Revised EPT List, and yes, those nymphs were Acroneuria evoluta

Still sweating it out -- literally! -- in central Virginia, and it's supposed to be hotter next week.

Steven Beaty has confirmed that, using current species descriptions, the nymph in the photo at the top of the page appears to be Acroneuria evoluta.  (See the entry of 6/12.)  So, it is a species we find in the Rivanna, usually in the fall, and I've found it at Darden Towe Park in C'ville, and in Fluvanna County at the Crofton bridge.  Apparently, this is the first time this species has been recorded in the state of Virginia.

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On 9/8/12, I posted an EPT List for central Virginia.  While I've tried to update that as things have proceeded, I think it's worthwhile to post a "revised" list based that shows where things stand at the moment.  Here it is.

              EPT Species List for Central Virginia

              (Albemarle, Greene, Madison, Fluvanna)

                 

I. Ephemeroptera (Mayflies)

1. Ameletidae

1. Ameletus lineatus

2. Ameletus cryptostimulus

2. Baetidae (Small minnow mayflies)

1. Acentrella nadineae

2. Acentrella turbida

3. Baetis flavistriga

4. Baetis intercalaris

5. Baetis pluto

6. Baetis tricaudatus

7. Heterocloeon curiosum

8. Heterocloeon amplum

9. Heterocloeon petersi

10. Iswaeon anoka

11. Labiobaetis propinquus

12. Plauditus dubius

3. Isonychiidae (Brushlegged mayflies)

1. Isonychia sp.

4. Heptageniidae (Flatheaded mayflies)

1. Cinygmula subaequalis

2. Epeorus pleuralis

3. Epeorus vitreus

4. Epeorus fragilis

5. Heptagenia marginalis

6. Leucrocuta hebe

7. Leucrocuta juno

8. Leucrocuta aphrodite

9. Leucrocuta thetis

10. Maccaffertium ithaca

11. Maccaffertium meririvulanum

12. Maccaffertium pudicum

13. Maccaffertium vicarium

14. Maccaffertium modestum

15. Rhithrogena sp. (exilis?)

16. Rhithrogena sp.

17. Stenacron carolina

18. Stenacron interpunctatum

5.  Ephemerellidae (Spiny crawler mayflies)

1. Drunella cornutella

2. Drunella tuberculata

3. Drunella walkeri

4. Ephemerella dorothea

5. Ephemerella invaria

6. Ephemerella subvaria

7. Eurylophella verisimilis

8. Eurylophella funeralis

9. Eurylophella sp. (minimella?)

9. Serratella serratoides

10. Serratella serrata

11. Teloganopsis deficiens

6. Leptohyphidae (Little stout crawler mayflies)

1. Tricorythodes

 *7. Caenidae (Small square-gill mayflies)

1. Caenis sp.

*8. Baetiscidae (Armored mayflies)

1. Baetisca sp.

9. Leptophlebiidae (Pronggilled mayflies)

1. Paraleptophlebia mollis

2. Paraleptophlebia guttata

3. Habrophlebia vibrans

4. Leptophlebia

10. Ephemeridae (Common burrower mayflies)

1. Ephemera guttalata

 II. Plecoptera (Stoneflies)

1. Capniidae (Small winter stoneflies)

1. Allocapnia sp.

2. Paracapnia angulata

2. Leuctridae (Needleflies)

1. Leuctra sp.

3. Nemouridae (Forestflies)

1. Amphinemura sp.

2. Ostrocerca truncata

3. Prostoia completa

4. Soyedina sp.

4. Taeniopterygidae (Large winter stoneflies)

1. Strophopteryx fasciata

2. Taenionema atlanticum

3. Taeniopteryx burksi/maura

5.  Chloroperlidae (Green stoneflies)

1. Alloperla sp.

2. Haploperla brevis

3. Sweltsa sp.

6. Peltoperlidae (Roach-like stoneflies)

1. Peltoperla sp.

2. Tallaperla sp.

3. Viehoperla sp.

7. Perlidae (Common stoneflies)

1. Acroneuria abnormis

2. Acroneuria carolinensis

3. Acroneuria sp. (possibly internata, possibly a variety of abnormis)

4. Acroneuria evoluta

5. Acroneuria lycorias

5. Agnetina annulipes

6. Agnetina capitata

7. Agnetina flavescens

8. Eccoptura xanthenses

9. Neoperla sp.

10. Paragnetina immarginata

11. Paragnetina fumosa

12. Perlesta sp.

8. Perlodidae (Springflies and Stripetails)

1. Clioperla clio

2. Diploperla duplicata

3. Helopicus subvarians

4. Isogenoides hansoni

5. Isoperla dicala

6. Isoperla holochlora

7. Isoperla holochlora "A"

8. Isoperla latta

9. Isoperla montana (group)

10. Isoperla similis

11. Isoperla davisi

12. Isoperla orata

13. Isoperla orata (variant form)

14. Isoperla sp.VA

15. Malirekus hastatus

16. Rememus bilobatus

9. Pteronarcys (Giant stoneflies)

1. Pteronarcys biloba

2. Pteronarcys dorsata

3. Pteronarcys proteus

III. Trichoptera (Caddisflies)

1. Rhyacophilidae (Free-living caddisflies)

1. Rhyacophila carolina

2. Rhyacophlia fuscula

3. Rhyacophila nigrita

4. Rhyacophila glaberrima

5. Rhyacophila ledra/fenestra

6. Rhyacophila sp. (banksi?)

*2. Hydroptilidae (Micro caddisflies)

