., Beitråge zur Kenntnis der Kohle von Svalbard. 1928. 1(r. 5,50 HOEL, A. und A. K. ORVIN, Das Festungsprojil auf Spitzbergen. Karbon-Kreide.
I. Vermessungsresultate. 1937. Kr. 4,00.
FREBOLD, H., Das Festungsprojil auf Spitzbergen. Jura und Kreide. Il. Die Strati- graphie. 1928. Kr. 3,00. .
FREBOLD, H., Oberer Lias und unieres Callovien in Spitzbergen. 1929. Kr. 2,50.
FREBOLD, H., Ammoniten aus dem Valanginien von Spitzbergen. 1929. Kr. 4,00.
HEINTZ, A., Die Downtonischen und Dpvonischen Vertebraten von Spitzbergen.
Il. Acanthaspida. 1929. Kr. 15,00.
HEINTz, A., Die Downtonischen und Devonischen Vertebraten von Spitzbergen.
Ill. Acanthaspida. - Nachtrag. 1929. Kr. 3,00.
HERITSCH, F., Eine Caninia aus dem Karbon des De Geer-Berges. 1929. Kr. 3,50.
ABS, 0., Untersuchungen iiber die Ernåhrung der Bewohner von Barentsburg, Svalbard. 1929. Kr. 5,00.
FREBOLD, H., Untersuchungen iiber die Fauna, die Stratigraphie und Palåo- geographie der Trias Spitzbergens. 1929. Kr. 6,00.
THOR, S., Beitråge zur Kenntnis der invertebraten Fauna von Svalbard. 1930. Kr. 18,00.
FREBOLD, H., Die Altersstellung des Fischhorizontes, des Grippianiveaus und des unteren Saurierhorizontes in Spitzbergen. 1930. Kr. 4,00.
HORN, G., Franz Josef Land. Nat. Hist., Discovery, Expl., and Hunting. 1930. Kr. 5,00.
ORVIN, A. K., Beitråge zur Kenntnis des Oberdevons Ost-Gronlands. HEINTZ, A .•
Oberdevonische Fisehreste aus Ost-Gronland. 1930. Kr. 4,00.
FREBOLD, H., Verbr. und Ausb. des Mesozoikums in Spitzbergen. 1930. Kr. 17,00.
ABS, O., Ober Epidemien von unspezijischen Katarrhen der Luftwege auf Svalbard.
1930. Kr. 2,00.
KlÆR, J., Ctenaspis, a New Genus of Cyathaspidian Fishes. 1930. Kr. 1,00.
TOLMATCHEW, A., Die Gattung Cerastium in der Flora von Spitzbergen. 1930. Kr. 1,00.
DET KONGELIGE INDUSTRI-, HÅNDVERK
OG SKIPSFARTSDEPARTEMENT NORSK POLARINSTITUTT
SKRI FTER
Nr.
97THE DOWNTONIAN AND DEVONIAN VERTEBRATES OF SPITSBERGEN. IX
MORPHOLOGIC AND SYSTEMATIC STUDIES OF THE SPITSBERGEN CEPHALASPIDS
RESULTS OF TH. VOGT'S EXPEDITION 1928
AND THE ENGLlSH-NORWEGIAN-SWEDISH EXPEDITION 1939 BY
GUSTAV WANGSJO
WITH 108 FIGURES IN THE TEXT AND 118 PLATES
A. TEXT
OSLO
I KOMMISJON HOS JACOB DYBWAD
1952
Con ten t s .
Page
Prefaee . . . . . . . 7
Introduetion . . . . 9
M aterial and methods . . . . . . .. 1 5 List of loealities . . . ... ... . . ... . . ... . . 1 8 General anatomieal remarks . . . . . . . . . . .. 26
External features of the eephalie shield . . . ... ... . . ... . . . 26
Exoskeleton of the cephalie shield ..... ..... . . ... . ...... . . ..... 40
The endoskeleton . . . . . . . . . . 5 2 The endocranium . . . .. 57
The ethmoidal region . . . . . . .. 5 8 The orbito-temporal region . .... . . ... ... . ..... . ... .. .... ..... 62
The otie region . . . .... . ... ... ..... . . .... .... ... .. . .. . . ... . 7 9 The occipital region . . . ... . ..... ..... . . .... . . .. ... . . ... ... . 86
The inter-zonal endos keleton . . . . .. ... 1 0 3 The viseeraI endoskeleton .. . . ...... . . .... . . ... . . 1 1 6 The zonal endoskeleton or the endoske Jetal s houlder-girdle . . . ... . . . 1 70 The proneph ros eomponent ... . ... ...... ... ... . . ........ . . 1 84 The sensor y line s ystem . . . . .. 1 84 The sensor y fields .. . . ... ... . . ... . ... . . 1 92 The eranial nerves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 9 8 The vessels in t he cephalie shield . . . . . . . . . . . . . . . 2 1 0 The seale-eovered trunk division . . . . ..... . . . ... . . ... . ....... ... . . ... . 2 3 0 Mode o f living . . . . 2 3 5 S ystematie des eription . . . . . .. . . ... ........ . . 237
Famil y Cephalaspididae . . . ... . . ... . ... . ... . . ..... . . . ... . . 237
Subfamil y Cephalaspidinae . . . . . . . . . . . . . . . . . . . . . .. 243
Genus Cephalaspis Agassiz . ... ... . .......... .. .. . . .. ...... 243
A. Spe eies from t he Bay series . . . . . . . . . . . . .. 2 5 2 1 . Cpphalaspis aarh usi n. s p . .... ....... .... . . .. .. ... ... 252
2. cradleyensis Stensio ... . . ....... ... ......... 255
3. (lclllninata n. sp . . . . . . . . . . . . .. 2 5 8 4. eurhynch us n. sp. . . ... . . .. ... . .... . . .. 262
5. tØyni n. sp . . . . .... .... . ....... . . . ... ... . . . .... 265
6. hrouRh i n. sp. . . . ... . . ..... . . . . . . . .. 268
7. deltoides n. sp. ... . ... .... ... 27 1 8. divaricata n. sp . . ..... . .... .... . . ..... ....... 274
