Trans. Proc. Palaeont. Soc. Japan, N. S., No. 37, pp. 230-237, April l, 1960

PRESIDENTJAL ADDRESS

STUDIES ON TRILOBITES IN LAST THREE DECADES*

TEIICHI KOBA Y ASHI

Among fossils ancient extinct organ­ in trilobite morphology. In a pre­ isms bear particular importance for liminary report (1933) he pointed out palaeontologists because such fossils the analogy and homology of the are monopolistic objects of their study. trilobitan appendages with those of Trilobites are typical of this category. the crustaceans and arachnoids re­ SHIRAKI'S find of Ordovician trilobites spectively, emphasizing that the trilo­ near Mt. Taipaik (:kSilJ) in Korea bite has only one segment of the pro­ drove me in 1926 to this mountainous podite and the characteristic gill-blades region for fossil hunting. In those on the expodite which are quite days the Trilobita belonged to the different from crustacean setae. It Crustacea and comprised 20 families or took much more time to reconstruct so, but now there are about 150 families the appendages of Trentonian Ceraurus which constitute an independent class p!eurexanthemus out of serial sections of the Arthropoda. It is indeed a of its rolled specimens. His Studies on great advancement. Because I was for­ Trilobite Morpho!ogy, Parts l to 3 were tunately able to participate in this successively putlished in 1939, 42, and progress, I wish to outline the results 51 through which it was determined of this epoch in morphology, taxonomy that trilobites have the appendages of and descriptive work. same pattern as those of the Trilo­ It was in summer, 1932, that Dr. bitoidea and they are closely related STØRMER and I were invited by Prof. to the Chelicerata. As a result the RAYMOND to his home. It was a memo­ taxonomic position of the Trilobita rable evening for me, because it was was promoted r.s belo,-;, about the Wendepunkt in Trilobitology. Phylum Arthropoda Needless to say, the late Prof. RAYMOl"D Subphylum Trilobitomorpha STØRMER, was the well known successor of Prof. 1944 BEECHER in this science, who had Class Trilobitoidea STØRMER, 1959 thoroughly proven the crustacean Class Tri lobi ta W ALCH nature of trilobites in 1920 and deve­ Subphylum Chelicerata loped BEECHER'S tripartation of the Subphylum Pycnogonida

Trilobita. Therefore I visited him at It is interesting to note that the Harvard to discuss the trilobite clas­ crest of Palaeontologia Sinica is a tail sification. of a trilobite called Drepanura which STØRMER At that time Dr. was engaged has long been known among the Chinese

* Received Jan. 19, 1960; read at the by the name of bat-stone (CIIANG, 1921). annua! meeting cif the Society at Sendai, About 250 years ago LYwYo (1698) Jan. 16, 1960. described Trinuclei. The first Linnean