1. Hydroptila sp.

3. Glossosomatidae (Saddle-case makers)

1. Glossosoma nigrior

4. Philopotamidae (Fingernet caddisflies)

1. Chimarra sp.

2. Dolophilodes distincta

3. Wormaldia sp.

5. Polycentropodidae

1. Polycentropus sp.

6. Hydropsychidae (Common Netspinners)

1. Ceratopsyche alhedra

2. Ceratopsyche bronta

3. Ceratopsyche morosa

4. Ceratopsyche slossonae

5. Ceratopsyche sparna

6. Cheumatopsyche sp.

7. Diplectrona modesta

8. Diplectrona metaqui

9. Hydropsyche betteni

10. Hydropsyche rossi

11. Hydropsyche venularis

12. Macrostemum sp.

 *7. Phryganeidae (Giant case-makers)

1. Phryganea sp. (sayi?)

8. Brachycentridae (Humpless case-makers)

1. Adicrophleps hitchcocki

2. Brachycentrus appalachia

3. Micrasema wataga

4. Micrasema charonis

5. Micrasema bennetti

6. Micrasema sp. (scotti?)

9. Lepidostomatidae

1. Lepidostoma sp. (at least 2 different species, possibly more)

2. Theliopsyche sp.

10. Limnephilidae (Northern case-makers)

1. Ironoquia punctatissima

2. Pycnopsyche gentilis

3. Pycnopsyche scabripennis

4. Pseudostenophalyx sparsus

11. Apataniidae

1. Apatania incerta

12. Goeridae

1. Goera calcarata

2. Goera fuscula

 13. Uenoidae

1. Neophylax oligius

2. Neophylax consimillis

3. Neophylax aniqua

4. Neophylax mitchelli

5. Neophylax fuscus

6. Neophylax concinnus

14. Leptoceridae (Long-horned case-makers)

1. Nectopsyche equisita

2. Oecetis sp.

3. Ceraclea maculata

15. Odontoceridae (Strong case-makers)

1. Psilotreta labida

2. Psilotreta frontalis

3. Psilotreta rufa

16. Molannidae (Hooded-case maker)

1. Molanna blenda

As I've done in the past, I will make changes to this as needed.

New discoveries: the 2014-2015 season

(Perlodid stonefly, genus Kogotus: Clark Fork River in Montana, August 18. 2014.)

I think of the annual "season" as starting each fall and ending the following spring.  So, the 2014-2015 season is pretty much over.  True, I might find a new species or two in the Rivanna River this summer, but in most of the streams that I visit the annual cycle is finished.  So, what did we discover this year in terms of new species (EPT species)?

1. 10/28/14 and 12/27/14.  The common stonefly, Acroneuria lycorias, which we distinguished from Acroneuria carolinensis.

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2. 12/21/14.  A new genus of Lepidostomatid: Theoliopsyche.

This one was not in its own case: that case belongs to a Pycnopsyche gentilis caddisfly larva.  Still, it was a good find since this genus is not all that common.
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3. 12/27/14.  A new genus of crane fly: Dicranota.

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4. 1/2/15.  A humpless case-maker that one of my friends had found twice before, but this was the first time I had seen it: Adicrophleps hitchcocki.

This species is "imperiled" in the state of Virginia.
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5. 1/19/15.  A new Isoperla Perlodid: Isoperla latte.   Found -- where else? -- at the Rapidan River.

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6. 4/12/15.  And a new Nemourid stonefly: Ostrocerca truncata.

7. and 8.  To these we should add two caddisfly species that my friend discovered (for which, see the entries of 11/11/14 and 11/17/14):  Molanna blenda and Psilotreta rufa.
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Summer is here, and it's here in spades!  Day after day our temperatures have been in the 90's with dew points as high as 74º.  Sure hope this abates.   I can't do any stream work until it does.

Was it A. arenosa or A. evoluta? -- a common stonefly (Perlid) that I've only found in the Rivanna

When I found this stonefly on 11/14/13 in the Rivanna at Crofton, I regarded it as a form of Acroneuria abnormis.  When I found it again on 9/1/14,

I did a little more work, concluding, you will recall, that it was actually A. arenosa, or possibly A. evoluta (see the entries of 9/1 and 9/4).   I've worked on it some more, and the evidence points strongly in the direction of A. evoluta.  Let me review what I've recently found.  I'll begin with two points on the "positive"side.

