Envlronment Canada Environnement Canada
Fisheries Service des pêches .1 and Marine Service et des sciences de la mer
L .' 1 '; ( 1 l r A Guide for the Identification of Two Subfamil ies of Larval Chironomidae: ,1"'--- The Chironominae and Tanypodlnae . : - - . ) / Found .in Benthic Studies Jin the / r~---.-_ c L___ r - - '" - .Ç"'''''-. Winnipeg River in the Vicinity ot Pine Falls, Manitoba in 1971 and 1972
by P. L. Stewart J.S. Loch
Technical Report Series No. CEN/T-73-12
Resource Management Branch Central Region DEPARTMÈNT OF THE ENViRONMENT FISHERIES AND MARINE SERViCE
Fisheries Operations Directorate
Central Region
Technical Reports Series No. CEN/T-73-12
A guide for the identification of two subfami lies of larva l
Chironomidae~ the Chironominae and Tanypodinae found in benthic studies in the Winnipeg Riv~r in the vicinity of
Pine Falls, Manitoba, in 1971 and 1972. by: P.L. Stewart qnd J.S. Loch
ERRATA
Page13: The caption for Figure 5A should read:
Mentum and ventromental plates..•...
instead of: submentum and ventromental plates..•..
Page 14: The caption for Figure 5B should read:
Mentum and ventromental plates .
instead of: submentum and ventromental plates.... DEPARTMENT OF THE ENVIRONMENT
FISHERIES AND MARINE SERVICE
Fisheries Operations Directorate
Central Region
Technical Report Series No: CEN/T-73-12
A GUIDE FOR THE IDENTIFICATION OF IWO SUBF.AMILIES OF LARVM.... CHIRONOMIDAE: THE CHIRONOMINAE AND TANYPODINAE FOUND IN BENTHIC STUDIES IN THE WINNIPEG RIVER IN THE vrCINITY OF PINE FM....LS, MANITOBA IN 1971 and 1972
by
P. L. Stewart and J. S. Loch
Resource Management Branch Fisheries Operations Directorate Central Region, Winnipeg
November 1973 i
ABSTRACT
Identifying characteristics of the genera of two subfamilies of larvae of the midge family, C~onomldae (Vlpt~a), the C~ono mlnae and the Tanypodlnae, are presented with illustrations for the purpose of simplifying identification of these two groups by novice and more experienced personnel involved in assessment of benthic faunal composition. ii
ACKNOWLEDGMENTS
O. Saether, A~ Hamilton and W. Warwick of the Freshwater Institute (Winnipeg, Manitoba) verified identification of sorne of the specimens used in this guide. o. Saether read and criticized the manuscript. W. Warwick gave advice on nomenclature and helped clarify obscure differences between sorne genera. Many of the photographs and illustrations were taken from specimen slides in the Freshwater Institute collection. iii
TABLE OF CONTENTS
Page
Abstract ••••••• ...... III . i AcknowLedgments .. ii List of Figures .. iv Introduction .. 1 Notes on use of guide •••••••••••••••.•••.•••••••••••.•• 3 Note on terminology used ••••••••••••••••••••••••••••.••• 5 Subfamily Characteristics ••.•••• 6 Generic Characteristics ••••••••••••••••••••••••••••.•••••• 17
Refererices D ' .. 46 iv
LIST OF FIGURES
Page
Fig. 1 Head capsule characteristics of Chironomus 9
Fig. 2 Antennal types found in larvae of t~e tribe Chironomini ...•...•.•.•.•.•.•...... •...... 10
Fig. 3 Head capsule characteristics of Micropsectra Il
Fig. 4 Head capsule characteristics of Procladius 12
Fig. 5 Mentum and ventromental plates of larval Chironomini ;...... 13, 14
Fig. 6 Antennae and mental structures of several
Tanytarsini ',' ~ ...•...... Il •••• " 15
Fig. 7 Lf.guLa and pavaglossa of the larvae of several Tanypodinae .•...•.•..•..•.•.•.•.•.•...•.•.•...... 16
Fig. 8 Chironomus-larval head capsule characters 20
Fig. 9 Glyptotendipes-larval head capsule ~haracters 21
Fig. 10 Dicrotendipes-larval head capsule characters 22
Fig. 11 Polypedilum (Pentapedilum)-larval head capsule 'chat-acters ....•.•..•.•.....•...... 23
Fig. 12 Polypedilum (Fallax)-larval head capsule characters ...... •..•....•...... 24
Fig. 13 Microtendipes-larval head capsule characters 25
Fig. 14 Paratendipes-larval head capsule characters 26
Fig. 15 Cryptochironomus-larval head capsule characters ..... 27
Fig. 16 Demicryptochironomus-larval head capsule characters. 28
Fig. 17 Head capsule characters of Endochironomus, Phaenopsectra (Phaenopsectra) and Phaenopsectra (Tribelos) ...•.... 30
Fig. 18 Endochironomus-larval head capsule characters 31 v
Page
Fig. 19 Stictochironomus-1arva1 head capsule characters..... 32
Fig. 20 Parac1adopelma-1arval head capsule characters...... 33
Fig. 21 CpYptotendipes-1arval head capsule characters...... 34
Fig. 22 Cryptocladope1ma-larval head capsule charactets..... 35
Fig. 23 Micropsectra-1arval head capsule characters.,...... 36
Fig. 24 Tanytarsus-larval head capsule characters...... 37
Fig. 25 Stenochironomus-larval head capsule characters...... 38
Fig. 26 Parachironomus-larval head capsule characters...... 39
