Mark Wetzel crouching in cave
Photograph of me taken by Dr. Steven J. Taylor during collections for aquatic oligochaetes and other cave fauna in Fogelpole Cave, southern Illinois (November 1999).    Steve is an experienced biospeleologist with whom I have collaborated on a variety of projects.

Welcome to my home page.  I am a Research Scientist (now semi-retired) with the Illinois Natural History Survey * in Champaign, Illinois USA.

As an aquatic biologist, I collect and identify insects and non-insectan macroinvertebrates, as well as fishes, plankton, and unionid mussels that inhabit rivers, streams, springs,  seeps, caves, other groundwater habitats, wetlands, ponds, lakes,  impoundments, and phytotelmata.  I have a systematic interest and taxonomic expertise with the freshwater species in the Phylum Annelida—the true-segmented worms.  Groups in this phylum with which I am most familiar include the Aeolosomatida (suction-feeding worms) [Polychaeta: Aphanoneura]; the Branchiobdellida (crayfish worms), Hirudinida (leeches), and microdrile oligochaetes {primarily aquatic oligochaetes} [Clitellata]; and the megadriles – including most earthworms [Crassiclitellata].

Prior to retirement from full time employment, my primary responsibility at the Illinois Natural History Survey involved collaboration with several other aquatic biologists (aquatic entomologists, malacologists, herpetologists, and  ichthyologists) in the surveys of stream and lake systems that may be affected by construction or rehabilitation of bridge and highway projects by the Illinois Department of Transportation (IDOT) throughout the State of Illinois.  The INHS Biological Surveys and Assessment Program (BSAP) works with IDOT to minimize the effects of transportation infrastructure building and maintenance on local plants and animals. Through the conduct of these surveys, the current as well as historical status of both native and introduced aquatic fauna in these various habitats, with particular emphasis on species that are listed or under consideration for listing as endangered or threatened by the State of Illinois or the U.S. Department of the Interior, Fish and Wildlife Service.  We were also responsible for water quality monitoring at selected stream sites associated with IDOT projects. 

From 1991 until he passed away (September 2013), I had been collaborating with Dr. Donald W. Webb and other scientists at the INHS and the Illinois State Geological Survey in a long-term study of the biodiversity, hydrogeology, and water quality of springs in Illinois.  Since the late 1970s, I have served as the curator and collections manager for the INHS Annelida Collection, which now holds ~350,000 specimens representing all 50 U.S. states, most Canadian provinces, Puerto Rico, Bermuda, Mexico, and 14 other countries.  Other research projects have involved surveys for avifauna, plants, and mammals, and radio-tracking of bats and moose.

Since retirement, I have continued focus on small research projects highlighted elsewhere on this website, as well as continued as the curator and collections manager for the INHS Annelida Collection; I also assist with the editing of reports associated with the INHS-IDOT Biological Surveys and Assessment Program.

Other important research projects include the distributions of aquatic and terrestrial oligochaetes in the Huron Mountain area (Marquette County in the upper peninsula of Michigan) funded in part by the Huron Mountain Wildlife Foundation (2010-present); Great Smoky Mountains National Park (1999-2005); Grand Canyon National Park (1991-2006); Yosemite National Park (2016); Blue Ridge Parkway (2005, 2017); in spring, cave, and other groundwater habitats throughout the U.S., and earthworms of Nachusa Grasslands preserve in Illinois. Links to project summary pages for our surveys in these areas are provided under Research in the navigator bar at the top of this page.

For the last several years, I have been collaborating with Dr. John Reynolds (Oligochaetology Lab, Kitchener, Ontario, Canada) on several projects:

1) Annotated checklists of the megadrile earthworms of North America.  The first edition was published in March 2004 in the journal Megadrilogica [Vol. 9(11): 71-98].
> In December 2008, we published an update of that 2004 paper in Megadrilogica [Vol. 12(12): 157-208], expanding its scope to include distribution records for earthworms occurring in Bermuda, Hawaii, Mexico, and Puerto Rico.
> A second update was published in July 2012 in Megadrilogica [Vol. 15(8): 191-211]. In that paper we recognized 256 species representing 59 genera in 10 families; of these, 188 are considered native to North America while 68 are considered to be introductions.  A third update is now in preparation.

