A Guide to the Zooplankton of Lake Champlain

Item Type Article

Authors Carling, Karen; Ater, Ian; Bouchard, Adam; Mihuc, Timothy

Publisher Scientia Discipulorum: SUNY Plattsburgh

Download date 29/09/2021 14:20:08

Link to Item http://hdl.handle.net/20.500.12648/1251 Plattsburgh State University of New York Volume 1 (2004) A Guide to the Zooplankton of Lake Champlain

Karen J. Carling, Ian M. Ater, Megan R. Pellam, Adam M. Bouchard, Timothy B. Mihuc (Faculty)

Lake Champlain Research Institute, Plattsburgh State University, Plattsburgh, NY

ABSTRACT

This key was developed by undergraduate research students working on a project with NYDEC and the Lake Champlain Monitoring program to develop long-term data sets for Lake Champlain plankton. Funding for development of this key was provided by, the Lake Champlain Basin Program through the U.S. Environmental Protection Agency (EPA) and the New York Department of Environmental Conservation (NYDEC). The key contains couplet keys for the major taxa in and Copepoda and a picture key to the major Rotifer plankton in Lake Champlain. All drawings are original by Ian M. Ater. Many thanks to the employees of the Lake Champlain Research Institute and the NYDEC for hours of excellent work in the field and in the lab: Robert Bonham, Adam Bouchard, Trevor Carpenter, Virginia Damuth, Jeff Jones, Marti Kroll, Dustin Lewis, Shannon Margrey, Tracy McGregor, Stephanie Stone and David Welch. We greatly appreciate the time and effort of Paula Woodward and Francis Dumenci in helping to put this guide together.

Keywords: Lake Champlain; zooplankton; identification; key

INTRODUCTION

Lake Champlain is one of the largest freshwater bodies in the United States. The Lake Champlain drainage basin is bordered by the Adirondack Mountains of New York to the west and the Green Mountains of Vermont to the east. This unique ecosystem has a surface area of 1130 km2, a length of 200 km and a mean depth of 19.4 m. The lake shoreline extends from Quebec in the north, 200 km south to Whitehall, New York, where it connects to the Hudson-Champlain canal. Islands and man-made transport causeways divide the lake into several distinct parts: Main Lake, South Lake, and Northeast Arm including Missisquoi Bay, and Malletts Bay. Malletts Bay and Missisquoi Bay are nearly isolated from the Northeast Arm, Malletts Bay by a narrow, shallow channel located between North and South Hero Islands, and Missisquoi Bay by an elongated shallow region (Meyer and Gruendling, 1979). The Northeast Arm is separated from the Main Lake by large islands that result in relative isolation (Shanley and Denner, 1999). South Lake is south of Crown Point it’s described as a river-like section that represents 40% of the lakes length, but less than 1% of its volume; while the Main Lake, which occupies the area from Rouses Point to Crown Point, represents 82% of the total volume (Meyer and Gruendling, 1979; Shanley and Denner, 1999). The Lake Champlain Monitoring Program has measured water quality variables and collected biological samples for plankton at 12-14 sites throughout Lake Champlain since the early 1990’s. Zooplankton sampling procedures were based on handbooks published by Vollenweider (1969) and Edmonson (1971). All sampling, (water quality and biological) was conducted by the New York Department of Environmental Conservation (NYDEC) and the New York State Museum staff. Zooplankton samples were taken as vertical net tows; from just above the sediment to the surface, using a 30cm diameter,

38 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

153micron mesh net. Net retrieval rate was 1 meter per second. All samples were preserved using a formalin-rose Bengal solution (Carling et al., in press). Lab identification was made to the lowest possible taxon using standard taxonomic keys (Balcer et al., 1984, Grothe and Grothe, 1977, Pennak, 1989, Thorp and Covich, 1991, Smith and Fernando, 1978) with verification as needed by regional experts (Carling et al. in press). While keys to the zooplankton of the Great Lakes exist, no key has been developed specific to Lake Champlain zooplankton. All identifications were made using a compound microscope with 200-800x oculars. Rotifers were allowed to settle in Sedgwick-rafter cells prior to identification. The following is a dichotomous key developed by student researchers at the Lake Champlain Research Institute. It is representative of the zooplankton identified in the samples collected by NYDEC between 1992-2001, and historical records from (Shambaugh et al., 1999, Myer and Gruendling, 1979, and Muenscher, 1929).