Fig. 27 Ablabesmyia-larval head capsule characters...... 40
Fig. 28 Larval head capsule characters of Coelotanypus and Clinotanypus...... 41
Fig. 29 Thienemannemyia group -larval head capsule
characters ".. 0 • • • • • • • • • 42
Fig. 30 Procladius-larval head capsule characters...... 43
Fig. 31 Tanypus-larva1 head capsule characters...... 44
Fj,g. 32 Psectrotanypus-larval head capsule characters...... 45 l
INTRODUCTION
Larval Chironomidae (Diptera) are one of the more important groups of organisms to be encountered in most benthic studies. The' group has a cosmopolitan occurrence, occupying a wide range of benthic habitat, in streams, lakes, pools, estuaries, and subject toa variety of environmental conditions. In addition, the Chironomids make a significant contribution to the biomass and nûmbers in benthic communities and can probably be considered the most frequently encountered inverte brates in fresh water studies.
The plasticity of the Chironomidae as a group in their range of habitat is reflected in the diversity of .fo rm found in the group.
The Chironomidae encompasses more genera and more species than any other insect group -- new species are discovered almostas fast as unexplored geographical areas are opened to the Chironomid taxonomist.
Recent interest in benthic studies in assessing the effects of man on his aquatic environment (pollution, construction and mechanical effects, eutrophication etc. in lakes and streams) has led to a need for a more precise assessment of benthic systems in terms of what organisms are contained in them and how the organisms will react ta environmental changes caused by man. The predominance of Chironomidae in freshwater benthic systems makes them an ideal and important group ta deal with inthis regard.
In such studies, identification of larval Chironomidae ta at least the generic level is almoqt certainly involved. This may pose problems since accurate identification may involve as much or more time and effort as the interpretive effort, and often requires considerable 2
familiarity with the literature dealing with Chironomid taxonomy.
The purpose of this report is ta assist in the identification of sorne larval Chironomids. It is designed primarily ta help persans starting out in Chironomid identification, but also ta act as a reference for persons with more experience. Included are the useful generic characters of two Chironomid subfamilies, the Chironominae and the
Tanypodinae. There are four additional subfaII)ilies (Orthocladiinae,
Podonominae, Telmatogetoninae and Diarnesinae) which form a significant part of the Chironomidae but which are not dealt with here. Hopefully identification experience gained with these two subfamilies will facilitate reference work on the other subfamilies.
Illustrations for the guide were taken largely from samples taken in Fisheries Service benthic studies on the Winnipeg River in the '11, summers of 1971 and 1972. Illustrations of additional genera were taken from specimen slides in the Fisheries Research Board, Freshwater
Institute (Winnipeg, Manitoba) collection. Host genera in the subfamily
Chironominae are included in the guide, although not aIl are illustrated.
The subfamily Tanypodinae is not as weIl represented but aIl cornmon genera are included.
Most of the characteristics presented her~ have been taken from available literature sources and from a provisional key by
Hamilton and Saether at the Freshwater Institute in Winnipeg. Additional characteristics came from persona.l communication with A. Hamilton,
O. Saetherand W. Warwick at the Freshwater Institute. The characteri- stics presented were felt ta be the most useful in identification of specimens of the level of preparation likely ta be encountered in an average benthic operation. 3
NOTES ON USE OF GUIDE
The guide is divided into two sections, one dealing with subfamily and tribe characters, the other with generic characters.
The section on subfamily and tribe characters contains a description of the subfamilies Chironominae and Tanypodinae, and of the two tribes of the Chironominae, the Chironomini and Tanytarsini.
This description is followed by several figures (Figures 1 - 4) illustrating the subfamily and tribe differences. In addition,
Figures 5 - 7 give an overview of important features in genera of the two subfamilies.
The most useful approach 'in using the guide is to become familiar with the subfamilyand tribe characters by way of the illustra tions (Figures 1 - 4), while referring to the particular specimen to be identified. Figures 5 - 7 then provide a rapid means of finding a genus which is at least similar to the one being examined.