9. orcas n. sp . . .. . . . . . . . . 278
1 0. heintzi Stensi i.i . . . . . . .. 28 1 11. pYRmaea n. sp . . ... ..... . . ... . . ... 2 8 5 1 2. dissim ulata n. sp. . . . . . . . .. 288
1 3. hoeli Stensio . . . ... . . ... . ... . . .... . . 292
14. exilis n. sp . .. .... . . . .... . ....... ... . . ....... . . . 296
1 5. re/usa n. sp. . . . . . . .. 299
1 6, cukeraspidoides Stensio . . . . . . . . . 3 02 17. hyperhoreus n. sp . . . ... . ...... . . ......... ... . . 305
-4- Page
1 8 . Cephalaspis exee?lens n .. �p . . . . . .. . . . ... . . ... . . . 308
1 9 . vogtl Stens lO . . . ..... . . 3 1 4 20 . powriei Lan k. v.polar·s Il. v.::r. . ... . . ... . . . 3 1 7 2 1 . eurynotusn.sp . ... 320
2 2 . reetieornis n . sp . . . 3 2 3 2 3 . platyeephalus n . sp . . . . .. 3 27 24. verrueulosa n. sp . . ... 3 3 0 2 5 . sinuata n . s p . . . . . . .... . . ... . . ... . . 3 3 4 26. tenuieornis n . sp . . . . . . . .. 3 3 8 2 7 . aretieus Stensio .. . . . .. . . .... . . 342
28. erofti n . sp. . .. . . .. 3 44 2 9 . signata n. s p . . . . ... . ... . . ... . . .... . . 3 4 7 3 0 . eorystis n . sp . ...... . . ... . . ... . . 3 5 2 3 1 . hastata n . sp . . . .... . . .... . . 3 5 6 3 2 . ibex n. sp. . . . . 3 60 3 3 . doryphorus n . s p . . . . . ... . . ... . . ... . . . ... . . . ... , 3 64 3 4 . metopias n . sp. . . . . .. 3 6 6 3 5 . pinnifera n. sp . . ... 3 7 0 3 6 . ? pedata n. s p . . ... . ... . . . . . . ..... . . ... . . 3 7 5 B . Spe eies from t he Wood Ba y series . . . ... ... ... . . ... . ... . . , 3 7 8 37 . Cephalaspis jarviki n. s p . . ... . ... . ....... . ........ . . ... . . . 3 7 8 3 8 . isaehseni Stensio . ... , 3 82 3 9 . eurta n. s p ....... . . .... ... . . . .... . . 3 8 2 40 . fraetieornis n. sp. . ... 3 8 5 4 1. brevieornis Sten si o ? . . .. . . .. 3 8 8 42. produeta n. sp. . . . . . . .. 3 90 43 . oblonga Stensi o . . . ... . . ... . . ... . . ... . . 3 9 3 44. moy-thomasi n. sp . . ... , 3 9 6 4 5 . semicireularis n. s p . . . ... ...... . . ..... . ...... . ... . 3 9 9 46. me.noid�s n . s P: .. ' ..... . . ... . . ..... . . 402
47. latleorms Stens lO . . . . ... ..... ... . . 405
48. earoli n. sp . . . . .. 408
49. gigas n . sp . ... . ........ . . ... 4 1 1 5 0 . lanternaria n . sp . . . . 4 1 6 Spe eies previousl y known from Spitsbergen, but not found in t he present material . . . .. 420
Cephalaspis specimens indeterminable as to species . . . ... . .... . 423
Genus Seeuriaspis Stensio . .. . . .. . ... . . ... . . ... . ... . . . 427
l. Seeuriaspis staxrudi (Stensio) . . . .. 429
2 . quadrata n. sp . . . . . . . . .. 4 3 3 sp. . . . .. ... 4 3 5 Genus Tegaspis n. gen . . . . 437
Tegaspis kolleri (Stens io) . . . . ... ... . . . ... . . ... . . 4 3 8 Genus Eetinaspis n. gen . . . 442
Eetinaspis heintzi n. sp . . ... . . ... . ... . . 443
Genus Benneviaspis Stensio ...... . . ... . ... . . ... . . ... . . 446
A . Spe eies from the Red B a y series . . ..... . . ... . . . ... ... . ... , 448
l. Benneviaspis longieornis Wangsjo . ..... . . , 448
2 . holtedahli Stensio . . . . . . .. 450
3 . p latessa n . sp . . ... . . ... . . ... . . .... 454
sp. 1 .. . . . ......... .... . ... . . ... . . .. 456
B . Spe eies from the Wood Bay series . . ... . . ... . . 4 5 8 4 . Benneviaspis IOvgreeni n. s p . . . . . . . . . . . 4 5 8 5 . grandis n. s p . . .. . . ..... . . ... ... . . . ...... , 4 6 0 6. maxima n. sp. ..... . . ... . . ... ....... . . 462
sp. 2 ... 466
Genus Hoelaspis StensiO . . . . ...... . . ... . . ... . . , 467 Hoelaspis angulata StensiO .. .. ... . ... . . ........... . ...... . . . , 4 69
- 5- Page
Genus Boreaspis Stensio . .. . . ..... . . ... . . ... . . 472 1. Boreaspis robusta n. sp . . . . ... . . ... . . 476 2. puella n. sp. . . . . .. 48 1 3 . costata n . s p . . . . ... . . 483 4. intermedia n . sp . . . . . .. 486 5. batoides n. sp. . . . . . ... 489 6. macrorhynchus n . sp . . . . . 49 1 7. rostrata Stensio . . . .. . . .. 494 8. spinicornis n . sp . . . . .. 497 9. triangularis n . sp. . . ... . . . ... . .... . . 50 l
1 0 . circinus n. sp . . . . . .. 504 Il. curtirostris n. sp. . . . .. 506 12. gracilis n. sp . . . . .. .. . . ..... . . ... ... . . 5 1 0 1 3. ceratops n. sp . . ... .... . ... 5 1 3 sp . . ... . . . . . 5 1 6 Genus Kiaeraspis Stensio ... ... ... . .. .. . .. . 5 1 7 5 1 9 Kiaeraspis allch enaspidoides Stensio .
