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Texas Endangered Invertebrate Species
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RECOVERY
PLAN FOR ENDANGERED
KARST INVERTEBRATES IN
TRAVIS AND Prepared
by: and Ruth
A. Stanford Edited
by: For: Region
2 LITERATURE
CITATIONS Literature
citations for this document should read as follows: U. S. Fish and Wildlife Service.
1994. Recovery Plan for Endangered Karst Invertebrates in
Travis and Williamson Counties, Additional copies may be
purchased from: Fish and Wildlife Reference
Service (301) 492-6403 or 1-800-582-3421 The fee for the plan varies depending
on the number of pages of the plan. The study of caves and karst in process. Much of the information
presented in this plan was derived from research in
progress. Besides William R. Elliott, who prepared the initial
draft of this plan, contributors include James R.
Reddell, George Veni, Mike Warton, and Bill provided
significant comments to William Elliott in the early
development stages of this plan. EXECUTIVE SUMARY OF THE RECOVERY PLAN OR
ENDANGERED KARST INVERTEBRATES IN TRAVIS AND Current
Species’ Status: All seven species (Texella reddelli, Texella reyesi,
Tartarocreagris texana, Neoleptoneta
myopica, Rhadine persephone,
Texamaurops reddelli, and Batrisodes texanus) are
endangered. They spend their entire lives underground and are endemic to
karst formations (caves, sinkholes, and other subterranean voids) in Travis
and Williamson counties, Habitat
Requirements and Limiting Factors: All tend to
occur in the dark
zone of caves, but occasionally in deep twilight. All prefer
relative humidities near 100%, but some may be less sensitive to
drying than others. Presumably all are predators upon small or
immature arthropods, or, as in the case of the ground beetle,
possibly cave cricket eggs. TABLE OF CONTENTS Disclaimer Literature Citations Table of Contents I. Introduction and
Background A.
Taxonomic and Legal Classification, and Description B.
Distribution C.
Habitat, Ecosystem, and Ecology D.
Reasons for Listing and Current Threats II. Recovery A.
Objective and Criteria B.
Recovery Outline C.
Narrative Outline for Recovery Actions III. Implementation Schedule IV. Appendices A.
Glossary B.
List of Commenters C.
Summary of Comments and USFWS Response Tables Table 1 – 3 Figures Figure 1 - 11 I. INTRODUCTION AND BACKGROUND [Appendix A contains a glossary
of terms used in this recovery plan. Terms defined in
the glossary are indicated by BOLD face type in the text.] This
recovery plan covers seven species of karst invertebrates and their
ecosystems. The seven species are: Texella
reddelli ( Texella reyesi
( Tartarocreagris
texana ( Neoleptoneta
myopica (Tooth Cave spider), Rhadine
persephone ( Texamaurops
reddelli ( Batrisodes
texanus ( Five species (Texella
reddelli, Tartarocreagris texana, Neoleptoneta
myopica, Rhadine persephone, and Texamaurops reddelli) were listed as
endangered on (53 FR 36029).
A refinement of the taxonomy has expanded this group into seven distinct
species (58 FR 43818) Because Texella reyesi and
Batrisodes texanus were considered to be populations of Texella
reddelli and Texamaurops
reddelli, respectively, at the time of listing, they are also considered to be
listed as endangered under the Endangered Species Act (58.FR
43818). Of
the seven listed species, three are insects (one ground beetle and two mold
beetles) and four are arachnids (one pseudoscorpion, one spider,
and two harvestmen) . All are troglobites, which spend their entire lives underground and have small or absent eyes,
elongated appendages, and other adaptations to the
subterranean environment. Although troglobites must complete
their life cycles underground, they are dependent
on moisture and nutrient inputs from the surface.
Troglobites typically inhabit the dark zone of the cave
where temperature and humidity are relatively constant. Most are
usually found under rocks. All seven species appear to be
predators and are found in relatively small numbers. Each
species may have a different preferred microhabitat
and may depend on certain prey species for survival.