2) In December 2011, we published an annotated checklist of the megadrile earthworms of Illinois in Megadrilogica [Vol. 15(4): 35-67]. In that paper we reported records of 38 species earthworms (six families, 18 genera) from 79 of the 102 counties in the State; of these, 18 are considered native to North America while 20 are considered to be introductions. The type localities for eight of these species are in Illinois. We are now conducting surveys for earthworms in the 22 counties in Illinois from which no earthworm records had previously been reported or were available for review, as well as in other counties from which limited records were available. A second, updated paper on the earthworms of the state is in preparation.

3) On Monday 6 January 2014, Mark J. Wetzel (INHS) and John W. Reynolds (Oligochaetology Lab, Kitchener, Ontario, Canada) launched a new website presenting the second edition of Nomenclatura Oligochaetologica, entitled
Nomenclatura Oligochaetologica – a catalogue of names, descriptions, and type specimens of the Oligochaeta. Editio Second. 

This web-based Second Edition of Nomenclatura Oligochaetologica [N.O.2]:

  • integrates the accounts included in the first volume (Reynolds and Cook, 1976 [N.O.]) with those presented in the three supplements (Reynolds and Cook, 1981 [N.O.S.P.], 1989 [N.O.S.S.], and 1993 [N.O.S.T.]) – together comprising the original first volume N.O. series;
  • updates and corrects accounts for the generic, subgeneric, specific, and infra-specific names of oligochaetes (Annelida, oligochaetous Clitellata) as presented in the original first volume N.O. series;
  • adds accounts for oligochaete taxa described as new to science since the publication of N.O.S.T. in 1993 – including barcode, tissue repository, other pertinent DNA sequencing information, DOI links to the publications in which new descriptions are presented, and links to GenBank records for the new taxa;
  • expands the Prolegomenon, Gratiarum Actiones, Praefatio, Index Auctorum, Index Auctoritatum, Index Museorum, Glossarium, and References sections of the original first volume series;
  • includes translations (in 12 languages) of the Prolegomena and Glossaria of the original series and this second edition;
  • presents and expands the Dedicatio section in the original series with biographies and memoria for our historical and contemporary colleagues focused on oligochaetology, including bibliographies of their published scientific and lay contributions;
  • offers a forum entitled Current Perspectives where titles and abstracts for papers focusing in oligochaete phylogeny, taxonomy, systematics, and nomenclature are highlighted;
  • provides a Using This Nomenclator section with account examples and instructions for using and navigating this web-based catalogue; and
  • presents a For Contributors page encouraging visitors to and users of information throughout this web-based nomenclator to provide us with additions and corrections to the accounts as presented in the Nomenclator Generum, Nomenclator Subgenerum, Nomenclator Specierum, as well as additions and corrections to the information presented elsewhere on this website;
  • include an annotated list of links to web-based annelid resources; and
  • add an Annual Accounting page summarizing the number of accounts for newly described taxa (genera, subgenera, species, and subspecies) that have been added (1990–present).

4) John Reynolds and I recently completed surveys for earthworms in the Huron Mountains in the Upper Peninsula of Michigan (2013–2014). In December 2014, John and I published a checklist of earthworms for the state of Michigan [Megadrilogica 17(5): 51-72]; another paper specifically summarizing the results of our surveys for earthworms in the Huron Mountain region is in preparation.

5) In collaboration with Will K. Reeves and John W. Reynolds, we are now finalizing a paper on the distribution and ecology of the limicolous earthworm family Sparganophilidae in North America (to be published in early 2024).

6) As associate editor, I assist Dr. Reynolds with the editorial responsibilities of the journal Megadrilogica. A navigator bar at the bottom of the journal’s homepage provides links to an index of all volumes and issues published to date, tentative titles and authors for papers now in press, and links to a few other websites with information pertinent to the study of terrestrial oligochaetes.

I have been a member of the International Symposia on Aquatic Oligochaeta (ISAO) group since its first triennial meeting hosted by Ralph O. Brinkhurst in Sidney British Columbia, Canada in May 1979; in late 2007, I was elected to serve as the first General Secretary, ISAO.  During ISAO 14 (Japan, September 2018) I nominated Adrian Pinder to serve as the second General Secretary, ISAO – which was unanimously approved.  Dr. Pinder assumed the duties of this position during the business meeting of ISAO15 on 24 September 2022. 