Genus Axinaspis n. gen . . . .. . . .. . . .. . . .. . . . Axinaspis wh itei n. sp . .
Genus Acrotomaspis n. gen . .. . ... . . ... .. . 1 . Acrotomaspis instabilis n. sp .. ... .
sp . 1 . ... .
2. trinodis n. sp. .
sp . 2 . ... .
Genus Nectaspis n. gen. . . . . . . . . . . . ..... . .
1 . N ectaspis peltata n. sp . . ..... . .
2. llreolatll n . sp .
3 . del/ei n. s p . . . ... ... .. . ... ... . . . .... ... . Remarks on other Osteostraci ... .... ... ... ... . . Some comments upon other agnathous vertebrate groups in relation to the Oste-
5 2 1 523 526 529 5 3 3 5 3 3 5 3 6 5 3 7 5 3 9 542 547 550
ostraci . . . 5 5 9 Stratigraphical r emarks ... .... . . ... . . ... . . . ... 5 6 8
Summar y 5 8 6
Literature cited . . . . . ... . . ... . . ... . . .. 5 9 4
place-names of Svalbard are generally given in the recognized Norwegian forms. However, in this publi
cation the English forms appear because the author had used them and because wc, owing to various circllmstance" had no opportllnity to examine the paper before we rcceived the page proofs.
NORSK POLARINSTITUTT
Preface.
During the geological investigations in Spitsbergen carried out by the Norwegian expeditions in the years of 1906- 1 925 inter alia a large material of Devonian vertebrates was brought together. Of this material the Cephalaspids have been described by Stensio in 1927, whereas some other groups have been treated by Kiær and Heintz (in 1929, 1930, 1932, 1935 and 1937).
Since 1925 large new collcctions of fossil vertebrates have been made in the Devonian of Spitsbergen by Th. Vogt's expedition in 1928 (see Vogt 1930) and by a special palaeontological English-Norwegian
Swedish expedition in 1939, here briefly called the ENS expedition.
The present work is devoted to the Cephalaspids in the said new co llections.
The greater and most important part of this new material of Cephalaspids was brought home by the ENS expedition. The planning and realization of this expedition was mainly the work of Professor E. Stensio, Stockholm, under whose leadership the expedition was car
ried out. Otherwise the expedition was the result of a close cooperation between the British Museum of Naturai History in London, the Palaeonto
logical Museum in Oslo and the Palaeozoological Department of the Swedish Museum of Natural History in Stockholm, and as leaders from the English and Norwegian sides took part Dr. E. I. White, London, and Professor A. Heintz, Oslo. An account of the expedition and of the geological results, obtained during it, has been published by FØyn and Heintz (1943). The expedition visited most of the Devonian areas both in the Ice Fiord district and at the firths of the north coast. Parti
cularly the Wood Bay series yielded much material, and its vertebrate fauna appeared to be surprisingly rich both in Cephalaspids and other lower vertebrates. A large and important material of lower vertebrates was also collected in the Red Bay series. In all more than 600 specimens of Cephalaspids were brought back by the expedition.
The material of Cephalaspids brought home by Th . Vogt's expedi
tion in 1928 mostly comes from the Red Bay series. It includes 132 specimens, severai of which are excellently preserved and very valuable from an anatomical point of view.
Besides the collections just mentioned some previously undescribed
- 8-
specimens from Th. Vogt's expedition in 1925 (see Vogt 1 926) and a single specimen of the Lewin collection in the Palaeozoological Depart
ment of the Swedish Museum of Natural History in Stockholm have also been dealt with in the present work.
The writer has had the opportun it y of going through all the speci
mens of Cephalaspids described by Stensio and some of these specimens are als o treated and discussed in the present work.
The material of Cephalaspids collected by the Norwegian expedi
tions in 1906- 1 928 all is in the possession of the Palaeontological Museum of Oslo. It will be referred to below under the numbers of that museum. The material of Cephalaspids brought together by the ENS expedition belongs to the British Museum (N. H.) in London, the Palaeontological Museum in Oslo and the Palaeozoological Depart
ment of the Swedish Museum of Naturai History in Stockholm, but as it has not yet been divided among these museums, it will here be dealt with as a unit so that the individual specimcns are referred to as ENS nos. 1-616, respectively.