230 Studies on Trilobites zn Last Three Decades 231 species was Entomolithus paradoxus, trends, two of which happened to be 17 45, but it was a composite species, r even opposed. A trilobite group form of which was Agnostus pisiformis developed along the trend of a charac� !Lr:-;NE:), 1757. The term. Trilobites, was ter slowly, but the development was proposed by W ALCH in 1771 and 5 quicker in another group. Thus the genera were distinguished by BRoNGNI­ evo l ut ion of trilobi tes is complicated. ART in 1822. Subsequently trilobites For the natura! classification not only had been classified by DAL MAN, EMMRICH, morphological and ontogenetical evi­ 1\!IrLNE-EowARDS, BuRMEISTER, HAwLE dences, but also specio-temporal distri­ and CoRoA, BARRANDE, SAL TER and bution must be brought into consider­ others in various manners befare ation because the parallelism of the BEECHER proposed his Natura! Classifica­ trilobite evolution among palaeogeogra­ tion of Trilobita in 1897. The last one phic provinces cannot be overlooked. was different from the preceding ones Furthermore it was concluded that in that it was founded on recapitula­ at !east four groups of trilobites had tion theory. already appeared in the early Cambrian From ontogenetical point of view period. Therefore their Pre-Cambrian BEECHER laid special stress on eyes and divergence is pre-palaeontological. The facial sutures. His classification re­ jour palaeontological stocks were the ceived wide acceptance, although its Agnostida, Redlichida (or Mesonacida), validity was questioned by PoMPECKJ Corynexochida and Ptychoparida which immediately, a year after the proposal. formed the four primary orders in my REED also noted that part of blindness classification in 1935. The secondary is the result of aphotic adaptation, orders are later groups which appeared although he agreed that many blind so sporadically that their origin is trilobites are primitive. Later the obscure. Hypoparia were ignored by SwrNNERTON Subsequently in 1936 the invalidity (1915). White PauLSEN reported the of the Proparia was vindicated by the proparian suture in the early larva! discovery of a proparian off-shoot of stage of Peltura scaraboeoides (1923), the Olenidae in the Lower Ordovician RrcrrTER (1932) considered the Proparia of Argentina. In the same year STus­ to be more primitive than the Opistho­ BLEFIELD discussed cephalic sutures in r;aria. great detail and concluded that the In 1935 I point�?d out the polyphyletism proparian condition might be regarded of the Proparia as well as the Hypoparia as arrested development. WHITEHousE by the fact that Cambrian proparians (1936, 39) on the other hand recongniz­ or hypoparians reveal little relationship ed 7 Cambrian stocks of trilobites. In not only among themselves, but also to applying ]AEKEL's terms (1909), he com­ later proparians or hypoparians. There­ bined his Agnostida and Eodiscida into fore I had to conclude that BEECHER's the Miomera and the remaining five three orders are not natura! groups. into the Polymera. Then, REssER (1938) Although the facial suture is one of segregated his Agnostida out of the the most important criteria, the natura! Trilobita inclusive of eodiscids. On classification must be founded on com­ the contrary, I monographed the bination of evolutional characters. Each agnostids (1939) and eodiscids (1944) biocharacter developed in one or more with the result it was concluded that 232 Teiichi KOBAYASHI

the two constitute my Agnostida which of Asia or the Pacific province. This represent the most specialized distinc­ was the reason why I made a special tive order of the Trilobita. study on Cambrian genera and families. After the rejection of the tripartation, Though very tentative, in 1935 I clas­ STØRMER (1948) applied BEECHER's orders sified the Cambrian trilobites into 34 to his classification, beside Protoparia families which were grouped into the which was a homonym of SwrNNERToN's above 4 primary orders in addition to (1915). He took the olenellid anapro­ the Dikelocephalida. taspid for the incipient form, but re­ Lately the interfamily relationship cently WHrTTINGToN (1957) pointed out was examined by HENNINGSMOEN (1951) that the smallest olenellid larvae so far with special reference to the outline known are meraspid cephala, instead of the glabella and its furrows, althou­ of protaspids. BEEcr-rER'S orders were gh the relation of the glabella to the accepted still later in some text-books major cephalic configuration, I think, (MooRE, LALICKER and FISCHER, 1952; would be no less an important criter­ SHROCK and TwENHOFEL, 1953). Natural­ ion. He obtained 12 superfamilies, two­ ly doser studies were made on cephalic thirds of which were derivatives from sutures by many students. RAsETTI the Conocoryphacea. Then, HuPf: (1953, (1952) distinguished 7 types of sutures 55) combined the Eodiscoidae and among early Cambrian trilobites to Agnostoidea into the Miomera and the which two later Cambrian types were other 24 superfamilies into the Poly­ added. More types are known at pre­ mera. In the latest classification elab­ sent, but at the same time it has been orated by HARRrNGToN et al. (1959) the ascertained that the same suture type comprehensive Polymera or Conocory­ occurs in the three polymeric orders. phacean derivatives are divided into About 30 years ago the classification several orders and suborders. In seeing of Cambrian trilobites was so ambigu­ this scheme in Treatise on Invertebrate ous that even specialists arranged them Paleontology I �as rather astonished to in the alphabetical order by generic find that the result agrees with mine names. Especially, little was known of so well in the fundamental frame as intergeneric relationship among those seen below.