39 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

Helmet

ANTERIOR

Head length

Compound eye

Rostrum

First Antenna

Second Antenna DORSAL

Dorsal ramus Carapace

Ventral ramus Body length

VENTRAL Brood chamber

Postabdominal claw

Swimming Setae Shell spine Spine length

POSTERIOR

Figure 1 General morphology of Cladocera

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ANTERIOR Ey e

Second Antenna

Metasome First Antenna

Cep halic Segment

DORSAL VENTRAL

Urosome Genital Segment

Thoracic Legs

Caudal Rami

Lateral setae

Caudal setae (Terminal setae)

POSTERIOR

Figure 2 General morphology of Copepoda 41 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

Figure 3 Juvenile Daphnia

Figure 4 Nauplius 42 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

CLASSIFICATION OF LAKE CHAMPLAIN ZOOPLANKTON

PHYLUM ARTHROPODA Class Crustacea Subclass Order Cladocera Suborder Halopoda Family Leptodoridae—Leptodora Suborder Eucladocera SUPERFAMILY SIDOIDEA Family Sididae—Sida, Diaphanosoma Family Holopedidae— SUPERFAMILY CHYDOROIDEA Family Daphnidae—Ceriodaphnia, Daphnia Family Bosminidae—Bosmina, Eubosmina Family Chydoridae—Chydorus, Alona, Alonella, Pleuroxus Camptocercus, Acroperus, Eurycercus Subclass Copepoda Order Eucopepoda Suborder Family Pseudocalanidae—Senecella Family Centropagidae—Limnocalanus Family Temoridae—Epischura Family Diaptomindae—Leptodiaptomus, Skistodiaptomus Suborder Family —Acanthocyclops, Cyclops, Diacyclops, Eucyclops, Macrocyclops, Mesocyclops, Tropocyclops Suborder Harpacticoida

PHYLUM ROTIFERA Class Monogononta Order Flosculariacea Family Conochilidae—Conochilus Family Filiniidae—Filinia Order Ploimida Family Asplanchniadae—Asplanchna Family Brachionidae—Brachnoid, Keratella, Kelicottia, Nothalca, Branchionus Family Synchaetidae—Ploesoma, Polyarthra, Synchaeta Family Lecanidae—Monostyla, Lecane Family Trichocercidae—Trichocerca Family Gastropodiade—Ascomorpha, Gastropus Family Euchlanidae—Euchlanis Order Collothecacea Family Collothecidae—Collotheca Family Atrochidae—Cupelopagis

43 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004) SPECIES DISTRIBUTION LIST

South Lake Main Lake Northeast Arm North Lake Missisquoi Bay (site 4) (site 19) (site 34) (site 36) (site 50) Cyclopoid Cyclops scutifer X X X X Diacyclops thomasi X X X X X Eucyclops serrulatus X X X X Thermocyclops crassus X X X X X Mesocyclops/Macrocyclops X X X X X Tropocyclops X X X X X Acanthocyclops X X X X X Calanoid Copepods Epischura X X X X X Leptodiaptomus/Skistodiaptomus X X X X X Senecella calanoides X X X X X Limnocalanus X X X X X Harpacticoid Copepods Harpacticoid spp. X X X Cladocerans Bosmina longirostris X X X X X Bosmina spp. X X X X X Eubosmina X X X X X Ceriodaphnia X X X X X Daphnia longiremis X X X Daphnia mendotae X X X X X Daphnia retrocurva X X X X X Daphnia spp. X X X X X Alona bicolor X Chydorinae spp. X X X Diaphanosoma birgei X X X X X Diaphanosoma spp. X X X Holopedium gibberum X X X X X Leptodora kindti X X X X X Rotifera Asplanchna X X X X X Kelicottia X X X X X Keratella cochlearis X X X X X Keratella quadrata group X X X X X Nothalca squamala X X X X X Conochilus X X X X X Polyarthra X X X X X Brachinoid spp. X X X X X Branchionus calyciflorus X Ploesoma X X X X X Monostyla X X X X Synchaeta X X X X X Trichocerca X X X X X Filinia X X X X Ascomorpha/Gastropus X X X X X Lecane X Cupelopagis X Collotheca X Euchlanis X

