1a.
|
Terrestrial species. First pair of antennae
inconspicuous, rudimentary and not 1/4 as long as the second pair;
abdominal segments distinct.
|
[2]
|
1b.
|
Aquatic species. First pair of antennae
plainly visible and at least 1/4 long as second pair; posterior segments
of abdomen fused.
|
[17]
|
|
G
Stoner Rife 1993, After AAW 1964 |
|
2a.
|
Uropods not extending beyond the terminal
abdominal segment; capable of rolling into a ball
|
[3]
|
|
G
Stoner Rife 1993, After AAW 1964 |
|
2b.
|
Uropods extending beyond the terminal
abdominal segment; not capable ofrolling into a ball (except Cylisticus
convexus)
|
[5]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
3a.
|
Median lobe of head extending dorsally and
interiorly as a flat, truncate horn, with a deep groove in back of the
horn.
|
Armadillidium
nasatum
|
3b.
|
No horn or groove extending from median lobe
of head.
|
[4]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
4a.
|
Telson hour glass shaped, not triangular in
form; all five pairs of pleopods bear pseudotracheae.
|
Venezillo
evergladensis
|
4b.
|
Telson triangular, not hour glass shaped;
First two pairs of pleopods bear pseudotracheae, very common in sunny
areas under boards and foundations.
|
Armadillidium
vulgare
|
|
G
Stoner Rife 1993, After AAW 196 |
|
5a.
|
Flagellum of second antennae with 2 or 3
articles, and adults larger than 6mm.
|
[6]
|
5b.
|
Flagellum of second antennae with 4 to many
articles, those with less than 5 articles, less than 6mm in length, those
with 10 or more articles may be up to 9mm in length.
|
[11]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
6a.
|
Flagellum of second antennae with 3
articles, prominent lobes on either side of head.
|
Oniscus
asellus
|
6b.
|
Flagellum of second antennae with 2
articles.
|
[7]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
7a.
|
Abdomen abruptly narrower than the thorax;
antennae usually conspicuously banded with white at the joints.
|
Porcellionides
pruinosus
|
7b.
|
Abdomen not abruptly narrower than the
thorax; banding of antennae absent or inconspicuous.
|
[8]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
8a.
|
Tergites 3, 4, and 5 distinctly narrower
than the other tergites, deep triangular notches between the lateral
expansions of tergites 2 and 3, 3 and 4, and 4 and 5; median lobe of head
acute; outline of body in cross section strongly arched, capable of
rolling into a ball.
|
Cylisticus
convexus
|
8b.
|
Tergites 3, 4, and 5 the same width as other
tergites, all notches between lateral expansions of tergites have parallel
sides; median lobe of head not acute; outline of body in cross section,
not strongly arched; not capable of rolling into a ball.
|
[9]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
9a.
|
All five pairs of pleopods with
pseudotracheae (not visible in 70% alcohol) and appear opaque white in
color, posterior margin of first segment of pereon strongly curved.
|
Trachelipus
rathkei
|
9b.
|
First two pairs of pleopods with
pseudotracheae (not visible in 70% alcohol) and only first two pairs
appear opaque white the rest appear translucent; posterior margin of first
segment of the pereon more or less straight.
|
[10]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
10a.
|
Antennal segments 2-4 strongly carinate,
dorsal carinae of segments 2 and 3 produced into strong spines; head and
body with conspicuous tubercles; median head lobe broad and truncate;
posterio-lateral corner of first tergite produced posteriorly head dark
gray; body yellowish gray with brown patches and a row of light spots on
either side of mid-dorsal line.
|
Porcellio
spinicornis
|
10b.
|
Antennal segments 2-4 not strongly carinate,
no spines; head and body with conspicuous tubercles; median head lobe
triangular posterio-lateral corner of first tergite produced posteriorly;
head and body dark gray.
|
Porcellio
scaber
|
10c.
|
Antennal segments 2-4 not strongly carinate,
no spines; head and body smooth without conspicuous tubercles median head
lobe triangular; posterio-lateral corner of first tergite not produced
posteriorly; head and body light gray with tiny light spots on the head
and with a cluster of light spots on each side of the tergites.
|
Porcellio
laevis
|
|
G
Stoner Rife 1993, After AAW 196 |
|
11a.
|
Flagellum of second antennae with 10 or more
distinct segments; inner branch of uropods longer than outer branch.
|
Ligidium
elrodii
|
11b.
|
Flagellum of second antenna with less than 5
articles; inner branch of uropods shorter than or equal to the outer
branch.
|
[12]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
12a.
|
Dorsal surface with pronounced longitudinal
ridges, less than 4mm in length, white, slow moving and easily mistaken
for juveniles of other species.
|
Haplophthalmus
danicus
|
12b.
|
Dorsal surface without pronounced
longitudinal ridges; dorsal surface smooth or with bumps or spines.
|
[13]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
13a. .
|
Dorsal surface appears smooth
|
[14]
|
13b.
|
Dorsal surface appears rough.
|
[15]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
14a.
|
Three ocelli; color pinkish.
|
Trichoniscus
pusillus
|
14b.
|
One ocelli; deep purple color.
|
Hyloniscus
riparius
|
|
G
Stoner Rife 1993, After AAW 196 |
|
15a.
|
Body yellowish-white with gut apparent
through the translucent integument; eyes with one ocellus and flagellum
with two articles.
|
Trichorhina
tomentosa
|
15b.
|
Body rose or pink in color, or completely
white.
|
[16]
|
|
G
Stoner Rife 1993, After AAW 196 |
|
16a.
|
Eyes with one tiny ocellus, body white,
antennae short.
|
Miktoniscus
medcofi
|
16b.
|
Eyes with one large ocellus, body pink or
rose-red color (occasionally white), with a double yellow longitudinal
stripe, antennae long.
|
Androniscus
dentiger
|
|
G
Stoner Rife 1993, After AAW 196 |
|
17a.
|
Lateral margins of head expanded and with
conspicuous cleft, frontal margin with carina projection between basal
segments of second antenna.
|
Lirceus
spp.
|
17b.
|
Lateral margins of head not expanded, not
notched or cleft, no frontal carina.
|
Caecidotea
spp.
|
|
G
Stoner Rife 1993, After AAW 196 |
|
REFERENCES
Anonymous. 1964. Key to the Isopoda of Ohio. Unpub. Rep.
The Entomology Greenhouse, Ohio State University, Columbus, Ohio.
Hopkin, S.P. 1991. A key to the woodlice of Britan and
Ireland. Field Studies. 7:559-650.
Keeney, G.D. 1990. Some exotic terrestrial isopods
(Oniscoidea) form the Columbus Zoo Exploration Center, Powell, Ohio: two new
state records. Ohio J. of Sci. 90(4): 133-134.
Rife, G.S. 1993. A scanning electron microscopy study of
cuticular structure in some Ohio terrestrial isopods (Crustacea:Isopoda:
Oniscoidea). PhD Diss. Bowling Green State University, Bowling Green, Ohio. Pp
1-123.