The section on generic characters contains illustrations and accounts of the characteristics of many of the genera of the Chironominae and the Tanypodinae. Each page contains illustrations, a listing of several generic characteristics, and a photograph of one genus, except in special cases. The illustration is the most important feature of each page--the text serves to reinforce the illustration and to clarify differences in genera. The photograph is included to give an indica tion of head capsule shape;
The best procedure in using this part of the guide for identification is to leaf through the guide until a suitable illustration is 4
found--then to verify the identification by way of the text and possib1y by the photogr~ph.
A short 1ist of usefu1 references is given at the end of the report. Those.with asterisks contain good i11ustrations--doub1e asterisks denote a recommended-reference. It is advised that as many of the references as possible be used and that simple keys be used with discretion.
A difficu1ty in going to the 1iterature is dea1ing with the variety of names that have been assigned by different authors at different times to the same taxonomie units. This prob1em may be overcome to a certain extent by fo11owing Ha~i1ton, Saether and Oliver (1969). The report conso1idates the nomenclature used by authors of important works in C~onomid taxonomy and assigns themto a common system of nomenclature based on that used by
European workers. The nomenclature used in this guide fo11ows
Hamilton, Saether and Oliver (1969). 5
NOTE ON TERMINOLOGY ASSOCIATED WITH HEAD CAPSULE CHARACTERS
Head capsule terminology used in this guidefollows
Saether (1971b).
Synonyms for the various head capsule parts likely to be encountered in the literature are also found in Saether's paper.
The arrangement and position of the head capsule characters
of larvae of the two subfamilies of Chironomidae considered here are
shown in Figures 1 - 1+. 6
SUBFAMILY CHARACTERS 7
Subfami1y Chironominae
The 1arvae of this subfami1y may be distinguished from other subfami1ies by the presence of an en1arged and usua11y heavi1y pigmented mentum and the presence of striated ventromenta1 plates (Fig. 1).
The ventromenta1 plates may be coarsely or fine1y striated or may lack striations entire1y. Patterns of striation are usua1ly characteristic of certain genera.
The Chironominae is divided into two tribes, the Tanytarsini and the Chironomini(Fig. 2). Genera in the tribe Tanytarsinihave elongate antennae with conspicuous Lauterborne organs at the apices of the second and third antenna1 segments (Fig. 3). Antennae are generally located on a distinct head protuberance, the antennal tubercle. Ventro mental plates are usually elongate and slightly rectangular, often meeting at or near the head capsule midline. Teeth in the mentum are usually quite uniform in size.
Most genera of the tribe Chironomini have fan-shaped ventro mental plates which do not meet at the head capsule midline. Antennae are usually short and are not particu1ar1y evident when the head is viewed who1e. The mentum is genera11y dark1y pigmented, usua1ly with tooth height variation.
Subfami1y Tanypodinae
This subfami1y is characterized by an absence of ventromental plates and the presence of a fork-shaped 1igu1a (Fig. 4) which may be
1ight in co1or or dark1y pigmented. A mentum is not evident in most 8
genera but is evident in some (Procladius, Psectrotanypus) as a comb-like set of dorsomental teéth located anterior to the ligula
The antennae are elongate and retractile, that Ls , they may be wi thdrawn into a sheath in the head capsule•.
Subfamily Orthocladinae
Orthoclads have darkly-pigmented menta similar to those of the Chironominae. The ventromental plates of the Orthoclads are, however, usually much reduced and unstriated. The apparent absence of ventromental plates in specimens with distinct menta is a rough criterion for the identification of the Orthocladinae. 9
Figurel. Ventral view of the head capsule of. Chironomus (Subfamily Chironominae, Tribe Chironomini). an-antenna; e-eyespot; ep-epipharyngeai pecten; m-mentum; mn-mandible; mx-maxillary palp; ~ventromental plates. 10
A
B c
o
Figure 2. A, B, and C ... antenna1 types found in 1arvae of the tribe Chironomini. (A) Microtendipes seven-segmented antenna. ab-antennal b1ade; 1 1auterborne organs. (B) Stictochironomus.; note six segments. (C) Po1ypedi1um- five-segmented an tenna.(D) Location of epipharyngea1 pecten in Phaen opsectra, Tribe Chironomini. Il
Figure 3. Head capsule characters of Micropsectra (Sub family Chironominae, Tribe Tanytarsini ). an-antenna; at antennal tubercle; e-eyespot; la-lauterborne organ; s-spine on antennal tubercle; m~mentum ; vm-ventromental plate. 12
Figure 4. Head capsule characters of Procladius (8ub family Tanypodinae). an-antenna; dm-dorsomental teeth; l-ligula ; mn-mandible; mx-maxillary palp; p-paraglossa. 13
I~
8 J
c K
L
E
F
G ~~ 0 ...
P ,,,-\Iv- ..