  • The 16th ISAO meeting, to be hosted by Dr. László Molnár, is tentatively scheduled to convene at the Balaton Limnological Research Institute on Lake Balaton, Tihany, west-central Hungary, in September 2025. Additional information will be presented on a symposium website, to be established in 2024. 
  • The 15th ISAO meeting,  hosted by Dr. Patrick Martin, recently convened at the Royal Belgian Institute of Natural Sciences, in Brussels, Belgium, 20-24 September 2022. [originally scheduled for September 2021, the organizing committee postponed this symposium for a year because of the pandemic].  The proceedings for this 15th ISAO symposium (edited by P. Martin, A. Pinder, and M.J. Wetzel) were published in the journal Zoosymposia, Volume 23, on 10 July 2023; all papers included in this volume are available, open access (no cost).
  • The 14th ISAO meeting, organized and hosted by Dr. Akifumi Ohtaka and other colleagues, convened at Hirosaki University, Aomori Prefecture, Honshu, Japan, 10–14 September 2018.  The proceedings for this symposium were published in the journal Zoosymposia, Volume 17, on 17 February 2020; all papers included in this volume are available, open access (no cost).
  • The 13th ISAO meeting, organized and hosted by Dr. Jana Schenková, convened at Mazaryk University in Brno, Czech Republic, 7-11 September 2015.  The proceedings for this symposium were published in the journal Biologia, Volume 71, in January 2016; all papers included in this volume are available, open access (no cost).
  • The 12th ISAO meeting, organized and hosted by Adrian Pinder, convened in Fremantle, Western Australia, 9-13 September 2012.  The proceedings for this symposium were published in the journal Zoosymposia, Volume 9, on 12 June 2014; all papers included in this volume are available, open access (no cost).

The Illinois Natural History Survey Biological Collections

The Illinois Natural History Survey Biological Collections are world-renowned and are among our institution’s most important physical assets. Most notable are the insect, plant, fungi, fish, mollusk, amphibian and reptile, crustacean, mammal, bird, paleontological, and annelid collections. These collections serve as an historical record of our living natural resources, are the basis for most of the work of identifying organisms for the public, and are critical to research programs focusing on the taxonomy, systematics, and ecology of plants and animals.

Specimens and data associated with our collections are commonly used by research, administrative, and regulatory staff members and educators throughout the state of Illinois, by the general public, and by scientists worldwide—either by visiting our institution or through loan programs overseen by our curators and collections managers. Environmental and ecological data associated with specimens and the assimilation of that information into computer databases has been completed for a few collections and is in progress for others. Web-based, searchable databases for several collections also are available to the public. You are encouraged to visit all of our collections – either via the links from this page and our main INHS webpage, or by arranging to visit our collections in person through contact with our collections curators and managers.


physical address (office, INHS Annelida Collection):
206 Natural Resources Studies Annex,
1910 South Griffith Drive, Champaign

mailing address – U.S. Post only:
Mark J. Wetzel
Illinois Natural History Survey
Prairie Research Institute at the
University of Illinois at Urbana-Champaign
Forbes Natural History Bldg., MC-652
1816 South Oak Street
Champaign, Illinois 61820 USA

Delivery address – via commercial carriers:
(e.g., UPS, FEDEX, DHL)
Mail Room, Natural Resources Bldg.,
615 East Peabody Drive,
Champaign, Illinois 61820 USA

E-Mail: mjwetzel{AT}illinois.edu **

The picture at the top of this page was taken at Cascade Creek in Yosemite National Park, CA, during a preliminary survey of aquatic oligochaetes in May 2016.

* On July 1, 2008, the Illinois Natural History Survey – along with our sister agencies, the Illinois State Geological Survey, Illinois State Water Survey, and the Hazardous Waste Research Center (now the Illinois Sustainable Technology Center) transferred from the Illinois Department of Natural Resources into a new institute associated with the University of Illinois Urbana-Champaign — The Institute of Natural Resource Sustainability. In February 2010, the newly-formed Illinois State Archaeological Survey joined our Institute. On 11 May 2011, a new name for our group, the Prairie Research Institute at the University of Illinois Urbana-Champaign, was established.

** The ‘at’ [@] symbol in email addresses noted on this page has/have been replaced with ‘{AT}’ to repel the harvesting of email addresses by computer bots, information harvesters, trolls, and other entities created to capture information for illicit purposes [unwarranted, unwanted marketing, solicitations, non-pertinent invitations – almost all resulting in the compromise of your privacy]; please replace the ‘[AT]’ with ‘@’ before responding via email.

[page update: 06 July; 16,18,23Nov,31Dec2021 / 01jan, 29mar,24jul; 14Nov2022; 01Jan,11,12,17,19Apr; 04Aug2023; 01Jan, 14Feb2024; mjw]