Trea tise, 1959. Author, 1935. Agnostida KosA Y ASHr...... Agnostida Redlichida RrcHTER ...... Mesonacida (or Redlichida)

Corynexochida KosA Y ASH r ...... Corynexochida

Ptychopariida SWINNERTON ...... Ptychoparida Ptychopariina RICHTER ...... (Ptychoparida)

Asaphina SAL TEl� ...... Dikelocephalida (from Ptychoparida, 1936) Illaenina ]AANUSSON ...... Proetacea (from Ptychoparida)

Harpina vVHITTINGTON ...... Harpar.ea (ditto.) Trinucleina SwiNNERTON ...... Trinuclacea (ditto. )

Phacopida SALTER ...... (Phacopacea )

Phacopina STRUVE ...... -...... Phacopacea (unknown origin) . . \ Cheiruridae (ditto. ) Che1runna HARRINGTON and LEANZA ...... Encnnun'd ae (d'1tto. ) Studies on Trilobites in Last Three Decades 233

Calymenina Swi01NERTO"i ...... Calymenacea (from Ptychoparida) Lichida MooRE ...... Lichadea (from Mesonacida or Zacanthoidae ?) Odontopleurida vVHITTINGTOl'< ...... Odontopleuridae (ditto.)

It is obvious that palaeontology de­ Catamarca, but according to HARRINGTON pends on palaeontography which de­ and LEANZA (1957) the Ordovician of perds in turn on fossils. Silicified Argentina comprises at present more material is a favourite of palaeonto­ than 130 species. Likewise, only about logists as it can yield by observations 35 species were known from the Cam­ a great deal of unexpected data espe­ brian of Siberia before the Atlas of the cially on the ventral morphology and leading forms of fossil faunas in USSR, ontogeny. During my stay at the U. S. Vol. l, Cambrian (1940) in which LER MON­ National Museum I saw some beautiful Tov A took part. Since 1950, however, new brachiopods extracted by Dr. CooPI::H. genera proposed for Cambrian trilobites In 1935 he sent me a photograph of from Siberia and Central Asia have silicified trinucleid which he had found numbered some 70 in total. It is in Virginia. Next year free trilobites predicted that described trilobites from from the Upper Ordovician of Perce, Australasia are only a small part of Quebec were illustrated in a paper by those which really existed ( 0PI K et aL CooPER and KINDLE. This line of in­ 1957). vestigation was greatly improved in A monumental work was published the United States. One cannot but by WALCOTT as earl y as in 1913 for the admire a free carapace with a hypo­ Cambrian faunas of China. Trilobites stoma, especially of a larva! form. of Eastern Asia were further amplified Although I do not intend to go into by l\1ANSUY, REED, Y ABE, SuN, SA ITO, details of descriptive works at this SI-II::NG, WANG, ENoo, REssER and others time, they were developed in various and recently by Hsu, Lu, CHANG, CHIEN, trends in these 30 years. Namely, many CHu, HsiANG, y, and others. In Japan ancient type specimens in Norway, Bohe­ trilobites are uncommon but Coronoce­ mia and other countries were precisely phalus and a few others were descri bed restudied; the Olenidae, Odontopleuri­ by HAMADA, Ico, 0KuBo and others. It dae and other selected families thorou­ is a remarkable fact that the Asio­ ghly revised; large faunas in Britain, Pacific faunas contain quite distinct Sweden, Esthonia, Rheinland, South genera and families, the Eoasidaspidae France and other classical areas mono­ by PoLETAYEVA for example. graphed; and innumerable new trilobi­ Here the trilobitology is reviewed in tes described from Palaeozoic areas connection with geology. BENsoN's which had previously been littel or not discovery of Cambrian trilobites in New well investigated. Zealand (1956) is crucially important RoEo ­ Much we owe to PauLSEN and T s for the reason that Ordovician has been soN for the knowledge of the rich the oldest dated rock among the Pacific Arctic faunas. Some 30 species of islands. Similarly, BuRAvAs' find of trilobites had been known from the trilobites at Tarutau, Southwest Thai­ Andine province befare 1935 when I land is invaluable in that the isle is described the Kainella faunule of Prairie the southernmost Cambrian locality of 234 Teiichi KOBAYASHI