Figure SA. Submentum and ventromental plates of larval Chironomini. CA) Chironomus (B) Glyptotendipes CC) Dicroteridipes CD) Polypedilum pentapedilutn CE) Endochiroriomus CF) Microtendipes CG) Polypedilum (Fallax) CH) Polypediluml(Pentapedilum). (1) Stenochironomus (J) J!:ndochironomus CK) Stictochironomus' CL) Paratendipes CM) Paratendipes (N) Pseudo chironomus (0) Cryptochir"dnomus CP) Demicryptochironomus 14
T
v _\\\11/1/11/0 /:
Figure SB. Submentum and ventromental plates of La'rvaL Chironomini(continued from Fig. SA ). (Q) Paracladopelma (R)Cryptotendipes (S) Crypto cladopelma (T) Parachironomus (U) Xenochironomus CV) Omisus (W) Goeldichironomus (X) Paralauterborniella CY) Xenochironomus (Z) Xenochironomus CA')Pagastie11a 15
A 8 D
I~
F
H G
l
Figure 6. Antennae and J!l~nt:.a of severa1 Tanytarsini. (A) Stempe11ina (B) Stempe11ina (After Johannsen, 1937) (C) Rheotanytarsus (after Johannsen , 1937) (D) Zavre1ia (E) C1adotanytarsus (F) Zavre1ia (G) Stempe11ina (H) Tanytarsus (1) C1adotanytarsus. 16
E 1tH
B
r c
J
D )
Figure 7. Ligula and paraglossa of the larvae of several genera of Tanypodinae. (A) Procladius (B and C) Ablabesmyia (D) Nilotanypus (E) Clado tanytarsus (F) Coelotanypus (G) Psectrotanypus (H) Clin~us (1) Tanypus (J) Thienemannemyia group. 17
GENE:R,IC CHARACTERS 18
LIST OF GENERA
Page
Chironomus Il li Il Il Il Il '•• Il Il Il Il Il ..... Il • Il Il Il Il Il Il Il Il Il Il Il Il Il • Il Il Il Il CI Il Il Il' Il Il Il Il Il Il Il _ .. ' Il Il Il Il Il Il 20
Gl.yptotendipeE; ' ...... ••...... 21
Dicrotendipes ...... •...... 22
Po l.ypedi Lum (Peniiapedi. Lum) 0 23
Pol.ypedil.wn (Pal.Lax) •.•.•••.••.•.•...•..•••••.• 0 ••••••••••••••• , •• 24
Il.~ tâicroiendipee .Il.11 Il Il' Il Il Il Il Il Il Il Il Il Il Il Il Il Il • Il Il Il Il Il Il Il Il Il, Il Il Il Il Il Il Il Il Il Il, Il Il Il Il Il Il' Il Il. Il Il' Il Il 25
Paraiendipee Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il, Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il Il, Il Il, Il' Il Il Il Il .: Il''' Il 26
Cryptochironomus 0 •••••••• o••••••• 0 • 0 • 0 .0 ••••• 0 ••• 27
~ Demicryptochironomus 0 •••••••••••••••••••••••••• •••••• 28 ,
Endochironomus o•••••••••••••••••••••••• 29,30,31 1 0 Phaenopeectira (Tribel.08J ••••••••••••••••••••••••••••••••••••••••• 29,30
Phaenopeeciira (Phaenopeeatma) ••••.••.••..• .- •.••••••••••. 0 ••••••••• 29,30
Stictochironomus ...... •...... 32
Parael.adope lma ..••...... o. .• 33
Cy'yptotendipes '. . • ...... 34
Cryptocl.adopel.ma 35
~ tâioropeeotara ...•.•••.....•...... 0 ••••••••• o ••• •••••••••••••••••••• 36
Tanytarsus 0 ••••••••••••••••••••••••••••••••••• 37 0
Stenochironomus 38
Paraehi.ronomue ...... •...... 39
Abl.abesmyia .. Il Il Il Il Il Il Il Il Il Il Il .. ,II 'Ill Il • Il Il Il Il Il Il Il Il Il • Il Il Il Il CI Il Il Il Il Il- (1 'II Il Il Il Il 1:1 Il Il Il Il Il Il • CI Il 40
CoeLotanypus 41 19
LIST OF GENERA (continued) Page
Clinotanypus.... 41
Thienemannemyia ••••••••••••••••••••••• e ••••••••• o •••••••••• e •• 42
Prool.adùue O •••••• II •••••••••••••••••••••• IIJ.·...... 43
Tanypus . 44
Psectrotanypus 0 •••• CI Il ••••••• 0 •••••• 17 •••• Il • • • • • • • • • • •• 45 CHIRDNDMINAE 20 TRIBE CHIRDNDMINI ChironomuB
Chlronomus - mentum has 13 teeth. Median tooth 15 slightly reduced and trlfld. - eplpharyngeal pecten has more than seven long teeth - antennae are five-segmentedj basal segment of antenna 15
notlceably wlder at base than at apex - usually has a pair of ventral abdominal gllls on the eleventh
body segment (see fig. 9D) - premandibles are bifld Similar genera: Kiefferulus - the premandibles have six teeth. Einfeldia - the epipharyngeal pecten has seven or fewer
t e e t h ; ventral abdominal gills are absent.
