Taxonomic Development Nematoda Gerlach

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Vertt Inst. M eeresforsch B rem erh 18. 249 - 255 (1980)Fram the Institut fr Meeresforschung B rem erhaven

Development ofMarine Nematode Taxonomy up to 1979Sebastian A Ger I ach

Abstract: Up to 1915 only4, and until1935 only 14 scientific papers on m arinenematodes per year had been published; the number of publications rose toabove 40 since 1970, presenting about 100 new species of marine nematodesevery year.. Before 1910, there were never more than 5 scientists publishingpapers on marine nematodes within five year periods.. Since 1960 this figureis above 20, and since 1970, above 50 In spite of this remarkable increase ofman power in marine taxonomy, the estimated number of unkown species ishuge and many years from now will pass before they are all described In anyoceanic region with a wide spectrum of biota fram shallow to deep water onecan reckon with more than 1000 nematode speciesNematodes are the most numerous metazoan animals on the sea noor;their biomass in the deep sea and in some brackish regions equalsmacrofauna biomass, and they play important roles in the food websand in the productivity of the oceans,. Consequently, with increasinginterest in marine ecosystems, more and more ecological studies re-garding m arine nem atodes have been conducted., But who can identifythe genera and species of freeliving nem atodes? In the follow ing pagesand graphs I w ill provide a short numerical review of scientists who didwork on marine nematodes in the past, and on the quantitative deve-lopm ent of m arine nem atology.

Accep ted for p rin tin g 2 6,.3 .19 80A ddress of the author: Prof.. D r.. Sebastian A Gerlach, Institut fr M eeresfor-schung, Am Handelshafen 12, D 2850 Bremerhaven, Federal Republic ofGermanyOpening address at the Second Symposium on Aquatic Nematodes, Bremer-haven 28 - 31 May 1980,

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Tl 4 26 521 4 19 6number of taxa described

p er p en tad 15 212 2 92

1870 80 90 1900 10 20 30 l,0 50 60 70

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by a during World War 11.After the war rateagain to - 20 per year (Fig. 1). During the period 1971 - 1975,212papers have been published, which is a rate of about 42 per year; thetrend continues: in 1976, we registered 35, and in 1977, 52 papers.Fig. 1 also includes the numbers of taxa described within all pentadssince 1865. These data include the marine and nonmarine NematodaAdenophorea without Dorylaim ida. Trends are sim ilar to trends ofpapers published, reaching 125 taxa described per year in the period

'--n;jCl> >E QIa .J < U

~ ~f I

10 0num ber of paperspublished per pentad

/t '

/~ ~~ . ~./ \/'-. . ./"---/ ."'--.""---'-'-./ / 32 8 31 9

12 0

80

60

40

20

Fig. 1: Development of aquatic nematology 1865-1975: Number of paperspublished on marine nematodes, and number of taxa established forNematoda Adenophorea excluding Dorylaim ida during periods of 5years (pen tads) .

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I1S ~

NUl1--'

000...0..o P'CI' >-i;:r>-,roro;:+;":;Cl'roNo...o...roro -. 0cP : :: :s ;: r

1 8- -D ec ra em er 1 97 1. -8~Sergeeva 1 9 7 2 -9 ",--- Bove"e 1972 -20-B elogurov/a 1972 -1O-Boucher 1970-18 -WarWlck 1969-

9 0tt 1967-11.--Hope 1967-24-'~Vi!iello 1967-

25 -~ Lorenzen 1966-28 -'--'- R ie ma nn 1 96 5-16 -, Murphy 1963-20---'--Hopper 1961-

12-- -Platonova 1958-19 Ingtis 1958-

25--- Timm 1951 -32-_M~__- - - W ie se r 1 95 1 -63 --Gerlach 191';9--Oe Conlnck 1930-

P R O D U C T I V E P E R I O D O F M A R I N E N E M A T O L O G I S T SW H O P R O D U C E D M O R E T H A N 8 P U B L I C A T I O N S

16 21 2

202 2 C h i t w o o d 1931-196412-Schulz 1931-1951

33 - S t ekhov en 1929 -1956A U g e n 1925-1960K r ei S 1921. - 19 63

1716

1 2 -O itlevsen 1911-19318 - Schneider 1906-1927

1 0- Lm st ow 1 89 2- 19 08

F il ip Je v 1 9 16 -1 94 6S te me r 1 91 5- 19 58

4021

C o b b 1890-1933O e M an 1 87 6- 19 28 n um be r o t m an ne n em ato lo gls ts p ro du ctlv e w ith in a p en ta de

I 4 [ 4 I ' I 4 I J I 7 I 6 I 7 I 9 [ 12 I 14 I 12 I 9 I 7 I 9 [ 14 I 17 [ 20 I 23 I 481875 1 880 1890 1900 1910 1920 1930 1940 1950 1960 1970Fig. 2: Penods of scientific productJvity of those nem atologlsts w ho up to 1 97 8 h ad p ub lish ed8 and m ore papers on m arine nem atodes. The figur es at the bottom of the graph list thetotal number of nematologists who published within each pentad papers on marinenema todes a it oget he r.