Eurasia and at the same time these are Olenus, Hedinaspis and Glyptagnostus oc­ the oldest fossils in the Burmese­ cur in Korea all in dark carbonaceous ,Malayan geosyncline (1957). limestones along the axis of the Yoku­ A copious Lower Cambrian fauna sen geosyncline, I suggested that their was described from the Anti-Atlas by wide Eurasiatic dispersal was made BuPt (1952). It is interesting to see in possible with the aid of oceanic cur­ the type section of Amouslek that rents comparable to the Sargass sea of Neoredlichia occurs in the midst of the today (1943-44). It was emphasized olenelloid zones. In Australia on the further that the axial zone of the contray Redlichia is said to be earliest Appalachian geosyncline was the raute Middle Cambrian except in South of migration from the Atlantic to the Australia where it occurs in the Lower Cordilleran or the Andean province C2mbrian (C1PIK et al. 1957). Prior to (1957). WILso;-.; !1957) noted also the this, SAITO (1933) suggested that the cosmopolitan Olenidae in dark argil­ Redlichia stage in North Korea is lowest laceous geosynclinal sediments and Middle Cambrian since it is underlain jointly with Loci01A'.". he (1958) eluci­ by the Protolenus bed with disconformi­ dated the evolution and distribution of ty. SAITo's species was, however, later the Cambrian trilobites in North eliminated from Protolenus, s. str. In Amer i ca, in classifying their habi tats South China on the other hand it was into the cratonic, intermediate and ex­ clarified that various protolenoids evolv­ tracratonic realms. ed parallel to redlichids. Incidentally, it is note\'.;orthy that It is certain that the redlichids Asaphopsis, Taihungshania, S_vnhomalono­ migrated from Eastern Asia to North tus Coronocephalus, Crotalocephalus, Africa in the Olenellian epoch through Thysanopeltella, Dechenella and same the Himalayan trough. Probably Atlan­ other genera provide undeniable eviden­ tic Bailiella took the same path, becau­ ce for sea connection from Eastern se it is reported from South France, Asia to Europe or Australasia in the Kashmir, Tonkin-Yunnan border, Korea, Ordovician, Gotlandian or Devonian North China and Central Siberia. It is per iod. more certain that the Dorypygidae Now I recollect RAY.\10'-'o's address entered into Northern Europe from on Pre-Cambrian Life (1935) in which he Eastern Asia through Central Asia spake of the diversity of naked pelagic ilvsHIN, 1953), because the family is animals in the late Pre-Cambrian period well represented in Kazakstan and and their armouring at the transition West Siberia. It is understandable to the Cambrian due to their benthonic that Centropleura could migrate from adaptation on shallow bottom and the the Atlantic province to New Siberia superiority in struggle for existence and Central Siberia, but bow Centro­ which took place by over-population. pleura reached Australia from Asia This interpretation applies to trilobites remains a puzzle. as well as other animals. Fossil re­ As discussed elsewhere (1949), it is cords in the transitional epoch are still remarkable that the occurrence of meager, but medusae and annelids were Glyptagnq�tus reticulatus in four con­ lately discavered in South Australia tinents indicates. the oldest world in­ far below the archaeocyathid limestone stant in the geological age. Because (GLASSNER, 1959). In my opinion the Studies on Tritobites in Last Three Decades 235