Figure 8. Chironomus. '(A) mentum and ventromental plate (B) epipharyngial pecten (C) antenna (D) mandible CHIRONOMlNAE 21 TRIBE CHIRONOMINI
GZyptotendipeB
Glyptotendlpes
flve-segmented antennae
ventromental plates usually longer than two tlmes the wldth
eplpharyngeal pecten with more than 7 splnous projections (Figure 9c) often has ventral gllls on eleventh body segment (FI gure 9D)
A
c ~~
Figure 9. Glyptotendipes. (A)mentum and ventromental'plate (B) antenna (C) epipharyngeal pecten (D) anal section. Ventral gills(vg)on eleventh body aegment , CHIRONOMINAE 22 TRIBE CRIRONOMINI Diarotendipes
Oicrotendipes five-segmented antennae
ventromental plates 1ess than two times as long as wide,
fan-shaped. Anterior margin crenulated as in Fig. lOB
body sègment 11 never has ventral gi11s epipharyngea1 pecten with 5-7 blunt, squarish, teeth (F i g. 100)
Figure 10. Dicrotendipes. (A) mentum and ventromental plate (B) ventromental plate (crenulated anterior margin) (C) antenna -(D) epipharyngeal pecten (E) anal section showing absence of ventral gills on eleventh body segment CHIRONOMINAE
23 TRIBE CHIRONOMINI
Polqjpedi/lum (Peniapedi lum)
Po1ypedi lum (Pentapedi l urn)
-five-segmented antenna
-epipharyngeal pecten in three sections, each with three or more
teeth
-antennal segments 2 to 4 are about the same length
-first lateral teeth of mentum are much smal1er than adjacent
teeth (Figure 11A) or are just sl ightly shorter than adjacent
median and 1atera1 teeth (Figure IlE).
1 /1 ~F \iiI H ) J
Figure Il. Polypedilum CPentapedilum) CA and E) mentum and ventromental plate CB) epipharyngeal pecten CC and G) mandibles CD and H) ant- ennae CF) premandible. CHIRONOMINAE 24 TRIBE CHIRONOMINI PolypediZwn (Pal/la»)
Pol YPe di 1um(Fa 11 ax) five antennal segments ring organ is usually present on the proximal flfth of
the basal antennal segment epipharyngeal pecten has three sections, each with three
or more teeth the median six teeth of the mentum are almost identi- cal in size, and slope gradual1y to its lateral edge
antennal ratio of about 55:18:8:8:3 (Johannson, 1937a
Figure 12. Polypedilum (Fallax} (A) antenna (B) rnaxillary palp (C) mandible (D) mentum and ventromental plate CHIRONOMINAE
25 TRIBE CHIRONOMINI Microtendipes
Microtendipes
antennae six·segmentedj Lauterborne organs present at the
apices of antennal segments 2 and 3 (Fig. 2A, 13A)
total tooth number on mentum is 14. Two median
teeth 1 ight-colou,ed
smal1 f l r s t 1ateral teeth of mentum may appear fused to
second laterals
epipharyngea1 pecten composed of three con~inuous sections
with irregu1ar teeth (Fig. 13e)
Simi l a r genera: The mentum of Polypedilum is similar to that of Microtendipes
but the median teeth are heavi ly pigmented in the former.
Antennae are five-segmented.
A ~c
Figure 13. Microtendipes. CA) antenna CB) mentum and ventromenta1 plates CC) epipharyngea1 pecten CHIRONOMINAE 26 TRIBE CHIRONOMINI POX'atendipes
Paratendipes antennae are six-segmented with lauterborne organs at
the apices of segments 2 and 3 (Figure 14D) medial portion of the rnentum is concave with four
light-coloured median teeth (Figure 14A, E) mehtum has sixteen teeth
Figure 14. Paratendipes. CA and E)·mentum and ventromental plates CB) mandible CC) ep1pharyngeal pecten CD) antenna CHIRONOMINAE
27 TRIBE CHIRONDMINI Cryptoahironomus
Cryptochironomus m€dian tooth of mentum is wide and light-coloured. Flanks of median tooth and the remaining teeth of mentum are heavily pigmented (Figure 15B)
number of pigmented teeth in the mentum (excluding the pigmented margln of the medlan tooth) Is ten antennae are flve-segmented
Simllar genera: Demlcryptochlronomus - medlan tooth of mentum wide and llght-coloured; seven pairs of plgmented teethj antennae seven-segmented
~A
o D
Figure 15. Cryptochironomus. (A) antenna (B) mentum and ventromental plates (C) premandible (D) mandible. CHIRONOMINAE
TRIBE CHIRONOMINI 28 Demiaryptoahironomus
Demicryptochironomus median tooth of mentum very wide and light-coloured;
seven pairs of pigmented teeth not including pigmented
flank of the median tooth (Fig. 16B)
antennae seven-segmented with blade originating at the
apex of the third antennal segment
premandible trifid (Fig. 16e)
\\D/D F \?C n )\ /[jJ" pp
Figure 16. Demicryptochironomus. CA) antenna CB)- mentum and ventromental plate CC) premandib1e CD) maxi11ary pa1p (E) mandtb1e CF) anal section showing posterior pro1egsCpp), anal tubules Ca), proceri Cpr) and setae Cs} on procerci. CHIRONOMINAE 2.9 TRIBE CHIRONOMINI Phaenopseatra (Phaenopseatra) Phaenopseatra (TribeZos) Endoahironomus
Endochl ronomus, Phaenopsectra (Phaenopsectra) and Phaenopsectra (Tribelos)' have menta which are slml lar ln appearance - and as a result no positive separation of the three may be made on the basls of the mentum appearance a lone . The three can be separated somewhat by tooth pattern on -eplpharvn geaI pecten (Fig 2D), by antennal types and by striations on and the shape of the ventromental plates. The basic dlfferences are summarlzed ln Figure 17. It should be noted that Identification of these three groups has not been worked out completely via rearlng. This tentative scheme was suggested by Warwick (personal communication).