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DEC monitoring sites

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Cladocera

1a. Thorax, abdomen, and thoracic appendages covered by a shell-like carapace….....…3

1b. Thorax, abdomen, and thoracic appendages not covered by carapace.……………....2

2. Body long and slender (up to 18mm long); eye is small, second antennae with approximately 50 swimming seta (Fig. 5)…………………………....Leptodora kindti

3a. Humpbacked , often a gelatinous sheath covers the back, swimming appendages unbranched in females (Fig. 6)………………..…..Holopedium gibberum

3b. Back not humped, no gelatinous sheath, swimming appendages branched in 2……..4

4a. Swimming appendages with more than 10 setae in a row on one side of the 2nd antennae…..………...…………………………...……………….…Family SIDIDAE, 5

4b. Swimming appendages with 10 or fewer setae on the 2nd antenna ……….... 6

5a. Rostrum (beak) present, >14 setae on the dorsal branch of the 2nd antennae (Fig. 7)… ……………………………………………………………….… Diaphanosoma birgei

5b. Rostrum (beak) not present, <14 setae on the dorsal ramus of the 2nd antennae, large compound eye present in the center of the head near the ventral margin (Fig. 8)..…… ……………………………………………………………………….. Sida crystallina body shapes can vary from ovate to ellipsoidal

46 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

Figure 5

(Leptodora kindti)

Figure 6 (Holopedium gibberum)

47 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

Figure 7 (Diaphanosoma birgei)

Figure 8 (Sida crystalline, lateral view)

48 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

6a. 1st antennae is a paired, tusk-like structure that is at least as long as head……...... ….7

6b. 1st antennae is covered by a beak-like structure, 2nd antennae is not covered; 3 segments on both branches…….…………………………..…Family CHYDORIDAE, 8

6c. 1st antennae is not a paired, tusk-like structure………………………………...…....9

7a. Posterior shell spine present (Fig. 9).……..………………….…Bosmina longirostris

7b. No posterior shell spine present (Fig. 10)….………………….…Eubosmina coregoni

8. Resemble Family BOSMINIDAE but often have a postabdominal claw that extends beyond carapace, claw is much larger than that of Family BOSMINIDAE. Often have fine hairs or pecten along the ventral side of carapace (see genera Fig. 11-17) ……… …………...…...………………………………………………..Family CHYDOROIDEA

9a. Rostrum (beak) present, posterior shell spine located at midline of carapace; helmet shapes vary………...... …...…………………………………Family DAPHNIDAE, 10

9b. Rostrum (beak) absent, head is small and compacted; ventral side is rounded (Fig. 18).……………………. …………………...…Family DAPHNIDAE, Ceriodaphnia antennae fixed and branched; 3 segments on each branch, single compound eye present

10a. Setae at the base of the second segment of the dorsal ramus of the antennae is longer than the ventral ramus………………………………………...…………….11

10b. Setae at the base of the second segment of the dorsal ramus of the antennae is shorter than the ventral ramus (Fig. 19)...…………..…………...Daphnia longiremis Peak of helmet generally rounded in adults, varying shapes in juvenile.