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Tab 1: S cientists w ho published papers on m arine nem atodes in the1971-1975 ,and newcomers a fte r 1976,

Austria Ott Switzerland Altherr "tWieser UK Coles

Belgium Oe Coninck MooreOecraemer PlattHaspeslagh Ward 41von der Heiden WarwickLippens USSR Alekseev O

Bulgaria Stojkov (1976) BelogurovUzunov BelogurovaGaltsova

Oenmark Jensen (1976) Iv an eg a (1 976)MalakovFrance Boucher Platonova

Bovee Serge evaVitiello TchesunovVivier Zakhidov

Germany, Brenning USA HopeOemocratic M urphyRepublic N ichols (1979)SiddiqiGermany, BIome TietjenFederal Freudenhammer ViglierchioRepublic Gerlach CanadaLorenzen BUH

RachorHopper

Riemann WebsterSchrage India Jaya sre e (1976)Bangladesh TimmHungary Andrassy Philippines JuarioJapan K ito (1 976 )Roumania Groza-Rojankowski Australia Inglis Fig

Onciu New Zealand Yeates

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13

40

DEEP SEA 111.:>2.

:1,0031

;2

Fig 3-4: G eographical distribution of nem atode species described prior to 1972,from marine ecosystems. Figures show the number of valid speciesand subspecies reported fram different regions of the world oceansand co asts

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between 1951 and 1960. After 1960, however, there were less taxadescribed, and not before re cent years are high numbers again achiev-ed: 111 taxa per year in the pentad 1971 - 1975, 109 in 1976,89 in1977.. It is evident that the m ore sophisticated requirem ents of m oderntaxonomy make descriptions more time consuming for taxonomists.Until about 1910, there was not one five years period with more than10 different scientists publishing on m arine nem atodes.. It w as as late as1955 that the number of contemporary nematologists increased to 15,and it is only 1960 that the figure increased above 20 (Fig. 2).. In thepentad 1971 - 1975, however, not less than 50 marine nematologistswere publishing papers, and since 1976,6 more names have to be addedto the list (Table 1)In this list, of course, scientists are included who are not continuingtaxonomie work on freeliving marine nematodes because they con-tinue their professional careers in other fields. Fr com parison, in Fig. 2those scientists have been listed with their productive life span whocontributed 8 and more publications.. Before 1915, there were nevermore than 4 scientists of this category publishing within one five yearsperiod, prior to 1925, the number was below 6, and it did not increaseabove 8 before 1965..B y 1970, how ever, the number of regularly publish-ing marine nematologists increased to 13, and today the compilation is20.The criterion chosen, 8 papers published, is highly questionable; it iscertainly not good to evaluate the quality of a scientist and the progressof science that he contributed, by counting the mere number of hispublications But a general tendency seems to be obvious: like otherfields of seien ce, marine nematology was having a boom in the pastyears.One should, however, be realistic about this increase of manpowerin marine nematology. The number ofmarine nematode species knownis roughly 4000, but in every sampie from the sea one finds a fairly largepercentage of undescribed species, which is w eil above 50 % in the deepsea and in such geographical regions that have been poorly sampled(Fig.3 - 4)..T he number of species in w eil known areas like the Medi-terranean (637 recorded), or the North Sea (456 recorded) is probablyabove 1000 It is legitimate to assurne that more than 1000 nematodespecies can be encountered in any region of the world's oceans whichprovides a wide spectrum ofbiotopes from shailow to deep water. Even254

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if at present we have no eloser knowledge of the geographie range ofnematode species, this argumentation perm its an estimate that morethan 20000 taxa of marine nematodes remain undescribed. Supposethat a diligent taxonom ist could describe 200 new nematode speciesduring30 years of his professional career, that m akes 4000 new speciesfor 20 taxonom ists in 30 years It would require 5 generations or 150years to describe them alL It is pleasant to know that there will be somework left o ver fo r our great-grand ch ildren

ReferenceGedach, S A and F Riemann (1975 - 1974): The Bremerh av en check list o faquatic Nematodes, a catalogue of Nematoda Adenophorea excludingthe Dorylaimida.. Verff Inst M eeresforsch Bremerh. Suppt 4: 1 -736

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Taxonomic Development Nematoda Gerlach