TEST VERSION 2011 KEY TO THE EARTHWORMS OF BRITAIN AND IRELAND (Short test version) By Emma Sherlock (Natural History Museum, London)
ii EMMA SHERLOCK The accurate identification of specimens is a fundamental part of most forms of biological fieldwork. Although the 'popular' groups, such as wild flowers and butterflies, are wellserved by numerous aids to identification, many of the other groups are neglected. Unfortunately, even in those cases where guides are available, they may be inappropriate or inapplicable. The Field Studies Council's AIDGAP project (Aids to Identification in Difficult Groups of Animals and Plants) aims to provide clearly written and illustrated guides to enable the non-specialist to identify specimens in the field and lab. Although written and edited by specialists, all AIDGAP guides are extensively 'tested' before final publication. This ensures that the keys are subjected to extensive field tests by beginners and people with little or no experience in the groups being cove. Key to the earthworms of Britain and Ireland (short test version) By Emma Sherlock (Natural History Museum, London) This new AIDGAP key to Earthworms is being tested over the summer. Please try the key out and see how easy you find it to use. Feedback from testers is a critical part of the AIDGAP project, we value all your comments on the key s accuracy, ease of use etc, whether these are critical or otherwise. The author will revise the final version in light of this feedback; so all comments are potentially useful, no matter how trivial they may appear. In the final version many images will be in colour. Species notes and information on sampling and preservation will be included. Please either email your comments to publications@field-studies-council.org or post it them to: FSC Publications, The Annexe, Preston Montford, Shrewsbury, SY4 1DU Thank you for your support of the AIDGAP project, Dr Rebecca Farley-Brown
Key to the earthworms of Britain and Ireland (Test Version 2011) 1 HOW TO USE THIS KEY This key requires a low powe microscope, the worms to have been preserved (sampling and preservation guide to be included in full version of the key) and worms being completely submerged in a petridish in alcohol or water. When using this key, only the adult worms can be accurately identified to species. To tell if you have an adult worm or a juvenile you need to look for a clitellum or saddle, which is found on adult worms (see Fig. 1 and notes on page 4). If no clitellum (or any markings in this area) are present then the species can not be identified. If no clitellum is present you can only determine whether the worm has a tanylobic or epilobic head, however this can still be useful. If the saddle is not fully developed but some markings are visible in that area, then that could be a TP (see explanation on page 5) and this juvenile earthworm could still potentially be identifiable. You will need to be familiar with where on an earthworm s body the features highlighted below are to be found. If you are unsure please refer to the worm diagram (Fig 1), where the external anatomy is highlighted. DORSAL VIEW (back of worm) HEAD Prostomium Clitellum (saddle) Male pore Tubercular pubertatis (TP) Setae TAIL VENTRAL VIEW (underside closest to the ground) Figure 1. Diagram of the main external features of an adult earthworm. (Copyright L. Berridge)
2 EMMA SHERLOCK Tanylobic or Epilobic Head MAIN FEATURES EXPLAINED First locate the head end. The head end is the end that is closest to the male pore and clitellum (saddle). The head must be viewed dorsally (looking down from the top not from the underside). Often this will involve manipulating the worm to get it in a suitable position. Do not be too sca to hold the head down with forceps to get a good view. Use forceps to hold the head down Tanylobic head Lines meet 2nd segment Epilobic head Lines do not meet 2nd segment - Sometimes you need to look carefully this may look like a tanylobic head but the lines do not reach the 2nd segment. Sometimes some creases in the skin can also look like the furrows associated with a tanylobic head. If unsure key out in both sides of the key and check species pages carefully.
Counting Segments Key to the earthworms of Britain and Ireland (Test Version 2011) 3 This is something you will have to do a lot. To get started the first segments to count is the first full ring. Do not count the prostomium. Prostomium First segment Second segment Third Segment If you have already counted the 13 or 15 segments to the male pore, you do not need to count from the head again when counting segments to the clitellum and TP, just keep counting from that point. Some segments can have confusing furrows through them, if unsure look for the setae ridges to count segments. When counting segments on the clitellum be careful as often the segments become wider. Look carefully when counting.