11a. Setae from the dorsal ramus at least ½ the length of the longest seta on the base of the ventral ramus (Fig. 20).………………………………………Daphnia mendotae Peak of helmet near midline of body in lateral view; ocellus present (difficult to see)

11b. Seta from the dorsal ramus extends below the ventral ramus but not as far as ½ the length of the longest seta at the base of the ventral ramus (Fig. 21)……….………… …………………………………………………………………...Daphnia retrocurva Peak of helmet of adults generally parallel to or extended past the dorsal of carapace, when in lateral view, no ocellus present

49 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

Shell spine

Sensory Bristles

Figure 9. (Bosmina longirostris)

Figure 10. (Eubosmina coregoni)

50 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

Figure 11. Chydorus sp. Figure 12. Alonella sp.

Figure 14. Eurycercus sp.

Figure 13. Alona sp.

Figure 16. Pleuroxus sp.

Figure 15. Camptocercus sp.

Figure 17. Acroperus sp.

51 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

Figure 18

(Ceriodaphnia)

Figure 19 (Daphnia longiremis)

Figure 20 Figure 21 (Daphnia mendotae) (Daphnia retrocurva)

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Copepoda

1a. Metasome and urosome NOT distinctly separate; first antennae shorter than cephalic segment (Fig. 22).…………………………………..…….. Suborder HARPACTICOIDA Not often found in plankton samples because they are mainly benthic and littoral organisms. 1b. Urosome noticeably narrower than metosome; first antennae generally as long or longer than cephalic segment……………..……………………………………….….2

2a. First antennae reaching to or beyond caudal rami……….…..Suborder CALANOIDA, 3

2b. First antennae not reaching past genital segment….…..…..Suborder CYCLOPOIDA, 10

Calanoida

3a. Caudal ramus with 3 broad terminal setae in addition to shorter inner and outer setae or spines (Fig. 23).………..…………………………………….…Epischura lacustris Adult females have twisted urosomes with short thick spines on outer corner of the caudal rami. Adult males have smaller spines on the rami and enlarged lateral processes on the right side of urosome.

3b. Caudal ramus with 4 well-developed terminal setae in addition to slender inner and outer setae; body length 2.4 -2.7mm (Fig. 24)….……………....Senecella calanoides

3c. Caudal ramus with 5 well-developed terminal setae………….………………………4

4a. Caudal ramus more than three times as long as wide; large animals up to 3.0mm (Fig. 25)…..………………………………………..……..……….Limnocalanus macrurus

4b. Caudal ramus length less than or equal to three times width; terminal setae of caudal ramus approximately equal in length……………………….Family , 5

5a. Last metosomal segment extended into pointed wings…………………………….....6

5b. Last metosomal segment not extended into pointed wings…………………………..7

6a. 3 urosomal segments, metosomal wings pointed, triangular (Fig. 26)..………………. …………………………………………………………, female

6b. Greater then 3 urosomal segments………..………………………………….……..9

7a. Last metosomal segment rounded with small spines at the corners………………….8

7b. Last metosomal segment rounded without small spines at corners (Fig. 27)………… ……………………………………...…………Skistodiaptumus oregonenesis, female Three urosomal segments

53 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

8a. Two or four urosomal segments (Fig. 28-29).………….…… Two segments, female/Four segments, male

8b. Three urosomal segments …………..….………...Skistodiaptomus pygmaeus, female

9a. Four urosomal segments (Fig. 30).…………...…Skistodiaptomus oregonenesis, male

9b. Five urosomal segments (Fig. 31)….…………...……….Leptodiaptomus sicilis, male

Figure 22 Figure 23 Figure 24 (Harpacticoida) (Epischura lacustris) (Senecella calanoides)

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Metasomal Wings

Figure 25 (Limnocalanus macrurus) Figure 27 Figure 26 (Skistodiaptumus (Leptodiaptomus sicilis) oregonenesis)

Ig Figure 28 Figure 29 Figure 30 Figure 31 to(Leptodiaptomus minutus) (Leptodiaptomus minutus) (Skistodiaptomus oregonenesis) (Leptodiaptomus sicilis) female male male male 55 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