In view of the circumstance that StenslO's paper is chiefly a treatise of the anatomy of the Cephalaspids, the present work was originally planned as a taxonomic research of the new material of Spitsbergen Cephalaspids collected since 1925. D uring the course of the investiga
tions it appeared, however, that the material also offers much of anatomical interest. Under such conditions it was necessarry to treat here some points of the general morphology, and hence the present work also includes an anatomic part. This part does not contain a complete account of the anatomy, but intends chiefly to point out certain new facts and to describe such structures which are of general interest and lead to new interpretations of certain anatomical conditions.
In presenting the results of my investigations I wish first to express my great obligation to Professor E. Stensio, Stockholm, Dr. E. 1. White, London, and Professor A. Heintz, Oslo, for entrusting to me this valuable material. I also acknowledge here my debt of gratitude to the late Professor G. Save-Soderbergh for excellent working facilities at the Palaeontological Institute of Uppsala. To Dr. Elsa Warburg and Pro
fessor P. Thorslund, the succeding heads of the institute, I also wish to express my grateful thanks. For their efforts of bringing this paper into press I tender my sincere thanks to Professor A. Heintz, Oslo, and to Professor H. U. Sverdrup, Director of Norsk Polarinstitutt, Oslo.
The retouching of the photographs and the final drawings of the figures have been made by Messrs . E. Ståhl and A. Nilsson, Uppsala ; a few photographs have been retouched by Mr. S. Ekblom, Stockholm.
The revision of the English manuscript has been made by Professor O. Zdansky, Uppsala. To these collaborators and to others who in any way have facilitated my work I here wish to express my cordial thanks .
Introduction.
The magnificent monograph by Stensib (1927) on the Cephalaspids from Spitsbergen constitutes a milestone in the history of investigations into the Osteostraci and likewise all other sections of fossil agnathous vertebrates, and it forms the natural and, in faet, only eoneeivable basis for all subsequent works on this group.
Through the researches of Stensib our knowledge of the most primitive fossil vertebrates was immediately enormously enlarged. The inner anatomieal strueture of the eephalie shield in the Osteostraei was elucidated in detail, and it was thereby made wholly evident that the group belongs to the agnathous and monorhinous vertebrates. The relation of the Osteostraci to the other groups of the Ostraeoderms and to the reeent Cyclostomes was diseussed. The group was proved to be most nearly related to the Anaspida, and it was thought to be more closely akin to one of the two re cent eyclostomous groups, viz.
the Petromyzonts, than these between themselves. A later paper by Stensib (1932), on the Cephalaspids of Great Britain, supplements this work in dealing particularly with the trunk behind the eephalie shield and the minute strueture of the exoskeleton.
A valuable abstraet of the results of Stensib on the eephalie anatomy of the Cephala:�pids is given in a paper by StensiO & Holm
gren ( 1936) whieh also eontains many comparisons with the modern Cyclostomes.
Stensib's conclusions with regard to the Osteostraci as agnathous vertebrates have been generally accepted but in reference to the con
tents of the group Ostracoderms and to the interrelationship between its different sub-groups and between these and the two recent cyc1osto
mous groups, the opinions of later authors are mueh at varianee.
Following upon the works of Stensib our knowledge of the Osteostraei has been inereased by the researches of severai authors.
The Osteostraci faun as of Saaremaa (Oesel ; cf. also Luha 1940;
Bblau 1949; Robertson 195 1 a), most interesting in view of being the oldest well preserved vertebrate faunas known dating from the Lower Ludlow, have been the subject of extensive researches. A very large material was brought home by Patten, and he has briefly described (Patten 1 93 1 ) two new speeies of Tremataspis (T. milleri and T . mam-
-10-
mil/ata) and "Didymaspis" pustulata as weU as a new genus Dart
muthia, with the speeies D. gemmijera, considered to represent a new family connecting the Cephalaspids with the Tremataspids . A new restoration of the lower side of the shield in Tremataspis, showing the disposition of the plates of the oralo-branchial fenestra, was als o given by Patten ( 1 9 3 2) .
After the death o f Patten i n 1 9 32 his material has been worked up by Robertson in a long series of papers . The genus Dartmuthia was more fully described and figured (Robertson 1 9 3 5 a), a new genus, Oesel
asp is, was founded (Robertson 1 9 3 5b) on "Didymaspis" pustulata and a detailed description was given of the speeies . In the same year he gave a preliminary classification of the Osteostraci (Robertson 1 9 3 5c) as follows :
"Family Cephalaspidae Agassiz 1 8 44
Sub-family Cephalaspinae StensiO 1 9 32 Sub-family Kiaeraspinae Stensio 1 9 32 Family Tremataspidae Woodward 1 8 9 1 Family Dartmuthiidae Patten 1 9 3 1 Family Oeselaspidae Robertson 1 9 3 5 ."
Robertson ( 1 9 3 8 a) has furthermore dealt with the Tremataspids.
He gives i . a. a new restoration of the plates of the oralo-branchial fenestra, and a description of the courses of the sensory lines and of some details of the inner anatomy ; seven speeies of the genus are described (four of them as new speeies, viz. T. panderi, T. patteni, T. rohoni and T. scalaris; cf. Luha 1 940 ; Denison 1 947).