4 EMMA SHERLOCK Male Pore Segment 16 Segment 14 In the Lumbricidae family this pore is found on segment 13 or 15. It can be very large encompassing the surrounding segements. Allolobophora chlorotica Segment 15 and main area of male pore Male pore Or it can even look a bit more like a slit than a pair of small lips. Eiseniella tetraedra Clitellum / Saddle The clitellum or saddle of an earthworm is important in reproduction. It is this which produces the mucus used in cocoon formation. The presence or absence of a clitellum denotes whether you have a juvenile or adult worm. Also the positioning of the saddle is very diagnostic when identifying worms. Juvenile worm as no clitellum present Adult worm as clitellum present Clitellum
Tubercular Pubertatis (TP) Key to the earthworms of Britain and Ireland (Test Version 2011) 5 Clitellum TP These are the markings, lumps, lines, swellings or sucker-like discs that are to be found on the lateral undersides of the clitellum. Aporrectodea longa TP Aporrectodea caliginosa TP Setae/chaetae Earthworms all have small setae on each segment. In the Lumbricidae family there are eight pairs per segment and whether these are widely or pai after the clitellum is sometimes used diagnostically. This can be the hardest character to see. Adjusting the microscope lighting and looking closer to the tail end of the worm can help. Widely pai Widely pai Closely pai Dendrobaena octaedra Eisenia veneta Lumbricus terrestris
6 EMMA SHERLOCK Key to the Earthworms of the UK and Ireland If identifying Earthworms for the first time please consult the section How to use this key (page 1) before getting started. 1) Is the head Tanylobic? (Please view worm dorsally for this character see page 2) Tanylobic... Go to Question 2 (Head-line of prostomium meets the 2nd segment) When colour is visible worms with tanylobic heads are. If in life your worm was not in colour you have gone wrong - check the head again. Epilobic Go to Question 5 (Head-line of prostomium does not meet the 2nd segment but stops short) 2) Does the clitellum (saddle) start on segment 29 or before? (Best to view worm dorsally for this character) YES... Go to Question 3 NO.... Go to Question 4 Head Male pore Clitellummn
Key to the earthworms of Britain and Ireland (Test Version 2011) 7 Read all 4 options 3) Does the TP fall on segments: (TP can be seen on lateral side of clitellum, best to view worm ventrally, see page 5) a) 27 or 28-31... Lumbricus rubellus TP b) 29-32... Lumbricus castaneus c) TP not visible (clitellum on segments 24 or 25 to 32 or 33)... Allolobophoridella eiseni Clitellum d) None of the above...... Go back to Question 1 (recheck the head and recount segments) Read all 3 options 4) Does the TP fall on segments: Clitellum a) 32 or 33 to 36 or 37... Lumbricus terrestris b) 34 to 36... Lumbricus friendi c) 35 to 38... Lumbricus festivus TP Lumbricus terrestris
8 EMMA SHERLOCK 5) Does the clitellum (saddle) start on segment 13? YES... Microscolex phosphoreus NO... Go to Question 6 If the clitellum starts on 15 you may have Sparganophilus tamesis. This is a very rare worm in the UK and might not now be present here. 6) Is the male pore on segment 13? YES... Eiseniella tetraedra NO... Go to Question 7 The male pore can sometimes be small and look like an extra furrow in the segment. TP 7) Does the clitellum (saddle) start on segment 30 or before? Clitellum starting on segment 30 or before...... Go to Question 8 Clitellum starting on or after segment 31...... Go to Question 21 8) Does the TP start on segment 31? TP starting on segment 31... Go to Question 9 NO... Go to Question 10