Phaenopsectra (Trlbelos) - five segmented antennae wlth antennal blade longer th an the length
of the terminal four segments. - epipharyngeal pecten in three pieces, each of which has teeth showlng ln several planes (versus the fIat, palmate situation in
P. (Phaenopsect ra) (Fig. 171) - has two fields of striations on the ventromental plates which are shlfted to the posterior of the plates (Fig. 17J). Ventromental plates are roughly triangular.
Phaenopsectra (Phaenopsectra)
f lve segmented entenna ; antenrra l blade shorter than or nearly the same length as the terminal four segments. - eplpharyngeal pecten ln three pleces, each of whlch is palmate and bears 3 - 4 teeth (See Fig. 17F) - has a local Ized patch of striations medlally on the ventromental plates. Ventromental plates are roughly trlangular.
Endoch 1ronomus - five-segmented antenna with antennal blade roughly the same length as the remaining four antennal segments. epipharyngeal pecten is a continuous row with teeth in several fi 1es (Fi g. l.7D) - ventromental plates have two full rows of striations located towards the anterior of the plates. (Fig. 17E) Ventromental plates are more elongate than in Phaenopsectra and rnay have their outer edge rounded. 30
A
c o \\\\\\1\ \\111l111I11 r/If/IIII!f E \\\~\\\ III 1 ~~\\\\\ \\\\\~{I{' I"
F ·G
H l J
Figure 17. Larval head capsule characters of Endochironomus, Phaenopsectra (Phaenopsectra) and Phaenopsectra (Tribelos). (A) mandible of r; (Phaenopsectra) (B) generalized mentum of the three types. (C) antennal type of Endochironomus and r. (Phaenopsectra). Note antennal blade length. (D and E) epipharyngeal pecten and ventromental plate of Endochironomus. (F and G) epipharyngeal pecten and ventromental plate of Phaenopsectra (Phaenopsectra). (H) Antenna of f. (Tribelos). Note antennal blade length. (1 and J) epipharyngeal pecten and ventro mental plate of P. (Tribelos). Illustrations of the epipharyngeal pectens from Wa~ick (personal communication). CHIRONOMINAE 31 TRIBE CHIRONOMINI Endoahironomus
Endochironomus in part
three median teeth of mentum similar in size. Median
tooth may be 51 ightly reduced
antenna five-segmented
Simi lar genera: Stictochi ronomus Median tooth of mentum much reduced. Antenna six-segmented.
Figure 18. Endochironomus. (A) ~entum and ventromental plate (B) antenna (C) mandible (D) maxillary palp CHIRDNDMINAE 32 TRIBE CHIRDNDMINI stiatoahironomUs
Stictochironomus
two median teeth of mentum distinctly smaller than first
laterals (Fig. 19 A, D). Fourteen dark-coloured teeth
in ail. Mentum may have an odd number of teeth wi th
a minute median tooth.
antennae six-segmented. Lauterborne organs alternate
at the apices of antennal segments 2 and 3 (Figure 2 B,
19B) ventromental plates are unstrlated Simllar genera: Phaenopsectra (Tr Ibe los ) , f.. (Phaenopsectra) and Endochi ronomus have siml Jar menta but have five-segmented antennae and distinct striations on the ventromental plates.
A /1 il,n )\ 1 B ",.---..