Two new genera have been proposed by Robertson (l9 3 8b) : Saaremaaspis, supposedly with short cornua and with one pair of short lateral sensory fields, is assumed to belong to the sub-family "Kiaer
aspinae"; type speeies (and only speeies) is Tremataspis mickwitzi of Rohon ( 1 8 92) . Rotsikilliaspis with the new speeies R. obrutchevi is apparently related to Dartmuthia.
In a later paper (Robertson 1 939a) he redescribes the speeies Cephalaspis schrenkii, erected by Pander as early as in 1 8 56, and pro
poses the new genus Witaaspis for its reception.
A supposed representative of the genus Cephalaspis from Sa are
maa is described (Robertson 1 9 3 9b) as C. oeselensis in apaper which also contains a survey of the Osteostraci from Saaremaa, described till then . Rotsikiillaspis is now assigned to the family Dartmuthiidae. A second speeies of Witaaspis (W. patteni) is described (Robertson 1940a) . A description of the sensory lines in Thyestes verrucosus is given in the same year (Roberts on 1 940b), and these lines are found in some respects to agree with those of Tremataspis.
In 1 945 Robertson ( 1 945) gives a redescription of the Saaremaa speeies placed by him in the family "Cephalaspidae", viz. Thyestes
1 1 -
verrucosus, Witaaspis schrenkii, W. patteni, Saaremaaspis mickwitzi and Cephalaspis oeselensis. He also discusses all the genera proposed in this family, and the characteristics which are thought to denote groups of family rank, and, finally, gives a classification list of all the genera in Osteostraci. His list, down to sub-families, runs as follows :
"Order Osteostraci Lankester Family Cephalaspidae Agassiz
Sub-family Cephalaspinae Stensia Sub-family Hemicyclaspinae Heintz Sub-family Kiaeraspinae Stensia Family Tremataspidae Woodward Family Dartmuthiidae Patten Family Oeselaspidae Robertson Family Didymaspidae n. fam."
It is a development of his list in 1 9 35, and it is interesting to note that the order is not subdivided into groups of super-family rank (the Trernataspids are thus not placed in a group distinet from the other families, cf. Berg 1 9 3 7 ; 1 940 ; Heintz 1 9 39) and that the genus Didymaspis is placed in a family of its own.
The min ute structure of the exoskeleton of Tremataspis and other Silurian Osteostraci has been studied by Gross ( 1 9 3 5 ; 1 947), Wangsjo ( 1 944), Bolau ( 1 95 1 ) , and particularly by Denison ( 1 947 ; 1 95 1 b) ; the latter, and BOlau, have observed the relations of the sensory lines to the mucous canals, and have both put forward a new interpretation of this canal system ; they have also made some very interesting observations on the growth of the exoskeleton. Denison's interpretation of the mucous canal system has rightly been critizised by Robertson in a recent paper (Robertson 1 9 5 0) , in which he als o enters upon a discussion of the specific criteria used in the Cephalaspids and more especially in the genus Tremataspis.
Four new Cephalaspis species (C . canadensis, C . acadica from the supposed Eodevonian, and C. patteni, C. rosamundae from the Neodevonian) frol? Canada have been described by Robertson ( 1 936;
1 9 3 7 ; 1 94 1 ) .
The first Cephalaspid, found in U. S.A. , has been described by Bryant ( 1 9 3 3) as Cephalaspis wyomingensis. Some very small bone frag
ments (Ohioaspis) from the Mesodevonian of Ohio have been referred to Osteostraci on account of their minute structure (Wells 1 944) .
In Germany som badly preserved remains are described as Cephal
asp is diensti, in addition to two indeterminable Cephalaspid fragments, all from the Upper Eodevonian (Gross 1 9 3 3 a ; 1 9 3 3 b ; 1 9 37) .
A partly exceptionally weU preserved specimen, holotype for the new speeies Cephalaspis kozlowskii, has been thoroughly studied by
Zych ( 1 9 3 7) ; some of the superficial vascular canals of the dorsal side of the shoulder-girdle are described and interpreted as being connected to the vascular canal system of the pectoral fin, and the n. glossopharyngeus is said to have run in a canal behind the labyrinth cavity and not to have pierced this cavity.
A new Cephalaspis species (C . jack i) is described from England by White ( 1 9 35b) and a new Benneviaspis species (B.longicornis) from Spitsbergen by Wangsjo ( 1 9 3 7) .
A badly preserved specimen and some isolated scales from the Downtonian of Scotland are described as a new genus and species, Hemiteleaspis heintzi, by Westoll ( 1 945), who in this connection also enters upon severaI questions of general interest with regard to the anatomy and growth of the cephalic shield and the evolution of the Osteostraci.
Lehman ( 1 937) has described undeterminable fragments of Oste
ostraci from the Upper Ludlow of Scania (Sweden), and some fragments Ci. a. of Darthmuthia) from Gotland are mentioned by Spjeldnæs ( 1 950) . I n a most important paper Heintz ( 1 9 3 9) has given a very detailed account of two Cephalaspids from the Downtonian of Norway, viz . Aceraspis robusta and HirelIa ("Micraspis") gracilis, first described by Kiær ( 1 9 1 1 ) . He gives i. a. interesting informations on the scle
rotic ossifications and on the ventraI visceral exoskeleton, and accor
ding to him, the position and the shape of the mouth opening is quite different in these two closely related forms. Both speeies have the anterior portion of the dorsal fin-fold developed as a high and thin anterior dorsal fin or fin-like crest (it is, however, interpreted as being forrned in essentially the same way as the dorsal crest in e. g. Hemi
cyclaspis). Very peculiar is the structure of the caudal fin with a horizontal membrane on its antero-ventral part (this membrane is shown to occur als o in Hemicyclaspis, A teleaspis and Cephalaspis, and is thought to be characteristic of the caudal fin of the Cephalaspids in general). A teleaspis tesselata is also redescribed. This genus, and A ceraspis, HirelIa and Hemicyclaspis are placed in a subfamily of their own, "Hemicyclaspinae" . The classification of the order Oste- ostraci according to Heintz is this : .