Proterozoic glaciations causing changes also to the Polymera. Rules on hyper­ of hydrosphere not only in areal exten­ trophy of the axial lobe and caudaliza­ sion but also in variation of environ­ tion of post-cephalic segments also ments, most probably favoured this meet with few exception. In the future, important step in the development of combination of such rules will make it aquatic life. It is also remembered possible to decipher the tangled history that the Neo-Cryptozoic eon is com­ of evolution. parable with the whole Phanerozoic eon I shall close my speech with a few in time length (1944-45). words of reference to some new com­ At all events four primary sto:.:ks of pilations. GRABAu and SlltMcR'S Index trilobites appeared in the early Cam­ Fossils of North America was completely brian epoch among which the shortest revised and reillustrated by SHL\1ER and survivors were the Redlichida, probably SHROCK (1944). Publications of this followed by the Corynexochida and kind were compiled for the Cambrian then by the Agnostida. It is, however, of U.S.S. R. by VoLOGDIK (1940), for the an important problem, whether the Palaeozoic of Western Siberia by Corynexochida really disappeared be­ KHALFIN (1955) and for Fossil lnverte­ fore the Ordovician period, because the brates of China by Academia Sinica order flourished most in the insufficient­ (1957). These two Soviet publications ly explored As io- Pacific province and contain many new genera and species because the phylogenetic position of by LERMONTOVA and others. STØRMER the Damesellidae, Leiostegiidae and (1949) and HuPf (1953) presented a Komaspiidae remains unsolved. The chapter on Trilobita respectively in origin of cheirurids, phacopids, odonto­ GRAsst's Traite de Zoologie Tom. 6 (1949) pleurids and lichids is still unknown. and PivETEAu's Traite de Paleontologie In view of the resemblance of the Eo­ Tom. 3 (1953). HuPf's Classification des acidaspidae to the Corynexochida, how­ Trilobites (1953, 55) and HARRI'-IGTON and ever, I think future researches in the others' Trilobita in MooRc's Treatise Asio-Pacific province may throw light (1959) give the most comprehensive in­ on the derivation of certain secondary formation on the class but for Asiatic stocks from the primary. genera it is hoped more supplementary The rise and fall of trilobite families information will be gathered to com­ took place on the !argest scale during plete our knowledge. the late Cambrian and early Ordovician

epochs. All of the Cambrian families References died out by the end of the Ordovician period, while some forerunners of the CJIA:':G, H. T. (1921), Lapidarium Sinicum, post-Cambrian families appeared already etc. Mem. Geo!. Surz•. China, Ser. B, No. 2. in the latter part of the Cambrian BEECHER, C. E. (1897), Outline of a Natura! period. The evolution of trilobites is Classification of the Trilobites. Am. jour. so highly complicated that it can hard­ Sei. 4, Vol. 3, No. 13. ly be unified by any theory. However, BE'JSO:-J, W. N. (1956), Cambrian Rocks and the rule of effacement, that is, that Fossils in New- Zealand, (Preliminary effacement advances from the distal to Note). El Sistema Cambrico, etc. Sympo­ the proximal part of a shield (1939), sium, Pt. 2. XX Congr. Geo!. Intern. Mexico. applies not only to the Miomera, but GLASSNER, M. F. (1959) , The Geology and 236 Teiichi KOBA YASHI