1.  The pattern we see on the head is more in agreement with the description of A. evoluta than with that of A. arenosa.

A. arenosa: "dorsum of head with M-shaped pattern, sometimes faint to absent."  (Beaty, "The Plecoptera of North Carolina," p. 14)

A. evoluta: "dorsum of head with interrupted M-shaped head pattern, appearing as a transverse row of 3 light spots in front of anterior ocellus."  (Beaty, p. 14)

There is indeed "a transverse row of 3 light spots" on the head.

2. Beaty notes that this nymph "keys in Unzicker and McCaskill (1982) to A. mela."  For this information, see Unzicker and McCaskill, "Plecoptera," Chapter 5 in Brigham, Brigham, and Gnilka, ed., Aquatic Insects and Oligochaetes of North and South Carolina, 1982.   The description of A. mela is found on page 5.32.  More important for us -- figure 5.87 on page 5.35 is an illustration of this Acroneuria species, and that illustration is a dead ringer for the nymphs I have found.  (A. mela is now regarded as a synonym of A. evoluta.)
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And now for the evidence on the negative side.  Again there are two arguments that we can make.

1. In his description of A. arenosa, Peter Claassen (Peter W. Claassen, Plecoptera  Nymphs of America (North of Mexico), 1931.  pp. 84-85) says the following about the abdominal segments:  "Abdominal segments brownish, with a row of roundish, yellow spots along the median dorsal line, and with similar spots on the lateral margin of the posterior segments."

2. and in the photo of A. arenosa posted by Chandler (http://www.discoverlife.org/mp/20q?search=Acroneuria+arenosa) those yellow spots are clear.  There are no yellow spots on the median dorsal line of the nymphs I have found.

I'd say we're finding A. evoluta.  There is only one argument against this identification, and it's one I've noted before (9/4/14): A. evoluta is not attested in the state of Virginia according to NatureServe Explorer (http://explorer.natureserve.org/), nor is it verified as a Virginia Acroneuria by Stewart and Stark (Nymphs of North American Stonefly Genera, p. 316).   But since we know it is found in the rivers of Pennsylvania, Tennessee, North Carolina and Georgia (Stewart and Stark), I don't see why it shouldn't be here.

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Additional photos:

A review: Common stonefies (Perlidae), genus Acroneuria

I thought I'd make myself useful, while I wait for a crummy summer cold to let go.  This is something I've been wanting to do for myself as well as anyone else who enjoys reading along.

"Common stoneflies" (family Perlidae), genus Acroneuria: what are the species we see?  Two comments before we begin.  1) Genus Acroneuria Perlids are the most common, "common" stoneflies we see in our streams, and 2) keep in mind that this is a genus that Beaty insists is badly in need of additional work and revision.

1. Acroneuria abnormis

(That's also abnormis in the photo at the top of the page.)  This is the most common Acroneuria species I've seen, and I think I've seen it in every stream that I've explored, from the very smallest headwater streams to sizeable rivers like the Rivanna.  Distinguishing features: distinct M-shaped pattern on head, no anal gills, and banded tergites -- anterior dark, posterior light.  Tolerance value: 2.1.
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2. Acroneuria arenosa (could also be Acroneuria evoluta)

To date, this is a species I've only found in the Rivanna.  So, a "river" insect.  Distinguishing features: M-shaped pattern on head pale to absent (arenosa) or reduced to three dots (evoluta), terga uniformly brown, anal gills present.  Tolerance value: 2.4 (arenosa) or 1.7 (evoluta).
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3. Acroneuria carolinensis

Thrives in clean, cold streams of "medium" size -- in my experience at least (upper Doyles, Rapidan, North Fork of the Moormans).  Distinguishing features: head with light M-shaped pattern, banded terga: anterior light, posterior dark, no anal gills present.  Tolerance value: 1.2.
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4. Acroneuria internata (but nymph in photo might be a form of A. abnormis)

This is a species that I've only seen once: small mountain stream, Entry Run in Greene County.   The distinguishing feature is the banding of the abdominal terga: the light posterior bands are of uniform thickness.  (In this case, the light bands are nearly uniform.)  No tolerance value is listed for this species in the documents provided by North Carolina.
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5. Acroneuria lycorias

Similar to A. carolinensis in appearance.  But, A. lycorias has anal gills, and the banding is fairly uniform with no medial markings.  Fairly common in Buck Mt. Creek.  Tolerance value: 2.1.

Beaty provides descriptions for three other species: filicis, frisoni, and perplexa.  These are species that I haven't seen.  All three appear to be relatively uncommon.  (Steven Beaty, "The Plecoptera of North Carolina, p. 14)