Cyclopoida 10a. Inner caudal seta long, at least twice the length of ramus...…………..…...………11 10b. Inner caudal seta short, less than twice length of ramus………..…..…...………...14

11a. Inner caudal seta less than ½ length of longest caudal seta (Fig. 32)………………... ………………………………………………………………...Macrocyclops albidus ………………………………………………………….(Fig. 33) Macrocyclops ater

11b. Inner caudal seta longer than ½ length of longest caudal seta……………….…….12

12a. 5 caudal seta (inner margins of caudal ramus usually hairy) (Fig. 34)………………. ……………………………………………………………………..Mesocyclops edax 12b. Less than 5 caudal seta…………………………………………………………….13

13a. First antennae with 17 segments (Fig. 35)..………………...Thermocyclops crassus*

13b. First antennae half the length of cephalic segment with setae that extend to the end of metosome. 2 caudal seta both long, one nearly as thick as caudal ramus (Fig. 36) …………………………………………………………………….…..Ergasilus spp.* Noticeable claws between antennae, used to attach to fish gills. Claws very large in females.

14. First antennae at least ¾ length of cephalic segment……………..…………...…...15

15a. Small animals (0.5-0.8mm); extended first antennae reach genital segment (Fig. 37) ..….……………………………………………………………….Tropocyclops spp. 15b. Animals larger than 0.7mm; first antennae do not reach genital segment……..…..16

16a. Outer caudal seta modified into a spine thicker than inner caudal seta (Fig.38)……. ………………………………………………………………………Eucyclops spp.* High magnification shows a row of fine spinules on outer margin of caudal rami of females * Species rare in Lake Champlain

16b. Outer caudal seta not thicker than inner seta…….………………………..……….17

17a. Inner margin of caudal rami with fine hairs (using high magnification), caudal rami 4 times as long as broad (Fig. 39)….…………….…………...……Cyclops scutifer* Fourth and fifth metasomal segments expandinto pointed wings.

17b. Inner margin of caudal rami without hairs (using high magnification), caudal rami elongated, 5-7 times as long as wide…..………………………………………..…18

18a. Lateral seta located on the posterior ¼ of caudal ramus (Fig. 40)…………………… ……………………………………………………………...Acanthocyclops robustus

18b. Lateral seta located near the middle of ramus (Fig.41)..…....…...Diacyclops thomasi

56 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

Figure 32 Figure 33 Figure 34 (Macrocyclops albidus) (Macrocyclops ater) (Mesocyclops edax)

Figure 35 Figure 36 (Thermocyclops crassus) (Ergasilus spp.)

57 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004)

re Figure 37 Figure 38 Figure 39 (Tropocyclops spp.) (Eucyclops spp.) (Cyclops scutifer)

Figure 40 Figure 41 (Acanthocyclops robustus) (Diacyclops thomasi)

58 A guide to the Zooplankton of Lake Champlain Plattsburgh State University of New York Volume 1 (2004) KEY FEATURES IN LAKE CHAMPLAIN ROTIFERS

Asplanchna Round to oval shape and highly transparent. Size is from 500-1500μ Corona is a single ring of cilia. Foot is absent. Trophi incudate. Dorsal antennae double and lateral antennae large and distinct. One cerebral eye present.

Kelicottia Conical shape terminating into a very long caudal spine. Size is from 400-800μ. Corona has 3 ciliated lobes. Foot is absent. Trophi malleate. Dorsal antennae on a tentacle extended between the anterior spines. Lateral antenna very small located on the middle of body. One red eye present. Spines located asymmetrically, anterior dorsal margin with 4-6 spikes of varying length.

Keratella quadrata Rectangular shape. Size is from 100-300μ. Corona is 3-lobed with ventral dip. Foot is absent. Trophi malleate. Dorsal antenna on a tentaculate process between the median spines, lateral antenna behind the middle of the body. One cerebral eye present. Dorsal plate slightly domed covered with a patter of polygons. Anterior dorsal margin with 6 spines and posterior margin has 2 spines.

