Worms are never wrong!

50 years of polychaete studies

Kristian FauchaldDepartment of Invertebrate Zoology

National Museum of Natural History

Smithsonian Institution

Biogeographic pitfall

• Primary record:

– G.O. Sars: “I found this specimen among material left over from my father, presumably from western Norway”

• First citation:– Canon Norman: “This species has been reported from western Norway”

• Secondary citation:– No names to protect various sensitive National egos: Bergen

• Blame to go around: • Papa Sars for not labelling his material; Baby Sars for describing a

species from an unknown location.• Norman and the “unknown citer” for being inaccurate in their

citations.

What did we know? (I)

• Genetics - fruit-flies and peas• Benthic ecology - Parallel bottom

communities (fide Gunnar Thorson)• Invertebrate zoology

– Libbie Hyman’s first 3 volumes were out, echinoderms in 1955; aschelminths in 1959

– Beklemishev in Moscow and Remane in Germany

• Biogeography – Sven Ekman ruled the seas (1935 in German, 1953 in English)

What did we know? (II)

• Systematics – – We read Mayr and Simpson -- and believed most of

what we read!– Hennig first issued in 1950, in German, to English in

1966. We knew no cladistics, no phenetics, no molecular systematics and got no background in theory.

• Physiology – Krebs cycle known; the role of haemoglobin in

electron transport mostly understood; role of haemoglobin in polychaetes “poorly understood”; photosynthesis not yet fully elucidated.

Instrumentation etc.

• We had compound and stereo microscopes. Drawing apparatuses were cumbersome; photography too expensive to waste on students.

• Transmission EM just developing beyond experimentation.

• Scanning Electron Microscopes or Confocal Microscopes did not exist

• Computers – In Bergen the two-room UNIVAC could, provided that the radio-tubes had not popped, do minimal math (tic-tac was the most exciting computer game other than chess).

1950’s polychaete systematists(a not-so-random selection)

• Pierre Fauvel (active 1895-1958) - France

• Enrique Rioja (active 1916 – 1962) – originally Spain, Mexico

• Pavel Uschakov (active 1923 – 1984) – Soviet Union

• John Day (active 1932 – 1984) – South Africa

• Elise Wesenberg-Lund (active 1934 -1962) - Denmark

• Olga Hartman (active 1936-1973) - USA

• Carl Støp-Bowitz (active 1945 – 1992) - Norway

• Marian Pettibone (active 1953 –1997) - USA

When critizing earlier scientists, please remember….

• If only two taxa are known, one character with two states is all that is needed to keep them apart

• As more taxa are found, descriptions become complex. Complexity also linked to the quality of the microscopes.

• We probably have too many taxa to distinguish in relation to our capability to distinguish them.

• Deflating a feature as a character is usually a personal bias and should not be accepted without documentation

• Most scientists retain the science style they develop early in life. We will always have both old and young scientists working on any group and thus lots of variation in styles.

Morphology linked to systematic structure?

• Many morphological differences in a taxon (e.g., polynoids, ampharetids) yields many genera with (relatively) few species in each; trend especially seen over the last 100 years.

• Limited morphological differentiation (e.g., lumbrinerids, cirratulids) often yields many new species in few genera.

• Capitellids are unique: Genera are largely defined on combinations of numbers of thoracic segments and number of segments with capillary chaetae. Very nearly each new species described gets its own new genus.

• IS THIS GOOD TAXONOMY? PROBABLY NOT

How Many Polychaetes?

• Hartman (1959) handled roughly 10,000 names, considered 5341 as currently acceptable.

• Fauchald (ca. 2000) found 14,400 original names and more than 20,000 combinations of genus and species names; estimated number of currently acceptable species ~ 7,000.

• Considering what I know about unidentified material in collections, I estimate that there must be another 4,000 to be described, so we still have a ways to go.

Traditions in s/m studies

• Primary faunistic studies such as Grube’s Philippine study (1878); Claparède’s Gulf of Naples studies (1860’s), most of Hartmann-Schröder’s papers and Hartman’s studies.

• Reviews of local faunas: Faune de France, Tierwelt Deutschlands, Fauna of India, Day’s Polychaeta of southern Africa; Hartman’s Atlas’s.

• Morphological/systematic reviews of single taxa, I.a., Eisig’s 1887 of capitellids, Darboux’s 1900 on scale worms, Gustafson’s 1930 on amphinomids and euphrosinids.

• Morphological studies of organ-systems: Racovitza on prostomia; Hanström on anterior nervous systems; Goodrich 1890’s and 1946 on nephridia.

Recent studies

• World-wide reviews focused on systematics (Blake, Fauchald, Fitzhugh, Glasby, Hutchings, Pettibone, Pleijel, Salazar-Vallejo)

• Regional systematic studies with overviews of the rest of the world (Hutchings, Imajima, Orensanz)

• Continued morphological studies e.g., anterior nervous system (Orrhage), nephridia etc (Bartholomaeus

• Unusual environments (Desbruyères, Blake, Miura, Pettibone), especially from deep water

• Development of interactive keys (Glasby, Fauchald, Hutchings, Wilson)

• Comprehensive or focused cladistic studies (Fitzhugh, Pleijel, Rouse and in part Fauchald)

Some philosophical issues

• Do scientists ever change their minds? Kuhn (1962) and paradigm shifts in a polychaete setting.