"Order Osteostraci
Sub-order Cephalaspida Fam. Cephalaspidae
Sub-Fam. Hemicyclaspinae Sub-Fam. Cephalaspinae Fam. Kiaeraspidae
Sub-order Tremataspida."
- 1 3 -
Recently Denison ( 1 9S 1 a), in a paper on the evolution and c1assifi
cation of the Osteostraci has put forward a new c1assification of the order, taking into account all the known genera, but with particular reference to those from the Lower Ludlow of Saaremaa. Witaaspis patteni is synonymized with W . schrenkii and Rotsikiillaspis obrutchevi with Saaremaaspis mickwitzi, Cephalaspis oeselensis is referred to a new genus, "Procephalaspis", and Cephalaspis woodwardi to another new genus, "Stensiopelta". The c1assification of Dension is as follows :
"Order Osteostraci Family Tremataspidae
Subfamily Tremataspinae
" Dartmuthiinae
" Oese1aspinae
" Didymaspinae Family Sc1erodontidae
" Ateleaspidae
Family Cephalaspidae
(Tremataspis)
(Dartmuthia, Saaremaaspis) (Oeselaspis)
(Didymaspis) (Sclerodus)
(Hemicyclaspis, Hem ite leasp is, Micraspis, A ceraspis,
A teleaspis, Witaaspis)
Subfamily Cephalaspinae (Thyestes, Procephalaspis, Cephalaspis)
" Benneviaspinae (Securiaspis, Benneviaspis, Hoelaspis, ? Boreaspis,
Family Kiaeraspidae
Stensiopelta) (Kiaeraspis) ."
General views as to the position of the group Osteostraci in the vertebrate system are expressed by Goodrich, de Beer and Watson (Goodrich 1 9 3 1 , de Beer 1 9 3 1 ) , and Sewertzoff ( 1 9 3 1 ) . Goodrich and de Beer i. a. lay stress upon the many points of agreement in the structure of the two recent cyc1ostomous groups and object to the supposition (advanced by Stensio 1 927) of a polyphyletic origin for them (similar views are expressed by Sewertzoff 1931). This opinion is also held by White ( 1 9 3 S a), who places the Osteostraci as a c1ass and order of its own among the Agnatha, in rank with the Heterostraci (exc1usive of the Coelolepids), Anaspida and Cyc1ostomata, and by Watson ( 1 9 37), who applies the same divisions.
The c1assification of Berg ( 1 9 3 7 ; 1 940) is somewhat different and is in agreement with that of Stensio ( 1 927) in so far as he separates the two recent cyc1ostomous groups ; he divides the Agnatha into four c1asses : Cephalaspides (Osteostraci), Petromyzones, Pteraspides (Heter
ostraci) and Myxini. The Cephalaspides are made to contain the sub
c1ass Cephalaspides (with the orders Cephalaspidiformes and Tremat
aspidiformes) and the subc1ass ? Birkeniae (Anaspida).
A similar conception of the larger groups within the Agnatha is found in a paper by Gross ( 1 9 3 9), partly expressed in an earlier paper (Gross 1 9 3 3c) .
Moy-Thomas ( 1 9 3 9) classifies the Agnatha in the following way :
"Sub-class 1 . Ostracodermi
Ord. 1 . Heterostraci = Pteraspida Ord. 2 . Coelolepida
Ord. 3 . Osteostraci = Cephalaspida Ord. 4 . Anaspida
Sub-class 2 . Cyclostomi."
Only the orders Osteostraci and Anaspida are thought to be closely related to one another ; the Coelolepids are hesitatingly placed in the Agnatha ; the possibility that the modem Cyclostomes may be the descendents from a cephalaspid- or anaspid-like ancestor is appre
ciatively discussed.
Heintz has also dealt with these questions ; he adopts (Kiær &
Heintz 1 9 3 5 ) in some measure the classification of Stensio ( 1 927), but leaves open the question as to the relations of the recent Cyclostomes to the fossil groups. The divisions of Zych ( 1 9 3 7) are in accordance with those of Stensio.
WestoIl ( 1 945) discusses i. a. the possibility that some Coelolepids may be related to the Osteostraci (even the p ossibility that they may be "larval" Osteostraci) , others to the Heterostraci, and yet others to the Anaspida. The evolution of the group Agnatha is considered by Obruchev ( 1 945) in conjunction with a discussion of the development of the exoskeleton . Contrary to the views of Stensio he assurnes a progressive evolution from forms with small exoskeletal units towards forms with large and compound plates (cf. also "the lepidomorial theory" of StensiO & 0rvig, see Ørvig 1 95 1 , pp. 366-368). The Thelodonti are regarded as the basal agnathous group from which the Heterostraci, the Osteostraci, the Anaspida and the recent Cyclostomata have evolved.
The systematic position of the group Heterostraci, as of interest in this connection, has lately been examined als o by Balabai ( 1 948).