Key to the earthworms of Britain and Ireland (Test Version 2011) 9 9) Is the TP: a) 3 sucker like discs or 3 distinct lumps on 31, 33 and 35... Allolobophora chlorotica (In life a green or pink worm, stumpy in appearance) b) A thin band on segments 31-33 (can sometimes be an indistinct mound)... Dendrobaena octaedra (In life a small worm) c) 2 humps over the area of segments 31-33...... Apporectodea caliginosa (In life a grey/pinky worm, generally quite large. One rare morph can be very large and dark in colour.) If your worm has a TP just starting on 31 but the main area of the TP is 32-34 and it is a large worm with a dark head you are likely to have Aporrectodea longa. Please go to Question 12
10 EMMA SHERLOCK 10) Are the setae pai? Closely pai... Go to Question 11 Widely pai... Go to Question 17 TIP: When looking at setae it is best to look near the tail end of the worm as they often stand out better here. ALWAYS look after the saddle, never at the head end. 11) Does the TP start on or after segment 30? TP on or after 30... Go to Question 12 TP before 30... Go to Question 13 12) Does the TP fall on segments: 31/32 34... Aporrectodea longa 33-34... Aporrectodea limicola
Key to the earthworms of Britain and Ireland (Test Version 2011) 11 13) Does the TP start on segment 27 or 28? YES... Go to Question 14 NO... Go to Question 15 Check carefully here that the TP starts on these segments and NOT 29. 14) Does the TP have 2 humps or suckers on segments 28 and 30? YES... Allolobophora cupulifera So far only recorded in Ireland NOT in Britain NO... Eisenia fetida or E. andrei These are composting worms rarely found outside of the compost bin or areas rich in organic matter. 15) Does the TP fall on: Segments 29-31... Go to Question 16 Segments 29-30... Helodrilus oculatus CHECK 1: Occasionally Octolasion cynaeum could key out here. If the TP on your worm extends onto segment 33 or later, then go to Question 20. CHECK 2: Check the positioning of the clitellum. If the clitellum starts on segment 25 or 26 but the TP seems to be on 29-30 this is likely to be Aporrectodea rosea with a TP that is not fully formed. CHECK 3: If the TP is not visible and the clitellum falls on segments 26/27-33/34 you most probably have Murchieona muldal Helodrilus oculatus
12 EMMA SHERLOCK 16) Does the male pore encroach onto other segments? YES... Murchieona muldali NO... Aporrectodea rosea 17) Does the TP start before segment 30? Starting before segment 30... Go to Question 23 NO... Go to Question 18 18) Does the clitellum start on segments 26 or 27? Starting on segments 26 or 27... Go to Question 19 NO... Go to Question 20 19) Is the worm is over 5 cm long? YES... Dendrobaena veneta NO... Dendrobaena hortensis
Key to the earthworms of Britain and Ireland (Test Version 2011) 13 Read all 3 options 20) Does the TP span segments: a. 30-32........ Dendrobaena attemsi b. 29 or 30-33 or 34... Octolasion cynaeum c. 30-35... Octolasion lacteum D. attemsi is a small relatively rare worm O. cynaeum is a larger bluey grey worm with a clitellum starting on segment 29 O. lacteum has a clitellum starting on segment 30. The TP extends the whole length of the clitellum. 21) Does the TP start before or on segment 35? TP starting on segment 35 or before...... Go to Question 22 TP starting on segment 36 or after...... Aporrectodea icterica If no TP is visible at all it may still be A. icterica as it can be very hard to see. Bands extend the whole length of the clitellum. 22) Does the TP start on: 32 or 33... Satchellius mammalis 35... Dendrobaena pygmaea These are both small worms. Maximum size 45 mm.
14 EMMA SHERLOCK 23) Is the TP either absent or when present ends on segment 30? YES... Dendrodrilus rubidus NO... Octolasion cynaeum D. rubidus is a worm in life which has a TP consisting of a band or swelling on segments 28 or usually 29-30. O. cyneaum is a grey or bluey grey colour in life. Its TP is a band on segments 29 usually 30 or through to 33 or usually 34.