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Keratella cochlearis Oblong-rectangular shape. Dorsal plate domed. Size is from 150-250μ. Corona is 3-lobed with ventricle dip. Foot is absent. Trophi malleate. Dorsal antenna on a tentaculate process between the median spines, lateral antenna behind the middle of the body. One cerebral eye present. Dorsal plate slightly domed covered with a patter of polygons. Anterior dorsal margin with 6 spines and posterior margin has 1 spines.

Polyarthra Transparent rectangular or square shape. Size is from 80-220μ. Corona is a circumapical band of cilia. Foot is absent. Trophi virgate. Small lateral antenna behind the middle of the body at the posterior corners. Large red cerebral eye present. Anterior third of the body has 2-4 bundles each consisting of 3 fin-like foliated appendages.

Conochilus Round-vase shape tapering off to a long unsegmented retractile foot. Size is from 300-1200μ (depends on the length of the foot). Corona is a horseshoe shape with a double band of cilia. Foot is unsegmented and retractile. Toes absent. Trophi malleoramate. Two eyes present behind corona. Often found in colonies.

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Nothalca sqamala Transparent oblong-oval, elongate in shape. Size is from 100-200μ. Corona has 3 lobes and two additional ventro-lateral lobes. Foot is absent. Trophi malleate. Dorsal antennae on a small bulge. One reddish eyespot present. Anterior dorsal plate with 6 short spines of varying length.

Filinia Oval shape. Size is from 70-250μ. Corona is a single ring of cilia. Foot is absent. Trophi malleoramate. Dorsal antenna on the neck, lateral antenna behind middle of the body. Two eyes fairly close on apical field. Below the head there are two bristles and above the head there is one bristle, all of varying lengths.

Ascomorpha Transparent oval oblong shape. Size is from 50-200μ. Corona is a single ring of cilia. Foot is absent. Trophi virgate. Antenna is not very visible but is located in the middle of the body not clearly visible. Eye cerebral present.

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Euchlanis Oval transparent shape. Size is from 200-600μ. Corona consists of an incomplete ring of cilia. Foot is made up of two segments, toes are located on the second segment and are tapered. Trophi malleate. Antenna small and located on dorsal plate. One cerebral eye is present. Posterior end is divided in the middle to form a v-shape notch.

Gastropus Irregular oval shape and laterally compressed. Size is from 100-350μ. Corona is a band of cilia. Foot is annulated and located near the posterior. Toes short and tapered to a point. Trophi virgate. Dorsal antenna visible. One large cerebral eye.

Collotheca Spindle transparent shape body tapering into a long retractile foot. Size is from 100-500μ. Corona consists of a ring of mobile cilia. Lobes may be present on the corona and have long bristles. Foot is long and unsegmented. Trophi uncinate. Dorsal antenna minute.

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-

Brachinoid Oval to rectangular shape. Size is from150 -500μ. Corona is 5 distinct lobes with sensory bristles between them. Foot is located at posterior end. Foot is often retracted and may be bordered by 2 short spines. Trophi malleate. Dorsal antenna between the frontal spines, lateral antenna behind the middle of the body. One cerebral eye. Anterior dorsal margin with 2 to 6 spines. Posterior may also have spines.

Branchionus calyciflorus Oval shape. Size is from 180-570μ. Corona is 5 distinct lobes with sensory bristles between them. Foot is present located at posterior end. Foot is retracted and bordered by two short spines. Trophi malleate. Dorsal antenna between the frontal spines, lateral antenna behind the middle of the body. One cerebral eye. Anterior margin has 4 dorsal spines of varying length and shape, the outer two are longer then the inner two.

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lateral view dorsal view Pleosoma Oblong bean shape. Size is from150-600μ. Corona is a single ring of cilia. Foot is located medially on ventral plate, large and strong. Toes short and taper into a point. Trophi virgate. Dorsal antenna small anterior to or in the middle of the body, lateral antenna insignificant. Eye Present.