D
Figure 19. Stictochironomus. (A and D) mentum and ventromental plates (B) antenna (C) mandible CHIRDNDMINAE
33 TRIBE CHIRDNDMINI ParaaZadopeZma
Parac1adopelma
antennae five-segmented
antennal blade may originate from the midd1e of second
antenna1 segment (Fig. 20 B)
median tooth of mentum is wide and l ight-coloured and may be cleft
into four short, flat-topped teeth (Fig. 20A)
thi rd antenna1 segme~t minute (Fig. 20B)
Similar genera: Harnischia. Mentum simi1ar in appearance to Paracladopelma. Second and th i rd antennal segments about the same length. (see
Saether , 1971a)
o E
Figure 20. Paracladopelrna. (A) rnenturn and ventrornental plates (B) antenna (after Roback, 1957) ce) prernandible (D) antenna of Harnischia. Note length of third segment. (E) rnenturn and ventrornental plate of Harnischia. (after Saether,1971a) CHIRONOMINAE
34 TRIBE CHIRONOMINI
Cryptotendipes
Cryptotendlpes antennae flve-segmented mentum has a large medlan tooth which is not cleft
medlally but may have s ll qh t lateral Indentations.
extreme lateral teeth of mentum are slightly enlargedj teeth dark-coloured
Figure 21. Cryptotendipes. CA) mentum and ventromental plates CB) antenna CC) premandib1e CD) mandib1e. CHIRONOMINAE 35 TRIBE CHIRONOMINI CryptoaZadopeZma
Cryptocladopelma antennae five-segmented
sorne lateral teeth of the mentum are distinctly enlarged'
(Fig. 22A, D) mentum with singly-cleft median tooth. AIl teeth of mentum are clark
~ Il
~c D
Figure 22. Cryptocladopelma. (A and D) mentum and ventromental plate (B) antenna (C) mandible. CRIRDNDMINAE
36 TRIBE TANYTAR8INI
Microspectra Micropsectra elongate, curved, first antennal segment (Fig. 23A) second antennal segment elongate, about as long as remaining three antennal segments antenna on a prominent antennal tubercle which has a projection (" s pu r") on its Inner apex (Fig. 23 G, H). Tanytarsus has no such spur. tlllo Lauterborne organs on long pedlcels orlglnatlng from the apex of the second antennal segment J uncture of each procercus and its setae appears as a dark ring (Fig. 23 1). Found as weIl in Tanytarsus. ventromental plates elongate and nearly touch at head capsule midline (Fig. 25A, a)
Simllar genera: Micropsectra - Tanytarsus never has any sort of spur at the apex of the antennal tubercle
G
Figure 23. Micropsectra. (A) antenna (B) Lauterborne 'organ on antenna (C,D, E and F ) mentum and ventromental plates (G and H) spines on antennal tubercles (1) anal section showing setae onpr~cerci and spines on posterior prolegs CHIRDNDMINAE
37 TRIBE TANYTARSINI Tanytarsus
Tanytarsus
antenna on a prominent antennal tubercle
first antennal segment long and curved
two Lauterborne organs on long petioles originating at the
apex of the second antennal segment
second antennal segment about equal in length to length
of remaining antennal segments
8
Figure 24. Tanytarsus. (A and B) mentum and ventromeBtal plates (C) antenna- note tubercle and lauterborne organs. CHIRONOMINAE
38 TRIBE CHIRONOMINI stenoohieonomue
Stenochlronomus antennae flve-segmentecl
anterior margin of mentum concave with ten clark teeth (Fig. 25, A, C)
- antennal ratio 13:4:2:2: 1 (Johannsen 1937a
A
otT cr 7E c )(1
Figure 25. Stenochironomus. CA and C)lmentum and ventromental plates CB) mand- ible CD) spine on posterlor proleg Cafter Chernovski, 1949) CE) antenna CHIRONOMINAE
39 TRIBE CHIRONOMINI
Parachiaronomue
Parachironomus five-segmented antennae
teeth of mentum pointed and fairly uniform in height.
Median tooth is usually slightly larger than remaining
teeth. ventromental plates with deep indentations on the anterior
margin (Fig. 26A)
first antennal segment longer than remaining four segments
(Fig. 26E)
Figure 26. Parachironomus. CA and C)mentum and ventromental plates CB) mand- ible CD) antenna TANYPODINAE 40 Ablabesmyia
Ablabesmyia
- darkly pigmented ligula with five teeth; anterior margin is concave or straight (Fig. 27 B,C,D)
- maxillary palp with more than one segment (Fig. 27A) - retractile, flve-segmented antenna
- one or more claws on posterior prolegs are pigmented (Fig.