Morphological questions connected with the Cephal aspids are dealt with by Allis ( 1 93 1 a, mouth-opening and visceral skeieton ; 1 93 1 b, naso-hypophyseal canal), Bohlin ( 1 94 1 ; sensory fields) and Holmgren ( 1 942 ; sensory line system), and furthermore discussed in a greater or lesser degree in connection with investigations into the anatomy or embryology of Petromyzon by Damas ( 1 943), J ohnels (1948 ; 1 95 0) . and Lindstrom ( 1 949).
Material an d met hod s .
The cephalaspid material from Spitsbergen, treated in this paper, is on the whole of the same type as that described by Stensio ( 1 9 27) ; the fossils thus consist almost exc1usively of cephalic shields or fragments of such shields. On one occasion only parts of the trunk have been found associated with the cephalic shield (a specimen of Cephalaspis pinnijera). Parts or fragments of the detached trunk are present in two cases.
The types of the vertebrate-bearing rocks from the Spitsbergen Old Red, as far as of interest in this connection, have been described by Stensio ( 1 927, p. 1 8), Heintz ( I 929a, p. 2 1 ) and Kiær & Heintz ( 1 9 3 5 , pp. 1 7- 1 8), and I can therefore in the main refer to these authors .
The rocks are different kinds of sandstone, which always are ca1ciferous ; in some places the rock has the character of a lime-sand
stone. Of ten, especially in Mt Ben Nevis, the rock is conglomeratic, the conglomerate is intra-formational, and the small nodules consist of mud-stone fragments (cf. Heintz 1 929a, p. 2 1 ). Concretion-like nodules, containing fossils, occur in a few places : Fraenkel Ridge, in the "Psammosteus" layer, Mt Ben Nevis, in the Vogti layer and on Mt Pteraspis (cf. Kiær & Heintz 1 9 3 5 , p. 1 7). 1
As to the state of preservation of the fossils in different kinds of
l The result of analyses of the lime-con tent of some sandstone types from Spits
bergen is shown below (the calcite was dissolved with acetic acid (4-n), in sample 4c with 5% and 4d with 1 0% hydrochloric acid; the weight of each samp1e was 20 gl:
1. Red B ay series. Fraenkel Ridge, P rimaeva layer . ... ... .... 45.95% CaCO::
2 . Anglaspis l ayer . . . . 2 8 . 1 5 % 3. Mt Ben Nevis, Benneviaspis layer . . . 3 3 .4 % 4a. A.ndree Glacier, S. half, moraine ... .. 64.5 %
�. . ... . ... .. M .9%
4c. . .... ... 68 .45%
4d. . ... . ... 45.5 %
5. Mt Pteraspis ... . . ... . . . .. .. . .... . 3 9 .55%
6. Wood B ay series. Mt Sigurd, slope towards the Hoffnung Gl.
a) "red layers about 130 m" ... . ... 40.0 % 7 . b ) layer with Boreaspis ceratops . . . ...... . 42.65%
8 . Mt Kronprinz, opposite the Stiørdalen Valley,
grey sandstone . . . . . . . . . . . 311 .5 % 9. Mt Lyktan, S. E. slope .. . ... . . . ... . .. 27.0 %
(Cont. overleaf)
- 16 -
rocks, we can, in addition to what has been said by Stensia ( 1 927) and Kiær & Heintz ( 1 935), state that in some places in the Anglaspis layer on the Fraenkel Ridge the cephalic shields (preserved in a dark grey sandstone) are exceptionally well preserved, the inner parts, including the endoskeletal cavities and canals being filled with calcite, which makes the preparation comparatively easy. The shields from the Pri
maeva layer (in a reddish sandstone) are rather well preserved but the bone-tissue seems in many cases to have been subjected to some chemical alterations so that they will not readily or not at all stain with alizarin ; the same applies to some shields from the lowermost part of the Wood Bay series on Mt Sigurd. Those shields occurring in a grey sandstone in the Wood Bay series are generally much better preserved than those embedded in the usual red or red-brown sandstone. The fossils from the light grey, coarse sandstone in Mt Borgen (Wood Bay series), being well preserved with regard to their external shape, have, however, the inner structures destroyed to a varying degree.
In general it can be said that the exoskeleton is badly preserved and does not show any finer details . The endoskeleton is of ten weU preserved, and more of ten so in the specimens from the Red Bay series than in those from the Wood Bay series. The inner parts of the shields from the Wood Bay series are usually not weU or not at all preserved, and this is very probably primarily due to unsuitable conditions during and after fossilization in the sandstones from this series, and possibly the bad state of preservation is to a certain degree caused by a feebler development of the endoskeletal bone-Iayers (cf. , however, Stensia 1 927, pp . 3 1 -3 2 ; 1 9 32, pp. 1 2- 1 3). The state of preservation varies in some species according to the type of rock in which the different speci
mens are embedded. We find e. g. that a specimen of Cephalaspis lati
carnis from a grey-green sands tone has at least the perichondrial cana]
layers very well developed while the endoskeleton on the whole in other specimens of the same species, but occurring in the usual red sands tone of the same series, is badly preserved. In most of the specimens of Nectaspis arealala the endoskeletal bone-Iayers are more or less deli
cate or even absent but in two specimens from one locality on Mt Lyk
tan they are well and strongly developed (this applies also to two speci
mens of Bareaspis rabusta from the same locality) .
lOa. Wood Bay series. Mt Lyktan, S. E. Slope, sandstone with Nect- 10b.
Il.
12.
13.
14.
J 5.
