Lost River - Karst Information Portal

2007 NSS Convention Guidebook
inermis from the Ohio River to about Monroe
County, then Orconectes inermis testii in Monroe
and Owen counties. It occurs only in the southcentral
karst. The troglophile Cambarus laevis
occurs in both of Indiana’s karst areas, and its
paleness and relatively small eyes can lead to it
being mistaken for its eyeless relative.
Isopods – The cave isopod Caecidotea stygia
is ubiquitous in the caves of the south-central
karst, and Clark and Jefferson counties in
southeastern Indiana. There it is replaced by the
related Caecidotea rotunda in Jennings, Ripley,
and Decatur counties. The two species look
essentially identical. The familiar pillbugs that
roll into balls are also isopods, and almost all
have been introduced from Europe. The native
land isopods are tiny and not commonly seen.
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Cave isopod (Caecidotea).
Amphipods – The common amphipods
in Indiana caves are in the genus Crangonyx.
Packard’s groundwater amphipod (C. packardi)
is found in both karst areas. Barr’s (C. barri) and
the Indiana (C. indianensis) cave amphipods
occur in the south-central karst, while Lewis’
cave amphipod (C. lewisi) is limited to the
southeastern karst. Several undescribed species
of Stygobromus are tiny and extremely rare,
mostly found in drip water where they fall from
their native habitats in the epikarst.
Millipedes – Several species of Pseudotremia
are found in caves of the counties along the
Ohio River, but most are very rare. They are
typically about three quarters of an inch in
length and vary from white to bluish, all with
reduced eyes. The three more common species
are the Indiana cave millipede (P. indianae) in
the Blue River basin, Salisa’s cave millipede (P.
salisae) from the Little Blue River, and the Clark
cave millipede (P. nefanda) in Clark County.
Sollman’s cave millipede (Scoterpes sollmani)
is completely white and eyeless. It is known
only from two caves in Harrison and Crawford
counties. In the northern half of the southcentral
karst the straw-colored Bollman’s cave
millipede (Conotyla bollmani) is common.
Cave millipede (Pseudotremia).
Spiders – The most obvious spider in
Indiana is the cave orb-weaver (Meta ovalis),
first described from the Marengo Cave System.
This large troglophile spins its prominent orb
webs from cave walls, sometimes in association
with its egg sacs. Several species of troglobitic
spiders occur in Indiana, but most are tiny (in
the neighborhood of 2 millimeters) sheet-web
spiders. The subterranean sheet-web spider
(Phanetta subterranea) probably occurs in
nearly every cave in Indiana, where it is found