Late Precambrian Fauna of the Ediacara the McKay Group in British Columbia, Fossil Reserve. Rec. South Austr. Mus. \Vestern Canada, with a Note on the Vol. 13. Early Ordovician Palaeogeography. f our. HE�NINGSMOEi\', G. (1951), Remarks on the Fac. Sei., Univ. Tokyo, Sec. 2, Vol. 9, Pt. Classification of Trilobites. Norsll geo!. 3. tidsskr. 20. Lr.RMONTOVA, E.V. (1940), Arthropoda, in HAMADA, T. (1959), Gotlandian Shelly Fauna VoLOGDIN, A. et al. Atlas of the leading from SoL!thwest Japan, l. Coronocephalus forms of the fossil faunas of the USSR. l, lwbayashii, a new species from the Kura­ Cambrian. oka District. Kyusyu. Japan. jour. Geo!. Locr·IMAN-BALK, C. and WILSON, J. L. (1953). Geogr. Vol. 30. Cambrian Biostratigraphy in North HARRINGTo:--:, H. ]. et al. (1959), Trilobita, America. jour. of Pal. Vol. 32, No. 2. in MooRE's Treatise on Invertebrate Fale­ Lu, Yen-Ho (1957), Trilobita, in Index Fossils ontology, Pt. O, .4Ytlzropoda l. of China, Invertebrates. Vol. 3, compiled HARRINGTON and LEA:"ZA, A.F. (1957), Ordo­ by Acad. Sinica. vician Trilobites of Argentina. Dept. of OPIK, A. et al. (1957), The Cambrian Geolo­ Geo!. Univ. of Kansas, Sp. Publ. l. gy of the Australia. Comm. of Australia, HcPI':, P. (1952), Contribution a l'Anti-Atlas Bur. of Min. Resources, Bull. No. 49. Marocain. Notcs et Jlem. No. 103, Serv. Po:vtPECKJ, ]. F. (1898), Ueber Calymene geo!. Maroc. BRONGNIART. Neues fahrb. fur Min. usw. -- (1953, 55), C!assification des Trilobites. ]ahrg. 1898, Ed. l. Ann. de Pal. Tom. 39. 4 1. PouLSEN, C. (1923), Bornholms Olenuslag hsHIN, N. K. (1953), Midd le Cambrian Trilo­ og deres Fauna. I)_enm. geo!. Unders. Ser. bites of Kazakstan. Pt. l. A/lad. Nauk 2, No. 40. Kazakstan USSR. RASETTI, F. (1952), Ventral Cephalic Sutures ]AEKEL, O, (1909), Ueber die Agnostiden. in Cambrian Trilobites. Am. jour. Sei. Zeitsch. deutsclz. geo!. Gesell. Ed. 6 l. Vol. 250. ]EGOROVA, L. I. et al. (1955), Trilobita in RAYMOND, P. E. (1920), The Appendages, L. L. K HALFI:--:'s Atlas of important forms Anatomy and Relationships of Tri lo bites. of the fauna and flora of West Siberia, Tom. Conn. Acad, Arts Sei. Mem. Vol. 7. ]. -- (1935), Pre-Cambrian Life. Bull. Geol. J\:oBAYASHI, T. (1935). The Cambro-Ordovi­ Soc. Am. Vol. 46. c:ian Formations and Faunas of South REED, F. R.C. (1898), Blind Trilobites. Geo[. Cho�en, Palaeontol. Pt. 3, Cambrian Mag. Vol. 5. Faunas of 'South Chosen with special RrcHTER, R. (1932), Crustacea, in Handworle1·­ . Study on the Cambrian Tri!obite Genera buch der N_aturw. 2te Aufi. and Families. jour. Fac. Sei., Jmp. Univ. SAlTO, K. (1933), The Occurrence of Protole­ Tollyo, Sec. 2, Vol. 4, Pt. 2. nus in the Cambrian Rocks of North -- (1936), Proparian Genus of the Oleni­ Korea. _Tapan. jour. Geo!. Geogr. Vol. JO. dae and i ts Bearing on the Trilo bite ST

in MOORE's Treatise on Invertebrate Pal­ WHITEHOUSE, F. W. (1936, 39), The Cambrian aeont_ Pt- O, Arthropoda, 1. Faunas of Northeastern Australia, Pts. STUBBLEFIELD, H. H. (1915), Cephalic 1-3. Mem. Queensland !ffus. Vol. 11. Sutures and their Bearing on Current WHITTINGT0:'-1, H. B. (1957), The Ontogeny Classification of Trilobites. Biol. Rev. of Trilobites. Biol. Rev. Vol. 32. Vol. 11. WILSON, J. L. (1957), Geography of Olenid SwiN:'-IERTON, H. Il. (1915), Suggestions for Trilobite Distribution and its Influence a Revised Classification of Trilobites. on Cambro-Ordovician Correlation. Am­ Geo!. Mag. N. Ser. Vol. 2. jour. Sei. Vol. 255. Three Trilobi te Families At RAYMOND's Garden, Aug. 4th, 1932. From the left side. Dr. Leif STsz\RMER, Miss RAYMOND, Mrs. STsz\ RMER, Mrs. RAYMOND, Mrs. KoBAYASIII, Prof. Percy E.RAYMOND and the Author.