27 E, F) - bifid paraglossa
- mandible with distinct lateral teeth (Fig. 27A)
c ~
Figure 27. Ablabesmyia. CA) mandible and maxillary palp CB, C, and D) glossa and paraglossa CE and F) pigmented spines on posterior prolegs TANYPODINAE 41 Coelotanypus Clinotanypus
Coelotanypus
- Iight-coloured llgula wlth seven teeth (Fig. 28A). Anterlor margln concave
- maxlllary palps wlth one segment
- mandlbles polnted, untoothed
- claws on posterior prolegs may be plgmented - paraglossa is bifid
Cllnotanypus
- light-coloured ligula with six teeth (Fig. 28C). Anterior margin concave
- maxi l1ary palps with one segment
- mandlbles polnted, strongly curved wlth one lateral tooth (Fig. 28B)
c
A B
Figure 28. (A) ligula of Coelotanypus (B) rnandible and rnaxillary palp of Clino tanyPlis (C) ligula of Clinotanypus. TANYPODINAE
42 Thienemannemyia group
Thienemannemyia group -maxillary palps with one basal segment -1 igu1a with five teeth, usually 1ight in colour: (Fig. 29A,B) -bifid paraglossa (~igure 29A,B)
-first lateral tee~h of 1[gula directed sI ightly outwards -apical tooth of mandible pointedj smal 1, almost indistinct lateral teeth (Figure 29 C,D) ·-lacks dorsomental teeth
B
~c
Figure 29. Thienemannemyia group. (A and H) ligula (C and D) mandibles-lateral teeth apparently absent. Note one-segmented maxillary palp. TANYPODINAE 43 P1'oaZadiuB
Procladius
-ligula with five dark, pointed teeth; anterior margin concave
(Figure 30A)
-w l th dorsomental teeth anterior to the, 1igula. No more than ten
teeth on each side (Figure 300)
-with a fringed or multi-spined paraglossa (Figure 30A)
Similar genera: Psectrotanypus has dorsomental teeth, five-
toothed (1 lqh t r co loured} llgulabut has a bifid
paraglossa.
8 -- Figure 30. Procladius. (A) ligula and paragloBsa (B) spines on posterior pro legs
Figure 30C. Procladius head capsule characters
Figure 30D. Procladius-dorsomental teeth TANYPODINAE
Tanypus 44
Tanypus - ligula with 5 light-coloured teeth; anterior margin
straight or slightly convex (Fig. 31A)
- dorsomental teeth present (Fig. 316)
- paraglossa has more than two spines - mandible may have a bulbous base and minute lateral tee th
(Fig. 31C) - maxJllary palp has one basal segment
Figure 31. Tanypus. (A) ligula (B) dorsomental teeth (C) mandible (D) antenna TANYPODINAE 45 Pseatrotanypus
Psectrotanypus
Type -ligula has four llght-colou{red teeth; anterlor margln 15
stralght - dorsomentum present anterior to the 1i guI a
- paraglossa ~as more than two spines - mandlble 15 polnted and has more than four distinct lateral
teeth (Figure 328)
Type 2
-ligula has five 1ight-coloured teeth; anterior margin is
strongly concave (Figure 32 A)
-dorsomental teeth present anterior to the 1igula. No more than ten teeth on each side -each paraglossa is bifid -mandibles are pointed, with three or fewer lateral teeth
SimiJar genera: Procladius has a dark, five-toothed ligula and a multi- spined paraglossa
~c A
~D )
Figure 32. PsectrotanyPus. (A and D) ligula and dorsomental teeth of type 2 (B,e, and E) mandible, dorsomental teeth and ligula of type l 46
REFERENCES
* Chernovskii, A.A. 1961. Identification of the 1arvae of the midge f ami1y , Tendipedidae. National Lending Libr~ry for Science and Techno1ogy, Boston Spa., Yorkshire.
** Hamilton, A.L., O.A. Saether and D.R. Oliver, 1969. A classification of the nearctic Chironomidae. Fisheries Research Board of Canada Technica1 Report No. 124, FRB Winnipeg, Manitoba.
* Johannsen, O.A. 1937a. Aquatic diptera. Part 3. Chironomidae: Subfami1ies Tanypodinae, Diamesinae, and Orthoc1adinae. Cornell Univ. Agric. Exper. Station: Memoir 205, 102 p.
* 1937b. Aquatic diptera. Part 4. Chironomidae: Subfami1y Chironominae. Corne11 Univ. Agric. Exper. Station: Memoir 210, 98 p.
** Lenz, F. 1936-1962. Tendipedidae (Chironomidae). Die Metamorphose. In: Lindner, E., Die F1iegen d. pa1aearctischen Region. l (13b-13). E. Schweizerbart' sche Vè'rLagsbuchhard'l.ung , Stuttgart.
* Mason, W.T. Jr., 1968. An introduction to the identification of Chironomid Larvae. Publication. of Federal Water Pollution Control Administration, U.S. Dept. of the Interior, Cincinnati. 89 p.
* Roback, S.S. 1957. The immature Tendipedids of the Philadelphia Area (Diptera: Tendipedidae). Acad. Nat. Sci. Phi1a. Monog. 9: 1-152.
** Saether, D.A., 1971a. Nomenclature and phy10geny of the genus Harnischia (Diptera; Chironomidae) Cano Ent. 103: 347-362.
** 1971b. Notes on genera1 morpho1ogy and t.e rmi.noLogy of the Chironomidae (Diptera). Cano Ent. 103: 1237-1260.
* Denotes i11ustrated ** Denotes a recommended reference