16.
aspis arealata and Bareaspis robusta, holotypes 37. 6 % CaCO�
ditto . ... . . ........ . . ......... ..... . . . ... 38. 0 5%
Mt Lyktan, Fiskedalen Valley ... . . .. 3 3. 12%
Mt Borgen, N. part . .................... . . . 13. 15%
Mt Errol White, "fossiliferous Iayer ab. 125 m" 34. 3 % StjØrdalen Valley, S. side . ... . . . ... ..... . . .. 20. 6 % , W. part . .... . . .. 23. 7 % Mt Prismefjell, W. sIope, about 20 0 m . . . 21. 2 %
- 1 7 -
Of ten the shape of the fossil shields has been affected by pressure of the rocks and they are thus more or less distorted. This is most of ten the case with shields from the Stjørdalen division of the Wood Bay series (see e. g. Nectaspis del/ei, p. 5 47).
The fossils detach themselves from the embedding rock in such a way that the splitting plane lies either within the exoskeleton through the lower division of the midd le layer or just beneath the exoskeleton in the zone of the subcutaneous canal plexus ; an outer or peripheral part of the fossil thus almost invariably remains on the counterpart.
The preparation of the fossils was first carried out with the help of chisels, and then, under a low-powered binocular magnifier, with a dental mallet. The finer preparation was carried out by fine needies under a binocular microscope of the Greenough type, usually with a magnification of 25-40 times. During this finer preparation the fossils most of ten were soaked with a1cohol, xylol, oil of aniseed, or coated with glycerine, and in such cases a strong illumination was used (as a Leitz "Monla"-lamp or a Reichert pointolit lamp) . In some cases it was found very useful and practical to cut parts of the fossils, in which the deep lying canals or cavities were to be followed, in smaller or lar
ger pieces by means of a pair of sharp pincers. The fossils could thus most of ten be cut as desired and the required canals exposed ; if neces
sary the canals or cavities in these pieces were c1eaned out with the dental mallet or with needies. After studying them in this way the fos
sils were "mended" by gluing together the pieces carefully. For photo
graphing the fossils were of ten immersed in one of the fluids mentioned (or in a few cases in thick canada balsam) and lighted up with the aid of, usually two, strong arc-Iamps. In a few cases the fossils were coated with ammonium chloride, and a soft illumination was used (cf. pls. 2 7 : 2 ; 3 9 : 3). Extreme1y useful i n many cases was the staining of the bone
tissue with alizarin (us ing a saturated solution of alizarin in a1cohol) ; the method has been fully described by Stensio ( 1 944, pp. 5-6) ; in the explanations to the plates in this paper it is always remarked when this method has been us ed on the fossils figured.
The measurements given in the systematic descriptions were always taken directly upon the fossils as they are preserved, thus e. g.
small irregularities in the symmetry of the cephalic shields are not disregarded, even if they have possibly originated during the fossili
zation. Distinctly distorted shields are generally not directly mea
sured but the very approximate dimensions of the restored shields are given. As in most cases it is impossible to say if the fossils have under
gone some slight postmortal distortions or not, it is of course evident, that the figures referring to measurements must be used very cauti
ously, and cannot, in general, be used for more elaborate statistical ca1culations.
2
The thin sections through the exoskeleton for study of its minute structure were made in the ordinary way ; it was, however, in many in
stances found useful first to embed the samples in a transparent plastic (methyl-metacrylate), in the main following the procedure described by Randall & Menzies ( 1 94 1 ).
The grinding method for obtaining serial sections has not been employed.
All the photographs used for the plates or text-figures in this paper have been retouched.
Li st of localities.
(See the maps, figs. 1 -3 ; the numbers on the maps refer to localities or groups of localities, to be found with corresponding figures in the following list. The maps are compiled from those in the papers of De Geer ( 1 9 1 2 ; 1 9 1 3), Isachsen ( 1 9 1 5), Heintz ( 1 929b), Lid ( 1 929), FØyn & Heintz ( 1 943). Many informations have been obtained from
"The Place-Names of Svalbard" ( 1 942). The statements as to longi
tude and latitude are not at all uniform for the different localities, and are in most cases only approximate.)
Localities at the bays of the North Coast ( l -20).
Localities on the E . side of R e d B a y (Raudfjord ; 1-3).
1 . Fraenkel Ridge (Fraenkelryggen), a narrow ridge from the S. part of Mt Fraenkel towards Red Bay, immediately N. of the Andree Glacier (79� 4 1 ' N . , 1 2� 20'-3 0' E . ) .
O n the labels the stratigraphical horizon only i s indicated, and this refers in many cases to a certain locality or to Ioc ali ties within a rather restricted area ; they can more or less exactly be placed with the aid of the statements by Heintz (in Kiær & Heintz 1 9 3 5 , pp. 1 1 - 1 3) ; as to the localities a) - c), see also HØeg 1 942. p. 1 3 .
a) "Psammosteus lag" (horizon), on the easternmost part of the ridge, about 5 00-550 m. (Cephalaspis corystis, C. sp. no. A 30099) ; b) "Corvaspis lag", "Corvaspis horizon", on the N. side of the ridge, along a brook from the glacier on the W. slope of Mt Fraenkel (C. acuminata, C. dissimulata);
c) "Plante lag" (Plant horizon), as b) but further down (C. crad
leyensis, C. pygmaea);
d) "Primaeva lag", " Primaeva horizon", different localities i n a red sandstone in the middle parts o f the ridge, S. of b) (C. acuminata. C. dissimulata, C. divaricata, C. eurhyncllus, C. heintzi, C. hyperboreus, C.oreas, C. pygmaea, C. silluata.
C. verruculosa, Ectinaspis heintzi);