• Paraphyletic vs. monophyletic taxa, does it make a difference (except esthetically and emotionally)?

• Does the traditional systematic (Linnean) system work? If not, what can take its place?

• Scoring problems: Can we represent complex visual observations with a single number for all characters or only for some kinds of characters?

A few rules

• Include author and publication year as part of the name at least once in a paper (quadrinomials).

• List literature used for identification.• If you propose a synonym, you must have seen

types or material from the type area.• Include only citations for which you know that

voucher material is available; including databases or papers from the grey literature.

• Don’t worry about ranks: The sooner we forget them, the better off we will be.

• Illustrate, photographs are lovely but line-drawings often convey more information.

Homotypic and heterotypic synonyms

• Homotypic synonyms come about when a name is nomenclaturally incorrect or sometimes when a species is moved from one genus to another. Homotypic synonyms have a single (set of) type(s). One name is valid; other name(s) are invalid with reference to that type lot. Homotypic synonyms concerns names or combinations

• Heterotypic synonyms reflect a scientific opinion about distinctness of (terminal) taxa. Heterotypic synonyms always have different sets of types. One of the taxa is the currently accepted taxon.. Heterotypic synonyms concerns most often taxa at the terminal or subterminal levels

More about synonyms

• Synonymy-lists contain three different elements, homotypic synonyms, heterotypic synonyms and mis-identifications.

• A synonym involves the whole taxon; a mis-identification is an error by a scientist in applying a name to one or more specimens.

• If previously mis-identified specimens belong to an undescribed species, the taxonomic act is description of a new species, NOT a new name.

• The term “new name” is appropriate when only the name is being changed, while the taxon remains unchanged

IS POLYCHAETA MONOPHYLETIC?

NO!Probably not

ANNELIDA

• Includes Scolecida, Palpata, and Echiura• Scolecida, in addition to some “polychaetes” includes the

clitellates• Palpata includes all other “polychaetes” and can be

separated into two: Aciculata and Canalipalpata.• Pogonophora/Vestimentifera is a clade in Sabellida • Lumping and splitting various groups, especially of

canalipalpates will continue for some time.• • Beware of analyses in which the starting point is a

theoretical construct!

Comfort for conservatives:

• Birds, reptiles and amphibians were shown to be paraphyletic a long time ago. Scientists still consider themselves as ornithologists and herpetologists.

• Shared literature, shared collections and shared sampling methods and locations keep these groups together.

• So, some concepts, even when unsupported scientifically, remain in use for historical and practical reasons.

Systematics as Comparative Biology

• Two flavors: Conceptually innovative and Aggregation of data points. Most studies include a bit of both, but tend to be focused on one flavor.

• New thoughts without data are just as bad as piling up data points

• Think of your study objects as living organisms.

• Without knowledge of the rest of science, and philosophy, we are unlikely to contribute much beyond data points for others to analyze or forgotten throughts.

Recent problems

• Food uptake is less linked to anterior appendages than previously assumed

• Sperm transfer organs are far more common than assumed

• Sperm storage organs are present in a variety of polychaetes

• Planktotrophic larvae are less common than assumed; direct development more common

Furthermore….

• Some taxa appear to be rare no matter where we look.

• Bacteria participate in food processing in far more species than we had previously anticipated.

• Some geographical areas appear to be depauperate, others unreasonably rich in species. Each unusual pattern may be the consequence of historical accidents

EchiuraEuarthropodaOnychophora

Apistobranchidae

TrochochaetidaeLongosomatidaeMagelonidae

Chaetopteridae

SPIONIDASpionidae

Poecilochaetidae

SiboglinidaeSabellariidaeSabellidaeSerpulidaeOweniidae

AcoetidaeAphroditidaeEulepethidaePolynoidaeSigalionidaePholoidaeChrysopetalidaeGlyceridaeGoniadidaeParalacydoniidaePisionidaeLacydoniidaePhyllodocidaeNephtyidaeNereididaeHesionidaePilargidaeSphaerodoridaeSyllidae

AmphinomidaeEuphrosinidaeDorvilleidaeLumbrineridaeEunicidaeOnuphidae

Cossuridae

ArenicolidaeMaldanidaeCapitellidaeOpheliidaeScalibregmatidaeOrbiniidaeParaonidaeQuestidae

Clitellata

Sipuncula

SABELLIDA

AcrocirridaeFlabelligeridaeCirratulidaeAlvinellidaeAmpharetidaePectinariidaeTerebellidaeTrichobranchidae

TEREBELLIDA

PHYLLODOCIDA

EUNCIDA

A C I C U L A T A

P A L P A T A

P O L Y C H A E T A

A N N E L I D A

A R T I C U L A T A

C A N A L I P A L P A T A

73

COLECIDA

S

New systematization in Rouse and Fauchald 1997

And, that’s all, folks!