Monostyla Oval or oblong. Size is from 100-150μ. Corona is a circuapical band. Foot is composed of two segments one longer then the other; first segment may or may not be readily observable. Trophi malleate. Anterior dorsal with a deep V-shape sinus. Single large cerebral eye. Anterior dorsal margin with shallow or deep v-shaped sinus. (Note: the monostyla is very similar to the Lecane)

Lecane Circular or oblong shape. Size is 200-300μ. Corona is a circuapical band. Foot is short with two segments, second segment has two toes which may be fused together. Trophi malleate. Single large cerebral eye. Anterior dorsal has a V-shaped sinus.

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Synchaeta Conical or vase form shape. Size is 200-600μ. Corona is broad and oval with broken bands of cilia and with wide-branching auricles. Foot is unsegment. Toes are short and often taper into a point. Trophi virgate. Dorsal antenna in the neck region. Eye often present, single or double.

Trichocerca Elongated cylinder shape. Size is from 200-600μ. Corona is on the apical field one or more palps (elongated, often segmented appendages). Foot is short with a pointed toe may be as long as the body. Trophi malleate. Dorsal antenna between the ridges, lateral antennae often very asymmetrical. One cerebral eye.

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BIBLIOGRAPHY Bacler, M., Korda, N., Dodson, S. A. 1984. Zooplankton of the Great Lakes: A Guide to the Identification and Ecology of the Common Species. University of Wisconsin Press. 74-101 p.

Carling, K. J., Mihuc, T. B., Siegfried, C., Bonham, R., Dunlap, F. In Press. Where Have All the Rotifers Gone? Zooplankton Community Patterns in Lake Champlain From 1992-2001. In: Lake Champlain in Transition: From research Toward Restoration (Manley, Manley, Mihuc, eds.). Kluwer Academic Press.

Chengalath, R., Fernando, C.H., George, M.G. 1972. The Planktonic Rotifera of Ontario with Keys to Genera and Species. Unviersity of Waterloo. Waterloo, Ontario, Canada.

Edmondson, W. T., (ed.). 1971. A Manual on Methods for the Assessment of Secondary Productivity in Fresh Waters. Blackwell Sci. Publ., Oxford. 358 p.

Grothe, D.W. and Grothe, D. R. 1977. An Illustrated Key to the Plankton Rotifers of the Laurentian Great Lakes.*

Jersabek, C. D., Segers, H., Morris, P. J. An Illustrated online catalog of the Rotifera in the Academy of Natural Sciences of Philadelphia (version 1.0: 2003-April-8). 2003-04-15 15:23 EDT .

Muenscher, W.G. 1929. Plankton studies in the Lake Champlain watershed. In: A biological survey of the Lake Champlain watershed. NY State Conservation Dept., Supplement to the 19th Annual Report.

Myer, G.E. and Gruendling, G. K. 1979. Limnology of Lake Champlain, Lake Champlain Basin Study. New England River Basins Commission Burlington VT.

Pennak, R.W. 1989. Fresh-water invertebrates of the United States: Protozoa to Mollusca 3rd ed. Wiley-Interscience, New York.

Shambaugh, A., Duchovnay, A., McIntosh, A. 1999. A Survey of Lake Champlain’s Plankton In: Lake Champlain in Transition: From Research Toward Restoration, Water Science Application 1. American Geophysical Union, Washington.

Smith, K. and Fernando, C. H. 1978. A guide to the Freshwater Calanoid and Cyclopoid Copepod Crustacea of Ontario. Unviersity of Waterloo. Waterloo, Ontario, Canada.

Thorp, J., and Covich, A., (ed.). 1991. Ecology and Classification of North American Freshwater Invertebrates. Academic Press. San Diego, California.

Vollenweider, R.A., (ed.). 1969. A Manual on Methods for Measuring Primary Production in Aquatic Environments. Blackwell Sci. Publ., Oxford. 211 p.

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