Troglobites tend to be rare and limited in distribution and
are of special interest to evolutionary biologists,
ecologists, biogeographers, and educators. Their limited
distributions combined with low reproductive rates, ecological
specialization, and other factors, make troglobites
especially vulnerable to habitat destruction, fire ant
infestations, pollution, and other factors. A. Taxonomic
and Legal Classification, and Description Note on Common
Names and Arthropod Systematics Few
invertebrates have common names. Common names are often used for convenience sake
and may become standardized for well-known or commonly
studied species. The common names for the karst invertebrates
included in this recovery plan are given in this section
(A) However, because there are no official common names for
these invertebrates, because taxonomy is most clearly
understood in terms of scientific names, and because
most biologists working with these species refer to them by
scientific name, we use scientific names throughout this
plan. Scientific
names are sometimes changed by scientists according to the International
Code of Zoological Nomenclature. As taxonomists
study certain groups, they publish descriptions of new or
previously unrecognized species or assign known species
to different groups. For example, the spider Leptoneta
myopica was reassigned to the All
of the listed species are members of the Phylum Arthropoda. With some arthropods,
it is important to obtain mature male specimens for
study. In many cases, as in the mold beetles and
harvestmen, species are identified based on the structure of the
male genitalia. These structures are highly
species-specific and believed to be under genetic control. Often a
first collection from a cave contains only immature and
female specimens. Other species, such as the ground
beetles, pseudoscorpions, and several species of spiders
(including Neoleptoneta myopica), can be
differentiated based on male or female structures (such as the
ovipositor), as long as an adult specimen is obtained. SPECIES 1 — Scientific
name: Neoleptoneta myopica (Gertsch), formerly Leptoneta
myopica Gertsch Common Name: Taxonomic
Classification: Class Arachnida (arachnids), Order Araneae
(spiders), Infraorder Araneomorphae (true spiders), Spiders and other arachnids are
not insects. Unlike insects, arachnids possess four
pairs of legs, pedipalps, and chelicerae,
and lack antennae. Insects have three pairs of legs,
mandibles, and antennae. Leptonetids are minute spiders
with six eyes, commonly found in caves and similar
habitats. Some leptonetid spiders in eyeless, but members of this
family typically have small eyes. Original
Description: Gertsch (1974) Type Specimen: Male holotype,
County, Reddell. Female specimen
described but not designated as paratype. Type
specimens are deposited in the Other
Taxonomic Literature: Brignoli (1972) erected the genus Neoleptoneta for
all spiders and reserved the genus Leptoneta
for other regions. In 1977, Brignoli
formally removed Leptoneta myopica to Neoleptoneta.
The validity of Neoleptoneta was further supported by Platnick
(1986). This recovery plan follows these two
authorities in using the name Neoleptoneta. Selected
characteristics: A small, whitish, longlegged troglobitic spider with six obsolescent
eyes. Eyes medium sized, without dark
pigment; front eye row moderately recurved; eyes subcontiguous and subequal in size; posterior eyes
subcontiguous, set back from anterior lateral eyes. First leg
in both sexes 6.1 times as long as carapace. Body length 1.6 mm, carapace 0.7 mm long and 0.5 mm
wide, abdomen 0.9 mm long and 0.5 mm wide. Tibia of
male palpus with thin retrolateral process set
with curved spine. Intraspecific
Variation: Not known. Distinctiveness: Neoleptoneta
myopica is related to several other troglobites in the
Balcones Fault Zone of County; N. concinna from a
cave and a mine in Travis County; N. devia from one
cave in N. microps from one cave
in Geographically, the Neoleptoneta
species closest to N. myopica is N. devia
from only 2.5 km from Cave, the type locality. Neoleptoneta
devia is dull yellow with a whitish abdomen and
the eyes enclose a dusky field, whereas N.
myopica is whitish and has very reduced eyes that are not
set in a dusky field. Neoleptoneta
devia and
N. concinna, the other two species in Gertsch (1974) did not discuss
evolutionary relationships among the six that he described. Listed: Endangered; Recovery
Priority: 2C. According to the 13. 5. Fish and Wildlife Service’s (USFWS)
criteria (48 FR 51985) this indicates a species with a
high degree of threats, high potential for
recovery, and in conflict with construction or development
projects or other forms of economic activity. SPECIES 2 — Scientific
name: Tartarocreagris texana (Muchmore), formerly Microcreagris
texana Muchmore. Common Name: Taxonomic
Classification: Class Arachnida (arachnids), Order Pseudoscorpiones
(pseudoscorpions), Family Neobisiidae. Pseudoscorpions are
quite distinct from scorpions in lacking a postabdomen (tail), stinger, and book
lungs. Most pseudoscorpions are
no more than a few mm long. Original
Description: Muchmore (1969). Type Specimen: Female
holotype, County, Reddell. Deposited in History. Male known from Other
Taxonomic Literature: Muchmore (1992) reassigned Microcreagris
texana to Tartarocreagris, a genus described by Curcic (1984),
based on the female holotype of M. infernalis from
Inner Space Cavern, collected males of both species,
it became clear that M. texana also belonged
in Tartarocreagris. Curcic (1989) had previously reassigned
N. texana to Australinocreagris
Curcic
(1984), which is based on M. grahami from that classification to be
incorrect based on internal male genitalia. Muchmore (1992)
described a new |