Quick earthworm comparison chart 15 Species Allolobophora chlorotica Allolobophora cupulifera Allolobohoridella eiseni Aporrectodea caliginosa Aporrectodea icterica Aporrectodea limicola Aporrectodea longa Aporrectodea rosea Dendrobaena attemsi Dendrobaena hortensis Dendrobaena pygmaea Dendrobaena octaedra Dendrobaena veneta Dendrodrilus rubidus Eisenia fetida Eiseniella tetraedra Helodrilus oculatus Lumbricus castaneus Lumbricus festivus Lumbricus friendi Lumbricus rubellus Lumbricus terrestris Microscolex phosphoreus Murchieona muldali Octolasion cyneum Octolasion lacteum Satchellius mammalis Head shape tanylobous tanylobous tanylobous tanylobous tanylobous tanylobous Setae widely widely widely widely widely widely Different patterning widely after saddle widely after saddle widely Colour in life (can be variable) pink or green usually pinky grey, occasionally large worm with very deep head resembling longa. usually grey with striped appearance when stretched browny colour grey can be phosphorescent usually light in colour variable bluey grey grey Clitellum (segments) 28-29 to 37 25-26 to 32 24 to 32-33 variable starting 25-29 ending on 34 or 35 usually grey 33-34 to 42-43 very dark head 28-29 to 35-36 almost black pink 27-28 to 35-36 rosey to looses 25-26 to 32-33 colour very quickly can be fla when preserved 28-29 to 34 dish 26-27 to 33 32-33 to 37-38 24-26 to 32-24 22-23 to 26-27 21-22 to 32 27-28 to 33-34 33-34 to 40 32-33 to 37 27-28 to 32 32-37 13 to 17 26-27 to 33-34 29 to 34 30 to 35 31 to 36 TP segments 31,33,35 28, 30 35-36 to 42-43 33-34 31 usually 32-34 29-31 30-32 30 to 31-32 absent or on 35-37 31-33 27-28 to 34 30 to 31-32 26-27 to 32-33 28-29 to 30 25-27 to 31-32 27-28 to 30-31 22-23 to 25 29 to 30 29 to 33 35 to 38 34 to 36 28 to 31 32-33 to 36-37 N/A 29 to 31, sometimes absent 29-30 to 33-34 30 to 35 33 to 34 TP shape NONE N/A 31-33 (can 2 humps start first half of 30) Sucker-like discs or 3 distinct mounds 2 sucker like discs or 2 distinct mounds long thin band (can be hard to differentiate from the edge of the clitellum 2 humps band band swelling swelling ridge or swelling usually a defined line otherwise a swelling swelling swelling thin bands band swelling band band thin ridge broad band ridge N/A band band swelling often looking like a semi-circle
Key to the earthworms of Britain and Ireland (short test version) This new AIDGAP key to Earthworms is being tested over the summer. Please try the key out and see how easy you find it to use. Feedback from testers is a critical part of the AIDGAP project. We value all your comments on the keys accuracy, ease of use etc, whether these are critical or otherwise. The author will revise the final version in light of this feedback; so all comments are potentially useful, no matter how trivial they may appear. Please either email your comments to publications@field-studies-council.org or complete the form and post it to: FSC Publications, The Annexe, Preston Montford, Shrewsbury, SY4 1DU Thank you for your support of the AIDGAP project. AIDGAP TEST VERSION - Key to earthworms of Britain and Ireland 1 What type of identification guides have you used before? 2 - Did you find this Guide easy to use? YES / NO 2 Where you confident that your identifications were correct? YES / NO (please comment) 3 Did you find any parts of the guide/keys difficult or misleading? YES / NO (please comment) 4 Were there sufficient illustrations? YES / NO (please comment) 5 Are there any changes you would like to see made before final publication? (please comment) 6 Is there any additional information that you would like to see included? 7 - Any additional comments? Name: Please return by 1st AUGUST 2011